Abstract: chlorinated rubber coating is one of the most important anticorrosive coatings in China, which plays an important role in the national economic construction. However, due to its poor environmental protection performance, with the enhancement of People’s awareness of environmental protection, especially in the country issued a ban on the production of chlorinated rubber resin CCL4 today, the development of chlorinated rubber coatings is declining. The advantages and disadvantages of chlorinated rubber coatings were analyzed, and the future research emphasis and development direction of chlorinated rubber coatings were discussed.
With the continuous improvement of China’s economic level, the development of machinery industry is faster and faster, as the machinery industry must be anti-corruption materials field ushered in the development of the peak period. A large number of advanced performance, good quality of anti-corrosion products into the market. Chlorinated rubber coating with its excellent performance has been recognized by the majority of users in the fierce market competition to stand out. Since the 1960s, chlorinated rubber coatings have been widely used in shipbuilding, container, water conservancy, petrochemical industry and electric power construction as a supplementary coating for dental caries, the important guarantee function in the process of economic development. Relevant data show that chlorinated rubber coatings in the entire anti-corrosion coatings market share of only 2% to 3% . Many users do not have a deep understanding of chlorinated rubber anticorrosive coatings, especially a few manufacturers, in order to pursue economic interests, use other low-cost chloride compounds to replace the normal components in chlorinated rubber coatings, disrupting the market, it also affects the development of chlorinated rubber coatings. In order to promote the understanding of chlorinated rubber coatings to the majority of users of anticorrosive coatings, to promote the popularization and application of chlorinated rubber coatings, and to improve the development level of China’s coatings industry, the author, on the basis of long-term research, the basic properties, classification and application of chlorinated rubber coatings are introduced in this paper. It is hoped that it will be helpful to the users of anticorrosive coatings./n/nOverview of 1 chlorinated rubber coatings/nChlorinated rubber paint is made from chlorinated rubber resin which is produced from natural rubber or artificial synthetic rubber resin as matrix resin, and then mixed with corresponding auxiliary materials and solvents. Chlorinated rubber resin has high molecular saturation, no obvious polarity of molecular bond, regular structure and excellent stability. From the appearance, chlorinated rubber resin is white powder solid, non-toxic, tasteless, no irritation. Chlorinated rubber coatings are flexible and can be used with a wide range of pigments as primer, intermediate or Topcoat. One of the most used is as a topcoat for supporting the coating. By modifying chlorinated rubber resin with other resins, a variety of properties can be obtained or improved to achieve greater coating effect.
Introduction of properties of 2-chloro-rubber coating/n2.1 advantages of chlorinated rubber coatings/n2.1.1 excellent dielectric and weatherability/nAfter the chlorinated rubber coating film is formed, the molecular bond of the resin in the paint layer is firm, and the molecular structure is very stable. For this reason, chlorinated rubber paint layer has good weather resistance, for water, acid, alkali, salt, ozone and other media excellent resistance. The permeability of water and gas is only 10% of that of Alkyd. In practice, chlorinated rubber paint layer has strong resistance to aliphatic hydrocarbon solvent, product oil and lubricating oil. It can be used in damp environment to prevent mildew and has excellent resistance to cathodic stripping./n2.1.2 good adhesion, good compatibility with other kinds of coatings/nGreen rubber coatings used as primers have a considerable degree of adhesion to steel materials. As topcoat, intermediate paint can be used with epoxy, polyurethane and other varieties of primer, the effect is very high. The chlorinated rubber coating is easy to maintain. It can be repainted with chlorinated rubber coating or repaired with acrylic, solvent-based and anti-fouling coatings.
2.1.3 easy construction/nChlorinated rubber coating is a single component coating, film forming time is very short, construction speed is faster. Chlorinated rubber coating on the construction temperature requirements are relatively broad, 5 degrees below zero to 40 degrees above zero can be applied. The addition of diluent during construction is very little, even can not add diluent, thus reducing the volatile organic solvents, good environmental performance. Chlorinated rubber coating can be directly coated on the surface of concrete components, good alkali resistance. When it is used in assembly line, “Wet touch wet”method can be used to spray and greatly improve the production efficiency./n2.2 shortcomings and deficiencies of chlorinated rubber coatings/n2.2.1 chlorinated rubber coatings are dull in colour and lustre, poor in brightness, easy to absorb dust, and do not last long in colour and can not be used as decorative paints.
2.2.2 the heat resistance of the coating is very sensitive to water. In humid environment, the heat resistance is greatly reduced. The thermal decomposition temperature in dry environment is 130 °C, and that in humid environment is only 60 °C, which limits the application environment of chlorinated rubber coating, with the highest temperature not exceeding 70 °C.
2.2.3 the chlorinated rubber coating has low solid content and thin film thickness. In order to ensure the film thickness, it must be sprayed repeatedly, which affects the production efficiency./n2.2.4 chlorinated rubber coatings are less resistant to aromatic hydrocarbons and certain types of solvents, chlorinated rubber coatings can not be used as interior wall protection coatings in environments where there may be intolerant substances such as chemical plant piping, production equipment, storage tanks, etc. . At the same time, chlorinated rubber coating can not and animal fat and vegetable oil long-term basis./nDiscussion on environmental protection of chlorinated rubber/nThe base resin of chlorinated rubber coatings is produced by chlorination of natural rubber or synthetic rubber. The residue of CCL3 or CCL4 in chlorinated rubber resins and the escape of CCL3 or CCL4 during the production are the main pollution sources of chlorinated rubber coatings. In order to control the pollutant discharge and protect the environment, the Environmental Protection Department of our country issued the regulations of restricting and prohibiting the use of CCL4 in 2005 and 2010. Affected by this, many domestic enterprises have started to implement the R & D and production projects of environmental-friendly chlorinated rubber resin, in order to improve the environmental performance of chlorinated rubber coatings, to meet the new market demand.
Development trend of chlorinated rubber coating/n4.1 study on the flexibility of paint film/nChlorinated rubber coatings are widely used in the anticorrosion of metal products. Because the volume of metal products will change obviously when the temperature changes, in order to ensure that the film quality is not seriously affected when the substrate expands and contracts, the chlorinated rubber coating must have good flexibility, in order to reduce the stress of the substrate when the large-scale expansion. At present, the main method to improve the flexibility of chlorinated rubber paint is to add chlorinated paraffin. From the experimental data, when the total amount of chlorinated paraffin added to chlorinated rubber resin reached 20% , the film flexibility can reach 1 ~ 2 mm.
4.2 research on modification techniques
In order to improve the performance of paint film and expand the application scope of chlorinated rubber paint, researchers have done a lot of research on the modification of chlorinated rubber paint. By using chlorinated rubber in combination with alkyd, epoxy ester, epoxy, coal tar pitch, thermoplastic acrylic acid and vinyl acetate copolymer resin, a composite coating was prepared, in the film flexibility, weather resistance and corrosion resistance and other aspects have made significant progress, promoting the development of heavy anti-corrosion coating industry.
4.3 study on solid content of coatings/nChlorinated rubber coatings have low solid content and thin film thickness, so it is necessary to increase the times of painting and affect the production efficiency to meet the requirements of film thickness. In order to solve this problem, it is necessary to improve the solid content of paint. Because chlorinated rubber coating is difficult to water-borne, in order to ensure the performance of the construction can only be reduced solid content. At present, the solid content of chlorinated rubber coating is between thirty-five to forty-nine per cent, and the solvent content is high, which affects the environmental protection performance of the coating. The main methods to improve the solid content of chlorinated rubber coating are to adjust the chlorine injection time and control the reaction temperature.
Prospect of 5 chlorinated rubber
The proportion of chlorinated rubber coating in heavy-duty anticorrosion industry is not large. With the increase of national environmental protection requirement, the development space of chlorinated rubber coating is further compressed. From the use of performance, chlorinated rubber coating still has a strong vitality. Therefore, it is very important to improve the environmental protection characteristics and the overall performance level of chlorinated rubber coating, and to enhance its market competitiveness to meet the requirements of modern society. Ship building, non-standard container, hydraulic power engineering, chemical industry, navigation mark manufacturing and traffic facilities are the main development direction of chlorinated rubber paint. In the above areas, chlorinated rubber has strong applicability. With the development of China’s economy, the above-mentioned fields will surely usher in a new peak period of development, thus bringing a broader market space for chlorinated rubber coatings.
6 closing remarks/nTo sum up, chlorinated rubber coating coating excellent performance, is one of the important anti-corrosion coatings. However, due to environmental protection and other reasons, chlorinated rubber coatings market situation is more severe. Increasing solid content and improving environmental performance are the main development direction of chlorinated rubber coatings in the future. In addition, it is an important means to improve the comprehensive performance of chlorinated rubber coating through modification research, which can meet the market demand and develop the application field. With the further development of China’s industry, the role of chlorinated rubber coatings in shipbuilding, chemical industry, Water Conservancy and power facilities will be further strengthened to improve the adaptability and performance of chlorinated rubber coatings in the above-mentioned fields, it is an important task for chlorinated rubber coating enterprises in the future.