BARK EXTENDED PHENOLIC RESIN ADHESIVE COMPOSITION AND PROCESS FOR PREPARING SAME

摘要

BARK EXTENDED PHENOLIC RESIN ADHESIVE COMPOSITIONAND PROCESS FOR PREPARING SAMEAbstract of the DisclosureA new and improved, high quality, bark-extended phenolicresin adhesive composition for bonding wood plies, particularlysouthern mill wood such as the southern pine, comprising thereaction product of finely ground wood bark particles treated witha caustic solution and a low molecular weight, aqueous alkalinephenol-aldehyde resin. The resin has a low degree of polymeriza-tion and is soluble in all proportions in ethanol. The resultingadhesive has a proportion by weight of total resin solids in therange of approximately 25.1% to 20.9% and a proportion of totalsolids in a range of approximately 40% to 40.85% based upon thetotal weight of the adhesive composition. The adhesive has aviscosity in a range of approximately 9,000 centipoise to 10,600centipoise. An adhesive of this type particularly suitable forbonding western wood species such as the Douglas fir comprisesthe reaction product of finely ground wood bark particles treatedwith a caustic solution, a low molecular weight aqueous alkalinephenol-aldehyde resin having a low degree of polymerization,which resin is soluble in all proportions in ehtanol, and variousfillers such as wheat flour, Norprofil (Norprofil is a trade namefor powdered or ground corn and rice husks or corn cobs), etc.The proportion of total resin solids is in the range ofapproximately 24.6% to 21.9%, and the proportion of total solidsis in the range of approximately 40.28% and 38.6%. The viscosityof the resulting adhesive is in the range of approximately 2,100centipoise to 1,975 centipoise. The processes for preparing thesubject adhesives include preparing a premix comprising bark, acaustic solution, and water, then adding and mixing the remainingcomponents under varying time conditions. There is no requirementfor the external addition of heat.- 2 -