Fiberboard

Fiberboard (American spelling) or fibreboard (Commonwealth spelling) is a type of engineered wood product that is made out of wood fibers. Types of fiberboard (in order of increasing density) include particle board, medium-density fiberboard (MDF), and hardboard.

Fiberboard is sometimes used as a synonym for particle board, but particle board usually refers to low-density fiberboard. Plywood is not a type of fiberboard, as it is made of thin sheets of wood, not wood fibers or particles. Fiberboard, particularly medium-density fiberboard, is heavily used in the furniture industry. For pieces that will be visible, a veneer of wood is often glued onto fiberboard to give it the appearance of conventional wood.

In the packaging industry, the term "fiberboard" is often used to describe a tough kraft-based paperboard or corrugated fiberboard for boxes.

"Fiberboard" is also an intermediate product, an output of a pulp mill used as input for a paper mill.

Urea-formaldehyde (UF) resins are dominantly used in the medium density fiberboard (MDF) industry because of their low cost and fast curing characteristics. However, pressures on the use of UF resins are mounting steadily due to potential problems associated with formaldehyde emission. On the other hand, phenol-formaldehyde (PF) resins are more durable and do not emit formaldehyde after cure. The industry has traditionally shied away from using PF resins due primarily to their higher cost and much slower curing rate than UF resins. However, the press times for PF-bonded fiberboard can be substantially reduced by manipulating the fiber mat temperatures, molecular weight distribution of PF resins and pressing parameters. As a result, the press times for PF-bonded fiberboard can be made comparable to those for UF-bonded fiberboard. Also, the resin content required for PF-bonded fiberboard is less than 5% to achieve a good board quickly. This is considerably lower than that required for UF-bonded fiberboard.

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