Polycarboxylate superplasticizer and preparation method thereof

Abstract

The invention relates to a polycarboxylate superplasticizer and a preparation method thereof. The invention relates to a preparation method of a polycarboxylic acid water reducer, which comprises the following steps: (1) mixing water at 20-25 DEG C with a polyether monomer, reacting for 25-30 minutes, adding hydrogen peroxide, and mixing for 8-12 minutes to obtain a material 1; (2) dropwise adding a mixed material A and a mixed material B into the material 1 at the temperature of 40-42 DEG C, after dropwise adding, carrying out heat preservation reaction at the temperature of 40-42 DEG C for 0.8-1.2 hours, supplementing water, and uniformly mixing to obtain a material 2; wherein in the dripping process, after the material A is dripped for 10 minutes, the material B is dripped; the material A comprises water and acrylic acid; the material B comprises water, sodium formaldehyde sulfoxylate and sodium hydrogen sulfite; and (3) adding sodium hypophosphite into the material 2, mixing for 8-12 minutes, adding ferrous sulfate, and mixing for 8-12 minutes to obtain the polycarboxylate superplasticizer. According to the polycarboxylic acid water reducing agent and the preparation method thereof, the process is simple, and the prepared water reducing agent is good in water reducing effect and high in adaptability to cement.

Description

Technical Field

[0001] The present invention belongs to the technical field of water reducing agents, and particularly relates to a polycarboxylate water reducing agent and a preparation method thereof. Background Art

[0002] In the preparation process of concrete, mortar and neat cement paste, a product that can change the properties of concrete, mortar or neat cement paste by adding a small amount (not exceeding 5% of the cement dosage) is called a concrete admixture. Adding an appropriate amount of admixture to concrete can improve the quality of concrete, improve the performance of concrete, reduce the water consumption of concrete, save cement, reduce costs, and speed up the construction progress. With the progress of technology, admixtures have become an essential material in addition to cement, fine and coarse aggregates, admixtures and water. Adding admixtures is an important measure for optimizing the design of concrete mix proportion and improving the durability of concrete.

[0003] A water reducing agent is a concrete admixture that can reduce the mixing water consumption under the condition of maintaining the basic unchanged slump of concrete. After the water reducing agent is added to the concrete mixture, it has a dispersing effect on cement particles, can improve its workability, reduce the unit water consumption, improve the fluidity of the concrete mixture; or reduce the unit cement dosage and save cement. However, the current water reducing agents have problems such as high energy consumption, large pollution, unsatisfactory water reducing effect, and poor adaptability to cement, which affect the quality of concrete and the construction efficiency.

[0004] In view of this, the present invention proposes a new water reducing agent and a preparation method thereof. This technical solution is green, environmentally friendly, energy-saving and emission-reducing, and the water reducing agent has a good water reducing effect. Summary of the Invention

[0005] The invention purpose of the present invention is to provide a preparation method of a polycarboxylate water reducing agent, and this preparation method has low energy consumption, is green and environmentally friendly.

[0006] In order to achieve the above purpose, the technical solution adopted is as follows:

[0007] A preparation method of a polycarboxylate water reducing agent includes the following steps:

[0008] (1) Mix water at 20 - 25°C with a polyether monomer and react for 25 - 30 minutes, then add hydrogen peroxide and mix for 8 - 12 minutes to obtain Material 1;

[0009] (2) At 40 - 42°C, dropwise add a mixture of Material A and Material B to the above-mentioned Material 1. After the dropping is completed, keep the temperature at 40 - 42°C and carry out a heat preservation reaction for 0.8 - 1.2 hours, then add water and mix evenly to obtain Material 2;

[0010] Among them, during the dropping process, after dropping Material A for 10 minutes, start dropping Material B;

[0011] The Material A includes water and acrylic acid;

[0012] The described Material B includes water, Rongalite, and sodium bisulfite;

[0013] (3) Add sodium hypophosphite to the described Material 2, mix for 8 - 12 minutes, then add ferrous sulfate and mix for 8 - 12 minutes to obtain the polycarboxylate water - reducing agent.

[0014] Furthermore, in the step (1), the mass ratio of water, polyether monomer, and hydrogen peroxide is 2800:3200 - 3400:36 - 40.

[0015] Still further, in the step (1), the mass ratio of water, polyether monomer, and hydrogen peroxide is 2800:3300:38.

[0016] Furthermore, in the step (2), the mass ratio of polyether monomer, water in Material A, acrylic acid in Material A, water in Material B, Rongalite in Material B, sodium bisulfite in Material B, and supplementary water is 3200 - 3400:350:400 - 460:1000:9 - 11:4.5 - 5.5:2000 - 2100.

[0017] Still further, in the step (2), the mass ratio of polyether monomer, water in Material A, acrylic acid in Material A, water in Material B, Rongalite in Material B, sodium bisulfite in Material B, and supplementary water is 3300:350:434:1000:10:5:2050.

[0018] Furthermore, in the step (3), the mass ratio of polyether monomer, sodium hypophosphite, and ferrous sulfate is 3200 - 3400:68 - 77:0.45 - 0.55.

[0019] Still further, in the step (3), the mass ratio of polyether monomer, sodium hypophosphite, and ferrous sulfate is 3300:72.5:0.5.

[0020] Furthermore, in the step (2), the dropping time of Material A does not exceed 3 hours, and the dropping time of Material B does not exceed 2.5 hours.

[0021] Another object of the present invention is to provide a polycarboxylate water - reducing agent prepared by the above - mentioned preparation method. This water - reducing agent has good water - reducing effect and strong adaptability to cement.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. The technical solution of the present invention uses raw materials such as polyether monomer, hydrogen peroxide, sodium hypophosphite, ferrous sulfate, acrylic acid, Rongalite, and sodium bisulfite. These raw materials are common, easy to obtain, and have low energy consumption.

[0024] 2. The technical solution of the present invention can accurately control the reaction time and temperature, save energy, be green, and is suitable for industrial production.

[0025] 3. The technical solution of the present invention prepares a polycarboxylate water reducer with good water reducing effect, strong adaptability to cement, high use value, and good application prospect. It is of great significance for realizing cost reduction and efficiency increase, as well as for the green and sustainable economic development. Detailed Embodiments

[0026] In order to further elaborate on a polycarboxylate water reducer and its preparation method according to the present invention to achieve the expected invention purpose, the following, in conjunction with preferred embodiments, details the specific embodiments, structures, features, and effects of a polycarboxylate water reducer and its preparation method proposed according to the present invention. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0027] Before elaborating in detail on a polycarboxylate water reducer and its preparation method according to the present invention, it is necessary to further explain the related materials mentioned in the present invention to achieve better effects.

[0028] Polyether monomers are mainly polymerized from ethylene oxide and other monomers. Currently, there are mainly three types in China: poly(ethylene glycol) monomethyl ether, allyl poly(ethylene oxide) ether, and methallyl poly(ethylene oxide) ether. Polyether monomers are mostly used in polycarboxylate water reducers for the construction industry, and water reducers are the downstream products of polyether monomers. Poly(ethylene glycol) monomethyl ether: used as a raw material for cement water reducers and enhancers in the building materials industry; allyl poly(ethylene oxide) ether: has good water solubility and will not hydrolyze and deteriorate, and is used as the main raw material in polycarboxylate-based cement water reducers; methallyl poly(ethylene oxide) ether: used as a solubilizer, etc., for the solubilization of oil substances.

[0029] Hydrogen peroxide, commonly known as an aqueous solution of hydrogen peroxide (colorless, odorless, transparent), is widely used as a strong oxidant and disinfectant in fields such as sterilization and disinfection, sewage treatment, dyeing and weaving, and bleaching. The synthesis of water reducers is a complex organic chemical reaction process that requires redox reactions to initiate monomer polymerization to generate high molecular polymers with specific structures and properties. In this process, hydrogen peroxide plays a key role. By providing oxidation ability to initiate the polymerization reaction, the synthesis reaction becomes more smooth, efficient, and controllable. At the same time, the use of hydrogen peroxide also simplifies the production process and reduces the production cost, providing important support for the production and application of water reducers.

[0030] Sodium hypophosphite, with the chemical formula NaH2PO2, is a white crystalline powder. It is easily soluble in hot ethanol and glycerol, soluble in water, and insoluble in ether. Sodium hypophosphite plays an important role in the synthesis of water reducing agents. By controlling the process of polymerization reaction and the distribution of molecular weight, the performance and quality of the product can be improved. During use, appropriate dosage and usage method need to be selected according to specific circumstances to ensure the stability and reliability of the product.

[0031] Ferrous sulfate is an inorganic compound with the chemical formula FeSO4. It appears as a white powder without odor. Its crystalline hydrate is a heptahydrate at room temperature, commonly known as "green vitriol", a light green crystal. It effloresces in dry air and is oxidized to brown basic ferric sulfate on the surface in humid air. It becomes a tetrahydrate at 56.6 °C and a monohydrate at 65 °C. Ferrous sulfate is soluble in water and almost insoluble in ethanol. Its aqueous solution oxidizes slowly in air when cold and more quickly when hot. The addition of alkali or exposure to light can accelerate its oxidation. Relative density (d15) 1.897. It is irritating. Ferrous sulfate can be used as a chromatographic analysis reagent, for the drop analysis determination of platinum, selenium, nitrite, and nitrate. Ferrous sulfate can also be used as a reducing agent, for manufacturing ferrite, water purification, polymerization catalyst, photoengraving, etc.

[0032] Acrylic acid is an organic compound, the simplest unsaturated fatty acid, with the chemical formula C3H4O2. It is a colorless, pungent-smelling liquid at room temperature and normal pressure. It is easily soluble in water (miscible), ethanol, ether, etc. Acrylic acid is mainly used for the preparation of acrylate, superabsorbent resin, etc., and is widely used in fields such as coatings, textiles, sanitary products, and water retention agents.

[0033] Rongalite, also known as sodium formaldehyde sulfoxylate, is prepared by combining formalin with sodium bisulfite and then reducing. Its chemical name is sodium hydroxymethanesulfinate, with the chemical formula CH2(OH)SO2Na. It is in the form of white blocks or crystalline powder, odorless or with a slight smell of Chinese chives; it is easily soluble in water and slightly soluble in alcohol. It is relatively stable at room temperature and has extremely strong reducibility at high temperatures, with a bleaching effect. It decomposes to release hydrogen sulfide when encountering acid, is stable when pH > 3, and is stable to alkali. It is often used as a discharging agent and reducing agent in the printing and dyeing industry for the production of indigo dyes, vat dyes, etc. The Rongalite used in this invention is powdered Rongalite.

[0034] Sodium bisulfite is an inorganic compound with the chemical formula NaHSO3. It is a white crystalline powder with an unpleasant smell of sulfur dioxide. It is easily soluble in water, the aqueous solution is acidic, and it is hardly soluble in alcohol. It is mainly used as a bleaching agent, preservative, antioxidant, and bacteriostatic agent.

[0035] After understanding the relevant materials mentioned in this invention, the following will further introduce in detail a polycarboxylate water reducing agent and its preparation method of this invention in combination with specific embodiments:

[0036] The technical solution of the present invention is as follows:

[0037] A preparation method of a polycarboxylate water reducer, comprising the following steps:

[0038] (1) Mix water at 20 - 25°C with a polyether monomer and react for 25 - 30 min, then add hydrogen peroxide and mix for 8 - 12 min to obtain Material 1;

[0039] (2) At 40 - 42°C, dropwise add a mixture of Material A and Material B to the above-mentioned Material 1. After the dropping is completed, keep the temperature at 40 - 42°C and react for 0.8 - 1.2 h, then add water and mix evenly to obtain Material 2;

[0040] Among them, during the dropping process, after dropping Material A for 10 min, start dropping Material B;

[0041] The said Material A includes water and acrylic acid;

[0042] The said Material B includes water, Rongalite, and sodium bisulfite;

[0043] (3) Add sodium hypophosphite to the above-mentioned Material 2, mix for 8 - 12 min, then add ferrous sulfate and mix for 8 - 12 min to obtain the water reducer.

[0044] In the above technical solution, the reaction mechanism is as follows:

[0045] The polycarboxylate water reducer is mainly obtained by copolymerizing unsaturated monomers under the action of an initiator to graft side-chain active groups onto the polymer main chain.

[0046] Start dropping Material B 10 min after dropping Material A first, in order to induce the initiator reaction first and prepare for the subsequent chain transfer reaction.

[0047] The dropping and mixing process of Material A and Material B is an exothermic reaction, and the temperature needs to be controlled at 40 - 42°C, which is more conducive to the combination of side-chain active groups and the polymer main chain, so as to achieve the maximum water reduction effect of the product.

[0048] Preferably, in the said step (1), the mass ratio of water, polyether monomer, and hydrogen peroxide is 2800:3200 - 3400:36 - 40.

[0049] More preferably, in the said step (1), the mass ratio of water, polyether monomer, and hydrogen peroxide is 2800:3300:38.

[0050] Preferably, in the step (2), the mass ratio of the polyether monomer, water in material A, acrylic acid in material A, water in material B, Rongalite in material B, sodium bisulfite in material B, and the supplementary water is 3200 - 3400: 350: 400 - 460: 1000: 9 - 11: 4.5 - 5.5: 2000 - 2100.

[0051] More preferably, in the step (2), the mass ratio of the polyether monomer, water in material A, acrylic acid in material A, water in material B, Rongalite in material B, sodium bisulfite in material B, and the supplementary water is 3300: 350: 434: 1000: 10: 5: 2050.

[0052] Preferably, in the step (3), the mass ratio of the polyether monomer, sodium hypophosphite, and ferrous sulfate is 3200 - 3400: 68 - 77: 0.45 - 0.55.

[0053] More preferably, in the step (3), the mass ratio of the polyether monomer, sodium hypophosphite, and ferrous sulfate is 3300: 72.5: 0.5.

[0054] Preferably, in the step (2), the dropping time of material A does not exceed 3 h, and the dropping time of material B does not exceed 2.5 h.

[0055] In the examples, each raw material is stored at room temperature for standby.

[0056] Example 1.

[0057] The specific operation steps are as follows:

[0058] (1) After adding 2800 kg of water at 24 °C into the reaction kettle, 3300 kg of polyether monomer is added, and they are stirred and mixed for reaction for 28 min. Then 38 kg of hydrogen peroxide is added and mixed for 10 min to obtain Material 1.

[0059] (2) The reaction kettle is adjusted to 41 °C, and the mixed materials A and B are dropped. After the dropping is completed, it is kept at 41 °C for heat preservation reaction for 1 h, and then 2050 kg of water is added and mixed evenly to obtain Material 2.

[0060] Among them, during the dropping process, after dropping material A for 10 min, material B starts to be dropped, and at this time, materials A and B are in the state of being dropped simultaneously. The dropping time of material A is 3 h, and the dropping time of material B is 2.5 h.

[0061] Material A is composed of 350 kg of water and 434 kg of acrylic acid; Material B is composed of 1000 kg of water, 10 kg of Rongalite, and 5 kg of sodium bisulfite.

[0062] (3) Add 72.5 kg of sodium hypophosphite to the reaction kettle. After mixing for 10 min, add 0.5 kg of ferrous sulfate and mix for 10 min to obtain the water reducing agent described above.

[0063] Example 2.

[0064] The specific operation steps are as follows:

[0065] (1) Add 2800 kg of water at 20 °C to the reaction kettle, then add 3200 kg of polyether monomer and stir and mix for reaction for 30 min. Then add 36 kg of hydrogen peroxide and mix for 8 min to obtain Material 1.

[0066] (2) Adjust the reaction kettle to 40 °C and drip-feed the mixed A and B materials. After the dripping is completed, keep the temperature at 40 °C for heat preservation reaction for 1.2 h, and then add 2000 kg of water and mix evenly to obtain Material 2.

[0067] Among them, during the dripping process, after dripping A material for 10 min, start dripping B material. At this time, A and B materials are in the state of being dripped simultaneously. The dripping time of A material is 2.8 h, and the dripping time of B material is 2.2 h.

[0068] A material is composed of 350 kg of water and 400 kg of acrylic acid; B material is composed of 1000 kg of water, 9 kg of Rongalite, and 4.5 kg of sodium bisulfite.

[0069] (3) Add 68 kg of sodium hypophosphite to the reaction kettle. After mixing for 8 min, add 0.45 kg of ferrous sulfate and mix for 8 min to obtain the water reducing agent described above.

[0070] Example 3.

[0071] The specific operation steps are as follows:

[0072] (1) Add 2800 kg of water at 25 °C to the reaction kettle, then add 3400 kg of polyether monomer and stir and mix for reaction for 25 min. Then add 40 kg of hydrogen peroxide and mix for 12 min to obtain Material 1.

[0073] (2) Adjust the reaction kettle to 42 °C and drip-feed the mixed A and B materials. After the dripping is completed, keep the temperature at 42 °C for heat preservation reaction for 0.8 h, and then add 2100 kg of water and mix evenly to obtain Material 2.

[0074] Among them, during the dripping process, after dripping A material for 10 min, start dripping B material. At this time, A and B materials are in the state of being dripped simultaneously. The dripping time of A material is 3 h, and the dripping time of B material is 2.5 h.

[0075] A material is composed of 350 kg of water and 460 kg of acrylic acid; B material is composed of 1000 kg of water, 11 kg of Rongalite, and 5.5 kg of sodium bisulfite.

[0076] (3) Add 77 kg of sodium hypophosphite to the reaction kettle. After mixing for 12 min, add 0.55 kg of ferrous sulfate and mix for 12 min to obtain the water reducer described above.

[0077] Example 4.

[0078] The specific operation steps are as follows:

[0079] (1) Add 2800 kg of water at 23 °C to the reaction kettle, then add 3250 kg of polyether monomer and stir and mix for reaction for 27 min. Then add 37 kg of hydrogen peroxide and mix for 9 min to obtain Material 1.

[0080] (2) Adjust the reaction kettle to 42 °C and drip-feed the mixed A and B materials. After the dripping is completed, keep the temperature at 41 °C for reaction for 1 h, and then add 2030 kg of water and mix evenly to obtain Material 2.

[0081] Among them, during the dripping process, after dripping A material for 10 min, start dripping B material. At this time, A and B materials are in the state of dripping simultaneously. The dripping time of A material is 3 h, and the dripping time of B material is 2.5 h.

[0082] A material is composed of 350 kg of water and 420 kg of acrylic acid; B material is composed of 1000 kg of water, 9.5 kg of Rongalite, and 4.8 kg of sodium bisulfite.

[0083] (3) Add 70 kg of sodium hypophosphite to the reaction kettle. After mixing for 9 min, add 0.48 kg of ferrous sulfate and mix for 9 min to obtain the water reducer described above.

[0084] Example 5.

[0085] The specific operation steps are as follows:

[0086] (1) Add 2800 kg of water at 24 °C to the reaction kettle, then add 3350 kg of polyether monomer and stir and mix for reaction for 28 min. Then add 39 kg of hydrogen peroxide and mix for 11 min to obtain Material 1.

[0087] (2) Adjust the reaction kettle to 41 °C and drip-feed the mixed A and B materials. After the dripping is completed, keep the temperature at 40 °C for reaction for 1 h, and then add 2080 kg of water and mix evenly to obtain Material 2.

[0088] Among them, during the dripping process, after dripping A material for 10 min, start dripping B material. At this time, A and B materials are in the state of dripping simultaneously. The dripping time of A material is 3 h, and the dripping time of B material is 2.5 h.

[0089] Component A is made by mixing 350 kg of water and 450 kg of acrylic acid; Component B is made by mixing 1000 kg of water, 10 kg of Rongalite, and 5.2 kg of sodium bisulfite.

[0090] (3) Add 75 kg of sodium hypophosphite to the reaction kettle. After mixing for 11 minutes, add 0.54 kg of ferrous sulfate and mix for 11 minutes to obtain the water reducing agent described.

[0091] Comparative Example 1.

[0092] The specific operation steps are as follows:

[0093] (1) Add 212 kg of water at 24 °C to the reaction kettle, then add 353 kg of polyether monomer and stir and mix for reaction for 28 minutes. Then add 3 kg of hydrogen peroxide and mix for 10 minutes to mix evenly to obtain Material 1.

[0094] (2) Heat the reaction kettle to 41 °C and drip Component A. The dripping time is 3 hours. After the dripping is completed, keep the temperature at 41 °C for heat preservation reaction for 1 hour, and then add 141 kg of water and mix evenly to obtain Water Reducing Agent 1.

[0095] Among them, Component A is made by mixing 247 kg of water, 42.5 kg of acrylic acid, 1.4 kg of mercaptopropionic acid, and 0.71 kg of Vc.

[0096] Comparative Example 2.

[0097] The specific operation steps are as follows:

[0098] (1) Add 352.6 kg of water at 24 °C to the reaction kettle, then add 352.6 kg of polyether monomer and stir and mix for reaction for 28 minutes. Then add 3.53 kg of ammonium persulfate and mix for 10 minutes to obtain Material 1.

[0099] (2) Adjust the reaction kettle to 41 °C and drip Component A. The dripping time is 3 hours. After the dripping is completed, keep the temperature at 41 °C for heat preservation reaction for 0.5 hour, and then add 141 kg of water and mix evenly to obtain Water Reducing Agent 2.

[0100] Among them, Component A is made by mixing 247 kg of water, 42.5 kg of acrylic acid, 1.48 kg of mercaptopropionic acid, and 0.53 kg of Vc.

[0101] Comparative Example 3.

[0102] The specific operation steps are as follows:

[0103] (1) Add 278 kg of water at 24 °C to the reaction kettle, then add 350 kg of polyether monomer and stir and mix for reaction for 28 minutes. Then add 6.4 kg of acrylic acid and 3.07 kg of hydrogen peroxide in sequence and mix for 10 minutes to obtain Material 1.

[0104] (2) Adjust the reactor to 41°C and add the mixed materials A and B dropwise. After the dropwise addition is completed, keep the reaction at 41°C for 1 h, then add 215 kg of water and mix evenly to obtain water reducer 3.

[0105] Among them, during the dropwise addition process, after adding material A for 10 min, start adding material B dropwise. At this time, materials A and B are in the state of being added dropwise simultaneously. The dropwise addition time of material A is 50 min, and the dropwise addition time of material B is 55 min.

[0106] Material A is composed of 41.7 kg of water and 33.3 kg of acrylic acid; material B is composed of 69.5 kg of water, 0.6 kg of Vc, and 1.67 kg of mercaptopropionic acid.

[0107] Comparative Example 4.

[0108] The specific operation steps are as follows:

[0109] (1) After adding 300 kg of water at 24°C to the reactor, add 300 kg of polyether monomer and stir and mix for reaction for 28 min. Then add 4.5 kg of sodium hypophosphite, 3 kg of hydrogen peroxide, and 0.2 kg of 1 wt% ferrous solution, and mix evenly to obtain material 1.

[0110] (2) Adjust the reactor to 41°C and add the mixed materials A and B dropwise. After the dropwise addition is completed, keep the reaction at 41°C for 1 h, then add water to 1000 kg and mix evenly to obtain water reducer 4.

[0111] Among them, during the dropwise addition process, after adding material A for 10 min, start adding material B dropwise. At this time, materials A and B are in the state of being added dropwise simultaneously. The dropwise addition time of material A is 50 min, and the dropwise addition time of material B is 55 min.

[0112] Material A is composed of 60 kg of water and 45 kg of acrylic acid; material B is composed of 80 kg of water, 1 kg of Rongalite, and 0.5 kg of sodium bisulfite.

[0113] Comparative Example 5.

[0114] The specific operation steps are as follows:

[0115] (1) After adding 290 kg of water at 24°C to the reactor, add 340 kg of polyether monomer and stir and mix for reaction for 28 min. Then add 4.5 kg of sodium hypophosphite, 3 kg of hydrogen peroxide, and 0.2 kg of 1 wt% ferrous solution, and mix evenly to obtain material 1.

[0116] (2) Adjust the reactor to 41°C and add the mixed materials A and B dropwise. After the dropwise addition is completed, keep the reaction at 41°C for 1 h, then add water to 1000 kg and mix evenly to obtain water reducer 5.

[0117] Among them, during the dropping process, after dropping Material A for 10 minutes, start dropping Material B. At this time, Materials A and B are in the state of being dropped simultaneously. The dropping time of Material A is 50 minutes, and the dropping time of Material B is 55 minutes.

[0118] Material A is made by mixing 65 kg of water and 40 kg of acrylic acid; Material B is made by using 80 kg of water, 1 kg of Rongalite, and 0.5 kg of sodium bisulfite.

[0119] Example 6.

[0120] Compare the mother liquor performance of Example 1 with Comparative Examples 1 - 5.

[0121] (1) Cement paste fluidity test

[0122] Use the conventional method in this field (according to the standards: JCT729 - 2005, GB - T1346 - 2024) to test the cement paste fluidity test.

[0123] The superplasticizer numbers 1 - 6 correspond to the superplasticizers 1 - 5 prepared in Comparative Examples 1 - 5 and the superplasticizer prepared in Example 1 (i.e., superplasticizer 6) respectively.

[0124] The cement paste mix ratio is shown in Table 1, the superplasticizer solution mix ratio is shown in Table 2, and the experimental data are shown in Table 3.

[0125] Table 1

[0126] Cement Water Water reducing agent solution (2.0 wt% dosage) 300 87 6

[0127] Table 2

[0128] Water reducing agent Water 190 810

[0129] Table 3

[0130] Water reducing agent number 1 2 3 4 5 6 Initial fluidity of neat cement paste 200 200 200 205 210 210 Fluidity of neat cement paste after 1 hour 210 210 220 210 220 230 Fluidity of neat cement paste after 2 hours 210 210 210 210 220 230

[0131] Conclusion: On the premise of ensuring quality, the six processes are gradually advanced. At present, the superplasticizer prepared in Example 1 has extremely high cost - performance and obvious performance advantages, and has more competitive advantages in the market.

[0132] (2) Concrete test

[0133] Use the six kinds of cements prepared in the (1) cement paste fluidity test to prepare concrete. The concrete mix ratio is shown in Table 4.

[0134] Table 4

[0135] Reference cement Sand Large aggregate Small aggregate Water Admixture 360 824 704 302 153 3.6

[0136] Note: The reference cement is the six kinds of cements prepared in the (1) cement paste fluidity test.

[0137] Six kinds of concrete were compared using conventional methods in the art (in accordance with GB-T50080-2016 "Standard Test Method for Properties of Ordinary Concrete Mixtures") to conduct slump / spread tests, and the data are shown in Table 5.

[0138] Table 5

[0139]

[0140] Conclusion: With the optimization of the performance of the water reducer, it is more conducive to the gradual improvement of the workability such as the plasticity of concrete. Specifically in terms of slump and spread, the water reducer of the present invention is the most cost-effective at the present stage.

[0141] The above are only the preferred embodiments of the embodiments of the present invention, and do not impose any formal restrictions on the embodiments of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the embodiments of the present invention still fall within the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A preparation method of a polycarboxylate water reducer, characterized in that It includes the following steps: (1) Mix water at 20 - 25°C with polyether monomer and react for 25 - 30 min, then add hydrogen peroxide and mix for 8 - 12 min to obtain Material 1; (2) At 40 - 42°C, dropwise add mixed Material A and Material B to the above-mentioned Material 1. After the dropping is completed, keep the temperature at 40 - 42°C and react for 0.8 - 1.2 h, then add water and mix evenly to obtain Material 2; Among them, during the dropping process, after dropping Material A for 10 min, start dropping Material B; The said Material A includes water and acrylic acid; The said Material B includes water, Rongalite, and sodium bisulfite; (3) Add sodium hypophosphite to the above-mentioned Material 2, mix for 8 - 12 min, then add ferrous sulfate and mix for 8 - 12 min to obtain the polycarboxylate water reducer.

2. The preparation method according to claim 1, characterized in that, In the said step (1), the mass ratio of water, polyether monomer, and hydrogen peroxide is 2800:3200 - 3400:36 - 40.

3. The preparation method according to claim 2, characterized in that, In the said step (1), the mass ratio of water, polyether monomer, and hydrogen peroxide is 2800:3300:

38.

4. The preparation method according to claim 1, characterized in that, In the said step (2), the mass ratio of polyether monomer, water in Material A, acrylic acid in Material A, water in Material B, Rongalite in Material B, sodium bisulfite in Material B, and added water is 3200 - 3400:350:400 - 460:1000:9 - 11:4.5 - 5.5:2000 - 2100.

5. The preparation method according to claim 4, characterized in that, In the said step (2), the mass ratio of polyether monomer, water in Material A, acrylic acid in Material A, water in Material B, Rongalite in Material B, sodium bisulfite in Material B, and added water is 3300:350:434:1000:10:5:2050.

6. The preparation method according to claim 1, characterized in that, In the said step (3), the mass ratio of polyether monomer, sodium hypophosphite, and ferrous sulfate is 3200 - 3400:68 - 77:0.45 - 0.

55.

7. The preparation method according to claim 6, characterized in that, In the said step (3), the mass ratio of polyether monomer, sodium hypophosphite, and ferrous sulfate is 3300:72.5:0.

5.

8. The preparation method according to claim 1, characterized in that, In the said step (2), the dropping time of Material A does not exceed 3 h, and the dropping time of Material B does not exceed 2.5 h.

9. A polycarboxylate water reducer, characterized in that, Prepared by using the preparation method described in any one of claims 1 - 8.

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