Лако-красочные материалы — производство

Categories of uses of UV aerobic acrylic adhesives are listed in Table 7. One category is the bonding and lamination of clear materials such as glass and plastics. Because UV aerobics exhibit high strength, toughness, and good structural properties, the second category has been designated ‘‘light welding’’: a process of joining parts by bridging the joint with cured adhesive, replacing long cure times or mechanical fasteners. A third category is adhesive potting and speciality coatings on smooth surfaces such as metal.

1. Light Welding

The ability to bridge bond many surfaces while retaining structural properties has led to a new concept for the joining of abutting surfaces. ‘‘Welding with light’’ is the process of laying a bead of liquid adhesive across the joint formed by abutting metal, glass,
ceramic, thermoplastic, paper, and other surfaces and joining them by polymerizing (curing) the adhesive in a few seconds with exposure to long-wave UV light. Parts to be joined can be positioned to exacting tolerances. The adhesive may be applied either before or after positioning and then fixtured or ‘‘welded’’ on demand by exposure to UV light. The low shrinkage of UV aerobics helps assure nonmovement of parts due to the curing cycle. Small parts can be joined in 1-10 s at room temperature. Thick bondlines require longer times or more powerful light sources.

Some ferrite parts require bridge bonding because adhesive between the surfaces interferes with electrical properties. The common technique of using a paste epoxy requiring long time-cycles or heat-cures can be replaced by a fast-curing ‘‘light-welding’’ technique. The parts are held in position, and a bead of thixotropic UV aerobic adhesive is applied across the joint and cured with UV light. A 200 W in. industrial light requires 2 s, while a low-power ‘‘black light’’ effects cures in 30 s. Figure 10 illustrates various UV applications.