A high-temperature retarder for cementing and its preparation method

Abstract

This invention discloses an ultra-high temperature retarder for cementing and its preparation method; it relates to the field of oil and gas well cementing engineering technology; it solves the problems of narrow applicable temperature range, insufficient resistance to ultra-high temperature, and insufficient resistance to large temperature differences under long cementing sections in existing technologies; the retarder is prepared by copolymerization reaction of reactive monomers under the action of an initiator, and the reactive monomers include, by mass percentage: 20-30% itaconic acid, 38-48% 2-acrylamide-2-methylpropanesulfonic acid, 20-28% N,N-dimethylacrylamide, and 5-12% ethylene phosphoric acid; the retarder has good retarding performance for cement slurry under a circulating temperature of 110-230℃, which can meet a wide range of applications. Under ultra-high temperature conditions, it can effectively delay the thickening time of cement slurry without affecting the strength development of cement slurry, and the cement slurry can still have rapid strength development under large temperature difference conditions.

Description

Technical Field

[0001] This invention relates to the field of oil and gas well cementing engineering technology, specifically to an ultra-high temperature retarder for cementing and its preparation method. Background Technology

[0002] Retarder is one of the key admixtures required for preparing cement slurry for oil and gas wells. Its function is to effectively extend the setting time of the cement slurry and maintain its liquid and pumpable state for an extended period. An ideal retarder should have a retarding effect across any temperature range, with the thickening time directly proportional to the amount added, while not significantly affecting the strength development of the cement slurry once pumped in. With the depletion of shallow, readily available resources and the continuous deepening of oilfield exploration and development, high-temperature deep and ultra-deep wells are gradually becoming the focus of exploration and development. Due to the long cementing isolation sections and high reservoir temperatures in deep and ultra-deep wells, controlling the thickening time of the cement slurry is crucial for the safety and quality of cementing operations.

[0003] Currently, commonly used cementing retarders include lignin sulfonates, organophosphates, hydroxycarboxylic acid derivatives and their salts, and synthetic polymers. Lignosulfonate retarders can be used in wells with bottomhole temperatures up to 150℃, but as they are industrial byproducts, they suffer from unstable performance, high dosage sensitivity, and sensitivity to changes in cement composition. Organophosphate retarders have the advantage of low dosage, but poor high-temperature resistance and are difficult to control. Hydroxycarboxylic acid derivatives and their salts mainly include tartaric acid, citric acid, and gluconates. Their main problem is high sensitivity, leading to a non-linear relationship between cement slurry thickening time and dosage, making adjustment difficult and increasing construction risks. Synthetic polymer retarders are the most researched type of retarder both domestically and internationally in recent years. The basic idea is to select monomers containing hydroxyl, carboxyl, and phosphorus groups—groups that are easily adsorbed by cement particles and have a strong ability to inhibit cement hydration—for copolymerization. By adjusting the monomer ratio and reaction conditions, the composition and molecular weight of the synthesized polymer can be controlled, optimizing product performance and ultimately synthesizing a synthetic polymer retarder with high-temperature resistance.

[0004] There are numerous studies on the synthesis of polymer retarders in existing technologies. For example, Yang Boyong et al. synthesized the retarder MAM using AMPS and maleic acid (MAH) as monomers, with a temperature resistance of 170℃. [1] Guo Jintang et al. developed a binary copolymer-type high-temperature retarder using AMPS and a polycarboxylic acid containing unsaturated bonds as monomers, with a maximum service temperature of 180℃. [2]Tiemeyer et al. developed an AMPS-based binary high-temperature retarder by adjusting the synthesis ratio of AMPS and IA, achieving a temperature resistance of 200℃. Su Rujun et al. also synthesized a binary copolymer P(AMPS / IA) type high-temperature retarder through free radical aqueous solution polymerization, with a suitable temperature range of 60-180℃. [3] .

[0005] However, current synthetic polymer retarders still have the following problems: First, the stable temperature resistance of existing retarders is generally below 180℃, and their applicable temperature range is narrow, with insufficient resistance to ultra-high temperatures. When used under ultra-high temperature conditions, they often exhibit unstable retardation effects, require large dosages, and are highly sensitive. Second, to meet the cementing requirements of deep and ultra-deep wells under high circulation temperatures, a large amount of high-temperature retarders needs to be added to the cement slurry. Under long cementing sections, the existing retarders are insufficient in their ability to withstand large temperature differences, often leading to slow strength development or excessive retardation of the top cement slurry. Therefore, it is evident that there is still room for further improvement in current synthetic polymer retarders.

[0006] [1] Yang Boyong, Zhang Jinsheng, Li Lihua, Wang Guangying. Evaluation of MAM copolymer as a retarder for oil well cement [J]. Chemical Industry and Engineering Technology, 2012, (05): 19-23.

[0007] [2] Guo Jintang, Liu Jianjun, Jin Jianzhou, Yu Yongjin. Performance study of novel high-temperature retarder HTR-200C for cementing [J]. Journal of Tianjin University, 2012, (06): 529-534.

[0008] [3] Su Rujun, Li Qingzhong. Research and application of high temperature retarder GH-9 [J]. Drilling Fluids and Completion Fluids, 2005, (S1). Summary of the Invention

[0009] To address the technical problems existing in the prior art, the present invention provides an ultra-high temperature retarder for cementing and its preparation method. The retarder has a wide applicable temperature range, high temperature resistance, low sensitivity, controllable retarding, and no effect on the rheology, water loss, or strength of the cementing slurry system.

[0010] The technical solution adopted in this invention is as follows:

[0011] A high-temperature retarder for cementing. The retarder is prepared by copolymerization of reactive monomers under the action of an initiator, wherein the reactive monomers comprise, by mass percentage: 20-30% itaconic acid (IA), 38-48% 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 20-28% N,N-dimethylacrylamide (DMAA), and 5-12% ethylenephosphoric acid (VA).

[0012] Preferably, the reactant monomers comprise, by mass percentage: 25-28% itaconic acid (IA), 42-45% 2-acrylamide-2-methylpropanesulfonic acid (AMPS), 20-23% N,N-dimethylacrylamide (DMAA), and 7-10% ethylene phosphoric acid (VA).

[0013] More preferably, the reactant monomers comprise, by mass percentage: 25% itaconic acid (IA), 42% 2-acrylamide-2-methylpropanesulfonic acid (AMPS), 23% N,N-dimethylacrylamide (DMAA), and 10% ethylene phosphoric acid (VA).

[0014] Preferably, the amount of initiator added is equivalent to 0.3-0.8% of the total mass of the reactants, more preferably 0.3-0.5%.

[0015] Preferably, the initiator is ammonium persulfate and / or sodium persulfate.

[0016] Preferably, the initiator is an aqueous solution with a mass concentration of 2%.

[0017] Preferably, the weight-average molecular weight of the retarder is 120,000 to 140,000.

[0018] In addition, the present invention also provides a method for preparing an ultra-high temperature retarder for cementing. The preparation method includes the following steps:

[0019] Step 1: Dissolve the specified amounts of itaconic acid (IA), 2-acrylamide-2-methylpropanesulfonic acid (AMPS), and N,N-dimethylacrylamide (DMAA) in 2-3 times the mass of the monomers in deionized water, adjust the pH to 5.5-6.5, and stir until homogeneous to form a mixture.

[0020] Step 2: Place the mixture from Step 1 into a reaction apparatus equipped with a stirrer, thermometer, and nitrogen protection, and purge the oxygen from the reaction apparatus with inert gas.

[0021] Step 3: Place the reaction apparatus after purging oxygen in Step 2 into a water bath, and turn on the stirrer to heat the mixture to 58-63°C.

[0022] Step 4: Under nitrogen protection and stirring speed of 60-80 rpm, add the specified amount of initiator to the mixture at a dropping rate of 6-8 mL / min and react for 0.4-0.6 hours.

[0023] Step 5: Dissolve ethylene phosphoric acid (VA) in 1-2 times the mass of the monomer in deionized water, and add it dropwise to the mixture after the reaction in step 4 at a rate of 10-15 mL / min. Continue the reaction for 1.5-2 hours, then cool to obtain the ultra-high temperature retarder.

[0024] Preferably, the preparation method includes the following steps:

[0025] Step 1: Dissolve the specified amounts of itaconic acid (IA), 2-acrylamide-2-methylpropanesulfonic acid (AMPS), and N,N-dimethylacrylamide (DMAA) in 2.8-3 times the mass of the monomers in deionized water, adjust the pH to 6.0-6.5, and stir until homogeneous to form a mixture.

[0026] Step 2: Place the mixture from Step 1 into a reaction apparatus equipped with a stirrer, thermometer, and nitrogen protection, and purge the oxygen from the reaction apparatus with inert gas.

[0027] Step 3: Place the reaction apparatus after purging oxygen in Step 2 into a water bath, and turn on the stirrer to heat the mixture to 60-63°C.

[0028] Step 4: Under nitrogen protection and stirring speed of 70-75 rpm, add the specified amount of initiator to the mixture at a dropping rate of 6-7 mL / min and react for 0.5 hours.

[0029] Step 5: Dissolve ethylene phosphoric acid (VA) in 1.5-1.7 times the mass of the monomer in deionized water, and add it dropwise to the mixture after the reaction in step 4 at a rate of 10-12 mL / min. Continue the reaction for 2 hours and then cool to obtain the ultra-high temperature retarder.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] (1) The ultra-high temperature retarder of the present invention contains ethylene phosphoric acid (VA) and other components. The carboxyl group, sulfonic acid group, hydroxyl group and phosphate group therein act on the calcium ions of cement, which can effectively inhibit cement hydration, so that the ultra-high temperature retarder has a strong retarding effect. The retarding time is adjustable in the range of 110-230℃, and the thickening curve bulging phenomenon can be avoided.

[0032] (2) The ultra-high temperature retarder of the present invention has excellent high temperature resistance through formulation optimization, and the maximum cycling temperature can reach 230°C. One of the reasons is that the CN structure of the side chain of the added N,N-dimethylacrylamide (DMAA) monomer has high thermal energy and strong temperature resistance, and is not easy to break at high temperature.

[0033] (3) The ultra-high temperature retarder of the present invention has good retarding performance for cement slurry under the cyclic temperature conditions of 110-230℃, which can meet a wide range of applications. In particular, when the temperature reaches ultra-high temperature conditions above 180℃, it can effectively delay the thickening time of cement slurry.

[0034] (4) The ultra-high temperature retarder of the present invention can effectively extend the thickening time of cement slurry without affecting the strength development of cement slurry. Moreover, the cement slurry can also have a faster strength development under large temperature difference conditions.

[0035] (5) The ultra-high temperature retarder of the present invention has no effect on the rheology, stability, water loss and strength of the cement slurry system. Detailed Implementation

[0036] The following embodiments illustrate the invention in more detail. The invention is not limited to the following embodiments.

[0037] Example 1

[0038] A high-temperature retarder for cementing and its preparation method.

[0039] Step 1: Dissolve 5g itaconic acid (IA), 8.4g 2-acrylamide-2-methylpropanesulfonic acid (AMPS), and 4.6g N,N-dimethylacrylamide (DMAA) in three times the total mass of the monomers in deionized water, adjust the pH to 6, and stir until a mixture is formed.

[0040] Step 2: Place the mixture from Step 1 into a reaction apparatus equipped with a stirrer, thermometer, and nitrogen protection, and purge the oxygen from the reaction apparatus with inert gas.

[0041] Step 3: Place the reaction apparatus after purging oxygen in Step 2 into a water bath, and turn on the stirrer to heat the mixture to 63°C.

[0042] Step 4: Under nitrogen protection and stirring speed of 75 rpm, add ammonium persulfate solution accounting for 0.35% of the total mass of the reactants to the mixture dropwise at a rate of 6 mL / min, and react for 0.5 hours.

[0043] Step 5: Dissolve 2g of ethylene phosphoric acid (VA) in 1.5 times the mass of the monomer in deionized water, and add it dropwise to the mixture after reacting for 0.5 hours in Step 4 at a rate of 12mL / min. Continue the reaction for 2 hours and then cool to obtain an ultra-high temperature retarder with a weight-average molecular weight of 140,000.

[0044] Example 2

[0045] A high-temperature retarder for cementing and its preparation method.

[0046] Step 1: Dissolve 5.6g itaconic acid (IA), 9g 2-acrylamide-2-methylpropanesulfonic acid (AMPS), and 4g N,N-dimethylacrylamide (DMAA) in 2.8 times the total mass of the monomers in deionized water, adjust the pH to 6.5, and stir until a mixture is formed.

[0047] Step 2: Place the mixture from Step 1 into a reaction apparatus equipped with a stirrer, thermometer, and nitrogen protection, and purge the oxygen from the reaction apparatus with inert gas.

[0048] Step 3: Place the reaction apparatus after purging oxygen in Step 2 into a water bath, and turn on the stirrer to heat the mixture to 60°C.

[0049] Step 4: Under nitrogen protection and stirring speed of 70 rpm, sodium persulfate solution accounting for 0.40% of the total mass of the reactants is added dropwise to the mixture at a dropping rate of 7 ml / min, and the reaction is carried out for 0.5 hours.

[0050] Step 5: Dissolve 1.4g of ethylene phosphoric acid (VA) in 1.7 times the mass of the monomer in deionized water, and add it dropwise to the mixture after reacting for 0.5 hours in Step 4 at a rate of 10ml / min. Continue the reaction for 2 hours and then cool to obtain an ultra-high temperature retarder with a weight-average molecular weight of 120,000.

[0051] Test Example 1

[0052] The effects of the ultra-high temperature retarder of this invention on the conventional properties of cement slurry were tested according to the national standard GB / T 19139-2012 "Test Methods for Oil Well Cement" and the industry standard SY / T5504.1-2013 "Evaluation Methods for Oil Well Cement Admixtures Part 1: Retarder". The basic test formulation was: Grade G cement + 40% high-temperature reinforcing agent XNK200-2S + 3% crystal phase modifier XNK200-1S + 1.5% high-temperature suspending agent SP200S + 2% toughening agent HE-1S + 4% water loss reducing agent XNFL300L + 1.5% dispersant XNFS200L + the ultra-high temperature retarder of this invention + water. All admixtures and additives were added as a percentage of the cement mass, and the cement slurry density was 1.90 g / cm³. 3 .

[0053] Table 1 shows the test data of the effects of the ultra-high temperature retarder of the present invention on the fluidity, API water loss, settling stability and free liquid properties of cement slurry under different temperatures and dosages.

[0054] Table 1. Test results of the effect of ultra-high temperature retarder on the conventional properties of cement paste.

[0055]

[0056]

[0057] As can be seen from the results in Table 1, the ultra-high temperature retarder of Examples 1 and 2 of the present invention has no effect on the basic properties of cement slurry, such as API water loss, free liquid, and density difference between the upper and lower parts.

[0058] Test Example 2

[0059] The retarding performance of the ultra-high temperature retarder of this invention was tested according to the national standard GB / T 19139-2012 "Test Methods for Oil Well Cement" and the industry standard SY / T5504.1-2013 "Evaluation Methods for Oil Well Cement Admixtures Part 1: Retarder". The basic formula for the test was: Grade G cement + 40% high-temperature reinforcing agent XNK200-2S + 3% crystal phase modifier XNK200-1S + 1% high-temperature suspending agent SP200S + 2% toughening agent HE-1S + water loss reducing agent XNFL300L + 1.5% dispersant XNFS200L + the ultra-high temperature retarder of this invention + water. The dosage of all admixtures and additives was calculated as a percentage of the cement mass, and the cement paste density was 1.90 g / cm³. 3 .

[0060] The test data on the effect of the ultra-high temperature retarder of the present invention on the thickening time of cement paste under different temperature and pressure conditions are shown in Table 2.

[0061] Table 2. Test results of the retarding performance of ultra-high temperature retarder

[0062]

[0063] As can be seen from the results in Table 2, the ultra-high temperature retarder of Examples 1 and 2 of the present invention has good retarding performance for cement slurry under the cyclic temperature conditions of 110-230℃, which can meet a wide range of applications. In particular, when the temperature reaches ultra-high temperature conditions above 180℃, it can effectively delay the thickening time of cement slurry.

[0064] Test Example 3

[0065] The dosage sensitivity and temperature sensitivity of the ultra-high temperature retarder of this invention were tested according to the national standard GB / T 19139-2012 "Test Methods for Oil Well Cement" and the industry standard SY / T5504.1-2013 "Evaluation Methods for Oil Well Cement Admixtures Part 1: Retarder". The basic formula for the test was: Grade G cement + 40% high-temperature reinforcing agent XNK200-2S + 3% crystal phase modifier XNK200-1S + 1% high-temperature suspending agent SP200S + 2% toughening agent HE-1S + water loss reducing agent XNFL300L + 1.5% dispersant XNFS200L + the ultra-high temperature retarder of this invention + water. The dosage of all admixtures and additives was calculated as a percentage of the cement mass, and the cement paste density was 1.90 g / cm³. 3 .

[0066] According to SY / T 5504.1-2013 "Evaluation Method of Oil Well Cement Admixtures Part 1: Retarder", the dosage sensitivity test of retarder is as follows: for a reference formula below a certain representative temperature point, the dosage of retarder is increased by 10% and a thickening test is conducted. The dosage sensitivity of retarder is calculated according to the following formula, and the dosage sensitivity of retarder is required to be ≤25%.

[0067] R D =(t D -t P ) / t P *100%

[0068] In the formula R D Sensitivity to retarder dosage; t D To increase the thickening time of cement slurry under a 10% increase in dosage, [min; t] P Thickening time, in minutes, is the reference formulation.

[0069] The dosage sensitivity of the ultra-high temperature retarder of the present invention was tested under representative temperatures of 150℃ and 210℃, and the results are shown in Table 3.

[0070] Table 3. Results of the Dosage Sensitivity Test for Ultra-High Temperature Retarder

[0071]

[0072]

[0073] As shown in Table 3, when the amount of retarder increases by 10%, the change rate of cement paste thickening time is less than 10%, which is far less than the standard requirement of 25%.

[0074] According to SY / T 5504.1-2013 "Evaluation Method of Oil Well Cement Admixtures Part 1: Retarder", the temperature sensitivity test of the retarder is as follows: for a reference formulation at a certain representative temperature point, the test temperature is increased by 5°C to conduct a thickening test, and the temperature sensitivity of the retarder is calculated according to the following formula. The temperature sensitivity of the retarder is required to be ≤20%.

[0075] R T =t P -t T / / t P *100%

[0076] In the formula R T Temperature sensitivity of retarder; t P Thickening time (min) for the baseline formulation; t T The thickening time of cement slurry under the condition of increasing the test temperature by 5℃ is measured in minutes.

[0077] The temperature sensitivity of the ultra-high temperature retarder of the present invention was tested under representative temperatures of 150℃ and 210℃, and the results are shown in Table 4.

[0078] Table 4. Temperature sensitivity test results of ultra-high temperature retarder

[0079]

[0080] As shown in Table 4, when the test temperature increases by 5℃, the change rate of cement paste thickening time is less than 10%, which is far less than the standard requirement of 20%.

[0081] Test Example 4

[0082] The influence of the ultra-high temperature retarder of this invention on the strength development of cement slurry was tested according to the national standard GB / T 19139-2012 "Test Methods for Cement in Oil Wells" and the industry standard SY / T5504.1-2013 "Evaluation Methods for Admixtures in Oil Well Cement Part 1: Retarder". The basic formula for the test was: Grade G cement + 40% high-temperature reinforcing agent XNK200-2S + 3% crystal phase modifier XNK200-1S + 1% high-temperature suspending agent SP200S + 2% toughening agent HE-1S + water loss reducing agent XNFL300L + 1.5% dispersant XNFS200L + the ultra-high temperature retarder of this invention + water. The dosage of all admixtures and additives was calculated as a percentage of the cement mass, and the cement slurry density was 1.90 g / cm³. 3 .

[0083] Table 5. Test results of the effect of ultra-high temperature retarder on cement paste strength.

[0084]

[0085] As can be seen from the data in Table 5, the ultra-high temperature retarder of the present invention can effectively extend the thickening time of cement slurry without affecting the strength development of cement slurry. Moreover, the cement slurry can also have a relatively fast strength development under large temperature difference conditions.

[0086] Finally, it should be noted that the above specific embodiments and corresponding test examples are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can modify or make equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An ultra-high temperature retarder for cementing, characterized by, The retarder is prepared by copolymerization of the reaction monomers under the action of the initiator, and the reaction monomers comprise, in percentage by mass, 20-30% itaconic acid, 38-48% 2-acrylamido-2-methylpropanesulfonic acid, 20-28% N,N-dimethylacrylamide, and 5-12% ethylene phosphoric acid.

2. The ultra-high temperature retarder for cementing as claimed in claim 1, wherein, The reaction monomers comprise, in percentage by mass, 25-28% itaconic acid, 42-45% 2-acrylamido-2-methylpropanesulfonic acid, 20-23% N,N-dimethylacrylamide, and 7-10% ethylene phosphoric acid.

3. The ultra-high temperature retarder for cementing according to claim 2, characterized in that, The reaction monomers comprise, in percentage by mass, 25% itaconic acid, 42% 2-acrylamido-2-methylpropanesulfonic acid, 23% N,N-dimethylacrylamide, and 10% ethylene phosphoric acid.

4. The ultra-high temperature retarder for cementing as claimed in claim 1, wherein, The initiator is added in an amount equivalent to 0.3-0.8% of the total mass of the reaction monomers.

5. The ultra-high temperature retarder for cementing according to claim 4, characterized in that, The initiator is added in an amount equivalent to 0.3-0.5% of the total mass of the reaction monomers.

6. The ultra-high temperature retarder for cementing as claimed in claim 1, wherein, The initiator is ammonium persulfate and / or sodium persulfate.

7. The ultra-high temperature retarder for cementing according to claim 6, characterized in that, The initiator is a water solution with a mass concentration of 2%.

8. The ultra-high temperature retarder for cementing as claimed in claim 1, wherein, The retarder has a weight average molecular weight of 120-140 thousand.

9. The method for preparing an ultra-high temperature retarder for cementing according to any one of claims 1-8, characterized in that, The preparation method comprises the following steps: Step 1: Dissolve the itaconic acid, 2-acrylamido-2-methylpropanesulfonic acid, and N,N-dimethylacrylamide in a total amount in deionized water in an amount equivalent to 2-3 times the mass of the monomers, adjust the pH to 5.5-6.5, and stir uniformly to form a mixed solution; Step 2: Place the mixed solution in step 1 in a reaction device provided with a stirrer, a thermometer, and a nitrogen protection condition, and introduce inert gas to exhaust the oxygen in the reaction device; Step 3: Place the reaction device after the oxygen is exhausted in step 2 in a water bath, and start the stirrer to heat the mixed solution to 58-63℃; Step 4: Under the conditions of a stirring rate of 60-80 revolutions per minute and nitrogen protection, add the initiator in a specified amount to the mixed solution at a drop rate of 6-8 mL / min, and react for 0.4-0.6 hours; Step 5: Dissolve the ethylene phosphoric acid in deionized water in an amount equivalent to 1-2 times the mass of the monomers, and add it to the mixed solution after the reaction in step 4 at a drop rate of 10-15 mL / min, continue to react for 1.5-2 hours, and then cool to obtain the ultra-high temperature retarder.

10. The method of claim 9, wherein the superhigh-temperature retarder for cementing is prepared by adding 0.1 to 0.5 parts by weight of the compound of formula 1 to 100 parts by weight of a carrier. The preparation method comprises the following steps: Step 1: Dissolve the itaconic acid, 2-acrylamido-2-methylpropanesulfonic acid, and N,N-dimethylacrylamide in a total amount in deionized water in an amount equivalent to 2-3 times the mass of the monomers, adjust the pH to 5.5-6.5, and stir uniformly to form a mixed solution; Step 2: Place the mixed solution in step 1 in a reaction device provided with a stirrer, a thermometer, and a nitrogen protection condition, and introduce inert gas to exhaust the oxygen in the reaction device; Step 3: Place the reaction device after the oxygen is exhausted in step 2 in a water bath, and start the stirrer to heat the mixed solution to 58-63℃; Step 4: Under the conditions of a stirring rate of 60-80 revolutions per minute and nitrogen protection, add the initiator in a specified amount to the mixed solution at a drop rate of 6-8 mL / min, and react for 0.4-0.6 hours; Step 5: Dissolve the ethylene phosphoric acid in deionized water in an amount equivalent to 1-2 times the mass of the monomers, and add it to the mixed solution after the reaction in step 4 at a drop rate of 10-15 mL / min, continue to react for 1.5-2 hours, and then cool to obtain the ultra-high temperature retarder. Step 5: Vinyl phosphoric acid (VA) is dissolved in 1.5-1.7 times of deionized water relative to the mass of monomers, and is added dropwise to the mixture after the reaction in step 4 at a dropwise rate of 10-12 mL / min, and after 2 hours of continuous reaction, cooling is performed to obtain an ultra-high temperature retarder.

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