Spray coating

Spray coating is a technology used to coat the surface of the bottle to improve the sliding and brightness properties of the treated bottles. This is a very effective method in comparison to additives inside the bottles or preforms, as it doesn’t affect the material properties.
Often , additives have an impact on material clarity – getting a bit clowdy – or worse, on the material properties like barrier, stress cracking, etc …

Existing technologies

Bottle spray coating

Basically the origin of this process can be found in the USA, where it is commonly used. The spraying of the product is pretty brutal, with a lot of overspray who basically drops down on the in/outfeed conveyor.
As a result of this the conveyors are getting contaminated and the oil track can be followed underneath the conveyor. Depending on the product used, it dries out  when the line is not running, and prevents the conveyors from starting after a while. They have to be manually ‘helped’ to get them going again. Issues with these systems in the product dosage, as often too much product is sprayed onto the bottles, who results in label adhesion & printing problems @ the end customer.
As a result of the above, these systems have a lot of hidden maintenance costs after a while.

Preform spray coating

Similar to the bottle spray coating, there are different spraying systems on the market for spraying preforms. They are basically all based on the same system , spraying over the preform bin, as preforms are dropping into it during production.
Down side here is the uncontrolled amount of product on the preforms as well as the risk of spraying inside of the preforms. Depending on the used product, is leads often to dirt/product buildup in the mould and results in an obligation of regular mould cleaning accompanied with the necessary downtime.

Health & safety risks

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