| 摘要 |
<p>Cheap and easily produced particles to improve the impact strength of hard and brittle polymers without affecting their other desirable physical properties are obtained by emulsion-polymerisation of vinyl chloride (or styrene or other vinyl compds.) to form the nucleus of the particle, with a size of 0.3 mu (or slightly larger, vitrification temp. >25 degrees C), forming a layer of a rubber-like emulsion polymer (pref. polybutylacrylate with a little methacrylic acid, vitrification temp. 25 degrees C) to a size of about 1 mu and finally forming a layer of a suspension polymer (pref. PVC) onto the rubber (it may be intimately mixed with the rubber). The particles formed are dried and form a free-flowing powder, which is mixed into the hard polymer (usually PVC) by usual methods prior to working.</p> |
