UV Inks - Technicalities

[faisal.ta]

Hi
Can we please know the technicalities of the UV Inks. What are the implications it has with temperature. And the normal shelf life of the UV Inks mentioned is 6 months. What happens after that?
The ink being not good adhesive on the foil sheets, does the ink has anything to do with it?
And how can we avoid the ink peeloff from the foil sheets in sheet fed.

Faisal

 

[Cornishpastythighs]

Wow thats quite a shopping list of information you are asking.
Shelf life- Normal shelf life for UV should be anywhere from 6-12 months, This of course depends on the environment it is stored in. If you store this ink in a high temperature area it could 'Polymerize' in a couple of months. Keep it stored in a cool moderate temperature area but not a cold area or you will never get it out of the can. Normal test for Polymerized inks is to put a metal ink knife staight into a can of UV ink and slowly pull it out, if the Knife comes out with clean areas on it the ink is starting to go off. UV ink usually starts to go off from the bottom of the can first. Never put used UV ink back in the can (which should be black so that light cannot get to the ink)
Poor adhesion of UV to foil can be influenced by many things- Poor foil treatment(low Dyne Level), check your substrate with with a Dynes pen to make sure it is within spec.
Poor ink/water balance will interfere with the inks ability to 'stick' to non absorbent stocks.
Carrying too high an ink density. Much better to print 2 hits of say a dense black and cure them rather than trying to carry a thick ink film
Poor UV lamp and reflector maintenance.
Not enough lamp power to begin with. You need a minimum of 500watts per inch with todays Photoinitiators
Inks not designed for non absorbent stock-Ask your ink maker if they have High Adhesion inks.
Well there's some ideas for you to begin with hopefully others will help you.

 

[rmbob]

Uv-inks metallic

Uv-inks metallic

Does the same hold good for metallic offset inks too like uv-offset single pack gold n silver?

Wow thats quite a shopping list of information you are asking.
Shelf life- Normal shelf life for UV should be anywhere from 6-12 months, This of course depends on the environment it is stored in. If you store this ink in a high temperature area it could 'Polymerize' in a couple of months. Keep it stored in a cool moderate temperature area but not a cold area or you will never get it out of the can. Normal test for Polymerized inks is to put a metal ink knife staight into a can of UV ink and slowly pull it out, if the Knife comes out with clean areas on it the ink is starting to go off. UV ink usually starts to go off from the bottom of the can first. Never put used UV ink back in the can (which should be black so that light cannot get to the ink)
Poor adhesion of UV to foil can be influenced by many things- Poor foil treatment(low Dyne Level), check your substrate with with a Dynes pen to make sure it is within spec.
Poor ink/water balance will interfere with the inks ability to 'stick' to non absorbent stocks.
Carrying too high an ink density. Much better to print 2 hits of say a dense black and cure them rather than trying to carry a thick ink film
Poor UV lamp and reflector maintenance.
Not enough lamp power to begin with. You need a minimum of 500watts per inch with todays Photoinitiators
Inks not designed for non absorbent stock-Ask your ink maker if they have High Adhesion inks.
Well there's some ideas for you to begin with hopefully others will help you.

 

[tkemerly]

Metallics (Gold and Silver) usually turn even faster, some formulas in a matter weeks....

Tk