| 摘要 |
<p>A mixt. of hydrocarbons, partic. suitable for cleaning, comprises (a) 70-85 pts.(wt.) 37-47C satd., opt. branched aliphatic hydrocarbon(s) and (b) 10-20 pts. 75-95C unsatd., opt. branched aliphatic hydrocarbon(s) having a bromine index of 5-6.5. Also claimed is a self-lubricating cleaning compsn. comprising the above mixt. and in which (a) has a kinematic viscosity of at most 100, pref. 10-100, esp. 25-50 cSt at 100 deg.C and (b) has a kinematic viscosity of at most 1000, pref. 500-900 cSt at 100 deg.C. The compsn. is used for cleaning screws in presses, partic. extruders or injection moulding machines for processing plastics. The compsn. is circulated in the screw chamber at 200-350 deg.C for at least 10 mins, causing dissolution of the plastics (e.g. PVC, ABS, polyoxyphenylene). The compsn. does not alter the surface of metals and facilitates e.g. change of materials, colours, and eliminates deposits and burnt materials.</p> |
