| 摘要 |
<p>Vinyl chloride (co)polymers are prepd. in powder form for plastisols having improved rheological properties by concentrating a latex of the polymer having a solids content of 30-60% and contg. three gps. of particles, by removing in the liq. state, a fraction of the aq. phase followed by eliminating the residual water by drying. The novel features are that (1) the solids content of the latex after concn. is 50-80 wt.%, (2) the absolute difference between the solids contents before and after concn. is greater than 10%, pref. 12-25%, and (3) the three gps. of particles have av. diameters of 1.2-2.5, 0.12-1 and 0.01-0.4 microns resp., pref. 1.5-1.8, 0.21.0.45 and 0.03-0.12 microns, the dia. ratios of big to medium and medium to fine particles, same or different, being 2.5-10, pref. 4-7, and the wt. ratio of big to medium and medium to fine particles being 1-9, pref. 1.5-6, at least 90 wt.% of the particles of each gp. having a dia. of 0.7-1.6 times the av. dia. of the gp. The plastisols obtd. with the powder have better rheological props. than those obtd. when the latex has been directly to obtain the powder. The polymer powder also has a low emulsifier content which does not affect its other props. The polymer is suitable for sheets, films, yarns, containers, cellular prods. mouldings, and coatings.</p> |
