Anti-mud foam-stabilizing slump retaining material and preparation method thereof

Abstract

The invention relates to the technical field of building admixtures, in particular to an anti-mud foam-stabilizing slump retaining material and a preparation method thereof. The preparation method comprises the following steps: dropwise adding a comonomer mixture solution, an initiator aqueous solution and a molecular weight regulator aqueous solution into a reaction kettle filled with water, stirring and reacting at the reaction temperature of 5-80 DEG C for 1.0-2.0 hours, continuously reacting for 0.5-2.0 hours after dropwise adding to obtain a copolymerization product, and regulating the pH value to 5-7 by using alkali to obtain the anti-mud foam-stabilizing slump retaining material, the prepared slump retaining material is excellent in slump retaining performance, has a very good air entraining effect, is more stable in bubbling when being applied to concrete, can further improve the lubricating effect of particles in multiple systems of the concrete, endows the concrete with an excellent anti-mud function, can reduce concrete segregation and bleeding, has an early strength effect, and has a good anti-mud effect. Even in the harsh process of stirring, long-distance transportation, frequent loading and unloading and even final pouring of concrete, bubbles can still keep the integrity and do not crack or overflow.

Description

Technical Field

[0001] The invention relates to the technical field of building admixtures, and in particular to an anti-mud and foam-stabilizing collapse-preserving material and a preparation method thereof. Background Art

[0002] As an important component of concrete, concrete admixture plays an important role in the concrete mixing process. In particular, concrete water reducers have brought about a huge leap in the workability, mechanical properties, and durability of concrete. However, due to the large-scale development of sand and gravel raw materials used in modern concrete, the reserves of high-quality sand and gravel are becoming increasingly scarce. Usually, the mud content in sand and gravel is high and the particle grading is poor, which seriously affects the properties of concrete. In particular, excessive mud content will reduce the water-reducing performance of the water reducer in concrete, or even make it ineffective, resulting in a significant reduction in the initial slump and slump loss over time of the concrete, which also poses a greater threat to the workability and durability of the concrete.

[0003] In order to solve the above problems, slump-preventing agents are often added to the system to alleviate them. However, traditional slump-preventing agents have poor dispersion ability in the early stage of cement hydration and weak slump-preventing effect. At the same time, the action time of traditional slump-preventing agents is generally 1 to 2 hours, and the slump loss is fast. For concrete that needs to be transported over long distances, especially for small slump concrete that needs to be transported over long distances, the slump-preventing effect is not good.

[0004] Patent CN104961377A, published on October 7, 2015, discloses a method for preparing a polycarboxylate water-reducing agent by introducing a sacrificial agent containing a large amount of anions, such as potassium polyacrylate aqueous solution or sodium polyacrylate methacrylic acid sulfonate, which can improve the adaptability of the polycarboxylate water-reducing agent to high-mud content sand and gravel. Patent CN106517857A, published on November 14, 2016, discloses a polycarboxylate water-reducing agent specifically for high-mud system ultra-long slump-retaining concrete, which is synergistically anti-mud by compounding slow-release, slow-setting, slump-retaining and organic cationic polymers to extend the slump-retaining time.

[0005] The effect of the mud-resistant admixtures prepared by the prior art in solving the problem of high mud content is not satisfactory. Due to gas loss, it cannot meet the needs of long-distance transportation of small slump concrete coagulation and collapse protection. In addition, it is difficult to use and the effect is unstable, making it difficult to produce and apply on a large scale. Therefore, it is of great significance to the entire industry to develop a foam-stable collapse protection material with high mud resistance. Summary of the invention

[0006] In order to solve the problem of insufficient collapse protection of concrete in long-distance transportation mentioned in the above background, the present invention provides a method for preparing an anti-mud and foam-stabilizing collapse protection material, comprising the following steps: The copolymerization monomer mixture solution, the initiator aqueous solution and the molecular weight regulator aqueous solution are dripped into a reaction kettle filled with water and stirred to react. The reaction temperature is 5 to 80°C and the dripping time is 1.0 to 2.0 hours. After the dripping is completed, the reaction is continued for 0.5 to 2.0 hours to obtain a copolymer product. Then, the pH is adjusted to 5 to 7 with alkali to obtain an anti-mud and foam-stabilizing collapse-preserving material. The method for preparing the copolymer monomer mixture solution is as follows: a foam stabilizing functional monomer, an esterification monomer, an unsaturated phosphate monomer, an unsaturated carboxylic acid or an unsaturated carboxylic anhydride, an unsaturated carboxylic acid ester small monomer, and a polyether macromonomer are mixed in a mass ratio of (1-6): (3-8): (1-3): (2-15): (12-30): 200, and water is added to dissolve the mixture to obtain the copolymer monomer mixture solution; Wherein, the structural formula of the foam stabilizing functional monomer is: ; Wherein, R1 and R2 are polyether chains obtained by polymerization of ethylene oxide and propylene oxide, respectively, and R3 is -CH2- or -C2H4-.

[0007] On the basis of the above embodiment, further, the weight average molecular weight of the foam stabilizing functional monomer is 400-1000.

[0008] On the basis of the above embodiment, further, the preparation method of the foam stabilizing functional monomer is: S100, adding initiator and catalyst into the reaction kettle, and evacuating the reactor to a vacuum, preferably to -0.1 MPa; S200, replace with N2 1 to 5 times, raise the reaction temperature to 100 to 180°C, introduce alkylene oxide into the reactor, the reaction pressure is 0.2 to 5 MPa, and react for 1 to 3 hours; S300, when the pressure of the reactor stops decreasing, evacuate the reactor, preferably to -0.1 MPa, and then introduce the epoxy sulfonic acid compound into the reactor, maintaining the temperature at 100-180°C; S400, when the pressure in the reactor stops decreasing, the reaction is finished, and the foam stabilizing functional monomer is obtained.

[0009] On the basis of the above embodiment, further, the initiator is tetrapentanol allyl ether; The catalyst is one or more of sodium methoxide, sodium tert-butoxide, sodium ethoxide, lithium aluminum hydroxide, sodium hydroxide, potassium hydroxide, sodium cyanide, and metallic sodium, and the amount of the catalyst is 0.1% to 0.3% of the mass of ethylene oxide and / or propylene oxide; The alkylene oxide is ethylene oxide and / or propylene oxide, and the number of the alkylene oxides is 2 to 12.

[0010] On the basis of the above embodiment, further, the epoxysulfonic acid compound is any one of oxirane-2-yl methane sulfonate and 2,3-epoxypropyl methane sulfonate.

[0011] On the basis of the above embodiment, the preparation method of the esterification monomer is further as follows: hydroxy imidazoline, unsaturated fluorophenyl acid and polymerization inhibitor are placed in a reaction kettle equipped with a condensing device, and the temperature is raised to 80-160° C. under nitrogen protection, and then a catalyst is added, and the temperature is kept for reaction for 2-6 hours, and water is removed by vacuuming or nitrogen-carrying during the reaction, and the temperature is cooled to room temperature after the reaction is completed, so as to obtain the esterification monomer; The molar ratio of hydroxyimidazoline to unsaturated fluorophenyl acid is 1: (0.5-5), the amount of catalyst used is 0.2%-3.0% of the total mass of hydroxyimidazoline and unsaturated fluorophenyl acid, and the amount of inhibitor used is 0.5%-3.0% of the total mass of hydroxyimidazoline and unsaturated fluorophenyl acid.

[0012] On the basis of the above embodiment, further, the hydroxy imidazoline is at least one of lauryl hydroxyethyl imidazoline and myristyl hydroxyethyl imidazoline; The unsaturated fluorophenyl acid structural formula is: , In the formula, R on the benzene ring is -CF3 or -F or 2 -Fs, and is in the ortho, meta or para position to the acrylic acid group.

[0013] On the basis of the above embodiment, further, the unsaturated phosphate monomer P is at least one of 2-methyl-2-acrylic acid-2-hydroxyethyl phosphate, 10-(2-methacryloyloxy)monodecyl phosphate, and 2-(dimethoxyphosphoryl)methyl acrylate; The unsaturated carboxylic acid or unsaturated carboxylic anhydride is at least one of acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, acrylic anhydride and itaconic anhydride; The unsaturated carboxylic acid ester is at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, 4-hydroxybutyl glycidyl acrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,3-propylene glycol diacrylate, 1,5-pentanediol dimethacrylate, and glycerol 1,3-dimethacrylate; The polyether macromonomer is at least one of 3-methyl-3-butene-1-polyethylene glycol, 2-methylallyl polyethylene glycol, ethylene glycol monovinyl polyethylene glycol ether and 4-hydroxybutyl vinyl polyoxyethylene ether with a molecular weight of 1000 to 6000.

[0014] On the basis of the above embodiment, further, the total amount of water makes the mass concentration of the copolymer product be 20% to 80%, the amount of the initiator is 0.5% to 3.0% of the total mass of the solute in the copolymer mixture solution, and the amount of the molecular weight regulator is 0.2% to 2.0% of the total mass of the solute in the copolymer mixture solution; The initiator is a water-soluble inorganic peroxide initiator, a water-soluble redox initiator system or a water-soluble azo initiator, that is, the water-soluble inorganic peroxide initiator is at least one of ammonium persulfate and potassium persulfate; The water-soluble redox initiation system is at least one of hydrogen peroxide-bleaching powder, hydrogen peroxide-ascorbic acid, and persulfate-sodium bisulfite; The water-soluble azo initiator is at least one of azobisisobutylamidine hydrochloride, azobisisopropylimidazoline hydrochloride, azobiscyanovaleric acid, and azobisisopropylimidazoline; The molecular weight regulator is at least one of thioglycolic acid, mercaptopropionic acid, mercaptoethanol, isopropanol, sodium hypophosphite, trisodium phosphate, sodium formate, sodium acetate and dodecanethiol.

[0015] The present invention also provides an anti-mud and foam-stabilizing collapse-preventing material prepared by any of the above methods for preparing the anti-mud and foam-stabilizing collapse-preventing material.

[0016] The technical solution of the present invention has the following principles and beneficial effects: 1. The anti-mud and foam-stabilizing collapse-preserving material provided by the present invention introduces foam-stabilizing functional monomers, esterification monomers, and phosphate monomers into the polycarboxylic acid structure to form a micro-crosslinked network structure, which is interlaced with the side chains of ether macromonomers. This structure is like an intricate maze, interweaving with the side chains of ether macromonomers to form a compact and orderly arrangement. This unique molecular arrangement not only greatly enhances the electrostatic repulsion between molecules, making the structure more stable, but also can build a dense hydration film on the surface of concrete, which not only protects the stable existence of bubbles, but also has excellent air entraining performance and greatly improves its effect of stabilizing bubbles. Even in the harsh process of mixing, long-distance transportation, frequent loading and unloading, and even final pouring of concrete, the bubbles can still maintain their integrity without breaking or overflowing.

[0017] 2. The molecular structure of the foam-stabilizing functional monomer involved in the technical solution of the present invention has the effect of inhibiting the water absorption and expansion of clay, can reduce the adsorption of concrete admixtures in clay, and improve the dispersion effect and dispersion stability of polycarboxylic acid water-reducing agent in concrete with high clay content; it also cleverly regulates the rate of hydrolysis reaction in the molecular chain, effectively avoiding the problem of concrete bleeding and re-enlargement caused by the too rapid hydrolysis process, and ensures the uniformity and stability of concrete quality. The overall performance of concrete is further improved through synergistic effect, which is particularly suitable for small slump concrete projects with long-term collapse protection requirements.

[0018] 3. In the preferred embodiment, the preparation method of the foam-stabilizing functional monomer is to prepare the foam-stabilizing functional monomer through addition polymerization of tetrapentanol allyl ether, alkylene oxide and epoxysulfonic acid compound; and the esterification functional monomer is prepared by esterification of hydroxyimidazoline with unsaturated fluorophenyl acid, and then the esterification functional monomer is introduced into the main chain of the polycarboxylic acid molecule with unsaturated phosphate, polyether macromonomer, unsaturated carboxylic acid (anhydride) and unsaturated carboxylic acid ester monomer. The prepared collapse-preserving material not only has excellent collapse-preserving performance and good air-entraining effect, but also has more stable foaming when applied to concrete, can further improve the lubrication effect of particles in multiple systems of concrete, give it anti-mud function, reduce concrete segregation and bleeding, and has excellent early strength effect. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] 1. The present invention provides the following structural examples of foam stabilizing functional monomers: ; Wherein, R1 and R2 are polyether chains obtained by polymerization of ethylene oxide and propylene oxide, respectively, and R3 is -CH2- or -C2H4-, and its weight average molecular weight is 400-1000.

[0021] 2. The present invention provides the following preparation examples of anti-mud and foam-stabilizing collapse-preserving materials: The preparation example of the foam stabilizing functional monomer A is shown in the following table: Table 1 Example Foam stabilizing monomer Initiator / g EO / g PO / g Catalyst, g Temperature 1 / ℃ Temperature 2 / ℃ Capping agent / g Example 1 A1 76.61 97.3 26.1 Sodium methoxide, 0.2 110 160 69.6 Example 2 A2 67.77 109.2 23.1 Sodium hydroxide, 0.3 120 150 61.5 Example 3 A3 60.76 118.5 20.7 Sodium metal, 0.4 130 140 55.2 Example 4 A4 53.40 128.4 18.2 Potassium hydroxide, 0.26 140 130 48.5 Example 5 A5 42.98 142.4 14.6 Sodium ethoxide, 0.33 150 120 39.0 Example 6 A6 48.95 134.4 16.7 Sodium methoxide, 0.42 160 110 44.4 The preparation method of the above embodiment is to add the initiator tetrapentyl alcohol allyl ether and the catalyst to the reactor, evacuate to -0.1 MPa, replace with N2 3 times, heat the reaction to 100-180°C (specifically, temperature 1 in the table), introduce alkylene oxide (wherein EO is ethylene oxide and PO is propylene oxide) into the reactor, and the reaction pressure is 0.2-5 MPa; react for 1-3 hours until the pressure of the reactor no longer decreases, evacuate to -0.1 MPa, and then introduce the end-capping agent ethylene oxide-2-yl methane sulfonate into the reactor, maintain the temperature at 100-180°C (specifically, temperature 2 in the table), and when the pressure of the reactor no longer decreases, the reaction is terminated, and the foam stabilizing functional monomer A of each embodiment is obtained.

[0022] Preparation Example of Esterification Monomer B: Hydroxyimidazoline, unsaturated fluorophenyl acid and polymerization inhibitor are placed in a reaction kettle equipped with a condensing device, and the temperature is raised to 80-160° C. under nitrogen protection, and then a catalyst is added. The reaction is kept warm for 2-6 hours, during which water is removed by vacuuming or nitrogen-carrying. After the reaction is completed, the temperature is cooled to room temperature to obtain an esterified monomer B. The specific implementation example is shown in Table 2: Table 2 Example Esterification monomer Hydroxyimidazoline / mol Unsaturated fluorophenyl acid / mol Inhibitor / % catalyst / % Temperature / ℃ Time / h Example 1 B1 Lauryl Hydroxyethyl Imidazoline: 1 2-Fluorocinnamic acid: 3.2 2,2-Diphenyl-1-picrylhydrazine:2.0 Concentrated sulfuric acid: 0.8 90 6.0 Example 2 B2 Myristyl Hydroxyethyl Imidazolinium: 1 3-Fluorocinnamic acid: 4.0 N-nitrosodiphenylamine: 2.1 Benzenesulfonic acid: 1.2 100 5.0 Example 3 B3 Lauryl Hydroxyethyl Imidazoline: 1 4-Fluorocinnamic acid: 2.8 2,2-Diphenyl-1-picrylhydrazine:2.6 p-Toluenesulfonic acid: 1.5 110 5.0 Example 4 B4 Myristyl Hydroxyethyl Imidazolinium: 1 3-(Trifluoromethyl)cinnamic acid: 3.3 1,1-Diphenyl-2-picrylhydrazine:2.1 Ethylsulfonic acid and dimethylaminopyridine: 1.8 120 4.0 Example 5 B5 Lauryl Hydroxyethyl Imidazoline: 1 2-(Trifluoromethyl)cinnamic acid: 2.9 N-nitrosodiphenylamine: 1.8 Concentrated sulfuric acid: 0.6 100 5.5 Example 6 B6 Myristyl Hydroxyethyl Imidazolinium: 1 4-(Trifluoromethyl)cinnamic acid: 2.2, 2-fluorocinnamic acid: 1.2 1,1-Diphenyl-2-picrylhydrazine:1.2 p-Toluenesulfonic acid:2.0 100 3.5 The foam stabilizing functional monomer A, esterification monomer B, unsaturated phosphate monomer P, unsaturated carboxylic acid (anhydride), unsaturated carboxylic acid ester small monomer, and polyether macromonomer M prepared above are mixed in a mass ratio of (1-6): (3-8): (1-3): (2-15): (12-30): 200, and water is added to dissolve them to obtain a copolymer monomer mixture solution C, as shown in the following table: Table 3 Example Comonomer mixture solution C / g Foam stabilizing monomer A Esterification monomer B Unsaturated phosphate monomer P Unsaturated carboxylic acid (anhydride) / g Unsaturated carboxylic acid ester small monomer / g Polyether macromonomer M / g Water / g Example 1 C1 A1，1.9 B1,3.8 2-Methyl-2-acrylic acid-2-hydroxyethyl ester phosphate, 1.6 Acrylic acid, 6 Hydroxyethyl acrylate, 19; Glycerol 1,3-diisomethacrylate, 9 3-Methyl-3-butene-1-polyethylene glycol, 200 100 Example 2 C2 A2，2.4 B2,4.2 2-(Dimethoxyphosphoryl) methyl acrylate, 2.0 Acrylic acid, 3; Methacrylic acid, 4 Hydroxyethyl acrylate, 15; Hydroxypropyl acrylate, 12 2-Methallyl Polyethylene Glycol, 200 100 Example 3 C3 A3，3.8 B3,5.2 10-(2-Methacryloyloxy)monodecyl phosphate, 2.5 Acrylic acid, 5; Itaconic acid, 3 Hydroxyethyl acrylate, 21; Glycidyl acrylate, 7 Ethylene glycol monovinyl polyglycol ether, 200 100 Example 4 C4 A4，3.0 B4,3.6 2-Methyl-2-acrylic acid-2-hydroxyethyl ester phosphate, 1.2 Acrylic acid, 8; Maleic anhydride, 5 Hydroxyethyl acrylate, 3; Hydroxypropyl acrylate, 16; Ethylene glycol diacrylate, 5 4-Hydroxybutylvinyl polyoxyethylene ether, 200 100 Example 5 C5 A5，4.0 B5,6.6 2-(Dimethoxyphosphoryl) methyl acrylate, 1.6 Acrylic acid, 6g; Acrylic anhydride, 4g 1,3-Dipropylene glycol acrylate, 4; 4-Hydroxybutyl glycidyl acrylate, 2; Hydroxyethyl acrylate, 20 4-Hydroxybutylvinylpolyoxyethylene ether, 160;4-Hydroxybutylvinylpolyoxyethylene ether, 40 100 Example 6 C6 A6，5.2 B6,6.8 10-(2-Methacryloyloxy)monodecyl phosphate, 2.0 Acrylic acid, 3; Acrylic anhydride, 2; Itaconic anhydride, 6 1,3-Dipropylene glycol acrylate, 2; Hydroxypropyl acrylate, 16; Hydroxyethyl acrylate, 6 4-Hydroxybutylvinyl polyoxyethylene ether, 150; 3-methyl-3-butene-1-polyethylene glycol, 50 100 The above-mentioned comonomer mixture solution C, initiator aqueous solution and molecular weight regulator aqueous solution are dripped into a reaction kettle filled with water, and the stirrer is turned on to react. The reaction temperature is 5-80°C and the dripping time is 1.0-2.0h. After the dripping is completed, the reaction is continued for 0.5-2.0h to obtain a copolymer product, and then the pH is adjusted to 5-7 with alkali to obtain an anti-mud and stable foam type collapse-preserving material D, as shown in the following table: Table 4

[0023] The present invention provides the following comparative examples of collapse-preventing materials: Comparative Example 1 The commercially available model is SBT concrete collapse prevention material X1.

[0024] Comparative Example 2 Using the process of Example 1 as the basic process, without using A1 for synthesis and keeping other reaction conditions unchanged, X2 was obtained.

[0025] Comparative Example 3 Using the process of Example 1 as the basic process, without using B1 and keeping other reaction conditions unchanged, X3 was obtained.

[0026] Comparative Example 4 The process of Example 1 is used as the basic process, without using A1 for synthesis. After the copolymerization reaction is completed, a commercially available foam stabilizing and air entraining agent Y1 is compounded and added in an equal amount to A1, and other reaction conditions remain unchanged to prepare X4.

[0027] Comparative Example 5 The process of Example 1 is used as the basic process, without using B1 for synthesis. After the copolymerization reaction is completed, the commercial anti-mud agent KN1 is compounded, and other reaction conditions remain unchanged to prepare X5.

[0028] The performance test is as follows: The collapse-preserving materials prepared in Examples 1 to 6 and Comparative Examples 1 to 5 were compounded with PointTS8, a water-reducing agent of Kezhijie, at a solid-to-solid ratio of 5:5 to form a sample with a solid content of 8%. When the dosage of Examples 1 to 6 was 1.1% (relative to the amount of cementitious material used), the water reduction rates were all higher than 38%, the 1d compressive strength ratio was all higher than 200%, the 7d compressive strength ratio was all higher than 190%, the 28d compressive strength ratio was all higher than 180%, and the 28d shrinkage ratio was all less than 50%.

[0029] Yuexiu P.O42.5 ordinary Portland cement is used, and the concrete mix ratio is: cement 320kg / m 3 、Fly ash 50kg / m 3 、Mineral powder 50kg / m 3 、Mechanical sand 780kg / m 3 、Stone 1020kg / m 3 , bentonite 15kg / m 3 , water 175kg / m 3 According to the above admixture formula, the performance of the slump-preserving materials prepared in Examples 1 to 6 and Comparative Examples 1 to 5 was compared, and the dosage of the admixture was adjusted to make the initial slump of the concrete (150±20) mm. The test indicators included the slump of the concrete over time at 0h, 1h, 2h, 3h and 4h, the air content, the bleeding rate and the compressive strength at each age. The concrete test results are shown in the following table: Table 5

[0030] According to the above-mentioned admixture formula, the bentonite was replaced with machine-made sand in the concrete mix ratio. The performance of the slump-preventing materials prepared in Examples 1 to 6 and Ratios 1 to 5 was compared. The dosage of the admixture was adjusted to make the initial slump of the concrete (150±20) mm. The test indicators included the slump of the concrete after 0h, 1h, 2h, 3h and 4h, the air content, and the water bleeding rate. The concrete test results are shown in the following table.

[0031] Table 6

[0032] From the test results in Table 5 and Table 6 above, it can be obtained that: 1) The slump-preserving material prepared by the present invention is applied to small slump concrete to achieve long-term slump preservation of 4 hours. The slump is stable during the process, does not return to a large slump, and does not lag in water seepage. With or without the addition of bentonite, the difference in the amount of admixture and the performance of concrete is not large, the air content is very stable, and it has a good foam stabilizing effect. For comparative examples 1 to 5, after the addition of bentonite, the amount of admixture is increased as a whole, and there is a phenomenon of lag return to a large slump, and the difference in water seepage rate is large, indicating that the slump-preserving performance of the patent of the present invention is stable and has obvious anti-mud advantages.

[0033] 2) Comparing X1 and D1, the commercially available slump-preserving material showed an obvious slump increase within 2 hours, and the air content out of the machine was relatively high. The air content gradually decreased with time, resulting in air loss, unstable bubbles, and low concrete strength at 1 day. The water seepage rate of X1 was relatively high.

[0034] 3) By comparing X2 with D1, the preparation of the collapse-preserving material does not introduce the homemade foam-stabilizing functional monomer A1, the dosage of the admixture is higher than that of the collapse-preserving material D1 prepared by the present invention, and the slump returns to a large value within 2 hours, and the loss begins to appear after 2 hours, and the collapse-preserving is poor. Secondly, the air content is unstable, the air content out of the machine is high, the air loss is fast, and the air content is low after 2 hours. In addition, the collapse-preserving is fast, and the concrete does not collapse. There is not much difference in strength, and the water bleeding rate of X2 is higher.

[0035] 4) By comparing X3 with D1, the preparation of the collapse-preserving material does not introduce the homemade B1. It can be seen that the dosage of the admixture is much higher than that of the patent of the present invention. The concrete returns after 1 hour, and the loss is large from 1 hour to 2 hours. At 2 hours, the concrete does not collapse. The collapse-preserving performance is not as good as that of the patent of the present invention. In terms of air content, the bubbles are well maintained for 1 hour, and air loss begins to occur after 2 hours. The foam stabilizing performance in the later period is poor, and the strength at 1 day is low. The water seepage rate of X3 is high.

[0036] 5) Comparing X4 with D1, A1 was replaced by a commercially available air-entraining agent compound. The admixture dosage increased, and the slump showed a trend of increasing and then decreasing, and a reversal phenomenon occurred. The loss was very large in 3 hours and could not be maintained for 4 hours. The air content was unstable and the air loss was large. The strength at each age was lower than that of the patented product of the present invention, which had a greater impact on the strength and a higher water seepage rate.

[0037] 6) By comparing X5 and D1, the commercially available anti-mud agent replaced B1, the admixture dosage became higher, the concrete returned to a large size after 1 hour, the slump was maintained for 2 hours, and the slump began to decrease after 2 hours, and the water seepage rate was relatively high; by comparing D1, X3 and X5 at the same time, it can be seen that the collapse protection material prepared by the present invention has better anti-mud and collapse protection effects, and good foam stabilizing performance.

[0038] In summary, the improved anti-mud and foam-stabilizing collapse-preserving material of the present invention can build a dense hydration film on the surface of concrete, which not only protects the stable existence of bubbles, makes it have excellent air entraining performance, but also greatly improves its effect of stabilizing bubbles. Even in the harsh process of concrete mixing, long-distance transportation, frequent loading and unloading, and even final pouring, the bubbles can still maintain their integrity without breaking or overflowing. The present invention effectively avoids the problems of concrete bleeding and enlargement caused by the too rapid hydrolysis process, ensures the uniformity and stability of concrete quality, further improves the overall performance of concrete, and has excellent anti-mud effect. It is particularly suitable for small slump concrete projects with long-term collapse protection requirements, and has important practical application value.

[0039] Finally, it should be noted that 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an anti-mud and foam-stabilizing collapse-preserving material, characterized in that: The following steps are involved: The copolymerization monomer mixture solution, the initiator aqueous solution and the molecular weight regulator aqueous solution are dripped into a reaction kettle filled with water and stirred to react. The reaction temperature is 5 to 80°C and the dripping time is 1.0 to 2.0 hours. After the dripping is completed, the reaction is continued for 0.5 to 2.0 hours to obtain a copolymer product. Then, the pH is adjusted to 5 to 7 with alkali to obtain an anti-mud and foam-stabilizing collapse-preserving material. The method for preparing the copolymer monomer mixture solution is as follows: a foam stabilizing functional monomer, an esterification monomer, an unsaturated phosphate monomer, an unsaturated carboxylic acid or an unsaturated carboxylic anhydride, an unsaturated carboxylic acid ester small monomer, and a polyether macromonomer are mixed in a mass ratio of (1-6): (3-8): (1-3): (2-15): (12-30): 200, and water is added to dissolve the mixture to obtain the copolymer monomer mixture solution; Wherein, the structural formula of the foam stabilizing functional monomer is: ； Wherein, R1 and R2 are polyether chains obtained by polymerization of ethylene oxide and propylene oxide, respectively, and R3 is -CH2- or -C2H4-.

2. The method for preparing the anti-mud and foam-stabilizing collapse-preserving material according to claim 1, characterized in that: The weight average molecular weight of the foam stabilizing functional monomer is 400-1000.

3. The method for preparing the anti-mud and foam-stabilizing collapse-preserving material according to claim 1, characterized in that: The preparation method of the foam stabilizing functional monomer is as follows: S100, adding an initiator and a catalyst into a reaction kettle, and evacuating the reactor; S200, replace with N2 1 to 5 times, raise the reaction temperature to 100 to 180°C, introduce alkylene oxide into the reactor, the reaction pressure is 0.2 to 5 MPa, and react for 1 to 3 hours; S300, when the pressure of the reactor stops decreasing, evacuate the reactor, and then introduce the epoxy sulfonic acid compound into the reactor, maintaining the temperature at 100-180°C; S400, when the pressure in the reactor stops decreasing, the reaction is finished, and the foam stabilizing functional monomer is obtained.

4. The method for preparing the anti-mud and foam-stabilizing collapse-preserving material according to claim 3, characterized in that: The initiator is tetrapentanol allyl ether; The catalyst is one or more of sodium methoxide, sodium tert-butoxide, sodium ethoxide, lithium aluminum hydroxide, sodium hydroxide, potassium hydroxide, sodium cyanide, and metallic sodium, and the amount of the catalyst is 0.1% to 0.3% of the mass of ethylene oxide and / or propylene oxide; The alkylene oxide is ethylene oxide and / or propylene oxide, and the number of the alkylene oxides is 2 to 12.

5. The method for preparing the foam stabilizing functional monomer according to claim 3, characterized in that: The epoxysulfonic acid compound is any one of oxirane-2-yl methane sulfonate and 2,3-epoxypropyl methane sulfonate.

6. The method for preparing the anti-mud and foam-stabilizing collapse-preserving material according to claim 1, characterized in that: The preparation method of the esterification monomer is as follows: hydroxy imidazoline, unsaturated fluorophenyl acid and a polymerization inhibitor are placed in a reaction kettle equipped with a condensing device, and the temperature is raised to 80-160° C. under nitrogen protection, and a catalyst is added, and the temperature is kept for reaction for 2-6 hours, water is removed, and the temperature is lowered to room temperature after the reaction is completed, so as to obtain the esterification monomer; The molar ratio of hydroxyimidazoline to unsaturated fluorophenyl acid is 1: (0.5-5), the amount of catalyst used is 0.2%-3.0% of the total mass of hydroxyimidazoline and unsaturated fluorophenyl acid, and the amount of inhibitor used is 0.5%-3.0% of the total mass of hydroxyimidazoline and unsaturated fluorophenyl acid.

7. The method for preparing the anti-mud and foam-stabilizing collapse-preserving material according to claim 6, characterized in that: The hydroxy imidazoline is at least one of lauryl hydroxyethyl imidazoline and myristyl hydroxyethyl imidazoline; The unsaturated fluorophenyl acid structural formula is: ； In the formula, R on the benzene ring is -CF3 or -F or 2 -Fs, and is in the ortho, meta or para position to the acrylic acid group.

8. The method for preparing the anti-mud and foam-stabilizing collapse-preserving material according to claim 1, characterized in that: The unsaturated phosphate monomer P is at least one of 2-methyl-2-acrylic acid-2-hydroxyethyl ester phosphate, 10-(2-methacryloyloxy) monodecyl phosphate, and 2-(dimethoxyphosphoryl)methyl acrylate; The unsaturated carboxylic acid or unsaturated carboxylic anhydride is at least one of acrylic acid, methacrylic acid, itaconic acid, maleic anhydride, acrylic anhydride and itaconic anhydride; The unsaturated carboxylic acid ester is at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, 4-hydroxybutyl glycidyl acrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,3-propylene glycol diacrylate, 1,5-pentanediol dimethacrylate, and glycerol 1,3-dimethacrylate; The polyether macromonomer is at least one of 3-methyl-3-butene-1-polyethylene glycol, 2-methylallyl polyethylene glycol, ethylene glycol monovinyl polyethylene glycol ether and 4-hydroxybutyl vinyl polyoxyethylene ether with a molecular weight of 1000 to 6000.

9. The method for preparing the anti-mud and foam-stabilizing collapse-preserving material according to claim 1, characterized in that: The total amount of water is such that the mass concentration of the copolymer product is 20% to 80%, the amount of the initiator is 0.5% to 3.0% of the total mass of the solute in the copolymer monomer mixture solution, and the amount of the molecular weight regulator is 0.2% to 2.0% of the total mass of the solute in the copolymer monomer mixture solution; The initiator is a water-soluble inorganic peroxide initiator, a water-soluble redox initiator system or a water-soluble azo initiator, that is, the water-soluble inorganic peroxide initiator is at least one of ammonium persulfate and potassium persulfate; The water-soluble redox initiation system is at least one of hydrogen peroxide-bleaching powder, hydrogen peroxide-ascorbic acid, and persulfate-sodium bisulfite; The water-soluble azo initiator is at least one of azobisisobutylamidine hydrochloride, azobisisopropylimidazoline hydrochloride, azobiscyanovaleric acid, and azobisisopropylimidazoline; The molecular weight regulator is at least one of thioglycolic acid, mercaptopropionic acid, mercaptoethanol, isopropanol, sodium hypophosphite, trisodium phosphate, sodium formate, sodium acetate and dodecanethiol.

10. An anti-mud and foam-stable collapse-preventing material prepared according to the method for preparing an anti-mud and foam-stable collapse-preventing material according to any one of claims 1 to 9.

Images