Reheis Chemical Company, Inc.

Jerome E Schwartz

James F Kozischek

Rudolph Ferentchak

Spray dried thermosetting resin powders in an intermediate polymeric stage are produced in the form of hollow, thick-walled, macrospherical particles having a bulk density greater than about 35 lbs/ft.sup.3 and having particle diameters predominantly in the range of about 10 to 74 microns, preferably averaging about 30 microns in diameter with greater than 90% of the particles being in the 10 to 74 micron range. The powder is produced by centrifugal atomization of a concentrated resin solution through a porous sintered metal filter in a spray drying chamber, preferably without diluting or preheating the solution and without heating the resinous material above about 160.degree. F. during spray drying. The particles are advantageously used in the dry process molding of consolidated wood fiber structures, such as waferboard and chipboard, in which wood fiber elements mixed with the resin powder are consolidated under heat and pressure sufficient to cause the powder to melt, flow and cure.

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Bloomfield, NJ, United States of America

Jerome E Schwartz