Born2Bond light-curing adhesives, especially Born2Bond™ Light Lock HV, are the most popular products in assembly processes. The speed of cure and the adhesive strength they offer are just some of the reasons why they are so popular with manufacturers. In order for the application of the product to be best suited, it is important to consider the dosage variables: product substrate, light source, light exposure and other minor factors that will affect the ability to form effective adhesive bonds.
We have 10 tips to help you achieve your planned production goals and minimise the risk of error:
- Remember to wear appropriate clothing that complies with health and safety regulations: In the case of UV adhesives, they happen to use light from the UV spectrum for curing. To ensure protection from this type of light, gloves should be worn when working, while UV light using protective eyewear with UV-sensitive protection is essential.
- Compatibility of the adhesive with the type of application: not all bonding components are compatible with UV adhesives such as Born2Bond™ Light Lock HV. Some opaque or coloured substrates do not transmit UV light, and a significant proportion of coloured surfaces contain additives (e.g. UV inhibitors) that may hinder or prevent the adhesive from curing. Using MD Polonia’s experts, we can help you select the right adhesive to meet your specific needs.
- Compatibility between dispensing equipment and UV adhesives: it is crucial to invest in the right equipment with precisely selected dispensing nozzles that will be compatible with UV adhesives. The equipment must not be transparent, it must be radiation resistant to avoid premature curing of the product. In the case of a dual curing system, attention must be paid to the correct size of the nozzle opening. If the nozzle opening is too small, there is a risk of premature curing of the product, resulting in production downtime.
- Suitable production environment: exposure to light is important. Special attention should be paid to whether the product is exposed to light. The slightest amount of light from windows or lamps can adversely affect the UV adhesive and a batch will be wasted, contributing to production delays. The UV glue container should be opaque, resistant to UV light, thoroughly sealed and not exposed to direct light (from windows or lamps). It is also important that sunlight or light from artificial lighting reaches the dispensing nozzle.
- Substrate preparation: ensure that the substrate is clean and free from any dirt. Any residue on the surface will interfere with the adhesive’s ability to wet the surface properly. It may be that some substrates will require prior preparation for bonding through, for example, polyethylene. This is related to the height of the surface energy. We will be happy to help you select the right adhesive for your particular substrate.
- Reduce exposure to shadow during curing: this will help to achieve the best results when curing the adhesive. It is important that the adhesive is fully and evenly exposed to light during the curing process itself. If the adhesive will be unevenly exposed to light, consider using a dual-cure adhesive. UV adhesives can be cured with light and then cured with moisture or other activation methods.
- Beware of air bubbles: air bubbles can directly affect the bond strength of Born2Bond™ Light Lock HV adhesive by reducing the weight of the applied product. The lines should be flushed after each time the adhesive container is filled, to reduce the likelihood of air bubbles during product application. It is also important to ensure that the pressure is appropriately matched to the viscosity of the adhesive. For low viscosity adhesives, pour-in and drop-in containers will work best, while for higher viscosity adhesives, dispensing pumps are recommended. Born2Bond™ Light Lock HV is a versatile product, as we can find it in different viscosity ranges.
- Adapting the wavelength of light to the adhesive: adhesives have a specific wavelength for fast and strong curing. Wavelengths can range from 365 nm to 450 nm, while the adhesive will cure at other wavelengths. The best results will be achieved by matching the wavelength of the UV or LED light to the wavelength of the photoinitiators in the adhesive.
- Appropriate light intensity: the intensity of the light source can also affect the curing speed of the adhesive. Higher intensities can help reduce curing time. It is important to remember that each sticker has a maximum intensity. Once the maximum limit is reached, the curing process does not accelerate or accelerates the curing too much, reducing the residual adhesion
- Ensure constant light exposure for even curing: with a moving light source, curing can be inconsistent from one application to the next. This problem can be solved by incorporating light into the automation process. This will allow parts to be substituted at a constant distance from the light and under the same light intensity.
Mascherpa offers precision, high-performance, light-curing adhesives suitable for a wide range of assembly applications. An example product is Born2Bond™ Light Lock HV, a low efflorescence and odourless instant adhesive specifically designed to bond most substrates, including plastics and rubber. The formulation is designed to have high bond strength, even in areas subject to bending, and in addition, the careful selection of formulation ingredients ensures that the product does not stain areas close to the bond line.