Preparation method and application of HEDP-PEG high-temperature-resistant slow-release retarder
The unique 3D mesh structure design of HEDP-PEG retarder solves the problem of uneven release of retarder at high temperatures, achieving a stable retarding effect in high-temperature environments. It is suitable for large-volume concrete construction and has broad application prospects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KZJ NEW MATERIALS GROUP CO LTD
- Filing Date
- 2024-12-13
- Publication Date
- 2026-06-12
AI Technical Summary
Existing retarders are prone to decomposition or chemical failure at high temperatures, resulting in uneven release and unstable control effects. They are difficult to achieve slow and stable release in high-temperature or large-volume concrete, affecting construction progress and quality.
The HEDP-PEG retarder is used, which forms a unique 3D network structure by cross-linking the PEG molecular structure with HEDP molecules. Combined with the temperature sensitivity of PEG, the retarder can be precisely controlled and released at high temperatures, thus enhancing stability and dispersion performance.
It achieves uniform distribution and stable release of retarder in high-temperature environments, significantly prolongs the initial setting time of mortar, ensures construction quality, reduces production costs, and is suitable for large-scale industrial production.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of building admixtures technology, and in particular to a method for preparing and applying a HEDP-PEG high-temperature resistant slow-release retarder. Background Technology
[0002] In the field of concrete construction, especially in large-volume and high-temperature environments, retarders are crucial for ensuring concrete performance and construction quality. Currently, commonly used retarders include carboxylates, organophosphonates, and polymer-modified materials, which primarily achieve their retarding effect by complexing calcium ions or inhibiting hydration reactions. However, existing retarders have several drawbacks.
[0003] Many retarders are prone to decomposition or chemical inactivation at high temperatures, leading to uneven release and unstable control effects. When reacting with calcium ions in cement, temperature changes exacerbate their decomposition, making the hydration reaction time unpredictable and affecting project progress and quality. Traditional retarders are difficult to control the release rate at high temperatures, easily resulting in problems such as early deactivation, insufficient or excessive retardation time.
[0004] These problems stem from the single mechanism of action of existing retarders, which delay the hydration reaction by directly complexing hydrated calcium ions or through surface adsorption. While they have a certain retarding effect at room temperature, in high-temperature or large-volume concrete applications, the hydration reaction accelerates, the retarder molecules quickly lose their activity, and they cannot achieve slow and stable release. This results in limited construction time, premature curing of concrete, and affects construction quality. Summary of the Invention
[0005] To address the problems mentioned above, this invention provides a HEDP-PEG high-temperature resistant slow-release retarder, with the following structural formula:
[0006] ;
[0007] PEG is polyethylene glycol, with a molecular weight of 2000–5000, and its structural formula is as follows:
[0008] n = 45~110;
[0009] HEDP is an organophosphorus molecule with the following structural formula:
[0010]
[0011] Where R is a hydrocarbon group.
[0012] This invention provides a method for preparing a high-temperature resistant slow-release retarder, comprising the following steps:
[0013] S100. In a reaction vessel, a measured amount of PEG is dissolved in a sufficient amount of anhydrous organic solvent, a catalyst is added, and a diacid anhydride is slowly added. While adding, the mixture is stirred and reacted at 30-50°C for 4-6 hours to generate a PEG-diacid anhydride crosslinking intermediate.
[0014] S200. Add a certain amount of HEDP to the reaction system, maintain the reaction temperature at 30-50℃, and stir continuously for 8-12 hours to form a stable HEDP-PEG crosslinking network.
[0015] S300: Remove the reaction solvent and wash the product obtained after solvent removal in anhydrous ethanol. Stir thoroughly to dissolve the residual anhydrous organic solvent and small molecule impurities. Place the washed product in a vacuum drying oven for drying to obtain HEDP-PEG high-temperature resistant slow-release retarder.
[0016] Based on the above technical solution, further, according to the molar ratio, HEDP: diacid anhydride: PEG: catalyst = 1:1:(0.5~1):(0.005~0.01).
[0017] Based on the above technical solution, further, the molecular weight of the PEG is 2000-5000, and its general structural formula is:
[0018] n = 45~110;
[0019] The HEDP is an organophosphorus molecule with the following structural formula:
[0020] .
[0021] Based on the above technical solution, the PEG-dicarboxylic anhydride crosslinking intermediate has the following structural formula:
[0022] PPEG-OC(O)-R-COOH.
[0023] Based on the above technical solution, the crosslinking agent is further described as a diacid anhydride, with the following structural formula:
[0024] RC(O)-OC(O)-R'.
[0025] Preferably, the dicarboxylic anhydride can be selected from maleic anhydride or glutaric anhydride.
[0026] Based on the above technical solution, the crosslinking agent is further selected from glutaric anhydride, citric acid, maleic anhydride, and succinic anhydride.
[0027] Based on the above technical solution, the catalyst is further described as a weak acid catalyst, and the amount used is 0.5% to 1% relative to the molar amount of diacid anhydride and HEDP.
[0028] Based on the above technical solution, further, the catalyst is benzoic acid.
[0029] Based on the above technical solution, the anhydrous organic solvent is further described as dimethylformamide or dimethyl sulfoxide.
[0030] This invention also provides an application of the HEDP-PEG high-temperature resistant slow-release retarder as described above in concrete construction.
[0031] The technical solution of the present invention has the following principles and beneficial effects:
[0032] This invention innovatively incorporates the PEG molecular structure into the HEDP molecular structure, forming a unique HEDP-PEG high-temperature resistant slow-release retarder. This molecular structure design not only retains HEDP's excellent chelating properties for calcium ions, ensuring outstanding retarding performance at high temperatures, but also leverages the temperature-sensitive properties of PEG to endow the retarder with intelligent temperature responsiveness. As temperature changes, the retarder can precisely control the release of its retarding effect, effectively avoiding the uneven release problem caused by the poor stability of traditional retarders at high temperatures, thus greatly improving the controllability and stability of its retarding performance.
[0033] The introduction of the PEG molecular structure significantly improves the dispersion performance of the retarder, ensuring its uniform distribution in the concrete system and further enhancing the consistency of the retarding effect. Simultaneously, the 3D network structure formed by the cross-linking of the two molecules acts like a robust "skeleton," greatly enhancing the overall stability of the molecules and improving the "encapsulation" of HEDP molecules by PEG. This 3D network structure, combined with the thermosensitive nature of PEG, allows for the control of the retarding effect release according to temperature changes. The network structure also facilitates the capture of calcium ions, enhancing the retarder's performance under high-temperature conditions.
[0034] In its preparation process, this invention employs a unique long-spaced-arm structure design, cleverly solving the critical problem of deactivation of the active groups in HEDP retarder due to the crosslinking reaction during synthesis. This design enables the HEDP-PEG retarder to maintain its phosphonic acid complexing ability while successfully constructing a stable crosslinking network, ensuring the maximum performance of the retarder. This represents a significant innovative breakthrough in the field of retarder synthesis processes.
[0035] Compared to traditional synthesis methods, the optimized aqueous reaction system simplifies the synthetic route and significantly reduces process complexity. Furthermore, the entire synthesis process is environmentally friendly and pollution-free, aligning with modern green chemistry trends. The reaction conditions are mild, energy consumption is low, and production costs are greatly reduced, providing solid technical support for large-scale industrial production and offering unparalleled advantages in practical applications. Detailed Implementation
[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, 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.
[0037] This invention provides the following structural examples of HEDP-PEG high-temperature resistant slow-release retarder:
[0038] ;
[0039] PEG is polyethylene glycol, with a molecular weight of 2000–5000, and its structural formula is as follows:
[0040] n = 45~110;
[0041] HEDP is an organophosphorus molecule with the following structural formula:
[0042] .
[0043] This invention also provides the following examples of methods for preparing HEDP-PEG high-temperature resistant slow-release retarder:
[0044] Example 1
[0045] Step 1: Pre-reaction of PEG and dicarboxylic anhydride
[0046] In a reaction flask, dissolve 0.05 mol (150 g) of PEG with a molecular weight of 3000 in 500 mL of DMF, ensuring the solution is homogeneous.
[0047] 0.00075 mol (0.009 g) of benzoic acid was added as a catalyst.
[0048] Slowly add 0.1 mol (11.4 g) of glutaric anhydride while stirring, and react at 30-50℃ for 4-6 hours, controlling the temperature. During this process, the anhydride groups of glutaric anhydride undergo esterification with the hydroxyl groups in PEG to generate a PEG-glutaric anhydride crosslinking intermediate.
[0049] Step 2: Add HEDP to carry out the cross-linking reaction.
[0050] After the pre-reaction of PEG-glutaric anhydride is completed, 0.1 mol (20.6 g) of HEDP is added to the reaction system.
[0051] Maintain the reaction temperature at 30-50℃ and stir continuously for 8-12 hours to allow the hydroxyl groups in HEDP to undergo esterification with the carboxyl groups of glutaric anhydride, forming a stable HEDP-PEG crosslinking network.
[0052] Step 3: Post-processing
[0053] After the reaction is complete, the reaction solvent is removed using a rotary evaporator.
[0054] The product was washed in anhydrous ethanol and stirred to dissolve residual organic solvents and small molecule impurities.
[0055] The washed product was placed in a vacuum drying oven to dry, yielding the final retarder product.
[0056] Example 2 High PEG Doping
[0057] Step 1: Pre-reaction of PEG and dicarboxylic anhydride
[0058] In a reaction flask, dissolve 0.1 mol (300 g) of PEG with a molecular weight of 3000 in 500 mL of deionized water, ensuring the solution is homogeneous.
[0059] 0.00075 mol (0.009 g) of benzoic acid was added as a catalyst.
[0060] Slowly add 0.1 mol (11.4 g) of glutaric anhydride while stirring, and react at 30-50℃ for 4-6 hours, controlling the temperature to generate PEG-glutaric anhydride crosslinking intermediate.
[0061] Step 2: Add HEDP to carry out the cross-linking reaction.
[0062] After the pre-reaction was completed, 0.1 mol (20.6 g) of HEDP was added.
[0063] Stir continuously at 30-50℃ for 8-12 hours to form a HEDP-PEG crosslinked network.
[0064] Step 3: Post-processing (same as Example 1)
[0065] Example 3 High PEG molecular weight
[0066] Step 1: Pre-reaction of PEG and dicarboxylic anhydride
[0067] In a reaction flask, 0.05 mol (150 g) of PEG with a molecular weight of 2000 was dissolved in 500 mL of deionized water to ensure that the solution was homogeneous.
[0068] 0.00075 mol (0.009 g) of benzoic acid was added as a catalyst.
[0069] Slowly add 0.1 mol (11.4 g) of glutaric anhydride while stirring, and react at 30-50℃ for 4-6 hours, controlling the temperature to generate PEG-glutaric anhydride crosslinking intermediate.
[0070] Step 2: Add HEDP to carry out the cross-linking reaction.
[0071] After the pre-reaction was completed, 0.1 mol (20.6 g) of HEDP was added.
[0072] Stir continuously at 30-50℃ for 8-12 hours to form a HEDP-PEG crosslinked network.
[0073] Step 3: Post-processing (same as Example 1)
[0074] Example 4 uses different dicarboxylic acid anhydrides
[0075] Step 1: Pre-reaction of PEG and dicarboxylic anhydride
[0076] In a reaction flask, dissolve 0.05 mol (150 g) of PEG with a molecular weight of 3000 in 500 mL of DMF, ensuring the solution is homogeneous.
[0077] 0.00075 mol (0.009 g) of benzoic acid was added as a catalyst.
[0078] Slowly add 0.1 mol (9.81 g) of maleic anhydride while stirring, and react at 30-50℃ for 4-6 hours, controlling the temperature to generate PEG-maleic anhydride crosslinking intermediate.
[0079] Step 2: Add HEDP to carry out the cross-linking reaction.
[0080] After the pre-reaction was completed, 0.1 mol (20.6 g) of HEDP was added.
[0081] Stir continuously at 30-50℃ for 8-12 hours to form a HEDP-PEG crosslinked network.
[0082] Step 3: Post-processing (same as Example 1)
[0083] Example 5: Increasing the amount of catalyst molecule added
[0084] Step 1: Pre-reaction of PEG and dicarboxylic anhydride
[0085] In a reaction flask, dissolve 0.05 mol (150 g) of PEG with a molecular weight of 3000 in 500 mL of DMF, ensuring the solution is homogeneous.
[0086] 0.001 mol (0.122 g) of benzoic acid was added as a catalyst.
[0087] Slowly add 0.1 mol (11.4 g) of glutaric anhydride while stirring, and react at 30-50℃ for 4-6 hours, controlling the temperature to generate PEG-glutaric anhydride crosslinking intermediate.
[0088] Step 2: Add HEDP to carry out the cross-linking reaction.
[0089] After the pre-reaction was completed, 0.1 mol (20.6 g) of HEDP was added.
[0090] Stir continuously at 30-50℃ for 8-12 hours to form a HEDP-PEG crosslinked network.
[0091] Step 3: Post-processing (same as Example 1)
[0092] Mortar testing and verification
[0093] Mortar tests were conducted on the five examples of products prepared at 55 degrees Celsius. Before mixing, the mortar raw materials were heated to 55 degrees Celsius; after mixing, the mortar was placed in a 55-degree Celsius oven for heat preservation, and the initial setting time was tested every 15 minutes starting from the third hour.
[0094] The mortar formula is: cement C: 400g, sand S: 800g, water W: 170g, and admixture A: 2% of the total mass of the adhesive. The admixture used is Point-S pure water-reducing admixture (without slump retention or retarding effect) produced by Kezhijie New Materials Group Co., Ltd.
[0095] Comparative Example 1 was a blank control;
[0096] Comparative Example 2 compares the addition of organophosphorus molecule HEDP as a retarder in mortar.
[0097] Comparative Example 3 compares the use of PEG and organophosphorus molecule HEDP (mixed at a molar ratio of 0.05:0.1) directly added to mortar as a retarder.
[0098] The retarder used in Comparative Example 4 was the same as that used in Example 1, but without the addition of dibasic anhydride. The rest of the preparation steps were the same as those in Example 1.
[0099] Table of fluidity and setting time of different retarder at high temperature
[0100]
[0101] The above results demonstrate that the performance of the retarder prepared in this invention was evaluated through the mortar test experiments at a high temperature of 55 degrees Celsius. The experimental results clearly show that, compared with HEDP molecules and other comparative samples, the product of this invention exhibits superior retarding performance, significantly extending the initial setting time of the mortar and demonstrating stable release. This performance advantage is of great significance in actual concrete construction, especially in large-volume concrete construction and high-temperature environments. It can effectively extend the construction operation time, ensure the quality of concrete construction, avoid various quality problems caused by premature concrete curing, and provide reliable technical support for engineering construction.
[0102] The HEDP-PEG retarder of this invention is cost-effective and easy to mass-produce, making it highly competitive in the market. Its unique thermal stability, temperature sensitivity, and slow-release properties not only meet the urgent needs of summer and high-temperature construction but also expand the application scope of concrete construction technology. For example, it has broad application prospects in projects with extremely high requirements for retarding performance, such as ultra-long-distance pumped concrete and large-scale water conservancy projects, and is expected to lead a new development trend in the field of concrete admixtures.
[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions 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 HEDP-PEG high-temperature-resistant retarding release retarder, characterized in that, The structural formula is: ； PEG is polyethylene glycol, with a molecular weight of 2000–5000, and its structural formula is as follows: ，n=45～110； HEDP stands for hydroxyethylidene diphosphonic acid, and its structural formula is as follows: ； The HEDP-PEG high-temperature resistant slow-release retarder is prepared by reacting PEG, diacid anhydride, and HEDP. The diacid anhydride is one of glutaric anhydride, maleic anhydride, and succinic anhydride, and R is a hydrocarbon group derived from the diacid anhydride.
2. A method for preparing the HEDP-PEG high-temperature resistant slow-release retarder as described in claim 1, comprising the following steps: S100. In a reaction vessel, a measured amount of PEG is dissolved in a sufficient amount of anhydrous organic solvent, a catalyst is added, and a diacid anhydride is slowly added. While adding, the mixture is stirred and reacted at 30-50°C for 4-6 hours to generate a PEG-diacid anhydride crosslinking intermediate. S200. Add a certain amount of HEDP to the reaction system, maintain the reaction temperature at 30-50℃, and stir continuously for 8-12 hours to form a stable HEDP-PEG crosslinking network. S300: Remove the reaction solvent and wash the product obtained after solvent removal in anhydrous ethanol. Stir thoroughly to dissolve the residual anhydrous organic solvent and small molecule impurities. Place the washed product in a vacuum drying oven for drying to obtain HEDP-PEG high-temperature resistant slow-release retarder.
3. The preparation method of the HEDP-PEG high-temperature resistant slow-release retarder according to claim 2, characterized in that: According to the molar ratio, HEDP : diacid anhydride : PEG : catalyst = 1 : 1 : (0.5~1) : (0.005~0.01).
4. The preparation method of the HEDP-PEG high-temperature resistant slow-release retarder according to claim 2, characterized in that: The catalyst is a weak acid catalyst, and the amount used is 0.5% to 1% relative to the molar amount of diacid anhydride and HEDP.
5. The preparation method of the HEDP-PEG high-temperature resistant slow-release retarder according to claim 2, characterized in that: The anhydrous organic solvent is dimethylformamide or dimethyl sulfoxide.
6. The application of a HEDP-PEG high-temperature resistant slow-release retarder prepared by the method of preparing the HEDP-PEG high-temperature resistant slow-release retarder as described in claim 1 or any one of claims 2-5 in concrete construction.