Wood bonding method.
The invention is a method of gluing wood using a reactive
two-component thermosetting adhesive such as a
phenol-resorcinol-formaldehyde (PRF) condensation product. One component
is first coated on one of the members to be bonded. The second component
is then spread directly on top of the first in a manner to minimize
mixing; e.g., by spraying. When the mating member to be bonded is placed
against the adhesive-coated first member and pressure is applied, the
components are mixed. This begins the curing reaction between the
components so that a thermosetting adhesive bond is formed. With
selected adhesives, very rapid curing times are possible. A preferred
adhesive has a first component comprising a PRF resin mixed with a
methylene group donor hardener such as paraformaldehyde. The second part
is also a PRF resin. No hardener is present in the second part. Instead,
an oxygen- and nitrogen-containing heterocycle is used as an
accelerator. Morpholine is a preferred compound. Cure times as low as
two minutes to a handleable product are possible. The method is
particularly useful for the manufacture of laminated veneer lumber.
ISSUE DATE: 08/31/99. INVENTOR(S): Winterowd; Jack G., Puyallup,
WA, et al. ASSIGNEE(S): Weyerhaeuser Company. FILING DATE: 12/17/96.
NUMBER OF CLAIMS: 8. PATENT NUMBER: 5944938.