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Technology and direction of domestic architectural coatings

technology and direction of domestic architectural coatings

April 1, 2005

I. huge market demand and coating hydration

with the sustainable development of China's economy, architecture and its supporting decoration industry have also entered an unprecedented era of rapid development. In particular, the new mandatory standards issued by the state, such as "interior wall coating", "wood coating", "expression method of building color", provide very favorable conditions for the production of environment-friendly coatings. The status of architectural paint as the main decorative material of interior and exterior walls of buildings is being established. However, the development of high-performance coatings, especially exterior wall coatings, lags behind. At present, the application rate of paint in building exterior wall decoration materials in China is quite different. The requirements of the 2010 development plan outline of the Tenth Five Year Plan for the national chemical building materials industry; The application rate of architectural coatings for exterior walls reached 35% in 2005 and 60% in 2015. Even if a little grease is used from 2000 to 20, the service life of aramid bushing will be reduced. The consumption of exterior wall coating will reach 1.05 million tons in 15 years, and it should reach 1.8 million tons by 2015. At present, foreign brands account for a high proportion in the domestic high-end coating market, especially in the exterior wall coating market. However, the quality control of foreign coatings, especially the pollution and weather resistance index of exterior wall coatings, is far lower than the actual requirements of our country (such as: artificial aging, foreign indicators ≥ 250 hours; China is ≥ 600 hours). Therefore, the market demand for high-quality coatings, especially exterior wall coatings, is huge

Chinese people regard architecture as a long-term plan and require that architectural decoration be durable. In order to greatly improve the application rate of architectural exterior wall coatings in China, it is required that the performance of coatings should be improved by a leap, that is, a good combination of high decoration, strong stain resistance and high durability, and meet the requirements of environmental protection and sustainable development of energy saving, pollution-free and pollution-free. From the perspective of decoration, stain resistance and durability, solvent based coatings are relatively easy to meet the requirements, but it is difficult to meet the requirements of air permeability and environmental protection. From the perspective of environmental protection, an important development direction of coatings is hydration. However, the weatherability and stain resistance of water-based coatings are usually difficult to compare with solvent based coatings. This method of analyzing the iron content in lubricating oil is a difficult technical problem. As a building coating, its coating base is mainly hydrophilic materials such as cement, concrete and gypsum board. As a base building, in a natural state, there must be a process of water absorption and drying. Obviously, the affinity and permeability of the building coating to hydrophilic materials are its essential basic performance requirements, and the characteristics of its on-site construction are more clear about the requirements of pollution-free environmental protection. These two points are the strengths of water-based coatings. Therefore, the key to the high performance of architectural coatings is to realize the high performance of water-based coatings

II. Progress in high-performance technology of waterborne coatings

1. New progress in lotion synthesis technology

the most basic determinant of coating performance is film-forming substances. The most basic determinant of the high performance of waterborne coatings is naturally the lotion binder of film-forming substances. In order to realize the high performance of water-based coatings, the main technical progress of water-based coatings at home and abroad in lotion synthesis technology in the past two to three years is as follows:

soap free lotion polymerization technology - provides a technical and basic material basis for fundamentally improving the water resistance of latex coatings

self crosslinking technology provides a reliable technical way to improve the coating film hardness and increase its stain resistance and aging resistance

core-shell structure and interpenetrating technology provide a strong guarantee for reconciling the contradiction between low-temperature film-forming property and high-temperature stain resistance of latex coatings and greatly reducing the incorporation of organic volatiles in latex coatings

a variety of functional group improvement technologies, such as silicone polyurethane and other monomer modified acrylic polymer lotion and fluorosilicone lotion. The emergence of a large number of high-performance lotion, provides cementitious materials for the preparation of coatings with different performance requirements, and provides a special marine water environment for the development of corresponding high-performance coatings, making it impossible for people to collect and treat such a large amount of scattered garbage in a centralized manner as on land. In the past two to three years, these technologies and products have rapidly spread through foreign companies and domestic joint ventures to domestic sales companies and production companies, forming a technological diffusion and gradually expanding their applications

2. Development and application of high-performance additives, high dispersion technology and equipment

film forming binder is the basic material basis of coatings. Appropriate application of additives is the key technical point for preparing coatings with excellent performance. High dispersion technology and equipment are the process guarantee for the preparation of high-performance coatings, which are the three main technical links of coating product manufacturing

there are many kinds of coating additives, which are high-tech confidential fine chemical products, and their production and application involve a wide range of technologies. In the past, due to the limited production technical conditions of domestic coating manufacturers, this was not paid enough attention to or difficult to pay attention to. In recent years, great changes have been made: a large number of domestic and foreign professional additive production companies launched a large number of new additives products, and strengthened technical services to coating manufacturers in order to sell their products. From the perspective of paint technology development and service, we are also sparing no effort to publicize that paint additives should be used properly and accurately. We should not distinguish good from bad with simple price and dosage, but with the principle of just right, which requires careful research and experiment. The product development test of the auxiliary manufacturer. Due to the continuous innovation of different film-forming substances and a large number of additives, the low age of opening a paint factory with one formula has become a thing of the past

Another important component of paint is pigment. With the widespread use of ultra-fine fillers, some new dispersion technologies and equipment have been applied in coating production. The most typical is that the high shear emulsification system replaces the high-speed mixing dispersion grinding adjustment process commonly used in paint production in the past, and the continuous flow process replaces the intermittent process. The adoption of new processes and equipment greatly converts the elongation into the tensile value, which improves the dispersion of materials that are crucial to paint preparation. While improving product performance and quality assurance, it greatly reduces the loss of materials and the burden of wastewater pollution treatment caused by multiple cleaning of previous processes

3. Fluororesin and its coating technology

fluororesin forms special protection for the carbon chain in fluorocarbon polymer due to the extremely high bond energy of fluorocarbon bond formed by the strong combination between fluorocarbon atoms in its molecular structure and the spatial effect of fluorocarbon bond, so it has extremely unique excellent mechanical properties and strong anti-aging performance. Therefore, the plastic made of fluororesin is called "plastic king". The coating made by using this unique characteristic of fluororesin is known as the non stick coating on the surface of non stick pots and non stick oil range hoods. The most important analysis is to use its surface energy characteristics of being free from oil and water. The disadvantage caused by its non stick is that it is difficult to bond and coat, so it should be coated by high-temperature baking. The use of fluororesin as a coating for architectural coating began in the United States and was coated by high-temperature baking. The curtain wall made of aluminum alloy plate has excellent stain resistance and aging resistance, but it is extremely expensive and cannot be used for on-site construction. The Japanese later transformed it into a two-component reaction curing coating that can be painted at room temperature, which can be used for on-site construction. This coating was developed in China in the past few years, and it was called fluorotopcoat and put into the market. However, because it is prepared with oily toxic solvents, which pollutes the environment, and the coating is airtight, and it is a two-component product, which is inconvenient for on-site mixing and construction. Therefore, in recent years, it has focused on the development of single component and waterborne. The author and the research team have made important research and development achievements in the development of water-based chemicals, applied for Chinese patents, and obtained independent intellectual property rights. After the introduction of this technical achievement, there has been a great response. In the past year, the process of developing water-based fluororesin and fluorosilicone resin coatings has been significantly accelerated

4. Application of nanomaterials and nanotechnology

nanomaterials and nanotechnology is a high-tech concept in which the recent mixed hype has entered the common topic. Nanotechnology of nanomaterials does have its magic. Nanoparticles have small-size effects, macro quantum tunneling effects, etc. only when these effects are really brought into play, can they really be called "nano effect", and its magic is now. The nano effects that can be used for coatings are mainly small size effect, large specific surface area, interface effect and quantum effect

small size effect - such as titanium dioxide and iron oxide FeOx, commonly used pigments in coatings, are usually regarded as fine and ultra-fine powders with particle sizes in microns( μ m) The finer the grade range, the higher the hiding power. According to the information, the particle size of TiO2 reaches the half wavelength of the shortest wavelength visible light, i.e. 0.2 μ At the level of about M, its coverage is the highest. When the particle size is finer to nanometer (nm) (1 ~ 100nm, 1000nm=1 μ m) , which is completely transparent to visible light and becomes completely invisible. The same is true of FeOx. In addition, SiOx has no obvious absorption and reflection of ultraviolet light at the micron level, but it has obvious absorption and reflection at the nanometer level. These characteristics can be used as inorganic transparent pigments for coatings, which greatly improves the aging resistance of colored coatings

interface effect of large specific surface area - the particle size of powder material ranges from several microns to several nanometers, and the specific surface area increases from about 1m 2/g to 450m 2/g. The proportion of the number of atoms in the surface area of each powder increased from < 1% to > 80%. This change will greatly improve the surface activity of the powder particles, greatly improve the binding force with the film-forming cement in the coating, and there will be a strange phenomenon that small molecular inorganic fillers simultaneously harden and toughen the polymer organics (generally, the toughness will be reduced when the micron level fillers harden). Thus, the film performance of the coating can be greatly improved

quantum effect - when the powder enters the nanometer level and the particle size is as small as a certain value, the atomic bond valence changes, the electronic energy level changes from continuous to discrete, and the energy gap of the molecular orbital energy level becomes wider and quantized, which will lead to the light quantum absorption and catalytic properties of some powders. The so-called nano materials catalyze and sterilize under the action of light, which is the embodiment of this characteristic. Therefore, clean coatings that sterilize and degrade organic matter can be made

5. The integration of architectural coating and waterproof function

due to the improvement of the requirements of water resistance, pollution resistance and durability of architectural coating and the increasing attention to the waterproof problem of building facade, the integration of architectural coating and waterproof function is becoming increasingly obvious. In particular, with the improvement of building thermal insulation requirements, the wide use of internal and external insulation layers, and the increasing dependence on coatings for waterproof and decorative protection of insulation layers. Due to the significant improvement of coating durability in recent years, confidence in the use of waterproof coatings in construction has greatly increased; In addition, the development of coating technology has promoted the development of a number of coated waterproof materials for cement concrete, which has made great progress. In addition, the requirements for non-toxic, water-based and light colored waterproof materials have been improved, making rigid waterproof flexible materials highly elastic in building waterproofing, especially the facade waterproofing and building decoration coating are almost integrated. This trend is expanding indoors, on the roof and underground

III. the future of high-tech portfolio innovation is promising

in the past one or two years, in the process of realizing the hydration and high-performance of architectural coatings, the development of the above-mentioned technical situation has accelerated, and the technical development level of architectural coatings in China has reached a new level. Difference

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