| abstract |
A curable, alkaline, melamine modified phenol-formaldehyde resin is prepared from an initial phenol-formaldehyde resole resin containing from 0.5 to 2.5 percent of free formaldehyde by scavenging formaldehyde with 1 to 12 parts of melamine for each 100 parts of the initial resin wherein the molar ratio of formaldehyde to melamine is 0.2 to 1.5 moles of formaldehyde for each mole of melamine to reduce the free formaldehyde to less than 70% of that in the initial resin and prepare a storage stable resin which contains less than 0.7% of free formaldehyde and which maintains its stability under application conditions. An ammonium salt of strong acid and additional water is incorporated in the melamine modified resin to prepare an alkaline binder. The binder is sprayed on to fiberglass with low formaldehyde emissions, good stability and rapid cure in the acid range. |