Light-curing adhesives, or UV glues for short, are mainly used in connection technology where rapid curing is required. These one-component products cure within seconds after irradiation with UV light at room temperature. This allows for very short cycle times, important when large numbers of pieces are being manufactured.
The use of purely UV-curing adhesives requires that at least one of the components to be joined has sufficient light permeability or the adhesive surface can be exposed directly to a UV source. For components that have shadow zones and therefore cannot be exposed completely, dual-curing adhesives are suitable, which, in addition to curing with light, feature a second curing mechanism. Here, thermal, anaerobic or humidity post-crosslinking systems are available.
Different application and processing conditions
UV-curing adhesives are generally optimized for specific applications and operational conditions. Therefore, a wide range of viscosities (from low viscosity, to non-sag and gap-filling) and mechanical properties (soft, flexible to high-strength) are available. Depending on the properties of the product, the application can be carried out through dispensing or jetting.
Applications for UV and light-curing adhesives
UV and light-curing adhesives are used, for example, in the following areas:
- Loudspeaker assembly: Bonding of membranes and coils
- Electronics: Dam & fill for the encapsulation and protection of sensitive components
- Electrical engineering: Embedding of passive components
- Displays: Optical bonding, assembly of cover plates
- Automotive: Active Alignment of Camera Modules (CCM)
- Optics: Bonding of field and ancillary lenses, fiber optic couplers
- Watch industry: Bonding of watch glasses in metal and plastic housings
Advantages of adhesives
UV-curing bonding as an alternative to conventional joining techniques allows for almost any combination of materials, even difficult ones, such as plastic-metal or metal-glass connections. Since the adhesives are cured at room temperature, substrates are not exposed to thermal stress during cure.
The right product for your application
UV-curing adhesives from Polytec PT are based on epoxy, acrylate and / or hybrid systems. These cure in a very short time and show excellent adhesion to glass, metals and most plastics. The fluorescence properties of some adhesives also allow for cost-effective process control (optical inspection) of the bonded assemblies under UVA light. The UV adhesives in Polytec PT’s portfolio also vary in their curing system. Depending on the type of adhesive, crosslinking takes place either in a radical, cationic or dual-curing reaction.