VOC Regulations and High-Solids Acrylic Coatings
0 Introduction
Currently, there is a great deal of global concern about the earth’s environment and therefore many restrictions have been set to protect the environment, so that many products and raw materials have to face major innovations, the standard of living of human beings continues to improve while the deterioration of the natural world is becoming more and more serious. The main implementation steps to control environmental pollution are 66 rulemaking and CAA. For the paint industry, the main (actually the only) air quality related to volatile organic compounds (vOc). Increased consumption of coatings and solvents has resulted in fairly stringent regulations for vOc control, and environmental, economic, technological, and competitive pressures have created the need to develop less polluting but more economical coating systems.
1 VOC
In Europe, on March 11, 1999 by the Steering Committee (Solvent Emissions Steering Committee SED) 1999/13/EC on “in certain acts and facilities due to the use of organic solvents and volatile organic compounds produced by the emission limits,” which defines VOC as any organic compound that has a vapor pressure of 0.01 Kpa or higher at 293.15 K, or that has a vapor pressure of 0.01 Kpa or higher at 293.15 K, or that is not present in the paint. higher, or an organic compound that has such volatility under special conditions of use. Solvents and volatiles are not a permanent part of the coating, they volatilize and lose and pollute the environment due to photochemical reactions with nitrogen oxides in the presence of ultraviolet light (sunlight) to form fumes in the atmosphere that contain ozone as well as aldehydes (mainly), ethyl nitrate peroxide and small particles, collectively referred to as oxidants, which all have a negative effect on health. Ozone damages the lungs, irritates the eyes and may reduce immunity and is a potential greenhouse gas. The resulting smog can last for days and travel long distances. The costs of air pollution due to voc emissions include negative impacts on human health, reduced crop yields, accelerated aging of raw materials, and destruction of ecosystems. The reaction steps are described in more detail below.
It has been reported that the paint industry is responsible for 38% of the VOC emissions in Europe, where in 1995 about 3 million tons of paints were produced for a wide range of applications. This resulted in a staggering 100,000 tons of VOCs being produced in a single year.
2 Increasingly Stringent Environmental Regulations Promote the Development of Environmentally Friendly Coatings
In Europe, different restrictive regulations have been established at different times, and environmental requirements are becoming increasingly stringent. The coatings community is facing major challenges. Increased demands for product-specific properties and VOC pressures have accelerated the development of new technologies that can satisfy customer requirements, and the response to these environmental control regulations has been so strong that resin manufacturers have expended considerable effort to meet the regulatory needs of the coatings industry. A number of low or non-polluting raw materials for coatings have been developed and introduced into the market to maintain the ecological balance. They are
1) High solids solvent based coatings
2)Solvent free or 100% solids based coatings
3)Solvent-free liquid coatings
4)Electrophoretic coatings
5) radiation curing coatings
6)Water-based coatings
7)powder coatings
8) non-aqueous dispersion (NAD) coatings.
They replaced traditional solvent-based coatings to meet increasingly stringent governmental restrictions to avoid pollution of the environment (Fig. 1)
High-solids coatings of the alkyd, vinyl compound, acrylate, polyester, epoxy, or polyurethane type, typically containing more than 70% solids, have been developed to meet pollution restrictions and reduce energy consumption. Despite significant advances in waterborne systems and powder coatings, solvents are still indispensable in many applications. Thermoset acrylic resins are discussed below because the thermoset acrylic resins available today not only have the typical acrylic resin properties, but also have the ability to be used in a wide variety of applications.
thermoset acrylics are discussed below because they are now available with not only typical acrylic properties, but also higher work solids and better chemical resistance than thermoplastic acrylics.
3 Thermoset Acrylics
Acrylics are commonly used in coatings as a Class II resin due to their unique chemistry, large selection of monomers, and the ability to be designed with a variety of polymerization methods and flexibility.
properties. The ability to obtain different copolymers by using two or more monomers allows for new products with unique and useful properties, which depend on the composition and ratio of the monomers, as well as the method of preparation.
The acquisition of properties depends on the composition and ratio of monomers, as well as on the method of preparation. In the development of high solids and high performance coating systems, it is necessary to reduce the relative molecular mass of the base material and to develop and build a zwitterionic system. Critically, thermoset acrylics should be a heteropolymer in which one component provides stiffness, another provides flexibility, and a third component contains reactive functional groups that can be used for cross-linking. Other monomers can sometimes be introduced into the polymer backbone to enhance certain specific properties. They may be self-reactive (e.g., resins containing glycidyl and hydroxymethyl groups) or have potentially reactive (e.g.
