Plywood trends

Some report that over 50 percent of the urea-formaldehyde resins consumed went into particleboard. This is brought out because there may be a shift away from urea resin for certain types of oriented particleboard used in structural plywood constructions. Historically, particleboard has been used for inner plies as previously mentioned in some hardwood plywood. There is now one plant in production in Idaho which produces mechanically oriented strand particleboard for use specifically as core for softwood plywood production. It is anticipated that this trend to some degree will increase in the future, and phenolic resins appear to be the mechanism with which this particleboard will be bonded. 

Reasons for the importance of recycled wood in PB manufacturing can be summarized as follows. The Japanese PB industry has used wood residues from plywood production. However, such wood residues have become insufficient for PB production because of the increasing production in the PB industry and the decreasing trend in the plywood industry. PB mills have had to use other domestic wood chip or imported wood chips. With such problems of raw material, some mills in favorable locations for collection have began to use recycled wood. 

Hot pressing. These presses are hydraulically operated and have 10-50 openings (daylights), each of which can hold one sheet of plywood. The trend is towards more daylights which means that hand loading is not fast enough. Instead the plywood is preloaded on racks and fed into the press in a single movement and simultaneously the hot-pressed panels are unloaded. 

The domestic hardwood plywood industry has been trending towards the use of water based topcoats for some paper overlay, printed, and natural hardwood paneling products to reduce volatile organic compound emissions. To achieve desired surface product properties formaldehyde is often a component of the topcoat. 

In-plant quality control and routine acceptance testing by property verification organizations such as the Hardwood Plywood Manufacturers Association and the National Particleboard Association require a method more efficient than the chamber for routinely monitoring trends in emission characteristics of products. The relationship between chamber and the small scale desiccator test observations is illustrated by a series of 76 tests accomplished during the past year on hardwood plywood wall panel products at a chamber loading rate of 0.29 sq ft per cu ft ... 

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