Solid molecular sieve plastic retaining agent as well as preparation method and application thereof

Abstract

The invention provides a solid molecular sieve plastic retaining agent as well as a preparation method and application thereof, and belongs to the technical field of concrete. The solid molecular sieve plastic retaining agent comprises 300-400 parts of a molecular sieve, 320-380 parts of a template agent, 22-40 parts of an unsaturated carboxylic acid monomer, 20-40 parts of an oxidizing agent, 4-12 parts of a reducing agent, 0.3-2 parts of a chain transfer agent and 2-10 parts of sodium hydroxide. The solid molecular sieve plastic retaining agent disclosed by the invention solves the problem that the slump of freshly mixed concrete is too fast in gradual loss, can effectively keep the long-time better flowing property of a concrete mixture, and brings convenience and possibility for on-site engineering construction and long-distance transportation of the concrete. Meanwhile, compared with liquid products in the market, the solid molecular sieve plastic retaining agent is non-toxic and harmless, and is more convenient to package, transport and store.

Description

Technical Field

[0001] The invention relates to the technical field of concrete, and in particular to a solid molecular sieve plasticizer and a preparation method and application thereof. Background Art

[0002] Concrete is one of the most important civil engineering materials in contemporary times. With the rapid development of the economy and the continuous improvement of construction level, people have higher and higher requirements for the quality of concrete. However, in engineering practice, especially in the construction process of concrete, the rapid loss of slump of fresh concrete has always been a problem that plagues normal construction and urgently needs to be solved. Especially during long-distance transportation, the rapid loss of slump of concrete not only affects the construction progress, but also greatly affects the performance and quality of concrete.

[0003] At present, plasticizers are a type of admixture that can reduce the slump loss of concrete within a period of time. The use of high-performance concrete admixtures can alleviate the slump loss of concrete mixtures to a certain extent, such as polycarboxylate water reducers, but they are still subject to certain restrictions in application, especially in summer when the temperature is high, there is still a problem of too fast slump loss. In addition, the plasticizer products on the market are all liquid, which also brings certain difficulties to the transportation and promotion of plasticizer products. Therefore, the development of an efficient solid plasticizer that can continuously release water reducers into the concrete system, maintain the initial slump level as much as possible, and ensure a low slump loss of concrete mixtures is an urgent problem to be solved in the field of concrete plasticizers. Summary of the invention

[0004] The purpose of the present invention is to provide a solid molecular sieve plasticizer and a preparation method and application thereof. The solid molecular sieve plasticizer can reduce the slump loss rate of concrete, maintain the fluidity of the concrete mixture, and solve the problem that the slump loss of the concrete mixture is too fast and cannot meet the long-distance transportation requirements.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a solid molecular sieve plasticizer, comprising the following raw materials in parts by weight:

[0007] 300-400 parts of molecular sieves; 320-380 parts of templates; 22-40 parts of unsaturated carboxylic acid monomers; 20-40 parts of oxidants; 4-12 parts of reducing agents; 0.3-2 parts of chain transfer agents; and 2-10 parts of alkali reagents.

[0008] Preferably, the molecular sieve includes one or more of clinoptilolite molecular sieve and mordenite molecular sieve.

[0009] Preferably, the template comprises one or more of vinyl polyoxyethylene ether, diethylene glycol monovinyl ether and diethylene glycol monoethyl ether.

[0010] Preferably, the unsaturated carboxylic acid monomer includes one or more of acrylic acid, acrylic ester, acryloyl chloride and itaconic acid.

[0011] Preferably, the oxidant includes one or more of sodium hypochlorite, hydrogen peroxide and sodium percarbonate.

[0012] Preferably, the reducing agent includes one or more of bleaching powder, ferrous sulfate and stannous sulfate.

[0013] Preferably, the chain transfer agent includes one or more of mercaptopropionic acid, mercaptoethanol and sodium hypophosphite; and the alkaline agent includes an aqueous sodium hydroxide solution.

[0014] Preferably, the polymerization reaction temperature is 15-25° C., and the time is 2.5-3.0 hours; the adsorption temperature is 15-25° C., and the time is 30-40 minutes.

[0015] The present invention provides a method for preparing the solid molecular sieve plasticizer described in the above technical solution, comprising the following steps:

[0016] Mixing a template, an oxidant and water to obtain a first mixed material;

[0017] Mixing a reducing agent, a chain transfer agent and water to obtain a second mixed material;

[0018] The first mixed material, the second mixed material and an aqueous solution of an unsaturated carboxylic acid monomer are mixed, an alkali reagent is added, the pH value is adjusted to 5 to 7, and a polymerization reaction is carried out to obtain a high molecular polymer;

[0019] The high molecular polymer is mixed with the molecular sieve for adsorption, and the obtained product is sequentially vacuum filtered and dried to obtain a solid molecular sieve plasticizer.

[0020] The present invention provides the use of the solid molecular sieve plasticizer described in the above technical solution or the solid molecular sieve plasticizer prepared by the preparation method described in the above technical solution in concrete.

[0021] The solid molecular sieve plasticizer provided by the present invention utilizes the adsorption-desorption principle of the porous structure of the molecular sieve to adsorb the high molecular polymer formed by all raw material reactions onto the surface of the molecular sieve and inside the pores for storage. The high molecular polymer contains -COO -The group can be adsorbed on the surface of cement particles to form an adsorption double layer, change the Zeta potential of the cement particle surface, keep the cement particles away, and thus improve the flowability of concrete. After being added to the concrete, the adsorbed polymer molecules are slowly and continuously released, thereby maintaining the adsorption of the polymer on the surface of cement particles in the concrete system for a long time, so that the cement particles are in a dispersed state, and the long-term fluidity effect of the concrete system is maintained, so as to achieve the purpose of reducing the excessive loss of concrete slump. At the same time, the reducing agent component in the plasticizer can promote the polymerization of unsaturated carboxylic acid monomers through redox reactions to ensure the generation of polymers with specific structures. The polycarboxylic acid polymer can improve the fluidity of concrete and reduce the viscosity of concrete by adsorbing on the surface of cement particles; the oxidant component in the plasticizer can improve the purity of the plasticizer product, reduce the concentration of impurities, improve the flow effect per unit volume of concrete, and reduce the slump loss by using its own oxidizing property in the reaction.

[0022] Compared with the prior art, the solid molecular sieve plasticizer of the present invention can significantly reduce the slump loss rate of concrete mixture, solve the problem of too fast slump loss of fresh concrete over time, effectively maintain the good flow performance of concrete mixture for a long time, and bring convenience and possibility for concrete engineering construction and long-distance transportation. At the same time, the molecular sieve plasticizer is a solid powder, non-toxic and harmless, and is more convenient for packaging, transportation and storage than liquid products on the market. The results of the embodiment show that the concrete to which the solid molecular sieve plasticizer is added has a concrete mixture slump of 1h basically unchanged, a slump loss of about 1% over time at 2h, and a slump loss of about 5% over time at 3h, which can still meet the pumping demand. At the same time, the strength of concrete at each age meets the relevant construction requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a physical picture of the molecular sieve plasticizer product prepared in Example 3. DETAILED DESCRIPTION

[0024] The present invention provides a solid molecular sieve plasticizer, comprising the following raw materials in parts by weight:

[0025] 300-400 parts of molecular sieves; 320-380 parts of templates; 22-40 parts of unsaturated carboxylic acid monomers; 20-40 parts of oxidants; 4-12 parts of reducing agents; 0.3-2 parts of chain transfer agents; and 2-10 parts of alkali reagents.

[0026] In the present invention, unless otherwise specified, the raw materials or reagents used are commercially available products well known in the art.

[0027] In terms of mass fractions, the raw materials for preparing the solid molecular sieve plasticizer provided by the present invention include 300 to 400 parts of molecular sieves, more preferably 325 to 370 parts, and further preferably 340 to 350 parts. In the present invention, the molecular sieve preferably includes one or more of clinoptilolite molecular sieve and mordenite molecular sieve, more preferably clinoptilolite molecular sieve and mordenite molecular sieve, and the mass ratio of the clinoptilolite molecular sieve and mordenite molecular sieve is preferably 3 to 8: 2 to 5, more preferably 5 to 7: 3 to 4, and further preferably 5 to 6: 3.3 to 3.5. The present invention has no special limitation on the source of the molecular sieve, and it can be obtained in a well-known manner; in an embodiment of the present invention, the clinoptilolite molecular sieve and mordenite molecular sieve are specifically natural zeolite molecular sieves produced in Weifang, Shandong, and the fineness is 800 mesh.

[0028] In the present invention, the molecular sieve has a three-dimensional network structure, and its large number of uniformly distributed pores and neatly arranged holes give it strong adsorption properties, and can adsorb the prepared high-molecular polymer on its surface or in its pores. When added to concrete, the high-molecular polymer is slowly released through the physical desorption effect of the molecular sieve itself, and the reaction continues, thereby achieving the purpose of reducing the time-dependent slump loss rate of concrete.

[0029] Based on the mass fraction of the molecular sieve, the raw material for preparing the solid molecular sieve plasticizer provided by the present invention includes 320 to 380 parts of template, more preferably 330 to 370 parts, and further preferably 350 to 360 parts; the template preferably includes one or more of vinyl polyoxyethylene ether, diethylene glycol monovinyl ether and diethylene glycol monoethyl ether, more preferably vinyl polyoxyethylene ether, diethylene glycol monovinyl ether and diethylene glycol monoethyl ether, and the mass ratio of the vinyl polyoxyethylene ether, diethylene glycol monovinyl ether and diethylene glycol monoethyl ether is preferably 1 to 3: 1.5 to 4: 2 to 5, more preferably 1.5 to 2: 2.7 to 3.5: 3 to 4, and further preferably 1.9 to 2.1: 2.5 to 3: 3 to 3.5. The present invention utilizes a template to improve the polymerization activity during the synthesis of the plasticizer product, and by adjusting the ratio of the template to the unsaturated carboxylic acid monomer, the dispersibility of the plasticizer product is improved, so that the product has stronger adaptability.

[0030] Based on the mass fraction of the molecular sieve, the raw materials for preparing the solid molecular sieve plasticizer provided by the present invention include 22 to 40 parts of unsaturated carboxylic acid monomers, more preferably 27 to 36 parts, and further preferably 30 to 32 parts; the unsaturated carboxylic acid monomers preferably include one or more of acrylic acid, acrylic ester, acryloyl chloride and itaconic acid, more preferably acrylic acid, acrylic ester, acryloyl chloride and itaconic acid.

[0031] In the present invention, the acrylate is preferably methacrylate or hydroxyethyl acrylate.

[0032] In the present invention, the mass ratio of acrylic acid, acrylic acid ester, acryloyl chloride and itaconic acid is preferably 1-3:1.5-3:1-2:0.5-2, more preferably 1.4-2.5:1.8-2.7:1.2-1.8:0.9-1.6, and further preferably 1.8-2.2:2.0-2.5:1.4-1.6:1.2-1.3. In the present invention, the unsaturated carboxylic acid monomer generates a structure with polyacrylic acid or polyacrylate as the main chain through polymerization reaction, which provides a main body for the subsequent grafting reaction. This molecular structure is adsorbed to the surface of cement particles in cement paste through electrostatic action, and electrostatic repulsion and steric hindrance are introduced between cement particles, thereby achieving good dispersion of cement particles and improving the fluidity and workability of concrete.

[0033] Based on the mass fraction of the molecular sieve, the raw materials for preparing the solid molecular sieve plasticizer provided by the present invention include 20 to 40 parts of oxidant, more preferably 25 to 35 parts, and further preferably 29 to 30 parts; the oxidant preferably includes one or more of sodium hypochlorite, hydrogen peroxide and sodium percarbonate, more preferably sodium hypochlorite, hydrogen peroxide and sodium percarbonate, and the mass ratio of sodium hypochlorite, hydrogen peroxide and sodium percarbonate is preferably 1 to 4:2 to 4:2 to 6, more preferably 2.5 to 2.8:2.9 to 3.5:4 to 5. The mass concentration of the hydrogen peroxide is preferably 30%. The present invention utilizes an oxidant to promote the polymerization reaction between unsaturated carboxylic acid monomers, so that the monomer molecules are connected together by chemical reaction to form a high molecular weight polymer chain, thereby improving the purity of the plasticizer product.

[0034] Based on the mass fraction of the molecular sieve, the raw materials for preparing the solid molecular sieve plasticizer provided by the present invention include 4 to 12 parts of a reducing agent, more preferably 5 to 10 parts, and further preferably 7 to 8 parts; the reducing agent preferably includes one or more of bleaching block, ferrous sulfate and stannous sulfate, more preferably bleaching block, ferrous sulfate and stannous sulfate, and the mass ratio of bleaching block, ferrous sulfate and stannous sulfate is preferably 0.5 to 1: 2 to 12: 4 to 20, more preferably 0.6 to 0.9: 4 to 10: 8 to 16, and further preferably 0.7 to 0.8: 6 to 8: 10 to 13. The present invention utilizes a reducing agent to carry out a reduction reaction, promotes the polymerization of unsaturated carboxylic acid monomers, and ensures the generation of a high molecular polymer with a specific structure. The polycarboxylic acid polymer can improve the fluidity of concrete and reduce the viscosity of concrete by adsorbing on the surface of cement particles.

[0035] Based on the mass fraction of the molecular sieve, the raw material for preparing the solid molecular sieve plasticizer provided by the present invention includes 0.3 to 2 parts of chain transfer agent, more preferably 0.8 to 1.6 parts, and further preferably 1.0 to 1.2 parts; the chain transfer agent preferably includes one or more of mercaptopropionic acid, mercaptoethanol and sodium hypophosphite, more preferably mercaptopropionic acid, mercaptoethanol and sodium hypophosphite, and the mass ratio of mercaptopropionic acid, mercaptoethanol and sodium hypophosphite is preferably 1 to 3: 2 to 3: 0.6 to 1.2, more preferably 1.5 to 2.5: 2.2 to 2.8: 0.7 to 1.1, and further preferably 1.8 to 2.1: 2.4 to 2.6: 0.9 to 1.0. The present invention utilizes the regulating effect of the chain transfer agent to transfer the active species on the growing polymer chain to the chain transfer agent during the polymerization process, thereby interrupting the polymerization reaction and forming a new active center, which helps to control the molecular weight and molecular weight distribution of the polymer and ensure the performance of the plasticizer.

[0036] Based on the mass fraction of the molecular sieve, the raw material for preparing the solid molecular sieve plasticizer provided by the present invention includes 2 to 10 parts of an alkali agent (calculated by mass fraction of liquid), more preferably 3 to 8 parts, and further preferably 4.2 to 6 parts. The alkali agent preferably includes an aqueous sodium hydroxide solution; the mass concentration of the aqueous sodium hydroxide solution is preferably 30%.

[0037] The present invention provides a method for preparing the solid molecular sieve plasticizer described in the above technical solution, comprising the following steps:

[0038] Mixing a template, an oxidant and water to obtain a first mixed material;

[0039] Mixing a reducing agent, a chain transfer agent and water to obtain a second mixed material;

[0040] The first mixed material, the second mixed material and an aqueous solution of an unsaturated carboxylic acid monomer are mixed, an alkali reagent is added, the pH value is adjusted to 5 to 7, and a polymerization reaction is carried out to obtain a high molecular polymer;

[0041] The high molecular polymer is mixed with the molecular sieve for adsorption, and the obtained product is sequentially vacuum filtered and dried to obtain a solid molecular sieve plasticizer.

[0042] The present invention preferably adds a template agent and an oxidant to water at room temperature, performs a first stirring, waits for them to be completely dissolved, obtains a first mixed material, mixes a reducing agent, a chain transfer agent and water, obtains a second mixed material; simultaneously drips an aqueous solution of an unsaturated carboxylic acid monomer (preferably 60% by mass concentration) (the dropping time is 50 minutes) and a second mixed material (the dropping time is 60 minutes) into the first mixed material, drips uniformly and stirs continuously during the entire dropping period, adds an alkali reagent after the dropping is completed, adjusts the pH value to 5-7, performs a polymerization reaction, mixes the obtained high molecular polymer with a molecular sieve, adsorbs under the second stirring condition, performs vacuum filtration, puts the filtered slurry into an oven for drying, collects the dried powder and grinds it to obtain a solid molecular sieve plasticizer.

[0043] In the present invention, the first stirring time is preferably 15 to 30 min, more preferably 20 min, and the stirring rate is preferably 30 to 60 r / min, more preferably 45 r / min; during the dropwise addition, the stirring speed is 60 to 90 r / min, more preferably 70 to 80 r / min.

[0044] In the present invention, the polymerization reaction temperature is preferably 15 to 25° C., more preferably 20° C., and the polymerization reaction time is preferably 2.5 to 3.0 h, more preferably 3.0 h.

[0045] In the present invention, the stirring rate of the second stirring is preferably 30-60r / min, more preferably 45r / min; the adsorption temperature is preferably 15-25°C, more preferably 20°C; the time is preferably 30-40min, more preferably 35min; the vacuum degree of the vacuum filtration is preferably -0.04-0.02MPa, more preferably -0.03MPa; the drying temperature is preferably 40-50°C, more preferably 45°C, and the time is preferably 1-3h, more preferably 2.5h; the grinding fineness is preferably through a 45μm sieve, and the sieve residue is 5-10%, more preferably 7%.

[0046] The solid molecular sieve plasticizer provided by the present invention utilizes the adsorption-desorption principle of the porous structure of the molecular sieve to adsorb the high molecular polymer onto the surface of the molecular sieve and inside the pores for storage, and then slowly and continuously releases the adsorbed high molecular polymer molecules after being added to the concrete, thereby maintaining the adsorption amount of the water reducer on the surface of the cement particles in the concrete system for a long time, making the cement particles in a dispersed state, maintaining the fluidity effect of the concrete system for a long time, and achieving the purpose of reducing the excessive loss of concrete slump. At the same time, the reducing agent component in the plasticizer can promote the polymerization of unsaturated carboxylic acid monomers through redox reactions, ensuring the generation of high molecular polymers with specific structures; the oxidizing agent component in the plasticizer can improve the purity of the plasticizer product and reduce the impurity concentration by utilizing its own oxidizing property in the reaction.

[0047] The present invention provides the application of the solid molecular sieve plasticizer described in the above technical solution or the solid molecular sieve plasticizer prepared by the preparation method described in the above technical solution in concrete. The present invention has no special limitation on the application method, and the application can be carried out according to methods well known in the art.

[0048] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0049] In the following examples, the parts represent parts by mass, and there is no limitation on the magnitude thereof, and the parts may represent g or kg;

[0050] In the following examples, the clinoptilolite molecular sieve and the mordenite molecular sieve are specifically natural zeolite molecular sieves produced in Weifang, Shandong, and the fineness of both is 800 mesh.

[0051] Example 1

[0052] The raw materials for preparing the molecular sieve plasticizer provided in this embodiment are:

[0053] 350 parts of molecular sieve, 360 parts of template, 30 parts of unsaturated carboxylic acid monomer, 29 parts of oxidant, 8 parts of reducing agent, 0.9 parts of chain transfer agent, 4 parts of sodium hydroxide aqueous solution (mass concentration is 30%, calculated by mass of solution);

[0054] The molecular sieves are clinoptilolite molecular sieve and mordenite molecular sieve, and the mass ratio of each component is clinoptilolite molecular sieve:mordenite molecular sieve=5:3.5.

[0055] The template agent is vinyl polyoxyethylene ether and diethylene glycol monovinyl ether, and the mass ratio of each component is vinyl polyoxyethylene ether: diethylene glycol monovinyl ether=2:2.5.

[0056] The unsaturated carboxylic acid monomers are acrylic acid, hydroxyethyl acrylate, acryloyl chloride and itaconic acid, and the mass ratio of each component is acrylic acid: acrylate: acryloyl chloride: itaconic acid = 2:2.5:1.5:1.

[0057] The oxidant is sodium hypochlorite, hydrogen peroxide (mass concentration 30%) and sodium percarbonate, and the mass ratio of each component is sodium hypochlorite: hydrogen peroxide: sodium percarbonate = 2:3:4.

[0058] The reducing agent is bleaching agent, ferrous sulfate and stannous sulfate, and the mass ratio of the components is bleaching agent: ferrous sulfate: stannous sulfate = 0.8:7:12.

[0059] The chain transfer agent is mercaptopropionic acid, mercaptoethanol and sodium hypophosphite, and the mass ratio of the components is mercaptopropionic acid: mercaptoethanol: sodium hypophosphite = 2:2.3:0.9.

[0060] Preparation method:

[0061] Under normal temperature conditions, a template, an oxidant and water are added into a three-necked flask, the mass ratio of the template, the oxidant and the water being 360:29:280, and stirred for 20 minutes at a stirring rate of 45 r / min until they are completely dissolved, to obtain a first mixed material;

[0062] Mixing a reducing agent, a chain transfer agent and water to obtain a second mixed material;

[0063] Simultaneously adding an unsaturated carboxylic acid aqueous solution (mass concentration 60%) and a second mixed material to the first mixed material, the unsaturated carboxylic acid aqueous solution adding time is 50 min, the second mixed material adding time is 60 min, the addition is continued under stirring, the stirring rate is 80 r / min, then adding a NaOH aqueous solution to the three-necked flask, adjusting the system pH to 7, and performing a polymerization reaction at 20° C. for 3.0 h to obtain a high molecular polymer;

[0064] The above-mentioned high molecular polymer is mixed with the molecular sieve, and the mixture is stirred and adsorbed at 20°C for 35 minutes at a stirring rate of 45 r / min. The obtained mixture is vacuum filtered with a vacuum degree of -0.03 MPa. The filtered slurry is dried in an oven at a drying temperature of 45°C and a drying time of 2.5 hours. The dried powder is collected and ground to obtain a solid molecular sieve plasticizer. The product fineness is 45 μm sieve and the sieve residue is 7%.

[0065] Example 2

[0066] The raw materials for preparing the solid molecular sieve plasticizer provided in this embodiment are:

[0067] 335 parts of molecular sieves, 350 parts of templates, 30 parts of unsaturated carboxylic acid monomers, 29 parts of oxidants, 7 parts of reducing agents, 1 part of chain transfer agents, and 3.8 parts of sodium hydroxide aqueous solution (mass concentration is 30%, based on the mass of the solution).

[0068] The molecular sieves are clinoptilolite molecular sieve and mordenite molecular sieve, and the mass ratio of each component is clinoptilolite molecular sieve:mordenite molecular sieve=5:4.

[0069] The template agent is vinyl polyoxyethylene ether, diethylene glycol monovinyl ether and diethylene glycol monoethyl ether, and the mass ratio of each component is vinyl polyoxyethylene ether: diethylene glycol monovinyl ether: diethylene glycol monoethyl ether=1.9:2.0:3.5.

[0070] The unsaturated carboxylic acid monomers are acrylic acid and methacrylic acid ester, and the mass ratio of each component is acrylic acid: acrylic acid ester=2.5:2.

[0071] The oxidant is sodium hypochlorite, hydrogen peroxide (mass concentration 30%) and sodium percarbonate, and the mass ratio of each component is sodium hypochlorite: hydrogen peroxide: sodium percarbonate = 2.5:3:3.5.

[0072] The reducing agents are bleaching agent and ferrous sulfate, and the mass ratio of the components is bleaching agent: ferrous sulfate = 0.7:8.

[0073] The chain transfer agent is mercaptopropionic acid, mercaptoethanol and sodium hypophosphite, and the mass ratio of the components is mercaptopropionic acid: mercaptoethanol: sodium hypophosphite = 2:2.4:0.9.

[0074] The preparation method of the solid molecular sieve plasticizer is the same as that in Example 1.

[0075] Example 3

[0076] The raw materials for preparing the solid molecular sieve plasticizer provided in this embodiment are:

[0077] 340 parts of molecular sieve, 360 parts of template, 35 parts of unsaturated carboxylic acid monomer, 35 parts of oxidant, 9 parts of reducing agent, 1.3 parts of chain transfer agent, 4 parts of sodium hydroxide aqueous solution (mass concentration is 30%, calculated by mass of solution).

[0078] Wherein, the molecular sieve is clinoptilolite molecular sieve.

[0079] The template agent is vinyl polyoxyethylene ether and diethylene glycol monovinyl ether, and the mass ratio of each component is vinyl polyoxyethylene ether: diethylene glycol monovinyl ether=2:3.

[0080] The unsaturated carboxylic acid monomers are acrylic acid and acryloyl chloride, and the mass ratio of the components is acrylic acid: acrylate = 2.0:1.5.

[0081] The oxidant is sodium hypochlorite and hydrogen peroxide (mass concentration 30%), and the mass ratio of each component is sodium hypochlorite: hydrogen peroxide = 2.5:3.

[0082] The reducing agents are bleaching agent and ferrous sulfate, and the mass ratio of the components is bleaching agent: ferrous sulfate = 0.8:8.

[0083] The chain transfer agent is mercaptopropionic acid and sodium hypophosphite, and the mass ratio of each component is mercaptopropionic acid: sodium hypophosphite = 2:1.

[0084] The preparation method of the solid molecular sieve plasticizer is the same as that in Example 1.

[0085] Example 4

[0086] The raw materials for preparing the solid molecular sieve plasticizer provided in this embodiment are:

[0087] 340 parts of molecular sieve, 360 parts of template, 32 parts of unsaturated carboxylic acid monomer, 30 parts of oxidant, 8 parts of reducing agent, 1.2 parts of chain transfer agent, 3.8 parts of sodium hydroxide aqueous solution (mass concentration is 30%, calculated by mass of solution).

[0088] Wherein, the molecular sieve is mordenite molecular sieve.

[0089] The template agent is vinyl polyoxyethylene ether and diethylene glycol monovinyl ether, and the mass ratio of each component is vinyl polyoxyethylene ether: diethylene glycol monovinyl ether=2:2.8.

[0090] The unsaturated carboxylic acid monomers are acrylic acid, methacrylate and acryloyl chloride, and the mass ratio of each component is acrylic acid: methacrylate = 1.8:2.2:1.6.

[0091] The oxidants are sodium hypochlorite and hydrogen peroxide (mass concentration 30%), and the mass ratio of each component is sodium hypochlorite: hydrogen peroxide=2.3:2.9.

[0092] The reducing agents are bleaching agent and ferrous sulfate, and the mass ratio of the components is bleaching agent: ferrous sulfate = 0.7:8.

[0093] The chain transfer agent is mercaptopropionic acid, mercaptoethanol and sodium hypophosphite, and the mass ratio of the components is mercaptopropionic acid: mercaptoethanol: sodium hypophosphite = 2:2.5:1.

[0094] The preparation method of the solid molecular sieve plasticizer is the same as that in Example 1.

[0095] Example 5

[0096] The raw materials for preparing the solid molecular sieve plasticizer provided in this embodiment are:

[0097] 370 parts of molecular sieve, 370 parts of template agent, 36 parts of unsaturated carboxylic acid monomer, 35 parts of oxidant, 10 parts of reducing agent, 1.6 parts of chain transfer agent, 4.2 parts of sodium hydroxide aqueous solution (mass concentration is 30%, calculated by mass of solution).

[0098] The molecular sieve includes clinoptilolite molecular sieve and mordenite molecular sieve, and the mass ratio of each component is clinoptilolite molecular sieve:mordenite molecular sieve=7:4.

[0099] Wherein, the template agent is diethylene glycol monovinyl ether.

[0100] The unsaturated carboxylic acid monomers are acrylic acid, acryloyl chloride and itaconic acid, and the mass ratio of the components is acrylic acid: acryloyl chloride: itaconic acid = 2.0:1.6:1.3.

[0101] The oxidant is hydrogen peroxide (mass concentration 30%) and sodium percarbonate, and the mass ratio of each component is hydrogen peroxide:sodium percarbonate=3:4.

[0102] The reducing agent is bleaching powder and stannous sulfate, and the mass ratio of the components is bleaching powder: stannous sulfate = 1:16.

[0103] Wherein, the chain transfer agent is mercaptopropionic acid.

[0104] The preparation method of the solid molecular sieve plasticizer is the same as that in Example 1.

[0105] Example 6

[0106] The raw materials for preparing the solid molecular sieve plasticizer provided in this embodiment are:

[0107] 350 parts of molecular sieve, 370 parts of template, 33 parts of unsaturated carboxylic acid monomer, 32 parts of oxidant, 9 parts of reducing agent, 1.2 parts of chain transfer agent, 4 parts of sodium hydroxide aqueous solution (mass concentration is 30%, calculated by mass of solution).

[0108] The molecular sieves are clinoptilolite molecular sieve and mordenite molecular sieve, and the mass ratio of each component is clinoptilolite molecular sieve:mordenite molecular sieve=5:4.

[0109] The template agent is vinyl polyoxyethylene ether, diethylene glycol monovinyl ether and diethylene glycol monoethyl ether, and the mass ratio of each component is vinyl polyoxyethylene ether: diethylene glycol monovinyl ether: diethylene glycol monoethyl ether=2:3:3.

[0110] Wherein, the unsaturated carboxylic acid monomer is acrylic acid.

[0111] The oxidants are sodium hypochlorite and hydrogen peroxide (mass concentration 30%), and the mass ratio of each component is sodium hypochlorite: hydrogen peroxide = 2.8:3.5.

[0112] Among them, the reducing agent is bleaching agent.

[0113] The chain transfer agent is mercaptopropionic acid and mercaptoethanol, and the mass ratio of each component is mercaptopropionic acid: mercaptoethanol=2.2:2.6.

[0114] The preparation method of the solid molecular sieve plasticizer is the same as that in Example 1.

[0115] Example 7

[0116] The raw materials for preparing the solid molecular sieve plasticizer provided in this embodiment are:

[0117] 350 parts of molecular sieve, 360 parts of template, 32 parts of unsaturated carboxylic acid monomer, 30 parts of oxidant, 9 parts of reducing agent, 1.2 parts of chain transfer agent, 4 parts of sodium hydroxide aqueous solution (mass concentration is 30%, calculated by mass of solution).

[0118] The molecular sieves are clinoptilolite molecular sieve and mordenite molecular sieve, and the mass ratio of each component is clinoptilolite molecular sieve:mordenite molecular sieve=6:3.5.

[0119] The template agent is vinyl polyoxyethylene ether, diethylene glycol monovinyl ether and diethylene glycol monoethyl ether, and the usage ratio of each component is vinyl polyoxyethylene ether: diethylene glycol monovinyl ether: diethylene glycol monoethyl ether=2:2.7:3.

[0120] The unsaturated carboxylic acid monomers are acrylic acid, hydroxyethyl acrylate and acryloyl chloride, and the mass ratio of the components is acrylic acid: acrylate: acryloyl chloride = 2.5:2.0:1.6.

[0121] Wherein, the oxidant is sodium hypochlorite.

[0122] The reducing agent is bleaching agent, ferrous sulfate and stannous sulfate, and the mass ratio of the components is bleaching agent: ferrous sulfate: stannous sulfate = 0.8:8.0:10.

[0123] The chain transfer agent is mercaptopropionic acid and mercaptoethanol, and the mass ratio of each component is mercaptopropionic acid: mercaptoethanol = 2.2:2.4.

[0124] The preparation method of the solid molecular sieve plasticizer is the same as that in Example 1.

[0125] Performance Testing

[0126] 1) Figure 1This is a physical picture of the molecular sieve plasticizer product prepared in Example 3; Figure 1 As shown, the molecular sieve plasticizer prepared by the present invention is in a solid powder state.

[0127] 2) When preparing C30 concrete, the mix ratio of C30 concrete is shown in Table 1, and the solid molecular sieve plasticizers prepared in Examples 1 to 7 are added respectively, and the workability of the concrete is adjusted to an initial slump of 220 mm, and the amount of the molecular sieve plasticizer is 2.5% (relative to cement). The slump loss of concrete over time is tested according to GB / T 50080-2016 "Standard for Test Methods for Performance of Ordinary Concrete Mixtures".

[0128] At the same time, C30 concrete without adding solid molecular sieve plasticizer was used as blank comparison. The results are shown in Table 2.

[0129] After forming and curing, the obtained concrete specimens were tested for strength at different ages in accordance with GB / T 50081-2019 “Standard for Test Methods for Physical and Mechanical Properties of Concrete”. The results are shown in Table 3.

[0130] Table 1 Concrete mix ratio (kg / m 3 )

[0131]

[0132] Table 2 Slump loss of different concrete over time (mm)

[0133] initial 1h 2h 3h Blank Contrast 220 208 196 169 Example 1 220 219 215 206 Example 2 220 218 214 204 Example 3 220 219 216 208 Example 4 220 218 212 202 Example 5 220 219 212 204 Example 6 220 218 210 200 Example 7 220 219 214 205

[0134] Table 3 Strength of concrete at different ages (MPa)

[0135]

[0136]

[0137] As shown in Tables 2 and 3, compared with C30 concrete without molecular sieve plasticizer, after adding the solid molecular sieve plasticizer prepared in Example 1, the slump loss of fresh C30 concrete after 1 hour is basically no loss; the slump after 2 hours is 215mm, and the slump loss after time is about 2.3%; the slump after 3 hours is 206mm, and the slump loss after time is about 6.4%, which fully meets the pumping requirements and has excellent performance. And after the concrete test blocks prepared by the plasticizer of this embodiment are formed and cured, the strength at each age meets the relevant construction requirements, and there is a certain increase compared with the blank.

[0138] Compared with C30 concrete without adding molecular sieve plasticizer, after adding the molecular sieve plasticizer prepared in Example 2, the slump loss of fresh C30 concrete after 1 hour is basically no loss; the slump after 2 hours is 214mm, and the slump loss after time is about 2.7%; the slump after 3 hours is 204mm, and the slump loss after time is about 7.3%, which fully meets the pumping requirements and has excellent performance. And after the concrete test blocks prepared by the plasticizer of this embodiment are formed and cured, the strength at each age meets the relevant construction requirements, and has a certain increase compared with the blank.

[0139] Compared with C30 concrete without molecular sieve plasticizer, after adding the solid molecular sieve plasticizer prepared in Example 3, the slump loss of fresh C30 concrete after 1 hour is basically no loss; the slump after 2 hours is 216mm, and the slump loss after time is about 1.8%; the slump after 3 hours is 208mm, and the slump loss after time is about 5.5%, which fully meets the pumping requirements and has excellent performance. And the concrete test blocks prepared by the plasticizer of this embodiment meet the relevant construction requirements after molding and curing, and have a certain increase compared with the blank.

[0140] Compared with C30 concrete without molecular sieve plasticizer, after adding the solid molecular sieve plasticizer prepared in Example 4, the slump loss of fresh C30 concrete after 1 hour is basically no loss; the slump after 2 hours is 212mm, and the slump loss after time is about 3.6%; the slump after 3 hours is 202mm, and the slump loss after time is about 8.2%, which fully meets the pumping requirements and has excellent performance. And the concrete test blocks prepared by the plasticizer of this embodiment meet the relevant construction requirements after molding and curing, and have a certain increase compared with the blank.

[0141] Compared with C30 concrete without adding molecular sieve plasticizer, after adding molecular sieve plasticizer prepared in Example 5, the slump loss of fresh C30 concrete after 1 hour is basically no loss; the slump after 2 hours is 212mm, and the slump loss after time is about 3.6%; the slump after 3 hours is 204mm, and the slump loss after time is about 7.3%, which fully meets the pumping requirements and has excellent performance. And the concrete test blocks prepared by using the plasticizer of this embodiment meet the relevant construction requirements after molding and curing, and have a certain increase compared with the blank.

[0142] Compared with C30 concrete without adding molecular sieve plasticizer, after adding the molecular sieve plasticizer prepared in Example 6, the slump loss of fresh C30 concrete after 1 hour is basically no loss; the slump after 2 hours is 210mm, and the slump loss after time is about 4.5%; the slump after 3 hours is 200mm, and the slump loss after time is about 9.1%, which fully meets the pumping requirements and has excellent performance. And the concrete test blocks prepared by the plasticizer of this embodiment meet the relevant construction requirements after molding and curing, and have a certain increase compared with the blank.

[0143] Compared with C30 concrete without adding molecular sieve plasticizer, after adding molecular sieve plasticizer prepared in Example 7, the slump loss of fresh C30 concrete after 1 hour is basically no loss; the slump after 2 hours is 214mm, and the slump loss after time is about 2.7%; the slump after 3 hours is 205mm, and the slump loss after time is about 6.8%, which fully meets the pumping requirements and has excellent performance. And the concrete test blocks prepared by using the plasticizer of this embodiment meet the relevant construction requirements after molding and curing, and have a certain increase compared with the blank.

[0144] It can be seen from the above embodiments that the solid molecular sieve plasticizer provided by the present invention solves the problem of the rapid loss of slump of fresh concrete over time, can effectively maintain the good flow properties of the concrete mixture for a long time, and brings convenience and possibility to the on-site construction and long-distance transportation of concrete. At the same time, compared with liquid products on the market, the solid molecular sieve plasticizer is a solid powder, non-toxic and harmless, and is more convenient for packaging, transportation and storage.

[0145] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A solid molecular sieve plasticizer, characterized in that: The preparation comprises the following raw materials in parts by weight: 300-400 parts of molecular sieves; 320-380 parts of templates; 22-40 parts of unsaturated carboxylic acid monomers; 20-40 parts of oxidants; 4-12 parts of reducing agents; 0.3-2 parts of chain transfer agents; and 2-10 parts of alkali reagents.

2. The solid molecular sieve plasticizer according to claim 1, characterized in that: The molecular sieve includes one or more of clinoptilolite molecular sieve and mordenite molecular sieve.

3. The solid molecular sieve plasticizer according to claim 1, characterized in that: The template agent includes one or more of vinyl polyoxyethylene ether, diethylene glycol monovinyl ether and diethylene glycol monoethyl ether.

4. The solid molecular sieve plasticizer according to claim 1, characterized in that: The unsaturated carboxylic acid monomers include one or more of acrylic acid, acrylic ester, acryloyl chloride and itaconic acid.

5. The solid molecular sieve plasticizer according to claim 1, characterized in that: The oxidant includes one or more of sodium hypochlorite, hydrogen peroxide and sodium percarbonate.

6. The solid molecular sieve plasticizer according to claim 1, characterized in that: The reducing agent includes one or more of bleaching powder, ferrous sulfate and stannous sulfate.

7. The solid molecular sieve plasticizer according to claim 1, characterized in that: The chain transfer agent includes one or more of mercaptopropionic acid, mercaptoethanol and sodium hypophosphite; the alkali reagent includes sodium hydroxide aqueous solution.

8. The method for preparing the solid molecular sieve plasticizer according to any one of claims 1 to 7, characterized in that: The following steps are involved: Mixing a template, an oxidant and water to obtain a first mixed material; Mixing a reducing agent, a chain transfer agent and water to obtain a second mixed material; The first mixed material, the second mixed material and an aqueous solution of an unsaturated carboxylic acid monomer are mixed, an alkali reagent is added, the pH value is adjusted to 5 to 7, and a polymerization reaction is carried out to obtain a high molecular polymer; The high molecular polymer is mixed with the molecular sieve for adsorption, and the obtained product is sequentially vacuum filtered and dried to obtain a solid molecular sieve plasticizer.

9. The preparation method according to claim 8, characterized in that: The polymerization reaction temperature is 15-25° C., and the time is 2.5-3.0 hours; the adsorption temperature is 15-25° C., and the time is 30-40 minutes.

10. Use of the solid molecular sieve plasticizer according to any one of claims 1 to 7 or the solid molecular sieve plasticizer prepared by the preparation method according to any one of claims 8 to 9 in concrete.

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