CN118813326A - A concrete release agent and preparation method thereof - Google Patents

Abstract

The invention discloses a concrete release agent and a preparation method thereof, which belong to the technical field of concrete release agents, and the concrete release agent comprises the following components: soybean oil: 10-20 parts of a lubricant; and (3) compounding an emulsifying agent: 1.2-4.8 parts; xanthan gum: 0.001-0.004 parts; dimethicone: 0.04-0.09 parts; triethanolamine: 0.002-0.008 parts; calcium formate: 1-9 parts of deionized water: 66-88 parts. The soybean oil is used as a basic system of the mixed emulsion, and span-60, tween-80, triethanolamine dodecylbenzenesulfonate and octylphenol polyoxyethylene ether are respectively added as main film forming substances of the release agent, so that the release agent has the advantages of good film forming property, good release effect, no pollution to concrete members and the like while having the environment friendliness. Therefore, the concrete release agent and the preparation method thereof solve the technical problem that the existing release agent easily pollutes the surface of a concrete member.

Description

A concrete release agent and preparation method thereof

Technical Field

The invention relates to the technical field of concrete release agents, in particular to a concrete release agent and a preparation method thereof.

Background Art

Concrete release agent, also known as concrete isolation agent or release lubricant, is a substance or material that is coated or sprayed on the inner surface of the formwork to produce a layer of isolation film to lubricate and isolate. It can effectively reduce the adhesion between concrete and the formwork, allowing the concrete to smoothly separate from the formwork when demolding, thereby keeping the shape of the concrete intact and smooth.

In the construction of concrete projects, quality defects such as honeycomb surface, missing corners, exposed steel bars, etc. often appear on the surface of concrete components, and their oxidation resistance and weathering degree are low. In order to solve these problems, the construction unit performs secondary treatment on the concrete surface, but it is easy to peel off and fail to fundamentally improve the quality of concrete. With the development of new technologies and processes for concrete, the requirements for the decorative effect of the concrete surface are getting higher and higher. Problems such as honeycomb surface, missing corners, exposed steel bars not only affect the appearance of concrete, but also affect the intrinsic quality and durability of concrete in serious cases. The use of release agents can reduce or even avoid the above-mentioned problems on the surface of concrete components and improve the quality level of the component surface. High-quality concrete release agents can even achieve a mirror effect, the so-called mirror concrete, which also improves the strength of concrete to a certain extent. The exquisite appearance of concrete components can not only reflect the management level of the construction unit and the overall quality of the operators, but also reflect the reliability of the intrinsic quality of the entire project and the beauty of art.

As an indispensable concrete admixture, the use of release agent can significantly reduce the adsorption force between concrete and formwork, reduce or prevent the adhesion of concrete to the formwork surface, and make it peel off from the formwork smoothly. The edges and corners of concrete components are neat and intact, and the surface color is uniform, smooth and flat, ensuring the quality of prefabricated parts. After demoulding, the formwork is easy to clean and labor productivity is improved. Therefore, it plays a very important role in the development and application of concrete technology and building materials.

Based on this, Chinese patent CN106113236A discloses a concrete component release agent, which includes 3-20 parts of phenylethanol, 20-70 parts of epoxy resin, 60-250 parts of diesel, 30-80 parts of vegetable oil, 10-50 parts of paraffin, 2-15 parts of benzoic acid, 10-25 parts of calcium sulfate, and 10-35 parts of diethanolamine. Therefore, after using the release agent, demoulding is easy, labor intensity is improved, pollution is avoided, product brightness is high, yield rate is improved, and cost is reduced.

However, the concrete component release agent disclosed in the aforementioned patent still has the technical problem of easily contaminating the concrete surface. Specifically, the main components of the release agent disclosed in the prior art include mineral oil, animal oil, vegetable oil and a mixture of various oils. However, at present, most of them use mineral oil, that is, lubricating oil, machine oil, waste oil, etc. with low viscosity and good fluidity among petroleum industry products. Pure oil release agents have good isolation and lubrication properties and are easy to demold. They play a certain role in rust prevention for steel formwork or reinforced concrete formwork, and are a more satisfactory product. The only drawback is that it will contaminate the concrete surface and affect the subsequent decoration; the reaction between oil and alkali in concrete causes the concrete surface to powderize. It should be noted that waste oil may contain sulfuric acid that is harmful to formwork and concrete, as well as polychlorinated biphenyls that are harmful to the human body. Therefore, it should be used with extreme caution.

Summary of the invention

Based on this, it is necessary to provide a concrete release agent and a preparation method thereof in order to improve the technical problem that the release agent easily contaminates the surface of the concrete component.

A concrete release agent, comprising the following components in parts by weight:

Soybean oil: 10-20 parts;

Compound emulsifier: 1.2-4.8 parts;

Xanthan gum: 0.001-0.004 parts;

Dimethyl silicone oil: 0.04-0.09 parts;

Triethanolamine: 0.002-0.008 parts;

Calcium formate: 1-9 parts;

Deionized water: 66-88 parts.

Further, the compound emulsifier includes the following components in parts by weight:

Span-60: 0.3-1.2 parts;

Tween-80: 0.3-1.2 parts;

Dodecylbenzenesulfonic acid triethanolamine salt: 0.3-1.2 parts;

Octylphenol polyoxyethylene ether: 0.3-1.2 parts.

Further, a composite emulsifier includes the following components in parts by weight:

Span -60:0.9;

Tween-80: 0.9 parts;

Dodecylbenzenesulfonic acid triethanolamine salt: 0.9 parts;

Octylphenol polyoxyethylene ether: 0.9 parts.

Further, another composite emulsifier includes the following components in parts by weight:

Span-60: 0.6 parts;

Tween-80: 0.9 parts;

Dodecylbenzenesulfonic acid triethanolamine salt: 0.6 parts;

Octylphenol polyoxyethylene ether: 0.9 parts.

Further, another composite emulsifier includes the following components in parts by weight:

Span-60: 1.2 parts;

Tween-80: 0.3 parts;

Dodecylbenzenesulfonic acid triethanolamine salt: 1.2 parts;

Octylphenol polyoxyethylene ether: 0.3 parts.

Furthermore, a method for preparing the aforementioned concrete release agent comprises the following steps:

S1: First, prepare the materials according to the formula: soybean oil: 10-20 parts; composite emulsifier: 1.2-4.8 parts; xanthan gum: 0.001-0.004 parts; dimethyl silicone oil: 0.04-0.09 parts; triethanolamine: 0.002-0.008 parts; calcium formate: 1-9 parts; deionized water: 66-88 parts;

S2: Prepare composite emulsion using composite emulsifier:

S3: Pour the prepared soybean oil into the reaction vessel, and slowly add the composite emulsifier at a stirring speed of 600-800 r/min until the composite emulsifier is completely dispersed in the soybean oil; at this time, the system appears yellow and slightly turbid;

S4: Increase the stirring speed to 1000-1200 r/min; under high-speed dispersing stirring, slowly add xanthan gum, dimethyl silicone oil, triethanolamine, calcium formate and half of the prepared deionized water to the system of step S3 until the emulsion phase changes; at this time, stop adding deionized water and maintain stirring for 10 minutes;

S5: Increase the dispersion speed to 1200-1500r/min, and slowly add half of the remaining deionized water at the same time. The total time for adding deionized water is controlled within 20 minutes;

S6: Increase the dispersion speed to 1500r/min, continue stirring for 20 minutes, quickly add all the remaining deionized water, and reduce the speed to 1200r/min, continue stirring for 10 minutes and then discharge.

In summary, a concrete release agent and a preparation method thereof of the present invention use soybean oil as the basic system of the release agent emulsion, and respectively add Span-60, Tween-80, triethanolamine dodecylbenzenesulfonate and octylphenol polyoxyethylene ether as the main film-forming substances of the release agent, so that the release agent has the advantages of good film-forming property and good demoulding effect. At the same time, because the soybean oil emulsion system can make the concrete surface of the concrete component smooth after demoulding and reduce the honeycomb bubbles on its surface; so that the surface of the concrete component product will not have the defect of residual impregnation marks, and thus will not affect the yield of secondary processing such as subsequent decoration of secondary concrete components. In addition, soybean oil has the characteristics of being renewable, and partially replacing non-renewable mineral oil with it can improve the environmental protection of the process while controlling costs. In addition, xanthan gum is used as a stabilizer for the emulsified system, dimethyl silicone oil is used as a defoamer, triethanolamine is used as a rust preventer, and calcium formate is added to balance the negative effect of the oily release agent on cement hydration, so that the release agent proposed by the present invention can be adapted to the concrete component forming process of the steel formwork. Therefore, the concrete release agent and the preparation method thereof of the present invention solve the technical problem that the existing release agent easily contaminates the surface of the concrete component.

DETAILED DESCRIPTION

In order to make the above-mentioned purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation mode of the present invention is described in detail below in conjunction with embodiments. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

The present invention provides a concrete release agent, which comprises the following components in parts by weight:

Soybean oil: 10-20 parts;

Span-60: 0.3-1.2 parts;

Tween-80: 0.3-1.2 parts;

Dodecylbenzenesulfonic acid triethanolamine salt: 0.3-1.2 parts;

Octylphenol polyoxyethylene ether: 0.3-1.2 parts;

Xanthan gum: 0.001-0.004 parts;

Dimethyl silicone oil: 0.04-0.09 parts;

Triethanolamine: 0.002-0.008 parts;

Calcium formate: 1-9 parts;

Deionized water: 66-88 parts.

Furthermore, a method for preparing the aforementioned concrete release agent specifically comprises the following steps:

S1: First, prepare the materials according to the formula: soybean oil: 10-20 parts; composite emulsifier: 1.2-4.8 parts; xanthan gum: 0.001-0.004 parts; dimethyl silicone oil: 0.04-0.09 parts; triethanolamine: 0.002-0.008 parts; calcium formate: 1-9 parts; deionized water: 66-88 parts;

S2: Prepare composite emulsion using composite emulsifier:

S3: Pre-dispersing the composite emulsifier in soybean oil: Pour the prepared soybean oil into a reaction container, and slowly add the composite emulsifier at a preset stirring speed, such as 600-800 r/min, until the composite emulsifier is completely dispersed in the soybean oil; at this time, the system appears yellow and slightly turbid;

S4: Formation of emulsion: Increase the stirring speed to 1000-1200 r/min; under high-speed dispersing stirring, slowly add xanthan gum, dimethyl silicone oil, triethanolamine, calcium formate and half of the prepared deionized water to the system of step S3 until the emulsion phase changes; at this time, stop adding deionized water and maintain stirring for 10 minutes;

S5: Increase the dispersion speed to 1200-1500 r/min and then slowly add half of the remaining deionized water into the system; during this process, the total time for slowly adding deionized water is controlled within 20 minutes;

S6: After half of the deionized water has been added, increase the dispersion speed to 1500 r/min, continue stirring for 20 minutes, quickly add all the remaining deionized water, and reduce the speed to 1200 r/min. Continue stirring for 10 minutes before discharging.

Specifically, in the aforementioned step S2, the preparation examples of the composite emulsifier are respectively:

Composite emulsifier Example 1: Span-60: 0.3 parts, Tween-80: 1.2 parts, dodecylbenzenesulfonic acid triethanolamine salt: 0.3 parts and octylphenol polyoxyethylene ether: 1.2 parts;

Composite emulsifier Example 2: Span-60: 1.2 parts, Tween-80: 0.3 parts, dodecylbenzenesulfonic acid triethanolamine salt: 1.2 parts and octylphenol polyoxyethylene ether: 0.3 parts;

Composite emulsifier Example 3: Span-60: 0.6 parts, Tween-80: 0.9 parts, dodecylbenzenesulfonic acid triethanolamine salt: 0.6 parts and octylphenol polyoxyethylene ether: 0.9 parts;

Composite emulsifier Example 4: Span-60: 0.9 parts, Tween-80: 0.9 parts, dodecylbenzenesulfonic acid triethanolamine salt: 0.9 parts and octylphenol polyoxyethylene ether: 0.9 parts;

Example 5 of composite emulsifier: Span-60: 0.8 parts, Tween-80: 0.7 parts, triethanolamine dodecylbenzenesulfonate: 0.8 parts and octylphenol polyoxyethylene ether: 0.7 parts.

Specifically, stability is an important indicator of soybean oil emulsion release agent. After being coated on the formwork, the emulsion release agent with poor stability will cause uneven film thickness, which will seriously affect the demoulding effect and cause surface defects of concrete specimens. The demoulding performance of the release agent is the most important indicator, which can be characterized by the force used when demolding, the amount of concrete adhesion, and the appearance. Therefore, the key to the preparation of soybean oil emulsion lies in the selection of emulsifiers. Each emulsifier has a different hydrophilic-lipophilic balance value, i.e., HLB value. If a stable emulsion is prepared, the HLB value of the selected one or more emulsifiers should be as equal or close to that of the emulsified substance as possible to achieve the best effect.

Further, the soybean oil used in the concrete release agent of the present invention is also commonly referred to as soybean oil or soybean oil, which is an edible oil extracted from the plant soybean. It is one of the most produced oils in the world and has a wide range of applications. Soybean oil can be prepared by a variety of methods, including pressing and leaching. The pressing method is to squeeze the oil out of the soybean by mechanical pressure, while the leaching method is to use an organic solvent to dissolve the oil from the soybean. In addition, there are some new preparation methods such as water enzyme method and water substitution method, but these methods are not yet popular. Compared with mineral oils with limited stocks such as diesel and motor oil, the cost of soybean oil extracted from plants is cheaper and easier to source. Therefore, it is used to partially replace mineral oil and is applied to the concrete release agent industry, which can significantly improve the environmental protection performance of the release agent and make it easier to control costs.

Specifically, soybean oil cannot directly replace mineral oils such as motor oil or diesel for use. It needs to be emulsified according to the preset steps to obtain a stable emulsion system, and then the system is used as the main body, and a composite emulsifier is combined to form a semi-emulsified mixed system, and finally it can be used as the main film-forming substance of the release agent, so that the release agent has good film-forming properties and good demoulding effects. In the composite emulsifier system, Span-60, Tween-80, triethanolamine dodecylbenzenesulfonate and octylphenol polyoxyethylene ether are mutually dispersed in a deionized water solvent system to form a semi-emulsion system, and xanthan gum is used as a stabilizer of the semi-emulsified system, the dimethyl silicone oil is used as a defoamer, and the triethanolamine is used as a rust inhibitor, so that it is suitable for the concrete component forming process of the steel formwork.

Further, generally, the HLB value of common soybean oil is about 9.2. In the technical scheme of a concrete release agent of the present invention, it is proposed to use Span-60, Tween-80, triethanolamine dodecylbenzenesulfonate and octylphenol polyoxyethylene ether as a composite emulsifier, and five embodiments of the composite emulsifier are disclosed; according to the method of the concrete release agent proposed by the present invention, experiments are carried out using the embodiments of the five composite emulsifiers respectively, and the experiments are measured according to the relevant standards of the national standard GB/T11543-2008. Through the obtained different concrete release agents, the stability thereof and the selection relationship of the composite emulsifier are measured as shown in Table 1:

Table 1: Stability of concrete release agents obtained with different compound emulsifiers

As shown in the results of Table 1, when selecting Span-60, Tween-80, dodecylbenzenesulfonic acid triethanolamine salt and octylphenol polyoxyethylene ether these several surfactants to be compounded, emulsifying effect is all good, and the stability of emulsion is also higher. This is because several surfactants are compounded, and the surface tension of emulsion can be reduced, thereby stabilizing the emulsion. When emulsifier is compounded, these surfactants are ionized in water to produce electric charge, so that tiny oil droplets in the emulsion have the same electric charge, and by electrostatic action, the coagulation of droplets is prevented, which is conducive to emulsion stabilization. In addition, there is a strong synergistic effect between Tween-80 and dodecylbenzenesulfonic acid triethanolamine salt, and they can also form stable film on the surface of emulsion droplets, thereby promoting the stability of emulsion. After many experiments, it was found that when Span-60: 0.9, Tween-80: 0.9 parts, dodecylbenzenesulfonic acid triethanolamine salt: 0.9 parts and octylphenol polyoxyethylene ether: 0.9 parts are used as compound emulsifiers, the emulsification effect is best and the emulsion stability is the highest when the HLB value is 9.22.

Further, after repeated implementation, it is known that when the amount of compound emulsifier is small, the storage stability and centrifugal stability of the concrete release agent are relatively poor, which cannot meet the needs of the project. With the increase of the amount of compound emulsifier, the stability of the concrete release agent has been greatly improved, and when the amount of compound emulsifier reaches 3.6%, both stabilities of the release agent have achieved good results, wherein the storage stability has reached 90 days, which basically meets the requirements of the project. When the amount of compound emulsifier continues to increase to 4.8%, the stability of the concrete release agent is basically not much changed, but due to the increase in the amount of compound emulsifier, the concrete release agent has more bubbles in the process of preparation, which affects the use quality of the concrete release agent. And too much emulsifier also causes the increase of the cost of the concrete release agent, therefore, the optimal amount of the compound emulsifier is selected to be 3.6%.

Further, by weight, the following are three specific embodiments of a concrete release agent of the present invention:

Embodiment 1

Soybean oil: 10 parts;

Compound emulsifier: 3.6 parts;

Xanthan gum: 0.001 parts;

Dimethyl silicone oil: 0.04 parts;

Triethanolamine: 0.002 parts;

Calcium formate: 1 part;

Deionized water: 88 parts.

Embodiment 2

Soybean oil: 20 parts;

Compound emulsifier: 3.6 parts;

Xanthan gum: 0.004 parts;

Dimethyl silicone oil: 0.09 parts;

Triethanolamine: 0.008 parts;

Calcium formate: 9 parts;

Deionized water: 88 parts.

Embodiment 3

Soybean oil: 15 parts;

Compound emulsifier: 4.8 parts;

Xanthan gum: 0.004 parts;

Dimethyl silicone oil: 0.09 parts;

Triethanolamine: 0.006 parts;

Calcium formate: 6 parts;

Deionized water: 80 parts.

The above-mentioned Examples 1 to 3 and a commercially available ordinary mineral oil release agent are used as Comparative Examples 1 to 3, and each example is subjected to a release test on C30 ordinary concrete according to the test method described in "Release Agents for Concrete Products" (JC/T949-2005). The detailed experimental results are shown in Table 1 below.

Table 1: Release agent performance test results

Based on the release agent performance test results in Table 1, a horizontal comparison of the experimental results of Examples 1 to 3 with Comparative Examples 1 to 3 shows that the release agent product prepared using the formula and preparation method of a concrete release agent of the present invention has a release performance that is significantly better than that of ordinary concrete release agents on the market.

Furthermore, the oil-containing release agent provides good reliability for the apparent quality of concrete, but the oil will reduce the degree of cement hydration and delay C ₃ A hydration, thereby increasing the setting time and reducing the total amount of hydration products. Since the oil has a certain viscosity and affects the pores of hardened concrete, it has a negative impact on the mechanical properties of concrete. Therefore, the present invention introduces calcium formate as an early strength agent and adds it to the components of the concrete release agent. When the input amount reaches 1%, the negative impact of the release agent on cement hydration can be balanced. The optimal input amount is 3%, and the maximum input amount does not exceed 9%.

In summary, a concrete release agent and a preparation method thereof of the present invention use soybean oil as the basic system of the release agent emulsion, and respectively add Span-60, Tween-80, triethanolamine dodecylbenzenesulfonate and octylphenol polyoxyethylene ether as the main film-forming substances of the release agent, so that the release agent has the advantages of good film-forming property and good demoulding effect. At the same time, because the soybean oil emulsion system can make the concrete surface of the concrete component smooth after demoulding and reduce the honeycomb bubbles on its surface; so that the surface of the concrete component product will not have the defect of residual impregnation marks, and thus will not affect the yield of secondary processing such as subsequent decoration of secondary concrete components. In addition, soybean oil has the characteristics of being renewable, and partially replacing non-renewable mineral oil with it can improve the environmental protection of the process while controlling costs. In addition, xanthan gum is used as a stabilizer for the emulsified system, dimethyl silicone oil is used as a defoamer, triethanolamine is used as a rust preventer, and calcium formate is added to balance the negative effect of the oily release agent on cement hydration, so that the release agent proposed by the present invention can be adapted to the concrete component forming process of the steel formwork. Therefore, the concrete release agent and the preparation method thereof of the present invention solve the technical problem that the existing release agent easily contaminates the surface of the concrete component.

The technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above-described embodiments only express several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, several variations and improvements can be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims (6)

1. A concrete release agent, characterized in that it comprises the following components in parts by weight: Soybean oil: 10-20 parts; Compound emulsifier: 1.2-4.8 parts; Xanthan gum: 0.001-0.004 parts; Dimethyl silicone oil: 0.04-0.09 parts; Triethanolamine: 0.002-0.008 parts; Calcium formate: 1-9 parts; Deionized water: 66-88 parts. 2. A concrete release agent according to claim 1, characterized in that, in parts by weight, the compound emulsifier comprises the following components: Span-60: 0.3-1.2 parts; Tween-80: 0.3-1.2 parts; Dodecylbenzenesulfonic acid triethanolamine salt: 0.3-1.2 parts; Octylphenol polyoxyethylene ether: 0.3-1.2 parts. 3. A concrete release agent according to claim 2, characterized in that, in parts by weight, the compound emulsifier comprises the following components: Span -60:0.9; Tween-80: 0.9 parts; Dodecylbenzenesulfonic acid triethanolamine salt: 0.9 parts; Octylphenol polyoxyethylene ether: 0.9 parts. 4. A concrete release agent according to claim 2, characterized in that, in parts by weight, the compound emulsifier comprises the following components: Span-60: 0.6 parts; Tween-80: 0.9 parts; Dodecylbenzenesulfonic acid triethanolamine salt: 0.6 parts; Octylphenol polyoxyethylene ether: 0.9 parts. 5. A concrete release agent according to claim 2, characterized in that, in parts by weight, the compound emulsifier comprises the following components: Span-60: 1.2 parts; Tween-80: 0.3 parts; Dodecylbenzenesulfonic acid triethanolamine salt: 1.2 parts; Octylphenol polyoxyethylene ether: 0.3 parts. 6. A method for preparing a concrete release agent according to any one of claims 1 to 5, characterized in that it comprises the following steps: S1: First, prepare the materials according to the formula: soybean oil: 10-20 parts; composite emulsifier: 1.2-4.8 parts; xanthan gum: 0.001-0.004 parts; dimethyl silicone oil: 0.04-0.09 parts; triethanolamine: 0.002-0.008 parts; calcium formate: 1-9 parts; deionized water: 66-88 parts; S2: Prepare composite emulsion using composite emulsifier: S3: Pour the prepared soybean oil into the reaction vessel, and slowly add the composite emulsifier at a stirring speed of 600-800 r/min until the composite emulsifier is completely dispersed in the soybean oil; at this time, the system appears yellow and slightly turbid; S4: Increase the stirring speed to 1000-1200 r/min; under high-speed dispersing stirring, slowly add xanthan gum, dimethyl silicone oil, triethanolamine, calcium formate and half of the prepared deionized water to the system of step S3 until the emulsion phase changes; at this time, stop adding deionized water and maintain stirring for 10 minutes; S5: Increase the dispersion speed to 1200-1500r/min, and slowly add half of the remaining deionized water at the same time. The total time for adding deionized water is controlled within 20 minutes; S6: Increase the dispersion speed to 1500r/min, continue stirring for 20 minutes, quickly add all the remaining deionized water, and reduce the speed to 1200r/min, continue stirring for 10 minutes and then discharge.