Why do UV(light-curing) adhesives turn white after curing?

In the glass industry, the whitening phenomenon of UV glue after curing is usually caused by the formation of tiny bubbles in the glue layer. This is because during the curing process of the glue, shrinkage occurs. If the thickness of the glue layer is uneven or the hardness is too high, the internal stress cannot be released, and tiny bubbles will form, presenting a whitening phenomenon. The solutions include choosing a flexible formula UV adhesive, controlling the uniformity of the adhesive layer, using low-power UV lamps for initial curing, and then using high-power UV equipment for deep curing.

Second, why does the glue still not dry after being applied for a long time and the surface is sticky to the touch?

After the glue has cured, due to the inhibitory effect of air, the surface of the glue cannot be de-adhered, resulting in the phenomenon of the surface being sticky to the touch. The solutions include the use of higher-intensity ultraviolet light, higher photosensitive doses, a fast-reacting photosensitive agent system, and ultraviolet light sources with a wavelength of 365nm.

Iii. Is UV glue toxic? Why does the skin become red, swollen and itchy after using UV glue?

UV glue is a green and environmentally friendly economic chemical product. It contains no organic solvents and is a 100% solid content glue. It does not have the hazards of being toxic, carcinogenic or pathogenic. However, the acrylate series oligomers and some acrylate series monomers in the glue may cause certain irritation to the skin. When first exposed, improper protection or long-term exposure to high concentrations may cause skin allergies, such as redness, swelling, rashes, and itching. It is recommended to maintain a well-ventilated environment. Operators should wear protective equipment, wash hands frequently, change clothes and gloves, and rinse immediately with clean water after skin contact.