| 摘要 |
<p>Soiling of plastic sacks is prevented by coating with 0.2-3 (0.5-1.5) g/m2 powder consisting mainly of a finely-divided alkali(ne earth) carbonate or oxide, and having grain-size 0 1 mm and bulk density 0.1-1. Process is used for all plastic sacks which take up electrostatic charges, esp. polyethylene and PVC sacks, bags and other containers. The sacks remain clean after filling, e.g. with fertilisers, and transport, loading and storage; powder ingredients are cheap and easily available. Pref. anti-static compsn. contains CaCO3, esp. having calcite structure, and 25% sec. constits., such as (hydr)oxides or carbonates of elements of main- and side-gps. II, III or IV of periodic system, and of (hydr)oxides or carbonates of Cr, Mn and Fe.</p> |
