What FMCG Companies Must Know If Still Using Blown PVC
PVC is the most widely used shrink film in India, manufactured in bulk, and so it is readily available. It works with almost all kinds of shrink tunnels and container materials and is most versatile. But, since PVC is carcinogenic nature, it is not recommended and avoided by many global companies. However, it is also the most easily recyclable shrink film. If properly collected and disposed of, it creates high value for scrap recycling companies.
CAST or Calendared PVC is of superior quality. However, many of its cheaper versions such as Blown PVC is available and widely used, often replaced with CAST PVC. Both these PVC’s have specific uses.
How are Cast and Blown PVC Different and What Makes Cast PVC Better?
Blown PVC films are manufactured by extruding resin vertically through a circular die and blowing air in the center of the film bubble. The air drives the bubble upward and slowly cools the material. Nip rollers flatten the material into a tube that is reeled, and its sides trimmed to create sheet films. Blown films get stretched in a hot water chamber during the manufacturing process.
Cast films are made by extruding melted resin horizontally through a flat die to create a sheet of material pinned to a highly polished chilled roller. Additional chilled rollers quickly cool the film prior to trimming and rolling. Cast films are minimally pre-stretched allowing for improved depth of drawing for thermoforming operations. Typically, cast films have low thickness variation due to an even distribution of PVC resin.
When to Use Cast Film Vs Blown Film?
Blown PVC has low, uneven shrinkage. It may come with process scratch lines and is difficult to print in multicolor.
Recommended Use:
- It is better to use Blown PVC in outer plain packing, or
- When the print design has only two to three colours, or
- Where product branding is not critical
- If your PVC sleeves are shrinking at room temperature in transit and storage regularly, use the grade of Cast PVC with High Dimensional Stability
Key Differences
Property | Blown PVC | CAST PVC |
Film Clarity | Low gloss and Hazy | High Gloss, better visibility |
Thickness variation | More than +/- 10 Micron | +/- 5% (around 2 micron) |
Flatness | Ribs on the film | Mostly Flat film |
Storage and Transportation | A major challenge due to high natural shrinkage | Better resistance to heat. So easier to handle. |
Shrinkage | Approx. 45% | Approx. 58% |
Printability | Lot of misregistration issues | Flat film, allows perfect registration quality |
Surface Finish | Heavy machines process scratch lines on the surface | Minimal machine process lines |
Cost | Cheap | Higher than CAST PVC |
Other Factors to Consider
Since Blown PVC is cheaper, it can be used for outer shrink wrap. However, even then there is a catch. The heavy scratch on the film’s surface and the hazy quality of the film makes the product look old/reused.
Also for outer packing, as per current PWM laws, most consumers are required to use 50 mics and above thickness film for outer packing. In blown PVC, there is a high risk of legal tangles as the film has high gauge variation which is up to+/-10 micron. If a 50-micron film is used and has variation in the lower side then it will go below 50 microns at some points.
Closing Thoughts
Even though Blown PVC is attractively priced, its results do not outweigh the price. Lower print and shrinkage quality affects the brand. A lot many companies in the industry value price of sleeves more than their brand, which I feel must change. When we make our packaging world-class and at par in the industry, only then we can command a better profit. Hence, such a thought process requires change and a more detailed understanding of how packaging affects profits. I believe it’s important for all FMCG companies to understand the value of the brand and good-looking packaging. I am taking it as a personal mission to make Indian packaging world-class.
To get an expert opinion on this matter, feel free to reach out to me. You can book a discovery call with me at www.chetan-jain.com.