Melamine Impregnated Paper : Paper impregnation
To attain attractive and durable surfaces for furniture and flooring particleboards and MDF are usually thermo-fused with printed or solid color paper. Such décor-paper is saturated with melamine and urea resins in specially designed impregnation treaters.
Usually, such treaters have two sections, one to fill the core and the second to coat the surface. Both sections consist of an application unit, and a drying stage. This process requires that the resin be uniformly distributed within the paper core and on its surface. This is achieved by careful adjustment of the resin viscosity and line speed, and through the obligatory use of specially designed additives. After drying the impregnated papers can be stored for several months before being hot-pressed onto boards. During hot-pressing or thermo-fusing the resin in the paper softens sufficiently to bond with the substrate. Subsequently the resin cures to become a very hard and durable solid that protects the décor paper. Release agents support the clean separation of the laminated board from the press plate. Curing speed and completion is determined by the right choice of catalysts. All additives and catalysts are added to the resin prior to the impregnation process.