Extrusion Dies Industries, LLC (EDI) and ITW Dynatec have reached a worldwide agreement to market turnkey hot melt adhesive coating stations combining ITW Dynatec's melting and fluid delivery equipment with EDI's slot die systems, the companies announced today.
The agreement makes available to operators of coating and laminating processes a single, fully integrated system whose performance is guaranteed by the partner companies. The system can be designed to apply virtually any hot melt material over the full range of viscosities and at temperatures from ambient to 500 deg. F. (260 deg. C.). Depending on equipment parameters and the type of application, the system can coat at speeds exceeding 2,000 feet (610 m) per minute on wide widths, and in coat weights down to 0.5 mil (0.013 mm) or less. Coat weight accuracy can be maintained within +/-1%.
“The turnkey hot melt coating station is more accurate than other slot die or roll coating systems, making possible raw material savings that are especially valuable in these challenging times,” said Mike Budai, ITW Dynatec’s laminating and coating manager. “Key factors in this accuracy include the PLC control which regulates the entire coating station, the sophistication of ITW Dynatec’s melting and delivery technologies, and the precision and consistency of EDI’s slot die system.”
The EDI portion of the coating station is a self-contained unit, called the Modular Coating System (MCS), that incorporates mechanisms for fine adjustment and repeatability and includes an innovation for coping with the gels, or solid particles, that occur in hot melts, noted Dennis Paradise, EDI’s vice president of sales and marketing. “EDI has a die with a motorized rotating rod in the lip area that causes gels to pass through the narrow die lip opening rather than lodging there and generating streaks,” Paradise said. “This makes it possible to achieve coat weights well below the conventional lower limit for hot melts of 1.0 mil (0.025 mm).”
Station Includes All Components for Melting, Delivering, and Applying Hot Melts
The joint turnkey coating station program builds on the versatility of the partners. ITW Dynatec is a longtime leading supplier of adhesive application systems and supplies equipment to every industry that employs hot melt adhesives. EDI’s engineering expertise enables the company to custom manufacture each slot die coating system in accordance with application requirements.
A basic component provided by ITW Dynatec is the Dynamelt™ M-Series adhesive supply unit, or melter, which is a self-contained system for melting the adhesive and pumping it to the applicator. The system includes a PLC controller with user-friendly HIM interface. Various melt rates, hopper capacities, and pump rates are available. The Dynamelt features a patented Melt-On-Demand™ Hopper which melts only the adhesive required and virtually eliminates adhesive char. Another adhesive delivery method used with this turnkey system is Dynatec's DM55 DynaDrum™ Bulk Adhesive Melter. The DM55 Drum Unloader features inflatable seals which accommodate various drum diameters, and removable platen faces allowing for field retrofit.
ITW Dynatec’s Gemini™ Automatic Hot Melt Hose delivers the adhesive from the melter to the applicator. The patented Gemini™ Automatic hose has dual heater and temperature sensors that keep the coating line up and running in the event of a hose failure. If a hose fault occurs, Gemini switches to its back-up circuitry and an illuminated control box flashes, alerting the operator to change the hose during scheduled line-down time.
The applicator, EDI’s Modular Coating System (MCS), includes the die or coating head with adjustable lip opening and a robust, adjustable support for positioning the die lip with respect to the web; idler rolls; and a precision backing roll. These components are unitized within a steel frame whose crossbars maintain straightness during operation and adjustment.
“The die support or positioner plays a critical role in controlling the number one variable in slot die application of hot melts—the angle of attack of the die with respect to the backing roll,” said Paradise. “A series of coarse and fine adjustments makes it possible to establish a precise and repeatable slot die setup.”
Turnkey Coating Stations for a Wide Range of Applications and Industries
Slot dies must be custom-engineered to fit the application. “The manifold, or internal flow channel, of every die must be designed and precision machined to accommodate anticipated throughput and the unique rheology, or flow characteristics, of the adhesive,” Paradise said. “The resulting control of flow behavior is one of the great advantages of slot die coating over conventional systems like spray or roll coating. Another is that slot dies are closed systems that maintain the hot melt fluid at a consistent temperature and distribute it uniformly across a precisely defined width.”
Hot melt adhesives are thermoplastics, normally applied at an elevated temperature, which solidify as they cool. EDI and ITW Dynatec recommend their turnkey system for use across the range of hot melts, including pressure sensitive adhesives (PSAs), amorphous polyalphaolefins (APAOs), ethylene-vinyl acetates (EVAs), polyamides, polyurethanes, UV-curable acrylates, and various elastomers. Anticipated end-use industries include medical and healthcare products, nonwovens, packaging, tapes and labels, web converting, and woven textiles.