| 摘要 |
<p>A linear polyester granulate is coloured with a sol. dye in a rotary mixer, at between 120 degrees C and just below the softening temp. of the polyester, pref. at 150-170 degrees C. Mixing is pref. under reduced press. to avoid oxidn. of the polyester or dye, and is stopped as soon as the dye is fixed to the surface. Dyes which are stable after 5 mins. at 300 degrees C are used, usually in an amt. of 0.3-1 wt.%. Dry granulate is pref. first moistened, so that the dye adhers to the surface and is not drawn off when the vacuum is applied). The dye is fixed to the granulate surface and not detached in subsequent transportor storage, without use of a bonding agent. Dusting of the brittle granulate, causing problems in pneumatic transport and melt spinning is prevented. Moist granulate can be used, and simultaneously dried and coloured.</p> |
