| 摘要 |
A thermoreactive powder is applied to the uncoated surface of the substrate (1,5) as base coat. This is heated continuously in the near infrared. It is raised to cross-linking temperature, and hardened. Alternatively it is heated to the gelling temperature, and only in a later process stage is cross-linking and hardening completed. Preferred features: On the hardened or pre-gelled base layer (2) a second layer of thermoreactive power is applied. The entire coating is then cross-linked and hardened. After hardening or gelling, the base layer (2) is cooled. Powder layer (6) and/or the second layer are irradiated for no more than 8-12 s, for gelling or hardening. Surface temperature of the thermoreactive powder is measured pyrometrically and the radiation flux density is controlled. A high power halogen lamp (7) produces the radiation at over 2500 K. Uncoated substrate surfaces are pretreated to improve adhesion of thermoreactive powder, especially by application of an electrically-conducting fluid. To power-coat a moisture containing- or absorbing substrate (1) The substrate is dried and/or moistened, leaving a defined moisture content in place, before base layer application. Irradiation at the same or increased power is used for drying. The substrate is heated above the powder melting point, fusing some of it on, immediately on application. Use of the lamp as described is also claimed; Its reflector (8) directs radiation onto the substrate. The lamp is operated such that the maximum flux density lies in the near infrared.
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