Aluminum template interface agent and preparation method thereof

Abstract

The present application relates to the field of building materials technology, and specifically discloses a kind of aluminum template interface agent and its preparation method. A kind of aluminum template interface agent includes the following weight parts of raw materials: 10-12 parts of polyvinyl alcohol, 4-6 parts of modified nano-silica, 4-6 parts of organic bentonite, 8-11 parts of terephthalic acid monoamide, 7-10 parts of oily additives, 5-9 parts of fatty acid soap, 0.5-1 parts of pH regulator, and the modified nano-silica is nano-silica modified by amide group; Its preparation method is: after base oil, fatty acid soap and terephthalic acid monoamide are mixed, heating and stirring reaction is carried out to obtain a mixed solution; Modified nano-silica is added to the heated mixed solution, after stirring evenly, organic bentonite is continued to be added to react with polyvinyl alcohol, pH regulator is added, and stirring evenly is obtained. The composition of the present application can be used for aluminum template surface demoulding, has excellent demoulding effect, and there are almost no bubbles on the concrete surface after use, which effectively prevents heat loss from the concrete surface.

Description

Technical Field

[0001] The present application relates to the technical field of building materials, and more specifically, to an aluminum template interface agent and a preparation method thereof. Background Art

[0002] Concrete is the most common building material and is widely used in construction, infrastructure and engineering projects. It is a mixture of ingredients such as cement, sand, aggregate and water. After curing, it forms a strong structure. In its preparation process, demoulding is a key step.

[0003] As a common concrete demoulding material, aluminum formwork has the advantages of light weight, strong bearing capacity, high turnover rate, and easy installation and disassembly compared to other traditional formwork materials. Aluminum formwork has a longer service life and can be reused many times. It is widely used in the construction of modern high-rise buildings.

[0004] However, compared to traditional wooden formwork materials, aluminum formwork has a smoother surface and is less absorbent. This allows bubbles to accumulate on the surface after vibration. Concrete is alkaline, and the chemical reaction between aluminum and alkaline solutions produces hydrogen. This gas can attach to the aluminum formwork surface, forming bubbles, causing spots, unevenness, and uneven coloring on the concrete surface, which in turn affects the appearance and quality of the concrete. The use of a release agent can effectively reduce the adhesion between the concrete and the formwork, significantly reducing the number of pores on the concrete surface. This facilitates demolding, maintains the surface integrity of the concrete, and protects the aluminum formwork from rust. This significantly reduces or even eliminates surface quality issues on concrete products, ensuring both appearance and quality. However, aluminum formwork's superior thermal conductivity can cause the concrete to dissipate its hydration heat more quickly in contact with the aluminum formwork, while dissipating more slowly within the concrete. This temperature difference between the inside and outside of the concrete can lead to cracks in the concrete. Summary of the Invention

[0005] In order to improve the demoulding effect of the aluminum formwork interface agent and avoid damage and defects of concrete, the present application provides an aluminum formwork interface agent and a preparation method thereof.

[0006] In the first aspect, the present application provides an aluminum template interface agent, which adopts the following technical solution:

[0007] An aluminum template interface agent comprises the following raw materials in parts by weight:

[0008] 10-12 parts of polyvinyl alcohol, 4-6 parts of modified nano-silica, 4-6 parts of organic bentonite, 8-11 parts of terephthalic acid monoamide, 7-10 parts of oily additives, 5-9 parts of fatty acid soap, and 0.5-1 part of pH regulator. The modified nano-silica is nano-silica modified with an amide group.

[0009] By adopting the above technical solution, nano-silica has high thermal resistance and is added after modification, so it has good dispersibility, which is conducive to the uniform coverage of the interface agent on the surface of the aluminum formwork. Ingredients such as polyvinyl alcohol, organic bentonite and fatty acid soap have lubricating properties, which can not only reduce the friction and adhesion between the aluminum formwork and the concrete, but also help reduce the wear and damage of the formwork and increase the service life of the aluminum formwork. In addition, the network structure constructed by polyvinyl alcohol and amide groups confines the heat-insulating nano-silica and organic bentonite therein, further improving the heat-insulating capacity of the interface agent and preventing the concrete from cracking due to the large temperature difference between the inside and the outside due to the rapid heat dissipation of the concrete close to the aluminum formwork.

[0010] Polyvinyl alcohol has good film-forming properties, and the presence of terephthalic acid monoamide allows hydrogen bonds to form between the fatty acid soap and the base oil. During the preparation of the interface agent, the amide molecules form a fine fiber structure, which then aggregates to form coarse fibers and associates with each other, forming a tight, stable fiber skeleton spatial network structure, which allows the soap molecules to adhere to it. The resulting interface agent can withstand high shear stress. At the same time, the strong polarity of the amide group can form an induced dipole between the interface agent and the surface of the aluminum formwork. Combined with its own permanent dipole, it forms a strong adsorption. The intermolecular hydrogen bonds form a dense protective film on the side of the interface agent closest to the concrete, ensuring the smoothness and integrity of the concrete surface and achieving good demolding effect. Organic bentonite can form a gel in oily solvents. Its addition helps further prevent the sedimentation of modified silica, has good film-forming properties, ensures film-forming performance, effectively prevents cracking and damage in the interface agent, reduces the formation of interfacial pores, and significantly reduces the number of bubbles on the concrete surface after demolding.

[0011] Optionally, the modified nano-silica is prepared by the following method:

[0012] (1) adding nano-silica to a mixed solution 1 to carry out a hydrothermal reaction, followed by washing and drying to obtain alkalized nano-silica, wherein the alkaline mixed solution contains sodium hydroxide, hydrogen peroxide and deionized water;

[0013] (2) The alkalized silica is added to the mixed solution 2, and the air in the reaction bottle is removed by inert gas to react. After the reaction is completed, the amide group-modified nano-silica is obtained by washing and drying. The mixed solution 2 is a mixture of an acylating agent, dimethylformamide and deionized water.

[0014] By adopting the above technical solution, nano-silica has high thermal resistance, but its dispersibility in oily solvents is poor. Since silica has a large specific surface area and high surface energy, particles are prone to aggregation and sedimentation, resulting in poor dispersion in the interface agent and a decline in the performance of the interface agent. By introducing amide groups after alkaline treatment of the nano-silica, on the one hand, the amide groups form hydrogen bonds with solvent molecules through the interaction of intermolecular van der Waals forces, thereby reducing the interaction between particles, preventing particle aggregation and sedimentation, improving the dispersibility of silica in the interface agent, and improving the stability of the interface agent; on the other hand, the nano-silica with amide groups improves the thermal insulation performance of the interface agent, preventing the problem of concrete cracking caused by rapid heat dissipation.

[0015] Optionally, in step (1), the mass ratio of sodium hydroxide, hydrogen peroxide and deionized water in the mixed solution 1 is 1:1:(1-1.5).

[0016] By adopting the above technical solution, sodium hydroxide and hydrogen peroxide are mixed to introduce hydroxyl functional groups to the surface of nano-silica, thereby improving the surface activity of nano-silica, providing more active sites for the subsequent access of amide groups, and ensuring the access rate of amide groups.

[0017] Optionally, the mass ratio of the alkalized silica to the mixed solution 2 in step (2) is (1.6-3.2):1, and the mass ratio of the acylating agent, 3-aminopropyltriethoxysilane and deionized water in the mixed solution 2 is (0.8-1):(1-2):2.

[0018] By adopting the above technical solution, the amino groups in 3-aminopropyltriethoxysilane react with the hydroxyl groups on the surface of the activated nano-silica, and react to form amide bonds under the action of an acylating agent to obtain nano-silica modified with amide groups.

[0019] Optionally, the acylating agent is dimethylformamide.

[0020] By adopting the above technical solution, dimethylformamide has good solubility, which helps the nano-silica to fully dissolve and react in the reaction, thereby helping to improve the efficiency and yield of the reaction. In addition, dimethylformamide has high reactivity and, as an acyl donor, reacts with the hydroxyl groups on the surface of the nano-silica to form an amide bond. The dimethylformamide itself can play a good catalytic role and promote the reaction.

[0021] Optionally, the oily additive is any one of cycloalkyl oil and polyether base oil.

[0022] By adopting the above technical solution, epoxyalkyl and polyether oily substances as oily additives have good heat resistance and inertness, which is beneficial to improving the performance of the interface agent.

[0023] Optionally, the raw materials further include 3-5 parts of fatty alcohol polyoxyethylene ether.

[0024] By adopting the above technical solution, fatty alcohol polyoxyethylene ether is added to emulsify the oily additives in the interface agent, which is beneficial to improving the stability of the interface agent and avoiding sedimentation during long-term storage, thereby reducing the performance of the interface agent.

[0025] In a second aspect, the present application provides a method for preparing an aluminum template interface agent, which adopts the following technical solution:

[0026] A method for preparing an aluminum template interface agent comprises the following steps:

[0027] (1) mixing base oil, fatty acid soap and terephthalic acid monoamide, heating and stirring to react, to obtain a mixed solution;

[0028] (2) adding modified nano-silica to the heated mixed solution, stirring evenly, then adding organic bentonite to react with polyvinyl alcohol, adding a pH regulator, stirring evenly, and obtaining the aluminum template interface agent.

[0029] In summary, this application has the following beneficial effects:

[0030] 1. Since the present application adopts a network structure formed by modified polysiloxane, organic bentonite, polyvinyl alcohol, terephthalic acid monoamide, base oil and fatty acid soap, the surface of the film is easy to demould after forming and does not stick to the concrete. It has a good ability to prevent heat loss from the concrete surface, reduce the temperature difference between the inside and outside of the concrete, and ensure the performance of the concrete.

[0031] 2. In this application, nano-silica modified with amide groups is preferably used. Due to the good thermal insulation and heat-preventing ability of silica itself, the introduction of amide groups into it increases its dispersibility in the interface agent, improves its thermal insulation performance, and further improves the performance of the interface agent, which has better demoulding performance and thermal insulation ability. DETAILED DESCRIPTION

[0032] The present application is further described in detail below with reference to the embodiments.

[0033] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or those recommended by the manufacturer. All reagents or instruments used, if the manufacturer is not specified, are commercially available conventional products.

[0034] AEO-9 fatty alcohol polyoxyethylene ether was purchased from Shandong Yihui Chemical Co., Ltd. with a polymerization degree of 9; polyether base oil was purchased from Hebei Gongtian Lubrication Technology Co., Ltd., model GL-5; cyclohexane oil was purchased from Dongguan Beishan Lubricating Oil Co., Ltd., model K30.

[0035] Preparation examples of raw materials and / or intermediates

[0036] Preparation Example 1

[0037] A modified nano-silica, the preparation of which comprises the following steps:

[0038] (1) 4 kg of sodium hydroxide, 4 kg of hydrogen peroxide and 4 kg of deionized water were mixed to prepare a mixed solution 1, 8 kg of nano-silica was added, the mixture was placed in a water bath and adjusted to 90° C., heated for 2 h, washed with deionized water until the washing solution was neutral, and dried at 70° C. to constant weight to obtain alkalized nano-silica;

[0039] (2) 8 kg of the alkalized silica was added to a mixed solution 2 prepared by mixing 1.05 kg of acetic anhydride (acylating agent), 1.32 kg of 3-aminopropyltriethoxysilane and 2.63 kg of deionized water. After the air in the reactor was removed by nitrogen, the reactor was sealed and reacted for 5 hours. After the reaction was completed, the reactor was washed and dried to obtain amide group-modified nano-silica.

[0040] Preparation Example 2

[0041] A modified nano-silica is different from Preparation Example 1 in that the acylating agent used in this Preparation Example is dimethylformamide.

[0042] Preparation Example 3

[0043] A modified nano-silica, the preparation of which comprises the following steps:

[0044] (1) 4 kg of sodium hydroxide, 4 kg of hydrogen peroxide and 4 kg of deionized water were mixed to prepare a mixed solution 1, 8 kg of nano-silica was added, the mixture was placed in a water bath and adjusted to 90° C., heated for 2 h, washed with deionized water until the washing solution was neutral, and dried at 70° C. to constant weight to obtain alkalized nano-silica;

[0045] (2) 8 kg of the alkalized silica was added to a mixed solution 2 prepared by mixing 0.53 kg of dimethylformamide (acylating agent), 0.66 kg of 3-aminopropyltriethoxysilane and 1.31 kg of deionized water. After the air in the reactor was removed by nitrogen, the reactor was sealed and reacted for 5 hours. After the reaction was completed, the reactor was washed and dried to obtain amide group-modified nano-silica.

[0046] Preparation Example 4

[0047] A modified nano-silica, which differs from Preparation Example 3 in the following ways:

[0048] (2) 8 kg of alkalized silica was added to a mixed solution 2 prepared by mixing 1 kg of dimethylformamide (acylating agent), 2 kg of 3-aminopropyltriethoxysilane and 2 kg of deionized water. After the air in the reactor was removed by nitrogen, the reactor was sealed and reacted for 5 hours. After the reaction was completed, the reactor was washed and dried to obtain amide group-modified nano-silica.

[0049] Preparation Example 5

[0050] A modified nano-silica, which differs from Preparation Example 3 in the following ways:

[0051] (1) 4 kg of sodium hydroxide, 4 kg of hydrogen peroxide and 6 kg of deionized water were mixed to prepare a mixed solution 1, 8 kg of nano-silica was added, the mixture was placed in a water bath and adjusted to 90° C., heated for 2 h, washed with deionized water until the washing solution was neutral, and dried at 70° C. to constant weight to obtain alkalized nano-silica;

[0052] (2) 8 kg of alkalized silica was added to a mixed solution 2 prepared by mixing 0.5 kg of dimethylformamide (acylating agent), 1 kg of 3-aminopropyltriethoxysilane and 1 kg of deionized water. After the air in the reactor was removed by nitrogen, the reactor was sealed and reacted for 5 hours. After the reaction was completed, the reactor was washed and dried to obtain amide group-modified nano-silica.

[0053] Preparation Example 6

[0054] A modified nano-silica, which differs from Preparation Example 3 in the following ways:

[0055] (1) 4 kg of sodium hydroxide, 4 kg of hydrogen peroxide and 4 kg of deionized water were mixed to prepare a mixed solution 1, 8 kg of nano-silica was added, the mixture was placed in a water bath and adjusted to 90° C., heated for 2 h, washed with deionized water until the washing solution was neutral, and dried at 70° C. to constant weight to obtain alkalized nano-silica;

[0056] (2) 8 kg of alkalized silica was added to a mixed solution 2 prepared by mixing 0.25 kg of dimethylformamide (acylating agent), 0.5 kg of 3-aminopropyltriethoxysilane and 0.5 kg of deionized water. After the air in the reactor was removed by nitrogen, the reactor was sealed and reacted for 5 hours. After the reaction was completed, the reactor was washed and dried to obtain amide group-modified nano-silica.

[0057] Example

[0058] Example 1

[0059] An aluminum template interface agent, the preparation of which comprises the following steps:

[0060] (1) 7 kg of mineral oil (oil additive), 9 kg of fatty acid soap, and 11 kg of terephthalic acid monoamide were mixed, heated to 55° C., and stirred at a speed of 5000 r / min for 25 min to obtain a mixed solution;

[0061] (2) Add 5 kg of modified nano-silica to the heated mixed solution, stir evenly, and then continue to add 6 kg of organic bentonite and 12 kg of polyvinyl alcohol to react to obtain the aluminum template interface agent. The modified nano-silica used in this example is the modified nano-silica prepared in Preparation Example 1.

[0062] Example 2-3

[0063] An aluminum template interface agent, which is different from Example 1 in that its raw material components and their corresponding weight parts are shown in Table 1.

[0064] Table 1 Raw materials and their weights in Examples 1-3 (kg)

[0065] Example 1 Example 2 Example 3 base oil 7 8.5 10 fatty acid soap 9 7.5 5 Terephthalic acid monoamide 11 8 9.5 Modified nanosilica 5 4 6 Organic bentonite 6 5 4 polyvinyl alcohol 12 10 11

[0066] Example 4

[0067] An aluminum template interface agent, which is different from Example 1 in that the modified nano-silica used in this example is the modified nano-silica prepared in Preparation Example 2.

[0068] Example 5

[0069] An aluminum template interface agent, which is different from Example 1 in that the modified nano-silica used in this example is the modified nano-silica prepared in Preparation Example 3.

[0070] Example 6

[0071] An aluminum template interface agent, which is different from Example 1 in that the modified nano-silica used in this example is the modified nano-silica prepared in Preparation Example 4.

[0072] Example 7

[0073] An aluminum template interface agent, which is different from Example 1 in that the modified nano-silica used in this example is the modified nano-silica prepared in Preparation Example 5.

[0074] Example 8

[0075] An aluminum template interface agent, which is different from Example 1 in that the modified nano-silica used in this example is the modified nano-silica prepared in Preparation Example 6.

[0076] Example 9

[0077] An aluminum template interface agent, which is different from Example 6 in that the oily additive used in this example is cyclohexane oil.

[0078] Example 10

[0079] An aluminum template interface agent, which is different from Example 8 in that the oily additive used in this example is a polyether base oil.

[0080] Example 11

[0081] An aluminum template interface agent, which is different from Example 6 in that this embodiment also includes 3 kg of AEO-9 fatty alcohol polyoxyethylene ether.

[0082] Comparative Example

[0083] Comparative Example 1

[0084] An aluminum template interface agent, which is different from Example 1 in that unmodified nano-silica is used in this comparative example.

[0085] Comparative Example 2

[0086] An aluminum template interface agent, which is different from Example 1 in that the nano-silica used in this comparative example is commercially available hydrophobic nano-silica.

[0087] Comparative Example 3

[0088] An aluminum template interface agent is different from Example 1 in that polyvinyl alcohol is not added in this comparative example.

[0089] Performance testing

[0090] Test methods

[0091] Demolding effect: Spray the prepared interface agent evenly on a clean, dry aluminum formwork and allow it to air dry to form a film. Test the demolding effect of the interface agent according to the method in Appendix A of JC / T949-2021 "Release Agents for Concrete Products". After the concrete is demolded, collect the concrete material adhered to the working surface of the aluminum formwork and calculate the adhesion amount per unit area.

[0092] Peel force: The prepared interface agent was evenly sprayed on a clean, dry aluminum template and allowed to air dry to form a film. The force applied to the standard pressure-sensitive tape when peeled from the template surface was then tested using a BLD-200N electronic peel tester. The peel force was recorded until the film was damaged and could no longer completely cover the template. The peel test conditions were 180° and 25 mm / min.

[0093] Centrifugal stability: 8 mL of the emulsion was injected into a 10 mL screw-cap centrifuge tube, placed in a high-speed centrifuge, and the speed was set to 9000 r / min. After centrifugation for 5 minutes, its stability was evaluated;

[0094] Thermal conductivity test: Use thermal conductivity tester, model: KM1-DRL-III, and refer to standard ASTM-D5470-12 to test the thermal conductivity of the interface agent after it is evenly sprayed on a clean and dry aluminum template and naturally dried to form a film.

[0095] Table 2 Performance test results

[0096]

[0097]

[0098] Combining Examples 1-3 and Comparative Examples 1-2 and Table 2, it can be seen that the various test data of Examples 1-3 are better than those of Comparative Examples 1-2, indicating that the modification of nano-silica by the present application can improve the dispersibility of silica in the interface agent, further improving the ability of the interface agent to insulate and prevent heat dissipation.

[0099] Combining Examples 1-3 and Comparative Example 3 and Table 2, it can be seen that the various test data of Examples 1-3 are better than those of Comparative Example 3, indicating that the addition of polyvinyl alcohol has good film-forming properties, contributes to the formation of the network structure in the interface agent, and further improves the various properties of the interface agent.

[0100] Combining Examples 1-4 and Table 2, it can be seen that the experimental data of Example 4 are all better than those of Examples 1-3, indicating that when the acylating agent used is dimethylformamide, the efficiency and yield of the modification can be improved, the completion of the modification reaction can be promoted, and thus the demoulding ability of the interface agent can be improved.

[0101] From Examples 4-7 and Table 2, it can be seen that the modified nano-silica prepared by the method of the present application has good dispersibility in the interface agent, and can also exert good thermal insulation performance to ensure the demoulding effect of the interface agent.

[0102] Combining Example 1 with Example 8 and Table 2, it can be seen that the various test data of Example 8 are better than those of Example 1. The ratio of the amount of alkalized nano-silica added to the mixed solution 2 in Preparation Example 6 is 4:1. When the ratio exceeds the ratio of the method of the present application, good modification of the nano-silica cannot be achieved, resulting in a low amidation rate, reducing the performance of the interface agent, and causing a decrease in the demolding effect.

[0103] Combining Example 6 with Examples 9-10 and Table 2, it can be seen that the experimental data of Examples 9-10 are all better than those of Example 6, indicating that the selection of cycloalkyl oil or polyether base oil as the oil additive has better heat resistance than the selection of general mineral oil, which is beneficial to ensuring the demoulding effect of the surface of the interface agent.

[0104] Combining Example 8 with Example 11 and Table 2, it can be seen that the stability of the interface agent prepared in Example 11 is significantly better than that in Example 8, indicating that fatty alcohol polyoxyethylene ether can improve the stability of the interface agent, avoid particle sedimentation, and thus improve the performance of the interface agent.

[0105] Combined with the peeling force test, the interface agent forms an isolation layer on the template surface, which can greatly reduce the critical surface tension value of the template and significantly reduce the adhesion between the template and the pressure-sensitive tape. Therefore, the initial peeling force is very small, and each peeling process is a destruction of the interface agent. As the number of peelings increases, the damage to the cohesive layer becomes more and more serious, and the critical surface tension value of the template increases rapidly. Therefore, the peeling force becomes significantly larger in the later stage of the peeling test.

[0106] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. An aluminum template interface agent, characterized in that It includes the following raw materials in parts by weight: 10-12 parts of polyvinyl alcohol, 4-6 parts of modified nano-silica, 4-6 parts of organic bentonite, 8-11 parts of terephthalic acid monoamide, 7-10 parts of oily additive, 5-9 parts of fatty acid soap, and 0.5-1 part of pH adjuster, wherein the modified nano-silica is nano-silica modified with an amide group; and the oily additive is any one of a cycloalkyl oil and a polyether-based oil. The modified nano-silica is prepared by the following method: (1) adding nano-silica to a mixed solution 1 for hydrothermal reaction, followed by washing and drying to obtain alkalized nano-silica, wherein the mixed solution 1 is a mixture of sodium hydroxide, hydrogen peroxide and deionized water; (2) adding the alkalized silica to the mixed solution 2, removing the air in the reactor with an inert gas to react, washing and drying after the reaction is completed to obtain amide group-modified nano-silica, wherein the mixed solution 2 is a mixture of an acylating agent, 3-aminopropyltriethoxysilane and deionized water; the mass ratio of the alkalized silica to the mixed solution 2 in step (2) is (1.6-3.2):1; the acylating agent is dimethylformamide; The raw materials also include 3-5 parts of fatty alcohol polyoxyethylene ether.

2. The aluminum template interface agent according to claim 1, characterized in that: In the step (1), the mass ratio of sodium hydroxide, hydrogen peroxide and deionized water in the mixed solution 1 is 1:1:(1-1.5).

3. The aluminum template interface agent according to claim 1, characterized in that: The mass ratio of the acylating agent, 3-aminopropyltriethoxysilane and deionized water in the mixed solution 2 is (0.8-1):(1-2):2.

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