+What is laminating?
Laminating is a finishing method in which a “film” is applied to the face of a printed graphic. Laminating can provide colour enhancement, durability, variety of finishes, and reflective qualities of a printed graphic. Some films will also provide protection from UV rays, along with adding value and longevity to your graphic.
+What is the difference between laminating, encapsulating and mounting?
Laminating is adding protection or a desired look to a print. Encapsulation is sealing the print above and below with a heat activated laminate. Mounting is applying an image to a rigid substrate.
+Why use cold (pressure sensitive) films?
If an image or printed media is sensitive to heat or the surface has adhesion problems, it is preferable to use pressure sensitive films. Generally films and adhesives for long term outdoor use are pressure sensitive.
+Why use hot (heat activated) films?
Heat activated films form a better and more permanent bond to suitable material surfaces and are generally less expensive than pressure-sensitive films.
+Why use water-based adhesives?
Advantages of water based adhesives:
- Lower cost solution than solvent
– Suitable for both lamination and adhesive films
+Why use solvent-based adhesives?
Advantages of solvent based adhesives:
– Suitable for outdoor use and long term applications
– Can include high level of UV protection into adhesive
– Suitable for both lamination and adhesive films
– The high tack qualities of the adhesive are good for low surface energy substrates such as polystyrene.
+Why use hot melt adhesives?
Advantages of Hotmelt Adhesives:
– Not affected by moisture in application
– Low cost
– Short term outdoor use
– High adhesion
+Why use polyester films?
Polyester films are durable dimensionally stable films that are generally used for gloss lamination films as they are able to achieve the highest gloss level available.
Polyester films have a high melting point.
+Why use PVC films?
PVC (vinyl) based films are best suited for top coating vinyl media and substrates. They will provide similar rates of expansion/contraction to the media they are applied to. Some vinyl based films offer high levels of UV protection.
+What is laking?
Laking is the effect of a lake or puddle in an adhesive coating. The area reflects more light due to the release liner or coating technology. Laking has no effect on the finished application.
Laking can be caused by one of two factors. 1) bad application of adhesive by the manufacturer. 2 ) films with a high (greater than 6ml) adhesive coating.
Where the adhesive ratio is high, laking can be caused when the roll laminator is heated and liquifies the adhesive, the rolls (nip point) are inconsistent and/or uneven causing the liquified adhesive to spread out unevenly.
+What is piping?
Piping is expansion or contraction of release liner or media due to change in environmental moisture balance.
+What is silvering?
Silvering is the speckled appearance of a laminated print or air bubbles trapped under the lamination film. Silvering may not be a permanent effect. It is usually reduced with hot or heat–assisted lamination.
+What is shrinkage?
Shrinkage is a condition that can occur to both Laminates and Adhesives. The root cause for this condition is derived from two culprits: excessive tension and/or too much heat applied during the application which can cause “stretching” to occur.
Once the graphic is “finished” all looks well, within a short time frame you will see that the Laminate has “shrunk” and has pulled away from the edges of the graphic, the laminate appearing to be “smaller” in size than the graphic. Adhesive “shrinkage” will also be quite noticeable, causing graphics to pull away from the edges of their substrates and in some cases causing the graphic to “pop” off of their mounting substrates.
+How do you know if your adhesive is water-based or not?
Place a laminate sample into a glass of water. The film turning cloudy after 10 minutes indicates it is water based. If the film colour remains unchanged it is likely to be solvent based.
+Why is my laminate not sticking to the image?
Several reasons could be possible:
- The laminate is not compatible with the media or ink being used
- The temperature is not hot enough
- Not enough pressure has been applied
- The print was not dry before lamination
+How long will my print last if I laminate it with a UV protective laminating film?
It is very difficult to put a life span on a print due to all of the environmental factors as well as all the different types of ink and media characteristics. Generally, the colour fade time can be as much as doubled by using a UV protective film.
+Can I roll up a large print if it is laminated with a pressure sensitive film? Will it “tunnel”?
You may roll it up as long as the image is first allowed to cure for 24 hours and the inside diameter of the loosely rolled up image remains greater than 6 inches (general guide) and is rolled ‘Printed Side Out’. If rolled up too tightly, separation may occur between the image and lamination creating a “tunnel”.
+What is a high temperature heat activated film and a low temperature heat activated film?
High temperature laminates will usually require roller temperatures of 99-112°C or above, while low temp films will activate at 82-96°C roller temperature.
+What is a release liner?
A release liner is a protective sheet that is covering the adhesive layer on a film product. This liner is removed and discarded while running the film through a laminator. If you are creating a decal, the release liner is removed during the mounting process.
+What is the ‘film to adhesive ratio’ and what is its relevance?
When discussing film composition and its thickness, the industry standard is to refer to ‘film to adhesive ratio’. This ratio represents how thick the film is and how thick the adhesive is that has been applied to the film. If a 10mil film has a 7/3 film to adhesive ratio which means that the film thickness is 7mil and the adhesive on it is 3mil thick.
Thick coatings of adhesive add a slightly yellow tint to the film. Some professional printers account for this through colour correction before lamination to hit exact colours. The slight yellowing is not usually noticeable or a problem. For this reason, better quality laminates will have thick film and low adhesive ratio’s to provide optimum optical clarity.
+What pressure should I set my roller to?
As a general rule of thumb, the thicker laminates require a lower pressure required.
For example, if using a 3mil pressure-sensitive laminate, run the laminator at approximately 80PSI. When using a 10mil pressure-sensitive laminate, run the laminator at approximately 50-60PSI (if using a pressure gauge type laminator).
+What is curing time?
Once completed, allow the laminated print to lay flat for a minimum of 2 hours prior to rolling or trimming for proper adhesive curing. When possible allow the laminated print to cure for 24 hours – especially important when laminating prints for outdoor use.
+Finishing and Transporting Laminated Prints
When cutting or trimming a laminated image, always cut the side with the thinner or softer material first using a freshly sharpened blade with a straight edge. For transport or storage, roll the laminated graphic with the thinner or softer side facing out with a resulting roll diameter no less than 12 inches (general guide).
+Hot spots on the rollers
If the laminator is left idle and the rollers are not moving, the rollers will develop “hot spots”. This will create problems during lamination such as “silvering” and/or “out gassing”. If you need to keep your laminator at operating temperature when idle, keep the rollers moving in order to maintain even heat throughout the roller’s surface.
+What is Blistering?
Blistering occurs primarily with thermal laminates generally due to excessive heat. The ink underneath the lamination film bubbles creating air pockets. This can be resolved by:
- Reducing heat
– Increasing laminating speed
– Using pressure sensitive laminates instead of thermal laminates