A stable lithium silicate curing agent composition containing a complexing agent and its preparation method

Abstract

This invention discloses a stable lithium silicate curing agent composition containing a complexing agent and its preparation method. The composition includes lithium silicate as the main agent, deionized water, surfactant, disodium EDTA complexing agent, and organosilicon defoamer. The overall solid content is 12-15%, and the overall pH is 10.5-11.5. The preparation method involves dissolving the complexing agent, adding the lithium silicate as the main agent, and then adding the surfactant and defoamer. This invention solves the problems of easy precipitation and stratification, and difficulty in balancing permeability and wear resistance in existing products by forming a metal ion complex stable system with the complexing agent and lithium silicate, and by synergistically controlling the solid content and pH range.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a stable lithium silicate curing agent composition containing a complexing agent and its preparation method. Background Technology

[0002] Existing technologies include various lithium silicate curing agent formulations. These curing agents can penetrate into the concrete interior and react with calcium hydroxide to form insoluble calcium silicate crystals, thereby sealing pores, improving surface density and wear resistance. Some products also add a small amount of stabilizer to extend shelf life. However, existing formulations still have room for improvement in terms of long-term storage, construction adaptability, and overall performance.

[0003] Lithium silicate solutions have a high pH value (11-12), making them susceptible to the effects of carbon dioxide or metal ions in the environment during storage or transportation. This can lead to gelation, precipitation, or stratification, resulting in product failure or performance degradation. Furthermore, improper formulation of commonly used surfactants and defoamers can reduce the system's penetration rate and even generate residual foam, affecting the surface smoothness and abrasion resistance of the cured flooring. Additionally, many existing products do not precisely control the overall solid content and pH. Excessive solid content can lead to insufficient surface film formation and penetration depth, while insufficient solid content results in limited strength improvement. Large pH fluctuations can cause efflorescence or corrosion problems.

[0004] Therefore, in response to the problems mentioned above, the present invention provides a stable lithium silicate curing agent composition containing a complexing agent and its preparation method. Summary of the Invention

[0005] To overcome the problems of poor storage stability, easy precipitation and stratification, difficulty in balancing permeability and abrasion resistance, and unreasonable control of solid content and pH in existing lithium silicate curing agents, this invention proposes a stable lithium silicate curing agent composition containing a complexing agent and its preparation method. By introducing a specific proportion of a complexing agent (disodium EDTA) and lithium silicate as the main agent to form a metal ion complexing stable system, combined with selected deionized water, surfactants and organosilicon defoamers, and by precisely controlling the overall solid content and pH range of the composition, the invention extends storage stability while ensuring rapid penetration, low VOC, high abrasion resistance and no efflorescence.

[0006] The technical solution of the present invention is: a stable lithium silicate curing agent composition containing a complexing agent and its preparation method, comprising the following raw materials in the indicated mass percentages: 30-50% lithium silicate main agent, 40-60% deionized water, 0.5-2% surfactant, 0.1-1% complexing agent, and 0.05-0.5% organosilicon defoamer; The lithium silicate main agent has a solid content of 20-30% and a pH of 11-12; the deionized water has a conductivity ≤10μS / cm and a pH of 6-7; the surfactant is a nonionic surfactant with a solid content of 30-50% and a pH of 6-8; the complexing agent is disodium EDTA with a purity ≥99.5% and a pH of 7-9; and the organosilicon defoamer has a solid content of 20-30% and a pH of 6-8. The composition has an overall solid content of 12-15% and an overall pH of 10.5-11.5. The complexing agent and the lithium silicate main agent form a metal ion complexing and stabilizing system to inhibit precipitation and prolong storage stability. The mass ratio of the complexing agent to the lithium silicate main agent is 1:50-1:100, and the mass ratio of the surfactant to deionized water is 1:50-1:100.

[0007] This invention provides a method for preparing a stable lithium silicate curing agent composition containing a complexing agent, comprising the following steps: S1, Weigh out deionized water according to the ratio, add complexing agent, and stir at 300-600 rpm until completely dissolved (20-30℃) to obtain complexed solution; S2, under stirring conditions, slowly add lithium silicate main agent to the complexation solution, and continue stirring at a speed of 200-400 rpm for 10-20 minutes to form a mixture; S3, add surfactant to the mixture, add silicone defoamer after 1-3 minutes, and continue stirring for 5-10 minutes until the liquid is uniform, without foam and without stratification; S4, after standing and defoaming, filter and discharge to obtain a stable lithium silicate curing agent composition.

[0008] The beneficial effects of this invention are: 1. This invention, by adding 0.1-1% of disodium EDTA complexing agent, forms a metal ion complexing and stabilizing system with lithium silicate as the main agent. Combined with deionized water with a conductivity ≤10μS / cm, it effectively inhibits gelation and precipitation induced by trace metal ions. The stability period at room temperature exceeds 360 days, and the overall solid content change rate is less than 0.5%, avoiding the defect of existing products that fail due to precipitation and stratification.

[0009] 2. This invention precisely controls the overall solid content to 12-15%, while using surfactants to significantly reduce surface tension and using complexing agents to delay premature precipitation of lithium silicate, so that the penetration depth reaches more than 4.2 mm and the grinding pit length is as low as 0.16 mm. It simultaneously satisfies high penetration and high wear resistance, and solves the problem of mutual restriction between penetration depth and surface hardness in the prior art.

[0010] 3. This invention uses high-purity deionized water and controls the overall pH at 10.5-11.5. Combined with the chelating effect of complexing agents on free metal ions, it completely avoids the migration of alkaline substances to the surface. No white frost appears after 28 days of curing, and VOCs are not detected. This invention overcomes the problems of traditional curing agents being prone to alkali blooming and lacking environmental friendliness. Attached Figure Description

[0011] Figure 1 The diagram shown illustrates the preparation process of this invention. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] Please see Figure 1 The present invention provides Embodiment 1: Weigh the following raw materials according to the following mass percentages: 50% lithium silicate main agent (25% solid content, pH 11.5), 44.5% deionized water (4.5 μS / cm conductivity, pH 6.8), 1.5% surfactant (40% solid content, pH 7.2), 0.8% disodium EDTA powder complexing agent (99.5% purity, pH 8.0), and 0.2% silicone defoamer (25% solid content, pH 7.0).

[0014] Preparation method: S1, at 25°C, add deionized water to a mixing container, add complexing agent at a stirring speed of 450 rpm, and stir for about 8 minutes until completely dissolved; S2, then reduce the stirring speed to 300 rpm, slowly add the lithium silicate agent, and continue stirring for 15 minutes; S3, then add surfactant, add defoamer after 2 minutes, and continue stirring for 8 minutes; S4, let stand for 15 minutes to defoam, then filter through a 200-mesh filter before discharging.

[0015] The resulting composition was tested and found to have an overall solid content of 14.2%, an overall pH of 11.0, and an appearance of a transparent and homogeneous liquid with no precipitation or stratification.

[0016] This invention provides Embodiment 2: Weigh the following raw materials according to the following mass percentages: 30% lithium silicate main agent (25% solid content, pH 11.5), 60% deionized water (4.5 μS / cm conductivity, pH 6.8), 2% surfactant (40% solid content, pH 7.2), 1% complexing agent disodium EDTA powder (99.5% purity, pH 8.0), and 0.5% organosilicon defoamer (25% solid content, pH 7.0).

[0017] Preparation method: S1, at 25°C, add deionized water to a mixing container, add complexing agent at a stirring speed of 450 rpm, and stir for about 8 minutes until completely dissolved; S2, then reduce the stirring speed to 300 rpm, slowly add the lithium silicate agent, and continue stirring for 15 minutes; S3, then add surfactant, add defoamer after 2 minutes, and continue stirring for 8 minutes; S4, let stand for 15 minutes to defoam, then filter through a 200-mesh filter before discharging.

[0018] The resulting composition was tested and found to have an overall solid content of 12.3%, an overall pH of 10.7, and an appearance of a transparent and homogeneous liquid with no precipitation or stratification.

[0019] This invention provides embodiment 3: Weigh the following raw materials according to the following mass percentages: 45% lithium silicate main agent (25% solid content, pH 11.5), 49.5% deionized water (4.5 μS / cm conductivity, pH 6.8), 0.5% surfactant (40% solid content, pH 7.2), 1% disodium EDTA powder complexing agent (99.5% purity, pH 8.0), and 0.1% silicone defoamer (25% solid content, pH 7.0).

[0020] Preparation method: S1, at 25°C, add deionized water to a mixing container, add complexing agent at a stirring speed of 450 rpm, and stir for about 8 minutes until completely dissolved; S2, then reduce the stirring speed to 300 rpm, slowly add the lithium silicate agent, and continue stirring for 15 minutes; S3, then add surfactant, add defoamer after 2 minutes, and continue stirring for 8 minutes; S4, let stand for 15 minutes to defoam, then filter through a 200-mesh filter before discharging.

[0021] The resulting composition was tested and found to have an overall solid content of 13.8%, an overall pH of 11.2, and an appearance of a transparent and homogeneous liquid with no precipitation or stratification.

[0022] Comparative Example 1 provided by the present invention: In this example, the main component is lithium silicate (50%), deionized water (45.3%), surfactant (1.5%), and defoamer (0.2%), with no complexing agent added. The complexing agent dissolution step S1 is omitted during preparation; the remaining components are directly mixed. The resulting composition is initially transparent, but a slight milky white precipitate appears after standing for 24 hours.

[0023] Comparative Example 2 is provided in this invention: In this example, the main component is lithium silicate (50%), deionized water (43%), surfactant (1.5%), complexing agent (2%), and defoamer (0.5%). This exceeds the 0.1-1% range for complexing agent specified in this invention. The preparation method is the same as in Example 1. The resulting composition has an overall solid content of 15.3%, a pH of 10.3, and while clear in appearance, its viscosity is significantly increased, resulting in a decreased penetration rate during coating.

[0024] Comparative Example 3 is provided in this invention: In this example, tap water with a conductivity of 25 μS / cm was used instead of deionized water, and the rest was the same as in Example 1. Slight flocculent matter appeared during the preparation process, and precipitation became obvious after 24 hours.

[0025] This invention provides Comparative Example 4: In this example, the main component is 50% lithium silicate, 45.5% deionized water, 0.8% complexing agent, and 0.2% defoamer, with no surfactant added. By omitting the surfactant addition step in the preparation method, the resulting composition exhibits high surface tension, forms droplets on the concrete surface, and penetrates extremely slowly.

[0026] This invention provides Comparative Example 5: In this example, the main component is lithium silicate (50%), deionized water (44.7%), surfactant (1.5%), complexing agent (0.8%), and no defoamer is added. A large amount of foam is generated during the preparation process, and the foam cannot be completely eliminated after standing. Pinhole-like defects appear on the surface after curing.

[0027] This example tests the above embodiments and comparative examples, and the results are shown in Table 1: Table 1. Comparison of overall performance between embodiments of the present invention and comparative examples. Example 1 14.2 11.0 26.5 4.2 0.17 0.12 >360 none Not detected 233 5.8 Example 2 12.4 10.7 28.1 3.5 0.19 0.14 >300 none Not detected 208 5.2 Example 3 13.7 11.2 27.3 3.9 0.16 0.11 >330 none Not detected 225 5.6 Comparative Example 1 13.9 11.0 27.0 2.1 0.24 0.22 15 medium Not detected 158 4.5 Comparative Example 2 15.3 10.3 27.5 2.8 0.22 0.20 90 (Gel) slight Not detected 179 4.9 Comparative Example 3 13.8 10.8 27.2 1.9 0.26 0.25 3 serious Not detected 136 4.0 Comparative Example 4 13.5 10.9 68.0 1.5 0.31 0.30 >360 none Not detected 142 4.2 Comparative Example 5 14.0 11.0 26.8 3.8 0.23 0.19 >300 Minor pinholes Not detected 195 5.4 Table 1 summarizes the measured data of three embodiments of the present invention and five comparative examples on eleven key indicators, including solid content, pH value, surface tension, penetration depth, abrasion resistance, room temperature storage stability, efflorescence rating, VOC content, anti-permeability pressure ratio, and surface Mohs hardness. Through horizontal and vertical comparisons of these data, it is clear that the raw material ratio, overall solid content range (12-15%), overall pH range (10.5-11.5), and the synergistic effect of components such as complexing agents and surfactants, as defined in this invention, bring about comprehensive technical effects. Specifically: (1) The measured solid contents of Examples 1, 2, and 3 were 14.2%, 12.4%, and 13.7%, respectively, all falling within the preferred range of 12-15%, which is highly consistent with the theoretical calculation value, indicating that the preparation method of the present invention has good reproducibility and accurate proportioning. The pH values ​​of the three examples were 11.0, 10.7, and 11.2, respectively, which are also within the range of 10.5-11.5. In contrast, Comparative Example 2 had a solid content of 15.3%, exceeding the upper limit of 15%, which was due to the addition of a complexing agent (2%) exceeding the 1% limit of the present invention. Although Comparative Example 1 had a solid content of 13.9%, which was within the range, it lacked a complexing agent, resulting in a serious decline in other properties. Comparative Example 3 used a water source with excessive conductivity, and although the solid content was 13.8%, serious precipitation still occurred. These comparisons show that meeting the standards for solid content and pH value alone is not enough to obtain excellent comprehensive performance; multiple conditions, such as the type and amount of complexing agent and the quality of deionized water, must be met simultaneously.

[0028] (2) Surface tension is directly related to the wetting and penetration ability of the curing agent on the concrete surface. The surface tensions of Examples 1, 2, and 3 are 26.5 mN / m, 28.1 mN / m, and 27.3 mN / m, respectively, which are significantly lower than those of pure water (72 mN / m) and the formulation without added surfactant. Comparative Example 4, which has no added surfactant, has a surface tension as high as 68.0 mN / m, resulting in a penetration depth of only 1.5 mm, and a significant decrease in wear resistance and hardness. Comparative Examples 1, 2, 3, and 5, which all contain a specified amount of surfactant, also maintain a surface tension of around 27 mN / m, indicating that the surfactant itself can effectively reduce surface tension. However, if there is a lack of complexing agent or the water quality is impure, even with a low surface tension, the ideal penetration and stabilization effect cannot be achieved.

[0029] (3) Penetration depth is the core indicator for measuring whether liquid hardener can penetrate deep into the concrete and achieve overall reinforcement. The penetration depth of Example 1 reached 4.2 mm, Example 3 was 3.9 mm, and Example 2 was 3.5 mm, all of which are much higher than the comparative examples. The surface tension of Comparative Example 1 is similar to that of Example 1, but its penetration depth is only 2.1 mm, less than half of that of Example 1. This shows that simply reducing the surface tension is not enough to ensure deep penetration, because lithium silicate is prone to premature precipitation and blockage of pores when it comes into contact with calcium ions in the concrete pore solution. The EDTA disodium complexing agent added in this invention can temporarily chelate calcium, magnesium and other polyvalent metal ions in the solution, delaying the precipitation reaction of lithium silicate, allowing it to carry the effective components deeper and then slowly release and react, thereby greatly improving the penetration depth. In Comparative Example 2, the complexing agent was excessive (2%), which led to increased viscosity and a penetration depth of 2.8 mm; in Comparative Example 3, the water contained impurities, which also caused pore blockage, and the penetration depth was only 1.9 mm; in Comparative Example 4, there was no surfactant, and the penetration depth was the lowest at only 1.5 mm.

[0030] (4) Abrasion resistance is a key indicator of the final performance of the curing agent. According to the JC / T2158-2021 standard, the length of the grinding pit should be ≤0.20mm. The grinding pit lengths of Examples 1, 2, and 3 were 0.17mm, 0.19mm, and 0.16mm, respectively, all of which were qualified and had sufficient margin; among them, Example 3 reached the optimal level of 0.16mm. Comparative Example 1 (0.24mm), Comparative Example 2 (0.22mm), Comparative Example 3 (0.26mm), and Comparative Example 4 (0.31mm) were all unqualified, as was Comparative Example 5 (0.23mm). The trend of abrasion resistance loss was highly consistent with the length of the grinding pit: Example 1 lost only 0.12g, while Comparative Example 4 lost as much as 0.30g. Thus, it can be concluded that abrasion resistance is closely related to the penetration depth and the uniformity and density of the cured product. Due to the deep penetration and uniform reaction of this invention, the calcium silicate crystals generated form a continuous reinforcing layer below the concrete surface, thereby greatly improving the abrasion resistance. Although Comparative Example 1 has low surface tension, its penetration is shallow, forming only a thin layer on the surface, which easily exposes the underlying material after wear. Comparative Example 4, on the other hand, has an unwetted curing agent that accumulates on the surface, forming a loose layer after curing, resulting in extremely poor wear resistance. The technical solution of this invention achieves a balance between deep penetration and good wear resistance.

[0031] (5) The stability period of Example 1 exceeded 360 days, and that of Examples 2 and 3 exceeded 300 days and 330 days, respectively. Comparative Example 1 showed precipitation after only 15 days because of the lack of a complexing agent and the induction of lithium silicate colloid aggregation by trace metal ions. Comparative Example 2 was initially stable but gelled after 90 days due to the excessive amount of complexing agent. Comparative Example 3 showed severe precipitation after only 3 days due to the use of water with high conductivity. Although Comparative Examples 4 and 5 had poor other properties due to the lack of surfactants or defoamers, their storage stability was relatively long. This is because the system is closer to a pure lithium silicate solution when no surfactant is added, and the tendency to precipitate is lower. However, this is at the cost of sacrificing performance.

[0032] (6) Efflorescence (white bloom) is a common quality defect in concrete curing agents, which not only affects aesthetics but may also lead to bonding failure. Examples 1, 2, and 3 showed no white bloom during the 28-day curing period. Comparative Example 1 showed moderate efflorescence, Comparative Example 2 showed slight efflorescence, Comparative Example 3 showed severe efflorescence, Comparative Example 4 showed no efflorescence (because the curing agent did not penetrate effectively, and no actual reaction occurred), and Comparative Example 5 showed slight pinholes but no clear efflorescence. The main cause of efflorescence is the migration of alkaline substances (such as sodium hydroxide and calcium hydroxide) to the surface with moisture and their reaction with carbon dioxide to form carbonates. This invention uses high-purity deionized water (conductivity ≤10μS / cm), controls the overall pH at 10.5-11.5 (not too high), and stabilizes metal ions with a complexing agent, minimizing the release of free sodium and calcium ions. Furthermore, deep penetration and uniform reaction also prevent the local accumulation of alkaline substances. Comparative Example 3 suffered from severe efflorescence due to the presence of large amounts of calcium and magnesium ions in the water; Comparative Example 1, lacking a complexing agent, experienced efflorescence due to the decomposition of lithium silicate or the generation of free alkali through side reactions.

[0033] (7) The VOC content in all examples and comparative examples was undetectable and far below the national standard limit of 20 g / L. This is because the raw materials used in this invention are all water-based and solvent-free systems, and lithium silicate, deionized water, surfactants, disodium EDTA, and silicone defoamers do not contain volatile organic solvents. This shows that this invention has a universal advantage in environmental protection and does not affect the trade-off with other performance characteristics.

[0034] (8) The permeability pressure ratio reflects the degree to which the curing agent improves the permeability resistance of concrete. The permeability pressure ratio of Example 1 is as high as 233%, Example 3 is 225%, and Example 2 is 208%. Comparative Example 1 is only 158%, Comparative Example 4 is 142%, and Comparative Example 5 is 195%. The principle of improving permeability is that after lithium silicate penetrates, it reacts with calcium hydroxide to form water-insoluble calcium silicate gel, which blocks capillary pores and microcracks. At the same time, the complexing agent guides the reaction to proceed evenly, avoiding excessive local blockage that would leave seepage channels in non-permeable areas. The 233% of Example 1 is significantly better than that of the comparative example, which once again verifies the synergistic effect. Although Comparative Example 5 also added surfactants and complexing agents, due to the lack of defoamers, residual bubbles destroyed the continuity of the sealing layer, and the permeability pressure ratio dropped to 195%.

[0035] (9) The Mohs hardness of the blank concrete is approximately 3.5. Example 1 achieved 5.8 after treatment, Example 3 5.6, and Example 2 5.2, all showing an increase of more than two hardnesses. Comparative Example 1 only increased to 4.5, and Comparative Example 4 only to 4.2. The increase in hardness depends on the penetration depth and the number of calcium silicate crystals generated. The deep penetration of this invention allows more pores to be filled with high-hardness crystals, enhancing the overall hardness within a certain thickness below the surface, rather than just creating a thin shell. In Comparative Example 4, due to insufficient penetration, the curing agent mainly remained on the surface, forming an easily peelable hard shell after curing. Although the measured hardness was slightly improved, the wear resistance was extremely poor; this pseudo-hardness has no practical value.

[0036] (10) Considering all the data in Table 1, only Examples 1, 2, and 3 can simultaneously meet the following requirements: pit length ≤ 0.20 mm, penetration depth ≥ 3.5 mm, stabilization period ≥ 300 days, no efflorescence, no VOC detected, anti-permeability pressure ratio ≥ 200%, and Mohs hardness ≥ 5.2. All comparative examples failed to meet at least one of the key indicators.

[0037] In this example, compositions with complexing agent contents of 0%, 0.1%, 0.5%, 1%, and 2% were prepared, with the remaining components the same as in Example 1. The compositions were stored at room temperature (25°C) and high temperature (50°C), and the time to precipitation was recorded. The results are shown in Table 2 below: Table 2. Effect of different complexing agent contents on storage stability 0 15 7 +3.2 -0.9 0 0.1 120 35 +0.8 -0.3 0.1 0.5 360 and above (still stable) Above 90 (still stable) +0.2 -0.1 0.5 1.0 360 and above (still stable) Above 90 (still stable) +0.2 -0.1 1.0 2.0 90 (gelation) 30 (gelation) +5.1 -0.7 2.0 As shown in Table 2, the storage stability is significantly improved when the complexing agent content is in the range of 0.1% to 1%. When the content is 0%, precipitation occurs after 15 days, which is due to the aggregation caused by free metal ions in the lithium silicate solution. When the content exceeds 1%, the excess disodium EDTA will competitively complex with lithium silicate, which will disrupt the colloidal balance of lithium silicate and lead to gelation.

[0038] In this example, the proportions of other components were kept constant (same as in Example 1), and the overall solid content was adjusted to 10%, 12%, 14%, 16%, and 18% by changing the amount of deionized water. Penetration depth and abrasion resistance (groove length) were tested. The results are shown in Table 3. Table 3. Impact of Total Solid Content on Key Performance Indicators 10 4.5 0.24 4.8 slight 12 4.3 0.20 5.2 none 14 4.2 0.17 5.8 none 16 3.0 0.19 5.9 slight 18 2.1 0.21 6.0 medium As shown in Table 3, when the solid content is below 12%, the wear resistance is substandard (wear pits > 0.20 mm); when the solid content is above 15%, the penetration depth decreases sharply, and the risk of efflorescence increases. Only by controlling the overall solid content at 12-15% can good permeability (≥3.5 mm) and wear resistance (≤0.20 mm) be obtained simultaneously.

[0039] In this example, the pH value of the composition of Example 1 was adjusted to 9.5, 10.5, 11.0, 11.5, and 12.0 using dilute hydrochloric acid or dilute lithium hydroxide. Then, the initial viscosity, the viscosity change rate after 30 days of storage at room temperature, and the 28-day surface hardness increase of the concrete specimens were tested. The results are shown in Table 4. Table 4. Effect of pH value on stability and reactivity 9.5 8.2 +45 (gelation) 4.5 7 (Serious) 10.5 6.5 +5 5.4 None (28 days alkali-free) 11.0 6.8 +2 5.8 none 11.5 7.1 +8 5.7 none 12.0 8.5 +25 (precipitate) 5.1 14 (Mild) As shown in Table 4, when the pH is in the range of 10.5-11.5, the viscosity is stable, the hardness is significantly improved, and there is no efflorescence. When the pH is below 10.5, lithium silicate is unstable and easily gels; when the pH is above 11.5, the excessive alkalinity accelerates the surface carbonization reaction, resulting in efflorescence and a decrease in hardness.

[0040] This example designs four formulations: 1 (no complexing agent, no surfactant), 2 (with complexing agent, no surfactant), 3 (no complexing agent, with surfactant), and 4 (Example 1 of this invention). Surface tension, penetration depth, abrasion resistance, and storage stability were tested. The results are shown in Table 5. Table 5 Synergistic effects of complexing agents, surfactants, and defoamers 1 68.5 0.8 0.45 10 (precipitate) 2 67.2 1.2 0.39 360 (Stable) 3 26.8 3.5 0.23 20 (precipitate) 4 26.5 4.2 0.17 >360 As shown in Table 5, although the complexing agent alone can significantly improve stability, it has poor permeability and wear resistance; the surfactant alone has good permeability but poor stability; only when both are used at the same time can the excellent effect of stability period of more than one year, penetration depth of more than 4 mm and wear resistance meeting the standard be achieved. This shows that there is a significant synergistic effect between the complexing agent and the surfactant, rather than a simple additive effect.

[0041] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments that can be applied to other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A stable lithium silicate curing agent composition containing a complexing agent, characterized in that, The composition comprises the following raw materials in weight percentages: 30-50% lithium silicate, 40-60% deionized water, 0.5-2% surfactant, 0.1-1% complexing agent, and 0.05-0.5% organosilicon defoamer.

2. The stable lithium silicate curing agent composition containing a complexing agent according to claim 1, characterized in that: The lithium silicate main agent has a solid content of 20-30% and a pH of 11-12.

3. The stable lithium silicate curing agent composition containing a complexing agent according to claim 1, characterized in that: The deionized water has a conductivity of ≤10μS / cm and a pH of 6-7.

4. The stable lithium silicate curing agent composition containing a complexing agent according to claim 1, characterized in that: The surfactant is a nonionic surfactant with a solid content of 30-50% and a pH of 6-8.

5. A stable lithium silicate curing agent composition containing a complexing agent according to claim 1, characterized in that: The complexing agent is disodium EDTA with a purity of ≥99.5% and a pH of 7-9.

6. The stable lithium silicate curing agent composition containing a complexing agent according to claim 1, characterized in that: The organosilicon defoamer has a solid content of 20-30% and a pH of 6-8.

7. The stable lithium silicate curing agent composition containing a complexing agent according to claim 1, characterized in that: The composition has an overall solid content of 12-15% and an overall pH of 10.5-11.

5. The complexing agent and the lithium silicate main agent form a metal ion complexing and stabilizing system, which is used to inhibit precipitation and prolong storage stability.

8. A stable lithium silicate curing agent composition containing a complexing agent according to claim 1, characterized in that: The mass ratio of the complexing agent to the lithium silicate main agent is 1:50-1:100, and the mass ratio of the surfactant to deionized water is 1:50-1:

100.

9. A method for preparing a stable lithium silicate curing agent composition containing a complexing agent, comprising preparing the stable lithium silicate curing agent composition containing a complexing agent as described in any one of claims 1-8, characterized in that, Includes the following steps: S1, Weigh out deionized water according to the ratio, add complexing agent, stir until completely dissolved to obtain complexed solution; S2, under stirring conditions, slowly add lithium silicate main agent to the complexation solution, and continue stirring for 10-20 minutes to form a mixture; S3, add surfactant and silicone defoamer to the mixture in sequence, and continue stirring for 5-10 minutes until the liquid is uniform, without foam and without separation; S4, after standing and defoaming, filter and discharge to obtain a stable lithium silicate curing agent composition.

10. The method for preparing a stable lithium silicate curing agent composition containing a complexing agent according to claim 9, characterized in that: In step S1, the stirring speed is 300-600 rpm and the dissolution temperature is 20-30℃; in step S2, the stirring speed is 200-400 rpm; and in step S3, the time interval between adding the surfactant and the defoamer is 1-3 minutes.

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