Wanted- a non tacky photopolymer emulsion

[Atownsend]

Thanks for the info!! Will be implementing the powder trick until we have time to play with some of the suggested emulsions here. Tackiness has been a big problem for us. Trashed 10 of 20 positives today.

[Nation03]

Baby powder helped save films for repeat orders. Ulano Orange had minimal tack and my local sales rep wants me to try Ulano Blue. Saati PV has been the tackiest so far. Cryocoat wasn't too bad but I think Ulano Orange was the least tacky that I've tried this year so far.

[alan802]

Thanks for the info!! Will be implementing the powder trick until we have time to play with some of the suggested emulsions here. Tackiness has been a big problem for us. Trashed 10 of 20 positives today.

You may find the powder trick to be sufficient if you like your current emulsion a lot.  It's one of the few "bandaids" I don't mind doing around here.  I did spend hours upon hours trying to figure out how to get regular emulsions from eating our positives and now I would rather find a good emulsion that we like, that has minimal tack and use the powder. 

[3Deep]

CCI HXT you'll love it

[Frog]

Thanks for the info!! Will be implementing the powder trick until we have time to play with some of the suggested emulsions here. Tackiness has been a big problem for us. Trashed 10 of 20 positives today.

You may find the powder trick to be sufficient if you like your current emulsion a lot.  It's one of the few "bandaids" I don't mind doing around here.  I did spend hours upon hours trying to figure out how to get regular emulsions from eating our positives and now I would rather find a good emulsion that we like, that has minimal tack and use the powder.

I sometimes cringe when the term "bandaid" is used as a temporary or even half-assed fix because, in the real world, actual bandaids are often exactly the fix one wants. Not every cut requires sutures.

[CBCB]

We tried Chromatech WR and it was insanely sticky. Film was fused to the emulsion.

We're on Ulano Orange in the meantime.


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[Nation03]

Not sure if this one was mentioned yet, but I'm currently using Ulano Blue and there is zero tack on even the most humid days. I haven't been using baby powder with it and the films come off perfectly.

[domineight]

Why don't you just turn the heat up in the drying room.  The emulsion can only be tacky if it's full of moisture.

[tonypep]

Not necessarily true

[domineight]

Not entirely,  but highly probable.

Click the fan heater on high in the morning, direct the flow of warm air across the rack of screens intended to expose, but don't touch them till 10am. I'd  hazard a guess there would be a noticeable improvement.

I'll take a stab and say the tackiness in most part is inkjet film sticking to the stencil. Why?

[Admiral]

The heat from exposing and using the glass (keeping a lot of the heat in) I'm sure adds to the problem.  Cooling down the exposure unit better / not using it as fast between screens (see if you can add coating at the same time as making screens?) would help.

I'm glad to be rid of that problem with CTS.  I do remember some films sticking really bad when the temp and humidity was really high in the summer.

[domineight]

I have the same. Film sticks when humidity climbs up to 50%+  and first thing in the morning. I have a 10'X10' room with a domestic dehumidifier that runs 24h and the little fan heater gets clicked on high first thing in the morning.

If I can maintain a ratio of 30% humidity and 35 degrees in heat, film sticking isn't an issue. Outside of that I'm blasting black inkjet film off my stencil or peeling the frame off the glass regardless of emulsion.

I just make sure I'm setup for the following morning the previous afternoon to overcome the gap in waiting for the heat to climb.

I've been using a Roland ecosol printer for film for the last month through necessity , I don't have that sticking problem while I'm using this.

Generally I'll use Ulano QTX or QX1, Foteco 1850 solo.
M&R trilight 3kW.

I might run things hotter in the drying room because I'm generally impatient anyway, but ruining film I might need to expose again drives me nuts, as does washing the black ink out of my exposed stencil. And heat is how I overcome it, it's not excessive heat either IMO.

It would be interesting to hear how someone with something like a vastex drying cabinet or that type of generic screen cabinet gets on and whether they suffer from this specific problem.

[Colin]

The sticking is generally a chemistry issue.

While yes, humidity will always play a roll.  If you have eliminated the moisture issues, what remains is the plastisizers in the emulsion.  Under heat, these plasticizers are tacky and grab at all films.  Waterbase films exacerbate the issue compared to silver or laser films.

Tldr:  If your screens have an average of 35% internal humidity and they are still sticking during exposure, either change your emulsion or use baby powder/talcum powder.

[Rockers]

Why don't you just turn the heat up in the drying room.  The emulsion can only be tacky if it's full of moisture.

I don`t think so.

[domineight]

Why not?

You didn't elaborate on the effect of tacky stencils, or what it's doing that's causing you to look for a cure. If it's just a case of everything working as it should then that's probably not a problem.
Reading what others have said they have film sticking to emulsion, destroying their positives. Perhaps wrongly I'm assuming inkjet positives.

Do they have the same problem using image setter film or solvent film? If these two films are sticking, but peeling away unharmed and the stencil is still washing out fine, that's not a problem is it?

I guess to answer the question without elaborating. Ulano QTX, is fine, no sticking problems what so ever. No need for talcum powder, the emulsion never sticks to glass, your inkjet positives are perfectly fine and peel away unharmed, with only the slightest hesitation after having been compressed with vacuum for as long as it takes to expose whatever I'm exposing. Actually I don't have a problem with emulsions being tacky at all, at least not all the emulsions I've tried.

If I was to elaborate on that, I only ever achieved a non tacky emulsion (regardless of make up), that would cause problems in keeping inkjet film in good reusable condition, when I eliminated moisture from my stencils as best I could. In saying that, I might just be lucky.

I'm not going to delve too deeply into it, I don't know the science. I just know inkjet film isn't sticky, but when I lick my thumb and grab an edge of inkjet film it's sticks to my thumb like a bastard, and that tells me moisture effects inkjet film and if any moisture comes in contact with the inkjet film and is compressed under pressure for a few minutes, then the film is going to stick to whatever it's in contact with like a self adhesive label. Likewise, glass doesn't have any adhesive properties so any problem associated with emulsion sticking to glass would have to rightly boil down to emulsion, so why not look at moisture content of the stencil as a reasonable cause of tackiness there too.

That, or it seems folk swear by talcum powder with no ill effect and minimal fuss, I'll give it a go myself sometime.