Phenolic resin-based adhesives and methods of using same in preparing laminated veneer lumber (LVL)

• Main Authors: JEAN-PASCAL THERBERGE, MILLARD E FOUCHT, BOBBY L WILLIAMSON, BARRY W SEWELL
• Format: Patent
• Language: English
• Published: 08.12.2005
• Edition: 7
• Subjects: ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; ADHESIVES; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; DYES; LAYERED PRODUCTS; LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT ORNON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NAILING OR STAPLING MACHINES IN GENERAL; NATURAL RESINS; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ORGANIC MACROMOLECULAR COMPOUNDS; PAINTS; PERFORMING OPERATIONS; POLISHES; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; USE OF MATERIALS AS ADHESIVES; WORKING OR PRESERVING WOOD OR SIMILAR MATERIAL; WORKING VENEER OR PLYWOOD

Adhesive compositions and methods of using the compositions in the production of laminated veneer lumber (LVL) are disclosed. The adhesive compositions comprise a thermosetting phenol-aldehyde resin having at least one of (A) a number average molecular weight (Mn) of at least about 450, (B) a weight average molecular weight (Mw) of at least about 2000, and (C) a Z-average molecular weight (Mz) of at least about 6000, wherein said Mn, Mw, and Mz are measured using gel permeation chromatography (GPC), a ketone-aldehyde resin cure promoter, and optionally other components (e.g., a tack-promoter or a catalyst). The adhesive compositions minimize or eliminate the art-recognized problems of glue line dryout and steam blowout, associated with LVL manufacture from both low-moisture veneers and high-moisture veneers, respectively. Furthermore, the adhesive compositions provide fast tack-build and curing as well as ultimately good bonding characteristics.