Pickering emulsion for concrete demoulding and its preparation method

Abstract

The present invention discloses a Pickering emulsion for concrete demoulding and its preparation method, relating to the technical field of building materials. The raw material components of the Pickering emulsion of the present invention are as follows: 200 - 600 parts of base oil, 50 - 60 parts of composite emulsifier, 50 - 60 parts of co-emulsifier, 1 - 2 parts of pour point depressant component for the dispersed phase, 0.5 - 1 part of antioxidant, 8 - 10 parts of thixotropic stabilizing component for the continuous phase, 10 - 15 parts of color regulator, and 500 - 550 parts of water. The Pickering emulsion has excellent concrete demoulding performance, and at the same time also has the properties of self-curing of concrete and anti-ultraviolet performance, which can effectively improve the structural strength of concrete, extend the service life of concrete and ensure its appearance quality. The present invention solves the problems existing in traditional demoulding agents, and also provides additional functionality and aesthetics for concrete products, and is applicable to various building and infrastructure projects, having broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and particularly to a Pickering emulsion for concrete demoulding and a preparation method thereof. Background Art

[0002] With the continuous progress of the construction industry, the requirements for concrete are no longer limited to strength and workability, but are gradually moving towards higher appearance quality standards. To ensure excellent appearance quality of concrete, several key factors must be comprehensively considered: raw material selection, slump control, construction technology (especially pouring and vibration), formwork type and its surface treatment, and the type and quality of demoulding agents.

[0003] As a key material that plays a lubricating and isolating role at the interface between the formwork and concrete, the demoulding agent not only effectively reduces the adhesion between the concrete and the formwork, but also prevents formwork corrosion and wear, thus significantly improving the surface quality of the concrete. Different types of demoulding agents (such as oil-based, emulsion or wax-based) have a significant impact on the appearance effect of concrete, such as color consistency, smoothness, texture effect and cleanliness.

[0004] In practical engineering applications, the demoulding agent is usually applied to the surface of steel formwork or formwork of other materials by brushing or spraying before concrete pouring to ensure smooth demoulding of the concrete and achieve an ideal appearance effect. Selecting a suitable demoulding agent is crucial for achieving high-quality concrete appearance.

[0005] Currently, the requirements for demoulding agents in many engineering projects are not only to ensure non-sticking to the formwork during the demoulding stage, but also to set higher standards for the appearance of the concrete. An ideal concrete surface should be smooth and shiny, with small and few air bubbles, no sand lines and water patterns, and uniform color. Some projects even require the concrete appearance to reach a specific light gray standard color number. However, most demoulding agents on the market are difficult to meet these improved requirements simultaneously. Especially for emulsion-type demoulding agents, due to their thermodynamically unstable characteristics, they are prone to demulsification and stratification during storage, thus affecting the demoulding effect.

[0006] Research shows that solid particles (such as silica, carbon black, iron oxide and clay) can form a spatial distribution in the oil-water mixed system and adsorb on the interface of oil-water droplets to form a thin and elastic particle layer. This layer of particles effectively prevents the coalescence of droplets and gives the emulsion long-term kinetic stability. The emulsion prepared by introducing solid particles is called Pickering emulsion. Although Pickering emulsion has been widely used in the food, cosmetics, pharmaceutical and petroleum industries, its research and application in the field of concrete are still less. Summary of the Invention

[0007] The object of the present invention is to provide a Pickering emulsion applied to concrete demoulding and a preparation method thereof, so as to solve the problems existing in the above-mentioned prior art. The Pickering emulsion prepared by the present invention not only has excellent concrete demoulding performance and high-standard concrete appearance quality, but also can endow the concrete with self-curing and anti-ultraviolet properties, significantly improving the quality and durability of concrete components.

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] One of the technical solutions of the present invention is to provide a Pickering emulsion, which comprises the following raw material components in parts by mass:

[0010] 200 - 600 parts of base oil, 50 - 60 parts of compound emulsifier, 50 - 60 parts of co-emulsifier, 1 - 2 parts of dispersed phase pour point depressant component, 0.5 - 1 part of antioxidant, 8 - 10 parts of continuous phase thixotropic stabilizer component, 10 - 15 parts of color regulator, and 500 - 550 parts of water.

[0011] The Pickering emulsion of the present invention is an oil-in-water emulsion, the dispersed phase is the oil phase, and the continuous phase is the water phase;

[0012] The base oil includes mineral oil and vegetable oil;

[0013] The compound emulsifier includes polyoxyethylene hydrogenated castor oil CO-40, polyglycerol monooleate, decaglycerol monooleate, sorbitan monooleate, and kaolin.

[0014] In the present invention, the particle size of kaolin is preferably 2.5 μm - 5 μm.

[0015] The co-emulsifier includes one or a combination of two of medium-chain saturated fatty acids with 8 - 12 carbon atoms in the carbon chain and unsaturated fatty acids with 18 carbon atoms.

[0016] The dispersed phase pour point depressant component includes polymethacrylate T602HB.

[0017] The antioxidant includes one or a combination of two of dibutylhydroxytoluene and butylhydroxyanisole.

[0018] The continuous phase thixotropic stabilizer component includes one or a combination of two of magnesium aluminum silicate and magnesium lithium silicate.

[0019] As a further preference of the present invention, the mineral oil is naphthenic oil.

[0020] As a further preference of the present invention, the naphthenic oil is naphthenic oil 4010, and its kinematic viscosity (40 °C) is 145 mm 2 / s, and the pour point is -30 °C.

[0021] As a further preference of the present invention, the vegetable oil includes one or a combination of two or more of rapeseed oil, sunflower oil, and peanut oil.

[0022] As a further preference of the present invention, the medium-chain saturated fatty acid with 8-12 carbon atoms on the carbon chain includes one or several of n-octanoic acid, n-decanoic acid, or lauric acid; the unsaturated fatty acid with 18 carbon atoms is one or several of oleic acid, linoleic acid, or linolenic acid.

[0023] As a further preference of the present invention, the antioxidant is a complex of dibutylhydroxytoluene and butylhydroxyanisole with a mass ratio of 1:1.

[0024] As a further preference of the present invention, the color regulator includes titanium dioxide.

[0025] As a further preference of the present invention, the titanium dioxide is anatase titanium dioxide.

[0026] Naphthenic oil has good affinity with the metal template. When its emulsion forms a film on the template surface, it can be firmly adsorbed on the template surface, effectively reducing the adhesion force between the mold and the formed part, thereby improving the demolding performance of the formed part. Moreover, it does not react with various components in the concrete and only plays a role of isolation and lubrication during the forming process, which can reduce the surface roughness of the formed part. However, a large number of experiments have verified that various mineral oils represented by naphthenic oil have varying degrees of oil residue on the surface of the formed part after demolding, which will have an adverse impact on some projects with high requirements for surface finish. The introduction of the vegetable oil of the present invention can improve the apparent defects brought by the mineral oil while retaining the excellent lubricating effect of the mineral oil. Since the main components of the vegetable oil are esters formed by straight-chain higher fatty acids and glycerol, when the vegetable oil emulsion breaks and forms a film on the template surface and contacts the concrete, under the strong alkaline conditions of the cement system, triglycerides begin to hydrolyze and release fatty acids. The fatty acids will react with calcium ions in the cement to form calcium fatty acid soaps, which are evenly distributed on the concrete surface, making the appearance color of the concrete uniform and slightly white, and effectively improving the oil residue caused by naphthenic oil.

[0027] In the preparation of Pickering emulsions of the present invention, the selection of emulsifiers is not a simple compounding, but is based on the HLB emulsification method for calculation and selection. The HLB emulsification method is to prepare stable emulsions by selecting emulsifiers with appropriate HLB values. The HLB value (hydrophilic-lipophilic balance value) is used to represent the balance of hydrophilicity and lipophilicity of surfactants. The larger the value, the stronger the hydrophilicity, and the smaller the value, the stronger the lipophilicity. The selection principles of HLB values include three items: 1. Determine the HLB value required for the emulsification system: Select an appropriate HLB value according to the properties of the emulsification system (such as oil-in-water or water-in-oil). The HLB value of O / W (oil-in-water) emulsions is usually between 8 and 18, and the HLB value of W / O (water-in-oil) emulsions is usually between 3 and 6. The emulsions prepared in the present invention are O / W (oil-in-water) emulsions; 2. Determine the HLB value required for the emulsification of base oil. For example, the HLB value required for alkane mineral oil W / O emulsions is 4, and the HLB value required for O / W emulsions is 10. Another example is that the HLB value required for aromatic mineral oil W / O emulsions is 4, and the HLB value required for O / W emulsions is 12. The HLB range required for the combined base oil water-in-oil emulsions in the present invention is 11-13; 3. Select the best emulsification system: When selecting an emulsification system, a single emulsifier or a composite emulsifier can be selected. However, a single emulsifier emulsification system has the following key defects: (a) Poor stability: The stability of a single emulsifier is poor. The interfacial force between oil and water is low, and the arrangement density is low, making it easy to demulsify; (b) Performance limitations: The function of a single emulsifier is relatively single and it is difficult to meet various emulsification requirements. Low-HLB value emulsifiers can only prepare water-in-oil emulsions, and high-HLB value emulsifiers can only prepare oil-in-water emulsions. In addition, the prerequisite for preparing stable emulsions is that the HLB value of the emulsifier exactly corresponds to the HLB value required for the base oil it emulsifies, resulting in great difficulty; (c) Difficult to adjust: The HLB value (hydrophilic-lipophilic balance value) of a single emulsifier is fixed and difficult to adjust, and it cannot adapt to different emulsification requirements. Therefore, in view of the above defects, a pair of emulsifiers with a large difference in HLB values are usually selected and compounded in different proportions to test the most suitable HLB value for the emulsification system. After ensuring that the HLB value is fixed, other emulsifiers with different molecular structures and molecular weights are further added to enhance the intermolecular force at the oil-water interface and provide a closer arrangement, so as to further improve the stability of the emulsion. By using composite emulsifiers, the best combination can be determined by calculating the mixed HLB value. When the composite emulsifier has the same HLB value as that required for the emulsification of the base oil, relatively stable emulsions can be obtained. The calculation formula for the mixed HLB value is: HLB 混合 =∑(HLB i ×m i ), where HLB i and m i represent the HLB value of each surfactant and its mass proportion in the mixture respectively.

[0028] Based on the above two types of base oils, by reasonably compounding different types of emulsifiers, a more perfect molecular film structure can be formed during the emulsification process, enhancing the stability of the emulsion system. Different types of emulsifiers have differences in interfacial activity and molecular configuration. Compounding can give full play to the characteristics of each emulsifier and improve the stability of the emulsion system. Both polyglycerol monooleate and decaglycerol monooleate are polymers obtained by the esterification reaction of glycerol and monooleic anhydride. This substance has the characteristics of a non-ionic alkoxylated multifunctional emulsifier. The HLB of polyglycerol monooleate (C 27 H 52 O 8 ) is 7 - 8, and its molecular weight is 504.7. The HLB of decaglycerol monooleate (C 36 H 70 O 14 ) is 13.5 - 14, and its molecular weight is 726.9. Due to their similar structures, they have high compatibility when used as a composite emulsifier. The large HLB difference has a flexible regulatory effect on different base oils. The difference in molecular weight can further supplement the vacancies with small molecules on the basis of large molecules inserting into the oil-water interface, increasing the tightness of the molecular arrangement of the interfacial film. The main component of polyoxyethylene hydrogenated castor oil is the hydrophobic component polyoxyethylene glycerol trihydroxystearate. Additionally, it also contains a small amount of the hydrophobic component polyethylene glycol trihydroxystearate and unreacted castor oil, as well as the hydrophilic component free polyethylene glycol. Its HLB is 14 - 14.5. This complex molecular structure makes it have good dispersibility and stability in water. Span80 (sorbitan monooleate, C 24 H 44 O 6 ) is a non-ionic surfactant obtained by the esterification reaction of sorbitol and oleic acid. Span80 is hydrophobic and can only be used as a water-in-oil emulsifier when used alone. Its HLB value is 4.3, and its molecular weight is 429. The hydrophilic part (sorbitan) and hydrophobic part (oleate) in its molecular structure endow it with the characteristics of a surfactant. Similar to the usage method of the two polyglycerol monooleates, Span80 also needs to be compounded with a high-HLB emulsifier to prepare an oil-in-water emulsion of base oils with different required HLB values (in this invention, polyoxyethylene hydrogenated castor oil is used in combination with it). The smaller molecular weight can further enhance the tight arrangement of the oil-water interfacial film.

[0029] More preferably, as previously mentioned, kaolin can form a spatial distribution in the oil-water mixed system and adsorb on the interface of oil-water droplets, forming a thin and elastic particle layer. This layer of particles effectively prevents the coalescence of droplets and imparts long-term kinetic stability to the emulsion. Since kaolin itself is not dispersed in either the aqueous phase or the oil phase, the non-ionic surfactant sorbitan monooleate is used to modify kaolin in-situ. The sorbitan monooleate molecules are adsorbed on the hydrophilic surface of kaolin due to the hydrogen bond between the hydrophilic groups, and its hydrophobic tail is exposed away from the surface, thereby making the surface of kaolin particles effectively hydrophobic and inducing a steric effect, enabling it to act as a new surfactant to increase the arrangement density and strength of the oil-water interface. However, it should be noted that after mixing with Span80, only its surface is modified, and the total amount of hydrophobic groups in the mixture remains unchanged compared to pure Span80, so its HLB value will not change, that is, the HLB value of the mixture of the two is still 4.3, and it is only suitable for water-in-oil emulsions when used alone. In addition, when the emulsion is brushed onto the template surface to form a film, kaolin is also evenly dispersed and exposed on the template. Due to its high specific surface area and good dispersibility, it forms a uniform thin film on the mold surface, thereby reducing the friction between the mold and the molding material and promoting demolding. Moreover, the high-temperature resistance of kaolin also makes it perform well during the high-temperature curing and molding process, further improving the demolding effect.

[0030] The co-emulsifiers are all selected as low-molecular-weight straight-chain fatty acids. These fatty acids can insert into the vacancies in the arrangement of emulsifier molecules at the oil-water interface to form a denser arrangement, thereby reducing the particle size of the dispersed phase and enhancing the stability of the emulsion. The reason for defining them as co-emulsifiers is that although their addition can improve the stability of the emulsion, it will not affect the HLB value required for emulsion emulsification. In addition, this type of fatty acid is similar to vegetable oil, but it can directly react with calcium ions or calcium salts (such as calcium hydroxide, calcium carbonate, calcium sulfate) in cement without hydrolysis to form calcium fatty acid, and aluminum ions and fatty acid root ions in the concrete system will also react to form aluminum fatty acid, and are arranged in a specific orientation on the concrete surface. The above two reaction products can both improve the color uniformity of the concrete surface and have a special property - hydrophobicity. This hydrophobic layer can prevent free water in the concrete hydration stage from escaping through pores in the form of steam, ensuring sufficient moisture inside the concrete for hydration, thereby endowing the concrete with certain self-curing properties.

[0031] Antioxidants are used to inhibit the problem that the fatty acids containing double bonds in the above components are easily oxidized, resulting in the yellowing of the concrete after demolding.

[0032] The dispersing phase coagulation retardant component can regulate the freezing points of the oil phase and the emulsifier phase, preventing the crystallization of the oil phase or the oil-water interface film at low temperatures and reducing the emulsification stability.

[0033] Nano-titanium dioxide has stable chemical properties, high catalytic efficiency, and is non-toxic and harmless. In the emulsion, it can not only play the same role as kaolin in enhancing the strength of the oil-water interfacial film and improving the stability of the emulsion, but also play a role in adjusting the appearance color of concrete in engineering applications. Moreover, it can be used as a photocatalytic degradation catalyst for organic / microbial pollutants to inhibit the reduction of the aesthetics of the concrete appearance caused by pollutants and ultraviolet carbonization during service. Anatase titanium dioxide is more suitable for large-scale engineering fields due to its strong covering power, high coloring power, and relatively low price. Its refractive index is 2.55, which can effectively reflect and scatter ultraviolet rays. The nano-sized anatase titanium dioxide has a stronger ability to absorb ultraviolet rays, especially showing a significant absorption effect on ultraviolet rays in the medium-wave region.

[0034] The stable thixotropic component magnesium silicate has thickening and thixotropic properties, which can enhance viscosity and suspension, ensuring the stability of the emulsion at high temperatures. At the same time, the dried particles have lubricating properties, which can form a lubricating film at the interface between the mold and the cement product, significantly reducing the friction force. Due to its thixotropic property, it can provide a stable effect for the emulsion by increasing the system viscosity during the static storage stage of the emulsion. And during the application stage, since the original emulsion needs to be diluted for use, the viscosity of the emulsion can be reduced by stirring to improve the working performance of the emulsion application, making it more conducive to construction.

[0035] The second technical solution of the present invention is to provide a method for preparing the above-mentioned Pickering emulsion, including the following steps:

[0036] Emulsify the raw material components at 40 - 50 °C to obtain the Pickering emulsion.

[0037] The emulsification process adopted in the present invention is the water-in-oil method, and the preferred steps are:

[0038] (1) Stir and mix the base oil, composite emulsifier, co-emulsifier, pour point depressant component of the dispersed phase, antioxidant, and color regulator to obtain a mixture;

[0039] (2) Add water and the continuous phase thixotropic stabilizing component to the mixture obtained in step (1), and stir to obtain the Pickering emulsion.

[0040] More preferably, the stirring temperature in step (1) and step (2) is 40 - 50 °C; most preferably, the temperature in step (1) is 50 °C.

[0041] More preferably, step (1) is low-speed stirring, and step (2) is high-speed stirring.

[0042] The third technical solution of the present invention is to provide the application of the above-mentioned Pickering emulsion as a concrete release agent.

[0043] The present invention discloses the following technical effects:

[0044] The present invention provides a Pickering emulsion applied to concrete demoulding. Through the optimized proportioning of components such as base oil, composite emulsifier and co-emulsifier, it can effectively prevent concrete from adhering to the mold during the demoulding process, making the surface of the demoulded concrete smooth, uniform, with a uniform color and no color difference. This high-standard appearance not only enhances the visual effect of the product, but also improves the market competitiveness of concrete products, and is applicable to engineering projects with high aesthetic requirements.

[0045] In addition to excellent demoulding performance, the Pickering emulsion of the present invention also has excellent self-curing performance and anti-ultraviolet performance, which helps to promote the reasonable distribution and uniform curing of water inside the concrete, thereby improving the structural strength. At the same time, it can effectively resist ultraviolet damage, extend the service life of the concrete and maintain its appearance quality, and is particularly applicable to concrete structures exposed outdoors for a long time.

[0046] The present invention not only solves the problems existing in traditional demoulding agents, but also provides additional functionality and aesthetics for concrete products, is applicable to various building and infrastructure projects, and has broad application prospects. Detailed implementation manners

[0047] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and implementation schemes of the present invention.

[0048] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0049] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0050] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the description of the present invention, which are obvious to those skilled in the art. Other embodiments obtained from the description of the present invention are obvious to those skilled in the art. The description and examples of the present invention are merely exemplary.

[0051] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0052] In the following examples and comparative examples of the present invention, the titanium dioxide used is anatase titanium dioxide with an average particle size of 200 nm.

[0053] Example 1

[0054] The raw material mass ratio of the Pickering emulsion in this example is as follows:

[0055] 4010 naphthenic oil 200 parts, rapeseed oil 200 parts, composite emulsifier 60 parts (polyoxyethylene hydrogenated castor oil CO-40 17.5 parts, triglycerol monooleate 10 parts, decaglycerol monooleate 15 parts, sorbitan monooleate 7.5 parts, kaolin 10 parts), co-emulsifier 50 parts (25 parts lauric acid and 25 parts oleic acid), polymethacrylate T602HB 1.5 parts, dibutylhydroxytoluene 0.25 parts, butylhydroxyanisole 0.25 parts, titanium dioxide 10 parts, lithium magnesium silicate 10 parts, and deionized water 500 parts.

[0056] The preparation steps of the Pickering emulsion are as follows:

[0057] (1) Disperse and mix 4010 naphthenic oil, rapeseed oil, polyoxyethylene hydrogenated castor oil CO-40, triglycerol monooleate, decaglycerol monooleate, sorbitan monooleate, kaolin, lauric acid, oleic acid, polymethacrylate T602HB, dibutylhydroxytoluene, butylhydroxyanisole, and titanium dioxide at 50 °C at a high speed of 1000 rpm for 0.5 h;

[0058] (2) Adjust the stirring speed to 2000 rpm, and dropwise add deionized water to the mixture in step (1). The dropping time is controlled to be 1.5 h. After the dropping is completed, stir at 45 °C and 2000 rpm for 0.5 h;

[0059] (3) Add lithium magnesium silicate to the mixture obtained in step (2), and continue to stir at 45 °C and 2000 rpm for 1 h to obtain a milky homogeneous liquid, which is the Pickering emulsion.

[0060] Example 2

[0061] The mass parts ratio of the raw materials of the Pickering emulsion in this example is as follows:

[0062] 200 parts of naphthenic oil 4010, 200 parts of rapeseed oil, 50 parts of compound emulsifier (14 parts of polyoxyethylene hydrogenated castor oil CO-40, 8 parts of triglycerol monooleate, 12 parts of decaglycerol monooleate, 6 parts of sorbitan monooleate, 10 parts of kaolin), 60 parts of co-emulsifier (30 parts of n-decanoic acid and 30 parts of linoleic acid), 2 parts of polymethacrylate T602HB, 0.25 parts of dibutylhydroxytoluene, 0.25 parts of butylhydroxyanisole, 10 parts of titanium dioxide, 10 parts of magnesium aluminum silicate and 500 parts of deionized water.

[0063] The preparation steps of the Pickering emulsion are as follows:

[0064] (1) High-speed disperse and mix naphthenic oil 4010, rapeseed oil, polyoxyethylene hydrogenated castor oil CO-40, triglycerol monooleate, decaglycerol monooleate, sorbitan monooleate, kaolin, n-decanoic acid, linoleic acid, polymethacrylate T602HB, dibutylhydroxytoluene, butylhydroxyanisole and titanium dioxide at 50 °C at a speed of 1000 rpm for 0.5 h;

[0065] (2) Adjust the stirring speed to 2000 rpm, and add deionized water dropwise to the mixture in step (1). The dropping time is controlled to be 1.5 h. After the dropping is completed, stir at 40 °C and 2000 rpm for 0.5 h;

[0066] (3) Add magnesium aluminum silicate to the mixture obtained in step (2), and continue to stir at 40 °C and 2000 rpm for 1 h to obtain a milky homogeneous liquid, which is the Pickering emulsion.

[0067] Example 3

[0068] The mass parts ratio of the raw materials of the Pickering emulsion in this example is as follows:

[0069] 200 parts of naphthenic oil 4010, 200 parts of rapeseed oil, 50 parts of compound emulsifier (7 parts of polyoxyethylene hydrogenated castor oil CO-40, 4 parts of triglycerol monooleate, 13.5 parts of decaglycerol monooleate, 6.75 parts of sorbitan monooleate, 20 parts of kaolin), 60 parts of co-emulsifier (30 parts of n-decanoic acid and 30 parts of linoleic acid), 2 parts of polymethacrylate T602HB, 0.25 parts of dibutylhydroxytoluene, 0.25 parts of butylhydroxyanisole, 10 parts of titanium dioxide, 10 parts of magnesium aluminum silicate and 500 parts of deionized water.

[0070] The preparation steps of the Pickering emulsion are as follows:

[0071] (1) At 50 °C, disperse and mix naphthenic oil 4010, rapeseed oil, polyoxyethylene hydrogenated castor oil CO-40, triglycerol monooleate, decaglycerol monooleate, sorbitan monooleate, kaolin, n-decanoic acid, linoleic acid, polymethacrylate T602HB, dibutylhydroxytoluene, butylhydroxyanisole and titanium dioxide at a high speed of 1000 rpm for 0.5 h;

[0072] (2) Adjust the stirring speed to 2000 rpm, and add deionized water dropwise to the mixture in step (1). Control the dropping time to 1.5 h. After the dropping is completed, stir at 40 °C and 2000 rpm for 0.5 h;

[0073] (3) Add magnesium aluminum silicate to the mixture obtained in step (2), and continue to stir at 40 °C and 2000 rpm for 1 h to obtain a milky homogeneous liquid, which is the Pickering emulsion.

[0074] Example 4

[0075] The raw material mass ratio of the Pickering emulsion in this example is as follows:

[0076] 100 parts of naphthenic oil 4010, 300 parts of sunflower seed oil, 60 parts of compound emulsifier (19.6 parts of polyoxyethylene hydrogenated castor oil CO-40, 6.3 parts of triglycerol monooleate, 18.8 parts of decaglycerol monooleate, 5.3 parts of sorbitan monooleate, 10 parts of kaolin), 60 parts of co-emulsifier (30 parts of n-caprylic acid and 30 parts of linolenic acid), 1 part of polymethacrylate T602HB, 0.5 part of dibutylhydroxytoluene, 0.5 part of butylhydroxyanisole, 10 parts of titanium dioxide, 5 parts of lithium magnesium silicate, 5 parts of magnesium aluminum silicate and 550 parts of deionized water.

[0077] The preparation steps of the Pickering emulsion are as follows:

[0078] (1) At 50 °C, disperse and mix naphthenic oil 4010, sunflower seed oil, polyoxyethylene hydrogenated castor oil CO-40, triglycerol monooleate, decaglycerol monooleate, sorbitan monooleate, kaolin, n-caprylic acid, linolenic acid, polymethacrylate T602HB, dibutylhydroxytoluene, butylhydroxyanisole and titanium dioxide at a high speed of 1000 rpm for 0.5 h;

[0079] (2) Adjust the stirring speed to 2000 rpm, and add deionized water dropwise to the mixture in step (1). Control the dropping time to 1.5 h. After the dropping is completed, stir at 40 °C and 2000 rpm for 0.5 h;

[0080] (3) Add lithium magnesium silicate and aluminum magnesium silicate to the mixture obtained in step (2), and continue to stir at 40 °C and 2000 rpm for 1 h to obtain a milky homogeneous liquid, which is the Pickering emulsion.

[0081] Example 5

[0082] The parts by mass of the raw materials of the Pickering emulsion in this example are as follows:

[0083] 4010 naphthenic oil 100 parts, sunflower oil 300 parts, composite emulsifier 60 parts (polyoxyethylene hydrogenated castor oil CO-40 19.6 parts, triglycerol monooleate 6.3 parts, decaglycerol monooleate 18.8 parts, sorbitan monooleate 5.3 parts, kaolin 10 parts), 60 parts of co-emulsifier (30 parts of n-octanoic acid and 30 parts of linolenic acid), 1 part of polymethacrylate T602HB, 0.5 part of dibutylhydroxytoluene, 0.5 part of butylhydroxyanisole, 15 parts of titanium dioxide, 10 parts of lithium magnesium silicate and 550 parts of deionized water.

[0084] The preparation steps of the Pickering emulsion are as follows:

[0085] (1) High-speed disperse and mix 4010 naphthenic oil, sunflower oil, polyoxyethylene hydrogenated castor oil CO-40, triglycerol monooleate, decaglycerol monooleate, sorbitan monooleate, kaolin, n-octanoic acid, linolenic acid, polymethacrylate T602HB, dibutylhydroxytoluene, butylhydroxyanisole and titanium dioxide at 50 °C at a speed of 1000 rpm for 0.5 h;

[0086] (2) Adjust the stirring speed to 2000 rpm, add deionized water dropwise to the mixture in step (1), control the dropping time to 1.5 h, and after the dropping is completed, stir at 40 °C and 2000 rpm for 0.5 h;

[0087] (3) Add lithium magnesium silicate to the mixture obtained in step (2), and continue to stir at 40 °C and 2000 rpm for 1 h to obtain a milky homogeneous liquid, which is the Pickering emulsion.

[0088] Example 6

[0089] The parts by mass of the raw materials of the Pickering emulsion in this example are as follows:

[0090] 300 parts of naphthenic oil 4010, 100 parts of peanut oil, 60 parts of compound emulsifier (21 parts of polyoxyethylene hydrogenated castor oil CO-40, 7.5 parts of triglycerol monooleate, 7.5 parts of decaglycerol monooleate, 14 parts of sorbitan monooleate, 10 parts of kaolin), 60 parts of co-emulsifier (30 parts of n-caprylic acid and 30 parts of linolenic acid), 1 part of polymethacrylate T602HB, 0.5 part of dibutylhydroxytoluene, 0.5 part of butylhydroxyanisole, 15 parts of titanium dioxide, 8 parts of lithium magnesium silicate and 550 parts of deionized water.

[0091] The preparation steps of the Pickering emulsion are as follows:

[0092] (1) High-speed disperse and mix naphthenic oil 4010, peanut oil, polyoxyethylene hydrogenated castor oil CO-40, triglycerol monooleate, decaglycerol monooleate, sorbitan monooleate, kaolin, n-caprylic acid, linolenic acid, polymethacrylate T602HB, dibutylhydroxytoluene, butylhydroxyanisole and titanium dioxide at 50 °C at a speed of 1000 rpm for 0.5 h;

[0093] (2) Adjust the stirring speed to 2000 rpm, and add deionized water dropwise to the mixture in step (1). The dropping time is controlled to be 1.5 h. After the dropping is completed, stir at 40 °C and 2000 rpm for 0.5 h;

[0094] (3) Add lithium magnesium silicate to the mixture obtained in step (2), and continue to stir at 40 °C and 2000 rpm for 1 h to obtain a milky homogeneous liquid, which is the Pickering emulsion.

[0095] Comparative Example 1

[0096] A demoulding agent is prepared according to the preparation method described in Example 1 of the patent document CN 113717781 A "A water-in-oil-based concrete demoulding agent".

[0097] Comparative Example 2

[0098] This comparative example is the Jinhua Da Yipin EP-2 demoulding agent of Hunan Jinhua Da Building Materials Co., Ltd.

[0099] Comparative Example 3

[0100] This comparative example is the Ereducer®-201 concrete curing agent of Jiangsu Sobute New Materials Co., Ltd.

[0101] Comparative Example 4

[0102] A curing agent is prepared according to the preparation method described in Example 2 of the patent document CN113582720A "High water-retaining and ultraviolet-resistant concrete external curing agent and its preparation method".

[0103] Comparative Example 5

[0104] The parts by mass of the raw materials of the Pickering emulsion in this comparative example are as follows:

[0105] 300 parts of naphthenic oil 4010, 100 parts of peanut oil, 60 parts of composite emulsifier (28 parts of polyoxyethylene hydrogenated castor oil CO-40, 19 parts of sorbitan monooleate, 13 parts of kaolin), 60 parts of co-emulsifier (30 parts of n-octanoic acid and 30 parts of linolenic acid), 1 part of polymethacrylate T602HB, 0.5 part of dibutylhydroxytoluene, 0.5 part of butylhydroxyanisole, 15 parts of titanium dioxide, 8 parts of lithium magnesium silicate and 550 parts of deionized water.

[0106] The preparation steps of the Pickering emulsion are as follows:

[0107] (1) High-speed disperse and mix naphthenic oil 4010, peanut oil, polyoxyethylene hydrogenated castor oil CO-40, sorbitan monooleate, kaolin, n-octanoic acid, linolenic acid, polymethacrylate T602HB, dibutylhydroxytoluene, butylhydroxyanisole and titanium dioxide at 50 °C at a speed of 1000 rpm for 0.5 h;

[0108] (2) Adjust the stirring speed to 2000 rpm, and add deionized water dropwise to the mixture in step (1). The dropping time is controlled to be 1.5 h. After the dropping is completed, stir at 40 °C and 2000 rpm for 0.5 h;

[0109] (3) Add lithium magnesium silicate to the mixture obtained in step (2), and continue to stir at 40 °C and 2000 rpm for 1 h to obtain a milky homogeneous liquid, which is the Pickering emulsion.

[0110] Comparative Example 6

[0111] The parts by mass of the raw materials of the Pickering emulsion in this comparative example are as follows:

[0112] 300 parts of naphthenic oil 4010, 100 parts of peanut oil, 60 parts of composite emulsifier (21 parts of polyoxyethylene hydrogenated castor oil CO-40, 7.5 parts of triglycerol monooleate, 7.5 parts of decaglycerol monooleate, 14 parts of sorbitan monooleate, 10 parts of kaolin), 60 parts of co-emulsifier (30 parts of n-octanoic acid and 30 parts of linolenic acid), 1 part of polymethacrylate T602HB, 8 parts of lithium magnesium silicate and 550 parts of deionized water.

[0113] The preparation steps of the Pickering emulsion are as follows:

[0114] (1) High-speed disperse and mix naphthenic oil 4010, peanut oil, polyoxyethylene hydrogenated castor oil CO-40, polyglycerol monooleate, decaglycerol monooleate, sorbitan monooleate, kaolin, n-caprylic acid, linolenic acid, and polymethacrylate T602HB at 50 °C at a rotational speed of 1000 rpm for 0.5 h;

[0115] (2) Adjust the stirring speed to 2000 rpm, and add deionized water dropwise to the mixture in step (1). The dropping time is controlled to be 1.5 h. After the dropping is completed, stir at 40 °C and 2000 rpm for 0.5 h;

[0116] (3) Add lithium magnesium silicate to the mixture obtained in step (2), and continue to stir at 40 °C and 2000 rpm for 1 h to obtain a milky homogeneous liquid, which is the Pickering emulsion.

[0117] Verify the performance of the Pickering emulsion prepared in the examples of the present invention:

[0118] The tests were carried out in accordance with JC / T949-2005 "Release Agents for Concrete Products" to determine the storage stability, film-forming time, adhesion amount, demoulding performance, appearance of specimens after demoulding, and template corrosion of Examples 1-6 and Comparative Examples 1, 2, 5, and 6. The storage stability test of the examples and comparative examples was observed with the emulsion stock solution. For other tests, the samples were first diluted to a solid content of 15%, and the coating amount of the diluted solution on the template was controlled at 0.05 kg / m 2 The tests were carried out. The test environment was a temperature of 20 °C ± 5 °C and a relative humidity of 50% ± 10%. The results are shown in Table 1.

[0119] Table 1

[0120]

[0121] To verify the self-curing performance of the Pickering emulsion of the present invention, for the specimens demoulded with the Pickering emulsions of Examples 1-6 in the examples and the specimens coated with the external concrete curing agents of Comparative Examples 3-4, the effective water retention rate test was carried out with reference to the China Communications Industry Standard JT / T522-2004 "Concrete Curing Agents for Highway Engineering", and the surface rebound strength was tested to further verify the self-curing performance. The results are shown in Table 2.

[0122] The sun protection factor (SPF) indicates the level of sun protection efficacy of sun protection products. To prove the anti-ultraviolet performance of the Pickering emulsion of the present invention, the sun protection index of the Pickering emulsions in Examples 1-6 and the concrete external curing agents in Comparative Examples 3, 4, 5, and 6 was measured using an SPF-290S type sun protection index (SPF) tester. The specific method was as follows: Use a syringe to extract 1 mL of the sample emulsion with a solid content of 15%, and evenly coat it on the special adhesive tape. After the sample was coated, it was left for 30 min, and then the sun protection factor of the sample was tested according to the test method of the SPF-290S type sun protection index (SPF) tester. The specific results are shown in Table 2.

[0123] Table 2

[0124]

[0125] Through the test according to the standard of JC / T949-2005 "Release Agent for Concrete Products", it can be proved that the Pickering emulsion of the present invention has excellent basic demoulding performance. The concrete demoulded using the present invention has a high-standard appearance with a smooth surface, uniform color, and no color difference. In addition, through the effective water retention rate of JT / T522-2004 "Concrete Curing Agent for Highway Engineering", it is proved that the concrete test group demoulded using the present invention can reach the water retention standard of applying a qualified curing agent without applying a curing agent, and the surface rebound test further proves the self-curing performance of the present invention. In addition, the SPF test results show that the concrete test group demoulded using the present invention has excellent anti-ultraviolet performance.

[0126] The above-described embodiments are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A Pickering emulsion, characterized in that The invention comprises the following raw material components in parts by weight: 200-600 parts of base oil, 50-60 parts of composite emulsifier, 50-60 parts of auxiliary emulsifier, 1-2 parts of dispersed phase pour point depressant component, 0.5-1 part of antioxidant, 8-10 parts of continuous phase thixotropic stabilizing component, 10-15 parts of color regulator and 500-550 parts of water; The base oil includes mineral oil and vegetable oil; The composite emulsifier comprises polyoxyethylene hydrogenated castor oil CO-40, triglycerol monooleate, decaglycerol monooleate, sorbitan monooleate and kaolin; The auxiliary emulsifier includes one or a combination of two of a medium-chain saturated fatty acid having 8 to 12 carbon atoms in the carbon chain and an unsaturated fatty acid having 18 carbon atoms; The dispersed phase pour point depressing component includes polymethacrylate T602HB; The antioxidant includes one or a combination of butylated hydroxytoluene and butylated hydroxyanisole; The continuous phase thixotropic stabilizing component includes one or a combination of magnesium aluminum silicate and magnesium lithium silicate.

2. The Pickering emulsion according to claim 1, characterized in that The mineral oil is naphthenic oil.

3. The Pickering emulsion according to claim 2, characterized in that The cyclopentane oil is cyclopentane oil 4010.

4. The Pickering emulsion according to claim 1, characterized in that The vegetable oil includes one or a combination of two or more of rapeseed oil, sunflower seed oil and peanut oil.

5. The Pickering emulsion according to claim 1, characterized in that The medium-chain saturated fatty acid with 8-12 carbon atoms on the carbon chain includes one or more of caprylic acid, capric acid or lauric acid; the unsaturated fatty acid with 18 carbon atoms is one or more of oleic acid, linoleic acid or linolenic acid.

6. The Pickering emulsion according to claim 1, characterized in that The antioxidant is a complex of butylated hydroxytoluene and butylated hydroxyanisole in a mass ratio of 1:

1.

7. The Pickering emulsion according to claim 1, characterized in that The color modifier includes titanium dioxide.

8. The Pickering emulsion according to claim 7, characterized in that The titanium dioxide is anatase titanium dioxide.

9. The method for preparing the Pickering emulsion according to any one of claims 1 to 8, characterized in that: The following steps are involved: The raw material components are emulsified at 40-50° C. to obtain the Pickering emulsion.

10. Use of the Pickering emulsion according to any one of claims 1 to 8 as a concrete release agent.

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