| 摘要 |
<p>A method of producing an aq. polymer dispersion in the presence of monomers, emulsifiers and radical formers uses re-adjustment of the dose of emulsifier soln, possibly also monomer and aq. initiator soln. During polymerisation the reaction mixt. (latex) is periodically sampled and fed, at constant temp. in a water vapour-satd. protective gas atmos., over a droplet-forming surface; after a predetermined number (N) of droplets has dripped from this surface, the material is collected and automatically weighed and from this reading the quantity of emulsifier and/or monomer or initiator soln. is readjusted. Pref. the weight (G) is compared with a set-point value and the quantity of soln. which is added is sufficient to keep the difference between actual and set-point values as small as possible. The pref. set-point is the value of (G) for the final dispersion. The pref. protective gas is nitrogen or a noble gas, opt. contg. vapours of those components which are present in liq. form in the polymer dispersion. The relationships between latex particle dia., emulsifier content, surface tension and degree of saturation are used for controlling the prod. Particle sizes in the range 30-1000 nm (pref. 80-600) are made.</p> |
