Pages

▼

Monday, March 21, 2016

How Cast Vinyl Films Are Made

Print Friendly and PDF

By Jim Hingst @hingst_jim 
Cast vinyl films begin as a  paint-like mixture of pigments, PVC resins, plasticizers and solvents.

Cast vinyl films begin as a liquid, which resembles paint. This liquid, called an organosol, consists of  pigments, plasticizers, PVC resins, solvents and additives.

Compared to calendered vinyl,  manufacturers of cast vinyl films use more costly, automotive-grade pigments and  heavier and more stable plasticizing oil. The film retains the weightier oil throughout its life, which keeps the film flexible. 

In contrast, calendered vinyl is made using a lighter, more volatile oil. This lighter weight plasticizing oil serves a secondary function by helping lubricate the extrusion rollers during the manufacturing process. However,  because the lighter oil is more prone to leeching out of the vinyl, calendered vinyl over time can become brittle.
When manufacturing cast vinyl films, liquid organosol is coated or poured onto the casting paper. As the paper travels through a 75-ft. oven, the organosol is baked at 400 to 450°F.
In manufacturing, cast vinyl films are baked. As the solvents evaporate in this baking process, the liquid becomes a solid film.
Baking evaporates solvents from the wet organosol, leaving a dry film. In this "fusion" process, the plasticizer bonds with the PVC resin, giving cast vinyl film its strength.
This fusion is the key to making cast vinyl film, because it affects virtually all its properties, such as elongation; modulus (measurement of the stress a material can absorb before losing its elasticity); adhesive anchorage to the facestock; ink adhesion; system durability; shrinkage; and the film's hue and gloss.
The quality of the film’s internal bond depends on the molecular weight of the plasticizers, PVC resin, pigment and additives; the type of solvent used; and the length of the curing process.
Little mechanical stress is created during the casting process, because the organosol merely lies on the surface of the casting paper while the film is fabricated. Consequently, film shrinkage is low.
Cast vinyl's low tensile strength contributes to the film's ability to stretch, and, consequently, its conformability. Therefore, cast film can cover such demanding substrates as rivets, corrugations and textures.
Cast vinyl films are more conformable than calendered vinyl films, which make them a better choice for applications over rivets and corrugations.
Cast vinyl films are produced at much slower speeds and in much smaller batches than calendered vinyl film. While this adds to its cost, cast vinyl films can be produced in various colors, in production runs as small as 3,000 sq. ft. 

 Final Vinyl Words

Characteristics of the casting process:

1. The ‘casting sheet’, not the film itself, is pulled through the machine. This eliminates mechanical stress (shrinkage) of the film later in its life cycle.

2. It is relatively easy to change color during production: this makes color matching in small batches possible.

3. The temperature at which the cast vinyl film is exposed during production is relatively low. This results in better performance of pigments and UV absorbers once the film is in the field.

4. Cast vinyl films can be made very thin: this is an advantage when applied over textured, corrugated and riveted surfaces, to which cast films can better conform to.

5. No ‘fillers’ are substituted for pigments, therefore creating good opacity.
6. Cast vinyl film’s natural stretch promotes tear resistance.

RELATED ARTICLES
Pressure Sensitives 101 Made Easier
A High Tack Solution for Problem Graphics
Problems Transferring Graphics?
Taking Marketing to the Streets


 CLICK HERE FOR HINGST SIGN POST ARTICLES IN PDF FORMAT

Vinyl Application Videos

Squeegee Technique. Nothing is more basic in vinyl application than the squeegee. But some squeegees work better than others. And there are right ways and wrong ways to use this simple tool. This video clip reviews squeegee selection, squeegee care and squeegee technique. Click to Link

Wet Applications. Dry applications are typically recommended for most vinyl applications. For those exceptions to the rule, this instructional video explains the right way to perform a wet application. Click to Link

Application of Window Graphics. Installing vinyl graphics on glass can be challenging, because the adhesive aggressively grabs onto this high energy surface. Repositioning graphics on window is generally difficult, if not impossible. This instructional video explains how to dry apply window graphics right the first time. It also describes the necessary steps required for surface preparation. Click to Link

Transferring Frosted Window Graphics Films.  Because frosted window films are highly textured, transferring cut vinyl graphics can be problematic. This video provides direction in selection of the right application tape and how to apply these films quickly, easily and without problems. Click to Link

3-Step Surface Prep. This instructional video describes how to properly clean the surface of a vehicle before applying pressure sensitive vinyl graphics to a trailer or doing a full wrap of a car or van. This three step surface prep involves detergent washing, solvent cleaning and a final wipe down with IPA. Click to Link


Vinyl Application Over Rivets. Applying vinyl graphics on vehicle surfaces with rivets is challenging for most sign makers. Vinyl failures to these surfaces are all too common. This video demonstrates some tips and procedures, used by professional decal installers, which will make these demanding applications easier and more trouble-free.  Click to Link

Vinyl Application to Corrugations. Learn how to apply vinyl graphics to corrugations in a relaxed state. Forcing films into the valleys of corrugations puts too much mechanical stress on the film. Sooner or later, the vinyl will lift or tent in valleys. Click to Link

Applying Air Egress Vinyls. Vinyl films with air egress release liners have almost eliminated bubbles and wrinkles from applied graphics. Air egress release liners with their highly textured surface structure are problematic. Not much will stick to these liners other than the vinyl film. At RTape our best premask solution for air egress liners is a special Conform® tape called 4761RLA. Click to Link


About Jim Hingst: After fourteen years as Business Development Manager at RTape, Jim Hingst retired. He was involved in many facets of the company’s business, including marketing, sales, product development and technical service.

Hingst began his career 42 years ago in the graphic arts field creating and producing advertising and promotional materials for a large test equipment manufacturer.  Working for offset printers, large format screen printers, vinyl film manufacturers, and application tape companies, his experience included estimating, production planning, purchasing and production art, as well as sales and marketing. In his capacity as a salesman, Hingst was recognized with numerous sales achievement awards.

Drawing on his experience in production and as graphics installation subcontractor, Hingst provided the industry with practical advice, publishing more than 150 articles for  publications, such as  Signs Canada, SignCraft,  Signs of the Times, Screen Printing, Sign and Digital Graphics and  Sign Builder Illustrated. He also posted more than 325 stories on his blog (hingstssignpost.blogspot.com). In 2007 Hingst’s book, Vinyl Sign Techniques, was published.  Vinyl Sign Techniques is available at sign supply distributors and at Amazon. 

Slides of Jim's Artwork

© 2016 Jim Hingst
at

1 comment: