UV varnish selection
There are many kinds of UV varnishes, which are divided into flexible UV varnish, wear-resistant UV varnish, recoatable UV varnish, yellowing resistant UV varnish, high adhesion UV varnish and low volatility according to product quality and functional requirements. UV varnish. Each UV varnish has a suitable product, but it also has certain application limitations. In general, printing companies have the misunderstanding that UV varnishes require all the properties, both flexibility and wear resistance; both surface recoating and scratch resistance. Of course, all ink suppliers want to find a product that has all the properties, but because the structure of the raw materials determines the flexibility and wear resistance of UV varnish is contradictory, recoating and scratch resistance are in conflict. Therefore, it is impossible to have a versatile UV varnish, only the most suitable UV varnish.
Therefore, it is necessary for the printing company to rationally select UV varnish. Some products have complicated post-press processing. After UV glazing, the printed products need to be processed by die cutting and indentation. At this time, it is necessary to select a flexible UV varnish. However, it should be noted that the flexible UV varnish uses a monomer and a prepolymer having a long flexible chain length. Since the degree of crosslinking of the polymer is small, the flexibility of the cured film layer is good, but the reaction speed of the cured film formation is relatively Slower, as the degree of cross-linking of the polymer increases, the mechanical strength and hardness of the UV varnish will increase, eventually losing flexibility and becoming brittle. Therefore, the better the flexibility of the UV varnish, the slower the curing speed and the lower the surface hardness, which may result in poor curing after printing, adhesion on the surface of the printed product, and easy scratching in the paste box.
In addition, some printed products need to be subjected to finer finishing processes such as hot stamping and paste box after UV glazing. At this time, recoatable UV varnish can be selected. The reason why the hot stamping can be realized on the surface of the recoatable UV varnish is because the resin used is matched with the hot melt adhesive in the electrochemical aluminum, and the reaction speed of the resin is slow, the shrinkage rate after curing into a film is small, and the surface tension is low. High, the surface is soft. Therefore, the better the hot stamping effect of UV varnish, the better the flexibility, but the surface wear resistance, scratch resistance will be worse, the curing speed is relatively slow, and there are also poor curing after printing, adhesion of printed surfaces, The risk of scratching when pasting the box.
The wear-resistant UV varnish uses a resin having a high crosslink density and a high reaction speed, and therefore has the advantages of high surface hardness and good wear resistance, and such resins have a fast curing speed and a large shrinkage rate after film formation. The surface tension is low and the surface hardness is high. Therefore, the better the abrasion resistance, the higher the surface hardness of the UV varnish, but the worse the surface recoatability and flexibility, and the risk of poor color and adhesion may occur in the paste box.
Since UV varnish has different surface hardness and flexibility under different light-solid conditions and temperatures, it is necessary to select a suitable UV varnish in combination with the printing process.
Platic Hand Sanitizer Dispenser
We are the company specializing in manufacturing hotel supplies. Main products are hand push soap dispensers, automatic Sanitizer Dispensers, paper dispensers, hand dryers, hair dryers, Trash Bins, etc. Most of our products have certificates like CE, UL, GS, ROHS. With moulding workshop in house and experience techinicians, we accept OEM ODM products.
automatice soap dispensers,Liquid spray soap dispensers,Foam hand soap dispensers
TAISHAN YUEXIN INDUSTRIAL GROUP LIMITED , https://www.gdmetalproducts.com