A viscosity-reducing polycarboxylic acid collapse-preventing agent and its preparation method

Abstract

The present invention relates to a viscosity-reducing polycarboxylic acid slump-retaining agent and a preparation method thereof. Calculated by weight, the raw materials for the preparation of the viscosity-reducing polycarboxylic acid slump-retaining agent include 5 to 15 parts of phenyl phosphate; 75 to 15 parts of unsaturated polyether; 5 to 15 parts of unsaturated hydroxy ester; 0.5 to 2 parts of unsaturated acid A; 2 to 10 parts of a cross-linking monomer; 1 to 3 parts of an oxidizing agent; 1 to 3 parts of a reducing agent; 1 to 5 parts of a chain transfer agent; and water. The present invention introduces phenyl phosphate into the side chain of the viscosity-reducing polycarboxylic acid slump-retaining agent. Since the phenyl phosphate on the side chain has a cyclic structure, the steric hindrance effect of the viscosity-reducing polycarboxylic acid slump-retaining agent is increased, thereby reducing the viscosity of the concrete. In addition, since the phosphate group generated after the hydrolysis of phenyl phosphate has a retarding effect, the setting time of the concrete can be extended and cracks in the concrete can be reduced. The carboxyl-containing molecular chains released by the hydrolysis of phenyl phosphate are secondary adsorbed into the concrete, thereby achieving a slump-retaining effect.

Description

Technical Field

[0001] The invention relates to the technical field of concrete admixtures, in particular to a viscosity-reducing polycarboxylic acid slump-preventing agent and a preparation method thereof. Background Art

[0002] With the rapid development of the domestic construction industry, the strength grade of concrete is also constantly improving. High-strength and ultra-high-strength concrete has gradually been used in construction projects. However, due to the characteristics of high adhesive and low water-binder ratio of this type of concrete, its viscosity is high and pumping is difficult. It is difficult to apply it on a large scale in construction objects such as high-rise buildings and large-volume structures. Therefore, the market demand for high-strength concrete viscosity reducers continues to rise. Summary of the Invention

[0003] Based on this, it is necessary to provide a viscosity-reducing polycarboxylic acid slump retaining agent and a preparation method thereof, aiming to solve the technical problem of high viscosity of existing concrete.

[0004] To achieve the above object, the present invention provides a technical solution:

[0005] A viscosity-reducing polycarboxylic acid slump-retaining agent, wherein the raw materials for preparing the viscosity-reducing polycarboxylic acid slump-retaining agent include, in parts by weight:

[0006]

[0007] Preferably, the structural formula of the phenyl phosphate is as follows:

[0008]

[0009] Wherein, R includes an organic group with a double bond.

[0010] Preferably, the unsaturated polyether includes at least one of allyl polyoxyethylene polyoxypropylene ether, methallyl polyoxyethylene polyoxypropylene ether and isopentenyl polyoxyethylene polyoxypropylene ether.

[0011] Preferably, the unsaturated hydroxy ester includes at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate.

[0012] Preferably, the cross-linking monomer includes at least one of polyethylene glycol maleate and polyethylene glycol acrylate.

[0013] Preferably, the chain transfer agent includes at least one of mercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, 2-mercaptosuccinic acid, sodium methyl propene sulfonate and 2-acrylamide-2-methylpropane sulfonic acid.

[0014] The present invention also provides a method for preparing any of the above-described viscosity-reducing polycarboxylic acid collapse-preventing agents, comprising the following steps:

[0015] Mixing the unsaturated polyether, an oxidant and water to obtain liquid A;

[0016] Mixing the reducing agent and the chain initiator to obtain liquid B;

[0017] Mixing the phenyl phosphate, the unsaturated hydroxy ester, the crosslinking monomer, and the unsaturated acid A to obtain liquid C;

[0018] The solution B and the solution C are added dropwise to the solution A. After the addition is completed, the reaction is continued by keeping warm. After the insulation is completed, liquid alkali is added dropwise to adjust the pH of the solution to 6-7, thereby obtaining the viscosity-reducing polycarboxylic acid collapse-preventing agent.

[0019] Preferably, the preparation steps of the phenyl phosphate are as follows:

[0020] Unsaturated acid B and phenyl dichlorophosphate are mixed, and an acid binding agent is added, and the mixture is reacted at 20-40° C. for 2-3 hours to obtain the phenyl phosphate.

[0021] Preferably, the molar ratio of the unsaturated acid B to the phenyl dichlorophosphate is 1:1.

[0022] Preferably, the acid binding agent comprises at least one of pyridine, ethylenediamine and triethylamine.

[0023] Beneficial effects of the present invention:

[0024] The present invention introduces phenyl phosphate into the side chain of the viscosity-reducing polycarboxylic acid slump retaining agent. Since the phenyl phosphate on the side chain has a cyclic structure, the steric hindrance effect of the viscosity-reducing polycarboxylic acid slump retaining agent is increased, thereby reducing the viscosity of the concrete.

[0025] In addition, since the phosphate groups produced after the hydrolysis of phenyl phosphate have a retarding effect, they can prolong the setting time of concrete and reduce concrete cracks. The carboxyl-containing molecular chains released by the hydrolysis of phenyl phosphate are secondary adsorbed into the concrete, playing a role in preventing collapse. DETAILED DESCRIPTION

[0026] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below with reference to specific embodiments.

[0027] In the examples, the test methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0028] A viscosity-reducing polycarboxylic acid slump-retaining agent, wherein the raw materials for preparing the viscosity-reducing polycarboxylic acid slump-retaining agent include, by weight:

[0029]

[0030] More specifically, the raw materials for preparing the viscosity-reducing polycarboxylic acid collapse retaining agent further include 1 to 5 parts of ferrous sulfate in parts by weight, wherein the mass concentration of ferrous sulfate is 1% to 5%.

[0031] Specifically, the structural formula of phenyl phosphate is as follows:

[0032]

[0033] Wherein, R includes an organic group with a double bond, and more specifically, R includes any one of an acrylic group and a methacrylic group.

[0034] Specifically, the cross-linking monomer includes at least one of polyethylene glycol maleate and polyethylene glycol acrylate, wherein the polyethylene glycol is one of PEG-200, PEG-400 and PEG-600.

[0035] The present invention also provides a method for preparing any of the above viscosity-reducing polycarboxylic acid collapse-preventing agents, comprising the following steps:

[0036] S100. Mix unsaturated polyether, oxidant and water to obtain liquid A.

[0037] Specifically, the unsaturated polyether includes at least one of allyl polyoxyethylene polyoxypropylene ether, methallyl polyoxyethylene polyoxypropylene ether, and isopentenyl polyoxyethylene polyoxypropylene ether, and the molecular weight of the unsaturated polyether is 800 to 2400.

[0038] The oxidizing agent includes at least one of hydrogen peroxide and persulfate.

[0039] S200. Mix the reducing agent and the chain initiator to obtain liquid B.

[0040] Specifically, the reducing agent includes at least one of bleaching powder, L-ascorbic acid and hypophosphite.

[0041] The chain transfer agent includes at least one of mercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, 2-mercaptosuccinic acid, sodium methyl propene sulfonate, and 2-acrylamide-2-methylpropane sulfonic acid.

[0042] S300. Phenyl phosphate, unsaturated hydroxy ester, crosslinking monomer and unsaturated acid A are mixed to obtain liquid C.

[0043] Specifically, the unsaturated hydroxy ester includes at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

[0044] The unsaturated acid A includes at least one of acrylic acid, cinnamic acid, methacrylic acid, itaconic acid, and maleic acid.

[0045] S400. Add solution B and solution C dropwise to solution A. Continue to keep the temperature for 20 to 30 minutes after the addition is completed. After the temperature is maintained, add liquid alkali dropwise to adjust the pH of the solution to 6 to 7 to obtain a viscosity-reducing polycarboxylic acid collapse-preventing agent.

[0046] More specifically, the mass concentration of the liquid caustic soda is 32%, and the liquid caustic soda includes sodium hydroxide with a mass concentration of 32%.

[0047] The viscosity-reducing polycarboxylic acid slump-preventing agent for high-strength concrete synthesized in the present invention can reduce the viscosity of high-grade concrete, prolong the initial setting time of concrete, thereby improving the pumping efficiency of concrete, and prevent cracks and cracks caused by hydration heat in concrete, thereby facilitating the construction and later maintenance of high-grade concrete.

[0048] The present invention introduces phenyl phosphate into the side chain of the viscosity-reducing polycarboxylic acid slump retaining agent. Since the phenyl phosphate on the side chain has a cyclic structure, the steric hindrance effect of the viscosity-reducing polycarboxylic acid slump retaining agent is increased, thereby reducing the viscosity of the concrete.

[0049] In addition, since the phosphate groups produced after the hydrolysis of phenyl phosphate have a retarding effect, they can prolong the setting time of concrete and reduce concrete cracks. The carboxyl-containing molecular chains released by the hydrolysis of phenyl phosphate are secondary adsorbed into the concrete, playing a role in preventing collapse.

[0050] The preparation steps of phenyl phosphate are as follows:

[0051] Unsaturated acid B and phenyl dichlorophosphate are mixed, and an acid binding agent is added, and the mixture is reacted at 20-40° C. for 2-3 hours to obtain phenyl phosphate.

[0052] The acid-binding agent comprises at least one of pyridine, ethylenediamine and triethylamine, and the amount of the acid-binding agent used is 0.5% to 5% of the total mass of the reactants for preparing phenyl phosphate. The acid-binding agent serves as a catalyst to accelerate the reaction rate.

[0053] The unsaturated acid B includes at least one of acrylic acid, cinnamic acid, methacrylic acid, itaconic acid and maleic acid.

[0054] More specifically, the molar ratio of unsaturated acid B to phenyl dichlorophosphate is 1:1.

[0055] Example 1

[0056] Preparation of phenyl phosphate

[0057] Acrylic acid and phenyl dichlorophosphate were mixed in a molar ratio of 1:1, pyridine was added, and the mixture was reacted at 20°C for 3 hours to prepare phenyl phosphate. The pyridine content in the reaction mixture for preparing phenyl phosphate was 2% of the total mass of the reactants.

[0058] Preparation of viscosity-reducing polycarboxylic acid collapse-preventing agent

[0059] S100. 100 parts by mass of isopentenyl polyoxyethylene polyoxypropylene ether (molecular weight 1200) and 120 parts by mass of water were added to the reactor. After stirring and dispersing evenly, 3 parts by mass of hydrogen peroxide and 1 part by mass of ferrous sulfate with a mass concentration of 1% were added at one time. After stirring for 10 minutes, liquid A was obtained.

[0060] S200. Mix 1 part by mass of bleaching agent and 2 parts by mass of 2-mercaptopropionic acid to obtain liquid B.

[0061] S300. 7 parts by mass of the above-prepared phenyl phosphate, 8 parts by mass of hydroxypropyl acrylate, 8 parts of polyethylene glycol monomaleate and 1 part of acrylic acid are mixed to obtain liquid C.

[0062] S400. Add solution B and solution C dropwise to solution A. After the addition is completed, continue to insulate and react for 30 minutes. After the insulation is completed, add a 32% sodium hydroxide solution dropwise to adjust the pH of the solution to 7 to obtain a viscosity-reducing polycarboxylic acid collapse-preventing agent.

[0063] Example 2

[0064] The other steps are the same as those in Example 1, except that:

[0065] Cinnamic acid and phenyl dichlorophosphate were mixed at a molar ratio of 1:1, pyridine was added, and the mixture was reacted at 20°C for 3 hours to prepare phenyl phosphate. The pyridine content was 2% of the total mass of the reactants for preparing phenyl phosphate.

[0066] Example 3

[0067] The other steps are the same as those in Example 1, except for the following differences in preparing the viscosity-reducing polycarboxylic acid collapse-preventing agent:

[0068]

[0069] Comparative Example 1

[0070] The other steps are the same as those in Example 1, except that:

[0071] When preparing the viscosity-reducing polycarboxylic acid collapse retaining agent, no phenyl phosphate is added.

[0072] Comparative Example 2

[0073] The other steps are the same as those in Example 1, except that:

[0074] When preparing the viscosity-reducing polycarboxylic acid collapse-preventing agent, phenyl phosphate is replaced with benzene phosphate.

[0075] Comparative Example 3

[0076] The other steps are the same as those in Example 1, except that:

[0077] When preparing the viscosity-reducing polycarboxylic acid collapse retaining agent, no cross-linking monomer is added.

[0078] The polycarboxylic acid slump retaining agents prepared in Examples 1 to 3 and the polycarboxylic acid slump retaining agents prepared in Comparative Examples 1 to 3 were mixed into concrete, and the slump retention ability, inverted slump cone emptying time, and setting time of the concrete were tested to compare the effects of different slump retaining agents on the performance of concrete.

[0079] The concrete tests used river sand with an Mx of 2.4, crushed basalt stone with a continuous grade of 5 to 31.5 mm, Jingyang Jidong 42.5 ordinary Portland cement, and Datang Shenglong Grade II fly ash. Concrete performance testing was conducted in accordance with GB / T 50080-2016, "Standard for Test Methods for Properties of Ordinary Concrete Mixtures."

[0080] The concrete mix ratio is shown in Table 1.

[0081] The comparative results of concrete tests are shown in Table 2 Concrete test results.

[0082] Table 1 Concrete mix ratio Unit: kg / m 3

[0083]

[0084] Table 2 Concrete test results

[0085]

[0086] According to the performance test data of concrete mixed with different slump retaining agents in Table 2 above, in the 1h and 2h slump, setting time, and inverted slump cone emptying time tests of the concrete mixed with the samples of Examples 1, 2, and 3 of the present invention, in which phenyl phosphate was added during polymerization, after Example 2 replaced acrylic acid with cinnamic acid, the slump retention ability of the concrete decreased slightly, but the inverted cone time was reduced. It can be seen that replacing acrylic acid with cinnamic acid has a certain effect on reducing the viscosity of concrete;

[0087] In Example 3, the acid-ether ratio is increased compared to Example 1, so the slump retention ability of the sample mixed concrete is improved compared with Example 1, and the other properties are equivalent; the 1h and 2h slump, setting time, and inverted slump cone emptying time of the concrete mixed by the samples of Examples 1, 2, and 3 in which phenyl phosphate is added during polymerization in the present invention are significantly better than those of the concrete mixed by the samples of Comparative Examples 1 to 3, indicating that after phenyl phosphate is added to the polymerization in the present invention, the concrete slump retaining agent obtained has the functions of reducing viscosity and retarding setting, and the slump retaining performance is significantly better than that of the conventional slump retaining agent.

[0088] In Comparative Example 3, since no cross-linking monomer was added, the performance of the concrete mixed by the sample was lower than that of the concrete in Examples 1, 2, and 3 after 2 hours of maintenance. However, its concrete setting time and inverted slump cone emptying time were comparable to those in Examples 1, 2, and 3. Therefore, it can be seen that the addition of the cross-linking monomer improved the slump retention ability of the concrete after 2 hours, but had little effect on the setting time and viscosity of the concrete.

[0089] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention specification under the inventive concept of the present invention, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A viscosity-reducing polycarboxylic acid slump retaining agent, characterized in that: The raw materials for preparing the viscosity-reducing polycarboxylic acid slump retaining agent include, by weight: 5-15 parts of phenyl phosphate; 75-150 parts of unsaturated polyether; 5-15 parts of unsaturated hydroxy ester; Unsaturated acid A 0.5-2 parts; 2-10 parts of cross-linking monomer; 1~3 parts of oxidant; 1~3 parts of reducing agent; 1 to 5 parts of a chain transfer agent; and water; The structural formula of the phenyl phosphate is as follows: ； Wherein, R includes an organic group with a double bond; The preparation steps of the phenyl phosphate are as follows: Mix unsaturated acid B and phenyl dichlorophosphate, add an acid binding agent, and react at 20-40°C for 2-3 hours to obtain phenyl phosphate; The acid-binding agent comprises at least one of pyridine, ethylenediamine and triethylamine, and the amount of the acid-binding agent is 0.5% to 5% of the total mass of the reactants for preparing phenyl phosphate; The unsaturated acid A comprises at least one of acrylic acid, cinnamic acid, methacrylic acid, itaconic acid and maleic acid; The cross-linking monomer includes at least one of polyethylene glycol maleic acid monoester and polyethylene glycol acrylic acid monoester.

2. The viscosity-reducing polycarboxylic acid slump retaining agent according to claim 1, wherein The unsaturated polyether includes at least one of allyl polyoxyethylene polyoxypropylene ether, methallyl polyoxyethylene polyoxypropylene ether and isopentenyl polyoxyethylene polyoxypropylene ether.

3. The viscosity-reducing polycarboxylic acid slump retaining agent according to claim 1, wherein The unsaturated hydroxy ester includes at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate.

4. The viscosity-reducing polycarboxylic acid slump retaining agent according to claim 1, characterized in that: The chain transfer agent includes at least one of mercaptoacetic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, 2-mercaptosuccinic acid, sodium methyl propene sulfonate and 2-acrylamide-2-methylpropane sulfonic acid.

5. A method for preparing the viscosity-reducing polycarboxylic acid collapse retaining agent according to any one of claims 1 to 4, characterized in that: The steps include: Mixing the unsaturated polyether, an oxidant and water to obtain liquid A; Mixing the reducing agent and the chain transfer agent to obtain liquid B; Mixing the phenyl phosphate, the unsaturated hydroxy ester, the crosslinking monomer, and the unsaturated acid A to obtain liquid C; The solution B and the solution C are added dropwise to the solution A. After the addition is completed, the reaction is continued by keeping warm. After the insulation is completed, liquid alkali is added dropwise to adjust the pH of the solution to 6-7, thereby obtaining the viscosity-reducing polycarboxylic acid collapse-preventing agent.

6. The method for preparing the viscosity-reducing polycarboxylic acid collapse retaining agent according to claim 5, wherein: The molar ratio of the unsaturated acid B to the phenyl dichlorophosphate is 1:1.

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