Industry Insights
New Coating Methods July 18, 2014 | by Rick Daniels, General Manager, Carestream Tollcoating and Jason Payne, Ph.D., Director, WW MFAPS Media Manufacturing

As a premier contract manufacturer for roll-to-roll coating on flexible substrates, Carestream Contract Manufacturing continuously develops new and modifies existing coating methods to meet customers’ diverse product demands.

Carestream is currently using several coating methods including reverse roll, slot die, forward roll, gravure, and various other types of hopper and slide coating. There are two ways Carestream adds new methods to its capabilities portfolio: designing them from the ground up, and working side-by-side with customers developing new coating techniques for unique purposes.

In many instances, customers require the use of fluids with specific rheologies or that contain unique components such as particulates in suspension. These often require lip or coating head cavity modifications to create products that meet the market requirements with respect to coating uniformity or down web variability.  Additionally, certain applications may require coating head cavities that reduce the propensity for settling.

In recent years layer-by-layer coating and self-assembly coatings have been developed in academe and transferred to industrial scale. Layer-by-layer examples include using chemicals which have functional groups that are oppositely charged and therefore become monolayers of self-limiting thickness. Others rely on chemical principles such as used in surfactant chemistry, where two ends of a molecule attract to different substances and create order. These are examples of future add-ons that could be used at Carestream.

Still other examples focus on patterning of flexible webs. Coating equipment at Carestream can be modified to create patches, stripes, or simply create a known density variation in the final product.

Carestream has the advantage of owning and operating coating machines with built-in flexibility to accommodate new requirements and methodologies. Their coaters include multiple coating stations on carts and re-toolable machines. This tractability allows for the added benefits of precision solution delivery, precision conveyance, drying and laminating and other methods of coating in the same pass, without new investment. Carestream can therefore put a new method on the same line quickly and inexpensively.

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