| 摘要 |
Aqueous dispersions of polyethylene having at least 35% of solids are produced by polymerizing ethylene in an aqueous alkaline medium at 110-150 DEG C. and a pressure of at least 400 atm. in the presence of 5-12% of a potassium salt of an at least C10 saturated fatty acid as emulsifier and 0.001-0.5% of a water-soluble persulphate as catalyst. The emulsifier may be prepared in situ from lauric, stearic, myristic or capric acid and an excess of potassium hydroxide. The persulphate may be the ammonium, potassium or sodium salt. The polymerization may be carried out at a pH of 8-12.5 which may be adjusted with tertiary potassium, or sodium, phosphate. The polyethylene may be precipitated from the dispersion with a mixture aq. hydrochloric acid and methanol. The polymerization may be continuous.
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