Panel flakeboard

Evaluation of Gluebond Quality. Structural flakeboard panels were prepared in the laboratory with sweetgum flakes 3 inches long, 0.015 inches thick, and variable widths. General conditions for panel preparation were ... 

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.)... 

Average physical and mechanical properties of the flakeboards are summarized in Table I. On the average, panels bonded with the lignin/phenolic resin... 

In three-layer flakeboards based on five softwood and hardwood species of 4, 10, and 18% moisture content, with press temperature of 177 °C, 6-min press time, and 3% isocyanate binder, the results showed that moisture content of wood was the most important variable at 18% moisture level, IB and bonding properties were lowest. Species of wood influenced strongly the bonding efficiency. In almost all cases the bending properties were the key characteristic of the panel performance. Southern pine produced the boards with lowest IB (81-116 psi), and red oak gave the highest IB values (98-213 psi) (J95). 

Wood and wood-based materials such as plywood, fiberboard, paper-overlayed panels, and flakeboard, have specific properties which must be taken into account when formulating finishes for them. 

The wood raw material used was red oak flakes. Red oak, an abundant species in the North Central United States, is a relatively dense hardwood, known to be rather difficult to bind. The ultimate goal was the development of a roof decking panel which required a 1-1/8 inch (29mm) board, considerably thicker than typical flakeboard products. An exterior grade binder had to be used but conventional aqueous phenolics are relatively slow curing resins. Polymeric MDI was evaluated in an attempt to achieve the necessary exterior durability without the excessively long press times otherwise needed for curing such thick boards. 

Among other hardwoods indigenous to the North Central United States are maple, birch and aspen. These species have little commercial value but are found in areas close to major markets. Mobay sponsored a study, conducted by the Institute of Wood Research at Michigan Technological University, to determine the effects of processing variables on isocyanate-bound flakeboard prepared from a mixture of these species and to compare resultant panel properties with those of a standard panel prepared with a commercial aqueous phenolic resin under typical processing conditions for that type of resin. 

Panel Characteristics - Mixed Hardwood Flakeboard Type Single layer... 

Processing Parameters For Standard Panels Mixed Hardwood Flakeboard ... 

To summarize the mixed hardwood flakeboard study, it can be said that good quality panels were made with Mondur MR at reduced press time, temperature and binder levels and increased flake moisture content vs. the commercial phenolic resin. 

Flakeboard- A manufactured wood panel made out of 1"- 2" wood chips and glue. Often used as a substitute for plywood in the exterior wall and roof sheathing. Also called OSB or wafer board. 

The copolymer resins of natural products were also evaluated for their bonding qualities in particleboards and in composite panels involving flakeboard cores with veneer faces and backs. 

In conjunction with commercial development of the copolymer resins, two such resins (one tailored for particleboard and the other for plywood) with 40% by weight of their phenol replaced by peanut hulls extracts were synthesized as previously described and submitted to an industrial laboratory for evaluation in bonding thin (1/4 thick) oak and southern pine flakeboards and in composite panels where 1/8 southern pine veneer faces and backs were laminated onto oak flakeboard cores. 

One day after the flakeboards were made, the oak flakeboards having a 120 seconds press time were used to laminate with 1/8 southern pine veneers on face and back to form the 1/2 composite panel by the plywood resin. After 20 minutes close assembly time, the panels were hot pressed at a platen temperature of 300 F for 2 or 3 minutes under 200 psi platen pressure. 

The American Plywood Association (APA) 6-cycle test was used to evaluate the properties and durability of the composite panels. The results of the tests along with other physical properties of core flakeboards are listed in Table 8. In Figure 5, the dependence of board thickness (spring back thickness) immediately after hot pressing on the press time is shown separately for each of the two wood species and resins. 

Table 8. Physical Properties and Test Results for Flakeboard Cores Subsequently used to Form Composite Panels. 

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