Formaldehyde Release Reduction - Key for Amino-Plastics Industry to Save Energy and Cut Emissions     

Both urea-formaldehyde molding compound and melamine powder (melamine-formaldehyde compound) belong to amino molding plastics. Urea-formaldehyde molding compound is used in the manufacture of household electrical appliances, switches, sockets, caps and other daily necessities, while melamine powder is used to produce heat- and water-resistant tableware and high-end voltage devices.
   As China's output of urea-formaldehyde molding compound and melamine powder keeps rising, thereafter the environmental problems are also becoming more and more serious, such as dissociative formaldehyde releases and the usage of raw materials.
   The three main raw materials for urea-formaldehyde compound resin are formaldehyde, urea and methenamine, while the two main feedstocks for melamine-formaldehyde compound resin are formaldehyde and melamine. Since the raw materials of both resins contain formaldehyde, the reduction of free formaldehyde during the production of resins becomes the key process to reduce releases of formaldehyde for urea- formaldehyde molding compound and melamine powder.
   Zhejiang Wanan Plastics Co., Ltd. produces urea-formaldehyde compound resin by synthesizing urea formaldehyde resin and melamine-modified urea formaldehyde resin, which transforms the excess formaldehyde into resins as much as possible. This process has advantages of reducing pollution on the atmosphere, protecting the health of workers, greatly cutting residual formaldehyde in urea-formaldehyde molding compound.
   In the production of melamine-formaldehyde compound resin, the company uses a new melamine-formaldehyde resin synthesis process, which covers raw material dissolution, aggregation and termination. The synthetic resin produced by this method shows good stability. And under this method, more inorganic additives and fillers could be added in processing melamine powder, which reduces consumption of per unit melamine-formaldehyde compound resin. Products made from these resins contain less formaldehyde residues, and have their heat resistance and impact strength substantially improved.
   According to the test results by Zhejiang Wanan, the free formaldehyde content is below 0.5% under both processes, which signals significant effect in emission cut. All the free formaldehyde is fully reused to cut costs.
   To reduce use of formaldehyde feedstock, while reducing the emissions of free formaldehyde is undoubtedly a way out for the amino plastics industry to save energy and cut emissions.
   Related experiments also found that it's workable to add inorganic minerals (like talc powder and calcium magnesium carbonate powder) without affecting the quality of urea-formaldehyde molding compound and melamine powder. This not only helps lower production costs, but also helps reduce formaldehyde feedstock consumption by 15%. Assuming a combined annual output of 800 000 tons for urea-formaldehyde molding compound and melamine powder used in China in 2010, the processes could help save about 200 000 tons of raw materials, a quite significant amount.