Concrete release agent and preparation method thereof

Abstract

The present invention provides a concrete release agent and a preparation method thereof. Specifically, the concrete release agent comprises, based on its total weight, 25-40% by weight of a 40°C kinematic viscosity of 1-20 mm 2 / s between the base oil, the base oil is selected from mineral oil, synthetic oil or a combination thereof; 5-10% by weight of a non-ionic polyurethane resin, the non-ionic polyurethane resin is C 6‑10 The concrete release agent according to the embodiment of the present invention has good demoulding performance, and the concrete demoulding treated by the concrete release agent has good self-curing ability during the curing process, and the concrete finally cured has enhanced mechanical properties.

Description

Technical Field

[0001] The invention relates to the technical field of concrete industry, and in particular to a concrete release agent and a preparation method thereof. Background Art

[0002] In concrete construction, the use of release agents is crucial to improving construction efficiency and concrete molding quality. The main function of concrete release agents is to reduce the adhesion between concrete and the formwork so that the concrete can be demoulded smoothly after solidification while maintaining the integrity and finish of the concrete surface. Some excellent release agents can form a uniform isolation film between concrete and the formwork, reducing the adhesion between the two, which is conducive to component demoulding. This isolation effect not only helps to maintain the integrity and finish of the concrete surface, but also improves demoulding efficiency.

[0003] There are many types of release agents on the market, including water-based, oil-based, emulsified and other types of release agents. However, there are still some problems in the use of existing release agents. For example, some types of release agents have poor demoulding effects on concrete materials. In addition, pure oil release agents, such as hydraulic oil, machine oil, and lubricating oil, although they have good demoulding performance, are prone to cause the surface of concrete to be rough and the number of pores to increase. The increase in these pores will in turn reduce the mechanical properties of concrete.

[0004] In addition, the curing conditions of concrete curing are crucial to the final performance of concrete. Curing conditions (including temperature and humidity) directly affect the hydration reaction of cement, thereby affecting the strength and durability of concrete. For example, standard curing conditions usually refer to maintaining the temperature at 20℃±2℃ and the humidity not less than 90% within 28 days. If the curing conditions are not suitable, such as the temperature is too low or too high, and the humidity is too high or too low, it may cause cracks or pores on the surface of the concrete, and even a decrease in strength. The high concrete curing curing conditions in the existing technology pose challenges to construction efficiency, resource conservation and environmental protection.

[0005] Therefore, it is of great significance to develop a concrete release agent with good demoulding performance, good self-curing ability of the treated concrete during the curing process, and enhanced mechanical properties of the cured concrete. Summary of the invention

[0006] Based on the technical problems described above, the purpose of the present invention is to provide a concrete release agent and a preparation method thereof. The concrete release agent according to the embodiment of the present invention has good demoulding performance and can be easily demoulded from the template. In addition, the concrete demoulded by the concrete release agent has good self-curing ability during the curing process, and does not require high temperature-humidity curing conditions. In addition, the concrete finally cured has enhanced mechanical properties.

[0007] Specifically, according to one aspect of the present invention, there is provided a concrete release agent, the concrete release agent comprising, based on its total weight:

[0008] 25-40% by weight of kinematic viscosity at 40°C in the range of 1-20 mm 2 / s base oil, the base oil is selected from mineral oil, synthetic oil or a combination thereof;

[0009] 5-10% by weight of a nonionic polyurethane resin, wherein the nonionic polyurethane resin is C 6-10 Polymerization products of diols and aliphatic diisocyanates;

[0010] 0.5-2.5 wt% emulsifier;

[0011] 1-2 wt% penetrant;

[0012] 1-5% by weight of a defoamer;

[0013] 2-4 wt% of a rust inhibitor; and

[0014] The remaining amount of water.

[0015] According to another aspect of the present invention, there is provided a method for preparing a concrete release agent, the method comprising the following steps:

[0016] (1) mixing the above-mentioned nonionic polyurethane resin, emulsifier and part of water under stirring, and heating the obtained mixture at 60-80° C. for 2-3 hours to obtain a pre-emulsified emulsion; and

[0017] (2) adding the base oil, the penetrant, the defoamer, the rust inhibitor and the remaining water to the pre-emulsified emulsion under stirring, and heating the obtained mixture at 90-110° C. for 2-4 hours to obtain the concrete release agent in the form of an emulsion.

[0018] Compared with the prior art in this field, the advantages of the present invention are:

[0019] 1. Good demoulding performance: The concrete release agent provided by the present invention can form a uniform isolation film on the surface of the template, reduce the adhesion between the concrete and the template, thereby facilitating the demoulding of the component and maintaining the integrity and smoothness of the concrete shape.

[0020] 2. Concrete self-curing ability: Concrete treated with the release agent of the present invention has good self-curing ability during the curing process, which means that the concrete is less dependent on high humidity curing conditions during the curing process, which helps to improve construction efficiency and save resources. Due to the reduced dependence on high humidity curing conditions, the concrete release agent of the present invention can achieve good concrete performance under lower curing conditions, which helps to reduce construction costs, save water resources, reduce energy consumption, and meet the requirements of environmental protection and energy saving.

[0021] 3. Enhanced concrete mechanical properties: The final cured concrete has enhanced mechanical properties because the specific non-ionic polyurethane resin and / or humic acid or humate can form a protective film on the concrete surface and enter the concrete surface with the penetrant to improve the density of the concrete.

[0022] 4. Strong adaptability: The release agent of the present invention is suitable for different types of concrete and formwork materials and has strong adaptability.

[0023] 5. Easy to prepare and apply: The preparation method of the present invention is simple and easy to operate, and the application process of the release agent is simple and easy for construction workers to operate. DETAILED DESCRIPTION

[0024] It should be understood that, without departing from the scope or spirit of the present disclosure, those skilled in the art can conceive of other various embodiments and can modify them according to the teachings of this specification. Therefore, the following specific embodiments are not intended to be limiting.

[0025] Unless otherwise indicated, all numbers used in the specification and claims to represent feature sizes, quantities and physicochemical properties should be understood as being modified by the term "about" in all cases. Therefore, unless otherwise indicated, the numerical parameters listed in the above specification and the attached claims are approximate values, and those skilled in the art can use the teachings disclosed herein to seek to obtain the desired properties and appropriately change these approximate values. The use of numerical ranges expressed as endpoints includes all numbers within the range and any range within the range, for example, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4 and 5, etc.

[0026] As mentioned above, there are still some problems in the application of existing release agents. Therefore, developing a concrete release agent with good demoulding performance, good self-curing ability of the treated concrete during the curing process, and enhanced mechanical properties of the cured concrete is a hot direction in the development of release agent products.

[0027] The inventors of the present invention have found through systematic research that by using a specific 40°C kinematic viscosity of 1-20 mm 2 The combination of a base oil with a specific nonionic polyurethane resin between 100 μm and 100 μm can provide a concrete release agent with good demoulding performance, and the treated concrete has good self-curing ability and has enhanced mechanical properties after curing. Without being bound by theory, it is believed that the concrete release agent containing the specific base oil and the specific nonionic polyurethane resin can form a uniform isolation film on the surface of the template, reduce the adhesion between the concrete and the template (especially the steel template), thereby facilitating the demoulding of the component and maintaining the integrity and smoothness of the concrete shape. At the same time, this release agent has a good improvement effect on the apparent quality of concrete and can reduce the number and size of pores on the surface of concrete. In particular, the specific nonionic polyurethane resin can reduce water volatilization during the concrete curing process, regulate and improve the hydration process of cement, thereby reducing the demand for concrete curing and curing conditions. In addition, the specific nonionic polyurethane resin can also enhance the mechanical properties of concrete, such as rebound strength, compressive strength, etc., because it can form a protective film on the surface of concrete and enter the surface of concrete with the penetrant, which helps to improve the density of concrete.

[0028] Specifically, according to one aspect of the present invention, there is provided a concrete release agent, the concrete release agent comprising, based on its total weight:

[0029] 25-40% by weight of kinematic viscosity at 40°C in the range of 1-20 mm 2 / s base oil, the base oil is selected from mineral oil, synthetic oil or a combination thereof;

[0030] 5-10% by weight of a nonionic polyurethane resin, wherein the nonionic polyurethane resin is C 6-10 Polymerization products of diols and aliphatic diisocyanates;

[0031] 0.5-2.5 wt% emulsifier;

[0032] 1-2 wt% penetrant;

[0033] 1-5% by weight of a defoamer;

[0034] 2-4 wt% of a rust inhibitor; and

[0035] The remaining amount of water.

[0036] The concrete release agent according to the technical solution of the present invention comprises a 40° C. kinematic viscosity of 1-20 mm 2 / s as a necessary demoulding component. "40℃ kinematic viscosity" is an important parameter for characterizing oil products, which characterizes the flow properties of the oil product at a temperature of 40℃. The 40℃ kinematic viscosity is usually expressed in mm² / s (square millimeters per second). The concrete demoulding agent according to the technical solution of the present invention contains 25-40% by weight of a 40℃ kinematic viscosity of 1-20 mm 2 In order to simultaneously achieve good demoulding properties, good concrete self-curing properties, and good concrete mechanical properties, the concrete release agent according to the technical solution of the present invention contains preferably 28-35 wt %, more preferably 30-33 wt % of a base oil with a kinematic viscosity of 1-20 mm at 40°C. 2 / s. Preferably, the base oil is selected from mineral oil, synthetic oil or a combination thereof. The mineral oil can be a hydrocarbon mixture extracted or refined from petroleum. Preferably, in order to achieve a balance between good demoulding properties, good concrete self-curing properties and good concrete mechanical properties, the base oil has a kinematic viscosity of 1.5-2 mm at 40°C. 2 / s of kerosene, or the base oil has a kinematic viscosity of 12-15 mm at 40°C 2 / s engine lubricating oil between.

[0037] The concrete release agent according to the technical solution of the present invention comprises a specific nonionic polyurethane resin as the above-mentioned 40° C. kinematic viscosity of 1-20 mm 2 / s is an essential release agent component used in combination with a base oil of between 5% and 10% by weight. According to the technical solution of the present invention, the concrete release agent contains 5-10% by weight of the non-ionic polyurethane resin. In order to simultaneously achieve good demoulding properties, good concrete self-curing properties, and good concrete mechanical properties, the concrete release agent preferably contains 6-10% by weight, more preferably 6-8% by weight of the non-ionic polyurethane resin.

[0038] Preferably, the specific nonionic polyurethane resin is C 6-10 The polymerization product of diols and aliphatic diisocyanates. 6-10 The reaction between diols and aliphatic diisocyanates is a typical reaction in polyurethane synthesis. The inventors of the present invention have found that when C 6-10When the polymerization product of diol and aliphatic diisocyanate is used as the nonionic polyurethane resin component for concrete release agent, the self-curing property of concrete and the mechanical properties of concrete can be improved. When the polymerization product of diol with less than 6 carbon atoms and aliphatic diisocyanate is used as the nonionic polyurethane resin component, the demoulding property is greatly deteriorated, and part of the film formed by the demoulding agent will adhere to the formwork, making demoulding difficult; when the polymerization product of diol with more than 10 carbon atoms and aliphatic diisocyanate is used as the nonionic polyurethane resin component, the mechanical properties of the cured concrete are significantly reduced.

[0039] Preferably, the C 6-10 The diol is a straight chain C 6-10 According to certain preferred embodiments of the present invention, the C 6-10 The diol is one or more of 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol and 1,10-decanediol. In order to achieve good demoulding properties, good concrete self-curing properties and good concrete mechanical properties at the same time, the specific nonionic polyurethane resin is more preferably C 8-10 The polymerization product of a diol and an aliphatic diisocyanate. Most preferably, the C 6-10 The diol is 1,8-octanediol.

[0040] According to certain preferred embodiments of the present invention, the aliphatic diisocyanate is selected from one or more of hexamethylene diisocyanate, isophorone diisocyanate and dicyclohexylmethane diisocyanate. More preferably, in order to simultaneously achieve good demoulding properties, good concrete self-curing properties and good concrete mechanical properties, the aliphatic diisocyanate is hexamethylene diisocyanate.

[0041] There is no particular restriction on the source of the specific nonionic polyurethane resin, which can be obtained through commercial channels or prepared according to conventional chemical synthesis methods. For example, the specific nonionic polyurethane resin according to the present invention can be obtained according to the polyurethane preparation method between diols and diisocyanates well known in the field of organic chemistry.

[0042] In order to simultaneously achieve good demoulding properties, good concrete self-curing properties and good concrete mechanical properties, the weight average molecular weight of the non-ionic polyurethane resin is in the range of 2000-35000, preferably 3000-25000, more preferably 8000-16000.

[0043] In addition, the concrete release agent according to the technical solution of the present invention contains an emulsifier as an essential component. In the present invention, the main function of adding an emulsifier to the release agent is to evenly disperse the oil phase (such as base oil, etc.) in the release agent in a very fine particle form in a continuous water phase to form a stable emulsion. This structural characteristic enables the release agent to form a uniform film between the template and the concrete workpiece, thereby reducing the adhesion between the template and the concrete workpiece and achieving easy demoulding. According to certain preferred embodiments of the present invention, the emulsifier is selected from one or more of stearates, dodecyl sulfates and dodecylbenzene sulfonates. Preferably, in order to simultaneously achieve good demoulding properties, good concrete self-curing properties and good concrete mechanical properties, the emulsifier contains sodium stearate and sodium dodecyl sulfate. The concrete release agent contains 0.5-2.5% by weight, preferably 1-2% by weight, and more preferably 1.2-1.8% by weight of the above-mentioned emulsifier based on its total weight.

[0044] In addition, the concrete release agent according to the technical solution of the present invention contains a penetrant as an essential component. The main function of adding a penetrant to the release agent is to improve the demoulding effect, enhance the penetration ability of the release agent, and enable the release agent to more effectively penetrate between the template and the concrete workpiece, thereby reducing the adhesion and achieving smooth demoulding. In particular, the inventors of the present invention have found in their research that by specifically selecting the type of penetrant (specifically, the penetrant is selected from one or more of sulfonated castor oil, polysorbate and fatty alcohol), the specifically selected penetrant can even further promote or carry the non-ionic polyurethane resin into the surface interior of the concrete, which helps to further improve the compactness of the concrete, thereby improving its compressive strength. The concrete release agent contains 1-2% by weight, preferably 1-1.5% by weight of the above-mentioned penetrant based on its total weight.

[0045] Further, the concrete release agent according to the technical solution of the present invention comprises a defoamer as an essential component. The main function of adding a defoamer to the release agent is to eliminate the foam generated during the application of the release agent, to ensure the smoothness of the demoulding process and the consistency of the product quality. The generation of foam may affect the demoulding effect, resulting in uneven distribution of the release agent, thereby affecting the quality of the finished product. The defoamer accelerates the bursting of the foam by reducing the surface tension, and has good compatibility, is compatible with various types of release agents, and does not produce chemical reactions. Preferably, the defoamer is selected from one or more of an organosilicon defoamer, a polyether defoamer, and a silicone defoamer. A specific example of an organosilicon defoamer that can be used as a defoamer in the present invention is polydimethylsiloxane (CAS No.: 107-51-7). The concrete release agent contains 1-5% by weight, preferably 2-3.5% by weight of the above-mentioned penetrant based on its total weight.

[0046] According to certain preferred embodiments of the present invention, the concrete release agent comprises a rust inhibitor as an essential component. The main function of adding a rust inhibitor to the concrete release agent is to protect the mold from rust, extend the service life of the template, and ensure the quality of the concrete surface. In addition, the rust inhibitor can form a protective film to prevent water and oxygen from contacting the mold surface, thereby slowing down or preventing the occurrence of rust. The rust inhibitor also helps to improve the appearance quality of concrete and make the concrete surface smoother. Preferably, the rust inhibitor is selected from one or more of sodium benzoate, triethanolamine, triethanolamine oleic acid and triethanolamine borate. The concrete release agent contains 2-4% by weight, preferably 3-3.5% by weight of the above-mentioned rust inhibitor based on its total weight.

[0047] In addition to the above-mentioned components, according to certain preferred embodiments of the present invention, the concrete release agent may optionally contain humic acid or humate. The inventors of the present invention surprisingly found in their research that humic acid or humate as a component in the concrete release agent can not only contribute to the demoulding ability, but also significantly improve the self-curing ability of the treated concrete during the curing process and the mechanical strength of the resulting concrete. Without being bound by theory, it is believed that this is due to the fact that humic acid contains a variety of functional groups, such as carboxyl and phenolic hydroxyl groups, which can react with calcium ions (Ca 2+) in cement. 2+ ) and aluminum ions (Al 3+ ) react to form a stable complex or chelate, thereby affecting the hydration process of concrete. This effect can improve the microstructure of the concrete paste, increase the density, and thus enhance the strength of the concrete. On the other hand, it is possible to regulate the volatilization of water inside the concrete, and even form a protective layer to reduce the evaporation loss of surface water, thereby improving the self-curing ability of the concrete. The present invention further improves the self-curing ability and mechanical properties of concrete by introducing humic acid or humate, which is not recognized in the prior art.

[0048] In order to achieve good demoulding properties, good concrete self-curing properties and good concrete mechanical properties at the same time, the concrete release agent also contains 2.5-6% by weight, preferably 3-5% by weight of humic acid or humate. Specifically, the humate is sodium humate, potassium humate or a combination thereof. The humic acid or humate that can be used in the present invention can be commercially available or prepared according to known methods.

[0049] Preferably, the concrete release agent according to the present invention is an oil-in-water emulsion.

[0050] According to another aspect of the present invention, there is provided a method for preparing a concrete release agent, the method comprising the following steps:

[0051] (1) mixing the above-mentioned nonionic polyurethane resin, emulsifier and part of water under stirring, and heating the obtained mixture at 60-80° C. for 2-3 hours to obtain a pre-emulsified emulsion; and

[0052] (2) adding the base oil, the penetrant, the defoamer, the rust inhibitor and the remaining water to the pre-emulsified emulsion under stirring, and heating the obtained mixture at 90-110° C. for 2-4 hours to obtain the concrete release agent in the form of an emulsion.

[0053] According to certain preferred embodiments of the present invention, in the above steps (1) and (2), the stirring is performed at a rotation speed of 2000-5000 rpm.

[0054] According to the present invention, the above method adopts a distributed emulsification (primary pre-emulsification (1) - secondary full emulsification (2)) process, and the concrete release agent obtained by the above process has further improved demoulding properties, concrete self-curing properties and mechanical properties.

[0055] Preferably, the volume ratio of the water added in step (1) to the water added in step (2) is in the range of 1:2 to 1:8. The inventors of the present invention have found that by controlling the volume ratio of water defined above, a more stable concrete release agent emulsion is obtained.

[0056] According to certain preferred embodiments of the present invention, the nonionic polyurethane resin is in the form of an emulsion as an aqueous dispersion. Specifically, the nonionic polyurethane resin can be prepared into an emulsion form during the preparation process to facilitate the process operation of the subsequent steps.

[0057] The following detailed description is intended to illustrate the present disclosure by way of example only and not by way of limitation.

[0058] Specific embodiment 1 is a concrete release agent, which comprises, based on its total weight:

[0059] 25-40% by weight of kinematic viscosity at 40°C in the range of 1-20 mm 2 / s base oil, the base oil is selected from mineral oil, synthetic oil or a combination thereof;

[0060] 5-10% by weight of a nonionic polyurethane resin, wherein the nonionic polyurethane resin is C 6-10 Polymerization products of diols and aliphatic diisocyanates;

[0061] 0.5-2.5 wt% emulsifier;

[0062] 1-2 wt% penetrant;

[0063] 1-5% by weight of a defoamer;

[0064] 2-4 wt% of a rust inhibitor; and

[0065] The remaining amount of water.

[0066] Specific embodiment 2 is a concrete release agent according to specific embodiment 1, wherein the base oil has a kinematic viscosity of 1.5-2 mm at 40°C. 2 / s of kerosene, or the base oil has a kinematic viscosity of 12-15 mm at 40°C 2 / s engine lubricating oil between.

[0067] Specific embodiment 3 is a concrete release agent according to specific embodiment 1, wherein the C 6-10 The diol is a straight chain C 6-10 Diols.

[0068] Specific embodiment 4 is a concrete release agent according to specific embodiment 1, wherein the C 6-10 The diol is one or more of 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol and 1,10-decanediol.

[0069] Specific embodiment 5 is a concrete release agent according to specific embodiment 1, wherein the C 6-10 The diol is 1,8-octanediol.

[0070] Specific embodiment 6 is a concrete release agent according to specific embodiment 1, wherein the aliphatic diisocyanate is selected from one or more of hexamethylene diisocyanate, isophorone diisocyanate and dicyclohexylmethane diisocyanate.

[0071] Specific embodiment 7 is the concrete release agent according to specific embodiment 1, wherein the aliphatic diisocyanate is hexamethylene diisocyanate.

[0072] Specific embodiment 8 is the concrete release agent according to specific embodiment 1, wherein the weight average molecular weight of the non-ionic polyurethane resin is in the range of 2000-35000.

[0073] Specific embodiment 9 is the concrete release agent according to specific embodiment 1, wherein the emulsifier is selected from one or more of stearate, dodecyl sulfate and dodecylbenzene sulfonate.

[0074] Embodiment 10 is the concrete release agent according to embodiment 1, wherein the emulsifier comprises sodium stearate and sodium lauryl sulfate.

[0075] Specific embodiment 11 is the concrete release agent according to specific embodiment 1, wherein the penetrant is selected from one or more of sulfonated castor oil, polysorbate and fatty alcohol.

[0076] Specific embodiment 12 is a concrete release agent according to specific embodiment 1, wherein the defoaming agent is selected from one or more of silicone defoaming agents, polyether defoaming agents and silicone defoaming agents.

[0077] Specific embodiment 13 is a concrete release agent according to specific embodiment 1, wherein the defoaming agent is polydimethylsiloxane.

[0078] Specific embodiment 14 is a concrete release agent according to specific embodiment 1, wherein the rust inhibitor is selected from one or more of sodium benzoate, triethanolamine, triethanolamine oleic acid and triethanolamine borate.

[0079] Specific embodiment 15 is the concrete release agent according to specific embodiment 1, wherein the concrete release agent further comprises 2.5-6 weight % of humic acid or humate.

[0080] Specific embodiment 16 is a concrete release agent according to specific embodiment 15, wherein the humate is sodium humate, potassium humate or a combination thereof.

[0081] Specific embodiment 17 is a concrete release agent according to specific embodiment 1, wherein the concrete release agent is an oil-in-water emulsion.

[0082] Specific embodiment 18 is a method for preparing the concrete release agent according to any one of specific embodiments 1-17, the method comprising the following steps:

[0083] (1) mixing the nonionic polyurethane resin, the emulsifier and a portion of water under stirring, and heating the resulting mixture at 60-80° C. for 2-3 hours to obtain a pre-emulsified emulsion; and

[0084] (2) adding the base oil, the penetrant, the defoamer, the rust inhibitor and the remaining water to the pre-emulsified emulsion under stirring, and heating the obtained mixture at 70-90° C. for 2-4 hours to obtain the concrete release agent in the form of an emulsion.

[0085] Embodiment 19 is the method according to embodiment 18, wherein the nonionic polyurethane resin is in the form of an emulsion as an aqueous dispersion.

[0086] Specific embodiment 20 is the method according to specific embodiment 18, wherein in step (1) and step (2), the stirring is performed at a rotation speed of 2000-5000 rpm.

[0087] Embodiment 21 is a method according to embodiment 18, wherein the volume ratio of water added in step (1) to water added in step (2) is in the range of 1:2 to 1:8.

[0088] The present invention is described in more detail below in conjunction with the examples. It should be noted that these descriptions and examples are intended to facilitate the understanding of the present invention, rather than to limit the present invention. The protection scope of the present invention shall be subject to the attached claims. Example

[0089] In the present invention, unless otherwise specified, all reagents used are commercially available products and are used directly without further purification.

[0090] Preparation Example 1-Synthesis of nonionic polyurethane resin emulsion containing ionic polyurethane resin A

[0091] In Preparation Example 1, nonionic polyurethane resin A was prepared according to a conventional prior art method. Specifically, about 292 g of 1,8-octanediol and about 336 g of hexamethylene diisocyanate were added to a nitrogen-treated anhydrous four-necked flask, and then 80 g of acetone was added and mixed thoroughly. Subsequently, the reaction system was gradually heated to 60-70° C. and the mixture was stirred for reaction for about 5 hours to prepare a prepolymer.

[0092] Then, the temperature of the prepolymer is reduced to about 50°C, and 600 g of acetone and 2.2 g of stannous octoate are added to the system. Subsequently, the temperature is raised to 65°C and the mixture is stirred to react for about 3 hours. When the isocyanate group (-NCO) content in the prepolymer generated by the reaction no longer changes, the temperature is lowered to room temperature to obtain a nonionic polyurethane. Then, 700 g of deionized water is added to the nonionic polyurethane, and high-speed dispersion is obtained to obtain an aqueous dispersion. After removing acetone in the system by distillation, 4.5 g of emulsifier Tween 20 is added to obtain a nonionic polyurethane resin emulsion containing ionic polyurethane resin A. The weight average molecular weight of the nonionic polyurethane resin measured by conventional chemical methods (e.g., gel permeation chromatography (GPC)) is about 15,000.

[0093] Preparation Example 2-Synthesis of nonionic polyurethane resin emulsion containing ionic polyurethane resin B

[0094] A nonionic polyurethane resin emulsion containing ionic polyurethane resin B was prepared in a similar manner to Preparation Example 1, except that 1,4-butanediol was used instead of 1,8-octanediol. The weight average molecular weight of the nonionic polyurethane resin measured by conventional chemical methods (e.g., gel permeation chromatography (GPC)) was 14800.

[0095] Preparation Example 3 - Preparation of concrete slurry for performance testing

[0096] 300 parts by weight of Portland cement (purchased from Anhui Conch Cement Co., Ltd.), 500 parts by weight of medium sand, 70 parts by weight of fly ash and 150 parts by weight of water were fully mixed to obtain concrete slurry for the following performance tests.

[0097] Test Method

[0098] 1. Demolding performance test

[0099] According to the methods described in detail below, each concrete release agent prepared in the following examples and comparative examples was tested for demoulding properties, concrete self-curing properties and concrete mechanical properties.

[0100] Specifically, first, a plurality of steel plates are arranged in the form of a steel mold. For each of the following examples and comparative examples, the prepared concrete release agent is evenly coated on the inner wall of the steel mold and dried at room temperature. After the steel mold coated with the release agent is completely dried, the concrete slurry prepared in the above Preparation Example 3 is poured into the steel mold until the mold is completely filled. Then, a plastic film is used to cover the poured concrete to maintain a certain humidity and a suitable temperature, which is conducive to the crystallization and evaporation of the concrete.

[0101] After 48 hours, the operator will perform the demoulding operation and score the demoulding difficulty according to the following criteria:

[0102] Level 1 (Excellent): Easy demoulding;

[0103] Level 2 (good): smooth demoulding;

[0104] Level 3 (acceptable): demoulding is difficult and requires greater force;

[0105] Rating 4 (poor): Mold release was difficult, and a portion of the film formed by the release agent adhered to the mold.

[0106] The above demoulding difficulty level is used to evaluate the demoulding performance of the concrete release agent.

[0107] After demoulding, ten observers visually observed the concrete surface with a certain hardness after demoulding and scored the surface condition of the concrete according to the following criteria:

[0108] Level 1 (Excellent): Smooth surface, no tiny pores or cracks;

[0109] Level 2 (good): The surface is relatively smooth, with a few tiny pores or cracks;

[0110] Level 3 (acceptable): The surface is rough, with tiny pores or cracks;

[0111] Grade 4 (poor): The surface is rough and has a lot of pores and cracks.

[0112] The above concrete surface state after demoulding is used to evaluate the demoulding performance of the concrete release agent.

[0113] 2. Concrete self-curing performance test

[0114] After the demoulding operation in the above steps, the demoulding concrete with a certain hardness is covered with a plastic film. The covered concrete is placed at room temperature (about 23°C) for 28 days (28d) to achieve full curing of the concrete. No watering curing measures are carried out during this period.

[0115] After 28 days, the plastic film was removed and ten observers visually inspected the fully hardened concrete surface and scored the surface condition of the concrete according to the following criteria:

[0116] Grade 1 (Excellent): Smooth surface, no tiny pores or cracks;

[0117] Level 2 (good): The surface is relatively smooth, with a few tiny pores or cracks;

[0118] Level 3 (acceptable): The surface is rough, with tiny pores or cracks;

[0119] Level 4 (poor): The surface is rough, with a lot of pores and even cracks.

[0120] The above fully hardened concrete surface state is used to evaluate the self-curing performance of the concrete release agent.

[0121] 3. Concrete mechanical properties test

[0122] After the self-curing performance evaluation described above, the mechanical properties of the fully hardened concrete were tested. Specifically, the 28d rebound strength (MPa) and carbonation depth (mm) of the concrete were tested according to the method described in the Technical Specification for Testing the Compressive Strength of Concrete by Rebound Method (JGJ / T 23-2011).

[0123] Example 1 (E1)

[0124] The nonionic polyurethane resin emulsion A prepared above, sodium stearate and sodium lauryl sulfate were added to 800 g of water under stirring at 3000 rpm and mixed thoroughly, and then the obtained mixture was heated at 65° C. for about 2.5 hours to obtain a pre-emulsified emulsion.

[0125] Then, kerosene (kinematic viscosity of 1.9 mm at 40°C) was added to the pre-emulsified emulsion under stirring at 3000 rpm. 2 / s), sulfonated castor oil, polydimethylsiloxane (CAS No.: 107-51-7), sodium benzoate and 1600 g of water, and the obtained mixture was heated at about 90° C. for 3 hours to obtain a concrete release agent 1 in the form of an emulsion.

[0126] In the concrete release agent 1 prepared above, based on the total weight thereof, the concrete release agent 1 comprises: 30 wt % of kerosene (with a kinematic viscosity of about 1.9 mm at 40° C.); 2 / s), 8 wt% of nonionic polyurethane resin A, 1.8 wt% of emulsifiers sodium stearate and sodium lauryl sulfate (wherein the weight ratio of sodium stearate and sodium lauryl sulfate is 3:1), 1.5 wt% of penetrant sulfonated castor oil, 2 wt% of defoamer polydimethylsiloxane and 3.5 wt% of rust inhibitor sodium benzoate, and the balance of water. The specific composition and content of the above concrete release agent 1 are shown in the following Table 1.

[0127] In addition, various properties of the concrete release agent 1 were tested according to the methods described in the demoulding performance test, concrete self-curing performance test and concrete mechanical performance test described in detail in the "Test Methods" section above. The test results are shown in Table 1 below.

[0128] Examples 2-10 (E2-E10) and Comparative Examples 1-6 (CE1-CE6)

[0129] Concrete release agents 2-10 and comparative concrete release agents 1-6 of Examples 2-10 (E2-E10) and Comparative Examples 1-6 (CE1-CE6) were prepared according to a method similar to that of Example 1 (E1). In addition, various properties of concrete release agents 2-10 and comparative concrete release agents 1-6 were tested according to the methods described in the demoulding performance test, concrete self-curing performance test, and concrete mechanical property test described in detail in the "Test Methods" section above. The test results are shown in Table 1 below.

[0130] In Comparative Example 5 (CE5), a comparative concrete release agent 5 was prepared according to a method similar to that of Example 1, except that the nonionic polyurethane resin emulsion containing ionic polyurethane resin B prepared in Preparation Example 2 was used instead of the nonionic polyurethane resin emulsion containing ionic polyurethane resin A prepared in Preparation Example 1. In addition, various properties of the comparative concrete release agent 5 were tested according to the methods described in the demoulding performance test, concrete self-curing performance test, and concrete mechanical property test described in detail in the "Test Methods" section above. The test results are shown in Table 1 below.

[0131] Comparative Example 6 (CE6) - Standard Curing Conditions

[0132] Comparative concrete release agent 6 of Comparative Example 6 (CE6) was prepared according to a method similar to Example 1, and demolding and sufficient curing operations were performed in a method similar to Example 1, except that after the demolding operation, a plastic film was used to cover the demolded concrete with a certain hardness, and the covered concrete was placed at room temperature (about 23° C.) for 28 days (28d) to achieve sufficient curing of the concrete, during which water was regularly poured on the concrete to maintain a humidity of about 90%. In addition, various properties of the comparative concrete release agent 6 were tested according to the methods described in the demolding performance test, concrete self-curing performance test, and concrete mechanical property test described in detail in the "Test Methods" section above. The test results are shown in Table 1 below.

[0133] Table 1 Types and ratios of raw materials, process conditions, and performance test results of Examples 1-10 (E1-E10) and Comparative Examples 1-6 (CE1-CE6)

[0134]

[0135] Note: Sodium humate powder comes from Shanxi Xinlitianxia Humic Acid Products Co., Ltd.

[0136] From the results of Examples 1-10 (E1-E10) shown in Table 1 above, it can be seen that when the concrete release agent is prepared according to the technical solution of the present invention, the obtained concrete release agent has good demoulding performance, the concrete demoulded by the concrete release agent has good self-curing ability during the curing process, and the concrete finally cured has enhanced mechanical properties.

[0137] In particular, by comparing the results of Example 1 (E1) with Example 10 (E10), it can be seen that when a specific amount of potassium humate powder is additionally added to the concrete release agent system, the self-curing performance and mechanical properties of the concrete are improved, especially, the 28d rebound strength increases from 42.5 MPa to 49.3 MPa, which is far beyond the expectations of those skilled in the art.

[0138] By comparing the results of Example 1 (E1) with Comparative Example 6 (CE6), it can be seen that compared with the test results of Comparative Example 6 (CE6) in which the humidity is maintained at 90% by regular watering during curing, the surface state grade of the fully hardened concrete of Example 1 (E1) without special humidification maintenance operation remains basically unchanged, and the mechanical properties are comparable. It can be seen that the concrete release agent according to the present invention provides good self-curing ability for concrete.

[0139] In addition, by comparing the results of Example 1 (E1) with Comparative Examples 1-4 (CE1-CE4), it can be seen that when the formula of the concrete release agent does not meet the range defined in the present invention, at least one of the demoulding properties of the concrete release agent and the mechanical properties of the finally cured concrete will be significantly deteriorated.

[0140] In addition, by comparing the results of Example 1 (E1) with Comparative Example 5 (CE5), it can be seen that when the polymerization product of a diol having a carbon number of less than 6 (i.e., 1,4-butanediol) and an aliphatic diisocyanate (i.e., hexamethylene diisocyanate) is used as the non-ionic polyurethane resin component, the demoulding property is greatly deteriorated, and in addition, the mechanical properties of the concrete finally obtained by curing are also significantly reduced.

[0141] Although specific embodiments have been shown and described in the present invention, it will be appreciated by those skilled in the art that various alternative and / or equivalent embodiments may be used to replace the specific embodiments shown and described without departing from the scope of the present invention. The present application is intended to include any improvements or changes to the specific embodiments discussed in the present invention. It will be appreciated by those skilled in the art that various modifications and changes may be made without departing from the scope of the present invention. Such modifications and changes are intended to fall within the scope of the present invention as defined in the appended claims.

Claims

1. A concrete release agent, characterized in that: The concrete release agent comprises, based on its total weight: 25-40% by weight of kinematic viscosity at 40°C in the range of 1-20 mm 2 / s base oil, the base oil is selected from mineral oil, synthetic oil or a combination thereof; 5-10% by weight of a nonionic polyurethane resin, wherein the nonionic polyurethane resin is C 6-10 Polymerization products of diols and aliphatic diisocyanates; 0.5-2.5 wt% emulsifier; 1-2 wt% penetrant; 1-5% by weight of a defoamer; 2-4 wt% of a rust inhibitor; and The remaining amount of water.

2. The concrete release agent according to claim 1, characterized in that The base oil has a kinematic viscosity of 1.5-2 mm at 40°C. 2 / s of kerosene, or the base oil has a kinematic viscosity of 12-15 mm at 40°C 2 / s engine lubricating oil between.

3. The concrete release agent according to claim 1, characterized in that The C 6-10 The diol is one or more of 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol and 1,10-decanediol.

4. The concrete release agent according to claim 1, characterized in that The aliphatic diisocyanate is selected from one or more of hexamethylene diisocyanate, isophorone diisocyanate and dicyclohexylmethane diisocyanate.

5. The concrete release agent according to claim 1, characterized in that: The weight average molecular weight of the nonionic polyurethane resin is in the range of 2,000-35,000.

6. The concrete release agent according to claim 1, characterized in that: The emulsifier is selected from one or more of stearate, dodecyl sulfate and dodecylbenzene sulfonate.

7. The concrete release agent according to claim 1, characterized in that: The penetrant is selected from one or more of sulfonated castor oil, polysorbate and fatty alcohol; The defoamer is selected from one or more of silicone defoamers and polyether defoamers; and The rust inhibitor is selected from one or more of sodium benzoate, triethanolamine, triethanolamine oleic acid and triethanolamine borate.

8. The concrete release agent according to claim 1, characterized in that: The concrete release agent further comprises 2.5-6% by weight of humic acid or humate.

9. The concrete release agent according to claim 8, characterized in that: The humate is sodium humate, potassium humate or a combination thereof.

10. A method for preparing a concrete release agent according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: (1) mixing the nonionic polyurethane resin, the emulsifier and a portion of water under stirring, and heating the resulting mixture at 60-80° C. for 2-3 hours to obtain a pre-emulsified emulsion; and (2) adding the base oil, the penetrant, the defoamer, the rust inhibitor and the remaining water to the pre-emulsified emulsion under stirring, and heating the obtained mixture at 70-90° C. for 2-4 hours to obtain the concrete release agent in the form of an emulsion.

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