Timothy H Reid

US Patent:

45171475, May 14, 1985

Filed:

Apr 13, 1984

Appl. No.:

6/599599

Inventors:

Michael N. Taylor - Tacoma WA
Timothy H. Reid - Tacoma WA

Assignee:

Weyerhaeuser Company - Tacoma WA

International Classification:

B29J 502

US Classification:

264 83

Abstract:

An improved hot gas pressing system for use in manufacturing wood-based composite panels reduces in-press time substantially while reducing blistering, pitting, and warping in the final panel. Condensable steam as the preferred gas is injected into both faces of the mat after the press closes to an intermediate position compressing the mat to an intermediate density. After the steam is applied for a predetermined time period at the intermediate density quickly raising the mat temperature, a steam through step is applied after which the press is closed to its final position. Steam is reapplied to both surfaces of the densified mat to maintain temperature further reducing cure time of the adhesive after which venting and vacuum steps are applied to both surfaces of the mat to reduce internal pressure and remove moisture from the mat prior to opening of the press.