Today's
Packaging coating products are widely used in the petroleum industry, coking industry, organic synthetic chemical industry and other sectors as raw materials, more and more varieties, the scope of application is also expanding, the material industry has become an important independent production industry in the chemical industry department.
China's current coating production is about 2 million tons, of which industrial coatings account for 60%. In recent years, demand will increase at an average rate of 3.4%.
In the early 1990s, the developed countries in the world carried out a “green revolution”, which was a challenge to the paint industry, and promoted the development of the paint industry to make great strides toward “green” paints. In the next decade, waterborne coatings will replace solvent-based coatings and become the market's main product.
At present, the direction of coating research: First, the automation of coating applications, especially the automation of product painting; Second, the development of environmentally friendly coatings; The third is to add new components, so that the coating in the coating after the occurrence of new chemical changes It forms a coating film and converts a thin coating that can only be obtained in one construction into a thick coating. The number of coating layers will also be reduced to a simple construction by the tedious multi-passage. The drying process of the coating film will also be shortened by various physical and chemical reactions.
Development of Waterborne Coatings
As the superiority of waterborne coatings is outstanding, the application of waterborne coatings in the field of general industrial coatings has been expanding for the past decade and has replaced many commonly used solvent-based coatings. With the increasingly stringent restrictions on volatile organic compounds and toxic substances in various countries, as well as the optimization of resins and formulations and the development of suitable additives, waterborne coatings are expected to be used in metal anti-rust coatings, decorative coatings, architectural coatings, etc. Solvent-based coatings will make breakthrough progress. In waterborne coatings, latex paints have an absolute advantage. The research results of latex paints account for about 20% of all paint research results. There are the following aspects:
● The study of film formation mechanism is mainly to improve the performance of coating film.
● Research on construction applications. In recent years, emphasis has been placed on the development of strong adhesion materials and fast-dry tomb materials and the development of hybrid resin adhesives. Typical aqueous latex polymers have poor adhesion to hydrophobic substrates such as plastics and poorly purified metals. To improve latex adhesion, attention must be paid to the design of the latex polymer and formulation to make it as close as possible to the surface of the substrate and to carefully select the appropriate coalescent to reduce the critical surface tension of the water to accommodate critical critical surface tensions. Commercially available plastics. Newly developed polymer emulsions are easy to coalesce, so that a small amount of coalescent agent can also form a good film, and it has been widely used in furniture, machinery and various plastic products. The newly developed latex mixture compensates for the respective deficiencies of water-reducible alkyd or rigid thermoplastic latex, and has been solved for miscibility and stability through formulation design.
The problem of poor sex.
● Waterborne polyurethane coatings are a rapidly growing class of waterborne coatings. In addition to its inherent high strength, abrasion resistance and other excellent properties, the polyurethane coating has no pollution to the environment and has a low risk of poisoning and ignition. Due to the presence of urethane and urea bonds in the water-based polyurethane resin, the flexibility, mechanical strength, abrasion resistance, chemical resistance, and durability of the waterborne polyurethane coating are all excellent, with European, American, and Japanese daily averages. Think of it as a high-performance, modern coating variety and research and development.
The rapid development of powder coatings
In the coatings industry, powder coatings are a category that develops rapidly. Due to the serious air pollution in the world, the environmental pollution regulations of various countries have become increasingly stringent. Therefore, powder coatings without solvent, 100% conversion into films, and comprehensive properties of protection and decoration are rapidly developed due to their unique economic and social benefits.
The main varieties of powder coatings are epoxy, polyester, acrylic and polyurethane. In recent years, aromatic polyurethanes and aliphatic polyurethane powders have been remarkable for their excellent performance.
High solids coating development trends
With the strengthening of environmental protection measures, high solids coatings have developed rapidly. Among them, the application of amino, acrylic and amino-acrylic coatings is more common. In recent years, U.S. Mobay has developed a new type of top coat for coating lines for
Metal Packaging. This high solids, one-component polyurethane-modified polymer system can be used on rigid and flexible substrates with excellent acid resistance, hardness, and kneadability of the pigment. The use of aliphatic polyisocyanates such as Dsemodur N and polycaprolactone can produce polyurethane coatings with up to 100% solids. This paint has excellent performance and simple construction methods.
Progress of Photocurable Coatings
Photocurable coating is also a solvent-free and energy-saving coating. It was originally mainly used for wood and furniture, and is now widely used in the coating of wood and plastic packaging products. In Europe and developed countries, the photocuring market has great potential and is favored by large companies. Mainly to meet the needs of flow operations, the United States now has about 700 large-scale light-cured coating lines, Germany, Japan and other countries about 40% of the wood or plastic packaging using light-cured coatings. Recently, a urethane-acrylic photocurable coating has been developed, which is produced by dissolving a urethane acrylate oligomer with a reactive diluent (photopolymerizable acrylic monomer). It not only maintains the characteristics of acrylic resin photocurable coating, but also has particularly good flexibility, adhesion, chemical resistance and abrasion resistance.
The Situation and Development of Several Special Coatings
1. Antifouling coating
In recent years, the Sigma company in the Netherlands has successfully developed a new tin-free antifouling coating. Its self-polishing property is the same as that of existing tin-containing antifouling paints, but its anti-cratering and anti-cracking properties are greatly superior to other tin-free ones. Antifouling paint. Recently, Kansai Coatings of Japan has newly developed a non-toxic, non-organic tin and cuprous oxide called Captain.
Crystal's antifouling paint. This paint has
Effectively prevent the contamination of the packaging and lasts for up to 5 years.
2. Anti-corrosion coating
Foreign countries attach great importance to the development of long-term anti-corrosion coatings. The main varieties include inorganic zinc-rich paint, epoxy asphalt, vinyl resin, high-density chlorinated rubber, solvent-free epoxy polyamide, solvent-free epoxy mortar, and SPGuard coatings. The development of anti-corrosion coatings in China is fast: for example, the epoxy coal-tar anti-corrosion coating has been successfully developed by Shaanxi Yuanyuan Chemical Co., Ltd. The coating has strong adhesion and can be directly brushed on steel with rust layer, and the anti-corrosion effect is good; organic titanium coating As a high-tech anti-corrosion coating developed by the Institute of Jilin Chemical Industry Co., Ltd., the corrosion resistance of this non-toxic organic titanium coating has reached the level of similar foreign products, can be used in chemical, marine and other fields of anti-corrosion equipment.
3. Cathodic electrodeposition coating
Such coatings have developed rapidly abroad and have made many new developments. The most representative of these is the development of thick-film cathodic electrophoretic coatings, low-temperature curing and color cathode electrophoretic coatings. Thick-film cathodic electrodeposition coating is a new type of cathodic electrodeposition coating developed by PPG of the United States. Its performance is excellent. Color cathodic electrophoretic coating was developed by Kansai Paint Co., Japan. It is based on epoxy resin, cross-linked with special isocyanate, and accompanied by a third component acrylic resin, which can be uniformly deposited in the electrophoresis to form a composite coating film. This technology allows colorization of epoxy-based cathodic electrodeposition coatings and also improves the weatherability of coatings. The future development direction of cathodic electrodeposition coating is: thick-film cathodic electrophoretic coating will solve the problem of viscoelasticity control of the film deposited during electrophoretic coating and the viscoelasticity of the film during the baking process, making the film thicker and smoother in appearance. The development of low temperature curing cathodic electrophoretic coating is development
Curing temperature is 130 °C -140 °C low temperature curing type, and to maintain corrosion resistance and other properties unchanged, so that it can be used for plastic, metal and other packaging, save energy and reduce pollution. Edge rust-proof cathodic electrophoretic coating requires reducing the flowability of the coating film and improving the edge coverage of the coating to improve the corrosion resistance of the edge of the cathodic electrodeposition coating. China should focus on the development of thick-film cathodic electrophoretic coatings with a thickness of 30-40 micron, salt spray-resistant 1000 hours, and ordinary cathodic electrophoretic coatings resistant to salt fog for more than 720 hours.
Other trends in development
In order to meet the needs of the improvement of the performance of coating products and the increase of varieties, the performance of the desired pigments should also be continuously improved. Mainly organic pigments, such as azo-based, phthalocyanine-based, and Lanthanide pigments with excellent light and solvent resistance, will be more widely used.
The use of supplementary materials in coatings has become increasingly important for the development of coatings. If UV absorbers are used in coatings, lightfastness can be improved; antioxidants can improve aging resistance. With the development of waterborne coatings, the variety of wetting agents will continue to expand; in the use of UV drying coatings, the use of light curing agents. These auxiliary materials will be more widely used in the future.
The application of computers in the coatings industry can optimize coating formulations, large-scale industrial production, and the design of production facilities, and can quickly solve the technical and management problems that arise in the research, production, application, and sales of coatings. With the increase in the demand for coatings and the variety of products, the paint production process also needs continuous improvement. The general trend of improvement is to further simplify the process, increase productivity, and achieve continuous and automated production. In the future, jet technology, thyristor technology, nanotechnology, etc. will be widely used in the paint industry, so that the degree of automation of production reaches a new level.
