Preparation method of alkali-free chlorine-free high-early-strength liquid accelerator

Abstract

The invention relates to the technical field of concrete, and discloses a preparation method of an alkali-free chlorine-free high-early-strength liquid accelerator, which comprises the following steps: adding magnesium sulfate, diethanol amine, calcium carbonate, nitrilotriacetic acid modified polyurethane and water into a stirrer, and stirring to obtain the alkali-free chlorine-free high-early-strength liquid accelerator. Polyurethane in nitrilotriacetic acid modified polyurethane can improve the compressive strength of concrete, the nitrilotriacetic acid modified polyurethane and silicone rubber play a synergistic role in the hardening process to improve the compressive strength of the concrete, the nitrilotriacetic acid modified silicone rubber improves the substitution degree of the silicone rubber, and the liquid accelerator has a better compressive effect. The stability is good.

Description

Technical Field

[0001] The invention relates to the technical field of concrete, in particular to a method for preparing an alkali-free, chlorine-free, high-early-strength liquid accelerating setting agent. Background Art

[0002] The alkali-free liquid accelerator in the prior art has the following problems: (1) high dosage, which can only meet the setting time and compressive strength standards of concrete at a high dosage; (2) early strength; (3) poor stability. For example, patent CN102249592A discloses an alkali-free, chlorine-free, high early strength liquid accelerator and its preparation method. The mortar mixed with the product has adjustable setting time, a one-day compressive strength of more than 20 MPa, and a 28-day compressive strength of about 100%. The synthesis process is simple and the reaction conditions are mild. It is a liquid alkali-free accelerator with excellent performance, but its components are relatively simple and its stability is poor. Summary of the invention

[0003] 1. Technical issues to be solved

[0004] In view of the deficiencies in the prior art, the present invention provides a method for preparing an alkali-free, chlorine-free, high-early-strength liquid accelerator, which has the advantages of good stability and high early strength.

[0005] (II) Technical solution

[0006] To achieve the above object, the present invention provides the following technical solution: a method for preparing an alkali-free, chlorine-free, high early strength liquid accelerator, wherein the method for preparing the alkali-free, chlorine-free, high early strength liquid accelerator is as follows:

[0007] (1) Adding purified polyurethane particles to a dimethylformamide solvent, stirring and dissolving at 85-110° C. for 4-7 hours, and then drying to obtain a polyurethane film, further adding methyl methacrylate isothiocyanate, introducing nitrogen for protection, and then adding triethylamine, and oil bathing at 55-70° C. for 6-10 hours. After the reaction, washing with acetonitrile and drying to obtain an olefinic polyurethane;

[0008] (2) adding methanol solvent, inhibitor butylhydroxytoluene, catalyst chloroplatinic acid tetrahydrofuran solution, and divinyl glycol to the reactor, ultrasonically dispersing for 25-40 minutes, then adding silicone rubber, reacting at 55-80° C. for 4-7 hours, cooling to room temperature, centrifuging, and washing to obtain hydroxylated silicone rubber;

[0009] (3) adding nitrilotriacetic acid to toluene solvent, stirring and dispersing, adding hydroxylated silicone rubber thereto, heating to 105-120° C., reacting for 8-14 hours, and after the reaction is completed, performing reduced pressure distillation to obtain nitrilotriacetic acid modified silicone rubber;

[0010] (4) adding nitrilotriacetic acid modified silicone rubber, olefinic polyurethane and acrylic acid to N,N-dimethylformamide solvent, stirring evenly, continuing to add azobisisobutyronitrile initiator, reacting at 75-90° C. for 6-14 hours, and then performing reduced pressure distillation after reaction, filtering and drying to obtain nitrilotriacetic acid modified polyurethane;

[0011] (5) Add magnesium sulfate, diethanolamine, calcium carbonate, nitrilotriacetic acid modified polyurethane and water into a stirrer and stir for 5-15 minutes to obtain an alkali-free and chlorine-free high early strength liquid accelerator.

[0012] Preferably, the mass ratio of the polyurethane particles, the polyurethane film, methacrylate isothiocyanate and triethylamine in (1) is 1:1.2-1.4:0.8-1.4:0.02-0.03.

[0013] Preferably, in (2), the mass ratio of the polymerization inhibitor butylated hydroxytoluene, the catalyst chloroplatinic acid, divinyl glycol, and the silicone rubber is 0.02-0.03:0.01-0.02:1.1-1.3.

[0014] Preferably, the mass ratio of nitrilotriacetic acid to hydroxylated silicone rubber in (3) is 1:2.1-2.6.

[0015] Preferably, the mass ratio of nitrilotriacetic acid modified silicone rubber, olefinic polyurethane, acrylic acid, and azobisisobutyronitrile initiator in (4) is 1:1.1-1.3:0.9-1.2:0.01-0.03.

[0016] Preferably, the mass ratio of magnesium sulfate, diethanolamine, calcium carbonate, nitrilotriacetic acid modified polyurethane and water in (5) is 1.3-1.5:1:0.02-0.04:1.1-1.2:2-3.

[0017] (III) Beneficial technical effects

[0018] The invention comprises the steps of adding magnesium sulfate, diethanolamine, calcium carbonate, nitrilotriacetic acid modified polyurethane and water into a stirrer and stirring to obtain an alkali-free and chlorine-free high early strength liquid accelerating setting agent.

[0019] The polyurethane film is reacted with methyl methacrylate isothiocyanate to introduce alkenyl groups, thereby obtaining alkenyl polyurethane; the alkenyl groups in divinyl glycol and silicone rubber are subjected to addition reaction to introduce a large number of hydroxyl groups, thereby obtaining hydroxylated silicone rubber; nitrilotriacetic acid is reacted with the hydroxyl groups in hydroxylated silicone rubber to obtain nitrilotriacetic acid modified silicone rubber; nitrilotriacetic acid modified silicone rubber, alkenyl polyurethane and acrylic acid are polymerized under the action of azobisisobutyronitrile initiator to obtain nitrilotriacetic acid modified polyurethane.

[0020] The polyurethane in the polyurethane modified by nitrilotriacetic acid can improve the compressive strength of concrete, and synergizes with silicone rubber during the hardening process to improve the compressive strength of concrete. The silicone rubber modified by nitrilotriacetic acid increases the substitution degree of silicone rubber, so that it has better compressive effect. The liquid accelerating setting agent of the invention is alkali-free and chlorine-free and has good stability. DETAILED DESCRIPTION

[0021] Example 1

[0022] (1) Add purified polyurethane particles to dimethylformamide solvent, stir and dissolve at 85° C. for 4 hours, and then dry to obtain a polyurethane film, continue to add methacrylic acid isothiocyanate, introduce nitrogen for protection, and then add triethylamine, wherein the mass ratio of polyurethane particles, polyurethane film, methacrylic acid isothiocyanate, and triethylamine is 1:1.2:0.8:0.02, and oil bath at 55° C. for 6 hours. After the reaction, wash with acetonitrile and dry to obtain olefinic polyurethane;

[0023] (2) adding methanol solvent, inhibitor dibutyl hydroxytoluene, tetrahydrofuran solution of catalyst chloroplatinic acid, and divinyl glycol to a reactor, ultrasonically dispersing for 25 minutes, and then adding silicone rubber, wherein the mass ratio of inhibitor dibutyl hydroxytoluene, catalyst chloroplatinic acid, divinyl glycol, and silicone rubber is 0.02:0.01:1.1, reacting at 55° C. for 4 hours, cooling to room temperature after the reaction, centrifuging, and washing to obtain hydroxylated silicone rubber;

[0024] (3) adding nitrilotriacetic acid to a toluene solvent, stirring and dispersing, and then adding hydroxylated silicone rubber thereto, wherein the mass ratio of nitrilotriacetic acid to hydroxylated silicone rubber is 1:2.1, heating to 105° C., reacting for 8 hours, and after the reaction is completed, performing reduced pressure distillation to obtain nitrilotriacetic acid modified silicone rubber;

[0025] (4) adding nitrilotriacetic acid modified silicone rubber, olefinic polyurethane, and acrylic acid to N,N-dimethylformamide solvent, stirring evenly, and continuing to add azobisisobutyronitrile initiator, wherein the mass ratio of nitrilotriacetic acid modified silicone rubber, olefinic polyurethane, acrylic acid, and azobisisobutyronitrile initiator is 1:1.1:0.9:0.01, reacting at 75° C. for 6 hours, and then distilling under reduced pressure after the reaction, filtering and drying to obtain nitrilotriacetic acid modified polyurethane;

[0026] (5) adding magnesium sulfate, diethanolamine, calcium carbonate, nitrilotriacetic acid modified polyurethane, and water into a stirrer, wherein the mass ratio of magnesium sulfate, diethanolamine, calcium carbonate, nitrilotriacetic acid modified polyurethane, and water is 1.3:1:0.02:1.1:2, and stirring for 5 minutes to obtain an alkali-free and chlorine-free high early strength liquid accelerator.

[0027] Example 2

[0028] (1) Adding purified polyurethane particles to a dimethylformamide solvent, stirring and dissolving at 110° C. for 4-7 hours, and then drying to obtain a polyurethane film, further adding methacrylic acid isothiocyanate, introducing nitrogen for protection, and then adding triethylamine, wherein the mass ratio of the polyurethane particles, the polyurethane film, the methacrylic acid isothiocyanate, and the triethylamine is 1:1.4:1.4:0.03, and the reaction is carried out at 70° C. in an oil bath for 10 hours. After the reaction, washing with acetonitrile and drying are performed to obtain an olefinic polyurethane;

[0029] (2) adding methanol solvent, inhibitor dibutyl hydroxytoluene, tetrahydrofuran solution of catalyst chloroplatinic acid, and divinyl glycol to a reactor, ultrasonically dispersing for 40 minutes, and then adding silicone rubber, wherein the mass ratio of inhibitor dibutyl hydroxytoluene, catalyst chloroplatinic acid, divinyl glycol, and silicone rubber is 0.03:0.02:1.3, reacting at 80° C. for 7 hours, cooling to room temperature after the reaction, centrifuging, and washing to obtain hydroxylated silicone rubber;

[0030] (3) adding nitrilotriacetic acid to toluene solvent, stirring and dispersing, and then adding hydroxylated silicone rubber thereto, wherein the mass ratio of nitrilotriacetic acid to hydroxylated silicone rubber is 1:2.6, heating to 120° C., reacting for 14 hours, and after the reaction is completed, distilling under reduced pressure to obtain nitrilotriacetic acid modified silicone rubber;

[0031] (4) adding nitrilotriacetic acid modified silicone rubber, olefinic polyurethane, and acrylic acid to N,N-dimethylformamide solvent, stirring evenly, and continuing to add azobisisobutyronitrile initiator, wherein the mass ratio of nitrilotriacetic acid modified silicone rubber, olefinic polyurethane, acrylic acid, and azobisisobutyronitrile initiator is 1:1.3:1.2:0.03, reacting at 90° C. for 14 hours, and then distilling under reduced pressure after the reaction, filtering and drying to obtain nitrilotriacetic acid modified polyurethane;

[0032] (5) adding magnesium sulfate, diethanolamine, calcium carbonate, nitrilotriacetic acid modified polyurethane, and water into a stirrer, wherein the mass ratio of magnesium sulfate, diethanolamine, calcium carbonate, nitrilotriacetic acid modified polyurethane, and water is 1.5:1:0.04:1.2:3, and stirring for 15 minutes to obtain an alkali-free and chlorine-free high early strength liquid accelerator.

[0033] Example 3

[0034] (1) Add purified polyurethane particles to dimethylformamide solvent, stir and dissolve at 97° C. for 5 hours, and then dry to obtain a polyurethane film, continue to add methacrylic acid isothiocyanate, introduce nitrogen for protection, and then add triethylamine, wherein the mass ratio of polyurethane particles, polyurethane film, methacrylic acid isothiocyanate, and triethylamine is 1:1.3:1.1:0.025, and oil bath at 62° C. for 8 hours. After the reaction, wash with acetonitrile and dry to obtain olefinic polyurethane;

[0035] (2) adding methanol solvent, inhibitor dibutyl hydroxytoluene, catalyst chloroplatinic acid tetrahydrofuran solution, and divinyl glycol to the reactor, ultrasonically dispersing for 32 minutes, and then adding silicone rubber, wherein the mass ratio of inhibitor dibutyl hydroxytoluene, catalyst chloroplatinic acid, divinyl glycol, and silicone rubber is 0.025:0.015:1.2, reacting at 65° C. for 5 hours, cooling to room temperature after the end, centrifuging, and washing to obtain hydroxylated silicone rubber;

[0036] (3) adding nitrilotriacetic acid to a toluene solvent, stirring and dispersing, and then adding hydroxylated silicone rubber thereto, wherein the mass ratio of nitrilotriacetic acid to hydroxylated silicone rubber is 1:2.3, heating to 112° C., reacting for 11 hours, and after the reaction is completed, performing reduced pressure distillation to obtain nitrilotriacetic acid modified silicone rubber;

[0037] (4) adding nitrilotriacetic acid modified silicone rubber, olefinic polyurethane, and acrylic acid to N,N-dimethylformamide solvent, stirring evenly, and continuing to add azobisisobutyronitrile initiator, wherein the mass ratio of nitrilotriacetic acid modified silicone rubber, olefinic polyurethane, acrylic acid, and azobisisobutyronitrile initiator is 1:1.2:1:0.02, reacting at 82° C. for 10 hours, and then distilling under reduced pressure after the reaction, filtering and drying to obtain nitrilotriacetic acid modified polyurethane;

[0038] (5) adding magnesium sulfate, diethanolamine, calcium carbonate, nitrilotriacetic acid modified polyurethane and water into a stirrer, wherein the mass ratio of magnesium sulfate, diethanolamine, calcium carbonate, nitrilotriacetic acid modified polyurethane and water is 1.4:1:0.03:1.15:2.5, stirring for 10 minutes, and obtaining an alkali-free and chlorine-free high early strength liquid accelerator.

[0039] Example 4

[0040] (1) Add purified polyurethane particles to dimethylformamide solvent, stir and dissolve at 85° C. for 4 hours, and then dry to obtain a polyurethane film, continue to add methacrylic acid isothiocyanate, introduce nitrogen for protection, and then add triethylamine, wherein the mass ratio of polyurethane particles, polyurethane film, methacrylic acid isothiocyanate, and triethylamine is 1:1.2:0.8:0.02, and oil bath at 55° C. for 6 hours. After the reaction, wash with acetonitrile and dry to obtain olefinic polyurethane;

[0041] (2) adding methanol solvent, inhibitor dibutyl hydroxytoluene, tetrahydrofuran solution of catalyst chloroplatinic acid, and divinyl glycol to a reactor, ultrasonically dispersing for 25 minutes, and then adding silicone rubber, wherein the mass ratio of inhibitor dibutyl hydroxytoluene, catalyst chloroplatinic acid, divinyl glycol, and silicone rubber is 0.02:0.01:1.1, reacting at 55° C. for 4 hours, cooling to room temperature after the reaction, centrifuging, and washing to obtain hydroxylated silicone rubber;

[0042] (3) adding nitrilotriacetic acid to toluene solvent, stirring and dispersing, and then adding hydroxylated silicone rubber thereto, wherein the mass ratio of nitrilotriacetic acid to hydroxylated silicone rubber is 1:2.6, heating to 120° C., reacting for 14 hours, and after the reaction is completed, distilling under reduced pressure to obtain nitrilotriacetic acid modified silicone rubber;

[0043] (4) adding nitrilotriacetic acid modified silicone rubber, olefinic polyurethane, and acrylic acid to N,N-dimethylformamide solvent, stirring evenly, and continuing to add azobisisobutyronitrile initiator, wherein the mass ratio of nitrilotriacetic acid modified silicone rubber, olefinic polyurethane, acrylic acid, and azobisisobutyronitrile initiator is 1:1.3:1.2:0.03, reacting at 90° C. for 14 hours, and then distilling under reduced pressure after the reaction, filtering and drying to obtain nitrilotriacetic acid modified polyurethane;

[0044] (5) adding magnesium sulfate, diethanolamine, calcium carbonate, nitrilotriacetic acid modified polyurethane and water into a stirrer, wherein the mass ratio of magnesium sulfate, diethanolamine, calcium carbonate, nitrilotriacetic acid modified polyurethane and water is 1.4:1:0.03:1.15:2.5, stirring for 10 minutes, and obtaining an alkali-free and chlorine-free high early strength liquid accelerator.

[0045] Example 5

[0046] (1) Adding purified polyurethane particles to a dimethylformamide solvent, stirring and dissolving at 110° C. for 4-7 hours, and then drying to obtain a polyurethane film, further adding methacrylic acid isothiocyanate, introducing nitrogen for protection, and then adding triethylamine, wherein the mass ratio of the polyurethane particles, the polyurethane film, the methacrylic acid isothiocyanate, and the triethylamine is 1:1.4:1.4:0.03, and the reaction is carried out at 70° C. in an oil bath for 10 hours. After the reaction, washing with acetonitrile and drying are performed to obtain an olefinic polyurethane;

[0047] (2) adding methanol solvent, inhibitor dibutyl hydroxytoluene, tetrahydrofuran solution of catalyst chloroplatinic acid, and divinyl glycol to a reactor, ultrasonically dispersing for 40 minutes, and then adding silicone rubber, wherein the mass ratio of inhibitor dibutyl hydroxytoluene, catalyst chloroplatinic acid, divinyl glycol, and silicone rubber is 0.03:0.02:1.3, reacting at 80° C. for 7 hours, cooling to room temperature after the reaction, centrifuging, and washing to obtain hydroxylated silicone rubber;

[0048] (3) adding nitrilotriacetic acid to a toluene solvent, stirring and dispersing, and then adding hydroxylated silicone rubber thereto, wherein the mass ratio of nitrilotriacetic acid to hydroxylated silicone rubber is 1:2.3, heating to 112° C., reacting for 11 hours, and after the reaction is completed, performing reduced pressure distillation to obtain nitrilotriacetic acid modified silicone rubber;

[0049] (4) adding nitrilotriacetic acid modified silicone rubber, olefinic polyurethane, and acrylic acid to N,N-dimethylformamide solvent, stirring evenly, and continuing to add azobisisobutyronitrile initiator, wherein the mass ratio of nitrilotriacetic acid modified silicone rubber, olefinic polyurethane, acrylic acid, and azobisisobutyronitrile initiator is 1:1.2:1:0.02, reacting at 82° C. for 10 hours, and then distilling under reduced pressure after the reaction, filtering and drying to obtain nitrilotriacetic acid modified polyurethane;

[0050] (5) adding magnesium sulfate, diethanolamine, calcium carbonate, nitrilotriacetic acid modified polyurethane, and water into a stirrer, wherein the mass ratio of magnesium sulfate, diethanolamine, calcium carbonate, nitrilotriacetic acid modified polyurethane, and water is 1.3:1:0.02:1.1:2, and stirring for 5 minutes to obtain an alkali-free and chlorine-free high early strength liquid accelerator.

[0051] Comparative Example 1

[0052] The difference between this comparative example and Example 5 is that no nitrilotriacetic acid is added to modify the polyurethane.

[0053] The alkali-free and chlorine-free high early strength liquid accelerators obtained in Examples 1-5 and Comparative Example 1 were formulated into cement mortar for performance measurement. The compressive strength of the cement mortar mixed with the accelerator was measured according to the measurement method in GB / T35159-2017 Accelerators for Shotcrete. The test results are shown in Table 1.

[0054] Table 1: Compressive strength test.

[0055] project 6h compressive strength (Mpa) 1d compressive strength(Mpa) Example 1 2.34 14.3 Example 2 2.17 15.8 Example 3 2.56 14.6 Example 4 2.47 15.1 Example 5 2.39 15.3 Comparative Example 1 1.82 10.4

[0056] It can be seen from Table 1 that Examples 1-5 of the present invention have better compressive strength than Comparative Example 1.

[0057] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing an alkali-free, chlorine-free, high early-strength liquid accelerator, characterized in that: The preparation method of the alkali-free and chlorine-free high early strength liquid accelerator is as follows: (1) Adding purified polyurethane particles to a dimethylformamide solvent, stirring and dissolving at 85-110° C. for 4-7 hours, and then drying to obtain a polyurethane film, further adding methyl methacrylate isothiocyanate, introducing nitrogen for protection, and then adding triethylamine, and oil bathing at 55-70° C. for 6-10 hours. After the reaction, washing with acetonitrile and drying to obtain an olefinic polyurethane; (2) adding methanol solvent, inhibitor butylhydroxytoluene, catalyst chloroplatinic acid tetrahydrofuran solution, and divinyl glycol to the reactor, ultrasonically dispersing for 25-40 minutes, then adding silicone rubber, reacting at 55-80° C. for 4-7 hours, cooling to room temperature, centrifuging, and washing to obtain hydroxylated silicone rubber; (3) adding nitrilotriacetic acid to toluene solvent, stirring and dispersing, adding hydroxylated silicone rubber thereto, heating to 105-120° C., reacting for 8-14 hours, and after the reaction is completed, performing reduced pressure distillation to obtain nitrilotriacetic acid modified silicone rubber; (4) adding nitrilotriacetic acid modified silicone rubber, olefinic polyurethane and acrylic acid to N,N-dimethylformamide solvent, stirring evenly, continuing to add azobisisobutyronitrile initiator, reacting at 75-90° C. for 6-14 hours, and then performing reduced pressure distillation after reaction, filtering and drying to obtain nitrilotriacetic acid modified polyurethane; (5) Add magnesium sulfate, diethanolamine, calcium carbonate, nitrilotriacetic acid modified polyurethane and water into a stirrer and stir for 5-15 minutes to obtain an alkali-free and chlorine-free high early strength liquid accelerator.

2. The method for preparing the alkali-free, chlorine-free, high early strength liquid accelerating setting agent according to claim 1, characterized in that: The mass ratio of the polyurethane particles, the polyurethane film, methacrylate isothiocyanate and triethylamine in (1) is 1:1.2-1.4:0.8-1.4:0.02-0.

03.

3. The method for preparing the alkali-free, chlorine-free, high early strength liquid accelerator according to claim 1, characterized in that: The mass ratio of the polymerization inhibitor dibutyl hydroxytoluene, the catalyst chloroplatinic acid, divinyl glycol and the silicone rubber in (2) is 0.02-0.03:0.01-0.02:1.1-1.

3.

4. The method for preparing the alkali-free, chlorine-free, high early strength liquid accelerating setting agent according to claim 1, characterized in that: The mass ratio of nitrilotriacetic acid to hydroxylated silicone rubber in (3) is 1:2.1-2.

6.

5. The method for preparing the alkali-free, chlorine-free, high early strength liquid accelerating setting agent according to claim 1, characterized in that: The mass ratio of nitrilotriacetic acid modified silicone rubber, olefinic polyurethane, acrylic acid and azobisisobutyronitrile initiator in (4) is 1:1.1-1.3:0.9-1.2:0.01-0.

03.

6. The method for preparing the alkali-free, chlorine-free, high early strength liquid accelerating setting agent according to claim 1, characterized in that: The mass ratio of magnesium sulfate, diethanolamine, calcium carbonate, nitrilotriacetic acid modified polyurethane and water in (5) is 1.3-1.5:1:0.02-0.04:1.1-1.2:2-3.