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After ten years on the market, the BöttcherPro Silux 20 and BöttcherPro Silux 35 anti set-off spray powders are firmly established in our product program. The range has now been effectively extended with the worldwide launch of BöttcherPro Silux 15 and BöttcherPro Silux 23. Spray powder is used in every sheetfed offset press, except in UV printing. The powder grains serve as spacers in the delivery pile and prevent the freshly printed sheets from sticking together. Thus it is extremely important to select a spray powder with the right grain size. The higher the paper weight, the larger the grains must be. Aside from the right grain size, relative particulate content and water-solubility are also of crucial importance.
Low particulate content
Particulate matter is defined as dust consisting of particles with grain sizes of less than 10 μm. These fine particles pose a greater health hazard for printers, as particulates are known to be respirable. This means that dust particles intrude deep into the pulmonary alveoli and attach themselves firmly. Over time, particulates can cause severe lung disorders in printers.
A higher relative content of particulate matter also leads to significantly higher powder consumption, as particulates play no role in the powder’s spacer function. The mechanically controlled air stream distributes these fine particles – in the delivery stack and unfortunately throughout the printing shop as well. Thus powders with low relative particulate matter content are preferable. Volume losses occur during the production of lowparticulate powder, as particulates are removed from the powder. This explains why prices for low-dust products are generally higher. Metered quantities can be reduced by roughly 20% in the printing shop, however (thereby offsetting the higher costs).
Water-solubility
All BöttcherPro Silux spray powders are made from different types of starch, including wheat, corn and potato starch. As we all know from using starch in cooking or baking, starch is soluble in water. However, this property would be disadvantageous in printing or in finishing processes for print products with water-based coatings. The powder particles would intrude into the wet coating layer and alter the gloss or surface structure of the coating. Our powders are treated (coated) in such a way that they do not dissolve in water but instead remain floating on the surface. This can be demonstrated by means of a simple experiment. All Böttcher spray powders are ideally suited for use in modern presses with integrated varnishing units for dispersion varnishes and can be processed optimally in all powder sprayers. The coating ensures good flowability and prevents powder clumping (caused by humidity) during storage.
