Polycarboxylate water reducer and its compounded anti-mud sacrificial agent

Abstract

The present invention discloses a polycarboxylate water reducer and a compounded anti-mud sacrificial agent thereof. The present invention relates to an organic substance used for compounding a polycarboxylate water reducer finished product, and specifically relates to a polymer substance with a certain polyethylene oxide (PEO) chain length. The technical key point is to select polyethylene glycol, a cyclic monohydric alcohol, and a catalyst to react under certain process conditions to obtain the polycarboxylate water reducer. The sacrificial agent of the present invention can be preferentially adsorbed on clay minerals and produce a steric effect, thereby reducing the amount of clay adsorbed on the polycarboxylate water reducer, thereby significantly improving the anti-mud performance of the polycarboxylate water reducer.

Description

Technical Field

[0001] The invention relates to an organic substance with anti-mud effect, in particular to a polymer substance that can be used for compounding a polycarboxylate water-reducing agent finished product, and further in particular to a polycarboxylate water-reducing agent and a compounded anti-mud sacrificial agent thereof. Background Art

[0002] Polycarboxylate water reducers are widely used in engineering construction due to their excellent performance. When concrete contains clay, polycarboxylate water reducers will have serious problems such as large slump loss over time and reduced water reduction rate, and their performance will be greatly reduced. In recent years, high-quality natural sand and gravel resources have tended to be exhausted, and the mud content of aggregates in concrete is generally high; moreover, the clay components in the sand and gravel pile will penetrate downward with the water, and the clay content in the aggregates will be distributed in a gradient from top to bottom. The mud content in each batch of concrete prepared varies greatly. If the polycarboxylate water reducer has poor anti-mud performance, it will lead to unstable concrete quality. Therefore, for polycarboxylate water reducers, anti-mud methods and technologies have always been the focus of research and attention in the concrete industry.

[0003] At present, there are many academic papers and invention patents involving the anti-mud method of polycarboxylic acid water reducer. For example, Chen Jianguo et al. (Design and performance test of snowflake-shaped anti-mud polycarboxylate water-reducing agent, Journal of Building Materials, 2019) synthesized an anti-mud polycarboxylate water-reducing agent with a snowflake-shaped side chain; Qu Qiheng et al. (Synthesis and performance study of anti-mud and collapse-retaining polycarboxylate water-reducing agent, New Building Materials, 2020) prepared an anti-mud polycarboxylate water-reducing agent using methyl allyl polyoxyethylene ether, acrylic acid, hydroxypropyl ester and phosphate functional monomers; Shao Chengzhi et al. (Preparation and performance study of anti-mud sustained-release polycarboxylate water-reducing agent, New Building Materials, 2021) prepared an anti-mud polycarboxylate water-reducing agent using acrylic acid, hydroxyethyl ester and 2-hydroxyethyl methacrylate phosphate; Xu Feng et al. (Preparation and anti-mud performance study of β-cyclodextrin modified polycarboxylate water-reducing agent, New Building Materials, 2022) introduced β-cyclodextrin into the side chain of polycarboxylate water-reducing agent, and found that the prepared polycarboxylate water-reducing agent had good anti-mud performance.

[0004] The patent "A method for preparing an anti-mud sustained-release polycarboxylate water-reducing agent" (application number 202111506917.5) uses hydroxyethyl acrylate and 2-hydroxyethyl methacrylate phosphate to prepare an anti-mud polycarboxylate water-reducing agent; the patent "A modified cyclodextrin grafted block polycarboxylate water-reducing agent and its preparation method" (application number 202210097749.7) uses a modified cyclodextrin grafted block method to prepare an anti-mud polycarboxylate water-reducing agent; the patent "Anti-mud small material for compounding polycarboxylate water-reducing agent and its use method" (application number 201810390077.2) uses sodium pyrosulfite, sodium hexametaphosphate, sodium tripolyphosphate, sodium nitrate and polycarboxylate water-reducing agent mother liquor for compounding.

[0005] From the anti-mud principle, the adsorption of polycarboxylate water-reducing agent on clay and cement is a competitive relationship. The water-reducing agent molecules adsorbed by clay are ineffective and difficult to play their due role. Since clay is harmful to the adsorption of polycarboxylate water-reducing agent, it is easy to think of a method to reduce its adsorption on clay. The main principle of anti-mud in the above academic papers and invention patents is to reduce the adsorption of polycarboxylate water-reducing agent on clay, so that it can be adsorbed on the surface of cement particles as much as possible.

[0006] In addition, there is another idea for anti-mud, that is, if there is a substance that can be preferentially adsorbed on clay, the adsorption sites on the clay particles will be largely occupied, and the adsorption of polycarboxylate water reducer by clay will be greatly reduced. This substance is the so-called "sacrificial agent". In fact, there are already some academic papers and invention patents involving anti-mud sacrificial agents.

[0007] 1. Academic papers on polycarboxylate water reducer anti-mud sacrificial agent:

[0008] Song Zuobao et al. (Study on the influence of sacrificial agents on the performance of mud-containing mortar, Journal of Wuhan University of Technology, 2015.) studied the influence of sacrificial agents on the fluidity, setting time and mechanical properties of mud-containing mortar; Huang Zhen et al. (Effect of quaternary ammonium salts on the adsorption of polycarboxylate water-reducing agent on the cement-montmorillonite surface, Journal of the Chinese Ceramic Society, 2020.) conducted a systematic study on the mutual influence of quaternary ammonium salt cations of typical structures and the adsorption behavior of polycarboxylate water-reducing agent in the cement-montmorillonite system; Gao Nanxiao et al. (Cationic polymers improve the anti-mud performance of polycarboxylate water-reducing agent and its mechanism of action, Journal of the Chinese Ceramic Society, 2020.) synthesized a series of cationic polymer sacrificial agents by free radical copolymerization of unsaturated quaternary ammonium salt monomers and unsaturated non-(anionic) ionic monomers in aqueous solution; Lv Changyu et al. (Development of a mud-resistant polycarboxylate high-performance water-reducing agent, New Building Materials, 2021.) In the process of compounding the water reducer, a suitable anti-mud sacrificial agent was added to prepare an anti-mud polycarboxylic acid high-performance water reducer; Qiu Tao (The influence of small molecule sacrificial agents on the anti-mud properties of polycarboxylic acid water reducer, master's thesis, 2021.) used polyetheramine D2000, dodecyltrimethylammonium bromide and tetrabutylammonium bromide as anti-mud sacrificial agents, and tested their effects on the dispersion properties of cement-montmorillonite slurry.

[0009] 2. Invention patents related to polycarboxylate water-reducing agent anti-mud sacrificial agent:

[0010] The patent "Anti-mud polycarboxylate water-reducing agent, preparation method and application in concrete" (application number 201710271003.2) prepared a quaternized lignin sulfonate anti-mud sacrificial agent and compounded it with a polycarboxylate water-reducing agent; the patent "Anti-mud sacrificial agent for concrete and preparation method thereof" (application number 201811608157.7) used secondary amines with ethylene oxide and propylene oxide for ring-opening polymerization, and then reacted with a quaternary ammonium salt cationic reagent to obtain a quaternary ammonium salt-terminated anti-mud sacrificial agent; the patent "An adsorption sacrificial agent for polycarboxylate water-reducing agent and preparation method thereof" (application number 201911282183.X) prepared an adsorption sacrificial agent using cationic charged vinyl monomers and amide compounds; the patent "A soil sacrificial agent for polycarboxylate water-reducing agent and preparation method thereof" (application number 202011102803.X ) A soil sacrificial agent was prepared using styrene, acrylic acid, methyl allyl alcohol and ethylene oxide; the patent "A branched anti-mud sacrificial agent and its preparation method" (application number 202111188579.5) used unsaturated acid (anhydride) small monomers and unsaturated quaternary ammonium salt monomers to prepare a branched anti-mud sacrificial agent; the patent "A special anti-mud sacrificial agent for polycarboxylic acid water reducer and its preparation method" (application number 202110215179.2) used acrylamide, acrylic acid, dimethyl diallyl ammonium chloride, dimethylaminoethyl methacrylate, disodium ethylenediaminetetraacetic acid and β-cyclodextrin to prepare an anti-mud sacrificial agent; the patent "An anti-mud sacrificial agent for inhibiting the interlayer adsorption performance of clay minerals and its preparation method" (application number 202210677054.6) used unsaturated polyether monomers, unsaturated quaternary ammonium salt monomers and main chain rigid-flexible modifiers to synthesize an anti-mud sacrificial agent.

[0011] After sorting out and summarizing the above-mentioned academic papers and patents, it is found that the current sacrificial agents have the following main problems: (1) The components of the sacrificial agents reported so far are mainly cationic substances, which are relatively expensive. (2) The effect is unstable, which may affect the water reduction rate and other properties. (3) The compatibility with the polycarboxylate water-reducing agent mother liquor is poor and it is easy to precipitate. Therefore, it is urgent to invent a new sacrificial agent. Summary of the invention

[0012] In view of the current situation that the effect of ordinary polycarboxylate water reducer is seriously reduced when the mud content is high, the present invention proposes a functional substance that can improve the anti-mud performance of polycarboxylate water reducer, specifically a polycarboxylate water reducer and a compounded anti-mud sacrificial agent thereof, to improve the anti-mud performance of polycarboxylate water reducer.

[0013] On the one hand, the anti-mud sacrificial agent of the present invention can be preferentially adsorbed on clay minerals, and on the other hand, the large cyclic group at the end of the sacrificial agent molecule increases its steric hindrance effect. The dual effects reduce the adsorption amount of clay on the polycarboxylate water-reducing agent, significantly reduce the sensitivity of the polycarboxylate water-reducing agent to clay minerals, thereby ensuring the transportation and pouring of concrete.

[0014] The anti-mud sacrificial agent is prepared by a two-step reaction: first, a polyether compound with a certain PEO chain length is prepared from polyethylene glycol (PEG200, PEG400 or PEG600), and then the polyether compound is further etherified and capped with a monohydric alcohol (cycloheptanol or cyclooctanol or cyclodecanol). The reaction for synthesizing the anti-mud sacrificial agent belongs to a polycondensation reaction. First, PEG is etherified, and the etherified PEG intermediate has a hydroxyl group at both ends, which is capped with a cyclic monohydric alcohol. The main purpose is: (1) to eliminate the effect of hydroxyl groups on cement hydration. (2) The anti-mud sacrificial agent has a large cyclic group at both ends. In this way, the PEO side chain length and steric hindrance effect of the anti-mud sacrificial agent molecule generated are increased.

[0015] When in use, the anti-mud sacrificial agent is compounded with a polycarboxylate water-reducing agent mother solution, water and other substances (such as a retarder, an air entraining agent or an antifreeze component) to obtain a polycarboxylate water-reducing agent finished product.

[0016] To achieve the above invention objectives, the technical solution is as follows:

[0017] The anti-mud sacrificial agent for compounding polycarboxylate water reducer is obtained according to the following preparation method, and the preparation method comprises the following steps:

[0018] 1) Stir the polyethylene glycol until it is uniform and heat the temperature to 50~60℃;

[0019] 2) Add 2 / 3~4 / 5 of the total amount of catalyst and stir for 5~10 minutes;

[0020] 3) Then raise the temperature to 120~200 o C, insulation time 1~7 hours;

[0021] 4) Then cool to 40 o Below C;

[0022] 5) adding a cyclic monohydric alcohol and the remaining amount of the catalyst;

[0023] 6) Raise the temperature to 110~170℃ and keep warm for 1~8 hours;

[0024] 7) Then cool down to room temperature to obtain the anti-mud sacrificial agent for compounding polycarboxylate water reducer;

[0025] Wherein, in step 1), the polyethylene glycol is a mixture of one or more of PEG200, PEG400 or PEG600;

[0026] In step 2), the catalyst is a mixture of one or more of concentrated sulfuric acid, p-toluenesulfonic acid or a strongly acidic ion exchange resin;

[0027] In step 5), the cyclic monohydric alcohol is a mixture of one or more of cycloheptanol, cyclooctanol or cyclodecanol;

[0028] In addition, the weight ratio of the polyethylene glycol, cyclic alcohol and catalyst added in steps 1) to 5) is (600-900): (100-400): (5-40).

[0029] Preferably, the weight ratio of the polyethylene glycol, the cyclic monohydric alcohol and the catalyst is (700-900): (100-300): (20-35).

[0030] A polycarboxylate water-reducing agent comprises a polycarboxylate water-reducing agent mother liquor and the above-mentioned anti-mud sacrificial agent, wherein the addition amount of the above-mentioned anti-mud sacrificial agent is 5-50‰ (weight) of the polycarboxylate water-reducing agent.

[0031] The anti-mud sacrificial agent is used for compounding during the production of polycarboxylate water reducer. The obtained polycarboxylate water reducer containing the anti-mud sacrificial agent is added to concrete, which can reduce the adsorption of clay on the polycarboxylate water reducer and significantly reduce the sensitivity of the polycarboxylate water reducer to clay minerals, thereby ensuring the transportation and pouring of concrete.

[0032] When used, the anti-mud sacrificial agent obtained by the present invention is added in an amount of 5-50‰ (weight) of the finished polycarboxylate water reducer. The anti-mud sacrificial agent for polycarboxylate water reducer prepared by the present invention is compounded with the polycarboxylate water reducer mother liquor and water to effectively improve the anti-mud performance of the polycarboxylate water reducer.

[0033] The technical principle of the present invention is:

[0034] Since the main raw materials for producing polycarboxylic acid water-reducing agent mother liquor are polyether macromonomer and acrylic acid, the polyether macromonomer will introduce PEO side chain; at the same time, the clay interlayer contains a large number of silanol groups, which are easy to form hydrogen bonds with the oxygen atoms in the PEO side chain of the polyether macromonomer. The PEO side chain can easily enter the clay mineral interlayer (i.e., intercalation adsorption), thereby causing the adsorbed part of the water-reducing agent molecules to fail.

[0035] Compared with the prior art, the cationic groups are preferentially adsorbed on the negatively charged clay surface, thereby reducing the adsorption of clay to polycarboxylate water reducer, that is, they mainly rely on the charge effect. Different from this, the idea of ​​the present invention is that since the PEO side chain on the polycarboxylate water reducer molecule is easily adsorbed between clay layers, a sacrificial agent is invented, which is precisely to allow it to carry PEO, and the PEO with a higher degree of polymerization is preferentially adsorbed with clay, and at the same time, the sacrificial agent molecule is designed to have a large cyclic group at the end, so as to appropriately increase its steric hindrance effect. The molecular weight of the polyether macromonomer currently available on the market is generally 2400~3000 g / mol, and the degree of polymerization of PEO is only 53~67. Although its comprehensive performance such as water reduction rate and slump retention performance is good, its anti-mud performance is poor; and for the majority of polycarboxylate water reducer synthesis manufacturers, the polyether macromonomer raw materials are purchased from related enterprises, and their PEO length is fixed, which cannot be adjusted by water reducer manufacturers. The present invention controls the PEO polymerization degree and performs reasonable end-capping, controls the PEO polymerization degree of the sacrificial agent to 100-300, and has a significant anti-mud effect. When the sacrificial agent of the present invention encounters clay minerals, its PEO long side chain will be embedded in the clay interlayer to occupy the adsorption site, and its strong steric hindrance effect will hinder the polycarboxylate water-reducing agent molecules from entering the clay interlayer, thereby reducing the adsorption amount of the polycarboxylate water-reducing agent on the clay through the dual effects of preferential adsorption and steric hindrance formed by the molecular structure, reducing the intercalation adsorption, and playing the role of a "sacrificial agent".

[0036] After consulting relevant literature and patents, no data was found that clearly proposed the anti-mud sacrificial agent, so the present invention has outstanding substantial characteristics and significant progress.

[0037] Compared with the prior art, the present invention has obvious innovation and remarkable effects: (1) The anti-mud active ingredients and anti-mud principle are significantly different. (2) The anti-mud effect is relatively significant. (3) The process is different. The anti-mud sacrificial agent is prepared by a two-step etherification reaction. (4) The production cost of the present invention is relatively low. (5) Compared with other sacrificial agents, the sacrificial agent of the present invention has good compatibility with the mother liquor of polycarboxylic acid water reducer.

[0038] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the specific implementation methods of the present application, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0040] Figure 1Effect of anti-mud sacrificial agent on the rheological properties (shear stress) of montmorillonite-containing cement mortar.

[0041] Figure 2 Effect of anti-mud sacrificial agent on the rheological properties (viscosity) of cement mortar containing montmorillonite.

[0042] Figure 3 The effect of anti-mud sacrificial agent on the slump loss of concrete over time. DETAILED DESCRIPTION

[0043] The present invention will be described in more detail below with reference to the accompanying drawings, in which preferred embodiments of the present invention are shown. It should be understood that those skilled in the art can modify the present invention described herein and still achieve the beneficial effects of the present invention. In practical applications, the anti-mud sacrificial agent itself has anti-mud properties and can be directly added to the polycarboxylate water-reducing agent mother liquor and mixed evenly. Therefore, the specific implementation method can be mainly divided into two steps. The first step is to synthesize the anti-mud sacrificial agent, and the second step is to compound the anti-mud sacrificial agent with the polycarboxylate water-reducing agent mother liquor.

[0044] 1. Synthesis of anti-mud sacrificial agent

[0045] Example 1: Synthesis of Anti-mud Sacrificial Agent 1

[0046] 1) Add 700 g of PEG200 into a three-necked flask, start stirring, and heat to 50°C;

[0047] 2) Add 7 g p-toluenesulfonic acid and 8 g concentrated sulfuric acid and stir for 5 minutes;

[0048] 3) Then heat up to 120 o C, insulation time 1.5 hours;

[0049] 4) Then cool to 40 o Below C;

[0050] 5) Add 300 g of cycloheptanol, 2.5 g of p-toluenesulfonic acid and 2.5 g of concentrated sulfuric acid;

[0051] 6) Heat to 130°C and keep warm for 2 hours;

[0052] 7) Then cool down to room temperature to obtain the anti-mud sacrificial agent 1.

[0053] Example 2: Synthesis of Anti-mud Sacrificial Agent 2

[0054] 1) Add 800 g of PEG400 into a three-necked flask, start stirring, and heat to 60°C;

[0055] 2) Add 19 g of concentrated sulfuric acid and stir for 10 minutes;

[0056] 3) Then heat up to 135o C, insulation time 3 hours;

[0057] 4) Then cool to 40 o Below C;

[0058] 5) Add 200 g of cyclooctanol and 6 g of concentrated sulfuric acid;

[0059] 6) Heat to 150°C and keep warm for 4 hours;

[0060] 7) Then cool down to room temperature to obtain the anti-mud sacrificial agent 2.

[0061] Example 3: Synthesis of Anti-mud Sacrificial Agent 3

[0062] 1) Add 400 g PEG400 and 500 g PEG600 into a three-necked flask, start stirring, and heat to 60°C;

[0063] 2) Add 28 grams of concentrated sulfuric acid and stir for 10 minutes;

[0064] 3) Then heat up to 150 o C, insulation time 6 hours;

[0065] 4) Then cool to 40 o Below C;

[0066] 5) Add 50 g of cyclooctanol, 50 g of cyclodecyl alcohol and 7 g of concentrated sulfuric acid;

[0067] 6) Raise the temperature to 170°C and keep warm for 5 hours;

[0068] 7) Then cool down to room temperature to obtain the anti-mud sacrificial agent 3.

[0069] , Compounding of anti-mud sacrificial agent and polycarboxylate water-reducing agent mother liquor

[0070] (1) Synthesis method of polycarboxylate water-reducing agent mother liquor

[0071] Calculated for synthesizing 1000g polycarboxylic acid water-reducing agent mother liquor. First, add 360g methyl allyl polyoxyethylene ether (i.e. HPEG, number average molecular weight is 2400g / mol) and 350g distilled water into a three-necked flask and stir at room temperature for 10 minutes to obtain the base material. Prepare the drop solution, the composition of liquid A is: 1.4g mercaptopropionic acid, 0.6g vitamin C and 80g distilled water, and the composition of liquid B is: 40g acrylic acid and 45g distilled water. Add 4g hydrogen peroxide solution to the base material and stir for 5 min. Then, use a peristaltic pump to control the dropping time of liquid A and liquid B to 3h and 2.5h respectively. Finally, add 119g of water after 1h of dripping, and neutralize with 30% NaOH solution to a pH value of about 7 to obtain the polycarboxylic acid water-reducing agent mother liquor.

[0072] (2) Compounding ratio

[0073] Four polycarboxylate water-reducing agent products were obtained by compounding according to the weight ratio, as shown in Table 1 (based on 1000 grams). Among them, SP1, SP2, and SP3 were added with 10‰ of anti-mud sacrificial agent 1, anti-mud sacrificial agent 2, and anti-mud sacrificial agent 3 respectively; SP0 was used as a blank sample to compare the effect after the anti-mud sacrificial agent was added; and in order to make the test results more comparable, the sum of the anti-mud sacrificial agent and the polycarboxylate water-reducing agent mother liquor was 220 grams.

[0074] Table 1 Proportions of finished polycarboxylate water-reducing agent (unit: g)

[0075]

[0076] Verification test

[0077] (1) Test results of sacrificial agent PEO chain length

[0078] The number average molecular weights of the anti-mud sacrificial agent 1, anti-mud sacrificial agent 2 and anti-mud sacrificial agent 3 measured by gel permeation chromatography (GPC) were 6710 g / mol, 8930 g / mol and 11400 g / mol, respectively. Based on this, their PEO polymerization degrees can be calculated by subtracting the terminal molecular weight from the number average molecular weight and then dividing it by the molecular weight of the PEO unit (i.e., 44 g / mol). After calculation, it can be obtained that the PEO polymerization degrees of the anti-mud sacrificial agent 1, anti-mud sacrificial agent 2 and anti-mud sacrificial agent 3 are approximately 147, 197 and 252, respectively, which are much higher than the PEO polymerization degree of the polyether macromonomer (53-67).

[0079] (2) Effect of anti-mud sacrificial agent on the rheological properties of montmorillonite-containing cement mortar

[0080] It is well known to those skilled in the art that the adsorption capacity of montmorillonite on polycarboxylate water reducer is about ten times higher than that of other clay minerals such as kaolin or illite, and a small amount of montmorillonite can greatly weaken the dispersibility of water reducer. Adding 1% to 2% of montmorillonite by weight of cement is sufficient to test the clay resistance of polycarboxylate water reducer, and the test adopts a ratio of 2%.

[0081] Cement mortar was prepared according to GB / T17671-2021 "Test Method for Strength of Cement Mortar (ISO Method)", with the proportions of 118.5 g standard sand, 100 g 42.5R ordinary Portland cement, 2 g montmorillonite, 40 g water, and 2 g of the finished polycarboxylate water reducer (see Table 1 for the proportion). The shear stress and viscosity of the mortar were measured using a NXS-11B rotary viscometer.

[0082] The results are as follows Figure 1 , 2As shown, as the shear rate increases, the shear stress gradually increases, while the viscosity gradually decreases; at the same shear rate, the shear stress and viscosity of the mortar containing the sacrificial agent are reduced, especially the effect of SP3 is the most significant, indicating that the sacrificial agent of the present invention significantly improves the anti-mud ability of the polycarboxylate water-reducing agent.

[0083] (3) Effect of anti-mud sacrificial agent on the slump loss of concrete over time

[0084] The effect of sacrificial agent can be well characterized by testing the slump loss of mud concrete over time.

[0085] The river sand comes from Yuniao River in Yantai City, Shandong Province, with a fineness modulus of 2.7. According to GB / T14684-2011 "Construction Sand", the mud content of the river sand is measured to be 5.2%.

[0086] To prepare C30 concrete, the mix ratio is: 2.3kg 42.5R ordinary Portland cement, 0.8kg ground slag, 0.7kg fly ash, 9.1kg river sand, 9.9kg gravel, 1.75kg water, and 76g water reducer.

[0087] The type of water reducing agent was changed (see Table 1), and the slump of concrete was measured in the initial state and after 1 hour.

[0088] Figure 3 The results show that in the initial state, SP3 has the highest slump, followed by SP1 and SP2, and SP0 is the worst. After 1 hour, the slumps of SP1, SP2 and SP3 are significantly higher than SP0, among which SP3 has the highest slump. From the perspective of time loss, the time loss of SP0, SP1, SP2 and SP3 are 30mm, 45mm, 60mm and 90mm respectively, among which SP3 is the best.

[0089] Verification tests show that the anti-mud sacrificial agent of the present invention significantly reduces the sensitivity of the polycarboxylate water-reducing agent to clay and greatly improves the anti-mud performance of the polycarboxylate water-reducing agent.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Anti-mud sacrificial agent for compounding polycarboxylate water reducer, characterized in that The anti-mud sacrificial agent is obtained according to the following preparation method, which comprises the following steps: Step 1) Stir the polyethylene glycol until it is uniform and heat it to 50-60°C; Step 2) Add 2 / 3~4 / 5 of the total amount of catalyst and stir for 5~10 minutes; Step 3) Then raise the temperature to 120~200 o C, insulation time 1~7 hours; Step 4) Then cool to 40 o Below C; Step 5) adding a cyclic monohydric alcohol and the remaining amount of the catalyst; Step 6) heating to 110-170°C for 1-8 hours; Step 7) Then cool down to room temperature to obtain the anti-mud sacrificial agent; Wherein, in step 1), the polyethylene glycol is a mixture of one or more of PEG200, PEG400 or PEG600; In step 2), the catalyst is a mixture of one or more of concentrated sulfuric acid, p-toluenesulfonic acid or a strongly acidic ion exchange resin; In step 5), the cyclic monohydric alcohol is a mixture of one or more of cycloheptanol, cyclooctanol or cyclodecanol; In addition, the weight ratio of the polyethylene glycol, cyclic monohydric alcohol and catalyst added in step 1) to step 5) is 600-900:100-400:5-40.

2. The anti-mud sacrificial agent for compounding polycarboxylate water reducer according to claim 1, characterized in that The weight ratio of the polyethylene glycol, the cyclic monohydric alcohol and the catalyst is 600-900:100-400:5-40.

3. A polycarboxylate water reducer, characterized in that It comprises a polycarboxylate water-reducing agent mother solution and the anti-mud sacrificial agent of claim 1, Wherein, the addition amount of the anti-mud sacrificial agent of claim 1 is 5-50‰ (weight) of the polycarboxylate water reducer.

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