Pickering emulsion applied to concrete demolding and preparation method of Pickering emulsion

Abstract

The invention discloses Pickering emulsion applied to concrete demolding and a preparation method thereof, and relates to the technical field of building materials. The Pickering emulsion is prepared from the following raw material components: 200 to 600 parts of base oil, 50 to 60 parts of a compound emulsifier, 50 to 60 parts of a co-emulsifier, 1 to 2 parts of a dispersed phase pour point depressing component, 0.5 to 1 part of an antioxidant, 8 to 10 parts of a continuous phase thixotropic stabilizing component, 10 to 15 parts of a color regulating agent and 500 to 550 parts of water. The Pickering emulsion has excellent concrete demoulding performance, also has concrete self-curing performance and anti-ultraviolet performance, and can effectively improve the structural strength of concrete, prolong the service life of concrete and ensure the appearance quality of concrete. The problems existing in a traditional release agent are solved, additional functionality and attractiveness are provided for concrete products, and the release agent is suitable for various building and infrastructure projects and has wide application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of building materials, in particular to a Pickering emulsion used 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. In order to ensure that concrete has excellent appearance quality, the following key factors must be considered comprehensively: raw material selection, slump control, construction technology (especially pouring and vibration), formwork type and surface treatment, and the type and quality of release agent.

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

[0004] In actual engineering applications, release agents are usually applied to the surface of steel molds or other materials by brushing or spraying before concrete pouring to ensure smooth demoulding of concrete and achieve the desired appearance. Choosing the right release agent is crucial to achieving high-quality concrete appearance.

[0005] At present, many engineering projects require release agents not only to meet the requirements of non-sticking during the demoulding stage, but also to set higher standards for the appearance of concrete. The ideal concrete surface should be smooth and clean, with small and small bubbles, no sand lines and water marks, and uniform color. Some projects even require the appearance of concrete to reach a specific light gray standard color. However, most release agents on the market are difficult to meet these improvement requirements at the same time. Especially for emulsion release agents, due to their thermodynamic instability, demulsification and stratification are prone to occur during storage, thus affecting the demoulding effect.

[0006] Studies have shown that solid particles (such as silica, carbon black, iron oxide and clay) can form a spatial distribution in the oil-water mixture system and adsorb on the interface of the oil-water droplets to form a thin and elastic particle layer. This layer of particles effectively prevents the droplets from coalescing and gives the emulsion long-term dynamic stability. The emulsion prepared by introducing solid particles is called Pickering emulsion. Although Pickering emulsion has been widely used in food, cosmetics, pharmaceutical and petroleum industries, there is still little research and application in the field of concrete. Summary of the invention

[0007] The purpose of the present invention is to provide a Pickering emulsion for 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 give concrete self-curing and anti-ultraviolet properties, significantly improving the quality and durability of concrete parts.

[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, comprising the following raw material components in parts by weight:

[0010] 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.

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

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

[0013] The composite emulsifier comprises polyoxyethylene hydrogenated castor oil CO-40, triglycerol monooleate, decaglycerol monooleate, sorbitan monooleate and kaolin.

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

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

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

[0017] The antioxidant includes one of butylated hydroxytoluene and butylated hydroxyanisole or a combination of both.

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

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

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

[0021] As a further preferred embodiment 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 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.

[0023] As a further preferred embodiment of the present invention, the antioxidant is a complex of butylated hydroxytoluene and butylated hydroxyanisole in a mass ratio of 1:1.

[0024] As a further preferred embodiment of the present invention, the color regulator comprises titanium dioxide.

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

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

[0027] The selection of emulsifiers in the preparation of the Pickering emulsion of the present invention is not a simple compounding, but a calculation selection based on the HLB emulsification method, which is to prepare a stable emulsion by selecting an emulsifier with a suitable HLB value. The HLB value (hydrophilic-hydrophobic balance value) is used to indicate the balance between the hydrophilicity and lipophilicity of a surfactant. The larger the value, the stronger the hydrophilicity, and the smaller the value, the stronger the lipophilicity. The selection principles of HLB value include three items: 1. Determine the HLB value required for the emulsification system: select the appropriate HLB value according to the properties of the emulsification system (such as water-in-oil or oil-in-water). The HLB value of O / W (water-in-oil) emulsion is usually between 8 and 18, and the HLB value of W / O (oil-in-water) emulsion is usually between 3 and 6. The emulsion prepared in the present invention is O / W (water-in-oil) emulsion; 2. Determine the HLB value required for base oil emulsification, such as the HLB value required for alkane mineral oil W / O emulsion is 4, and the HLB value required for O / W emulsion is 10. For example, the HLB value required for aromatic mineral oil W / O emulsion is 4, and the HLB value required for O / W emulsion is 12. The HLB range required for the combined base oil water-in-oil emulsion of the present invention is 11-13; 3. Select the best emulsification System: When choosing an emulsification system, you can choose a single emulsifier or a composite emulsifier, but a single emulsifier emulsification system has the following key defects: (a) Poor stability: A single emulsifier has poor stability, low interaction force at the oil-water interface, low arrangement density, and is easy to demulsify; (b) Performance limitations: The function of a single emulsifier is relatively single, and it is difficult to meet a variety of emulsification requirements. Low HLB emulsifiers can only prepare oil-in-water emulsions, and high HLB emulsifiers can only prepare water-in-oil emulsions. In addition, the premise for preparing a stable emulsion is that the HLB value of the emulsifier completely corresponds to the HLB value required by the base oil it emulsifies, which makes it more difficult; (c) Difficult to adjust: The HLB value (hydrophile-lipophile balance) of a single emulsifier is fixed and difficult to adjust, and cannot adapt to different emulsification requirements. Therefore, in order to address the above defects, emulsion preparation usually selects a pair of emulsifiers with a large difference in HLB values ​​and mixes them in different proportions to test the HLB value that is most suitable 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 forces at the oil-water interface and provide a tighter arrangement, so that the stability of the emulsion is further improved. When using a composite emulsifier, the best combination can be determined by calculating the mixed HLB value. When the HLB value required for the composite emulsifier and the base oil emulsification is the same, a relatively stable emulsion 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 Respectively represent the HLB value of each surfactant and its mass proportion in the mixture.

[0028] The present invention is based on the above two types of base oils. By rationally compounding different types of emulsifiers, a more perfect molecular membrane structure can be formed during the emulsification process to enhance the stability of the emulsified system. Different types of emulsifiers differ in interfacial activity and molecular configuration. Compounding can give full play to the characteristics of each emulsifier and improve the stability of the emulsified system. Triglycerol monooleate and decaglycerol monooleate are both polymers obtained by esterification of glycerol and monooleic anhydride. This substance has the characteristics of a non-ionic alkoxylated multifunctional emulsifier. Triglycerol monooleate (C 27 H 52 O8) has an HLB of 7-8 and a molecular weight of 504.7. 36 H 70 O 14 ) has an HLB of 13.5-14 and a molecular weight of 726.9. The two have high compatibility when used as composite emulsifiers due to their similar structures. The large HLB difference has a flexible regulatory effect on different base oils. The difference in molecular weight can further supplement the vacancies of small molecules on the basis of macromolecules inserting into the oil-water interface, thereby increasing the density of the molecular arrangement of the interface film. The main component of polyoxyethylene hydrogenated castor oil is the hydrophobic component polyoxyethylene glycerol trihydroxystearate. It also contains a small amount of hydrophobic component polyethylene glycol trihydroxystearate and unreacted castor oil, as well as 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 Span80 is a nonionic surfactant, which is obtained by esterification of sorbitol and oleic acid. Span80 is hydrophobic and can only be used as an oil-in-water emulsifier when used alone. Its HLB value is 4.3 and its molecular weight is 429. The hydrophilic part (dehydrated sorbitol) and the hydrophobic part (oleate) in its molecular structure give it the characteristics of a surfactant. The same method of use as the two polyglycerol monooleates is used. Span80 also needs to be compounded with a high HLB value emulsifier to prepare water-in-oil emulsions of base oils with different required HLB values ​​(the present invention uses polyoxyethylene hydrogenated castor oil in combination with it). A smaller molecular weight can further enhance the tight arrangement of the oil-water interface film.

[0029] More preferably, it has been proposed above that kaolin can form a spatial distribution in the oil-water mixed system and adsorb on the interface of the oil-water droplets to form a thin and elastic particle layer. This layer of particles effectively prevents the droplets from coalescing and gives the emulsion long-term dynamic stability. Since kaolin itself is not dispersed in both the aqueous phase and the oil phase, the non-ionic surfactant sorbitan monooleate is used to modify kaolin in situ, and the hydrogen bonds between the hydrophilic groups of the sorbitan monooleate molecules are adsorbed on the hydrophilic surface of kaolin, and the hydrophobic tail is exposed away from the surface, so that the surface of the kaolin particles is effectively hydrophobic and induces a steric effect, so that it can be used as a new surfactant to increase the arrangement density and strength of the oil-water interface. However, it should be noted that after Span80 is mixed with it, it is only surface-modified, and the total amount of hydrophobic groups in the mixture is not changed relative 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 oil-in-water emulsions when used alone. In addition, when the emulsion is applied to the template surface to form a film, kaolin is also evenly dispersed and exposed in the template. Due to its high specific surface area and good dispersibility, it forms a uniform film on the mold surface, thereby reducing the friction between the mold and the molding material and promoting demolding. In addition, the high temperature resistance of kaolin also enables it to perform well in the high temperature curing molding process, further improving the demolding effect.

[0030] Co-emulsifiers are all low molecular weight straight chain fatty acids. This type of fatty acid can be inserted into the vacancies of the molecular arrangement of the emulsifier at the oil-water interface to form a denser arrangement, thereby reducing the particle size of the dispersed phase and improving the stability of the emulsion. The reason why it is defined as a co-emulsifier is that although its addition can improve the stability of the emulsion, it will not affect the HLB value required for the emulsification of the emulsion. In addition, this type of fatty acid is similar to vegetable oil, but it does not need to be hydrolyzed and directly reacts with calcium ions or calcium salts (such as calcium hydroxide, calcium carbonate, and calcium sulfate) in cement to generate fatty acid calcium, and the aluminum ions and fatty acid root ions in the concrete system will also react to generate fatty acid aluminum, which is arranged in a directional manner on the concrete surface. The above two products can improve the color uniformity of the concrete surface and have a special property-hydrophobicity. This hydrophobic layer can prevent free water from escaping through the pores in the form of steam during the hydration stage of the concrete, ensuring that there is sufficient water inside the concrete for hydration, thereby giving the concrete a certain self-curing performance.

[0031] Antioxidants are used to inhibit the yellowing of concrete after demoulding due to the fatty acids containing double bonds in the above components being easily oxidized.

[0032] The pour point depressant component of the dispersed phase can regulate the pour point of the oil phase and the emulsifier phase, preventing the oil phase or the oil-water interface film from crystallizing under low temperature conditions and reducing the emulsification stability.

[0033] Nano titanium dioxide has stable chemical properties, high catalytic efficiency, and is non-toxic and harmless. In emulsion, it can not only play the same role as kaolin in improving the strength of the oil-water interface film and the stability of the emulsion, but also adjust the color of the concrete appearance in engineering applications. It can also be used as a photodegradation catalyst for organic / microbial pollutants to inhibit the appearance of concrete from being degraded due to pollutants and ultraviolet carbonization during service. Anatase titanium dioxide is more commonly used in large-volume engineering fields due to its strong hiding power, high tinting power and relatively low price. Its refractive index is 2.55, which can effectively reflect and scatter ultraviolet rays. Nano-sized anatase titanium dioxide has a stronger ability to absorb ultraviolet rays, especially the absorption effect of 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 that the emulsion remains stable at high temperatures. At the same time, its dried particles have lubricating properties and can form a lubricating film at the interface between the mold and the cement part, significantly reducing friction. Because of its thixotropic properties, it can provide a stabilizing effect for the emulsion by increasing the viscosity of the system during the static storage stage of the emulsion. In the application stage, the original emulsion needs to be diluted for use, so stirring can reduce the viscosity of the emulsion and 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 Pickering emulsion, comprising the following steps:

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

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

[0038] (1) stirring and mixing a base oil, a composite emulsifier, an emulsifier co-emulsifier, a dispersed phase pour point depressant component, an antioxidant and a color control agent to obtain a mixture;

[0039] (2) Add water and a continuous phase thixotropic stabilizing component to the mixture obtained in step (1), and stir to obtain a 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 use 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 for concrete demoulding. By optimizing the proportion of components such as base oil, composite emulsifier and co-emulsifier, the concrete can be effectively prevented from adhering to the mold during the demoulding process, so that the surface of the demoulded concrete is smooth and uniform, and the color is uniform and has 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. The emulsion is suitable for engineering projects with high requirements for aesthetics.

[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 of moisture inside the concrete and uniform curing, thereby improving the structural strength. At the same time, it can effectively resist ultraviolet damage, extend the service life of concrete and maintain its appearance quality, and is particularly suitable for concrete structures exposed outdoors for a long time.

[0046] The present invention not only solves the problems existing in traditional release agents, but also provides additional functionality and aesthetics for concrete products, is suitable for various construction and infrastructure projects, and has broad application prospects. DETAILED DESCRIPTION

[0047] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0048] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0049] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may 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 associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0050] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0051] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

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

[0053] Example 1

[0054] The raw material mass proportions of the Pickering emulsion in this embodiment are as follows:

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

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

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

[0058] (2) adjusting the stirring speed to 2000 rpm, adding deionized water to the mixture of step (1) dropwise for 1.5 h. After the addition, stirring 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 stirring at 45° C. and 2000 rpm for 1 h to obtain a milky white homogeneous liquid, namely, the Pickering emulsion.

[0060] Example 2

[0061] The raw material mass proportions of the Pickering emulsion in this embodiment are as follows:

[0062] 200 parts of cyclohexane oil 4010, 200 parts of rapeseed oil, 50 parts of composite 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 auxiliary emulsifier (30 parts of n-decanoic acid and 30 parts of linoleic acid), 2 parts of polymethacrylate T602HB, 0.25 parts of butylated hydroxytoluene, 0.25 parts of butylated hydroxyanisole, 10 parts of titanium dioxide, 10 parts of magnesium aluminum silicate and 500 parts of deionized water.

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

[0064] (1) 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, butylated hydroxytoluene, butylated hydroxyanisole and titanium dioxide were dispersed and mixed at a high speed of 1000 rpm at 50° C. for 0.5 h;

[0065] (2) adjusting the stirring speed to 2000 rpm, adding deionized water to the mixture of step (1) dropwise for 1.5 h. After the addition, stirring at 40 ° C and 2000 rpm for 0.5 h;

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

[0067] Example 3

[0068] The raw material mass proportions of the Pickering emulsion in this embodiment are as follows:

[0069] 200 parts of cyclohexane oil 4010, 200 parts of rapeseed oil, 50 parts of composite 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 auxiliary emulsifier (30 parts of n-decanoic acid and 30 parts of linoleic acid), 2 parts of polymethacrylate T602HB, 0.25 parts of butylated hydroxytoluene, 0.25 parts of butylated hydroxyanisole, 10 parts of titanium dioxide, 10 parts of magnesium aluminum silicate and 500 parts of deionized water.

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

[0071] (1) 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, butylated hydroxytoluene, butylated hydroxyanisole and titanium dioxide were dispersed and mixed at a high speed of 1000 rpm at 50° C. for 0.5 h;

[0072] (2) adjusting the stirring speed to 2000 rpm, adding deionized water to the mixture of step (1) dropwise for 1.5 h. After the addition, stirring at 40 ° C and 2000 rpm for 0.5 h;

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

[0074] Example 4

[0075] The raw material mass proportions of the Pickering emulsion in this embodiment are as follows:

[0076] 100 parts of cyclohexane oil 4010, 300 parts of sunflower oil, 60 parts of composite 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 auxiliary emulsifier (30 parts of n-octanoic acid and 30 parts of linolenic acid), 1 part of polymethacrylate T602HB, 0.5 parts of butylated hydroxytoluene, 0.5 parts of butylated hydroxyanisole, 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 Pickering emulsion are as follows:

[0078] (1) naphthenic oil 4010, sunflower oil, polyoxyethylene hydrogenated castor oil CO-40, triglycerol monooleate, decaglycerol monooleate, sorbitan monooleate, kaolin, n-octanoic acid, linolenic acid, polymethacrylate T602HB, butylated hydroxytoluene, butylated hydroxyanisole and titanium dioxide were dispersed and mixed at a high speed of 1000 rpm at 50°C for 0.5 h;

[0079] (2) adjusting the stirring speed to 2000 rpm, adding deionized water to the mixture of step (1) dropwise for 1.5 h. After the addition, stirring 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 stirring at 40° C. and 2000 rpm for 1 h to obtain a milky white homogeneous liquid, which is the Pickering emulsion.

[0081] Example 5

[0082] The raw material mass proportions of the Pickering emulsion in this embodiment are as follows:

[0083] 100 parts of cyclohexane oil 4010, 300 parts of sunflower oil, 60 parts of composite 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 auxiliary emulsifier (30 parts of n-octanoic acid and 30 parts of linolenic acid), 1 part of polymethacrylate T602HB, 0.5 parts of butylated hydroxytoluene, 0.5 parts of butylated hydroxyanisole, 15 parts of titanium dioxide, 10 parts of lithium magnesium silicate and 550 parts of deionized water.

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

[0085] (1) naphthenic oil 4010, sunflower oil, polyoxyethylene hydrogenated castor oil CO-40, triglycerol monooleate, decaglycerol monooleate, sorbitan monooleate, kaolin, n-octanoic acid, linolenic acid, polymethacrylate T602HB, butylated hydroxytoluene, butylated hydroxyanisole and titanium dioxide were dispersed and mixed at a high speed of 1000 rpm at 50°C for 0.5 h;

[0086] (2) adjusting the stirring speed to 2000 rpm, adding deionized water to the mixture of step (1) dropwise for 1.5 h. After the addition, stirring 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 stirring at 40° C. and 2000 rpm for 1 h to obtain a milky white homogeneous liquid, namely, the Pickering emulsion.

[0088] Example 6

[0089] The raw material mass proportions of the Pickering emulsion in this embodiment are as follows:

[0090] 300 parts of cyclohexane oil 4010, 100 parts of peanut oil, 60 parts of composite emulsifier (1 part of polyoxyethylene hydrogenated castor oil CO-402, 7.5 parts of triglycerol monooleate, 7.5 parts of decaglycerol monooleate, 14 parts of sorbitan monooleate, 10 parts of kaolin), 60 parts of auxiliary emulsifier (30 parts of n-octanoic acid and 30 parts of linolenic acid), 1 part of polymethacrylate T602HB, 0.5 parts of butylated hydroxytoluene, 0.5 parts of butylated hydroxyanisole, 15 parts of titanium dioxide, 8 parts of lithium magnesium silicate and 550 parts of deionized water.

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

[0092] (1) naphthenic oil 4010, peanut oil, polyoxyethylene hydrogenated castor oil CO-40, triglycerol monooleate, decaglycerol monooleate, sorbitan monooleate, kaolin, n-octanoic acid, linolenic acid, polymethacrylate T602HB, butylated hydroxytoluene, butylated hydroxyanisole and titanium dioxide were dispersed and mixed at a high speed of 1000 rpm at 50°C for 0.5 h;

[0093] (2) adjusting the stirring speed to 2000 rpm, adding deionized water to the mixture of step (1) dropwise for 1.5 h. After the addition, stirring 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 stirring at 40° C. and 2000 rpm for 1 h to obtain a milky white homogeneous liquid, namely, the Pickering emulsion.

[0095] Comparative Example 1

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

[0097] Comparative Example 2

[0098] This comparative example is the Jinhuada Yipin EP-2 mold release agent produced by Hunan Jinhuada Building Materials Co., Ltd.

[0099] Comparative Example 3

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

[0101] Comparative Example 4

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

[0103] Comparative Example 5

[0104] The raw material mass proportions of the Pickering emulsion in this comparative example are as follows:

[0105] 300 parts of cyclohexane 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 auxiliary emulsifier (30 parts of n-octanoic acid and 30 parts of linolenic acid), 1 part of polymethacrylate T602HB, 0.5 parts of butylated hydroxytoluene, 0.5 parts of butylated hydroxyanisole, 15 parts of titanium dioxide, 8 parts of lithium magnesium silicate and 550 parts of deionized water.

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

[0107] (1) naphthenic oil 4010, peanut oil, polyoxyethylene hydrogenated castor oil CO-40, sorbitan monooleate, kaolin, n-octanoic acid, linolenic acid, polymethacrylate T602HB, butylated hydroxytoluene, butylated hydroxyanisole and titanium dioxide were dispersed and mixed at a high speed of 1000 rpm at 50°C for 0.5 h;

[0108] (2) adjusting the stirring speed to 2000 rpm, adding deionized water to the mixture of step (1) dropwise for 1.5 h. After the addition, stirring 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 stirring at 40° C. and 2000 rpm for 1 h to obtain a milky white homogeneous liquid, namely, the Pickering emulsion.

[0110] Comparative Example 6

[0111] The raw material mass proportions of the Pickering emulsion in this comparative example are as follows:

[0112] 300 parts of cyclohexane 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 auxiliary 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 Pickering emulsion are as follows:

[0114] (1) naphthenic oil 4010, peanut oil, polyoxyethylene hydrogenated castor oil CO-40, triglycerol monooleate, decaglycerol monooleate, sorbitan monooleate, kaolin, n-octanoic acid, linolenic acid, and polymethacrylate T602HB were dispersed and mixed at a high speed of 1000 rpm at 50°C for 0.5 h;

[0115] (2) adjusting the stirring speed to 2000 rpm, adding deionized water to the mixture of step (1) dropwise for 1.5 h. After the addition, stirring 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 stirring at 40° C. and 2000 rpm for 1 h to obtain a milky white homogeneous liquid, namely, the Pickering emulsion.

[0117] The performance of the Pickering emulsion prepared in the embodiment of the present invention was verified:

[0118] The test was conducted in accordance with JC / T949-2005 "Release Agents for Concrete Products" to determine the storage stability, film forming time, adhesion, demoulding performance, appearance of the specimens after demoulding, and formwork 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 using the original emulsion. For other tests, the samples were first diluted to 15% solid content, and the amount of the diluent applied to the formwork was controlled at 0.05 kg / m 2 The test was carried out in an environment with 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] In order to verify the self-curing performance of the Pickering emulsion of the present invention, the effective water retention rate of the test pieces demoulded with the Pickering emulsion of Examples 1-6 and the test pieces coated with the concrete external curing agent of Comparative Examples 3-4 were tested with reference to the Chinese transportation industry standard JT / T522-2004 "Concrete Curing Agent 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) is the degree of sun protection effect of sunscreen products. In order to prove the anti-ultraviolet performance of the Pickering emulsion of the present invention, the Pickering emulsions of Examples 1-6 and the concrete curing agents of Comparative Examples 3, 4, 5, and 6 were tested for the sun protection factor of the emulsion using an SPF-290S sun protection factor (SPF) tester. The specific method is to use a syringe to extract 1 mL of a sample emulsion with a solid content of 15%, and evenly apply a film on a special tape. After the sample is coated, place it for 30 minutes, and test the sun protection factor of the sample according to the test method of the SPF-290S sun protection factor (SPF) tester. The specific results are shown in Table 2.

[0123] Table 2

[0124]

[0125] The test of JC / T949-2005 "Release Agent for Concrete Products" standard proves that the Pickering emulsion of the present invention has excellent basic demoulding performance, and the concrete demoulded by the present invention has a high standard appearance with smooth surface, uniform color, and no color difference. In addition, the effective water retention rate of JT / T522-2004 "Concrete Curing Agent for Highway Engineering" proves that the concrete test group demoulded by the present invention can reach the water retention standard of the curing agent applied with qualified products without applying the 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 by the present invention has excellent UV resistance.

[0126] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all 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.

Images