| 摘要 |
<p>The present specification discloses the production of low density self-sustaining foams of cured urea/formaldehyde resin material. Such foams can be used, for example, in the building industry for thermal insulation purposes. The invention disclosed is a method of producing a cured urea/formaldehyde resin foam having a shrinkage on drying of less than 20% by volume, the method including the step of forming a homogeneous wet foam from an aqueous resin solution and an aqueous solution of a hardener for the resin, so that the freshly made wet foam has a total reactive resin solids content of at least 35% by weight. In another aspect the invention disclosed is an apparatus for carrying out such a method, the apparatus including a foaming column having an upstream region constituted by inert particulate material and a downstream region constituted by an inert reticulated structure.</p> |
