UV and light-curing adhesives: A guide to selection and process
Light-curing adhesives only harden when they are meant to – via UV or visible light in seconds. This makes them ideal for paced manufacturing and transparent components. This guide shows how the curing process works and when it is appropriate.
To the point: When are UV adhesives worthwhile?
UV/light-curing adhesives are advantageous when fast, controlled curing and high cycle rates are required, and at least one of the bonding partners translucent . Benefits include: curing in seconds at the push of a button, long open time before exposure, and transparent adhesive joints. A suitable light source (wavelength, intensity) is required. Specifications and irradiation requirements are provided in the technical data sheet.
How the curing process works
The adhesive contains photoinitiators that initiate cross-linking at the appropriate wavelength. Only exposure to light triggers the curing process – until then, the adhesive remains liquid and repositionable. The wavelength, intensity, and exposure time specified in the data sheet are crucial.
Strengths and prerequisites
| aspect | Evaluation |
|---|---|
| Curing speed | Seconds, at the touch of a button |
| Positioning time | long (until exposure) |
| Transparent joints | very good |
| Requirement | Light must reach the adhesive joint |
| Shade areas | problematic – dual-cure possible |
Guideline values – the specific suitability depends on the product and application and must be checked in the respective technical data sheet.
Typical applications
- Glass and plastic bonding (visible parts, optics),
- Electronics and sensor manufacturing with high cycle rates,
- Fixing and potting small components,
- Medical device assembly (type-dependent, observe approvals).
Solve shadow areas
Where light cannot reach the joint, dual-cure systems, which additionally cure through moisture or heat. This ensures that even the hidden portion hardens completely.
What you should pay attention to
- Match the light source and wavelength to the adhesive
- Intensity and exposure time according to the data sheet,
- Check the light transmittance of the substrates,
- Observe occupational safety regulations (UV protection).
The right light source
Crucially, the lamp's wavelength must match the adhesive's photoinitiator and the intensity must be sufficient. LED UV lamps are now widely used. Irradiation distance, duration, and intensity determine the degree of curing – values can be found in the data sheet.
Visible and functional bonding
Light-curing adhesives produce clear, clean joints and are suitable for glass, transparent plastics, and visible connections. In sensor and electronics manufacturing, they enable short cycle times with precise positioning.
Frequently Asked Questions
What happens in shadow zones?
Pure UV adhesive does not cure there. Dual-cure systems also cure through moisture or heat.
Is UV radiation an occupational safety issue?
Yes. Use appropriate eye and skin protection and operate the lamp according to the manufacturer's instructions.
How long is the positioning time?
The position is practically arbitrary until exposure – the adhesive remains liquid and correctable until the light starts the curing process.
Sources and technical basis
The information is based on manufacturer data sheets and recognized principles of adhesive bonding technology. Irradiation parameters, suitability, and resistance are product-dependent and can be found in the respective technical data sheet.
How SILITECH supports
Tell us the substrate, cycle time and geometry – we will recommend the appropriate light-curing adhesive including light source and provide the data sheets.
