Preparation and application of low-air-entraining TPEG polyether macromonomer

Abstract

The invention relates to the technical field of polycarboxylic acid water reducer macromonomers, in particular to preparation and application of a low-air-entraining type TPEG polyether macromonomer, and the low-air-entraining type TPEG polyether macromonomer mainly comprises the following components in parts by mass: 10-20 parts of organopolysiloxane, 1-5 parts of an emulsifier, 2-10 parts of a thickener and 60-80 parts of a solvent. The emulsifier is one or a combination of more of sorbitan monostearate, sodium lauryl sulfate, polyoxyethylene ether, polyvinyl alcohol and sorbitan monooleate; the thickening agent is one or a combination of several of carboxymethyl cellulose, sodium polyacrylate, tragacanth, sodium starch phosphate, hydroxypropyl methyl cellulose and sodium alginate; wherein the solvent is water, and the low-air-entraining type TPEG polyether macromonomer disclosed by the invention has the following beneficial effects that the low-air-entraining type TPEG polyether macromonomer researched by the invention is small in adding amount of a defoaming agent, stable, efficient, high in economic benefit, easy to meter and simple and convenient to operate; redundant large bubbles in the concrete can be eliminated, proper small bubbles are reserved, the strength of the concrete is enhanced, and the surface of the concrete is more attractive.

Description

Technical Field

[0001] The invention relates to the technical field of polycarboxylate water-reducing agent macromonomers, and in particular to the preparation and application of a low-air entraining TPEG polyether macromonomer. Background Art

[0002] Polycarboxylate water reducer has good dispersibility, can reduce concrete collapse, and has high plasticizing effect and good fluidity at low dosage. It has obvious reinforcement effect on concrete, can reduce concrete shrinkage, and endows concrete with excellent construction and workability and excellent durability. With the continuous acceleration of my country's urbanization process and the continuous development of large-scale infrastructure, polycarboxylate water reducer is widely used in high-speed railways, bridges, highways, etc. due to its special molecular structure. With the increase in demand for concrete, performance requirements are becoming more and more diversified. In order to meet the requirements of high-performance concrete, the development of high-performance water reducers and water reducer macromonomers is imminent.

[0003] TPEG is a prenol polyoxyethylene ether, as a special polyether for polycarboxylate water-reducing agent, it is widely used because of its efficient water-reducing performance and economic rationality. Since the introduction of prenol polyoxyethylene ether, it has good market adaptability and its market share has increased year by year. However, with the development of the concrete industry, prenol polyoxyethylene ether type water-reducing agent has the problem of more foams in the application process, which easily causes the concrete air content to be high, is not conducive to the collapse protection, and also causes the decline of concrete strength. Therefore, to solve the above problems, those skilled in the art are committed to developing a kind of TPEG polyether macromonomer, by reducing the foam of polycarboxylate water-reducing agent, thereby obtaining a very stable low air entraining type polycarboxylate water-reducing agent for storage, and solving the problem that the air entraining property of polycarboxylate water-reducing agent is too large to cause the concrete air content to be high and the hardening strength to be low. Summary of the invention

[0004] The purpose of the present invention is to provide an emulsion defoamer for preparing a TPEG macromonomer, which can reduce the foam of a polycarboxylate water-reducing agent.

[0005] The above technical objectives of the present invention are achieved through the following technical solutions:

[0006] An emulsion defoamer, the main components of which are: 10-20 parts of organopolysiloxane, 1-5 parts of emulsifier, 2-10 parts of thickener, and 60-80 parts of solvent;

[0007] The emulsifier is one or a combination of sorbitan monostearate, sodium lauryl sulfate, polyoxyethylene ether, polyvinyl alcohol, and sorbitan monooleate;

[0008] The thickener is one or a combination of carboxymethyl cellulose, sodium polyacrylate, tragacanth gum, sodium starch phosphate, hydroxypropyl methylcellulose, and sodium alginate;

[0009] Wherein, the solvent is water.

[0010] Another object of the present invention is to provide a low-air entraining TPEG polyether macromonomer, which can reduce the foam of the polycarboxylate water reducer, thereby obtaining a low-air entraining polycarboxylate water reducer with stable storage.

[0011] The above technical objectives of the present invention are achieved through the following technical solutions:

[0012] A low-air entraining TPEG polyether macromonomer, characterized in that it comprises the emulsion defoamer according to claim 1, wherein the proportion of the emulsion defoamer in the TPEG polyether macromonomer is 8.5 to 20 ppm:1.

[0013] Preferably, the proportion of the emulsion defoamer in the TPEG polyether macromonomer is preferably 8.5 ppm.

[0014] The third object of the present invention is to provide a method for preparing the above-mentioned low-air entraining TPEG polyether macromonomer, comprising: weighing an organic polysiloxane, an emulsifier, a thickener and a solvent according to a certain weight and mixing them evenly to obtain a uniform emulsion-type defoamer, and then adding the prepared emulsion-type defoamer to the liquid TPEG polyether macromonomer according to the addition ratio.

[0015] The proportion of the emulsion defoamer in the TPEG polyether macromonomer is 8.5 to 20 ppm:1.

[0016] Preferably, the proportion of the emulsion defoamer in the TPEG polyether macromonomer is preferably 8.5 ppm.

[0017] Preferably, the mixing time of the emulsion defoamer and the TPEG polyether macromonomer is 30 to 60 minutes.

[0018] The above time is determined by the uniformity of material mixing and production efficiency. Too short a time may lead to uneven mixing, while too long a time may increase energy consumption. Appropriate mixing time can achieve uniform mixing while minimizing production cycle and improving production capacity.

[0019] Preferably, the emulsion defoamer is added at a temperature of 85°C to 100°C.

[0020] The above temperature is determined according to the material characteristics. At low temperatures, TPEG products tend to coagulate, which is not conducive to the full mixing of the defoamer and the macromonomer, affecting stability. At high temperatures, the defoamer tends to demulsify, resulting in reduced performance and affecting the use effect.

[0021] Preferably, the addition temperature of the emulsion defoamer is 85°C.

[0022] The present invention also provides an application method of the low air entraining TPEG polyether macromonomer. The polycarboxylate water reducer obtained by the application solves the problem of high air content and low hardening strength of concrete caused by excessive air entrainment of the polycarboxylate water reducer.

[0023] The above technical objectives of the present invention are achieved through the following technical solutions:

[0024] The invention discloses an application of a low-air entraining TPEG polyether macromonomer, and uses the low-air entraining TPEG polyether macromonomer to carry out polymerization reaction to prepare a polycarboxylic acid water reducer.

[0025] In summary, the present invention has the following beneficial effects:

[0026] 1. The low-air entrainment TPEG polyether macromonomer studied in the present invention has a small amount of defoamer added, is stable and efficient, has high economic benefits, is easy to measure and simple to operate;

[0027] 2. Since the polycarboxylate water-reducing agent itself contains a large amount of air, resulting in the phenomenon of many bubbles on the surface of the concrete, the low-air-entraining polycarboxylate water-reducing agent synthesized by the polyether monomer with the introduction of the defoaming agent retains the appropriate air-entraining property, which can eliminate the excess large bubbles in the concrete, retain the appropriate small bubbles, enhance the strength of the concrete and make the surface of the concrete more beautiful;

[0028] 3. In addition to improving the pore structure and density of concrete, the introduction of defoamers can also better control the problems of concrete slow setting and water seepage, and has become an indispensable component in the concrete mix ratio;

[0029] 4. Compared with the prior art, the low-air entraining TPEG polyether macromonomer provided by the present invention has a high water-reducing effect while also having the functions of defoaming and foam suppression. It has strong defoaming ability and good stability, and effectively avoids the problem of poor compatibility and poor placement stability caused by the compounding of polycarboxylic acid water-reducing agent and defoaming agent, resulting in poor control of air content. DETAILED DESCRIPTION

[0030] The present invention is described in further detail below.

[0031] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

[0032] Embodiment 1:

[0033] 1) Add isopentanol and sodium metal to a reactor to react and prepare a chain initiator. After the preparation is completed, the reactor is purged with nitrogen. After nitrogen replacement, ethylene oxide is continuously introduced to carry out anionic polymerization reaction, and the pressure of the reactor is controlled to be 150kPa-350kPa, and the temperature of the reactor is stabilized at 100-120°C. After the addition of ethylene oxide is completed, the reaction is considered to be completed after aging until the pressure no longer decreases. After the reaction is completed, the reactor is cooled and discharged to obtain an isopentanol polyoxyethylene ether oligomer with a molecular weight of 500.

[0034] 2) Add ethylene oxide to the isopentanol polyoxyethylene ether oligomer obtained in step 1 again to carry out anionic polymerization reaction, control the pressure of the reactor to 150kPa-450kPa, effectively control the temperature of the reactor to be stable at 110-130°C, and ripen until the pressure no longer decreases after the addition of ethylene oxide. After the reaction is completed, cool the reactor and add acid to carry out neutralization reaction, neutralize until the product pH is 6-8, and obtain an isopentanol polyoxyethylene ether product with a molecular weight of 2400. Direct slicing without adding a defoamer is used as a control case, and a blank control is performed.

[0035] Embodiment 2:

[0036] 1) Add isopentanol and sodium metal to a reactor to react and prepare a chain initiator. After the preparation is completed, the reactor is purged with nitrogen. After nitrogen replacement, ethylene oxide is continuously introduced to carry out anionic polymerization reaction, and the pressure of the reactor is controlled to be 150kPa-350kPa, and the temperature of the reactor is stabilized at 100-120°C. After the addition of ethylene oxide is completed, the reaction is considered to be completed after aging until the pressure no longer decreases. After the reaction is completed, the reactor is cooled and discharged to obtain an isopentanol polyoxyethylene ether oligomer with a molecular weight of 500.

[0037] 2) Adding ethylene oxide to the isopentanol polyoxyethylene ether oligomer obtained in step 1 again for anionic polymerization, controlling the pressure of the reactor to 150kPa-450kPa, effectively controlling the temperature of the reactor to be stable at 110-130°C, and aging until the pressure no longer decreases after the addition of ethylene oxide is completed, and the reaction is considered to be complete. After the reaction is completed, the reactor is cooled and acid is added for neutralization reaction, and the product pH is neutralized to 6-8 to obtain an isopentanol polyoxyethylene ether product with a molecular weight of 2400.

[0038] 3) Weigh 10 parts of organosiloxane, 5 parts of polyoxyethylene ether, 3 parts of hydroxypropyl methylcellulose, and 80 parts of solvent, and mix them evenly until a uniform emulsion is obtained to obtain a defoamer. Add the above-measured 8.5ppm defoamer to the isopentanol polyoxyethylene ether product obtained in step 2, control the addition temperature to 85°C, mix in the reactor for 30 minutes after the addition is completed, unload and slice after the mixing is completed, and obtain a low-air entrainment TPEG polyether macromonomer.

[0039] Embodiment 3:

[0040] 1) Add isopentanol and sodium metal to a reactor to react and prepare a chain initiator. After the preparation is completed, the reactor is purged with nitrogen. After nitrogen replacement, ethylene oxide is continuously introduced to carry out anionic polymerization reaction, and the pressure of the reactor is controlled to be 150kPa-350kPa, and the temperature of the reactor is stabilized at 100-120°C. After the addition of ethylene oxide is completed, the reaction is considered to be completed after aging until the pressure no longer decreases. After the reaction is completed, the reactor is cooled and discharged to obtain an isopentanol polyoxyethylene ether oligomer with a molecular weight of 500.

[0041] 2) Adding ethylene oxide to the isopentanol polyoxyethylene ether oligomer obtained in step 1 again for anionic polymerization, controlling the pressure of the reactor to 150kPa-450kPa, effectively controlling the temperature of the reactor to be stable at 110-130°C, and aging until the pressure no longer decreases after the addition of ethylene oxide is completed, and the reaction is considered to be complete. After the reaction is completed, the reactor is cooled and acid is added for neutralization reaction, and the product pH is neutralized to 6-8 to obtain an isopentanol polyoxyethylene ether product with a molecular weight of 2400.

[0042] 3) Weigh 10 parts of organosiloxane, 1 part of sorbitan monostearate, 2 parts of carboxymethyl cellulose, and 60 parts of solvent, and mix them evenly until a uniform emulsion is obtained to obtain a defoamer. Add the above-measured 14 ppm defoamer to the isopentanol polyoxyethylene ether product obtained in step 2, control the addition temperature to 85° C., mix in the reactor for 45 minutes after the addition is completed, unload and slice after the mixing is completed, and obtain a low-air entrainment TPEG polyether macromonomer.

[0043] Embodiment 4:

[0044] 1) Add isopentanol and sodium metal to a reactor to react and prepare a chain initiator. After the preparation is completed, the reactor is purged with nitrogen. After nitrogen replacement, ethylene oxide is continuously introduced to carry out anionic polymerization reaction, and the pressure of the reactor is controlled to be 150kPa-350kPa, and the temperature of the reactor is stabilized at 100-120°C. After the addition of ethylene oxide is completed, the reaction is considered to be completed after aging until the pressure no longer decreases. After the reaction is completed, the reactor is cooled and discharged to obtain an isopentanol polyoxyethylene ether oligomer with a molecular weight of 500.

[0045] 2) Adding ethylene oxide to the isopentanol polyoxyethylene ether oligomer obtained in step 1 again for anionic polymerization, controlling the pressure of the reactor to 150kPa-450kPa, effectively controlling the temperature of the reactor to be stable at 110-130°C, and aging until the pressure no longer decreases after the addition of ethylene oxide is completed, and the reaction is considered to be complete. After the reaction is completed, the reactor is cooled and acid is added for neutralization reaction, and the product pH is neutralized to 6-8 to obtain an isopentanol polyoxyethylene ether product with a molecular weight of 2400.

[0046] 3) Weigh 15 parts of organosiloxane, 3 parts of sodium lauryl sulfate, 6 parts of sodium polyacrylate, and 70 parts of solvent, and mix them evenly until a uniform emulsion is obtained to obtain a defoamer. Add the above-measured 20ppm of defoamer to the isopentanol polyoxyethylene ether product obtained in step 2, control the addition temperature to 90°C, mix in the reactor for 45 minutes after the addition is completed, unload and slice after the mixing is completed, and obtain a low-air entrainment TPEG polyether macromonomer.

[0047] Embodiment 5:

[0048] 1) Add isopentanol and sodium metal to a reactor to react and prepare a chain initiator. After the preparation is completed, the reactor is purged with nitrogen. After nitrogen replacement, ethylene oxide is continuously introduced to carry out anionic polymerization reaction, and the pressure of the reactor is controlled to be 150kPa-350kPa, and the temperature of the reactor is stabilized at 100-120°C. After the addition of ethylene oxide is completed, the reaction is considered to be completed after aging until the pressure no longer decreases. After the reaction is completed, the reactor is cooled and discharged to obtain an isopentanol polyoxyethylene ether oligomer with a molecular weight of 500.

[0049] 2) Adding ethylene oxide to the isopentanol polyoxyethylene ether oligomer obtained in step 1 again for anionic polymerization, controlling the pressure of the reactor to 150kPa-450kPa, effectively controlling the temperature of the reactor to be stable at 110-130°C, and aging until the pressure no longer decreases after the addition of ethylene oxide is completed, and the reaction is considered to be complete. After the reaction is completed, the reactor is cooled and acid is added for neutralization reaction, and the product pH is neutralized to 6-8 to obtain an isopentanol polyoxyethylene ether product with a molecular weight of 2400.

[0050] 3) Weigh 20 parts of organosiloxane, 4 parts of polyoxyethylene ether, 8 parts of tragacanth gum, and 80 parts of solvent, and mix them evenly until a uniform emulsion is obtained to obtain a defoamer. Add the above-measured 8.5ppm defoamer to the isopentanol polyoxyethylene ether product obtained in step 2, control the addition temperature to 90°C, mix in the reactor for 45 minutes after the addition is completed, unload and slice after the mixing is completed, and obtain a low-air entrainment TPEG polyether macromonomer.

[0051] Embodiment 6:

[0052] 1) Add isopentanol and sodium metal to a reactor to react and prepare a chain initiator. After the preparation is completed, the reactor is purged with nitrogen. After nitrogen replacement, ethylene oxide is continuously introduced to carry out anionic polymerization reaction, and the pressure of the reactor is controlled to be 150kPa-350kPa, and the temperature of the reactor is stabilized at 100-120°C. After the addition of ethylene oxide is completed, the reaction is considered to be completed after aging until the pressure no longer decreases. After the reaction is completed, the reactor is cooled and discharged to obtain an isopentanol polyoxyethylene ether oligomer with a molecular weight of 500.

[0053] 2) Adding ethylene oxide to the isopentanol polyoxyethylene ether oligomer obtained in step 1 again for anionic polymerization, controlling the pressure of the reactor to 150kPa-450kPa, effectively controlling the temperature of the reactor to be stable at 110-130°C, and aging until the pressure no longer decreases after the addition of ethylene oxide is completed, and the reaction is considered to be complete. After the reaction is completed, the reactor is cooled and acid is added for neutralization reaction, and the product pH is neutralized to 6-8 to obtain an isopentanol polyoxyethylene ether product with a molecular weight of 2400.

[0054] 3) Weigh 20 parts of organosiloxane, 5 parts of polyvinyl alcohol, 10 parts of sodium starch phosphate, and 80 parts of solvent, and mix them evenly until a uniform emulsion is obtained to obtain a defoamer. Add the above-measured 14ppm defoamer to the isopentanol polyoxyethylene ether product obtained in step 2, control the addition temperature to 100°C, mix in the reactor for 45 minutes after the addition is completed, unload and slice after the mixing is completed, and obtain a low-entraining TPEG polyether macromonomer.

[0055] Embodiment 7:

[0056] 1) Add isopentanol and sodium metal to a reactor to react and prepare a chain initiator. After the preparation is completed, the reactor is purged with nitrogen. After nitrogen replacement, ethylene oxide is continuously introduced to carry out anionic polymerization reaction, and the pressure of the reactor is controlled to be 150kPa-350kPa, and the temperature of the reactor is stabilized at 100-120°C. After the addition of ethylene oxide is completed, the reaction is considered to be completed after aging until the pressure no longer decreases. After the reaction is completed, the reactor is cooled and discharged to obtain an isopentanol polyoxyethylene ether oligomer with a molecular weight of 500.

[0057] 2) Adding ethylene oxide to the isopentanol polyoxyethylene ether oligomer obtained in step 1 again for anionic polymerization, controlling the pressure of the reactor to 150kPa-450kPa, effectively controlling the temperature of the reactor to be stable at 110-130°C, and aging until the pressure no longer decreases after the addition of ethylene oxide is completed, and the reaction is considered to be complete. After the reaction is completed, the reactor is cooled and acid is added for neutralization reaction, and the product pH is neutralized to 6-8 to obtain an isopentanol polyoxyethylene ether product with a molecular weight of 2400.

[0058] 3) Weigh 10 parts of organosiloxane, 5 parts of sorbitan monooleate, 3 parts of sodium alginate, and 80 parts of solvent, and mix them evenly until a uniform emulsion is obtained to obtain a defoamer. Add the above-measured 20ppm defoamer to the isopentanol polyoxyethylene ether product obtained in step 2, control the addition temperature to 100°C, mix in the reactor for 60 minutes after the addition is completed, unload and slice after the mixing is completed, and obtain a low-entraining TPEG polyether macromonomer.

[0059] The present invention verifies the performance of the polyether monomer by conducting a pure slurry flowability test, combining a concrete strength test, and conducting relevant product index tests.

[0060] The cement paste fluidity test is carried out according to GB / TS077-2000 "Concrete admixture homogeneity test method", accurately weighing 300g of cement and fixing the water-cement ratio. The cement paste fluidity is measured as a parameter to characterize its performance.

[0061] The concrete strength test is carried out in accordance with GB / T50081-2002 "Standard for Test Methods of Mechanical Properties of Ordinary Concrete" to determine the compressive strength.

[0062] The air content test is carried out in accordance with GBT50080.2002 "Standard for Test Methods for Performance of Ordinary Concrete Mixtures".

[0063] According to the methods and steps of Examples 2-7 and the operating parameters of Table 1, low-air entraining TPEG polyether macromonomers were prepared.

[0064] Table 1 Defoamer addition control parameters

[0065] Operation parameters Adding temperature / ℃ Defoamer addition amount / ppm Mixing time / min Example 1 - 0 - Example 2 85 8.5 30 Example 3 85 14 45 Example 4 90 20 45 Example 5 90 8.5 45 Example 6 100 14 45 Example 7 100 20 60

[0066] The polyether monomers prepared in the above examples were subjected to relevant index analysis tests to verify product performance. The test results are shown in Table 2 below:

[0067] Table 2 Polyether monomer product index test results

[0068]

[0069]

[0070] From the analysis of the test results in Table 2, it can be seen that the performance indicators of the low-air entraining TPEG polyether macromonomer of the present invention are qualified and meet the requirements, and the added defoaming agent has no obvious effect on the product quality.

[0071] The TPEG polyether macromonomer obtained in the above example was polymerized to obtain a polycarboxylic acid-based water reducer. The product application performance was verified by combining the slurry flowability test, concrete strength test and air content test. The test results are shown in Tables 3 and 4 below:

[0072] Table 3 Comparison of polycarboxylate water-reducing agent pure slurry with different defoamer dosages

[0073] Performance Indicators Pure slurry fluidity / mm Appearance Description Example 1 235 There are a lot of bubbles, the size is uneven Example 2 235 There are a few small bubbles, uniform in size Example 3 232 No bubbles on the surface Example 4 228 No bubbles on the surface Example 5 230 There are a lot of bubbles, the size is uneven Example 6 235 There are a lot of bubbles, the size is uneven Example 7 240 There are a few small bubbles, uniform in size

[0074] Table 4 Comparison of concrete performance with different defoamer dosages

[0075]

[0076] It can be seen from Table 3 that the net slurry fluidity of the polycarboxylic acid water-reducing agent prepared by TPEG polyether macromonomer with different defoamer dosages is not significantly different, and is maintained at about 230 mm. In addition, the defoaming effect is significant as the defoamer dosage increases.

[0077] It can be seen from Table 4 that when no defoamer is introduced, the air content of concrete is as high as 3.0%. When 8.5ppm of the total amount of polyether monomer is added as defoamer, the air content drops rapidly to 1.7%. At this time, there are fewer bubbles on the surface of concrete, and the bubbles are uniform in size, and the strength is significantly improved.

[0078] The increase in air content in concrete increases the porosity of the cement paste, which reduces the compressive strength. The reduction in concrete compressive strength is not only related to the increased air content, but also to the porous structure that attracts the air bubbles: the smaller the average pore size, the slower the strength decreases.

[0079] As the temperature of defoamer addition increases, the effect of defoamer becomes worse and worse, and it has little effect on reducing the air content and reducing the apparent bubbles in concrete. This is because as the temperature increases, the defoamer breaks down and the defoaming effect is greatly reduced.

[0080] When the introduced defoamer dosage reaches 8.5ppm and the addition temperature is 85℃, the obtained TPEG type polycarboxylate water reducer has moderate air content, and appropriate small bubbles are retained in the concrete, which has better working performance, enhances the strength of the concrete and makes the surface of the concrete more beautiful.

[0081] The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention should be defined by the claims.

Claims

1. An emulsion defoamer, characterized in that: The main components by weight include: 10 to 20 parts of organic polysiloxane, 1 to 5 parts of emulsifier, 2 to 10 parts of thickener, and 60 to 80 parts of solvent; The emulsifier is one or a combination of sorbitan monostearate, sodium lauryl sulfate, polyoxyethylene ether, polyvinyl alcohol, and sorbitan monooleate; The thickener is one or a combination of carboxymethyl cellulose, sodium polyacrylate, tragacanth gum, sodium starch phosphate, hydroxypropyl methylcellulose, and sodium alginate; Wherein, the solvent is water.

2. A low air entraining TPEG polyether macromonomer, characterized in that: The invention comprises the emulsion defoamer according to claim 1, wherein the proportion of the emulsion defoamer in the TPEG polyether macromonomer is 8.5 to 20 ppm:

1.

3. A low air entraining TPEG polyether macromonomer according to claim 2, characterized in that: The proportion of the emulsion defoamer in the TPEG polyether macromonomer is preferably 8.5 ppm.

4. A method for preparing a low-air entraining TPEG polyether macromonomer, characterized in that: Weighing the organopolysiloxane, emulsifier, thickener and solvent according to a certain weight and mixing them evenly to obtain a uniform emulsion defoamer, and then adding the prepared emulsion defoamer into the liquid TPEG polyether macromonomer according to the addition ratio; The proportion of the emulsion defoamer in the TPEG polyether macromonomer is 8.5 to 20 ppm:

1.

5. The method for preparing a low-air entraining TPEG polyether macromonomer according to claim 4, characterized in that: The proportion of the emulsion defoamer in the TPEG polyether macromonomer is preferably 8.5 ppm.

6. The method for preparing a low-air entraining TPEG polyether macromonomer according to claim 4, characterized in that: The mixing time of the emulsion defoamer and the TPEG polyether macromonomer is 30 to 60 minutes.

7. The method for preparing a low-air entraining TPEG polyether macromonomer according to claim 4, characterized in that: The addition temperature of the emulsion defoamer is 85°C to 100°C.

8. The method for preparing a low-air entraining TPEG polyether macromonomer according to claim 7, characterized in that: The addition temperature of the emulsion defoamer is preferably 85°C.

9. An application of a low-air entraining TPEG polyether macromonomer, characterized in that: The low air entraining TPEG polyether macromonomer described in claim 2 is used to carry out polymerization reaction to prepare a polycarboxylic acid water reducer.

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