Poplar bark as extender for glue mix used in manufacture of plywood

Abstract From the Canadian patent

The invention relates to the manufacture of plywood. It is known to use in adhesive for plywood manufacture various extenders and a commonly used one is comminuted corn cobs. Comminuted corn cobs have recently been in short supply, which has led to attempts to find other satisfactory extenders. It has now been found that comminuted bark of aspen trees can satisfactorily be used in place of comminuted corn cobs and that there arises an unexpected advantage when using the comminuted bark. The maximum assembly time i.e. the time which, can elapse between the start of laying up of the veneers to form the plywood and the application of heat and pressure to cure the adhesive is increased.