Extr strong

A S THE applications for OSB la.expand and become more varied, from roof and wall sheathing to flooring, panel strength becomes an increasingly important consideration. And a major factor in panel strength is the binder used to hold the wood particles together.

According to manufacturers, high performance binders can help create OSB panels: o with increased physical strength. ICI's high performance Rubinate binders, for example, react with the moisture in the wood to form a strong, chemical bond between adjacent wood particles, essentially weaving the two pieces together. Conventional resins rely solely on physical bonding, similar to gluing two pieces together. o with improved fastening and edge holding. When driving fasteners around the perimeter of a traditional OSB board made with PF, the strands could break out of the panel, compromising panel integrity at the fastener points. o with natural looking glue lines but no resin spotting. providing a more homogenous looking, aesthetically pleasing panel. o that are less susceptible to swelling when exposed to water, providing a flatter panel that reportedly is less likely to warp than con- ventional OSB. Greater moisture resistance also helps reduce sanding, replacement and patching. o that possess excellent creep performance. Boards reportedly can withstand greater weight before they begin to sag and will recover once the weight is removed. o that may contain no added formaldehyde from the binders, unlike most conventional resins. o that may be lighter, while maintaining the required strength and performance characteristics.

. that are less likely to flake pop. "Less strand popping means less sanding is required," said an ICI spokesman. "Although PF formaldehyde boards may be less expensive initially, there's more sanding, which is more time consuming and more expensive in the long run."

A major factor in panel strength is the binder used to hold the wood particles together.

End users are becoming believers. Notes ICI business manager C. John Galbraith: "Demand for OSB made with Rubinate binders has increased more than l0 times since 1988."