Photosensitive resin, commonly known as UV curable shadowless adhesive, or UV resin (adhesive), is mainly composed of oligomer, photoinitiator and diluent. In recent years, photosensitive resin has been used in the emerging industry of 3D printing, which is favored and valued by the industry because of its excellent characteristics. The question is, is photosensitive resin toxic?
Forming principle of photosensitive resin: when ultraviolet light (light with a certain wavelength) irradiates on the photosensitive resin, the photosensitive resin will produce curing reaction and change from liquid to solid. It can control the path of light (SLA Technology) or directly control the shape of light (DLP) technology for curing. In this way, the curing layer becomes a model.
Photosensitive resins are mostly used to print fine models and complex design models with high requirements for model accuracy and surface quality, such as hand boards, handmade, jewelry or precision assembly parts. However, it is not suitable for printing large models. If large models need to be printed, they need to be disassembled for printing. However, it should be reminded that both translucent and fully transparent printing need to be polished in the later stage. Where the polishing cannot reach, the transparency will be slightly worse.
Photosensitive resin material can not simply say whether it is toxic or non-toxic. Toxicity must be discussed in combination with dose. Generally, there is no problem after normal light curing. Light curing resin is the matrix resin of light curing coating. It is compounded with photoinitiator, active diluent and various additives to form light curing coating.
Functional UV monomer is a kind of acrylate monomer suitable for UV curing reaction. HDDA has low viscosity, strong dilution power, swelling effect on plastic substrate, and can effectively improve and promote the adhesion to plastic substrate. It has good chemical resistance, water resistance and heat resistance, excellent weather resistance, medium reaction speed and good flexibility. UV monomers are widely used in UV coatings, UV inks, UV adhesives and other fields.
UV monomer is typically characterized by low viscosity and strong dilution ability; Excellent adhesion to plastic substrate; Good chemical resistance, water resistance and heat resistance; Excellent weather resistance; Good flexibility; Moderate curing speed; Good wetting and leveling.
The UV monomer can be cured only when it is irradiated to the glue solution by ultraviolet light, that is, the photosensitizer in the shadowless adhesive will be bonded with the monomer when it is exposed to ultraviolet light. Theoretically, the shadowless adhesive will not cure almost forever without the irradiation of ultraviolet light source. Ultraviolet rays come from natural sunlight and artificial light sources. The stronger the UV, the faster the curing speed. Generally, the curing time ranges from 10 to 60 seconds. For natural sunlight, the ultraviolet ray in sunny weather will be stronger, and the faster the curing speed is. However, when there is no strong sunlight, only artificial ultraviolet light source can be used.
There are many kinds of artificial ultraviolet light sources, and the power difference is also very huge. The low-power can be as small as a few watts, and the high-power can reach tens of thousands of watts. The curing speed of shadowless adhesive produced by different manufacturers or different models is different. The shadowless adhesive used for bonding can only be cured by light irradiation. Therefore, the shadowless adhesive used for bonding can only bond two transparent objects or one of them must be transparent, so that ultraviolet light can pass through and irradiate the adhesive liquid; Apply UV shadowless adhesive to one of the surfaces, close the two planes, and irradiate with an ultraviolet lamp with appropriate wavelength (usually 365nm-400nm) and energy or a high-pressure mercury lamp for illumination. When irradiating, it is necessary to irradiate from the center to the periphery, and confirm that the light can indeed penetrate to the bonding part.
Post time: May-19-2022
