Drip off(texture-gloss combo) effect on UV offset press

[falit pandya]

hello Everyone,

we have a 6 color plus coater machine with IST UV. 1 lamp after 6th unit and 2nd end of the press. We have good success in printing 5 color with gloss or 6 color with gloss UV, however, whenever we try to do Drip-off effect we face a problem. Our entire sheet gets the texture or grainy effect, even places where its not suppose to be. We run matt coating in the 6th unit and gloss UV in the coater. Instead of getting texture effect only in those areas specified in the plate of the 6th unit(which has matt), our entire sheet comes with texture. now, i believe the problem is with our chemistry. When we turn all the units off and only drip-off is done, result is perfect, but when we print 4 or 5 color prior to Drip-off, result is not is fully textured sheet. Can someone please help of guide me in the right direction. we have changed multiple ink suppliers and tried every combination possible, but have hit a dead end…..

 

[mazengh]

Try printing the 4 or 5 colors and cure them, then go a second pass and do the drip off... see if it works...

 

[Cornishpastythighs]

You will probably need to use a combination of Reticulating Matte Varnish printed in the 6th unit and then a special Gloss UV coating. Make sure you have the correct BCM for your anilox and do not cure the Matte varnish after the 6th unit. Let the wet matte varnish do it's job of reticulating with the Gloss coating and then use your end of press lamps. This will give you a smooth gloss areas and a textured area where you need it. Your textured areas are defined by the litho plate in the 6th unit and then an overall gloss coating is used. Used this method for many years with good success. Sun Chemical has some good reticulating products but others do as well.
What you are missing though is a UV lamp after unit 5 to cure the inks. The coatings will tend to 'dive into' the uncured ink and minimise the effects
good luck

http://www.actega.com/terra/products...-coatings.html

 

[falit pandya]

hi,

sorry for the delayed response. so finally we have managed to get some success with Drip-Off, we did get a new roll made, but that didn't solve the problem. we called in an expert from Actega who added couple of chemicals in the UV gloss and Matt varnish to get the result. i don't think we are 100% there, but a salable sheet is achieved. Thanks for all the help.