Oriented waferboard

Wood FIa.ke Boards. This category covers a range of products depending on the size and orientation of the wood flakes used. The earliest product was made in the 1950s using low density wood species, such as aspen and pine, with the flakes bonded together with phenoHc resins. Today there are two types of flake board, waferboard and oriented strand board (OSB). 

In 1932, the first plywood hot press was installed in the United States. This marked the advent of the large market for phenolic wood adhesives [51]. By 1962, the volume of phenolic wood adhesives had reached about 33 kt (solids) in the U.S. Growth was accelerated in 1962 with the development of Southern pine plywood. By 1979, the consumption of phenolic plywood adhesives exceeded 220 kt or about 25% of phenolic resin production [51]. Phenolic adhesive demand for wood products took another jump in 1964 with the commencement of waferboard production. The first oriented strandboard (OSB) plants were built in 1981 [52]. OSB soon replaced most of the waferboard production and began a period of... 

Oriented strand board (OSB) is obtained from wood chips. The orientation is designed to simulate the characteristics of a wood panel, with limited swelling and higher resistance in the fibre direction. Chips are orientated by air with a blowing machine. These panels are commonly used on building sites, and they often make part of the walls in houses, especially in the United States. If no orientation is given, the panel is called waferboard. 

Sprayable exterior adhesives of competitive performance for structural panels such as flakeboards, waferboards, and strandboards based on renewable resources. (A blood-lignin adhesive for oriented strandboard or waferboard would be an example.)... 

A 1998 survey of manufacturing costs in the Canadian industry provides comparative figures for these panels. Table 12.2 shows the price advantage that has driven the use of OSB as a replacement for plywood, once satisfactory performance had been demonstrated. Waferboard was developed in 1962, but OSB had to await the optimization of flake geometry and the development of methods allowing the flakes to be oriented. Only then, in 1981, was OSB able to demonstrate a level of performance that allowed its use as an alternative to plywood. 

Phenol formaldehyde, on the the other hand, is used to make the waterproof adhesives that are used in structural wood panel products such as softwood plywood, oriented strand board, waferboard and exterior (phenolic) particleboard. These products are commonly used for roof, floor and wall sheathings, exterior sidings, concrete forms and in pallets and numerous other products. 

SPP = southern pine plywood DFP = Douglas-fir plywood OSB = oriented strand board WB waferboard PB = particleboard. 

Foam Core Panels - A type of structural, insulated product with foam insulation contained between two facings of drywall, or structural wood composition boards such as plywood, waferboard, and oriented strand board. 

Although resol types are also used in the manufacture of wood chipboard, other forms of particle board, such as waferboard and oriented strand board (OSB) are usually made using novolac types. These resins are produced by reacting excess phenol with formaldehyde in the presence of an acid catalyst. The resin is converted to a fine powder, which is usually sprayed on to the large wafers along with molten wax, which helps the dry resin powder adhere to the wafers until it is cured under elevated temperatures of up to 200 °C. With this method, very small quantities of adhesive - as low as 2.5 g solid resin per 100 g dry wafers - can be used, while still achieving satisfactory bonding. 

In another relatively new type of particleboard, the manufacturers align long strands of wood at the surface for increased strength in the direction of panel length. This oriented-strand board (OSB) and waferboard replaced a great deal of plywood sheathing in the early 1980s. 

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