A strong slump retention and water reducing aid, its preparation method and application

Abstract

The present invention discloses a strong slump retention and water reducing aid, its preparation method and application, which has the structure shown in Formula 1: The water reducing aid of the present invention starts with astaxanthin, first polymerizes with a small amount of PO under the condition of an alkaline earth metal catalyst and then polymerizes with a large amount of EO. The product has high adaptability and has good adaptability to the synthesis temperatures of different water reducing agent mother liquors. The product has strong slump retention property. Adding a small amount to ordinary water reducing agents can significantly improve the slump retention property of commercially available water reducing agents by 2 times or more. At the same time, due to the special structure of the catalyst, the product has low foaming, avoiding foaming during the synthesis of the mother liquor, and is mainly used in the fields of concrete and construction.

Description

Technical Field

[0001] The present invention belongs to the technical field of water reducing agents, and relates to a strong slump retention water reducing aid, a preparation method thereof and an application thereof. Background Art

[0002] In the fields of construction and concrete, after concrete is stirred, it needs to maintain fluidity and slump within a certain period of time. However, a large amount of water cannot be added to the concrete because it takes a long time for the water to evaporate until the concrete solidifies, and too much water will reduce the solid content and the strength of the concrete will deteriorate. Therefore, the use of water reducing agents is particularly important for the water reducing agent industry.

[0003] With the development of the economic society, the polyether macromonomers used in the synthesis of polycarboxylate water reducing agents in China have developed from the initial MPEG (methoxypolyethylene glycol) to the current APEG (allyl polyoxyethylene ether), TPEG (isopentenyl polyoxyethylene ether) and HPEG (methallyl polyoxyethylene ether). Among them, TPEG and HPEG macromonomers have occupied the largest market share in China.

[0004] According to the paper "Brief Analysis of the Process Technology of Polyether Macromonomers for Polycarboxylate Water Reducing Agents" published by Wang Yexiang and Wang Wenjuan in "Chemical Industry Management" in 2018:

[0005] When synthesizing water reducing agents with MPEG, generally two steps of polymerization and esterification are involved. And because MPEG cannot be completely esterified, the MPEG remaining in the product will greatly affect the application performance of the water reducing agent and cause unstable product quality.

[0006] When synthesizing water reducing agents with APEG, it can be prepared only by polymerizing it with the initiator monomer solution. However, the polymerization activity of APEG is poor, and the residual amount is similar to that of MPEG monomer, and the performance of the obtained water reducing agent is unstable. At present, the output decreases year by year.

[0007] The synthesis of water reducing agents with TPEG and HPEG has become the mainstream variety in the domestic market. They have good polymerization activity and good water reducing rate, but their slump retention performance needs to be improved.

[0008] According to Dr. Liu Guanjie of Shanxi University in "Study on the Conditions and Performance of Synthesizing Polycarboxylate Water Reducing Agents with Vinyl Ether Macromonomer EPEG" and "Research Progress on the Application of Polyether Macromonomers for Polycarboxylate Water Reducing Agents", when synthesizing the mother liquor of water reducing agent products on the market at present, there are still generally the following problems: ① relatively strict temperature control is required, and temperature fluctuations have a greater impact on product performance. The mother liquor synthesis temperature of APEG and MPEG is 60°C - 70°C, TPEG and HPEG usually require 40°C - 50°C, and the new water reducing agent EPEG in the past two years needs to be cooled to 5°C - 15°C for mother liquor synthesis. ② There are more foams when synthesizing the mother liquor, and additional defoamers need to be added. Summary of the Invention

[0009] In view of the above problems existing in the prior art, the present invention provides a water-reducing aid and a preparation method thereof. A water-reducing aid is prepared by polymerizing propylene oxide (PO) and ethylene oxide (EO) using astaxanthin as an initiator. This aid has low temperature requirements and high adaptability, and has good adaptability to the synthesis temperatures of different water-reducing agent mother liquors. The product has strong slump retention performance. Adding a small amount can significantly improve the slump retention of commercially available ordinary water-reducing agents by 2 times or more. Moreover, the product has low foam, avoiding foaming during the synthesis of the mother liquor and eliminating the need for additional defoaming agents.

[0010] The above water-reducing aid of the present invention can be widely applied to the fields of construction and concrete.

[0011] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0012] The present invention provides a water-reducing aid having a structure as shown in Formula 1:

[0013]

[0014] In the formula, m independently takes values of 1 - 5, preferably 1 - 3; n independently takes values of 40 - 140, preferably 50 - 80.

[0015] The present invention also provides a preparation method of the water-reducing aid shown in Formula 1. In a nitrogen environment, using astaxanthin as an initiator and adding an alkaline earth metal catalyst, first reacting with propylene oxide and then reacting with ethylene oxide to obtain the water-reducing aid shown in Formula 1.

[0016] In the present invention, the structure of the alkaline earth metal catalyst is: Wherein R represents an alkyl group of C6 - C16, preferably n-hexyl, isooctyl, isodecyl, isoundecyl, isotridecyl, hexadecyl, more preferably n-hexyl, isodecyl, isotridecyl; M represents an alkaline earth metal element, preferably calcium, magnesium, barium, more preferably calcium, magnesium; p takes a value of 1 - 30, preferably 2 - 10.

[0017] In some examples, the preparation method of the alkaline earth metal catalyst in the present invention is: in a nitrogen environment, under the condition of an alkaline catalyst, an alcohol of C6 - C16 reacts with propylene oxide, and then chloroacetic acid is added for reaction to obtain the alkaline earth metal catalyst;

[0018] Among them, the alkaline catalyst is selected from one or more of calcium hydroxide, barium hydroxide, and magnesium hydroxide;

[0019] The alcohol of C6 - C16 is preferably n-hexanol, isooctanol, isodecanol, isoundecanol, isotridecanol, hexadecanol, more preferably n-hexanol, isodecanol, isotridecanol;

[0020] Among them, the mass ratio of the C6-C16 alcohol to the alkaline catalyst is 1:0.24-1.99, preferably 1:0.29-1.56;

[0021] The mass ratio of the C6-C16 alcohol to propylene oxide is 1:0.2-17.1, preferably 1:1.2-10.0;

[0022] The mass ratio of the C6-C16 alcohol to chloroacetic acid is 1:0.7-1.85, preferably 1:0.8-1.5;

[0023] Among them, the reaction temperature of the C6-C16 alcohol with propylene oxide is 80-130 °C, preferably 100-130 °C, the pressure is 0.1-0.6 MPaG, preferably 0.1-0.3 MpaG, and the time is 0.5-2 h, preferably 1-2 h;

[0024] Preferably, the propylene oxide is fed continuously, the pressure during the feeding process is controlled at 0.1-0.6 MPaG, preferably 0.1-0.3 MpaG, the feeding time is 0.5-5 h, preferably 0.5-3 h, and the feeding time is not included in the above reaction time;

[0025] Then the temperature for continuous reaction with chloroacetic acid is 50-100 °C, preferably 60-80 °C, the pressure is 0-0.1 MPaG, preferably 0-0.05 MpaG, and the time is 1-3 h, preferably 1-2 h.

[0026] In the present invention, the dosage of the alkaline earth metal catalyst is 0.35-11.3% of the mass of astaxanthin, preferably 0.5-10%.

[0027] In the present invention, the astaxanthin has a water content of less than 200 ppm, preferably less than 100 ppm.

[0028] In the present invention, the mass ratio of astaxanthin to propylene oxide is 1:0.19-0.98, preferably 1:0.19-0.59;

[0029] The mass ratio of astaxanthin to ethylene oxide is 1:5.8-20.7, preferably 1:7.3-11.8.

[0030] In the present invention, for the reaction with propylene oxide, the temperature is 120-180 °C, preferably 130-160 °C, and the time is 1-3 h, preferably 1-2 h;

[0031] For the reaction with ethylene oxide, the temperature is 80-180 °C, preferably 100-120 °C, and the time is 0.5-3 h, preferably 1-2 h;

[0032] Preferably, the reaction (PO and EO segments) process uses a batch reactor;

[0033] Preferably, the propylene oxide feeding time is controlled to be 0.5 - 1.5 h, preferably 1 h, the pressure in the reaction kettle is controlled ≤ 0.6 MPaG, and the stirring is not started during the PO feeding. After the feeding is completed, the stirring is started to initiate the reaction. The feeding time is not included in the reaction time defined in the above PO segment;

[0034] Preferably, the ethylene oxide is fed continuously. The pressure during the feeding process is controlled to be 0.1 - 0.6 MPaG, preferably 0.1 - 0.3 MPaG, and the feeding time is 4 - 18 h, preferably 6 - 10 h. The feeding time is not included in the reaction time defined in the above EO segment.

[0035] In the initial stage of the preparation of the water-reducing aid in the present invention, the stirring is not carried out during the PO feeding. After a small amount of the branched chains of PO reduce the freezing point of astaxanthin, the stirring is started to ensure the smooth progress of the subsequent reaction. At the same time, the grafting amount of PO is strictly controlled, which can improve the product performance.

[0036] The water-reducing aid shown in Formula 1 of the present invention further includes formulating a water-reducing aid composition by adding an antioxidant;

[0037] Specifically, in the preparation method of the water-reducing aid, after the reaction is completed, an antioxidant is added to the reaction solution to obtain a water-reducing aid composition;

[0038] Preferably, the antioxidant is a mixture of BHT and 618, and the mass ratio of the two is 1:0.9 - 1.1, preferably 1:1;

[0039] The addition amount of the antioxidant in the reaction solution is 10 - 200 ppm, preferably 10 - 100 ppm.

[0040] The water-reducing aid of the present invention has the characteristics of high adaptability, strong slump retention, low foaming, and low addition amount, and can be widely applied to the fields of construction and concrete, especially suitable for application in the concrete field.

[0041] In the present invention, the water-reducing aid is used in combination with a water reducer, and its dosage is 0.01 - 0.5 wt% of the mass of the water reducer, preferably 0.02 - 0.2 wt%;

[0042] The water-reducing aid can be the water-reducing aid shown in Formula 1, or the water-reducing aid composition after adding an antioxidant;

[0043] The water-reducing agent category is selected from methallyl alcohol polyoxyethylene ether, isopentenol polyoxyethylene ether, vinyl polyoxyethylene ether, preferably methallyl alcohol polyoxyethylene ether, isopentenol polyoxyethylene ether, such as OKchem 608 / 702 (methallyl alcohol polyoxyethylene ether), OKchem 501 / 703 (isopentenol polyoxyethylene ether).

[0044] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0045] The present invention uses astaxanthin as the initiator. Due to the unique multi-double bond structure of astaxanthin, it is easy to polymerize with acrylic acid into macromolecules when synthesizing the mother liquor. Moreover, its reaction process has high adaptability and a wide reaction temperature range. And adding a small amount of it into ordinary water-reducing agents can significantly improve the slump retention of commercially available water-reducing agents by 2 times or more. And due to the multi-branched special structure of the alkaline earth metal catalyst introduced in the preparation process, the product has low foam, avoiding foaming during the synthesis of the mother liquor. Detailed implementation manners

[0046] The present invention will be further described below through specific examples, but the present invention is not limited to the following examples.

[0047] The information on the sources of the main raw materials used in the examples of the present invention are all ordinary commercially available raw materials unless otherwise specified:

[0048] EO: Wanhua Chemical, water content < 100 ppm;

[0049] PO: Wanhua Chemical, water content < 100 ppm;

[0050] Astaxanthin: Wuhan Xinru Chemical Co., Ltd., water content ≤ 200 ppm;

[0051] Sodium hydroxide: Sinopharm Reagent, purity ≥ 99%;

[0052] L-Ascorbic acid: Sinopharm Reagent, purity ≥ 99%;

[0053] Acrylic acid: Beijing Chemical Factory, purity ≥ 99%;

[0054] Hydrogen peroxide: Luoyang Chemical Reagent Factory, purity 30%;

[0055] Mercaptoacetic acid: Nanjing Guochen, purity ≥ 99%;

[0056] Antioxidant: BHT is purchased from Shanghai Feige Chemical Co., Ltd., and 618 is purchased from Nanjing Milan New Materials Co., Ltd.

[0057] The main test methods used in the examples of the present invention:

[0058] Molecular weight: GPC is measured according to GB / T 21863-2008 to characterize the molecular weight.

[0059] Double bond retention rate: The iodine value is determined according to GB / T 13892-2020 to characterize the double bond retention rate of the product.

[0060] Content of by-product polyethylene glycol (PEG): The content of polyethylene glycol in the product is determined according to GB / T 16086-1995.

[0061] Compound characterization method: DMSO is used as the solvent, and 400 MHz nuclear magnetic carbon spectrum is used for structural analysis.

[0062] Example 1

[0063] Preparation of alkaline earth metal catalyst A:

[0064] 86 g of n-hexane and 21.5 g of calcium hydroxide are added to the reaction vessel. After purging with nitrogen at room temperature, the temperature is raised to 100 °C. 116 g of propylene oxide is introduced into the reaction kettle. The feeding time of propylene oxide is 0.5 h, and the pressure of the reaction kettle is controlled at 0.1-0.3 MPaG. After the feeding of propylene oxide is completed, the reaction continues for 1 h. Then the temperature is lowered to 80 °C, 60.2 g of chloroacetic acid is added, and the reaction is stirred at 0-0.1 MPaG for 1 h. The obtained product is alkaline earth metal catalyst A. In the structural formula, R is n-hexyl, M is Ca, and p is 2;

[0065] Characterization: The chemical structure of the prepared product is characterized by NMR (Varian INOVA 400 MHz), 13 C NMR (400 MHz, DMSO-d6): δ = 14.1 ppm (S, 2C, CH3), 22.7 ppm (S, 2C, CH2), 31.8 ppm (S, 2C, CH2), 22.6 ppm (S, 2C, CH2), 30.0 ppm (S, 2C, CH2), 71.0 ppm (S, 2C, CH2), 78.2 ppm (S, 2C, CH2), 78.1 ppm (S, 2C, CH), 17.6 ppm (S, 2C, CH3), 75.4 ppm (S, 2C, CH2), 77.5 ppm (S, 2C, CH), 17.3 ppm (S, 2C, CH), 68.4 ppm (S, 2C, CH2), 175.4 ppm (S, 2C, C).

[0066] Preparation of water-reducing aid A:

[0067] Add 597 g of astaxanthin and 2.1 g of alkaline earth metal catalyst A to the reaction vessel. After purging with nitrogen, heat up to 160 °C. At this time, do not start stirring. Introduce 113.5 g of propylene oxide into the reaction kettle. The feeding time of propylene oxide is 1 h, and control the pressure in the reaction kettle ≤ 0.6 MPaG. After the feeding of propylene oxide is completed, start stirring and continue the reaction at 160 °C for 2 h. Then, at 120 °C, continue to add 3463 g of ethylene oxide to the reaction kettle. The feeding time is 6 h, and during this period, control the pressure to be 0.1 - 0.3 MPaG. After the feeding of ethylene oxide is completed, continue the reaction for 1 h to obtain the water-reducing agent shown in Formula 1. In the structural formula, m takes the value of 1 and n takes the value of 40. The molecular weight distribution was examined by GPC, showing that its molecular weight is about 4100 g / mol. Iodine value titration shows that the double bond retention rate is 99.8%, and the PEG content detection is 0.1%.

[0068] Characterization: NMR (Varian INOVA 400 MHz) was used to characterize the chemical structure of the prepared product, 13 C NMR (400 MHz, DMSO-d6): δ = 17.1 ppm (S, 2C, CH3), 63.7 ppm (S, 2C, CH2), 73.1 ppm (S, 2C, CH2), 71.2 ppm (S, 78C, CH2), 68.4 ppm (S, 78C, CH2), 75.1 ppm (S, 2C, CH2), 72.6 ppm (S, 2C, CH2), 85 ppm (S, 2C, CH), 197.6 ppm (S, 2C, C), 125.2 ppm (S, 2C, CH), 38.6 ppm (S, 2C, CH2), 27.1 ppm (S, 2C, C), 25.1 ppm (S, 8C, CH3), 160.2 ppm (S, 2C, C), 129.9 ppm (S, 10C, CH), 139.3 ppm (S, 4C, C), 17.3 ppm (S, 4C, CH3), 122.5 ppm (S, 4C, C).

[0069] Then, add a mixed antioxidant with a concentration of 10 ppm (BHT and 618 are mixed at a mass ratio of 1:1) to the above reaction solution at 80 °C. After stirring for 30 min, a water-reducing agent composition is obtained. The application performance test results are shown in Table 1.

[0070] Example 2

[0071] Preparation of alkaline earth metal catalyst B:

[0072] Add 185 g of isomeric decanol and 50 g of magnesium hydroxide to the reaction vessel. After purging with nitrogen at room temperature, heat up to 120 °C. Feed 1740 g of propylene oxide into the reaction kettle. The feeding time of propylene oxide is 5 h. Control the pressure in the reaction kettle at 0.1 - 0.3 MPaG. After the feeding of propylene oxide is completed, continue the aging reaction for 2 h. Then cool down to 60 °C and add 342 g of chloroacetic acid. Stir and react for 1 h under 0 - 0.1 MPaG. The obtained product is alkaline earth metal catalyst B. In the structural formula, R is isomeric decyl, M is Mg, and p takes the value of 30;

[0073] Characterization: NMR (Varian INOVA 400 MHz) was used to characterize the chemical structure of the prepared product, 13 C NMR (400 MHz, DMSO-d6): δ = 14.1 ppm (S, 2C, CH3), 14.4 ppm (S, 2C, CH3), 22.7 ppm (S, 2C, CH2), 32.1 ppm (S, 2C, CH2), 27.1 ppm (S, 2C, CH2), 31.5 ppm (S, 2C, CH2), 38.2 ppm (S, 2C, CH), 33.7 ppm (S, 2C, CH2), 20.5 ppm (S, 2C, CH2), 78.8 ppm (S, 2C, CH2), 78.5 ppm (S, 2C, CH2), 78.1 ppm (S, 2C, CH), 17.6 ppm (S, 58C, CH3), 75.7 ppm (S, 56C, CH2), 78.4 ppm (S, 56C, CH), 77.5 ppm (S, 2C, CH), 75.4 ppm (S, 2C, CH2), 17.3 ppm (S, 2C, CH3), 68.4 ppm (S, 2C, CH2), 175.4 ppm (S, 2C, C).

[0074] Preparation of water-reducing agent B:

[0075] Add 597 g of astaxanthin and 67.4 g of alkaline earth metal catalyst B to the reaction vessel. After purging with nitrogen, heat up to 120 °C. At this time, do not start stirring. Feed 585 g of propylene oxide into the reaction kettle. The feeding time of propylene oxide is 1 h. Control the pressure in the reaction kettle ≤ 0.6 MPaG. After the feeding of propylene oxide is completed, start stirring and continue the reaction at 120 °C for 1 h. Continue to add 12357 g of ethylene oxide to the reaction kettle at 80 °C. The feeding time is 18 h. During this period, control the pressure at 0.1 - 0.3 MPaG. After the feeding of ethylene oxide is completed, continue the reaction for 1 h to obtain the water-reducing agent shown in Formula 1. In the structural formula, m takes the value of 5 and n takes the value of 140. GPC was used to check the molecular weight distribution, showing that its molecular weight is about 13000 g / mol. Iodine value titration shows that the double bond retention rate is 99.7%, and the PEG content detection is 0.2%.

[0076] Characterization: The chemical structure of the prepared product was characterized by NMR (Varian INOVA 400 MHz). 13 C NMR (400 MHz, DMSO-d6): δ = 17.1 ppm (S, 10C, CH3), 63.7 ppm (S, 2C, CH2), 73.1 ppm (S, 2C, CH2), 71.2 ppm (S, 278C, CH2), 68.4 ppm (S, 278C, CH2), 75.1 ppm (S, 10C, CH2), 72.6 ppm (S, 10C, CH2), 85 ppm (S, 2C, CH), 197.6 ppm (S, 2C, C), 125.2 ppm (S, 2C, CH), 38.6 ppm (S, 2C, CH2), 27.1 ppm (S, 2C, C), 25.1 ppm (S, 8C, CH3), 160.2 ppm (S, 2C, C), 129.9 ppm (S, 10C, CH), 139.3 ppm (S, 4C, C), 17.3 ppm (S, 4C, C), 122.5 ppm (S, 4C, C).

[0077] Then, a mixed antioxidant with a concentration of 20 ppm (a 1:1 mass ratio mixture of BHT and 618) was added to the above reaction solution at 80°C. After stirring for 30 min, a water-reducing aid composition was obtained. The results of the application performance test are shown in Table 1.

[0078] Example 3

[0079] Preparation of alkaline earth metal catalyst C:

[0080] 200 g of isomeric tridecanol and 312 g of barium hydroxide were added to a reaction vessel. After purging with nitrogen at room temperature, the temperature was raised to 130°C. 580 g of propylene oxide was introduced into the reaction kettle, and the feeding time of propylene oxide was 8 h. The pressure in the reaction kettle was controlled at 0.1 - 0.3 MPaG. After the feeding of propylene oxide was completed, the aging reaction was continued for 2 h. Then, the temperature was lowered to 50°C, and 200 g of chloroacetic acid was added. The reaction was stirred at 0 - 0.05 MPaG for 1 h. The obtained product was alkaline earth metal catalyst C. In the structural formula, R is isomeric tridecyl, M is Ba, and p is 10.

[0081] Characterization: The chemical structure of the prepared product was characterized by NMR (Varian INOVA 400 MHz). 1313C NMR (400 MHz, DMSO-d6): δ = 23.2 ppm (s, 4C, CH3), 28.1 ppm (s, 2C, CH), 39.6 ppm (s, 2C, CH2), 26.8 ppm (s, 2C, CH2), 30.0 ppm (s, 2C, CH2), 71.0 ppm (s, 2C, CH2), 29.2 ppm (s, 2C, CH2), 29.9 ppm (s, 2C, CH2), 29.6 ppm (s, 8C, CH2), 78.2 ppm (s, 2C, CH2), 78.1 ppm (s, 2C, CH), 17.6 ppm (s, 18C, CH3), 75.7 ppm (s, 16C, CH2), 78.4 ppm (s, 16C, CH), 77.5 ppm (s, 2C, CH), 75.4 ppm (s, 2C, CH2), 17.3 ppm (s, 2C, CH3), 68.4 ppm (s, 2C, CH2), 175.4 ppm (s, 2C, C).

[0082] Preparation of water-reducing auxiliary C:

[0083] Add 597 g of astaxanthin and 11.9 g of alkaline earth metal catalyst C to the reaction vessel. After purging with nitrogen, heat up to 140 °C. At this time, do not start stirring. Introduce 352 g of propylene oxide into the reaction kettle. The feeding time of propylene oxide is 1 h. Control the pressure in the reaction kettle ≤ 0.6 MPaG. After the feeding of propylene oxide is completed, start stirring and continue to react at 140 °C for 1.5 h. Heat up to 180 °C and continue to add 7044 g of ethylene oxide to the reaction kettle. The feeding time is 8 h. During this period, control the pressure at 0.1 - 0.3 MPaG. After the feeding of ethylene oxide is completed, continue to react for 1 h to obtain the water-reducing auxiliary shown in Formula 1. In the structural formula, m takes the value of 3 and n takes the value of 80. GPC is used to check the molecular weight distribution, and it shows that its molecular weight is about 13,000 g / mol. Iodine value titration shows that the double bond retention rate is 99.5%, and the PEG content detection is 0.3%.

[0084] Characterization: NMR (Varian INOVA 400 MHz) is used to characterize the chemical structure of the prepared product, 1313C NMR (400 MHz, DMSO-d6): δ = 17.1 ppm (s, 6C, CH3), 63.7 ppm (s, 2C, CH2), 73.1 ppm (s, 2C, CH2), 71.2 ppm (s, 158C, CH2), 68.4 ppm (s, 158C, CH2), 75.1 ppm (s, 6C, CH2), 72.6 ppm (s, 6C, CH2), 85 ppm (s, 2C, CH), 197.6 ppm (s, 2C, C), 125.2 ppm (s, 2C, CH), 38.6 ppm (s, 2C, CH2), 27.1 ppm (s, 2C, C), 25.1 ppm (s, 8C, CH3), 160.2 ppm (s, 2C, C), 129.9 ppm (s, 10C, CH), 139.3 ppm (s, 4C, C), 17.3 ppm (s, 4C, C), 122.5 ppm (s, 4C, C).

[0085] Then, 100 ppm of a mixed antioxidant (a 1:1 mass ratio mixture of BHT and 618) was added to the above reaction solution at 80 °C. After stirring for 30 min, a water-reducing aid composition was obtained. The results of the application performance test are shown in Table 1.

[0086] Example 4

[0087] Preparation of alkaline earth metal catalyst D:

[0088] 242 g of hexadecanol and 70.2 g of calcium hydroxide were added to a reaction vessel. After purging with nitrogen at room temperature, the temperature was raised to 80 °C. 290 g of propylene oxide was introduced into the reaction kettle, and the feeding time of propylene oxide was 1 h. The pressure in the reaction kettle was controlled at 0.1 - 0.3 MPaG. After the feeding of propylene oxide was completed, the aging reaction was continued for 1 h. Then the temperature was raised to 100 °C, and 193 g of chloroacetic acid was added. The reaction was stirred at 0 - 0.05 MPaG for 1 h. The obtained product was alkaline earth metal catalyst D. In the structural formula, R is hexadecyl, M is Ca, and p is 5;

[0089] Characterization: NMR (Varian INOVA 400 MHz) was used to characterize the chemical structure of the prepared product, 1313C NMR (400 MHz, DMSO-d6): δ = 14.1 ppm (s, 2C, CH3), 22.7 ppm (s, 2C, CH), 31.9 ppm (s, 2C, CH2), 29.3 ppm (s, 2C, CH2), 29.6 ppm (s, 18C, CH2), 29.2 ppm (s, 2C, CH2), 30.0 ppm (s, 2C, CH2), 71.0 ppm (s, 2C, CH2), 78.2 ppm (s, 2C, CH2), 78.1 ppm (s, 2C, CH), 17.6 ppm (s, 8C, CH3), 75.7 ppm (s, 6C, CH2), 78.4 ppm (s, 16C, CH), 77.5 ppm (s, 2C, CH), 75.4 ppm (s, 2C, CH2), 17.3 ppm (s, 2C, CH3), 68.4 ppm (s, 2C, CH2), 175.4 ppm (s, 2C, C).

[0090] Preparation of water-reducing aid D:

[0091] Add 597 g of astaxanthin and 6 g of alkaline earth metal catalyst D to the reaction vessel. After purging with nitrogen, heat up to 180 °C. At this time, do not start stirring. Feed 232 g of propylene oxide into the reaction kettle. The feeding time of propylene oxide is 1 h, and control the pressure in the reaction kettle ≤ 0.6 MPaG. After the feeding of propylene oxide is completed, start stirring and continue to react at 180 °C for 1 h. Cool down to 100 °C and continue to add 4360 g of ethylene oxide into the reaction kettle. The feeding time is 10 h. During this period, control the pressure at 0.1 - 0.3 MPaG. After the feeding of ethylene oxide is completed, continue to react for 2 h to obtain the water-reducing aid shown in Formula 1. In the structural formula, m takes the value of 2 and n takes the value of 50. GPC shows that the molecular weight distribution is around 5000 g / mol. Iodine value titration shows that the double bond retention rate is 99.8%, and the PEG content detection is 0.4%.

[0092] Characterization: NMR (Varian INOVA 400 MHz) was used to characterize the chemical structure of the prepared product. 1313C NMR (400 MHz, DMSO-d6): δ = 17.1 ppm (s, 4C, CH3), 63.7 ppm (s, 2C, CH2), 73.1 ppm (s, 2C, CH2), 71.2 ppm (s, 98C, CH2), 68.4 ppm (s, 98C, CH2), 75.1 ppm (s, 4C, CH2), 72.6 ppm (s, 4C, CH2), 85 ppm (s, 2C, CH), 197.6 ppm (s, 2C, C), 125.2 ppm (s, 2C, CH), 38.6 ppm (s, 2C, CH2), 27.1 ppm (s, 2C, C), 25.1 ppm (s, 8C, CH3), 160.2 ppm (s, 2C, C), 129.9 ppm (s, 10C, CH), 139.3 ppm (s, 4C, C), 17.3 ppm (s, 4C, C), 122.5 ppm (s, 4C, C).

[0093] Then, 200 ppm of a mixed antioxidant (a 1:1 mass ratio mixture of BHT and 618) was added to the above reaction solution at 80 °C. After stirring for 30 min, a water-reducing aid composition was obtained. The results of the application performance test are shown in Table 1.

[0094] Example 5

[0095] Preparation of alkaline earth metal catalyst E:

[0096] 172 g of isomeric undecanol and 74 g of calcium hydroxide were added to a reaction vessel. After purging with nitrogen at room temperature, the temperature was raised to 130 °C. 464 g of propylene oxide was introduced into the reaction kettle. The feeding time of propylene oxide was 5 h, and the pressure in the reaction kettle was controlled at 0.1 - 0.3 MPaG. After the feeding of propylene oxide was completed, the aging reaction was continued for 2 h. Then, the temperature was lowered to 80 °C, and 200 g of chloroacetic acid was added. The reaction was stirred at 0 - 0.1 MPaG for 1 h. The resulting product was alkaline earth metal catalyst C. In the structural formula, R is an isomeric undecyl group, M is Ca, and p has a value of 8;

[0097] Characterization: NMR (Varian INOVA 400 MHz) was used to characterize the chemical structure of the prepared product, 1313C NMR (400 MHz, DMSO-d6): δ = 23.2 ppm (s, 4C, CH3), 28.1 ppm (s, 2C, CH), 39.6 ppm (s, 2C, CH2), 26.8 ppm (s, 2C, CH2), 30.0 ppm (s, 2C, CH2), 71.0 ppm (s, 2C, CH2), 29.2 ppm (s, 2C, CH2), 29.9 ppm (s, 2C, CH2), 29.6 ppm (s, 6C, CH2), 78.2 ppm (s, 2C, CH2), 78.1 ppm (s, 2C, CH), 17.6 ppm (s, 14C, CH3), 75.7 ppm (s, 12C, CH2), 78.4 ppm (s, 12C, CH), 77.5 ppm (s, 2C, CH), 75.4 ppm (s, 2C, CH2), 17.3 ppm (s, 2C, CH3), 68.4 ppm (s, 2C, CH2), 175.4 ppm (s, 2C, C).

[0098] Preparation of water-reducing aid E:

[0099] Add 597 g of astaxanthin and 17 g of alkaline earth metal catalyst E to the reaction vessel. After purging with nitrogen, heat up to 150 °C. At this time, do not start stirring. Introduce 232 g of propylene oxide into the reaction kettle. The feeding time of propylene oxide is 1 h. Control the pressure in the reaction kettle ≤ 0.6 MPaG. After the feeding of propylene oxide is completed, start stirring and continue to react at 150 °C for 1 h. At 150 °C, continue to add 5373 g of ethylene oxide to the reaction kettle. The feeding time is 4 h. During this period, control the pressure to be 0.1 - 0.3 MPaG. After the feeding of ethylene oxide is completed, continue to react for 2 h to obtain the water-reducing aid shown in Formula 1. In the structural formula, m takes the value of 2 and n takes the value of 61. GPC is used to check the molecular weight distribution, and it shows that its molecular weight is about 6200 g / mol. Iodine value titration shows that the double bond retention rate is 99.6%, and the PEG content detection is 0.3%. Characterization: NMR (Varian INOVA 400 MHz) is used to characterize the chemical structure of the prepared product. 1313C NMR (400 MHz, DMSO-d6): δ = 17.1 ppm (s, 4C, CH3), 63.7 ppm (s, 2C, CH2), 73.1 ppm (s, 2C, CH2), 71.2 ppm (s, 120C, CH2), 68.4 ppm (s, 120C, CH2), 75.1 ppm (s, 4C, CH2), 72.6 ppm (s, 4C, CH2), 85 ppm (s, 2C, CH), 197.6 ppm (s, 2C, C), 125.2 ppm (s, 2C, CH), 38.6 ppm (s, 2C, CH2), 27.1 ppm (s, 2C, C), 25.1 ppm (s, 8C, CH3), 160.2 ppm (s, 2C, C), 129.9 ppm (s, 10C, CH), 139.3 ppm (s, 4C, C), 17.3 ppm (s, 4C, C), 122.5 ppm (s, 4C, C).

[0100] Then, at 80 °C, a mixed antioxidant with a concentration of 60 ppm (a 1:1 mass ratio mixture of BHT and 618) was added to the above reaction solution. After stirring for 30 min, a water-reducing aid composition was obtained. The results of the application performance test are shown in Table 1.

[0101] Comparative Example 1

[0102] A water-reducing aid was prepared by referring to the method of Example 4, with the only difference being that the alkaline earth metal catalyst D was replaced with an equal mass of KOH, and other operations remained unchanged.

[0103] When the reaction time reached 30 h, GPC was used to check the molecular weight distribution, showing that the molecular weight was about 4000 g / mol. Iodine value titration showed that the double bond retention rate was 80%, and the PEG content was detected to be 5%. This indicates that using KOH as a catalyst would cause a large amount of molecular weight loss. At the same time, due to the moisture in the KOH catalyst itself and the moisture generated during catalysis, a large amount of PEG by-products would be produced. The low double bond retention rate indicates that due to its low catalytic efficiency and long reaction time, a large number of double bonds are lost.

[0104] Its various performance indicators were tested, and the results are shown in Table 1.

[0105] Comparative Example 2

[0106] First, a catalyst was prepared by referring to the method of Example 4, with the only difference being that the raw material calcium hydroxide was replaced with sodium hydroxide, and other operations remained unchanged, to obtain an alkali metal catalyst;

[0107] Then, a water-reducing aid was prepared by referring to the method of Example 4, with the alkaline earth metal catalyst D replaced with the alkali metal catalyst prepared in this comparative example, and other operations remained unchanged, to obtain a water-reducing aid.

[0108] Test its various performance indicators, and the results are shown in Table 1.

[0109] Comparative Example 3

[0110] Prepare a water-reducing aid by referring to the method of Example 4, with the only difference being that: the PO reaction stage is omitted, and only the EO-stage feeding is retained for reaction. As a result, the product solidifies the kettle after 2 hours, and it is impossible to continue stirring and reacting.

[0111] Comparative Example 4

[0112] Prepare a water-reducing aid by referring to the method of Example 4, with the only difference being that: all the feeds in the EO reaction stage are replaced with PO, and other operations remain unchanged, to obtain a water-reducing aid.

[0113] Test its various performance indicators, and the results are shown in Table 1.

[0114] Test the water-reducing aids prepared in the examples and comparative examples of the present invention:

[0115] Prepare a water-reducing agent mother liquor and a water-reducing agent working solution according to the following formula, and then stir the water-reducing agent working solution, deionized water, and cement to check the water-reducing and slump-keeping properties of the water-reducing agent. The results are shown in Table 1. At the same time, measure the foam properties and slump-keeping properties of the water-reducing agent mother liquor, and the results are shown in Table 1:

[0116] Prepare a water-reducing agent mother liquor, and the raw material formula is as follows:

[0117]

[0118] At the given mother liquor synthesis temperature, add the water-reducing aid, the commercially available water-reducing agent Ouke 608 (methyl allyl alcohol polyoxyethylene ether), and deionized water into a 1000 ml four-necked flask, dissolve the solid substances by mechanical stirring, add hydrogen peroxide to obtain reaction bottom liquid I. Dissolve sodium L-ascorbate in deionized water, then add acrylic acid and mercaptoacetic acid in sequence, and stir the mixture evenly to prepare reaction dropping liquid II. 10 minutes after adding hydrogen peroxide to solution I, start to uniformly drop solution II, and control the dropping time to be 2 h ± 10 min. After the dropping is completed, keep stirring and aging the reaction for 0.5 h, then add the pre-prepared neutralizing solution III into the reaction solution, and stir evenly to obtain a water-reducing agent mother liquor, which is a colorless transparent viscous liquid.

[0119] Slump-keeping property test: Dilute the water-reducing agent mother liquor with deionized water by 4 times as the working solution, then mix 6.3 g of the working solution, 170 g of water, and 450 g of cement and stir for 2 minutes, observe the diameter of the natural spread of the cement cake, and record its diameter every half hour thereafter until 3 h.

[0120] Defoaming performance test: Dilute the superplasticizer mother liquor by 2 times, take 1 L as the circulating foam impact liquid, keep it at a constant temperature of 25 °C for 2 h, and measure the maximum foam height and defoaming time of the circulating impact foam by impacting for 2 min at a flow rate of 10 L / h.

[0121] Comparative Example 5

[0122] Without adding superplasticizer additives, synthesize the mother liquor with the commercially available Oak methallyl alcohol polyoxyethylene ether product at 40 °C, and measure its performance as shown in Table 1.

[0123] Comparative Example 6

[0124] Without adding superplasticizer additives, directly synthesize the mother liquor with the commercially available Oak methallyl alcohol polyoxyethylene ether product at 0 °C, and measure its performance as shown in Table 1.

[0125] Table 1 Data of slump retention and defoaming of the working fluid used in concrete

[0126]

[0127]

[0128] It can be seen from the data in Table 1 above that the water-reducing additives within the scope of the present invention can significantly improve the slump retention of commercially available superplasticizers when added in small amounts to ordinary superplasticizers, and greatly increase the temperature adaptation range during the synthesis process of the mother liquor. The slump retention performance of the superplasticizer mother liquor and the working fluid synthesized from the macromonomer is significantly improved compared with commercially available products.

[0129] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. Any equivalent changes or modifications made under the technical spirit disclosed by the present invention shall fall within the scope of the patent covered by the present invention.

Claims

1. A water-reducing aid having a structure as shown in Formula 1: In the formula, m independently takes values of 1 - 5; n independently takes values of 40 - 140; The preparation method of the water-reducing aid is that in a nitrogen environment, using astaxanthin as the initiator, adding an alkaline earth metal catalyst, first reacting with propylene oxide, and then reacting with ethylene oxide to obtain the water-reducing aid shown in Formula 1; The structure of the alkaline earth metal catalyst is as follows: wherein R represents an alkyl group having 6 to 16 carbon atoms, M represents an alkaline earth metal element; and p ranges from 1 to 30.

2. The water-reducing aid according to claim 1, wherein In Formula 1, m independently takes values of 1 - 3; n independently takes values of 50 - 80.

3. A preparation method of the water-reducing aid according to claim 1 or 2, characterized in that, The method is that in a nitrogen environment, using astaxanthin as the initiator, adding an alkaline earth metal catalyst, first reacting with propylene oxide, and then reacting with ethylene oxide to obtain the water-reducing aid shown in Formula 1; The structure of the alkaline earth metal catalyst is as follows: wherein R represents an alkyl group having 6 to 16 carbon atoms, M represents an alkaline earth metal element; p ranges from 1 to 30.

4. The preparation method according to claim 3, characterized in that, The dosage of the alkaline earth metal catalyst is 0.35 - 11.3% of the mass of astaxanthin.

5. The preparation method according to claim 3, characterized in that, In the structure of the alkaline earth metal catalyst, R represents one or more of n-hexyl, isooctyl, isodecyl, isoundecyl, isotridecyl, hexadecyl.

6. The preparation method according to claim 3, characterized in that, In the structure of the alkaline earth metal catalyst, M represents one or more of calcium, magnesium, barium.

7. The preparation method according to claim 3, wherein In the structure of the alkaline earth metal catalyst, p takes values of 2 - 10.

8. The preparation method according to claim 3, characterized in that, The dosage of the alkaline earth metal catalyst is 0.5 - 10% of the mass of astaxanthin.

9. The preparation method according to claim 3, wherein The preparation method of the alkaline earth metal catalyst is: in a nitrogen environment, under the condition of an alkaline catalyst, an alcohol with C6 - C16 reacts with propylene oxide, and then chloroacetic acid is added for reaction to obtain the alkaline earth metal catalyst.

10. The preparation method according to claim 9, characterized in that, The alkaline catalyst is selected from one or more of calcium hydroxide, barium hydroxide, and magnesium hydroxide; The alcohol with C6 - C16 is n-hexanol, isooctanol, isodecanol, isoundecanol, isotridecanol, hexadecanol; The mass ratio of the alcohol with C6 - C16 to the alkaline catalyst is 1:0.24 - 1.99; The mass ratio of the alcohol with C6 - C16 to propylene oxide is 1:0.2 - 17.1; The mass ratio of the alcohol with C6 - C16 to chloroacetic acid is 1:0.7 - 1.85; The reaction temperature of the alcohol with C6 - C16 and propylene oxide is 80 - 130 °C, the pressure is 0.1 - 0.6 MPaG, and the time is 0.5 - 2 h.

11. According to the preparation method described in claim 9, wherein The mass ratio of the alcohol with C6 - C16 to the alkaline catalyst is 1:0.29 - 1.

56.

12. The preparation method according to claim 9, wherein The mass ratio of the alcohol with C6 - C16 to propylene oxide is 1:1.2 - 10.

13. The preparation method according to claim 9, characterized in that, The mass ratio of the alcohol with C6 - C16 to chloroacetic acid is 1:0.8 - 1.

5.

14. The preparation method according to claim 9, characterized in that, The reaction temperature of the alcohol with C6 - C16 and propylene oxide is 100 - 130 °C, the pressure is 0.1 - 0.3 MpaG, and the time is 1 - 2 h.

15. The preparation method according to claim 9, wherein The propylene oxide is fed continuously, the pressure during the feeding process is controlled at 0.1 - 0.6 MPaG, the feeding time is 0.5 - 5 h, and the feeding time is not included in the above reaction time; Then the temperature for continuing the reaction with chloroacetic acid is 50 - 100 °C, the pressure is 0 - 0.1 MPaG, and the time is 1 - 3 h.

16. The preparation method according to claim 15, wherein The pressure during the feeding process is controlled at 0.1 - 0.3 MpaG, and the feeding time is 0.5 - 3 h.

17. The preparation method according to claim 15, characterized in that, The reaction temperature with chloroacetic acid is 60 - 80 °C, the pressure is 0 - 0.05 MpaG, and the time is 1 - 2 h.

18. The preparation method according to claim 3, characterized in that, For the astaxanthin described above, its water content should be lower than 200 ppm; The mass ratio of the astaxanthin to propylene oxide is 1:0.19 - 0.98; The mass ratio of the astaxanthin to ethylene oxide is 1:5.8 - 20.

7.

19. The preparation method according to claim 18, characterized in that, For the astaxanthin described above, its water content should be lower than 100 ppm.

20. The preparation method according to claim 18, characterized in that, The mass ratio of the astaxanthin to propylene oxide is 1:0.19 - 0.

59.

21. The preparation method according to claim 18, characterized in that, The mass ratio of the astaxanthin to ethylene oxide is 1:7.3 - 11.

8.

22. The preparation method according to claim 3, characterized in that, For the reaction with propylene oxide, the temperature is 120 - 180 °C and the time is 1 - 3 h; For the reaction with ethylene oxide, the temperature is 80 - 180 °C and the time is 0.5 - 3 h.

23. The preparation method according to claim 22, wherein, For the reaction with propylene oxide, the temperature is 130 - 160 °C and the time is 1 - 2 h.

24. The preparation method according to claim 22, characterized in that, For the reaction with ethylene oxide, the temperature is 100 - 120 °C and the time is 1 - 2 h.

25. The preparation method according to claim 3, characterized in that, The reaction process uses a batch reactor.

26. The preparation method according to claim 3, wherein, The feeding time of the propylene oxide is controlled to be 0.5 - 1.5 h, the pressure in the reaction kettle is controlled ≤ 0.6 MPaG, and the stirring is not started during the feeding of propylene oxide. After the feeding is completed, the stirring is started to initiate the reaction.

27. The preparation method according to claim 3, wherein The ethylene oxide is fed continuously. The pressure during the feeding process is controlled to be 0.1 - 0.6 MPaG, and the feeding time is 4 - 18 h.

28. The preparation method according to claim 27, characterized in that, The ethylene oxide is fed continuously. The pressure during the feeding process is controlled to be 0.1 - 0.3 MpaG, and the feeding time is 6 - 10 h.

29. The preparation method according to claim 3, characterized in that, The water-reducing aid further includes formulating an antioxidant into a water-reducing aid composition; Specifically, in the preparation method of the water-reducing aid, after the reaction is completed, an antioxidant is added to the reaction solution to obtain the water-reducing aid composition.

30. The preparation method according to claim 29, characterized in that, The antioxidant is a mixture of BHT and 618, and the mass ratio of the two is 1:0.9 - 1.

1.

31. The preparation method according to claim 30, wherein The antioxidant is a mixture of BHT and 618, and the mass ratio of the two is 1:

1.

32. The preparation method according to claim 29, wherein, The addition amount of the antioxidant in the reaction solution is 10 - 200 ppm.

33. The preparation method according to claim 32, characterized in that, The addition amount of the antioxidant in the reaction solution is 10 - 100 ppm.

34. The application of the water-reducing aid according to claim 1 or 2 or the water-reducing aid prepared by the method according to any one of claims 3 - 31 in the fields of construction and concrete.

35. The application according to claim 34, characterized in that, The water-reducing aid is used in combination with a water reducer, and its dosage is 0.01 - 0.5 wt% of the mass of the water reducer; The water-reducing aid is the water-reducing aid shown in Formula 1, or the water-reducing aid composition after adding an antioxidant; The types of water reducers are selected from methyl allyl alcohol polyoxyethylene ether, isopentenol polyoxyethylene ether, and vinyl polyoxyethylene ether.

36. The application according to claim 35, wherein The water-reducing aid is used in combination with a water reducer, and its dosage is 0.02 - 0.2 wt% of the mass of the water reducer.

37. The application according to claim 35, characterized in that, The types of water reducers are selected from Oak 608 / 702 and Oak 501 / 703.

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