Coating matting agent should have the following characteristics
1, easy to disperse
2, good matting effect, low addition amount can produce strong matting performance
3, small interference with the transparency of the coating film
4, small impact on the mechanical and chemical properties of the coating film
5, good suspension in the liquid coating, can be stored for a long time, will not produce hard precipitation
6, Low influence on the rheology of the coating,
7, high chemical inertness
Add incompatible substances with resin to the components, they can still flow freely at high temperature baking stage but in a non-homogeneous state, after cooling will precipitate from the system arranged in the surface non-homogeneous distribution, the formation of a rough surface scattered light and thus reduce light. Such as polyvinyl acetate derivatives, cellulose esters, etc. In this system, if you do not add leveling agent and choose the appropriate incompatible substances, due to a sharp reduction in viscosity during the cooling process, when precipitated from the system can also produce a wrinkled surface.
Adding appropriate catalysts to wax matting agents will strengthen the matting effect, which is due to the curing process to strengthen the surface of the accelerator shrinkage, resulting in a fine uneven wave structure leading to further reduction in system gloss, which is composed of modified polyethylene wax and composite catalysts, can be used in TGIC or mixed systems, properly adjusted formulations can produce It is composed of modified polyethylene wax and compound catalyst, and can be used in TGIC or mixed system.
However, the addition of incompatible substances for matting has its limitations, firstly, it is difficult to prepare powder with less than 30% gloss, and excessive addition of wax-based compounds is also easy to cause its exudation from the surface to bring processing problems; secondly, the uneven distribution of components is often affected by extrusion conditions, which leads to fluctuations in gloss. Based on this, a low wax content outdoor matting agent with certain reactivity, which can prepare black system and get less than 15% glossy coating film due to the wax content, and is a relatively successful improvement of wax matting agent.
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