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Home  Products Inkjet Media
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Tips for Edge Sealing of Inkjet vinyl Prints
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The Problem : |
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More often than not it is found that the laminated vinyl prints mounted on any rigid or flexible substrates have tendency to delaminate particularly in humid and hot conditions. This leads to the lamination film peeling off along with the image, leaving the base PVC film intact on the mounting substrate OR formation of visible blisters between the base PVC film and the lamination film. |
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| The print providers and the media manufacturers around the world have done a considerable amount of research and the main reason behind this has been found to be the water seepage into the laminated vinyls. This is possible either in cases of direct exposure of prints to rains in the outdoor applications or simply the moisture absorption through the edges of the laminated vinyls. The Cause : |
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The vinyls used for the inkjet printing are manufactured by coating the base PVC film with a fine coating which is designed to absorb the water based inks received on its surface. Hence it has an inherent property of absorbing water and moisture coming in contact with it. |
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The Cure : |
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The only way therefore to prevent the water absorption by the coated vinyl after printing is to avoid contact of the two. In other words prevention is better than the cure. In case of a properly laminated print the only way for water to infiltrate the print is through the edges and hence the effective way to prevent water seepage is to seal the edges. This can be done either by Edge sealing with larger laminate or by Edge sealing with Lacquer / Varnish or Silicone. |
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The Method 1 : Wrap around
Step 1 :
While designing the layout of the image to be printed on the vinyl ensure that an unprinted border of about 10 mm to 20 mm is left around the print on all four sides.
Step 2 :
After printing, cut the unprinted edges of the vinyl straight ( with a very sharp cutter/knife ) - do not cut through the release paper. This is often referred to as 'Half Cut'.
Step 3 :
Peel off the unprinted part of the vinyl from the backing leaving release paper intact. ( Refer : Fig 1. )
Fig 1 : Method 1 - Edge sealing of Inkjet vinyl print.
Laminate the whole print edge to edge ( including the left out release paper ) with pressure sensitive cold laminate. This will ensure that an extra lamination border is available. ( Refer : Fig 2. )
Fig 2 : Method 1 - Edge sealing of Inkjet vinyl print.
Step 4 :
While mounting the print on polycarbonate or sun-board this extra lamination border should be turned around all the edges and pressed uniformly on the backside. ( Refer : Fig 3 & 4 )
Pasting additional 20 mm lamination strip/adhesive tape over the edges on the backside should further strengthen edge sealing thus done.
Fig 3 : Method 1 - Edge sealing of Inkjet vinyl print.
Fig 4 : Method 1 - Edge sealing of Inkjet vinyl print.
Caution!!!
While mounting and transporting the print at the site ensure that the sealed edges are handled with care avoiding any rough sliding along the edges against the rough surface. Ensure that edges still remain fully covered with the laminate when the print is put in the final position. Needless to say the prints edge sealed in this manner must not be cut on the site on any side or corners to make a perfect fit. It is advisable to therefore take a perfect size print keeping the dimension and the needs for edge sealing in mind to avoid any onsite trimming.
Method 2 : Using larger mounting substrate
In cases where it is possible to use a board of size larger than the print, the edge sealing can be achieved by simply using the laminate with an extra border of 20 mm larger than the print size. In such case even edge-to-edge printing of vinyl is possible.
Please follow the Steps 1, 2 and 3 as given in Method 1.
Fig 2 : Method 1 - Edge sealing of Inkjet vinyl print.
Step 4 :
Mount the laminated print directly on the mounting surface, at the center, leaving a border of 20mm on all sides. Firmly paste the extra lamination edges on the extra border of mounting substrate. ( Refer : Fig 5 & 6 )
Fig 5 : Method 2 - Edge sealing of Inkjet vinyl print.
Fig 6 : Method 2 - Edge sealing of Inkjet vinyl print.
This method is most effective as it completely isolates the printed vinyl edge from external environment by about 20 mm of sealed border.
Caution!!!
If at all holes are required to be drilled into the laminated print while mounting, then ensure that the same are sealed completely with suitable sealant after securing the print on the structure in the final position.
Though edge sealing with lacquer/varnish/silicone is possible it suffers from the following limitations :
- The adhesion of the lacquer is dependent on the substrate and may need a primer coating.
- The finish of lacquer may affect and alter the appearance of the print.
- If the lacquer is not absolutely clear ( water white ), it may affect the appearance of the print.
- The durability of some lacquers is limited in outdoor conditions and they may tend to yellow or crack.
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