Medium density fiberboard particleboard, hardwood plywood

Approximately one million metric tons of urea-formaldehyde resin are produced annually all over the world. More than 70% of this urea-formaldehyde resin is consumed by the forest products industry. The resin is used in the production of an adhesive for bonding particleboard (61% of the urea-formaldehyde used in the industry), medium-density fiberboard (27%), hardwood plywood (5%), and as a laminating adhesive (7%) for bonding furniture case goods, overlays to panels, and interior flush doors, for example. 

Particleboard, 62% medium density fiberboard, 19% hardwood plywood, 5% glass fiber roofing mats, 4% molding compounds, 3% miscellaneous, 7%... 

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 single largest end use for hardwood plywood is interior wall panels, generally 3-ply and 1/4 and thinner, and frequently machined with decorative v-grooves. Furniture, cabinets, door skins and a number of specialties complete an array of end use products. Many of the non wall panel products can be characterized as being industrial panels and are of 5 or more ply veneer core, 3-ply particleboard core, or 3-ply medium density fiberboard (MDF) core construction. Broad end use patterns indicate that interior wall panels represent approximately 55% of total hardwood plywood consumption. Furniture, cabinets, and fixtures represent about 30%, and door skins and specialty products about 15% (2), Potential sources of formaldehyde in two of the more typical hardwood plywood constructions are displayed in Figure 1. 

In addition, the effect of ventilation rate on chamber concentration is different for each wood product type, i.e. particleboard, medium density fiberboard, hardwood plywood paneling. 

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 principal wood composite products currently in use in the United States and Canada, based on volume, are plywood (17.5 million cubic meters), oriented strandboard (16.8 million cubic meters), particleboard (10.3 milHon cubic meters), medium density fiberboard (3.4 million cubic meters), hardboard (2.0 million cubic meters), hardwood plywood (1.0 million cubic meters), and laminated veneer lumber (1.2 million cubic meters) (13). These products are described below. While all of these composites occupy an important place in the market now, some of these products are gaining in importance while others appear to be losing market share to other composite products. 

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