| 摘要 |
<p>The present invention concerns a foam having a bulk density of less than 250 g/l; the foam having a stability in air of at least 15 seconds (and preferably at least 30 seconds), the stability being defined as the time for the foam to collapse to half its volume when measured in a 111 mm internal diameter and 62 mm internal height glass beaker; wherein the foam has a stability on water at 20 °C of less than 2 hours, the stability on water being defined as the time taken for a 150 ml foam mass on the surface of 450 ml distilled water in a 111 mm internal diameter and 62 mm internal height glass beaker, to collapse to reveal a 2 cm diameter area of the water surface which is substantially free from foam.</p> |
