Special retarding foam stabilizer for wet-mixed mortar as well as preparation method and application of special retarding foam stabilizer

Abstract

The invention provides a special delayed coagulation type foam stabilizer for wet-mixed mortar and a preparation method and application thereof, and the foam stabilizer is prepared by taking a monomer A as a raw material, sequentially performing hydrophobic modification and hydrophilic modification on the monomer A and then performing phosphorylation reaction, the monomer A is an alkyl chain structure compound with amino groups at two ends; the hydrophobic modification operation is that epoxypropane is adopted to carry out epoxidation reaction; the hydrophilic modification operation is to carry out epoxidation reaction by adopting ethylene oxide; the molar ratio of the monomer A to the epoxypropane to the ethylene oxide is 1: (40-72): (4-56); the molar ratio of the epoxypropane to the ethylene oxide is (1-3): 1. The novel wet-mixed mortar admixture disclosed by the invention has relatively strong foam stabilizing performance and also has relatively strong retarding performance, so that the plasticity of mortar can be kept for a long time, the construction time of the mortar can be greatly prolonged, and the construction efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, and in particular to a slow-setting foam stabilizer specially used for wet-mix mortar, and a preparation method and application thereof. Background Art

[0002] With the rapid development of China's economy and the intensification of urbanization, the construction area of ​​houses in the construction industry has continued to grow. Therefore, the demand for building mortar has also continued to increase, with an annual consumption of hundreds of millions of tons. In addition, with the change of policies, the mandatory promotion of environmental protection and energy conservation, green development and transformation and upgrading of the construction industry, ready-mixed mortar is difficult to adapt to the new development of the construction industry due to on-site dust and noise pollution, which has brought new opportunities for the development of premixed mortar. As a kind of premixed mortar, wet-mixed mortar is more cost-effective in construction efficiency and economy. Therefore, its development speed has been rapid in the past two years. As the most important admixture of wet-mixed mortar, wet-mixed mortar admixture cannot be ignored. It is an additive added to cement and sand to improve the performance of cement mortar. In cement wet-mixed mortar without mortar admixture, poor mortar plasticity, insufficient plastic preservation time, and fast loss of mortar consistency on site often occur.

[0003] After searching, Chinese patent CN117682793A discloses a wet-mix mortar admixture, which mainly includes water-retaining thickener, attapulgite, defoamer, stabilizer, retarder, and anti-cracking agent. We know that in actual production, the bulk density of wet-mix mortar is generally around 1800kg / m3, so air-entraining components are usually added to the mortar admixture. However, this patent does not contain air-entraining components, but defoamers, and the effects of the two on performance are opposite.

[0004] Chinese patent CN117820538A discloses an anti-mud wet-mix mortar admixture, which is obtained by copolymerizing cationic monomers with acrylamide and acrylic acid, and is adsorbed on the surface of clay particles through hydrogen bonds, electrostatic attraction, intermolecular forces, etc., thereby inhibiting the hydration expansion of clay particles and the adsorption of mortar admixtures, and solving the influence of clay and waste slurry water on the working performance of mortar. This is to reduce the influence of mud content in machine-made sand on mortar admixtures, thereby extending the working performance of mortar.

[0005] Chinese patent CN117209201A discloses a wet-mix mortar admixture to address the poor workability, difficult to control open time and rapid loss of working performance caused by replacing natural sand with recycled sand powder in concrete. The wet-mix mortar admixture is a combination of a self-synthesized thickener and a water-retaining agent with a polycarboxylic acid mother liquor, coconut oil fatty acid diethanolamide, a silicone resin polyether emulsion, sodium gluconate, white sugar, molasses, sodium α-olefin sulfonate and sodium dodecyl sulfate. The mortar system can be stabilized for a long time, plasticity can be maintained, mortar stratification can be avoided, and the development of the mortar mechanical properties can be improved.

[0006] Chinese patent CN116639905B discloses a mortar admixture, the main components of which are thermoplastic resin, protein solution, modified silica, sodium alginate solution, polycarboxylic acid water reducer, air entraining agent, water retaining agent, coating agent, graphene-based material, EVA, and compound solution. It can reduce the negative impact of powder on mortar performance, reduce the limitations of admixtures, and improve the stability of mortar. Summary of the invention

[0007] In view of the fact that wet-mixed mortar in the prior art often has a relatively long plastic preservation time due to different construction requirements, there is no problem when the mortar is just produced in the early stage, but the state of the mortar will deteriorate after being placed for a long time, and even harden and cannot be used, thus wasting a lot of materials, that is, the wet-mixed mortar is insufficient in maintaining the workability for a long time. The present application proposes a slow-setting foam stabilizer for wet-mixed mortar, a preparation method and application thereof.

[0008] A slow-setting foam stabilizer specially used for wet-mixed mortar, the foam stabilizer is obtained by using A monomer as a raw material, and sequentially performing hydrophobic modification and hydrophilic modification on A monomer and then performing a phosphorylation reaction;

[0009] The above-mentioned A monomer is an alkyl chain structure compound with amino groups at both ends; the above-mentioned hydrophobic modification operation is an epoxidation reaction using propylene oxide; the above-mentioned hydrophilic modification operation is an epoxidation reaction using ethylene oxide;

[0010] The molar ratio of the above-mentioned A monomer: propylene oxide: ethylene oxide is 1: (40-72): (4-56);

[0011] The molar ratio of propylene oxide to ethylene oxide is (1-3):1.

[0012] The above-mentioned A monomer structure is shown in the following formula (1):

[0013] Where n=2~8.

[0014] The structure of the foam stabilizer is shown in the following formula (2):

[0015]

[0016] Wherein n=2~8, m=10~18, q=1~14.

[0017] A preparation method of a slow-setting foam stabilizer for wet-mixed mortar comprises the following steps: (1) placing monomer A in a reaction kettle, adding an alkaline catalyst, slowly introducing propylene oxide into the reaction kettle under nitrogen protection, and after aging reaction, slowly introducing ethylene oxide to continue aging reaction, cooling and degassing after the reaction is completed to obtain an addition product; (2) placing the addition product in a toluene solvent, then adding phosphorus oxychloride, and then slowly adding pyridine dropwise, cooling and filtering after the reaction is completed, and dissolving the filter cake in water to obtain a slow-setting foam stabilizer.

[0018] In the above step (1), the reaction temperature is 120-160° C., the reaction pressure is less than 0.55 MPa; the aging reaction time of introducing propylene oxide is 2-4 hours; the aging reaction time of introducing ethylene oxide is 1-3 hours.

[0019] The alkaline catalyst in the above step (1) is any one of sodium hydride, sodium methoxide, potassium hydride and potassium methoxide; the molar ratio of the alkaline catalyst to the amount of monomer A is (0.01-0.1):1.

[0020] The specific operation of the nitrogen protection condition can be: sealing the reactor and introducing nitrogen twice to replace the air.

[0021] The reaction temperature of the above step (2) is 90-95° C. and the reaction time is 4-6 h.

[0022] The molar ratio of the addition product in step (2), phosphorus oxychloride and pyridine is 1:(1-1.1):(1-1.1).

[0023] The concentration of the foam stabilizer after being dissolved in water in the above step (2) is 40-60%.

[0024] The dosage of the foam stabilizer is 0.2 to 2‰ of the total cementitious material mass.

[0025] Compared with the prior art, this application has the following advantages:

[0026] (1) There are few mortar foam stabilizers on the market, and most of them are stabilized by adding thickeners, which has a poor foam stabilization effect. The slow-setting foam stabilizer for wet-mixed mortar of the present application is innovative in molecular structure. It is a surfactant with a hydrophilic and hydrophobic structure obtained by chemical synthesis. It has strong foam stabilization performance and can stabilize bubbles and maintain performance for a long time.

[0027] (2) The wet-mix mortar admixture of the present application introduces phosphate in its structure, which has a strong retarding effect. This structure has a very significant effect on extending the open time of the wet-mix mortar;

[0028] The present invention discloses a slow-setting foam stabilizer for wet-mixed mortar and its preparation method and application, wherein an alkyl chain with amino groups at both ends is first connected to a certain amount of propylene oxide for hydrophobic modification, then connected to a certain amount of ethylene oxide for hydrophilic modification, and finally the modified product is phosphorylated to obtain a slow-setting foam stabilizer for wet-mixed mortar. The novel wet-mixed mortar admixture of the present invention has strong foam stabilizing performance and also has strong slow-setting performance, which can not only keep the mortar plastic for a long time, but also greatly prolong the construction time of the mortar and improve the construction efficiency. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solution of the present invention. Obviously, the described embodiments are only 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.

[0030] The raw materials used in the following examples and comparative examples are all commercially available. The raw materials used in the examples are all commercially available products, among which the reagents (analytical grade) and organic solvents (chemically pure) are purchased from Sinopharm Chemical Reagent Co., Ltd., and sodium α-olefin sulfonate is from China Light Industry Co., Ltd.; in the application examples, the cement used is Conch Cement P.O42.5 cement. The sand is natural sand with a fineness modulus of Mx=2.6, and the fly ash is grade II. The consistency and bulk density of the mortar are measured and calculated according to the method described in JGJ / T 70-2009 "Standard for Test Methods for Basic Properties of Building Mortar". In each example and comparative example, the dosage of the admixture and the amount of water are adjusted to maintain the initial consistency of the mortar at 90±5mm and the initial bulk density of the mortar at 1800±50kg / m 3 .

[0031] Example 1

[0032] Place 1 mol of ethylenediamine chain in a reactor, add 0.01 mol of NaH, seal the reactor after a period of time, introduce nitrogen twice for air replacement, then heat to 120°C, the reaction pressure is less than 0.5Mpa, slowly introduce 40 mol of propylene oxide into the reactor, mature the reaction for 2 hours, then slowly introduce 16 mol of ethylene oxide, continue to mature the reaction for 1 hour, cool down and degas, and obtain the addition product.

[0033] Place 1 mol of the addition product obtained above in solvent toluene, then add 4.4 mol of phosphorus oxychloride, raise the temperature to 90°C, and then slowly drop pyridine. After the addition is completed, continue to keep warm for 4 hours. After cooling, filter and add water to dissolve into a liquid with a concentration of 50%, which is a slow-setting foam stabilizer.

[0034] Example 2

[0035] Place 1 mol of propylene diamine chain in a reactor, add 0.1 mol of KH, seal the reactor after a period of time, introduce nitrogen twice for air replacement, then heat to 160°C, the reaction pressure is less than 0.55Mpa, slowly introduce 72 mol of propylene oxide into the reactor, mature the reaction for 4 hours, then slowly introduce 56 mol of ethylene oxide, continue the mature reaction for 3 hours, cool down and degas, and obtain the addition product.

[0036] Place 1 mol of the addition product obtained above in solvent toluene, then add 4.4 mol of phosphorus oxychloride, raise the temperature to 92°C, and then slowly drop pyridine. After the addition is completed, continue to keep warm for 6 hours. After cooling, filter and add water to dissolve into a liquid with a concentration of 50%, which is a slow-setting foam stabilizer.

[0037] Example 3

[0038] Place 1 mol of diaminobutane chain in a reactor, add 0.05 mol of KH, seal the reactor after a period of time, introduce nitrogen twice for air replacement, then heat to 150°C, the reaction pressure is less than 0.55Mpa, slowly introduce 48 mol of propylene oxide into the reactor, mature for 3 hours, then slowly introduce 16 mol of ethylene oxide, continue to mature for 2 hours, cool down and degas, and obtain the addition product.

[0039] Place 1 mol of the addition product obtained above in solvent toluene, then add 4.4 mol of phosphorus oxychloride, raise the temperature to 92°C, and then slowly drop pyridine. After the addition is completed, continue to keep warm for 5 hours. After cooling, filter and add water to dissolve into a liquid with a concentration of 50%, which is a slow-setting foam stabilizer.

[0040] Example 4

[0041] Place 1 mol of pentamethylenediamine chain in a reactor, add 0.05 mol of NaH, seal the reactor after a period of time, introduce nitrogen twice for air replacement, then heat to 150°C, the reaction pressure is less than 0.55Mpa, slowly introduce 64 mol of propylene oxide into the reactor, mature the reaction for 3 hours, then slowly introduce 32 mol of ethylene oxide, continue to mature the reaction for 3 hours, cool down and degas, and obtain the addition product.

[0042] Place 1 mol of the addition product obtained above in solvent toluene, then add 4.4 mol of phosphorus oxychloride, raise the temperature to 92°C, and then slowly drop pyridine. After the addition is completed, continue to keep warm for 6 hours. After cooling, filter and add water to dissolve into a liquid with a concentration of 50%, which is a slow-setting foam stabilizer.

[0043] Example 5

[0044] Place 1 mol of octanediamine chain in a reactor, add 0.1 mol of CH3ONa, seal the reactor after a period of time, introduce nitrogen twice for air replacement, then raise the temperature to 140°C, the reaction pressure is less than 0.5Mpa, slowly introduce 56 mol of propylene oxide into the reactor, mature the reaction for 2 hours, then slowly introduce 44 mol of ethylene oxide, continue the mature reaction for 3 hours, cool down and degas, and obtain the addition product.

[0045] Place 1 mol of the addition product obtained above in solvent toluene, then add 4.4 mol of phosphorus oxychloride, raise the temperature to 92°C, and then slowly drop pyridine. After the addition is completed, continue to keep warm for 5 hours. After cooling, filter and add water to dissolve into a liquid with a concentration of 50%, which is a slow-setting foam stabilizer.

[0046] Comparative Example 1

[0047] The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, only an addition product is prepared, and the addition product is not phosphorylated. The other reaction conditions are the same as those in Example 1.

[0048] Comparative Example 2

[0049] The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, ethylenediamine is directly reacted with phosphorus oxychloride without first reacting with propylene oxide or ethylene oxide, and the other reaction conditions are the same as those in Example 1.

[0050] Comparative Example 3

[0051] The difference between Comparative Example 3 and Example 1 is that the amount of propylene oxide used in Comparative Example 3 is 8 mol, and the other reaction conditions are the same as those in Example 1.

[0052] Comparative Example 4

[0053] The difference between Comparative Example 4 and Example 1 is that the amount of propylene oxide used in Comparative Example 4 is 64 mol, and the other reaction conditions are the same as those in Example 1.

[0054] The wet mix mortar ratio is shown in Table 1 below:

[0055] Table 1

[0056] Conch Cement PO 42.5 / g Fly ash grade II / g Natural sand (Mx = 2.6) / g 250 30 1380

[0057] Test Example 1: Wet-mix mortar performance test

[0058] The performance test results of each embodiment and comparative example are shown in Table 2 below (In the embodiments and comparative examples, the dosage of plasticizer and open time regulator is the same, wherein the dosage of plasticizer is 3kg / m 3 , development time regulator is 6kg / m 3The plasticizer and development time regulator were purchased from Jiangsu Subote New Materials Co., Ltd. The dosage of the slow-setting foam stabilizer for wet-mixed mortar is the percentage of the cement dosage).

[0059] Table 2

[0060]

[0061]

[0062] It can be seen from the data in the above table that the blank sample without the addition of the foam stabilizer of the present application has a bulk density loss rate of about 3.4% in 24 hours and a bulk density loss rate of about 10% in 48 hours, while the wet-mixed mortars of Examples 1 to 5 to which the slow-setting foam stabilizer is added have a bulk density loss rate of less than 1.8% in 24 hours, a bulk density loss rate of less than 3.1% in 32 hours, and a bulk density loss rate of less than 5.6% in 48 hours, indicating that the wet-mixed mortar with the addition of the foam stabilizer of the present invention has significantly increased bubble stability, which has a good effect on maintaining the plasticity of the mortar for a long time, greatly improving construction efficiency, and reducing construction risks. For the blank sample without the addition of the foam stabilizer of the present application, the consistency loss rate in 24 hours is about 12%, and the consistency loss rate in 48 hours is about 60%. For the wet-mixed mortars of Examples 1 to 5 to which the retarding foam stabilizer is added, the consistency loss rate in 24 hours is less than 6%, the consistency loss rate in 32 hours is less than 16%, and the consistency loss rate in 48 hours is less than 42%, indicating that the wet-mixed mortar to which the foam stabilizer of the present invention is added has a good retarding effect and can prolong the open time of the wet-mixed mortar.

[0063] In Comparative Example 1, the addition product was not phosphorylated during the synthesis process, so the mortar bulk density loss rate was small, indicating that the foam stabilization effect was good, but the consistency loss rate was significantly higher, indicating that it was less effective in extending the open time of the wet-mixed mortar.

[0064] In Comparative Example 2, ethylenediamine is directly reacted with phosphorus oxychloride during the synthesis process without first reacting with propylene oxide and ethylene oxide. Therefore, the mortar consistency loss rate is small, indicating that the open time effect on the wet-mixed mortar is good, but the bulk density loss rate is large, indicating that the foam stabilizing effect is not good and the plastic retention effect is poor.

[0065] It can be seen from the data results of Comparative Examples 3 and 4 that when the molar ratio of propylene oxide to ethylene oxide is too large or too small, although the mortar consistency loss rate is small, the bulk density loss rate is large, that is, the foam stabilizing effect is not good.

[0066] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A slow-setting foam stabilizer for wet-mix mortar, characterized in that: The foam stabilizer uses A monomer as raw material. It is obtained by sequentially subjecting the A monomer to hydrophobic modification and hydrophilic modification and then to phosphorylation reaction; The A monomer is an alkyl chain structure compound with amino groups at both ends; The hydrophobic modification operation is to use propylene oxide to carry out epoxidation reaction; The hydrophilic modification operation is to use ethylene oxide to carry out epoxidation reaction; The molar ratio of the A monomer: propylene oxide: ethylene oxide is 1: (40-72): (4-56); The molar ratio of propylene oxide to ethylene oxide is (1-3):

1.

2. The slow-setting foam stabilizer for wet-mix mortar according to claim 1, characterized in that: The A monomer structure is shown in the following formula (1): Where n=2~8.

3. The slow-setting foam stabilizer for wet-mix mortar according to claim 1, characterized in that: The foam stabilizer structure is shown in the following formula (2): Wherein n=2~8, m=10~18, q=1~14.

4. The method for preparing a slow-setting foam stabilizer for wet-mix mortar according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) placing monomer A in a reaction kettle, adding an alkaline catalyst, and slowly introducing propylene oxide into the reaction kettle under nitrogen protection. After the aging reaction, slowly introducing ethylene oxide to continue the aging reaction. After the reaction is completed, cooling, degassing and discharging the material to obtain an addition product; (2) placing the addition product in a toluene solvent, then adding phosphorus oxychloride, and then slowly adding pyridine dropwise. After the reaction is completed, cooling and filtering are performed. After the filter cake is dissolved in water, a slow-setting foam stabilizer is obtained.

5. The preparation method according to claim 4, characterized in that: The reaction temperature in step (1) is 120-160° C., and the reaction pressure is less than 0.55 MPa; the aging reaction time of introducing propylene oxide is 2-4 hours; The aging reaction time of introducing ethylene oxide is 1 to 3 hours.

6. The preparation method according to claim 4, characterized in that: The alkaline catalyst in step (1) is any one of sodium hydride, sodium methoxide, potassium hydride and potassium methoxide; the molar ratio of the alkaline catalyst to the amount of monomer A is (0.01-0.1):

1.

7. The preparation method according to claim 4, characterized in that: The reaction temperature of step (2) is 90-95° C., and the reaction time is 4-6 hours.

8. The preparation method according to claim 4, characterized in that: The molar ratio of the addition product, phosphorus oxychloride and pyridine in step (2) is 1:(1-1.1):(1-1.1).

9. The preparation method according to claim 4, characterized in that: The concentration of the foam stabilizer after being dissolved in water in step (2) is 40-60%.

10. Application of a slow-setting foam stabilizer for wet-mix mortar, characterized in that: The dosage of the foam stabilizer is 0.2-2‰ of the total mass of the cementitious material; the foam stabilizer is the foam stabilizer described in any one of claims 1-3 or the foam stabilizer obtained by the preparation method described in any one of claims 4-9.

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