Preparation method of cellulose ether grafted concrete slurry purifying agent

Abstract

The invention discloses a preparation method of a cellulose ether grafted concrete slurry purifying agent. The preparation method is characterized by comprising the following steps: (1) mixing and stirring urea, deionized water and hydroxypropyl methyl cellulose ether into transparent mucus; (2) adding a silane coupling agent, N, N-methylene bisacrylamide and a polyether monomer, and continuously stirring uniformly; (3) preparing three dropwise adding solutions and a polymerization inhibitor solution; (4) simultaneously dropwise adding the three dropwise adding liquids into the material obtained in the step (2) at a constant speed; and (5) keeping the temperature after dropwise adding, adding the polymerization inhibitor solution obtained in the step (3), and supplementing a proper amount of water to obtain the cellulose ether grafted concrete slurry purifying agent. The urea solution is used for preventing the agglomeration phenomenon of the cellulose ether in the synthesis process, and meanwhile, the coupling agent is used for connecting cellulose ether molecules to molecular side chains; the macromolecules connected with the cellulose ether structure can provide steric hindrance, so that the fullness degree of cement paste is improved, and the paste extraction effect is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of building admixtures, and particularly relates to a method for preparing a cellulose ether grafted concrete slurry agent. Background Art

[0002] With the continuous acceleration of urbanization, people's requirements for commercial concrete are increasing. However, the deterioration of raw materials has led to an increase in uncontrollable factors in the concrete production process. It has become normal to add water to concrete after it is transported over a long distance to the construction site. If you are not careful, it is very easy to cause accidents such as concrete segregation and pump blockage. On the other hand, in order to meet the performance requirements of concrete, polycarboxylic acid high-performance water reducers came into being and have been widely used and developed. However, during use, due to over-mixing and over-mixing, concrete stratification and segregation often occur. The cohesion between the components of the mixture is not enough to resist the sinking of coarse aggregate, resulting in the separation of the components of the concrete mixture, resulting in uneven internal composition and structure. The separation of coarse aggregate and mortar, or the separation of coarse aggregate from the mixture as a whole, seriously affects the workability of concrete, causing pipe blockage, pump blockage, stratification, water seepage, etc. These problems not only affect the mechanical properties, microscopic properties, structural properties, durability and long-term properties of concrete, but also affect physical and chemical reactions, thereby affecting the later strength growth and service life of concrete.

[0003] For concrete with segregation, there is a lack of effective solutions on site, and usually the only solution is to return it to the company for distribution and cement treatment, or to scrap it because of the long round trip time. This practice not only causes certain economic losses, but also pollutes the environment and wastes resources. Therefore, improving the production and transportation process of concrete, as well as developing more efficient concrete additives, is of great significance to improving concrete quality, reducing losses and protecting the environment. Summary of the invention

[0004] The present invention aims to overcome the defects of the prior art and provide a method for preparing a cellulose ether grafted concrete slurry agent.

[0005] The technical solution of the present invention is as follows:

[0006] A method for preparing a cellulose ether grafted concrete slurry agent comprises the following steps:

[0007] (1) Mix urea, deionized water and hydroxypropyl methylcellulose ether and stir until a transparent viscous liquid is obtained;

[0008] (2) adding a silane coupling agent, N,N-methylenebisacrylamide and a polyether monomer with a molecular weight of 2400-3000 to the material obtained in step (1), and continuing to stir evenly;

[0009] (3) preparing drop solution A: oxidant + deionized water, preparing drop solution B: unsaturated ester monomer + unsaturated carboxylic acid + deionized water, preparing drop solution C: reducing agent + deionized water, preparing inhibitor solution: deionized water + inhibitor;

[0010] (4) Within 50-70 minutes, dropwise addition liquid A, dropwise addition liquid B and dropwise addition liquid C are simultaneously added dropwise to the material obtained in step (2) at a uniform speed;

[0011] (5) After the addition is completed, the mixture is kept warm for 0.8-1.2 hours. After the heat preservation is completed, the inhibitor solution obtained in step (3) is added, and water is added in an appropriate amount to obtain a cellulose ether grafted concrete slurry agent.

[0012] In a preferred embodiment of the present invention, the molecular weight of the hydroxypropyl methylcellulose ether is 50,000 to 100,000.

[0013] In a preferred embodiment of the present invention, the polyether monomer is methyl allyl polyoxyethylene ether or isoprene alcohol polyoxyethylene ether.

[0014] In a preferred embodiment of the present invention, the silane coupling agent is KH560 or KH570.

[0015] In a preferred embodiment of the present invention, the oxidizing agent is ammonium persulfate or potassium persulfate.

[0016] In a preferred embodiment of the present invention, the reducing agent is vitamin C or sodium formaldehyde sulfoxylate.

[0017] In a preferred embodiment of the present invention, the unsaturated ester monomer is hydroxyethyl acrylate or hydroxypropyl acrylate.

[0018] In a preferred embodiment of the present invention, the unsaturated carboxylic acid is acrylic acid or methacrylic acid.

[0019] In a preferred embodiment of the present invention, the polymerization inhibitor is p-hydroxyanisole or hydroquinone.

[0020] In a preferred embodiment of the present invention, the mass ratio of urea, hydroxypropyl methylcellulose ether, silane coupling agent, N,N-methylenebisacrylamide, polyether monomer, oxidant, reducing agent, unsaturated ester monomer, unsaturated carboxylic acid and inhibitor is 7-9:5-7:0.4-0.6:0.1-0.3:12-17:0.7-0.9:0.3-0.5:8-10:6-9:0.04-0.06.

[0021] The beneficial effects of the present invention are:

[0022] 1. The present invention prevents the agglomeration of cellulose ether during the synthesis process by using urea solution, and at the same time uses a coupling agent to connect the cellulose ether molecules to the molecular side chains; the macromolecule connected with the cellulose ether structure can provide steric hindrance, thereby improving the fullness of the cement paste and achieving a slurry lifting effect.

[0023] 2. The present invention introduces a polyether macromonomer into the molecular structure, and its long side chain can play a good dispersing role in concrete. At the same time, during the storage process of the cellulose ether grafted concrete slurry agent, this structure also helps to reduce the agglomeration of cellulose ether and improve the stability of the product.

[0024] 3. The present invention adds a micro-crosslinking agent N,N-methylenebisacrylamide to the system, so that a micro-crosslinked network structure is formed between polymer molecules, which can further enhance the water retention effect of the concrete slurry agent and improve the workability of the concrete.

[0025] 4. Unsaturated carboxylic acid monomers are introduced into the molecular structure of the present invention to provide carboxylic acid groups, which can be adsorbed on the surface of cement particles in the concrete slurry raising agent, so as to better play the role of each molecular structure of the slurry raising agent in the cement paste, thereby achieving a better water retention and slurry raising effect.

[0026] 5. The process of preparing the cellulose ether grafted concrete slurry agent of the present invention is carried out at normal temperature and pressure, which reduces energy consumption, and the production process is simple and the production cost is low. This method not only improves the performance of the slurry agent, but also reduces the environmental impact and cost of the production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Shows the results of the storage stability test of the samples. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further illustrated and described below through specific implementation modes in combination with the accompanying drawings.

[0029] Embodiment 1:

[0030] (1) Weigh 8 parts of urea and 200 parts of deionized water in a flask, stir to dissolve, then add 5 parts of hydroxypropyl methylcellulose ether with a molecular weight of 50,000, and continue stirring for 6 hours until the solution becomes a transparent viscous liquid;

[0031] (2) Add 0.4 parts of silane coupling agent KH570, 0.15 parts of micro-crosslinking agent N,N-methylenebisacrylamide + 15 parts of 3000 molecular weight isoprene alcohol polyoxyethylene ether to the material obtained in step (1) by weight, and continue to stir evenly; (3) Prepare A drop solution: 0.8 parts of ammonium persulfate + 15 parts of deionized water, prepare B drop solution: 8 parts of hydroxyethyl acrylate + 6 parts of methacrylic acid + 15 parts of deionized water, prepare C drop solution: 0.35 parts of vitamin C + 15 parts of deionized water, and prepare inhibitor solution: 15 parts of deionized water + 0.05 parts of p-hydroxyanisole;

[0032] (4) Within 60±10 min, dropwise addition liquid A, dropwise addition liquid B and dropwise addition liquid C are simultaneously added dropwise to the material obtained in step (2) at a uniform speed;

[0033] (5) After the addition is completed, the mixture is kept warm for 1 hour. After the heat preservation is completed, the inhibitor solution obtained in step (3) is added, and 35 parts of deionized water are added by weight to obtain a cellulose ether grafted concrete slurry agent PCA-1.

[0034] Embodiment 2:

[0035] (1) Weigh 8 parts of urea and 200 parts of deionized water in a flask, stir to dissolve, then add 5.8 parts of hydroxypropyl methylcellulose ether with a molecular weight of 100,000, and continue stirring for 6 hours until the solution becomes a transparent viscous liquid;

[0036] (2) Add 0.55 parts of silane coupling agent KH560, 0.25 parts of micro-crosslinking agent N,N-methylenebisacrylamide + 15 parts of methyl allyl polyoxyethylene ether with a molecular weight of 2400 to the material obtained in step (1) by weight, and continue to stir evenly;

[0037] (3) Prepare drop solution A by weight: 0.7 parts of ammonium persulfate + 15 parts of deionized water; prepare drop solution B: 9 parts of hydroxypropyl acrylate + 7 parts of acrylic acid + 15 parts of deionized water; prepare drop solution C: 0.35 parts of sodium formaldehyde sulfoxylate + 15 parts of deionized water; prepare inhibitor solution: 15 parts of deionized water + 0.05 parts of hydroquinone;

[0038] (4) Within 60±10 min, dropwise addition liquid A, dropwise addition liquid B and dropwise addition liquid C are simultaneously added dropwise to the material obtained in step (2) at a uniform speed;

[0039] (5) After the addition is completed, the mixture is kept warm for 1 hour. After the heat preservation is completed, the inhibitor solution obtained in step (3) is added, and 40 parts by weight of deionized water are added to obtain a cellulose ether grafted concrete slurry agent PCA-2.

[0040] Embodiment 3:

[0041] (1) 8 parts of urea and 200 parts of deionized water were weighed in a flask, and after stirring to dissolve, 6.5 parts of hydroxypropyl methylcellulose ether with a molecular weight of 100,000 were added, and stirring was continued for 6 hours until the solution became transparent and viscous;

[0042] (2) Add 0.6 parts of silane coupling agent KH570, 0.3 parts of micro-crosslinking agent N,N-methylenebisacrylamide + 15 parts of 3000 molecular weight isoprene alcohol polyoxyethylene ether by weight to the material obtained in step (1), and continue to stir evenly; (3) Prepare A drop solution by weight: 0.85 parts of potassium persulfate + 15 parts of deionized water; prepare B drop solution: 9.5 parts of hydroxyethyl acrylate + 9 parts of methacrylic acid + 15 parts of deionized water; prepare C drop solution: 0.45 parts of vitamin C + 15 parts of deionized water; prepare inhibitor solution: 15 parts of deionized water + 0.05 parts of p-hydroxyanisole;

[0043] (4) Within 60±10 min, dropwise addition liquid A, dropwise addition liquid B and dropwise addition liquid C are simultaneously added dropwise to the material obtained in step (2) at a uniform speed;

[0044] (5) After the addition is completed, the mixture is kept warm for 1 hour. After the heat preservation is completed, the inhibitor solution obtained in step (3) is added, and 40 parts by weight of deionized water are added to obtain a cellulose ether grafted concrete slurry agent PCA-3.

[0045] Comparison of implementation effects:

[0046] The cellulose ether grafted concrete slurry agents PCA-1 to PCA-3 prepared according to Examples 1 to 3 of the present invention were subjected to a sample storage stability test, and the concrete workability, concrete slump loss, and compressive strength tests were compared between the concrete without the concrete slurry agent and the concrete with the commercial concrete water-retaining slurry agent. The concrete slump test method was carried out in accordance with the relevant provisions of GB8076-2008 "Concrete Admixtures"; the concrete compressive strength was carried out in accordance with the relevant provisions of GB / T50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete". The mix proportions and test results of Test 2 are shown in Tables 1 and 2, and the mix proportions and test results of Test 3 are shown in Tables 3 and 4.

[0047] Test 1: The results of the sample storage stability test are as follows Figure 1 As shown, the synthesized product remains clear and transparent after long-term storage without precipitation or turbidity.

[0048] Test 2: The concrete grouting agent is compounded at a dosage of 1.5% of the water reducing agent. The specific formula is shown in Table 1 below:

[0049] Table 1

[0050]

[0051] The test results are shown in Table 2 below:

[0052] Table 2

[0053]

[0054] Test 3: The concrete grouting agent was compounded at 1.5% of the water reducing agent. The specific formula is shown in Table 3 below:

[0055] Table 3

[0056]

[0057] The test results are shown in Table 4 below:

[0058] Table 4

[0059]

[0060] By comparing the blank sample and the commercially available concrete slurry agent in the concrete test, it can be seen that the concrete mixture of the cellulose ether grafted concrete slurry agent prepared by Examples 1 to 3 of the present invention has rich slurry, good workability, small slump loss, and no effect on the concrete strength.

[0061] The above description is only a preferred embodiment of the present invention, and therefore cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A method for preparing a cellulose ether grafted concrete slurry agent, characterized in that: The steps include: (1) Mix urea, deionized water and hydroxypropyl methylcellulose ether and stir until a transparent viscous liquid is obtained; (2) adding a silane coupling agent, N,N-methylenebisacrylamide and a polyether monomer with a molecular weight of 2400-3000 to the material obtained in step (1), and continuing to stir evenly; (3) preparing drop solution A: oxidant + deionized water, preparing drop solution B: unsaturated ester monomer + unsaturated carboxylic acid + deionized water, preparing drop solution C: reducing agent + deionized water, preparing inhibitor solution: deionized water + inhibitor; (4) Within 50-70 minutes, dropwise addition liquid A, dropwise addition liquid B and dropwise addition liquid C are simultaneously added dropwise to the material obtained in step (2) at a uniform speed; (5) After the addition is completed, the mixture is kept warm for 0.8-1.2 hours. After the heat preservation is completed, the inhibitor solution obtained in step (3) is added, and water is added in an appropriate amount to obtain a cellulose ether grafted concrete slurry agent.

2. The preparation method according to claim 1, characterized in that: The molecular weight of the hydroxypropyl methylcellulose ether is 50,000 to 100,000.

3. The preparation method according to claim 1, characterized in that: The polyether monomer is methyl allyl polyoxyethylene ether or isoprene alcohol polyoxyethylene ether.

4. The preparation method according to claim 1, characterized in that: The silane coupling agent is KH560 or KH570.

5. The preparation method according to claim 1, characterized in that: The oxidant is ammonium persulfate or potassium persulfate.

6. The preparation method according to claim 1, characterized in that: The reducing agent is vitamin C or sodium formaldehyde sulfoxylate.

7. The preparation method according to claim 1, characterized in that: The unsaturated ester monomer is hydroxyethyl acrylate or hydroxypropyl acrylate.

8. The preparation method according to claim 1, characterized in that: The unsaturated carboxylic acid is acrylic acid or methacrylic acid.

9. The preparation method according to claim 1, characterized in that: The polymerization inhibitor is p-hydroxyanisole or hydroquinone.

10. The preparation method according to any one of claims 1 to 9, characterized in that: The mass ratio of the urea, hydroxypropyl methylcellulose ether, silane coupling agent, N,N-methylenebisacrylamide, polyether monomer, oxidant, reducing agent, unsaturated ester monomer, unsaturated carboxylic acid and inhibitor is 7-9:5-7:0.4-0.6:0.1-0.3:12-17:0.7-0.9:0.3-0.5:8-10:6-9:0.04-0.06.

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