Slot Die Coating Technology

Slot die coating technology is a function of the coating process, auxiliary system and fundamental technique. The decision to utilize a coating technology needs to be analyzed against these functions to determine best fit. In the era of clean, thin and precise converting operations, a customized coating system is necessary to have a technical edge. Building the system from the material up to the process sets the stage for a high precision tool designed around the process needs. The dramatic increase in the expectations of coated products, in areas as diverse as optical films to battery technology, has put substantial pressure on the systems used to produce the next generation of coated products. It is time for the equipment suppliers to step up as new tools and techniques are required. With increased speeds, thinner coatings and increased functional performance, awareness of coating techniques and technologies is required. The world is changing and new tools are needed to compete in the changing world markets. An awareness of coating techniques, technologies and systems allow for novel adaptations and application to new market opportunities. Slot die technology provides innovative tools that will help coating companies improve precision, tackle new markets, and develop new processes. Introduction Slot die coating was developed as the need for a better and more efficient coating method was required. This process has been successful in replacing other coating methods in applying many types of solutions. A slot coating die is a device that is capable of holding a fluid’s temperature, distributing a fluid uniformly and defining a coating width. The die is comprised of steel body sections that house the fluid flow chamber. Slot die coating has four main advantages: 1. Increased production speeds. In slot die coating a positive displacement pump is utilized to deliver a constant supply of coating fluid to the slot die. Modification of the coating fluid formula, such as an increase in the concentrate of solids, is allowable in a slot die. This decreases the workload of the drying units, leading to increased production rates. 2. Positive coatweight control. The fluid delivery system delivers a constant supply of coating fluid and variations in coatweight are controlled by regulating the pumping rate to line speed ratio. 3. Cross-web distribution control. The slot coating die’s manifold geometry is designed to uniformly distribute the coating fluid, based on the fluid’s rheology. In the case of an adjustable lip die, the lip adjustment system is used to fine tune the cross-web distribution as the fluid exits the slot die. In a fixed