Nuremberg -- Polyurethane (PU) coatings and adhesives formulated with Bayer raw materials are environmentally compatible yet highly efficient coating solutions that make a significant contribution to the advancement of climate protection, with the reduction of solvent emissions playing a major role.

With their low content of volatile organic compounds (VOC) the coatings easily satisfy the increasingly stringent requirements of solvent regulations. However, polyurethane systems also help to conserve resources and energy. When used in anti-corrosion applications, for example, they also help finished goods to retain value for an extended period.

Environmentally compatible and efficient corrosion protection

A current example is the protection of steel structures with two-component INSERT INTO [lzx].[dbo].[tb_new]([id],[type],[title],[source],[personal],[image],[contents],[time],[number]) VALUES (2K) topcoats formulated with products from the Desmophen NH and Desmodur N lines. Compared with conventional systems, formulations based on polyaspartic raw materials contain roughly 40 percent fewer VOC. In the specific example of the BayArena soccer stadium in Leverkusen, Germany, this corresponds to savings of approximately 2,000 liters of solvent. Depending on the formulation, the VOC content can even be reduced to zero.

The coatings can be applied to a coating thickness of as much as 400 micrometers in a single step. This enables one layer of the previous three-layer coating structure to be eliminated, reducing application costs and boosting efficiency. Furthermore, the complete process - from application of the primer until the topcoat is dry - takes just six to eight hours at room temperature. This represents a clear productivity advantage over the use conventional coatings, for which the entire process including drying takes 24 to 36 hours. This enables the coated parts to be used without restriction much sooner. Reduced downtimes increase the cost effectiveness.

Polyaspartic topcoats already help to keep wind turbines operational today, such as by protecting the steel towers against corrosion. With this development, Bayer MaterialScience is also helping to protect the climate through the use of renewable energies.

Wooden towers for wind power generation

Who says that the masts of wind turbines always have to be made of steel or concrete? TimberTower GmbH is taking a different approach here. The company uses a composite system of cross-laminated wooden panels for the towers. The material is held together with a certified polyurethane adhesive from Purbond AG and coated on the outside with PVC sheeting. Bayer MaterialScience supplies the raw materials for the environmentally compatible adhesive - a solvent-free, 100 percent solids system. The PU adhesive technology thus presents entirely new growth opportunities involving the use of the renewable raw material wood for power generation from renewable energy sources. The energy saved working with wood rather than producing steel is one of this projects key environmental advantages.

Compared with a steel solution, the wooden towers will be roughly 20 to 30 percent less expensive to manufacture. The individual parts are assembled on site to facilitate easy shipment in containers. Steel towers, on the other hand, must be shipped as oversized loads, which are associated with additional costs. Tower heights of more than 100 meters should be possible, even in relatively tight spaces. One test tower has already been built; a tower 100 meters tall is scheduled to be built this year.

Economical and sustainable production of coated plastic components

Efficiency gains are also an objective when it comes to the coating of plastics. DirectCoating technology is a new production method with which coated plastic components can be manufactured sustainably and economically in an integrated process. Following the production of the molded part, the coating step is performed while still on the injection molding machine. This offers clear productivity advantages versus the conventional method. The component manufacturer does not need to install a coating line, thus saving investment and operating costs as well as energy.

DirectCoating technology is also good for the environment. Polyurethane coatings that are completely free of solvents can be used, and the method produces no overspray that would then require disposal. This technology, which is currently in the introductory phase, can be used to produce plastic components for exterior and interior applications, such as for the automotive industry.