Wood panel products most widely used

The most widely used wood panel products are particleboard, softwood plywood, hardwood plywood, medium density fiberboard (MDF) and waferboard. The most common adhesive is urea-formaldehyde resin (UFR). Phenol-formaldehyde resins (PFR) are second in volume and melamine-formaldehyde resins (MFR) are a distant third. Recently,... 

The first three chapters deal with particleboard, medium density fiberboard, hardwood plywood, and softwood plywood, the four most widely used wood panel products. Chapter four compares these products with other consumer products. Chapters five through seven explain the basic chemistry of formaldehyde with cellulose and wood components and provide a current understanding of the nature of liquid urea-formaldehyde adhesive resins. The next two chapters present new analytical methods that might become useful in the future. Chapters eight and eleven through sixteen explain the complex nature of the latent formaldehyde present in the products and its correlation to formaldehyde emission from wood products. Chapters fifteen and sixteen describe currently popular formaldehyde reduction methods. The last two chapters discuss the problems involved in reducing formaldehyde emission by regulating air levels or source emissions. 

The most common resin for lignocellulosic composites is urea formaldehyde. About 90% of all lignocellulosic composite panel products are bonded with UF [12]. UF is inexpensive, reacts quickly when the composite is hot-pressed, and is easy to use. UF is water-resistant, but not waterproof. As such, its use is limited to interior applications unless special treatments or coatings are applied. UF resins are typically used in the manufacture of products where dimensional uniformity and surface smoothness are of primary concern, for example, particleboard and medium density fibreboard (MDF). Products manufactured with UF resins are designed for interior applications. They can be formulated to cure anywhere from room temperature to 150 °C press times and temperatures can be moderated accordingly. UF resins (often referred to as urea resins) are more economical than PF resins and are the most widely used adhesive for composite wood products. The inherently light colour of UF resins make them quite suitable for the manufacture of decorative products. 

A separate mention is merited for a special molded hardboard product. These are made by a process in which either a fiber mat or hardboard panel is placed between two shaped platens and press-molded to a three-dimensional configuration. The most common resulting shape is a doorskin which resembles a wood panel door. The doorskins are bonded to wood frames to make an excellent, attractive, and relatively inexpensive door. This ftber/panel mol ding process is also used to make a wide variety of molded interior linings used in automobile manufacture. 

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