Due to various reasons,UV ink will not be completely cured.What are the factors that affect the curing degree of UV ink?
1.The variety and color of the material
Some color materials have special ultraviolet absorption properties,and the curing of these materials will slow down.In addition,the same kind of material will also be different due to different grades.
2.Color of ink
Those pigments that specifically absorb ultraviolet rays will slow down,and the more they contain,the stronger the tendency.Therefore,the concentration of UV curing ink has a certain degree of concealment.Especially when the color is applied,all kinds of primary ink has no curing problems,but the color matching ink will have bad curing problems.In particular,high concentration of while and dark colors(black,blue,and others)should be fully observed.
3.Light curing initiator
The addition of photocurable initiator is an effective way to improve the curing property.However,excessive addition of photocurable initiator will hinder curing.In addition,there is residual odor after irradiation.Please observe the specified amount of added(less than 4%)
The thinner the printing film,the better the curing.In general,colored ink can get sufficient curing performance in the film thickness range of 10-12 um.If the film thickness exceeds 15 um,there will be a phenomenon of poor adhesion due to poor curing.Varnish printing ink,more than 100 um thick film,its curing property is no problem.Some customers reflect dark color curing completely,but light color is wet.Because this customer is equipped with mercury lamp.mercury and other short wave ultraviolet rays will form ozone,light color part because of thin,the area of contact with ozone,the ink in the light initiator has not occurred the curing reaction,the ozone oxidation,and then repeated,will not dry.
5.Ultraviolet intensity and accumulation of light
The overall judgement of sclerosing is determined by accumulated light.However,the most important factor of internal hardening is the intensity.When the UV intensity is low,increasing the irradiation time and increasing the amount of light can not improve the internal hardening of the bottom of the printing film.In this case,please reduce the height of the lamp,or switch the power of the lamp to the problem of high power handing.
6.The temperature of irradiation
The ambient temperature of UV irradiation has a great influence on curing of UV ink.For heated,expandable materials,higher temperature is beneficial to curing,because the absorbable ink increases adhesion after expansion.But this will also bring another problem.Too much heat will destroy the solidified good ink layer again and become crisp.
Different measure can be taken for different materials,such as water washing,dust removal,alcohol scrubbing,drying,corona,flame and so on,For some materials,such as glass,pure acrylic,and metal,UV ink has no reaction with it at all.The adhesion must not be ideal.As a linking agent,the coating reacts with the ink and reacts with the material,thereby increasing the adhesion of ink printing on these materials.
Contact: Belinda Tong
Company: HC UV flatbed printer
Add: Floor 1-3, Building 1#, Middle of Puxin Area,Xinlian , Longgang,Shenzhen