Melamine Impregnated Paper : Impregnation resin
Impregnation resins for décor-paper consist of either melamine-formaldehyde (MF) or urea-formaldehyde (UF) pre-polymers in aqueous solution. Such resins are living chemicals with a limited shelf life of 1-3 weeks. Prior to use the resins are blended with water to adjust the viscosity, and at the same time catalysts and additives are added. In a typical two-stage impregnation process the paper core is first impregnated with a UF resin to fill all the voids to accomplish good internal tear strength. After the drying of the core resin the surfaces are coated in a second step with the MF resin thereby achieving superior surface characteristics such as hardness, scratch resistance, and vivid colors. After the MF resin is dried likewise the paper can be cut to size and stored for several months before laminated onto particleboards and MDF for furniture and flooring.