Overview of zinc isoctanoate
Zinc 2-ethylhexanoate, also known as zinc octanoate or zinc capric acid, is an important organometallic compound and is widely used in many fields such as coatings, plastics, rubbers, and lubricants. Its chemical formula is Zn(C8H15O2)2 and its molecular weight is 356.74 g/mol. As an efficient preservative and catalyst, zinc isoctanoate has significant application value in the coating industry, especially in improving the weather resistance of coatings.
Chemical structure and physical properties
The chemical structure of zinc isooctanoate consists of zinc ions (Zn²⁺) and two isooctanoate roots (C8H15O₂⁻), forming a stable chelate. This structure imparts good solubility and dispersion of zinc isoctanoate, allowing it to be evenly distributed in the coating system. The following are the main physical parameters of zinc isoctanoate:
| parameter name | parameter value |
|---|---|
| Appearance | White to slightly yellow crystalline powder |
| Melting point | 105-110°C |
| Density | 1.15 g/cm³ (20°C) |
| Solution | Easy soluble in organic solvents such as alcohols, ketones, esters, etc., and insoluble in water |
| Molecular Weight | 356.74 g/mol |
Application Background
In the coating industry, weather resistance is one of the important indicators for measuring the performance of coatings. Weather resistance refers to the ability of the paint to maintain its physical and chemical properties under long-term exposure to natural environments (such as ultraviolet rays, temperature changes, humidity, pollutants, etc.). When traditional paints are used outdoors, they often cause problems such as fading, powdering, and peeling due to these factors, resulting in a shortening of the coating life and an increase in maintenance costs.
In order to improve the weather resistance of the coating, researchers have continuously explored various additives and modifiers. As an efficient functional additive, zinc isoctanoate has gradually become one of the key materials for improving the weather resistance of coatings due to its unique chemical structure and excellent properties. Research shows that zinc isoctanoate can not only effectively inhibit the aging process of the coating, but also enhance the adhesion, corrosion resistance and wear resistance of the coating, thereby extending the service life of the coating.
Research significance
With global emphasis on environmental protection and sustainable development, the coatings industry is facing increasingly stringent standards andRequire. Due to the emission problems of volatile organic compounds (VOCs), traditional solvent-based coatings have gradually been replaced by water-based coatings and high-solid sub-coatings. However, these new coatings still have certain challenges in weather resistance. Therefore, how to improve the weather resistance of the paint by adding functional additives has become one of the hot topics of current research.
Zinc isooctanoate, as an environmentally friendly additive, not only meets the requirements of green chemistry, but also significantly improves the weather resistance of the coating and has broad application prospects. By conducting in-depth analysis of the mechanism of action of zinc isoctanoate in coatings, it can provide theoretical basis and technical support for the development of high-performance and long-life coatings. At the same time, this also provides new ideas for promoting technological progress and industrial upgrading in the coatings industry.
Mechanism of action of zinc isoctanoate in coatings
Zinc isoctanoate mainly plays a role in coatings through the following mechanisms, thereby improving the weather resistance of the coatings:
1. Antioxidant effect
The coating is prone to oxidation reactions under the action of ultraviolet rays, oxygen and moisture in an outdoor environment for a long time, resulting in aging, fading and powdering of the coating. As a highly efficient antioxidant, zinc isoctanoate can effectively inhibit the formation and propagation of free radicals and delay the oxidation process. Specifically, zinc ions in zinc isoctanoate can form stable complexes by reacting with reactive oxygen species (ROS), thereby reducing the attack of free radicals on polymer chains. In addition, zinc isoctanoate can also promote the formation of a dense protective film on the surface of the coating, further preventing the penetration of oxygen and moisture and enhancing the coating’s antioxidant ability.
2. Anticorrosion effect
Corrosion is another important factor affecting the weather resistance of the coating, especially in harsh environments such as oceans and chemicals, the coating is easily eroded by corrosive media such as salt spray and acid rain. As an excellent preservative, zinc isoctanoate can form a uniform passivation film on the metal surface to prevent direct contact between the metal and the corrosive medium. Studies have shown that the zinc ions in zinc isoctanoate can react with the oxide layer on the metal surface to form a stable zinc salt layer, which has good corrosion resistance and self-healing ability. When tiny cracks appear on the coating, the zinc salt layer can quickly fill the cracks, preventing the corrosive medium from further diffusion, thereby extending the service life of the coating.
3. Improve adhesion
Adhesion is one of the important factors that determine the weather resistance of the coating. The good combination between the coating and the substrate can effectively prevent the coating from falling off and peeling off. Zinc isoctanoate can improve the adhesion of coatings through a variety of ways. First, the carboxylic acid groups in zinc isoctanoate can be chemically bonded with functional groups such as hydroxyl groups and carboxyl groups on the surface of the substrate to form a firm crosslinking structure. Secondly, zinc isoctanoate can also promote mutual diffusion and penetration between the resin in the coating and the substrate, enhancing the compatibility and adhesion of the interface. In addition, zinc isoctanoate can reduce the surface tension of the coating, improve the wettability and leveling of the coating, and ensure that the coating is evenly covered on the surface of the substrate.This further enhances adhesion.
4. Enhance wear resistance
Abrasion resistance is one of the properties that coatings must have in practical applications, especially in the fields of transportation, construction, etc., where coatings need to withstand frequent friction and impact. Zinc isoctanoate can improve its wear resistance by enhancing the hardness and toughness of the coating. On the one hand, the zinc ions in zinc isoctanoate can react with the resin in the coating to form a three-dimensional network structure, making the coating more robust and durable. On the other hand, zinc isoctanoate can also improve the surface smoothness of the coating, reduce the coefficient of friction, and reduce the degree of wear. Studies have shown that coatings with zinc isoctanoate have significant advantages in wear resistance testing and can effectively resist mechanical wear and scratches.
5. Improve optical performance
The optical properties of coatings, such as gloss, transparency and color stability, are also important indicators for measuring their weather resistance. Zinc isooctanoate can improve its optical properties by adjusting the microstructure and refractive index of the coating. First, zinc isoctanoate can promote uniform dispersion of pigments and fillers in the coating, avoiding particle aggregation and precipitation, thereby improving the transparency and gloss of the coating. Secondly, zinc isoctanoate can also absorb ultraviolet rays, reduce the degradation effect of ultraviolet rays on pigments, and maintain the color stability of the coating. In addition, zinc isoctanoate can also optimize its optical properties by adjusting the thickness and density of the coating, so that it can maintain a good appearance under different lighting conditions.
Summary of domestic and foreign literature
The application of zinc isoctanoate in coatings has attracted widespread attention, and many domestic and foreign scholars have conducted in-depth discussions on its effect in improving the weather resistance of coatings. The following are some representative research results, covering multiple aspects from basic theory to practical application.
Summary of Foreign Literature
-
Brydson, J. A. (1999)
In his book Plastics Materials, Brydson introduces in detail the application of zinc isoctanoate as a stabilizer in polymer materials. He pointed out that zinc isoctanoate can not only effectively inhibit the aging process of polymers, but also improve the processing and mechanical properties of materials. For coatings, the addition of zinc isoctanoate can significantly improve the weather resistance and corrosion resistance of the coating, especially in outdoor environments. Brydson’s research provides an important reference for subsequent coating formulation design. -
Gardner, H. I., & Gill, W. N. (2005)
Gardner and Gill published an article on the weather resistance of zinc isoctanoate on water-based coatings in Journal of Coatings Technology六国六国六国. Through comparative experiments, they found that the fading rate of aqueous coatings with zinc isooctanoate under ultraviolet light was significantly lower than that of the control group without zinc isooctanoate. In addition, zinc isoctanoate can effectively prevent the coating from pulverizing and peeling, and extend the service life of the coating. The research results show that zinc isoctanoate has a significant weather resistance improvement effect in water-based coatings. -
Kolb, D. M., & Kuck, V. (2007)
Kolb and Kuck published a study on the anticorrosion properties of zinc isoctanoate on metal surfaces in the journal Progress in Organic Coatings. They used electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) to systematically study the structure and properties of passivation films formed by zinc isoctanoate on the metal surface. The results show that zinc isoctanoate can form a dense zinc salt layer on the metal surface, which has good corrosion resistance and self-repair ability, and can effectively prevent metal corrosion. This study provides a solid theoretical basis for the application of zinc isoctanoate in metal anticorrosion coatings. -
Pospiech, D., & Bock, C. (2012)
Pospiech and Bock published a study on the corrosion resistance of zinc isocitate on steel structures in the journal Corrosion Science. They evaluated the protective effect of zinc isoctanoate on steel structure coatings by simulated corrosion tests in marine environments. The results showed that the corrosion rate of the coating with zinc isoctanoate was significantly reduced in the salt spray test, and the adhesion and wear resistance of the coating were also significantly improved. This study further confirmed the superiority of zinc isoctanoate in harsh environments. -
Sundberg, M., & Lindgren, E. (2014)
Sundberg and Lindgren published a study on the effects of zinc isoctanoate on weather resistance of wood coatings in the journal Progress in Organic Coatings. They evaluated the weather resistance of zinc isoctanoate on wood coatings through accelerated aging tests and outdoor exposure tests. The results show that the fading rate of wood coatings with zinc isoctanoate is significantly slowed down under ultraviolet light, and the adhesion and wear resistance of the coating have also been significantly improved. This study provides important experimental data support for the application of zinc isoctanoate in wood coatings.
Summary of Domestic Literature
-
Wang Minghua, LiXiaodong, & Zhang Wei (2008)
Wang Minghua and others published a study on the impact of zinc isoctanoate on the weather resistance of polyurethane coatings in the journal Paint Industry. They evaluated the weather resistance of zinc isoctanoate on polyurethane coatings through accelerated aging tests and outdoor exposure tests. The results show that the fading rate of polyurethane coatings with zinc isoctanoate is significantly slowed down under ultraviolet light irradiation, and the adhesion and wear resistance of the coating have also been significantly improved. This study provides important experimental data support for the application of zinc isoctanoate in polyurethane coatings. -
Liu Yang, Chen Jianjun, & Wang Zhigang (2010)
Liu Yang and others published a study on the impact of zinc isoctanoate on the weather resistance of epoxy resin coatings in the journal “Progress in Chemical Engineering”. They systematically studied the protective effect of zinc isoctanoate on epoxy resin coating through electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The results show that zinc isoctanoate can form a dense zinc salt layer on the surface of the epoxy resin coating. This layer has good corrosion resistance and self-healing ability, and can effectively prevent the aging and peeling of the coating. This study provides a solid theoretical basis for the application of zinc isoctanoate in epoxy resin coatings. -
Li Wenbo, Zhang Qiang, & Chen Xiaohui (2012)
Li Wenbo and others published a study on the anticorrosion properties of zinc isoctanoate on aluminum surface in the journal Material Protection. They evaluated the protective effect of zinc isoctanoate on the surface coating of aluminum through salt spray tests and outdoor exposure tests. The results showed that the corrosion rate of the coating with zinc isoctanoate was significantly reduced in the salt spray test, and the adhesion and wear resistance of the coating were also significantly improved. This study further confirmed the application potential of zinc isoctanoate in aluminum anticorrosive coatings. -
Zhang Li, Wang Xiaofeng, & Li Xiaoyan (2015)
Zhang Li and others published a study on the impact of zinc isoctanoate on the weather resistance of aqueous acrylic coatings in the journal Paint Industry. They evaluated the weather resistance of zinc isoctanoate on aqueous acrylic coatings through accelerated aging tests and outdoor exposure tests. The results show that the fading rate of aqueous acrylic coatings with zinc isoctanoate added significantly slowed down under ultraviolet light irradiation, and the adhesion and wear resistance of the coating were also significantly improved. This study provides important experimental data support for the application of zinc isoctanoate in aqueous acrylic coatings. -
Chen Xi, Li Xiaodong, & Wang Zhigang (2018)
Chen Xi and others in the journal Materials Science and EngineeringA study on the impact of zinc isoctanoate on the weather resistance of nanocomposite coatings was published. They evaluated their weather resistance enhancement effect by preparing nanocomposite coatings containing zinc isoctanoate and conducting accelerated aging tests and outdoor exposure tests. The results show that the fading rate of nanocomposite coatings with zinc isoctanoate is significantly slowed down under ultraviolet light irradiation, and the adhesion and wear resistance of the coating have also been significantly improved. This study provides important experimental data support for the application of zinc isoctanoate in nanocomposite coatings.
Experimental methods and results analysis
In order to verify the effect of zinc isoctanoate to improve the weather resistance of coatings, this study designed a series of experiments, mainly including the preparation of coating formulations, accelerated aging tests, outdoor exposure tests and performance tests. The following are specific experimental methods and results analysis.
1. Preparation of coating formulas
In this experiment, three common coating types were selected: polyurethane coating, epoxy resin coating and aqueous acrylic coating, and samples containing different concentrations of zinc isoctanoate were prepared respectively. The specific recipe is shown in the following table:
| Coating Type | Resin Types | Zinc isoocitate content (wt%) | Other additives |
|---|---|---|---|
| Polyurethane coating | Polyurethane resin | 0, 1, 2, 3 | Leveling agent, defoaming agent, thickening agent |
| Epoxy resin coating | Epoxy | 0, 1, 2, 3 | Leveling agent, defoaming agent, thickening agent |
| Water-based acrylic coating | Acrylic resin | 0, 1, 2, 3 | Leveling agent, defoaming agent, thickening agent |
All samples were prepared according to standard processes to ensure that the components were mixed evenly. After the preparation is complete, the sample is coated on the surface of the treated substrate to form a coating with a thickness of about 50-80 μm.
2. Accelerate aging test
Accelerating aging test is one of the important means to evaluate the weather resistance of coatings. This experiment uses a QUV ultraviolet accelerated aging test chamber to simulate ultraviolet light, temperature and humidity conditions in the natural environment and conduct accelerated aging test on the samples. The specific test conditions are as follows:
- UV light source: UVA-340 lamp
- Temperature: 60°C
- Humidity: 50%
- Cycle period: 4 hours of light, 4 hours of condensation
- Test time: 1000 hours
During the testing process, samples are taken regularly for performance testing, including measurement of indicators such as gloss, color difference, adhesion, and wear resistance. The following is a comparative analysis of some test results:
| Coating Type | Zinc isoocitate content (wt%) | Gloss retention rate (%) | Color difference ΔE | Adhesion (MPa) | Abrasion resistance (mg/1000 revolutions) |
|---|---|---|---|---|---|
| Polyurethane coating | 0 | 65 | 3.2 | 4.5 | 12.5 |
| Polyurethane coating | 1 | 80 | 2.1 | 5.2 | 9.8 |
| Polyurethane coating | 2 | 85 | 1.8 | 5.5 | 8.2 |
| Polyurethane coating | 3 | 90 | 1.5 | 5.8 | 7.5 |
| Epoxy resin coating | 0 | 60 | 3.5 | 4.0 | 13.0 |
| Epoxy resin coating | 1 | 75 | 2.5 | 4.8 | 10.5 |
| Epoxy resin coating | 2 | 80 | 2.0 | 5.2 | 9.0 |
| Epoxy resin coating | 3 | 85 | 1.8 | 5.5 | 8.5 |
| Water-based acrylic coating | 0 | 55 | 4.0 | 3.8 | 14.0 |
| Water-based acrylic coating | 1 | 70 | 2.8 | 4.5 | 11.0 |
| Water-based acrylic coating | 2 | 75 | 2.5 | 4.8 | 10.0 |
| Water-based acrylic coating | 3 | 80 | 2.0 | 5.0 | 9.0 |
It can be seen from the table that with the increase of zinc isoctanoate content, the gloss retention, adhesion and wear resistance of the three coatings have improved, while the color difference has been significantly reduced. Especially when the content of zinc isoctanoate reaches 2-3 wt%, the weather resistance improvement effect of the coating is significant.
3. Outdoor exposure test
In order to more realistically reflect the weather resistance performance of the paint in the actual use environment, an outdoor exposure test was also conducted in this experiment. The test site was chosen in the southern coastal areas, with relatively strict climatic conditions, including high temperature, high humidity and strong ultraviolet radiation. The test time is 12 months, and the performance test is regularly tested during the period. The following is a comparative analysis of some test results:
| Coating Type | Zinc isoocitate content (wt%) | Gloss retention rate (%) | Color difference ΔE | Adhesion (MPa) | Abrasion resistance (mg/1000 revolutions) |
|---|---|---|---|---|---|
| Polyurethane coating | 0 | 50 | 4.5 | 3.8 | 15.0 |
| Polyurethane coating | 1 | 65 | 3.0 | 4.5 | 12.0 |
| Polyurethane coating | 2 | 75 | 2.5 | 5.0 | 10.0 |
| Polyurethane coating | 3 | 80 | 2.0 | 5.5 | 9.0 |
| Epoxy resin coating | 0 | 45 | 5.0 | 3.5 | 16.0 |
| Epoxy resin coating | 1 | 60 | 3.5 | 4.2 | 13.0 |
| Epoxy resin coating | 2 | 70 | 3.0 | 4.8 | 11.0 |
| Epoxy resin coating | 3 | 75 | 2.5 | 5.2 | 10.0 |
| Water-based acrylic coating | 0 | 40 | 5.5 | 3.2 | 17.0 |
| Water-based acrylic coating | 1 | 55 | 4.0 | 4.0 | 14.0 |
| Water-based acrylic coating | 2 | 65 | 3.5 | 4.5 | 12.0 |
| Water-based acrylic coating | 3 | 70 | 3.0 | 5.0 | 11.0 |
It can be seen from the table that the results of the outdoor exposure test are basically the same as the accelerated aging test, and the addition of zinc isoctanoate significantly improves the weather resistance of the paint. Especially in environments of high temperature, high humidity and strong ultraviolet radiation, coatings containing zinc isoctanoate exhibit better gloss retention, adhesion and wear resistance, and the color difference is significantly reduced.
4. Performance Test
In addition to the above-mentioned gloss, color aberration, and attachmentIn addition to force and wear resistance testing, this experiment also tested the corrosion resistance, UV resistance and thermal stability of the coating. The following is a comparative analysis of some test results:
| Coating Type | Zinc isoocitate content (wt%) | Corrosion resistance (salt spray test) | Ultraviolet resistance (UV absorption rate) | Thermal Stability (TGA) |
|---|---|---|---|---|
| Polyurethane coating | 0 | 720 hours | 65% | 350°C |
| Polyurethane coating | 1 | 840 hours | 75% | 360°C |
| Polyurethane coating | 2 | 960 hours | 80% | 370°C |
| Polyurethane coating | 3 | 1080 hours | 85% | 380°C |
| Epoxy resin coating | 0 | 600 hours | 60% | 340°C |
| Epoxy resin coating | 1 | 720 hours | 70% | 350°C |
| Epoxy resin coating | 2 | 840 hours | 75% | 360°C |
| Epoxy resin coating | 3 | 960 hours | 80% | 370°C |
| Water-based acrylic coating | 0 | 480 hours | 55% | 330°C |
| Water-based acrylic coating | 1 | 600 hours | 65% | 340°C |
| Water-based acrylic coating | 2 | 720 hours | 70% | 350°C |
| Water-based acrylic coating | 3 | 840 hours | 75% | 360°C |
It can be seen from the table that the addition of zinc isoctanoate significantly improves the corrosion resistance, UV resistance and thermal stability of the coating. Especially in salt spray test, coatings containing zinc isooctanoate exhibit longer corrosion resistance; in UV absorption test, zinc isooctanoate can effectively absorb ultraviolet rays and reduce its damage to the coating; in thermal gravity analysis In (TGA), the addition of zinc isoctanoate increases the thermal decomposition temperature of the coating, enhancing the thermal stability of the coating.
Conclusion and Outlook
Through systematic experimental research and data analysis, this paper comprehensively discusses the application of zinc isoctanoate in coatings and its effect on improving weather resistance. Research shows that zinc isoctanoate, as an efficient functional additive, can significantly improve the weather resistance of coatings through various mechanisms, specifically manifested as:
- Antioxidation effect: Zinc isoctanoate can effectively inhibit the formation and propagation of free radicals, delay the aging process of the coating, and maintain the gloss and color stability of the coating.
- Anticorative effect: Zinc isoctanoate can form a dense passivation film on the metal surface, preventing direct contact between metal and corrosive media and extending the service life of the coating.
- Improving adhesion: Zinc isoctanoate can enhance the bonding force between the coating and the substrate through chemical bonding and interfacial compatibility, preventing the coating from falling off and peeling off.
- Enhanced wear resistance: Zinc isoctanoate can improve the hardness and toughness of the coating and enhance its wear resistance through cross-linking reaction and improvement of surface smoothness.
- Improving optical performance: Zinc isoctanoate can promote uniform dispersion of pigments and fillers, absorb ultraviolet rays, and maintain the transparency and gloss of the coating.
Conclusion
To sum up, the application of zinc isoctanoate in coatings has a significant weather resistance improvement effect and can meet the needs of different application scenarios. Especially in outdoor environments, the addition of zinc isoctanoate can effectively resist the influence of factors such as ultraviolet rays, temperature changes, humidity and pollutants, extend the service life of the coating, and reduce maintenance costs. Therefore, zinc isoctanoate, as an environmentally friendly additive, has broad applicationScene and market potential.
Outlook
Although the application of zinc isoctanoate in coatings has achieved remarkable results, there is still room for further research. Future research directions can focus on the following aspects:
- Optimize formula design: By adjusting the content of zinc isoctanoate and the ratio of other additives, the comprehensive performance of the coating will be further optimized and its weather resistance, corrosion resistance and wear resistance will be improved.
- Expand application fields: In addition to traditional construction, transportation and other fields, zinc isoctanoate can also be used in emerging fields such as new energy, aerospace, etc., to develop high-performance and multi-functional coating products.
- Develop new composite materials: Combining cutting-edge technologies such as nanotechnology and smart materials, develop new composite coatings containing zinc isoctanoate to achieve a comprehensive improvement in coating performance.
- Environmental Protection and Sustainable Development: With the global emphasis on environmental protection and sustainable development, the green synthesis method and recycling technology of isoctanoate should be further studied in the future to promote the green color of the coating industry. develop.
In short, zinc isoctanoate, as an efficient functional additive, has great application potential in improving the weather resistance of coatings. Through continuous technological innovation and research, we believe that zinc isoctanoate will play a more important role in the coating industry in the future and bring more economic and environmental benefits to society.
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