Paper, varnish and primer for UV coating

[silviuv]

Hello !

For my small print-shop I just bought a machine for UV coating. The machine is not very advanced and it's small (table sized) with 2000W UV light and ~1500W IR (picture). I also bought 25kg Fujifilm DS 2346 UV Glossy coating varnish (it's main property is "low yellowing" and the only with solvent content of 20%, while others are "allround/standard" or "narrow web application" and solvent content of under 1%). BTW, it smells awful.

The business who sold me the machine doesn't have any clue on how it should be used, because clearly they are using it wrong (their smooth finish samples have the "orange peel" texture).

The other day when they installed it, i found out that on uncoated (thick laser printer Mondi paper) and matte-coated (large format inkjet reel) paper the varnish is absorbed by the paper. On glossy media it looks better, but it has pronounced gloss differential according to the density of the toner.
I called the coating supplier and he told me that before UV coating the paper needs to be primed; another piece of information he hasn't told me. I think he is trying to lead me into buying another expensive (useless) 25kg canister, just because it's in stock.

So my questions are:
1. can UV coat uncoated and matte coated paper ? how ?
2. can I get better results with the glossy media ?
3. what properties should the UV coating have ? do you have any brand/model recommendations ?
4. do I need a primer ?
5. should I use a water based coating ?
6. are there any options that doesn't smell as bad ?

I really need to make this thing work. It was a big investment for me and by now it looks like such a bad ideea .
Thank you in advance !

Silviu

 

[OkiTech]

Hi Silviu. I do not own a UV coater yet but to the best of my knowledge - you can't UV coat Uncoated paper.
You should get a better results with coated stocks.
The brand/name question could be irrelevant as somebody from different continent may advise you something that's not available in your region.

 

[Kees]

Hi, it is possible in screenprint with a special uv coating with good results, of corse it has not that high gloss on uncoated as on coated, if this could be done on your little machine I do not know. Ask a sreenprinter for detail information.

 

[countmachinery]

Silviu,

We manufacture a UV Coater and have some pretty good experience in UV Coating. I have never had a customer who purchased one of these tabletop machines give me positive feedback on them. Orange peel effect may be due to the fact that there is not enough "dwell time" or time between the fluid being applied and being cured. Or it could be a bad application process or too much fluid being applied. That being said I can answer most of your questions for you.

So my questions are:
1. can UV coat uncoated and matte coated paper ? how ? Not really. We only recommend coated stock. Like you found, uncoated stocks absorb the fluid into the paper fibers and give a splotchy look. Sometimes running the sheet multiple times will "fill in" the splotches, but in general you will never really get a smooth shiny finish.
2. can I get better results with the glossy media ? Yes. 100% on just about any coated stock.
3. what properties should the UV coating have ? do you have any brand/model recommendations ? This depends on the print engine and the application. some are needed for adhesion, max shine, matte finish or semi gloss, max protection, etc. There are a ton of UV fluid manufacturers.
4. do I need a primer ? I've never heard of this and have no experience with "primer", but we never use one and are able to coat perfectly.
5. should I use a water based coating ? Our machine is not designed for a water based coating as the consistency is thin and messy and our results have been mixed with curing. The IR system does more curing than the UV system at that point.
6. are there any options that doesn't smell as bad ? Some coatings have stronger odors than others. It depends on the manufacturer. Most of the coating we use have very little smell to them.

Please let me know if there is anything else I can try to answer or help you with. I have no experience with the machine you have but I may be able to help you with trying to make the best out of it.

Frank Flores
Count Machinery
UV Coating Machine, Numbering Machines, Perforating Machines, Scoring Machines, Creasing Machines By Count Machinery Company