Shrink Sleeves Production in a Narrow Web Press

Flexible packaging is a broad category that includes many different types of packages such as pouches, bags, wrap labels, blister packs, shrink sleeves, etc.

In the last years, the production of shrink sleeves in narrow web presses has experienced a considerable growth. For this year it is expected a 7-8% growth. According to a survey of the Label Printing Industries of America there will be an increase of about 20% next year in the United States. So, obviously this is an interesting market for narrow web printers.

How is a shrink sleeve produced? The shrink sleeve production involves two manufacturing processes. First of all, there is the printing process where a film is printed on a press from roll to roll. Then there is the converting process where the final sleeve is formed in a separate machine.

Regarding the printing process, the press must have the following features, amongst others, in order to achieve a good result:

• Tension control: The most common material used in shrink sleeve production is PVC and although it is more stable than other filmic materials we have to have a good control over the printing register and the printing length. The best way to do it is with servo drives on each printing and pacing unit.
  
• Material treatment: In order to have a good ink adhesion on the film it is strongly recommended to include a corona treatment unit. Normally the sleeves are printed on the backing side and during the labelling process, when the sleeve is applied to the bottle, scratches could appear in case the ink is not adhered onto the substrate.
  
• UV curing system: A stepless power control is highly recommended in order to minimise the heat produced by infrared radiation during the UV curing process.
  
• Chill rollers: Each printing unit must have a water-chilled roller to maintain a low film temperature when the material passes through the UV lamp. It is recommended that chill rollers are servo driven to avoid web tension problems.