posted
Hi Everybody! We have been screening vinyl banners for over 20 years using Naz Dar gloss vinyl ink. Prep has always been the same, wipe with alcohol, print through 200 mesh monofilament mesh, air dry.
The latest job we printed followed this same proceedure. Before shipping, we did random "tape testing" and all was good.
A couple of months later we got a call from the customer that the image was coming off.
We had them return a banner that had been in use and one that had been in-stock. The "tape test" on both pulled the image off. I again printed a test area on both these banners ("corp."), and again the image has passed the "tape test" (for now). The banners were printed on both sides, and image failed on both sides.
Now, the customer supplied the blank banners, so I don't know the manufacturer or the amount of plasticizer they use. The blanks were very soft and flexible.
I contacted Naz Dar technical support and they agreed that the ink choice, prep and printing methods were the correct choice. They felt the vinyl banners had an excess of plasticizers used in the manufacturing process. So even though the initial adhesion was good, as the plasticizers migrated to the surface, the bond between the ink and the banner broke down.
Has anyone had a similar problem or any comments on this situation. Also do you have any thoughts on coating the blanks with a barrier prior to printing.
posted
There are vinyls and banner materials comming out of China that look and handle quite nicely...BUT...do not hold up very well! They seem to be over plasticized. Evidentaly the vinyl resin that they use is much too rigid, therefore requiring more plasticizer, making it useful ONLY for short term quickie signs.
-------------------- Si Allen #562 La Mirada, CA. USA
(714) 521-4810
si.allen on Skype
siallen@dslextreme.com
"SignPainters do It with Longer Strokes!"
Never mess with your profile while in a drunken stupor!!!
Brushasaurus on Chat Posts: 8831 | From: La Mirada, CA, USA | Registered: Nov 1998
| IP: Logged |
posted
I agree that it is probably the plasticizers causing the problem. I use vinyl screen inks almost exclusively on all my banners, tents and vinyl curtains, but I either paint it on or mask and spray using Lacquor thinners rather than screen print.
The thinners eat thru the gloss surface layer providing an excellent hard wearing bond for the ink. Mask and spray is also a more cost effective method on single or small repeats.
Duncan, you asked if there was a way of coating the surface first. It may be worth testing a coat of clear ink spayed on with laquor thinners thru a HLP gun.
The only time I had any adhesion problems was when THE CUSTOMER PROVIDED THE BANNERS hahahaha. Nothing, I mean nothing stuck to them! Turned out they were made from specialy formulated vinyl that was designed for grain storage bins.
[ December 23, 2002, 04:14 PM: Message edited by: Jon Butterworth ]
posted
Duncan If I read correctly that sign reads wide load,...did the customer by chance have the truck washed with a solvent or acid base wash during it's many travels? It also looks like they may have a few tire tracks on them,....Ya can't warranty abuse,....Those banners flap like crazy at highway speeds against what ever they are attached to,usually the front bumper of a big rig.
-------------------- fly low...timi/NC is, Tim Barrow Barrow Art Signs Winston-Salem,NC Posts: 2224 | From: Winston-Salem,NC,USA | Registered: Nov 1998
| IP: Logged |
![[Eek!]](eek.gif)
![[Smile]](smile.gif)
Printer-friendly view of this topic