| abstract |
The present invention is directed to a catalyst curing system and a method of using it to reduce emissions or "fumes" of formaldehyde in resorcinol-formaldehyde or phenol-resorcinol-formaldehyde resins. Another object is to provide methods for curing or setting resorcinol and phenol-resorcinol resin systems in which too rapid gelling and setting, and also high cost, is avoided. The present invention replaces an oxazolidine moiety, normally used for the cross-linking of a phenol-resorcinol resin, with a class of compounds commonly referred to as methylolureas, which are reaction products of formaldehyde and urea chemicals. The preferred method of using an adhesive of matter comprising dimethylolurea in combination with a resorcinolic resin (resorcinol formaldehyde or phenol-resorcinol formaldehyde), in addition to comprising oxazolidine. May also include flow modifying fillers. Typical fillers used in hardeners include clays, walnut shell flours, and fine mesh sieved sawdust. |