Anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive and preparation method and application thereof

Abstract

The invention relates to an anti-mud and water-retaining polycarboxylic acid slump-retaining agent additive and a preparation method and application thereof. The preparation method of the anti-mud and water-retaining polycarboxylic acid slump-retaining agent additive comprises the following steps: blending an unsaturated acid, phenyl dichlorophosphate, and a mercaptan, adding a catalyst and an inhibitor, and performing an esterification reaction at 100 to 120° C. for 6 to 8 hours to obtain an anti-mud and water-retaining polycarboxylic acid slump-retaining agent additive. After hydrolysis of the thiol ester on the main chain of the slump-retaining agent of the invention, the adsorption of mud, stone powder, etc. on a water-reducing agent can be effectively reduced, and the long-term retention capacity of concrete can be improved. The problem of rapid slump loss of concrete caused by high mud content in sand and gravel in the current market can be effectively solved, and the production cost of concrete enterprises can be reduced. The anti-mud and water-retaining polycarboxylic acid slump-retaining agent prepared by the invention has a good anti-adsorption effect on sand and gravel materials containing kaolin, bentonite, and basalt stone powder, and has outstanding water retention performance, small concrete slump loss, strong market orientation, and is conducive to rapid promotion and application.

Description

Technical Field

[0001] The invention relates to the technical field of concrete admixtures, and in particular to an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive and a preparation method and application thereof. Background Art

[0002] With the rapid development of the domestic construction industry, the supply of raw materials such as sand and gravel for concrete is tight, and the quality of sand and gravel has dropped significantly. In particular, sand with high mud content and crushed stone with high stone powder content are widely used in the market, resulting in increased slump loss of concrete, a significant increase in the amount of water reducer, and increased costs for concrete production companies. Therefore, the market demand for anti-mud and anti-stone powder polycarboxylic acid water reducers continues to increase.

[0003] In recent years, the industry has generally adopted methods such as increasing the amount of water reducer or adding water to concrete to solve the problem of concrete slump loss caused by high sand and gravel content. On the one hand, this has increased the operating costs of concrete companies, and on the other hand, the secondary water addition has caused a significant decrease in the strength and durability of concrete, endangering public safety. At present, polycarboxylate water reducer is an important component of concrete. Due to its large adjustable space of molecular structure and the ability to design molecular structure according to different needs, it has become the preferred solution to solve the problem of concrete slump loss.

[0004] At present, the development of anti-mud polycarboxylic acid water-reducing agent products on the market mainly solves this problem by modifying water-reducing agents and making the side chains of water-reducing agent molecules branched to preferentially adsorb mud. After the side chain branching is improved, the side chain structure of the water-reducing agent molecule is complex, and the molecular chain is prone to curling, which affects the performance of the water-reducing agent. Therefore, its anti-mud performance is poor or the cost of using the water-reducing agent is high.

[0005] The Chinese invention patent with publication number CN112876667B discloses a ferrocene-modified polyoxyethylene ether monomer and a ferrocene-modified anti-mud polycarboxylic acid water reducer, which utilizes the steric hindrance of the ferrocene group on the long side chain of the polymer to inhibit the surface adsorption and intercalation adsorption of clay on the polycarboxylic acid water reducer, thereby improving the water reducer's anti-adsorption ability on clay. However, it lacks a carboxyl protective functional group, so its slump retention performance is not excellent enough.

[0006] The specific preparation methods other than anti-mud are as follows: (1) preparing ferrocene-modified polyoxyethylene ether monomer by ring-opening polymerization reaction of ferrocene-containing epoxy monomer and ethylene oxide under the joint action of ene alcohol and catalyst; (2) preparing ferrocene-modified polyoxyethylene ether monomer, unsaturated acid or its derivative monomer by free radical random copolymerization reaction under the joint action of initiator, reducing agent and chain transfer agent. The polycarboxylic acid water reducer prepared by the method of the present invention is an anti-mud polycarboxylic acid water reducer, which uses the steric hindrance of ferrocene group on the long side chain of polymer to inhibit the surface adsorption and intercalation adsorption of clay on polycarboxylic acid water reducer, thereby improving the anti-adsorption capacity of water reducer on clay. A viscosity-reducing water reducer synthesized by polymerization reaction of maleic anhydride-modified phosphate, the patent requires the esterification condensation of maleic anhydride, polyethylene glycol, etc., the esterification process has strict requirements, and the esterification rate fluctuates greatly, the production cost is high, the process is relatively complicated, and it is not conducive to industrial production.

[0007] The Chinese invention patent with publication number CN109721722A discloses a viscosity-reducing polycarboxylic acid water-reducing agent containing a double viscosity-reducing functional group. The viscosity-reducing functional group used is a straight-chain structure, which has a high water reduction rate, good collapse retention performance, is conducive to production, and has a significant viscosity-reducing effect. However, the straight-chain viscosity-reducing functional group has a poorer viscosity-reducing effect than the cyclic viscosity-reducing functional group.

[0008] The Chinese invention patent with publication number CN112795022A discloses a crack-resistant shrinkage-reducing polycarboxylic acid water-reducing agent, which is a shrinkage-reducing polycarboxylic acid water-reducing agent with gallic acid as a functional polymerization monomer. The gallic acid undergoes a free radical polymerization reaction in the form of carboxyl condensation, and the obtained water-reducing agent has a significant shrinkage-reducing effect. However, the polyhydroxy structure thereof requires hydroxyl protection before polymerization, which increases the reaction steps and complicates the production. In addition, the viscosity-reducing effect of the product is not significant. Summary of the invention

[0009] In view of this, it is necessary to provide an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive and a preparation method and application thereof to address the above problems.

[0010] The present invention is achieved through the following technical solutions:

[0011] In a first aspect, the present invention provides a method for preparing an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive, comprising the following steps:

[0012] Unsaturated acid, phenyl dichlorophosphate and mercaptan are mixed, a catalyst and an inhibitor are added, and an esterification reaction is carried out at 100-120° C. for 6-8 hours to obtain an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive.

[0013] Furthermore, the molar ratio of the unsaturated acid, the phenyl dichlorophosphate and the thiol is 1:1:1.

[0014] Furthermore, the thiol is any one of ethanethiol, ethanedithiol, 1-propanethiol, 1,3-propanedithiol, and dihydroxypropanethiol.

[0015] Furthermore, the catalyst is one of pyridine, concentrated sulfuric acid, p-toluenesulfonic acid, stannous oxide, and dibutyltin oxide.

[0016] Furthermore, the polymerization inhibitor is p-hydroxyanisole, hydroquinone or phenothiazine.

[0017] In a second aspect, the present invention provides an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive, which is prepared by the preparation method described in the first aspect above.

[0018] In a third aspect, the present invention provides the use of an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive in the preparation of a collapse-preventing agent.

[0019] In a fourth aspect, the present invention provides a method for preparing an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent, comprising the following steps:

[0020] ① Preparing a mixed solution: mixing the collapse retaining agent additive described in the second aspect with a cross-linking monomer, an unsaturated hydroxy ester, an unsaturated acid, a chain transfer agent and water to obtain a mixed solution;

[0021] ② Mix the unsaturated polyether and water, stir and disperse them evenly; add the oxidant and ferrous sulfate solution at one time, and after 5 to 20 minutes, add the reducing agent and the mixed solution. After the addition is completed, keep warm for 30 to 60 minutes;

[0022] ③Adjust the pH to 6-7.

[0023] Furthermore, the mass ratio of the collapse retaining agent additive, the cross-linking monomer, the unsaturated hydroxy ester, the unsaturated acid and the chain transfer agent in the mixed solution is 20-25:3-5:8-10:6:1-3.

[0024] Furthermore, in step ②, the amount of the oxidant added is 2%-5% of the mass of the unsaturated polyether, the amount of the ferrous sulfate solution added is 1%-3% of the mass of the unsaturated polyether, and the amount of the reducing agent added is 10%-15% of the mass of the unsaturated polyether.

[0025] Furthermore, the mass ratio of the unsaturated polyether to the collapse-preventing agent additive is 1:(0.2-0.25).

[0026] In a fifth aspect, the present invention provides an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent, which is prepared by the preparation method described in the third aspect above.

[0027] The advantages and beneficial effects of the present invention are:

[0028] 1. The present invention discloses a mud-resistant and water-retaining polycarboxylic acid slump-retaining agent. The unsaturated thiol ester is prepared by a dehydration condensation reaction between an unsaturated acid, phenyl dichlorophosphate and a mercaptan. The unsaturated thiol ester is then copolymerized with an unsaturated ether, an unsaturated acid, a crosslinking agent and an unsaturated hydroxy ester to obtain a water-reducing agent product that can resist the molecular adsorption of mud or stone powder on the water-reducing agent, improve the slump-retaining performance of concrete, thereby reducing the amount of concrete water-reducing agent used, effectively reducing the operating costs of concrete enterprises, and facilitating the construction of high-mud concrete; improving the efficiency of concrete construction.

[0029] 2. The anti-mud and water-retaining polycarboxylic acid slump-retaining agent of the present invention uses thiol ester as part of the side chain to increase the steric hindrance effect, resist the adsorption of the soil layered structure on the water-reducing agent molecules, improve the product's anti-mud ability, and reduce the slump loss of concrete caused by soil adsorption.

[0030] 3. The anti-mud and water-retaining polycarboxylic acid slump retaining agent of the present invention uses thiol ester as part of the side chain. The electrostatic repulsion of the thiol group generated after the ester group is hydrolyzed is stronger, thereby increasing the slump retention ability of the concrete after 2 hours.

[0031] 4. The anti-mud and water-retaining polycarboxylic acid slump retaining agent of the present invention is added with a cross-linking monomer and an unsaturated hydroxy ester, which further improves the slump retaining performance of concrete after hydrolysis and reduces the slump loss during pumping. DETAILED DESCRIPTION

[0032] In order to make the purpose, 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 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.

[0033] In order to solve the problem of concrete slump loss caused by high sand and gravel mud content, the industry generally adopts methods such as increasing the amount of water reducer or adding water to concrete twice. As an important component of concrete, polycarboxylate water reducer has a large adjustable space for its molecular structure and can be designed according to different needs, so it has become the preferred solution to the problem of concrete slump loss.

[0034] In view of this, the embodiments of the present application provide an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive and a preparation method and application thereof.

[0035] In a first aspect, the present invention provides a method for preparing an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive, comprising the following steps:

[0036] Unsaturated acid, phenyl dichlorophosphate and mercaptan are mixed, a catalyst and an inhibitor are added, and an esterification reaction is carried out at 100-120°C for 6-8 hours to obtain an esterification product, thiol ester, which is an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive.

[0037] Taking pyridine as a catalyst as an example, the esterification reaction formula is as follows:

[0038]

[0039] R is an olefin group, RCOOH is an unsaturated acid, specifically at least one of cinnamic acid, acrylic acid, methacrylic acid, maleic acid, and itaconic acid. R' is -CH3. PDCP represents phenyl dichlorophosphate, and Py represents pyridine. The role of pyridine is to react with HCl generated simultaneously during the generation of the intermediate, thereby continuously promoting the reaction.

[0040] The carboxyl group of the unsaturated acid and the hydroxyl group of the thiol undergo a dehydration condensation reaction or an esterification reaction. Since the esterification yield of this step is low, phenyl dichlorophosphate is introduced to first undergo an exchange reaction with the unsaturated acid to produce hydrochloric acid and unsaturated acid phenyl phosphate, and then undergo an exchange reaction with the thiol to obtain the product thiol ester.

[0041] Furthermore, the molar ratio of the unsaturated acid, the phenyl dichlorophosphate and the thiol is 1:1:1.

[0042] Furthermore, the unsaturated acid is at least one of cinnamic acid, acrylic acid, methacrylic acid, maleic acid and itaconic acid.

[0043] The thiol is any one of ethanethiol, ethanedithiol, 1-propanethiol, 1,3-propanedithiol, and dihydroxypropanethiol.

[0044] The catalyst is one of pyridine, concentrated sulfuric acid, p-toluenesulfonic acid, stannous oxide and dibutyltin oxide. The mass of the catalyst is 3% to 5% of the total mass of all raw materials for the esterification reaction.

[0045] The polymerization inhibitor is p-hydroxyanisole, hydroquinone or phenothiazine. The mass of the polymerization inhibitor is 0.1% to 0.5% of the total mass of all raw materials for the esterification reaction.

[0046] In a second aspect, the present invention provides an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive, which is prepared by the preparation method of the anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive.

[0047] In a third aspect, the present invention provides the use of an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive in the preparation of a collapse-preventing agent.

[0048] In a fourth aspect, the present invention provides a method for preparing an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent, comprising the following steps:

[0049] ① Preparing a mixed solution: mixing the collapse retaining agent additive described in the second aspect with a cross-linking monomer, an unsaturated hydroxy ester, an unsaturated acid, a chain transfer agent and water to obtain a mixed solution;

[0050] ② Mix the unsaturated polyether and water, stir and disperse them evenly; add the oxidant and ferrous sulfate solution at one time, and after 5 to 20 minutes, add the reducing agent and the mixed solution. After the addition is completed, keep warm for 30 to 60 minutes;

[0051] ③Adjust the pH to 6-7.

[0052] The copolymerization reaction is an organic addition reaction of the polyether macromonomer with the opening double bonds of unsaturated acids and unsaturated esters, and the molecular weight of the product can be designed.

[0053] The addition reaction equation of unsaturated polyether and unsaturated acid is as follows:

[0054]

[0055] Its reaction mechanism is: when the oxidant is used as the initiator, the double bonds of the unsaturated polyether and the unsaturated acid are opened to perform an addition reaction, wherein the addition of ferrous sulfate and the reducing agent and the oxidant undergo a redox reaction, releasing energy, reducing the energy required for the addition reaction, and helping to increase the reaction rate of the addition reaction; therefore, its reaction is an addition reaction of the polyether and the unsaturated acid, the oxidant and the reducing agent, and the ferrous sulfate are matched as a redox system, and the divalent ferrous acid can be oxidized and reduced, and exists as an initiation system for the polymerization reaction to promote the polymerization reaction rate. It is only for initiating the addition reaction and increasing the reaction rate, and it does not participate in the addition reaction itself.

[0056] Furthermore, the mass ratio of the collapse-preventing agent additive, the cross-linking monomer, the unsaturated hydroxy ester, the unsaturated acid and the chain transfer agent in the mixed solution is 20-25:3-5:8-10:6:1-3.

[0057] In step ②, the amount of water added is 80% to 100% of the mass of the unsaturated polyether, the amount of the oxidant added is 2% to 5% of the mass of the unsaturated polyether, the amount of the ferrous sulfate solution added is 1% to 3% of the mass of the unsaturated polyether, and the amount of the reducing agent added is 10% to 15% of the mass of the unsaturated polyether;

[0058] The mass ratio of the unsaturated polyether to the collapse-preventing agent additive is 1:(0.2-0.25).

[0059] The mass concentration of the ferrous sulfate solution is 0.3% to 1%.

[0060] The cross-linking monomer is polyethylene glycol monomaleate or polyethylene glycol acrylate, and the polyethylene glycol is PEG-200, PEG-400, PEG-600 or PEG-800.

[0061] The unsaturated polyether is allyl polyoxyethylene ether (APEG), methyl allyl alcohol polyoxyethylene ether (HPEG) or isopentanol polyoxyethylene ether (TPEG), and the molecular weight of the unsaturated polyether is 3000-4500.

[0062] The unsaturated hydroxy ester is any one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate and hydroxypropyl methacrylate.

[0063] The chain transfer agent is any one of mercaptoacetic acid, mercaptoethanol, 2-mercaptopropionic acid, 3-mercaptopropionic acid, 2-mercaptosuccinic acid, sodium methyl propene sulfonate, and 2-acrylamide-2-methylpropane sulfonic acid.

[0064] The unsaturated acid is at least one of cinnamic acid, acrylic acid, methacrylic acid, maleic acid and itaconic acid.

[0065] The oxidant is persulfate or hydrogen peroxide; the persulfate is any one of ammonium persulfate, sodium persulfate and potassium hydrogen persulfate.

[0066] The reducing agent is hypophosphite or L-ascorbic acid, and the hypophosphite is any one of sodium hypophosphite, potassium hypophosphite, calcium hypophosphite and ferric hypophosphite.

[0067] In a fifth aspect, the present invention provides an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent, which is prepared by the preparation method of the anti-mud and water-retaining polycarboxylic acid collapse-preventing agent.

[0068] The anti-mud and water-retaining polycarboxylic acid slump-retaining agent synthesized by the present invention can effectively reduce the adsorption of mud, stone powder and the like on the water-reducing agent after hydrolysis of the thiol ester on the main chain, improve the long-term retention capacity of concrete, and effectively solve the problem of rapid slump loss of concrete caused by high mud content in sand and gravel in the current market, thereby reducing the production cost of concrete enterprises. The anti-mud and water-retaining polycarboxylic acid slump-retaining agent prepared by the present invention has a good anti-adsorption effect on sand and gravel materials containing kaolin, bentonite and basalt stone powder, and has outstanding water retention performance, small concrete slump loss, strong market orientation, and is conducive to rapid promotion and application.

[0069] The following is a detailed introduction to the preparation method of a mud-resistant and water-retaining polycarboxylic acid collapse-preventing agent provided in the embodiment of the present application:

[0070] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.

[0071] Examples 1-7

[0072] Examples 1-7 each provide a kind of anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive and a method for preparing a collapse-preventing agent using the additive:

[0073] (1) Preparation of anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive by esterification reaction:

[0074] Unsaturated acid, phenyl dichlorophosphate and mercaptan are mixed in a molar ratio of 1:1:1, a catalyst and an inhibitor are added, and an esterification reaction is carried out at 100-120°C for 6-8 hours to obtain an esterification product, thiol ester, which is an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive.

[0075] (2) Preparation of anti-mud and water-retaining polycarboxylic acid collapse-preserving agent by copolymerization:

[0076] ① Preparing a mixed solution: mixing the collapse-preventing agent additive prepared in step (1) with a crosslinking monomer, an unsaturated hydroxy ester, an unsaturated acid, a chain transfer agent and 10 g of water to obtain a mixed solution;

[0077] ② Add 100g of unsaturated polyether with a molecular weight of 3000 and water into the reactor, stir and disperse evenly; add the oxidant and 0.3% to 1% ferrous sulfate solution at one time, and after 5 to 20 minutes, first add the reducing agent and the mixed solution dropwise, and after the addition is completed, keep warm for 30 minutes;

[0078] ③Add 32% liquid alkali to neutralize to pH=6-7, and add water to 40% solid content.

[0079] The differences in the feeding and control parameters of the reaction process are shown in Table 1:

[0080] Table 1

[0081]

[0082]

[0083]

[0084]

[0085] Comparative Example 1

[0086] This comparative example provides an anti-mud and water-retaining polycarboxylic acid collapse inhibitor additive and a method for preparing a collapse inhibitor using the additive. The difference between this comparative example and Example 1 is only that acrylic acid is replaced by acetic acid in the esterification reaction in step (1), and the rest is the same as Example 1.

[0087] Comparative Example 2

[0088] This comparative example provides an anti-mud and water-retaining polycarboxylic acid slump-preventing agent additive and a method for preparing a slump-preventing agent using the additive. The difference between this comparative example and Example 1 is only that in the esterification reaction of step (1), acrylic acid, phenyl dichlorophosphate, and ethanedithiol are blended in a molar ratio of 1:2:3, and the rest is the same as Example 1.

[0089] Comparative Example 3

[0090] This comparative example provides an anti-mud and water-retaining polycarboxylic acid slump-preventing agent additive and a method for preparing a slump-preventing agent using the additive. The difference between this comparative example and Example 1 is only that pyridine is replaced with ethylenediamine in the esterification reaction in step (1), and the rest is the same as Example 1.

[0091] Comparative Example 4

[0092] This comparative example provides an anti-mud and water-retaining polycarboxylic acid slump-retaining agent additive and a method for preparing a slump-retaining agent using the additive. The difference between this comparative example and Example 1 is only that: in step (2) of the copolymerization reaction, no ferrous sulfate solution is added, and the rest is the same as Example 1.

[0093] The polycarboxylic acid slump retaining agents prepared in Examples 1 to 7 and the polycarboxylic acid slump retaining agents prepared in Comparative Examples 1 to 4 were mixed into concrete, and the amount of the slump retaining agents in the concrete was 0.16% of the concrete cementitious material. The slump retention capacity of the concrete was tested to compare the effects of different slump retaining agents on the performance of the concrete.

[0094] The sand used in the concrete test is Mx=2.1, with a mud content of 8%, the stone is 5-31.5mm continuously graded basalt crushed stone, the cement is Jingyang Jidong 42.5 ordinary Portland cement, and the fly ash is Datang Shenglong Grade II ash. The concrete performance test is carried out in accordance with GB / T 50080-2016 "Standard for Test Methods for Performance of Ordinary Concrete Mixtures".

[0095] The concrete mix ratio is shown in Table 2 Concrete mix ratio.

[0096] The comparative results of concrete tests are shown in Table 3 Concrete test results.

[0097] Table 2 Concrete mix ratio Unit: kg / m 3

[0098]

[0099] Table 3 Concrete test results

[0100]

[0101]

[0102] According to the performance test data of concrete mixed with different slump retainers in Table 3, the concrete mixed with samples of Examples 1 and 2 in the present invention, which added phenyl phosphate during polymerization, had good slump retention ability for 1h and 2h. After acrylic acid was replaced with maleic acid in Example 3, the slump retention ability of concrete was slightly reduced; the slump retention ability of samples of Examples 4, 5, 6, and 7 for 2h was slightly reduced, mainly due to the adjustment of the catalyst for the first esterification reaction, which led to a decrease in the esterification rate. In Comparative Example 1, acrylic acid was replaced with acetic acid. Because acetic acid lacked double bonds, the reaction product could not participate in the polymerization in the second step, resulting in a large loss of slump in the sample concrete for 1h and 2h; in Comparative Example 2, due to the large change in the molar ratio of the esterification material, the corresponding esterification reaction could not be completely carried out, and the slump loss of the concrete was large; in Comparative Example 3, after pyridine was replaced with ethylenediamine, the esterification reaction was difficult to carry out, and the performance of the polymerized slump retainer decreased; in Comparative Example 4, after the removal of ferrous sulfate, the conversion rate of the second polymerization reaction decreased, so the performance of the synthesized slump retainer decreased.

[0103] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a polycarboxylic acid anti-sludge and water-retaining collapse-preventing agent additive, characterized in that: The following steps are involved: The unsaturated acid, phenyl dichlorophosphate and mercaptan are mixed, a catalyst and an inhibitor are added, and an esterification reaction is carried out at 100-120°C for 6-8 hours to obtain an anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive. The catalyst is one of pyridine, concentrated sulfuric acid, p-toluenesulfonic acid, stannous oxide and dibutyltin oxide.

2. The method for preparing the anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive according to claim 1, characterized in that: The molar ratio of the unsaturated acid, the phenyl dichlorophosphate and the thiol is 1:1:

1.

3. The method for preparing the anti-mud and water-retaining polycarboxylic acid collapse-preventing agent additive according to claim 1, characterized in that: The thiol is any one of ethanethiol, ethanedithiol, 1-propanethiol, 1,3-propanedithiol and dihydroxypropanethiol; the inhibitor is p-hydroxyanisole, hydroquinone or phenothiazine.

4. A method for preparing a mud-resistant and water-retaining polycarboxylic acid collapse-preventing agent, characterized in that: The following steps are involved: ① Preparing a mixed solution: mixing the anti-mud and water-retaining polycarboxylic acid collapse-preserving agent additive prepared by the method according to any one of claims 1 to 3 with a cross-linking monomer, an unsaturated hydroxy ester, an unsaturated acid, a chain transfer agent and water to obtain a mixed solution; ② Mix the unsaturated polyether and water, stir and disperse them evenly; add the oxidant and ferrous sulfate solution at one time, and after 5 to 20 minutes, add the reducing agent and the mixed solution. After the addition is completed, keep warm for 30 to 60 minutes; ③Adjust the pH to 6-7.

5. The method for preparing the anti-mud and water-retaining polycarboxylic acid collapse-preventing agent according to claim 4, characterized in that: The mass ratio of the collapse retaining agent additive, the cross-linking monomer, the unsaturated hydroxy ester, the unsaturated acid and the chain transfer agent in the mixed solution is 20-25:3-5:8-10:6:1-3.

6. The method for preparing the anti-mud and water-retaining polycarboxylic acid collapse-preventing agent according to claim 4 or 5, characterized in that: In step ②, the amount of the oxidant added is 2% to 15% of the mass of the unsaturated polyether, the amount of the ferrous sulfate solution added is 1% to 3% of the mass of the unsaturated polyether, and the amount of the reducing agent added is 10% to 15% of the mass of the unsaturated polyether.

7. The method for preparing the anti-mud and water-retaining polycarboxylic acid collapse-preventing agent according to claim 6, characterized in that: The mass ratio of the unsaturated polyether to the collapse-preventing agent additive is 1:(0.2-0.25).

8. Anti-mud and water-retaining polycarboxylic acid collapse-preventing agent, characterized in that: The method is prepared by any one of claims 4 to 7.

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