What are the component raw materials of light-curing UV coatings?
Ultraviolet curing (UV) coating is a new type of environmentally friendly coating. It has an extremely fast drying rate and can be cured in just a few seconds by UV light, with a high production efficiency.
UV cured coatings are mainly composed of oligomers, reactive diluents, photoinitiators and additives.
1. UV Oligomer
The film-forming compound is the main composition of the coating, which is the fluid component in the coating. The coating film performance, construction performance and other special properties of the coating mainly depend on the film-forming compound. UV coating film-forming compound is oligomer, its performance basically determines the construction performance and light curing rate of the coating before curing, the coating film performance and other special properties after curing.
UV coatings are mainly free radical light curing systems, so the oligomers used are various types of acrylic resins. Cationic UV coating oligomers are epoxy resins and vinyl ether compounds.
2.Active diluents
Active diluents are another important component of UV coatings, which can dilute and reduce viscosity, and also have the ability to adjust the performance of the cured film. The acrylate functional monomer has high reactivity and low volatility, so it is commonly used in UV coatings. acrylates are commonly used as active diluents for UV coatings, and in the actual formulation, single, double and multi-functional acrylates will be used together to make their performance complementary and achieve good overall effect.
3. Photoinitiator
Photoinitiator is a special catalyst in UV coatings, it is an important component of UV coatings, to determine the light curing rate of UV coatings.
For colorless varnish UV coatings, photoinitiators are often used 1173, 184, 651 and BP/tertiary amine. 184 high activity, low odor, yellowing resistance, is the preferred photoinitiator for yellowing resistant UV coatings, in order to improve the light curing rate, often used in conjunction with TPO.
For colored UV coatings, photoinitiators are to use ITX, 907, 369, TPO, 819, etc.. Sometimes UV coatings in order to reduce oxygen blocking, improve the light curing rate, often into a small amount of active amine.
4. Additives
Auxiliary agent is the auxiliary component of UV coating. The role of additives is to improve the processing performance of coatings, storage performance and construction performance, improve the film performance and give the film some special features, etc. UV coatings commonly used additives are defoamer, leveling agent, wetting and dispersing agent, adhesion promoter, matting agent, resist, etc., they play a different role in UV coatings.
Is the smell of UV printer toxic?
UV printer is a kind of printing equipment that responds to the green environment. Due to the uniqueness of the UV printer curing method, in the UV light curing process, it is inevitable that some odor will be generated. Many friends who have purchased or plan to purchase UV printers, there are such questions about the smell: whether the smell is toxic, how to deal with it?
Of course, the user’s concern about the smell is normal, especially those who are not too clear about the UV printer printing process, the smell will be more obvious when using a flatbed UV printer to print large-format materials. To answer the above questions, we should first understand the composition of the UV printer ink. After all, the source of the odor lies in the UV ink.
UV ink is mainly composed of photoinitiators, reactive diluents, oligomers and various additives. UV printer ink layer is formed by: photoinitiators absorb UV light to produce free radicals or cations, causing reactive diluents and oligomers polymerization cross-linking reaction. Odor mainly from the UV ink acrylates, but also a small amount from the additives. Odor will slowly fade in a short period of time eventually disappear, and really harmful to humans and must pay attention to heavy metals such as lead, cadmium, mercury, hexavalent chromium, as well as polybrominated biphenyls, polybrominated diphenyl ethers, phthalates and other volatile high, odor, allergy-prone substances content exceeds the standard. At present, the regular manufacturers of ink can provide the above substances test reports.
Since we know the composition of UV ink, the source of odor and the focus to detect which harmful components, we only need to do the following in the actual product selection, printing production, you can not worry about poisoning or other serious harm to the human body occurred. First of all, we must choose a guaranteed brand of UV printer manufacturers, choose their compatible ink, it is best to let them issue test reports; secondly, regardless of whether the smell is toxic, for insurance and operator comfort considerations, the use of the production environment to have good ventilation, the conditions of the unit can be configured with some gloves, masks and other protective equipment; finally, the printing of waste to facilitate recycling or disposal To avoid “secondary pollution”.