Features and application of waterproof coating additives (2)

2.3 Film additive environmental protection
coating hydration, environmental protection trend is more and more obvious, the significance of green paint not only in the use of coatings, has been extended to coatings from production to packaging, construction, use of the whole process of low toxicity, harmless. And the development of coating additives will be based on environmental protection as the main line. Organic volatiles in coatings pose a direct hazard to the environment, society and humans themselves. Since 1967, when the Los Angeles area implemented regulations limiting the amount of solvents in coatings, foreign limits on the amount of solvents used in coatings have become more stringent, such as the U.S. Atmospheric Purification Act (1990), aim regulations (1998), the European Union Directive (1994), the European Community Ecomarker Product Standard (1999), japan's Indoor Building Coatings Standard (1997), and so on.
commonly used solvents such as toluene, xylene, butyl ketones, acetate, etc. are limited, ethanol is no exception. China on January 1, 2002 officially implemented the national mandatory standard GB 18582-2001 "interior decoration material interior wall paint in the limit of harmful substances" on the VOC made a limit of 200 g / L. For water-based coatings, film-forming additives are one of the main sources of VOC. Membrane additives, also known as polygenic aids, can promote the plastic flow and elastic deformation of latex particles, improve their fusion properties, can be filmed in a wide range of construction. Film-forming additives are usually solvents that evaporate very slowly, such as various types of alcohol ethers, alcohol ether acetates and alcohol esters. A variety of ways can be taken to reduce the effect of film additives on coating VOC, such as improving the performance of emulsions, so that they can be partially self-contained and reduce the amount of film additives. However, for Tg higher resin, its own membrane-forming poor, it must be assisted by film-forming additives to form a membrane. Therefore, in the emulsion technology has not been significant breakthrough stage, the environmental improvement of film-forming additives has become the main means of the current manufacturers. In addition to controlling the properties of the raw materials and product-based properties, another method is to change the volatilization of film-forming additives. Traditional film-forming additives completely escape in the final stages of film-forming, while film-forming additives with slower volatilization rates remain in the coating film for a longer period of time, making the coating film not completely hardened, water resistance and chemical resistance decreased. The improved film-forming additives can be absorbed by latex particles and retained in the paint film, thereby reducing volatility into the air, but at the same time can ensure that the various properties of the coating film do not have a negative impact.2.4 Functional coating additivesthe improvement of living standards makes human living environment requirements are higher and higher, eager to have a more refreshing, comfortable, environmentally friendly living and working environment. The use of environmentally friendly materials and end products can only protect the environment from pollution, but there is nothing that can be done to further improve the environment. As a result, a variety of functional coating additives continue to emerge, the application of these additives for human beings to create a healthier environment. At the same time, the use of functional additives makes the performance of coating products continue to improve, and give a lot of special performance. In recent years, building materials experts put forward a new idea to use building materials to increase the concentration of negative ions in indoor air, the use of negative ion additives in coatings came into being. Negative ion additives are mainly post-treated natural mineral powders, such as: Qi ice stone, electrical stone, Shenzhou Qishi, wheat rice stone, Guiyang stone and so on. After the coating is filmed, the water molecules in the air can collide with the negative ion additives in the coating through the void of the polymer membrane, ionization into hydrogen-oxygen root ions and hydrogen ions under the action of a strong electric field near the electrode of the negative ion powder particles. Hydrogen-oxygen root ions enter the air, attract water molecules in the air, form hydroxyl ions, that is, air negative ions, thereby increasing the concentration of negative ions in the air, to improve the environment. The continuous release of H3O2-negative ions by negative ion additives can be iridescale and encased around free-charged formaldehyde, ammonia, benzene and other harmful gas particles, so that they form large particle clusters and settle down, do not float in the air, no longer pose a danger to human health.
In addition, negative ion additives can remove odors in the air, because H3O2-can neutralize the air oxygen free fundamentals and oxidizing gases (corrupt odors), negative ion additives produced electric field can make organic odors in the electric field decomposition, thereby purifying the air. Negative ion additives also have a strong antibacterial antibacterial effect, which is different from antiseptics. The latter is to protect the coating itself or the paint film from bacteria and microorganisms, while negative ion additives are to the surrounding environment sterilization and antibacterial. Negative ion additives have elimination and inhibition effect on many strains, including E. coli, Staphylococcus acobacteria and mold, which is also the use of H3O2-clad or meso-effect, so that the bacteria lose the conditions for growth and reproduction. Although negative ion additives have been used in coatings, but in the negative ion release performance still needs to be further improved, the main means used at present is to use rare earth elements to resum negative ion additives.2.5 solvent-free wetting dispersantwater-based coating system will also appear in the traditional coating manufacturing and construction problems, but some in the traditional system has a good deblblishing performance, dispersion performance and substrate wetting effect of additives, is no longer suitable for the new water-based coating system. Taking deboulants as an example, the traditional descesting agent gradually weakens its ability to de bubble during the storage of coatings. In addition, the luster and clarity of the paint film often change significantly after the desiccant is added. A new anti-foaming agent technology has recently been developed, which maintains a certain degree of incompatibness necessary for de-foaming action without the reduction of de-foaming efficiency or surface defects. A similar problem occurs when using traditional substrate moisturizers, and the wetting efficiency decreases over time. This has also led to the development of a new polyether-modified sioxane surfactant, which has excellent stability over a wider pH range. Newly synthesized water-based polymers become more sensitive to the introduction of glycol and pigment wetting dispersant additives when applied to coloring slurry systems. This has led to the development of a new solvent-free wetting dispersion aid suitable for the development of a universal slurry free of substations. Pressure from environmental regulations has prompted paint manufacturers to develop more environmentally friendly coatings, and the performance of coatings should be maintained or even improved. In water-based coating systems, the use of de-foaming aids, dispersion aids and substrate wetting aids is essential. The main job of coating additive suppliers is to accurately predict the development trend of formulations and develop suitable products to promote technological progress.
2.6 preservatives such as microorganisms replace formaldehyde-like . Water-based coatings are a nutrient-rich system, from the beginning of production to the formation of paint film every link are faced with bacterial corrosion, especially in the environment of elevated ambient temperature, especially humidity and nutrient-rich environment, water-based coatings are faced with a large number of mold and bacteria reproduction and growth of serious challenges. Therefore, water-based coatings must be added fungicides to prevent microorganism damage to the coating, a small amount of addition can ensure that water-based coatings in the production and operation process, finished packaging storage, coating film is not subject to bacterial erosion. Foreign research and application of fungicides earlier, accumulated considerable experience, in technology ahead of domestic fungicides, coupled with accurate and sophisticated detection means, after-sales service and advertising offensive, so entered the Chinese market quickly after the use of manufacturers widely recognized, forming a brand effect. Based on China's huge architectural coatings market, the market for fungicides is growing rapidly. Even if only a few thousandths of the total formula is added, the overall market demand is considerable. At present, China's market demand for cheap, low-toxic and efficient fungicides has increased dramatically. In particular, the State Environmental Protection Administration issued a new green standard for water-based coatings, restricting the use of formaldehyde, previously used as a fungicide in water-based building coatings formaldehyde products were the first to be questioned. As a result, manufacturers are turning to other fungicides to replace formaldehyde products. In recent years, the domestic microbial anti-corrosion research in this regard has also carried out active research, domestic fungicides began to quickly push into the market, and in the application of continuous improvement of functional, environmental protection. Huake-981, Huake-108, Shanghai Institute of Light Industry JX-515, etc., have a place in the north and east China markets, driving the development of domestic fungicide technology.important direction of the future development of fungicides for building coatings is the use of nanotechnology. Now at home and abroad preservatives, anti-mold agents are mostly organic compounds, more or less have certain side effects on the human body, the development of nanotechnology so that antimicrobial technology has entered a new era. NanoTiO2, ZnO and other nanomaterials are non-toxic to the human body, antibacterial range, thermal stability is excellent. The action of nanomaterials is based on the photocatalytic reaction to break down organic matter and play an antibacterial role, in sunlight and the presence of air and water, the production of atomic oxygen and hydrogen oxygen freelance, can react with organic matter in bacteria, the generation of carbon dioxide and water, with anti-mold and antibacterial synthesis. Such as nano-antibacterial powder in coatings can be widely used in indoor walls, hospitals, food workshops and so on. Foreign countries have begun to develop silver antibacterial nanomaterials, this more effective antibacterial materials in a certain concentration of silver ions can effectively kill microorganisms. China also has the use of silver, silver-zinc and silver-copper, silver-zinc-copper inorganic antibacterial powder added to acrylic coatings to make antibacterial coatings research and development reports, antibacterial effect is excellent and economical.2.7 Promotes coating self-cleaning coating additives China's urban environmental pollution is increasing, including dust pollution, gas pollution is particularly serious. The facade of high-rise buildings, as one of the city's main scenic spots, is being eroded more and more seriously. Building exterior paint can beautify the environment and the room, but because of the traditional paint wash resistance is poor, the wall does not take long to become mottled land. According to the principle of self-cleaning of lotus leaves, the coating can form a microscopic convex appearance on the coating surface during the drying of the film by selecting and modifiing the inoranced particle material with special structure and shape. This microcosmic coating surface with a bumpy appearance allows dust particles to attach to the coating surface in a suspended state. Dust particles and coating surface force is greatly reduced, but also make water and coating surface contact angle greatly increased, conducive to water droplets on the coating surface, and at the same time, according to the principle of self-layering of the coating, hydrophobic substances into the emulsion, so that the coating drying process can be automatically layered, so as to add a layer of hydrophobic layer on the coating surface, is conducive to further reduce the dust particles and coating surface force and further improve the water to the coating surface angle. Eventually, the accumulation or adsorption of polluting particles under the wind and rain can be removed from the coating surface, to achieve the purpose of self-cleaning.3 Thehas been the most important factor affecting the development of the coating industry for nearly 10 years. With the development of economy, people's living standards continue to improve, consumers are more and more aware of the harm of paint to indoor air quality. As early as the early 1990s, coatings manufacturers in Europe and North America began to reduce volatile organic compound (VOCs) levels in water-based building coatings. To achieve this transformation, it is necessary to reduce the amount of film-forming additives (solvents and plasticizers) in coatings. However, reducing the amount of film-forming additives can have a significant negative impact on the performance of the coating. Therefore, how to meet the needs of customers with a strong sense of environmental protection has become a major theme of today's technology development, and thus by the industry's general attention..