| 摘要 |
<p>The invention relates to a process for the production of a concentrate of from 20 to 50% by weight of titanium dioxide in polycaprolactam, wherein a 5 - 15% strength by weight aqueous suspension of titanium dioxide is metered into a solution of caprolactam in water at from 110 to 150.degree.C at the same rate at which water is distilled off, and after all the water has been distilled off the resulting mixture is polymerized at from 240 to 280.degree.C. This process allows to obtain concentrates of titanium dioxide, which have a long shelf life and a constant concentration, can readily be dispersed in the caprolactam or polycaprolactam melt, and in addition, owing to the omission of water, do not adversely affect the capacity of the polymerization plant.</p> |
