| 摘要 |
<p>A liquid phenol-formaldehyde-resorcinol resin is made by reacting principally monomeric methylolphenols, free formaldehyde and resorcinol in an aqueous solution. The ratios of formaldehyde combined with phenol in the methylolphenols, the free formaldehyde and resorcinol are critical within given ranges. A base resin product is obtained which may be further modified in various ways to form adhesive resins. One modification involves further advancement of the base resin to increase molecular weight. When this adhesive resin is combined with an appropriate hardener, such as an aldehyde, the resulting adhesives exhibit a range of versatility previously unknown in any one product. These adhesives may be used for finger jointing wood members or for room temperature cure or preheat laminating of wood. By simply varying pH of one adhesive resin within narrow limits, a range of cure times from about a minute to well over an hour can be achieved. The resins of this invention are further characterized by excellent water washability so that organic solvents or strong alkaline solutions are not required for cleanup of equipment.</p> |
