Bubbles on out gassed polycarbonate

[stickerhed]

I'm hoping someone can help us. We made 14 signs out of .177" clear polycarbonate with full digital print 2nd surface. The poly was outgassed over the weekend, and in some of them more than a week. 2 days outside and the rash of bubbles in the picture has appeared. We used 3M 3630-114 transparent translucent for the prints. They were printed on an HP 700W (3 layer sandwich print). I've been in the sign business since 1990, I've never had to out gas longer than 24 hours. The customer brought in a sample that was made like this, although they probably used different printers and vinyl. The sample they brought in is also polycarbonate.

 

[citysignshop]

well, I think we've all experienced something like this; a few thoughts if helpful....

Are there specs for drying from the polycarb manufacturer? What I've seen is pretty dramatic....hanging with forced air flow at an elevated temp like 125F or 250F for flash drying...( more common in production line mfg.) then vinyl applied immediately the sheet is cool, so moisture isn't resorbed.
Many poly sheets have a hardened surface on one side for scratch resistance, so vinyl applied over the back-2nd surface- will partly 'seal' the sheet from moisture changes.
you're in Wisconsin?....just how 'dry' is the air 'outside' when processing these sheets?

If not in a high-impact or security risk zone, does this really need to be poly, or will hi-impact HD acrylic work?

best of luck trouble-shooting this!

 

[JSIGN]

Sorry for you - what a mess.
I was told that plastic is made "plasticy" ( flexible ) by using plasticizers ( oily resins ) in the formulation, and polycarbonate, being among the most "plastic" of plastics certainly uses a lot.
I was also told* ( *not saying I know these things ) that there is a rejection / life stage called plasticizer migration where the plasticizer resins leech out to the surface which can cause adhesion problems.
I was told that a good prevention would be to do a quick burn over the entire surface with a propane torch to hopefully burn away any such oils, before solvent prep cleaning.

Honestly though, we don't always do that, yet have had no problems over the last decade or more - I suspect that some plastics are cheaper, or maybe sign suppliers are taking care of that for us ?

Hope things get better for you.

Jim

 

[DL Signs]

Been having issues (hit & miss) for a couple years now. Nothing has changed on our process, just seems like the poly we're getting from the same sources, same brands, are just getting more problematic to work with.

 

[Texas_Signmaker]

I heard the proper way to dry it is to heat the whole sheet up to 200 something degrees for 10-15 mins. Like any shop is doing that.