A non-collapse super-sustained release water reducer mother liquor and its preparation process

Abstract

This application belongs to the technical field of water reducer preparation, and particularly relates to a super slow-release water reducer mother liquor without slump loss and its preparation process. The super slow-release water reducer mother liquor is obtained by copolymerizing a phosphoric acid-based functional monomer, an amide-based functional monomer, a polyether monomer, and an unsaturated carboxylic acid; functional groups such as amide groups and ester groups introduced on the molecular chain of the water reducer will slowly hydrolyze into anionic anchoring groups such as carboxyl groups in an alkaline environment, thereby promoting the secondary adsorption of the water reducer to cement particles, making it have a longer slump retention performance and higher compressive strength.

Description

Technical Field

[0001] This application belongs to the technical field of water reducer preparation, and particularly relates to a super slow-release water reducer mother liquor without slump loss and its preparation process. Background Art

[0002] Concrete is a composite material composed of a gelling medium, aggregate particles and fragments. Due to its low price, easy availability, good water resistance, plasticity and fluidity, it is highly favored by engineers and has become one of the most important materials in the civil engineering industry. With the progress of science and the development of the times, the utilization rate of concrete is continuously increasing, and higher requirements are placed on the performance of concrete. As is well known, excellent performance depends on high-quality materials. At present, the continuous exploitation and utilization of high-quality sand and gravel aggregates have led to the scarcity of high-quality materials and difficult material acquisition. In order to improve the performance of concrete, research must be carried out on concrete admixtures to promote the development of the concrete industry.

[0003] As the third-generation high-performance water reducer, polycarboxylate-based water reducers have become the most widely used type of water reducer in concrete due to their advantages of low preparation cost, high water reduction rate, environmental friendliness and multi-functionality. Polycarboxylate water reducers are comb-shaped copolymers with hydrophilic anchoring groups such as carboxyl groups in the main chain and grafted polyoxyethylene side chains. Its structure mainly includes two parts. The main chain mainly plays an adsorption role, and is adsorbed on the surface of cement particles through the charge interaction between negative ion groups such as carboxyl groups and sulfonic acid groups and the surface charge of cement particles. The side chain is a hydrophilic long chain, which hinders the mutual adhesion between particles through steric hindrance, and this effect does not weaken with the extension of time. In recent years, the high-performance and green requirements of concrete have promoted the functionalization and green development of water reducers. Therefore, the research on functional polycarboxylate water reducers will play a crucial role in the development of the concrete industry.

[0004] The Chinese patent with the publication number CN109796561B discloses an aromatic ring-based polycarboxylate water reducer mother liquor, its preparation method and application. It is prepared by the quaternary copolymerization reaction of aryl conjugate unsaturated carboxylic acid, unsaturated functional monomer, unsaturated fatty carboxylic acid and isopentenyl polyoxyethylene ether macromonomer. The selected aryl conjugate unsaturated carboxylic acid itself has antibacterial and anticorrosive properties, so that the copolymer side chain structure has mildew and antibacterial functional groups, which can play a mildew and antibacterial role during the storage of the water reducer. At the same time, the aryl group also has a large steric hindrance, effectively slowing down the adsorption of the carboxyl groups released in the early stage of the water reducer by cement particles, so as to play a slow-release role and enhance the slump retention ability of concrete. The Chinese patent with the publication number CN118063127B discloses a polycarboxylate water reducer, its preparation method and application. It is prepared by reacting raw materials such as polycarboxylate water reducer mother liquor, hydroxypropyl methylcellulose, polysilicate ferric aluminum sulfate, organic anhydride, phosphorus-doped polyaniline / graphene composite material, defoamer and water. Using polysilicate ferric aluminum sulfate and hydroxypropyl methylcellulose to pretreat the polycarboxylate water reducer mother liquor can utilize the electrostatic repulsion between the functional groups of polysilicate ferric aluminum sulfate and hydroxypropyl methylcellulose to assist the dispersion of particles in the polycarboxylate water reducer mother liquor, avoiding the aggregation of particles in the water reducer and affecting the fluidity of the concrete slurry; through the surface modification of graphene with polyaniline, the dispersion and chemical stability of graphene are effectively improved, so that graphene is evenly dispersed in the polycarboxylate water reducer mother liquor, and can better isolate and disperse the particles in the polycarboxylate water reducer mother liquor, further preventing the aggregation between particles. However, the above modifications are all to directly compound the raw materials. Although it can alleviate the loss of concrete slump to a certain extent, in the face of the increasing performance requirements of concrete, higher requirements are put forward for the performance of the water reducer. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides a non-slump loss and ultra-slow release type water reducer mother liquor and its preparation process. The ultra-slow release type water reducer mother liquor is obtained by copolymerizing a phosphoric acid-based functional monomer, an amide-based functional monomer, a polyether monomer and an unsaturated carboxylic acid, which can improve the slump retention performance of the water reducer mother liquor and has higher compressive strength.

[0006] The technical solutions adopted by the present invention to solve the above technical problems are as follows:

[0007] A preparation process of a non-slump loss and ultra-slow release type water reducer mother liquor includes the following steps:

[0008] S100: Using raw materials including polyphosphoric acid and epoxy ester compounds, through an epoxy ring-opening reaction to obtain a phosphoric acid-based functional monomer;

[0009] S200: Using raw materials including aliphatic compounds and unsaturated carboxylic acids, through an acylation reaction to obtain an amide-based functional monomer;

[0010] The super slow-release water reducer mother liquor is obtained by copolymerizing S300, a phosphoric acid-based functional monomer, an amide-based functional monomer, a polyether monomer, and an unsaturated carboxylic acid.

[0011] As one of the most important chemical admixtures, water reducers can be adsorbed on the surface of cementitious material particles when added to the cementitious material, destroying the flocculent structure between the particles and playing a role in reducing water consumption. Polycarboxylate water reducers have the characteristics of low output, high water reduction rate, and good slump retention. Adding them to cement concrete can reduce the amount of mixing water, improve the workability and plasticity of the concrete, and endow the concrete with excellent mechanical properties and durability. However, with the increase in applications, the compatibility problems between them and concrete have gradually emerged. Therefore, in the present invention, a polycarboxylate water reducer modified with phosphorus groups and amide groups is obtained by copolymerizing a phosphoric acid-based functional monomer, an amide-based functional monomer, and an unsaturated carboxylic acid, making it have better dispersibility and a stronger retarding effect on cement.

[0012] Further, S100 specifically includes: mixing phytic acid with dimethyl sulfoxide and reacting at 45 - 60 °C for 25 - 45 min, then adding a mixture of glycidyl methacrylate and dimethyl sulfoxide thereto, and reacting at a constant temperature for 45 - 55 h after the addition is completed to obtain the phosphoric acid-based functional monomer; wherein, the preparation process of the mixture is: adding glycidyl methacrylate to dimethyl sulfoxide and stirring evenly to obtain it; the mass ratio of glycidyl methacrylate to dimethyl sulfoxide is 1 - 1.5:10; the mass ratio of phytic acid, dimethyl sulfoxide, and the mixture is 4.5 - 6.5:11 - 12:40 - 60; and the mixture of glycidyl methacrylate and dimethyl sulfoxide is added in a dropwise manner.

[0013] In this step, phytic acid and glycidyl methacrylate are used as raw materials, and a polyphosphoric acid chemical bond is bonded to glycidyl methacrylate through epoxy ring opening to prepare a phosphoric acid-based functional monomer. As an anionic group, introducing a phosphorus-containing group into the molecular structure of a polycarboxylate superplasticizer as an anchoring group can enhance its binding ability with calcium ions, making the prepared polycarboxylate superplasticizer molecules more likely to adsorb onto the surface of cement particles and further improving its dispersion performance. At the same time, the six-membered ring contained in phytic acid has a relatively large steric hindrance compared to the straight-chain molecular structure, which can effectively improve the anti-clay effect of the polycarboxylate superplasticizer and reduce the adsorption amount on bentonite. The polycarboxylate superplasticizer is sensitive to the clay content in sand and gravel aggregates. On the one hand, clay will competitively adsorb the polycarboxylate superplasticizer. On the other hand, the polyether side chain of the polycarboxylate superplasticizer can intercalate into the interlayer structure of clay, resulting in ineffective adsorption of the polycarboxylate superplasticizer and reducing the water-reducing and slump-keeping performance of the polycarboxylate superplasticizer. Since the adsorption ability of the phosphate group is stronger than that of the carboxyl group, it can adsorb onto the cement particles faster. In addition, the charge density of the phosphate group is higher than that of the carboxyl group. As the superplasticizer adsorbs onto the surface of cement particles, mutual repulsion reactions will occur between the same charges on the material surface, resulting in a decrease in the adsorption amount on the cement particles. In addition, calcium phosphate is insoluble in water, and covering the surface of cement particles can hinder the further adsorption of the superplasticizer on the surface of cement particles, improving the clay tolerance of the polycarboxylate superplasticizer containing a phosphate group.

[0014] Further, S200 specifically includes: under an inert atmosphere, ethyl 6-aminohexanoate, acrylic acid, and an inhibitor are mixed evenly, the temperature is raised to 65 - 85 °C and reacted for 2 - 4 h to obtain an amide-based functional monomer; where the inert atmosphere is a nitrogen atmosphere; the inhibitor is hydroquinone; the mass ratio of ethyl 6-aminohexanoate, acrylic acid, and the inhibitor is 1:1.8 - 2.8:0.03 - 0.06.

[0015] In this step, ethyl 6-aminohexanoate and acrylic acid are used as raw materials, and an amide-based functional monomer is obtained through an acylation reaction. Ordinary Portland cement is mainly composed of four chemical components: calcium oxide, silicon dioxide, iron(III) oxide, and aluminum(III) oxide. During the hydration process of cement, alkaline substances are generated, making the cement paste in an alkaline environment. Through the amidation reaction, amide groups and ester groups are introduced into the molecular chain of the polycarboxylate superplasticizer. The functional groups such as ester groups and amide groups carried by it will slowly hydrolyze into anionic anchoring groups such as carboxyl groups in an alkaline environment, thus promoting the second adsorption of the superplasticizer molecules onto the cement particles, so that it has a long slump-keeping performance.

[0016] Further, S300 specifically includes: adding methyl allyl polyoxyethylene ether and deionized water into a reactor, stirring at 25 - 30 °C until completely dissolved, then adding a phosphoric acid-based functional monomer and an amide-based functional monomer thereto. After mixing evenly, heating is stopped. Then, hydrogen peroxide and acrylic acid are added thereto, and after stirring evenly, an aqueous vitamin C solution and 3-mercaptopropionic acid are added thereto. After the addition is completed, the reaction is carried out at a constant temperature for 1.5 - 3 h. After the reaction is completed, the pH is adjusted to 5 - 6, and it is cooled to room temperature to obtain the super slow-release water reducer mother liquor; the preparation process of the aqueous vitamin C solution is: dissolving vitamin C in deionized water and stirring until dissolved, thus obtaining it; the dosage of vitamin C in deionized water is 0.006 - 0.01 g / mL.

[0017] The carboxyl groups contained in the polycarboxylate water reducer can act as slump retention groups. During the mixing process with cement particles, the anionic groups in the polycarboxylate molecules can combine with the cationic ions of the cement particles, enabling the polycarboxylate water reducer to be anchored on the surface of the cement particles, resulting in a reduction in the number of cations and a slower rate of combination of anions and cations, which to a certain extent inhibits the hydration of cement and plays a slump retention role. During the preparation process of the polycarboxylate water reducer, the introduction of the phosphoric acid-based functional monomer can form a complex with inorganic substances, thereby affecting the hydration reaction, and its strong complexing and adsorption capabilities exhibit strong dispersion performance; in addition, the introduction of the amide-based functional monomer enables the polycarboxylate water reducer molecules to slowly hydrolyze into anchoring groups such as carboxyl groups in an alkaline environment, prompting the water reducer molecules to perform secondary adsorption on the cement particles, making it have good slow-release performance. In addition, after modification with the phosphoric acid-based functional monomer and the amide-based functional monomer, the synergistic effect between nitrogen and phosphorus contained in the polycarboxylate molecular chain promotes the self-detachment of phosphoric acid protons and assists in the formation of a continuous hydrogen bond network between phosphoric acid molecules, generating a large steric hindrance and promoting the dispersion between cement particles. In addition, the long-chain molecules of methyl allyl polyoxyethylene ether can form a molecular adsorption layer in the aqueous phase, form an interfacial layer between water and the solid phase, effectively maintain the relative stability between cement particles, and maintain their fluidity; at the same time, it can also form hydrogen bonds with water, reduce the adhesion between water and the surface of cement particles, and play a water-reducing role; hydrogen bonds can be formed between its molecular chains, enabling its molecules to adhere to each other and form a dense molecular network structure, playing a role in enhancing the compressive and crack resistance of cement.

[0018] The present invention also provides a slump-loss-free super slow-release water reducer mother liquor, and the super slow-release water reducer mother liquor is obtained by using the preparation process of the slump-loss-free super slow-release water reducer mother liquor according to any one of the above technical solutions.

[0019] The present invention has the following beneficial effects:

[0020] A phosphoric acid-based functional monomer was prepared by using phytic acid and glycidyl methacrylate as raw materials and bonding polyphosphoric acid to glycidyl methacrylate through epoxy ring opening. Introducing a phosphorus-containing group into the molecular structure of the polycarboxylate superplasticizer as an anchoring group can enhance its binding ability with calcium ions, making the prepared polycarboxylate superplasticizer molecules more likely to adsorb onto the surface of cement particles, further improving its dispersion performance. At the same time, the six-membered ring contained in phytic acid has a large steric hindrance compared with the linear molecular structure, which can effectively improve the anti-clay effect of the polycarboxylate superplasticizer and reduce the adsorption amount on bentonite. An amide-based functional monomer was obtained by acylating 6-aminoethyl caproate and acrylic acid as raw materials. The functional groups such as ester groups and amide groups carried by it will slowly hydrolyze into anionic anchoring groups such as carboxyl groups in an alkaline environment, thereby promoting the second adsorption of the superplasticizer molecules to cement particles, so that it has a long slump retention performance. Detailed implementation manners

[0021] The following will describe clearly and completely the technical solutions in the embodiments of the present application in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0022] The phytic acid (Shanghai Test, biochemical reagent BR), dimethyl sulfoxide (analytical pure), glycidyl methacrylate (Alfa-L11133, 97%), 6-aminoethyl caproate (Alfa-H50296, 98%), 3-mercaptopropionic acid (Acros-C12553) used in the present invention were purchased from Sinopharm Chemical Reagent Co., Ltd. Acrylic acid (industrial grade, purity 99.24%), methallyl polyoxyethylene ether (Oak Chemical Co., Ltd., molecular weight 2400), hydrogen peroxide (industrial grade, main content 27.56%), vitamin C (industrial grade, main content 99.89%). All reagents are commercially available.

[0023] Example 1

[0024] A preparation process for a non-slump-loss ultra-slow-release superplasticizer mother liquor includes the following steps:

[0025] S100. Use raw materials including polyphosphoric acid and epoxy ester compounds to obtain phosphoric acid-based functional monomers through an epoxy ring-opening reaction. Specifically: Mix phytic acid with dimethyl sulfoxide and react at 55°C for 35 minutes, then add a mixture of glycidyl methacrylate and dimethyl sulfoxide thereto. After the addition is completed, react at a constant temperature of 55°C for 52 hours to obtain phosphoric acid-based functional monomers. Among them, the preparation process of the mixture is: Add glycidyl methacrylate to dimethyl sulfoxide and stir evenly to obtain it; the mass ratio of glycidyl methacrylate to dimethyl sulfoxide is 1.2:10; the mass ratio of phytic acid, dimethyl sulfoxide, and the mixture is 5.5:11.2:48; among them, the mixture of glycidyl methacrylate and dimethyl sulfoxide is added in a dropwise manner.

[0026] S200. Use raw materials including aliphatic compounds and unsaturated carboxylic acids to obtain amide-based functional monomers through an acylation reaction. Specifically: Under a nitrogen atmosphere, mix ethyl 6-aminohexanoate, acrylic acid, and the polymerization inhibitor hydroquinone evenly, raise the temperature to 75°C and react for 3 hours to obtain amide-based functional monomers. Among them, the mass ratio of ethyl 6-aminohexanoate, acrylic acid, and the polymerization inhibitor is 1:2.2:0.04.

[0027] S300. Copolymerize the phosphoric acid-based functional monomers, amide-based functional monomers, polyether monomers, and unsaturated carboxylic acids to obtain the super slow-release water reducer mother liquor. Specifically: Add 120 parts by weight of methallyl polyoxyethylene ether and 110 parts by weight of deionized water to a reactor and stir at 30°C until completely dissolved, then add 52 parts by weight of phosphoric acid-based functional monomers and 45 parts by weight of amide-based functional monomers thereto. After mixing evenly, stop heating, then add 3 parts by weight of hydrogen peroxide and 20 parts by weight of acrylic acid thereto, stir evenly, then add 16 parts by weight of vitamin C aqueous solution and 3 parts by weight of 3-mercaptopropionic acid. After the addition is completed, react at a constant temperature of 30°C for 2 hours. After the reaction is completed, adjust the pH to 5 - 6 with 30% sodium hydroxide solution, and cool to room temperature to obtain the super slow-release water reducer mother liquor. Among them, the preparation process of the vitamin C aqueous solution is: Dissolve vitamin C in deionized water and stir until dissolved to obtain it; the dosage of vitamin C in deionized water is 0.008 g / mL.

[0028] Example Two

[0029] This example is different from Example One as follows:

[0030] In step S100, mix phytic acid with dimethyl sulfoxide and react at 45°C for 25 minutes, then add a mixture of glycidyl methacrylate and dimethyl sulfoxide thereto. After the addition is completed, react at a constant temperature of 45°C for 45 hours; the mass ratio of glycidyl methacrylate to dimethyl sulfoxide is 1:10; the mass ratio of phytic acid, dimethyl sulfoxide, and the mixture is 4.5:11:40.

[0031] In step S200, ethyl 6 - aminocaproate, acrylic acid, and the polymerization inhibitor hydroquinone are mixed evenly, and the temperature is raised to 65 °C for reaction for 2 h; the mass ratio of ethyl 6 - aminocaproate, acrylic acid, and the polymerization inhibitor is 1:1.8:0.03.

[0032] In step S300, 90 parts by weight of allyl polyoxyethylene ether and 85 parts by weight of deionized water are added to the reactor and stirred at 25 °C until completely dissolved. Then, 28 parts by weight of a phosphoric acid - type functional monomer and 22 parts by weight of an amide - type functional monomer are added thereto. After mixing evenly, heating is stopped. Then, 0.8 part by weight of hydrogen peroxide and 12 parts by weight of acrylic acid are added thereto, and after stirring evenly, 14 parts by weight of an aqueous vitamin C solution and 1 part by weight of 3 - mercaptopropionic acid are added. After the addition is completed, the reaction is carried out at a constant temperature of 25 °C for 1.5 h. After the reaction is completed, the pH is adjusted to 5 - 6 with a 30% sodium hydroxide solution, and it is cooled to room temperature to obtain a super - slow - release water - reducing agent mother liquor; the dosage of vitamin C in deionized water is 0.006 g / mL.

[0033] Example Three

[0034] This example is different from Example One as follows:

[0035] In step S100, phytic acid and dimethyl sulfoxide are mixed and reacted at 60 °C for 45 min. Then, a mixed solution of glycidyl methacrylate and dimethyl sulfoxide is added thereto. After the addition is completed, the reaction is carried out at a constant temperature of 60 °C for 55 h; the mass ratio of glycidyl methacrylate to dimethyl sulfoxide is 1.5:10; the mass ratio of phytic acid, dimethyl sulfoxide, and the mixed solution is 6.5:12:60.

[0036] In step S200, ethyl 6 - aminocaproate, acrylic acid, and the polymerization inhibitor hydroquinone are mixed evenly, and the temperature is raised to 85 °C for reaction for 4 h; the mass ratio of ethyl 6 - aminocaproate, acrylic acid, and the polymerization inhibitor is 1:2.8:0.06.

[0037] In step S300, 150 parts by weight of allyl polyoxyethylene ether and 150 parts by weight of deionized water are added to the reactor and stirred at 30 °C until completely dissolved. Then, 80 parts by weight of a phosphoric acid - type functional monomer and 72 parts by weight of an amide - type functional monomer are added thereto. After mixing evenly, heating is stopped. Then, 5 parts by weight of hydrogen peroxide and 28 parts by weight of acrylic acid are added thereto, and after stirring evenly, 20 parts by weight of an aqueous vitamin C solution and 6 parts by weight of 3 - mercaptopropionic acid are added. After the addition is completed, the reaction is carried out at a constant temperature of 30 °C for 3 h. After the reaction is completed, the pH is adjusted to 5 - 6 with a 30% sodium hydroxide solution, and it is cooled to room temperature to obtain a super - slow - release water - reducing agent mother liquor; the dosage of vitamin C in deionized water is 0.01 g / mL.

[0038] Comparative Example 1

[0039] Compared with Example 1, in this comparative example, aminotrimethylenephosphonic acid was used as the polyphosphoric acid for the preparation of the phosphoric acid-based functional monomer, and the rest was referred to Example 1.

[0040] S100. Mix aminotrimethylenephosphonic acid and dimethyl sulfoxide and react at 55 °C for 35 min. Then add the mixed solution of glycidyl methacrylate and dimethyl sulfoxide thereto. After the addition is completed, keep the temperature at 55 °C and react for 52 h to obtain the phosphoric acid-based functional monomer; wherein, the preparation process of the mixed solution is: add glycidyl methacrylate to dimethyl sulfoxide and stir evenly to obtain; the mass ratio of glycidyl methacrylate to dimethyl sulfoxide is 1.2:10; the mass ratio of aminotrimethylenephosphonic acid, dimethyl sulfoxide and the mixed solution is 2.5:11.2:48; the mixed solution of glycidyl methacrylate and dimethyl sulfoxide is added dropwise.

[0041] The remaining steps are referred to Example 1.

[0042] Comparative Example 2

[0043] Compared with Example 1, in this comparative example, n-hexylamine was used as the aliphatic compound for the preparation of the amide-based functional monomer, and the rest was referred to Example 1.

[0044] S200. Under a nitrogen atmosphere, mix n-hexylamine, acrylic acid and the inhibitor hydroquinone evenly, raise the temperature to 75 °C and react for 3 h to obtain the amide-based functional monomer; wherein, the mass ratio of n-hexylamine, acrylic acid and the inhibitor is 0.67:2.2:0.04.

[0045] The remaining steps are referred to Example 1.

[0046] Comparative Example 3

[0047] Compared with Example 1, in this comparative example, the phosphoric acid-based functional monomer was not added during the preparation process of the water reducer mother liquor, and the rest was referred to Example 1.

[0048] The preparation process of the water reducing agent mother liquor is as follows: Add 120 parts by weight of methyl allyl polyoxyethylene ether and 110 parts by weight of deionized water into a reactor, stir at 30 °C until completely dissolved, then add 45 parts by weight of amide functional monomer thereto. After mixing evenly, stop heating, then add 2.2 parts by weight of hydrogen peroxide and 12 parts by weight of acrylic acid thereto, stir evenly, then add 12 parts by weight of vitamin C aqueous solution and 2.2 parts by weight of 3-mercaptopropionic acid. After the addition is completed, react at a constant temperature of 30 °C for 2 h. After the reaction is completed, adjust the pH to 5-6 with 30% sodium hydroxide solution, cool to room temperature to obtain the water reducing agent mother liquor; the preparation process of the vitamin C aqueous solution is: dissolve vitamin C in deionized water and stir until dissolved, then obtain it; the dosage of vitamin C in deionized water is 0.008 g / mL.

[0049] The amide functional monomer refers to the preparation of the amide functional monomer in Example 1.

[0050] Comparative Example 4

[0051] Compared with Example 1, in the preparation process of the water reducing agent mother liquor in this comparative example, no amide functional monomer is added, and the rest refers to Example 1.

[0052] The preparation process of the water reducing agent mother liquor is as follows: Add 120 parts by weight of methyl allyl polyoxyethylene ether and 110 parts by weight of deionized water into a reactor, stir at 30 °C until completely dissolved, then add 52 parts by weight of phosphoric acid functional monomer thereto. After mixing evenly, stop heating, then add 2.5 parts by weight of hydrogen peroxide and 15 parts by weight of acrylic acid thereto, stir evenly, then add 14 parts by weight of vitamin C aqueous solution and 2.5 parts by weight of 3-mercaptopropionic acid. After the addition is completed, react at a constant temperature of 30 °C for 2 h. After the reaction is completed, adjust the pH to 5-6 with 30% sodium hydroxide solution, cool to room temperature to obtain the water reducing agent mother liquor; the preparation process of the vitamin C aqueous solution is: dissolve vitamin C in deionized water and stir until dissolved, then obtain it; the dosage of vitamin C in deionized water is 0.008 g / mL.

[0053] The phosphoric acid functional monomer refers to the preparation of the phosphoric acid functional monomer in Example 1.

[0054] Comparative Example 5

[0055] Compared with Example 1, in the preparation process of the water reducing agent mother liquor in this comparative example, no phosphoric acid functional monomer and amide functional monomer are added, and the rest refers to Example 1.

[0056] The preparation process of the water-reducing agent mother liquor is as follows: Add 120 parts by weight of methyl allyl polyoxyethylene ether and 110 parts by weight of deionized water into a reactor, stir at 30 °C until completely dissolved, then stop heating. Then add 1.2 parts by weight of hydrogen peroxide and 40 parts by weight of acrylic acid thereto, stir evenly, then add 8 parts by weight of vitamin C aqueous solution and 1.2 parts by weight of 3-mercaptopropionic acid. After the addition is completed, react at a constant temperature of 30 °C for 2 h. After the reaction is completed, adjust the pH to 5 - 6 with 30% sodium hydroxide solution, and cool to room temperature to obtain the water-reducing agent mother liquor; the preparation process of the vitamin C aqueous solution is: dissolve vitamin C in deionized water and stir until dissolved, that is, obtain it; the dosage of vitamin C in deionized water is 0.008 g / mL.

[0057] Related tests:

[0058] Apply the water-reducing agent mother liquors prepared in Examples 1 to 3 and Comparative Examples 1 to 5 to concrete at a dosage of 0.16% of the total weight of the gelling material, and conduct performance tests on the concrete. The specific method refers to the test of GB8076-2008 "Concrete Admixtures". The slump test results are shown in Table 1, and the compressive strength results are shown in Table 2.

[0059] Table 1 Slump test results

[0060]

[0061] Table 2 Compressive strength test results

[0062]

[0063] It can be seen from the test results in Table 1 and Table 2 that the relevant properties of the water reducer mother liquor prepared in Examples 1 to 3 are better than those in Comparative Examples 1 to 5; by comparing Example 1 with Comparative Example 1 (replacing phytic acid with aminotrimethylphosphonic acid) and Comparative Example 3 (without adding phosphoric acid-based functional monomers), it can be known that after introducing a phosphoric acid group into the water reducer molecular chain, its slump and compressive strength are both improved to a certain extent. This is because the adsorption ability of the phosphoric acid group is stronger than that of the carboxylic acid group, and as an anchoring group, it can enhance the binding ability with calcium ions, making it easier for the prepared water reducer molecules to adsorb onto the surface of cement particles; at the same time, due to the large steric hindrance of the six-membered ring contained in phytic acid, its dispersion performance can be further improved. By comparing Example 1 with Comparative Example 2 (replacing ethyl 6-aminohexanoate with n-hexylamine) and Comparative Example 4 (without adding amide-based functional monomers), it can be known that functional groups such as amide groups and ester groups introduced into the water reducer molecular chain will slowly hydrolyze into anionic anchoring groups such as carboxyl groups in an alkaline environment, thereby promoting the secondary adsorption of the water reducer to cement particles and making it have a long slump retention performance. By comparing Example 1 with Comparative Example 3 (without adding phosphoric acid-based functional monomers), Comparative Example 4 (without adding amide-based functional monomers) and Comparative Example 5 (without adding phosphoric acid-based functional monomers and amide-based functional monomers), it can be known that after modification with phosphoric acid-based functional monomers and amide-based functional monomers, there is a synergistic effect between nitrogen and phosphorus contained in the water reducer molecular chain, assisting in forming a continuous hydrogen bond network between phosphoric acid molecules, generating steric hindrance, and further promoting the dispersion between cement particles.

[0064] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0065] Although the embodiments of the present application have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present application. The scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A process for preparing a non-collapse super-slow-release water-reducing agent mother solution, characterized in that: The steps include: S100, using raw materials including phytic acid and glycidyl methacrylate to obtain a phosphoric acid functional monomer through an epoxy ring-opening reaction; S200, using raw materials including 6-aminocaproic acid ethyl ester and acrylic acid to obtain amide functional monomers through acylation reaction; The super slow-release water reducing agent mother solution is obtained by copolymerizing S300, phosphoric acid functional monomers, amide functional monomers, polyether monomers and unsaturated carboxylic acids.

2. The process for preparing the non-collapse super-slow-release water-reducing agent mother solution according to claim 1, characterized in that: S100 specifically comprises: mixing phytic acid and dimethyl sulfoxide and reacting them at 45-60° C. for 25-45 minutes, then adding a mixed solution of glycidyl methacrylate and dimethyl sulfoxide, and reacting them at a constant temperature for 45-55 hours after the addition is completed, to obtain a phosphoric acid functional monomer.

3. The process for preparing the non-collapse super-slow-release water-reducing agent mother solution according to claim 2, characterized in that: The preparation process of the mixed solution is: adding glycidyl methacrylate to dimethyl sulfoxide and stirring evenly to obtain the mixed solution; the mass ratio of glycidyl methacrylate to dimethyl sulfoxide is 1-2:

10.

4. The process for preparing the non-collapse super-slow-release water-reducing agent mother solution according to claim 1, characterized in that: S200 specifically includes: in an inert atmosphere, uniformly mixing 6-aminocaproic acid ethyl ester, acrylic acid and a polymerization inhibitor, raising the temperature to 65-85° C. and reacting for 2-4 hours to obtain an amide functional monomer.

5. The process for preparing the non-collapse super-slow-release water-reducing agent mother solution according to claim 4, characterized in that: The mass ratio of 6-aminocaproic acid ethyl ester, acrylic acid and polymerization inhibitor is 1:1.8-2.8:0.03-0.

06.

6. The process for preparing the non-collapse super-slow-release water-reducing agent mother solution according to claim 1, characterized in that: S300 specifically includes: adding methyl allyl polyoxyethylene ether and deionized water into a reactor, stirring at 25-30° C. until completely dissolved, then adding phosphoric acid functional monomer and amide functional monomer thereto, stopping heating after mixing evenly, then adding hydrogen peroxide and acrylic acid thereto, stirring evenly, adding vitamin C aqueous solution and 3-mercaptopropionic acid thereto, reacting at a constant temperature for 1.5-3h after the reaction is completed, adjusting the pH to 5-6 after the reaction is completed, and cooling to room temperature to obtain the ultra-slow-release water-reducing agent mother liquor.

7. The process for preparing the non-collapse super-slow-release water-reducing agent mother solution according to claim 6, characterized in that: In step S300, the preparation process of the vitamin C aqueous solution is: dissolving vitamin C in deionized water and stirring until dissolved; the amount of vitamin C in the deionized water is 0.006-0.01 g / mL.

8. A super slow-release water reducing agent mother solution without collapse loss, characterized in that: The super slow-release water-reducing agent mother solution is obtained by using the preparation process of the super slow-release water-reducing agent mother solution without collapse loss as described in any one of claims 1 to 7.

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