In addition to unloading, delivery and application equipment, many auxiliaries are available to help develop a complete integrated dispensing solution for your adhesives and sealants.
One of the most prevalent concerns when bonding materials is how to get a strong bond between mismatched substrate surfaces. Generally, when bonding like materials, there are adhesives available that will strongly bond the two surfaces at the interface of the substrates. However, in many manufacturing scenarios the need to bond different materials with very dissimilar physical and chemical properties frequently arises. For example, a reasonably rigid material such as polycarbonate (PC) may need to be bonded to a more elastic polyethylene (PE) material. Since the chemical makeup of these materials is quite different, they will tend to bond differently to various adhesives. A certain adhesive may bond well to the PC, but not well – if at all – to the PE, and vice versa.
There are methods to chemically treat the surface of one or both of the materials using primers, solvent cleaners or degreasers. While many of these chemical methods work quite well, they require the use of materials that may expose the manufacturer to dangerous or toxic matter. Such materials may also require expensive or time-consuming disposal methods. Most importantly, many toxic or dangerous materials cannot be used in the manufacture of medical devices that are implanted in the human body.
Other mechanical means, such as sanding or corona/flame treating, are also used to get a strong adhesive bond. However, of all the surface treatment methods, plasma has a proven application and manufacturing history helping bond dissimilar materials including metals and various plastics. It can reduce manufacturing time and costs by potentially eliminating the need for primers. Stronger bonds from plasma can be a combination of several plasma processes. Depending on the process gas selected, plasma can clean, activate and roughen the surface to optimize the strength and quality of the bond by enhancing the physical and chemical aspects of the bond.
Adhesives and sealants all require curing after application. As production requirements for faster turnaround, increased line speeds, greater productivity and improved efficiency have become more demanding, manufacturers are increasingly looking for the best curing solution.
Ovens and EB/IR methods can be employed to provide adequate curing of a substrate. However, ultraviolet (UV) curing systems are emerging as the most reliable, durable and cost-effective for a wide range of products. Whether the product is wood, plastic, glass or other heat-sensitive substrate, UV curing systems deliver greater application flexibility with a range of precisely focused and flood reflector geometries. They emit no ozone. Dichroic-coated temperature stable glass reflectors provide cooler operation, and no internal gasketing virtually eliminates the possibility of arcing.
Foaming systems produce homogenous foam material by mixing inert gas with typical flowable sealants. The gas expands to create a closed-cell foam as the material is manually or robotically applied to components. As a result, foaming systems typically deliver 40-50 percent gas content of mixture, providing economical material usage, faster cure time of materials and reduced gasket weight.
The system processes and dispenses a variety of high-performance materials, including silicones, urethanes and plastisols at elevated or ambient temperatures. No chemicals are used in the foaming process so foamed sealants retain their basic physical properties, such as temperature and chemical resistance. The gas content of the foamed material can be adjusted to control material durometer, compression set resistance and flexibility.