| 摘要 |
<p>In processing roofing paper with undyed granular matter strewn on its surface, an oily fluid is used to prevent dust from dispersing while they are being applied. The granules are mixed with the oily fluid at 0.1-1% of the granular matter. At least 40% of the applied oily fluid has a boiling threshold of 150-300 degrees C and a max. of 60% has a boiling threshold over 300 degrees C. In the prepn. of the roofing paper, the oily fluid is evaporated sufficiently so that the granules will absorb the fluid but retain their colour, while sufficient remains in the fluid to control dust movement during application to the paper. The process allows the use of the undyed granules which still retain their normal colour after applications to the roofing paper. Pref. a mineral oil is used for the oily fluid with a sufficient viscosity to allow the fluid and the granules to be mixed while cold. The oily fluid comes within the 'C' class danger category for transport.</p> |
