Polyether organic silicon foam control agent, cement-based material shrinkage performance control agent and preparation method of polyether organic silicon foam control agent

Abstract

The invention relates to the technical field of building admixtures, in particular to a polyether organic silicon foam control agent, a cement-based material shrinkage performance control agent and a preparation method of the polyether organic silicon foam control agent. The polyether organic silicon foam control agent has a specific structural formula and is prepared by reaction of hydrogen-containing silicone oil, methoxy polyethylene glycol, alkynol and the like. The cement-based material shrinkage performance control agent is formed by blending a shrinkage reducing type water reducing agent and a polyether organic silicon foam control agent, the shrinkage reducing type water reducing agent is formed by polymerizing a vinyl polyether macromonomer, unsaturated carboxylic acid and a functional monomer, and the functional monomer is generated by reacting tetraalkoxy silane with unsaturated polyether. The control agent can effectively control concrete shrinkage and solve the shrinkage cracking problem, concrete self-shrinkage and drying shrinkage are reduced by optimizing the bubble structure, reducing the surface tension of a pore solution and other modes, an effective way is provided for concrete performance regulation and control, and the control agent has important application value.

Description

Technical Field

[0001] The invention relates to the technical field of building admixtures, and in particular to a polyether organosilicon foam control agent, a cement-based material shrinkage performance control agent and a preparation method thereof. Background Art

[0002] As a basic material widely used in modern construction projects, the performance of concrete is directly related to the safety, durability and overall quality of the building structure. However, the shrinkage cracking of concrete has always been an extremely difficult problem in the engineering field, bringing many adverse effects to engineering construction.

[0003] A large amount of engineering practice and research data show that the causes of most cracks in concrete structures are closely related to different types of shrinkage deformation. Concrete shrinkage deformation mainly includes autogenous shrinkage, drying shrinkage, plastic shrinkage and temperature shrinkage. Among them, autogenous shrinkage is due to the consumption of internal water during cement hydration, which leads to a decrease in the relative humidity inside the concrete, resulting in volume shrinkage; drying shrinkage is the volume reduction caused by the loss of water in a dry environment; plastic shrinkage usually occurs in the early stage after concrete pouring, and the shrinkage caused by the rapid evaporation of surface water; temperature shrinkage is the phenomenon of thermal expansion and contraction of concrete when the temperature changes. The existence of these shrinkage cracks is not only a surface flaw, but also will lead to a series of serious consequences. In the long run, shrinkage cracks will continue to develop and expand, eventually leading to a decrease in the bearing capacity of the structure, greatly shortening the service life of the building, increasing the cost of maintenance and reinforcement, and may even cause safety accidents.

[0004] With the vigorous development of infrastructure construction in my country, many major projects are constantly advancing to special environmental areas such as plateaus, deserts, and oceans. These areas have harsh environmental conditions such as large temperature differences, extreme dryness, and strong corrosion, which put forward higher requirements on the performance of concrete. For example, in plateau areas, the temperature difference between day and night is large, and concrete is subjected to large temperature stress during repeated temperature changes, which is prone to temperature cracks; the climate in desert areas is dry, and the drying shrinkage problem of concrete is more prominent; the high salinity, high humidity and seawater erosion in the marine environment pose a serious threat to the durability of concrete. At the same time, the increasing scarcity of high-quality raw material resources has forced more use of alternative materials such as industrial waste slag in engineering. Although this has achieved the comprehensive utilization of resources to a certain extent, it has also made the composition of concrete more complicated. The composition, activity and particle characteristics of industrial waste slag are different from those of traditional raw materials, which further increases the risk of shrinkage cracking of concrete. In this context, how to effectively inhibit the shrinkage cracking of concrete has become a key issue to be solved in concrete engineering construction, and it is also one of the hot spots in the current research field. Summary of the invention

[0005] The present invention aims to overcome the problem of concrete shrinkage cracking, reduce concrete shrinkage, and meet the demand for crack resistance. A polyether organosilicon foam control agent is provided, and its structural formula is: ; Wherein, c, d, e, f, g, h are integers of 1 to 20; i is an integer of 10 to 30, R2, R3 are H or CH3 or CH2CH3 or phenyl, and R4 is H or phenyl.

[0006] On the basis of the above technical solution, further, the preparation method of the above polyether silicone foam control agent is to add hydrogen silicone oil, methoxy polyethylene glycol, and acetylene alcohol in a molar ratio of 1: (1.1-1.5): (0.1-0.5) to ethylene glycol and stir, and add a catalyst acid; Passing nitrogen into the reaction system environment, heating the reaction system to 60-100° C. to carry out a condensation reaction, and obtaining the polyether silicone foam control agent after the reaction is completed; The amount of the catalyst acid used is 0.1% to 0.5% of the mass of the hydrogen-containing silicone oil; On the basis of the above technical solution, further, the catalyst acid is zinc acetate; The molecular weight of the methoxy polyethylene glycol is 500-1000.

[0007] The present invention also provides a method for preparing a cement-based material shrinkage performance control agent, which is prepared by blending a shrinkage-reducing water reducer and a polyether organosilicon foam control agent, wherein the mass ratio of the shrinkage-reducing water reducer to the polyether organosilicon foam control agent is (80-100): (1-10); The shrinkage-reducing water-reducing agent is prepared by polymerization reaction of vinyl polyether macromonomer, unsaturated carboxylic acid and functional monomer in a mass ratio of (60-100): (10-20): (10-40) in the presence of water, initiator and chain transfer agent; The polyether organosilicon foam control agent is any of the polyether organosilicon foam control agents described above.

[0008] On the basis of the above technical solution, further, the functional monomer is generated by reacting tetraalkoxysilane with unsaturated polyether, and the structural formula of the functional monomer is as follows: ; Wherein R1 is a hydrocarbon group of 1 to 20 carbon atoms, a is an integer of 1 to 4, b is an integer of 5 to 30, and m is an integer of 0 to 3.

[0009] On the basis of the above technical solution, further, the preparation method of the functional monomer is: by weight, add 3 to 5 parts of tetraalkoxysilane, 30 to 60 parts of unsaturated polyether, 0.03 to 0.08 parts of p-toluenesulfonic acid or acetic acid, 1 to 5 parts of methanol and 0.3 to 0.9 parts of water to a container equipped with a thermometer and a vacuum distiller, heat to 50 to 65° C., react for 2 to 5 hours, continue to heat to 105 to 120° C., react for 2 to 5 hours, and remove methanol by reduced pressure distillation to obtain the functional monomer; Preferably, the molecular weight of the unsaturated polyether is 500-1000.

[0010] On the basis of the above technical solution, further, the initiator is a hydrogen peroxide-reducing agent system; The shrinkage-reducing water-reducing agent is prepared as follows: by weight, 10 to 40 parts of functional monomers, 60 to 100 parts of vinyl polyether macromonomers, 1 to 2 parts of hydrogen peroxide, and 50 to 100 parts of water are added to a reaction kettle, the temperature is controlled at 20 to 25° C., and then a reducing agent aqueous solution, an unsaturated carboxylic acid aqueous solution, and a chain transfer agent aqueous solution are respectively added dropwise for 3 to 4 hours. After the addition is completed, the temperature is kept for 1 to 2 hours, and water is added to adjust the concentration to obtain a reaction product of 50%; The pH of the reaction product is adjusted to 6.0-7.0 with sodium hydroxide to obtain a shrinkage-reducing water-reducing agent.

[0011] On the basis of the above technical solution, further, the molecular weight of the vinyl polyether macromonomer is 3000-6000; The reducing agent aqueous solution is prepared by dissolving 0.4-0.9 parts of reducing agent in 30 parts of water; the chain transfer agent aqueous solution is prepared by dissolving 0.3-1.0 parts of chain transfer agent in 30 parts of water; and the unsaturated carboxylic acid aqueous solution is prepared by dissolving 10-20 parts of acrylic acid in 30 parts of water.

[0012] On the basis of the above technical solution, further, the reducing agent is at least one of bisulfite, sulfite, bleaching agent, and vitamin C; The chain transfer agent is at least one of mercaptoethanol, thioglycolic acid, mercaptopropionic acid, n-dodecyl mercaptan or tert-dodecyl mercaptan.

[0013] The present invention also provides a cement-based material shrinkage performance controller prepared by any of the above methods for preparing the cement-based material shrinkage performance controller.

[0014] The technical solution of the present invention has the following principles and beneficial effects: The polyether organosilicon foam control agent provided by the present invention is used in the field of building materials, and can effectively improve and optimize the bubble structure of fresh concrete, thereby improving the pore structure of concrete, making the concrete more compact, and reducing concrete shrinkage. The shrinkage performance control agent for cement-based materials provided by the present invention creatively utilizes functional monomers to introduce the polyether compound of tetraalkoxysilane into a shrinkage-reducing water-reducing agent. It can reduce the surface tension of the concrete pore solution, thereby reducing the capillary negative pressure, and blocking the inducement chain of concrete autogenous shrinkage and drying shrinkage. The shrinkage performance control agent for cement-based materials also has an excellent ability to delay cement hydration, which not only effectively alleviates the downward trend of the relative humidity inside the concrete, but also significantly increases the supersaturation and crystallization pressure of calcium hydroxide and calcium aluminate by changing the ion concentration of the pore solution. This series of synergistic effects forms a compensating stress mechanism inside the concrete, curbs the occurrence of concrete shrinkage, and lays a solid foundation for preventing concrete cracking. The unique molecular structure of the polyether silicone foam control agent can improve the bubble structure of fresh concrete. During the pouring and hardening process of concrete, its bubble structure is like a fine skeleton, supporting and improving the pore structure of concrete, promoting a more reasonable distribution of pores inside the concrete, and significantly improving the compactness of concrete. This densification effect is directly converted into an effective inhibition of concrete shrinkage, forming a complementary synergistic effect with the shrinkage-reducing water-reducing agent.

[0015] The cement-based material shrinkage performance controller of the present invention can effectively control the shrinkage of concrete, solve the shrinkage cracking problem in concrete engineering, provide a convenient and economical way to regulate and improve the performance of concrete, and has important practical application value. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] The present invention provides the following polyether organosilicon foam control agent embodiment, and its structural formula is: ; Wherein, c, d, e, f, g, h are integers of 1 to 20; i is an integer of 10 to 30, R2, R3 are H or CH3 or CH2CH3 or phenyl, and R4 is H or phenyl.

[0018] The present invention also provides the following embodiments of the cement-based material shrinkage performance control agent: Example 1 Synthesis of functional monomer: Add 3g tetramethoxysilane, 30g methyl allyl polyethylene glycol ether (molecular weight 500), 0.03g p-toluenesulfonic acid, 1g methanol and 0.3g water into the flask in the vacuum distillation apparatus, react at 50℃ for 2h, heat to 105℃ and react for another 2h, and distill under reduced pressure to obtain the functional monomer.

[0019] Preparation of shrinkage-reducing water-reducing agent: 10g functional monomer, 80g ethylene glycol monovinyl polyglycol ether (molecular weight 3000), 1g hydrogen peroxide and 50g water are added to the reactor, the temperature is controlled at 20℃, and vitamin C aqueous solution (0.4g vitamin C dissolved in 30g water), acrylic acid aqueous solution (10g acrylic acid dissolved in 30g water) and thioglycolic acid aqueous solution (0.3g thioglycolic acid dissolved in 30g water) are added dropwise at a uniform speed. The addition takes 3h, and the mixture is kept warm for 1h. The amount of water is adjusted to obtain a 50% concentration product, and the pH is adjusted to 6.0-7.0.

[0020] Preparation of polyether silicone foam control agent: 0.1 mol hydrogenated silicone oil, 0.15 mol methoxy polyethylene glycol (molecular weight 1000), 0.05 mol 2-methyl-3-butyn-2-ol, 0.07 g zinc acetate and 30 ml ethylene glycol were added into a flask, stirred and nitrogen was passed through, reacted at 100°C for 5 h, and cooled to 60°C.

[0021] Preparation of the control agent: 100 g of the shrinkage-reducing water-reducing agent was mixed with 1 g of the polyether silicone foam control agent to obtain a cement-based material shrinkage performance control agent.

[0022] Example 2 Synthesis of functional monomer: Add 4g tetramethoxysilane, 40g isopentenyl polyethylene glycol ether (molecular weight 800), 0.04g acetic acid, 2g methanol and 0.4g water into the flask in the vacuum distillation apparatus, react at 55°C for 3h, heat to 110°C and react for another 3h, and distill under reduced pressure to obtain the functional monomer.

[0023] Preparation of shrinkage-reducing water-reducing agent: 20g functional monomer, 90g 4-hydroxybutyl vinyl polyethylene glycol ether (molecular weight 5000), 1.2g hydrogen peroxide and 60g water are added to the reactor. The temperature is controlled at 25℃. The aqueous solution of bleaching powder (0.7g bleaching powder dissolved in 30g water), acrylic acid aqueous solution (17g acrylic acid dissolved in 30g water) and mercaptopropionic acid aqueous solution (0.6g mercaptopropionic acid dissolved in 30g water) are added dropwise at a uniform speed. The addition takes 3h. The mixture is kept warm for 1h. The amount of water is adjusted to obtain a 50% concentration product and the pH is adjusted to 6.0-7.0.

[0024] Preparation of polyether silicone foam control agent: 0.1 mol hydrogen silicone oil, 0.11 mol methoxy polyethylene glycol (molecular weight 800), 0.01 mol 1,1,3-triphenyl-2-propynol, 0.48 g zinc acetate and 30 ml ethylene glycol were added into a flask, stirred with nitrogen, reacted at 80°C for 8 hours, and cooled to 40°C.

[0025] Preparation of the control agent: 90 g of the shrinkage-reducing water-reducing agent and 5 g of the polyether silicone foam control agent were blended to obtain a cement-based material shrinkage performance control agent.

[0026] Example 3 Synthesis of functional monomer: Add 5g tetramethoxysilane, 60g methyl allyl polyethylene glycol ether (molecular weight 1000), 0.08g p-toluenesulfonic acid, 5g methanol and 0.9g water into the flask in the vacuum distillation apparatus, react at 60℃ for 5h, heat to 120℃ and react for another 5h, and distill under reduced pressure to obtain the functional monomer.

[0027] Preparation of shrinkage-reducing water-reducing agent: 40g functional monomer, 100g ethylene glycol monovinyl polyglycol ether (molecular weight 6000), 2g hydrogen peroxide and 100g water are added to the reactor, the temperature is controlled at 20℃, and vitamin C aqueous solution (0.9g vitamin C dissolved in 30g water), acrylic acid aqueous solution (20g acrylic acid dissolved in 30g water) and thioglycolic acid aqueous solution (1.0g thioglycolic acid dissolved in 30g water) are added dropwise at a uniform speed. The addition takes 3h, and the mixture is kept warm for 1h. The amount of water is adjusted to obtain a 50% concentration product, and the pH is adjusted to 6.0-7.0.

[0028] Preparation of polyether silicone foam control agent: 0.1 mol hydrogen silicone oil, 0.13 mol methoxy polyethylene glycol (molecular weight 500), 0.03 mol 3-butyn-2-ol, 0.33 g zinc acetate and 30 ml ethylene glycol were added into a flask, stirred and nitrogen was passed through, reacted at 60°C for 10 h, and cooled to 40°C.

[0029] Preparation of control agent: 100 g of shrinkage-reducing water-reducing agent was mixed with 3 g of polyether silicone foam control agent to prepare a shrinkage control agent for cement-based materials.

[0030] Comparative Example 1 Compared with Example 1, no functional monomer was added in the preparation of the shrinkage-reducing water-reducing agent, and the remaining steps were the same as those in Example 1; Preparation of the control agent: 100 g of the shrinkage-reducing water-reducing agent prepared without adding the functional monomer is blended with 1 g of the polyether silicone foam control agent to obtain the control agent.

[0031] Comparative Example 2 The shrinkage-reducing water-reducing agent prepared in Example 1 was used as the controlling agent.

[0032] Comparative Example 3 (Ordinary water reducing agent) Kezhijie New Materials Group Co., Ltd. produces PS polycarboxylate water reducer.

[0033] The control agents prepared in the above examples and comparative examples were used to test the performance of concrete mixtures according to GB / T 50080-2016 "Standard for Test Methods for Performance of Ordinary Concrete Mixtures" and JC / T 2361-2016 "Mortar and Concrete Shrinkage Reducing Agents".

[0034] Concrete mix ratio: cement 360kg / m 3 、Mechanical sand 790kg / m 3 、Stone 1060kg / m 3 、Water 162kg / m 3 .

[0035] The performance test results are shown in the following table: Table 1 sample Dosage / % Initial slump / mm 7d reduction rate / % Example 1 0.15 200 35 Example 2 0.15 205 38 Example 3 0.15 210 36 Comparative Example 1 0.15 205 14 Comparative Example 2 0.15 200 23 Comparative Example 3 0.15 190 7 Through the above experimental tests and comparisons, we can know that: Compared with Comparative Example 1, the control agents prepared in Examples 1 to 3 can significantly reduce the shrinkage of concrete when applied to concrete. This is because in Examples 1 to 3, the polyether compound of tetraalkoxysilane is introduced into the shrinkage-reducing water-reducing agent by using functional monomers, and combined with the polyether organosilicon foam control agent and other technical features, the capillary negative pressure can be reduced by reducing the surface tension of the concrete pore solution, thereby reducing the autogenous shrinkage and drying shrinkage of the concrete, and the shrinkage of the concrete is reduced by delaying cement hydration and thereby relieving the decrease in internal relative humidity, changing the ion concentration of the pore solution and thereby increasing the supersaturation and crystallization pressure of calcium hydroxide and ettringite. Comparative Example 1 uses a water-reducing agent without functional monomers mixed with a polyether organosilicon foam control agent as an additive for concrete, and the shrinkage reduction performance of the concrete is much lower than that of the control agent obtained in Examples 1 to 3.

[0036] Compared with Comparative Example 2, the control agents prepared in Examples 1 to 3 can reduce the shrinkage of concrete when applied to concrete, mainly because the polyether organosilicon foam control agents prepared in Examples 1 to 3, combined with the shrinkage-reducing water reducer and other technical features, can effectively improve and optimize the bubble structure of fresh concrete, thereby improving the pore structure of concrete, making the concrete more compact and reducing the shrinkage of concrete. Comparative Example 2 does not add the polyether organosilicon foam control agent, and the shrinkage reduction performance of concrete is lower than that of the control agents obtained in Examples 1 to 3.

[0037] Comparative Example 3 is a common water reducing agent, and compared with the example, no functional monomer and polyether organosilicon foam control agent are added. Compared with Comparative Example 3, the control agents prepared in Examples 1 to 3 can significantly reduce the shrinkage of concrete when applied to concrete, mainly because the shrinkage reducing water reducing agent and the polyether organosilicon foam control agent in the admixtures of Examples 1 to 3 form a good synergistic effect, effectively reducing the shrinkage of concrete.

[0038] In the technical solution of the present invention, a shrinkage-reducing water-reducing agent is blended with a polyether silicone foam control agent to prepare a shrinkage control agent. The technical features cooperate with each other, which can effectively control the shrinkage of concrete and solve the problem of concrete shrinkage cracking.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A polyether silicone foam control agent, characterized in that: Its structural formula is: ； Wherein, c, d, e, f, g, h are integers of 1 to 20; i is an integer of 10 to 30, R2, R3 are H or CH3 or CH2CH3 or phenyl, and R4 is H or phenyl.

2. A method for preparing the polyether silicone foam control agent according to claim 1, characterized in that: Add hydrogen-containing silicone oil, methoxy polyethylene glycol, and acetylenic alcohol into ethylene glycol in a molar ratio of 1:(1.1-1.5):(0.1-0.5) and stir, and add catalyst acid; Nitrogen is passed through the reaction system environment, and the reaction system is heated to 60-100° C. to carry out a condensation reaction. After the reaction is completed, the polyether silicone foam control agent is obtained.

3. The method for preparing the polyether silicone foam control agent according to claim 2, characterized in that: The amount of the catalyst acid used is 0.1% to 0.5% of the mass of the hydrogen-containing silicone oil; The catalyst acid is zinc acetate; The molecular weight of the methoxy polyethylene glycol is 500-1000.

4. A method for preparing a cement-based material shrinkage performance control agent, characterized in that: It is blended by a shrinkage-reducing water-reducing agent and a polyether silicone foam control agent, wherein the weight ratio of the shrinkage-reducing water-reducing agent to the polyether silicone foam control agent is (80-100): (1-10); The shrinkage-reducing water-reducing agent is prepared by polymerization reaction of vinyl polyether macromonomer, unsaturated carboxylic acid and functional monomer in a mass ratio of (60-100): (10-20): (10-40) in the presence of water, initiator and chain transfer agent; The polyether organosilicon foam control agent is the polyether organosilicon foam control agent according to any one of claims 1 to 3; The functional monomer is produced by the reaction of tetraalkoxysilane and unsaturated polyether.

5. The method for preparing the cement-based material shrinkage performance controller according to claim 4, characterized in that: The structural formula of the functional monomer is as follows: ； Wherein, R1 is a hydrocarbon group of 1 to 20 carbon atoms, a is an integer of 1 to 4, b is an integer of 5 to 30, and m is an integer of 0 to 3.

6. The method for preparing the cement-based material shrinkage performance controller according to claim 5, characterized in that: The preparation method of the functional monomer is as follows: by weight, 3 to 5 parts of tetraalkoxysilane, 30 to 60 parts of unsaturated polyether, 0.03 to 0.08 parts of p-toluenesulfonic acid or acetic acid, 1 to 5 parts of methanol and 0.3 to 0.9 parts of water are added into a container, heated to 50 to 65° C., reacted for 2 to 5 hours, continued to heat to 105 to 120° C., reacted for 2 to 5 hours, and discharged the methanol by reduced pressure distillation to obtain the functional monomer; Preferably, the molecular weight of the unsaturated polyether is 500-1000.

7. The method for preparing the cement-based material shrinkage performance controller according to claim 4, characterized in that: The initiator is a hydrogen peroxide-reducing agent system; The shrinkage-reducing water-reducing agent is prepared as follows: by weight, 10 to 40 parts of functional monomers, 60 to 100 parts of vinyl polyether macromonomers, 1 to 2 parts of hydrogen peroxide, and 50 to 100 parts of water are added to a reaction kettle, the temperature is controlled at 20 to 25° C., and a reducing agent aqueous solution, an unsaturated carboxylic acid aqueous solution, and a chain transfer agent aqueous solution are added dropwise for 3 to 4 hours. After the addition is completed, the mixture is kept warm for 1 to 2 hours, and water is added to adjust the concentration to obtain a reaction product of 50%; The pH of the reaction product is adjusted to 6.0-7.0 with sodium hydroxide to obtain a shrinkage-reducing water-reducing agent.

8. The method for preparing the cement-based material shrinkage performance controller according to claim 7, characterized in that: The molecular weight of the vinyl polyether macromonomer is 3000 to 6000; The reducing agent aqueous solution is prepared by dissolving 0.4-0.9 parts of reducing agent in 30 parts of water; the chain transfer agent aqueous solution is prepared by dissolving 0.3-1.0 parts of chain transfer agent in 30 parts of water; and the unsaturated carboxylic acid aqueous solution is prepared by dissolving 10-20 parts of acrylic acid in 30 parts of water.

9. The method for preparing the cement-based material shrinkage performance controller according to claim 7, characterized in that: The reducing agent is at least one of bisulfite, sulfite, bleaching agent, and vitamin C; The chain transfer agent is at least one of mercaptoethanol, thioglycolic acid, mercaptopropionic acid, n-dodecyl mercaptan or tert-dodecyl mercaptan.

10. A cement-based material shrinkage performance controller prepared by the method for preparing a cement-based material shrinkage performance controller according to any one of claims 4 to 9.

Images