Pressure Sensitive Adhesive – Release Liner Interactions in the Label Industry Ingrid Brase and Melanie Lack AWA Global Release Liner Conference, 31 March – 1 Apr 2011

Agenda Introduction Experimental Design Results Summary and Conclusions

Introduction Multiple factors influence the choice of both adhesive and release liner End user requirements Converting, die cutting Printing, dispensing, application Adhesive characteristics Liner characteristics Components are impacted by one another Overall objective is to deliver a label that end user can dispense efficiently

Objectives of the study: Study the interaction of various release liners with different adhesives 5 different commonly used rubber based PSA’s for labels General purpose Freezer grade No –Label look (clear) Alkali wash-off Removable Release liners: Paper and film with various release profiles Easy release, glassine Medium Release, glassine Tight Release, glassine Easy, label standard, glassine PET, 50 μm, easy release

The Adhesives: Performance data All values in N/25mm

Liners: Performance Data All silicones were thermally cured, Pt catalyzed

Sample Preparation Adhesive Coatweight, 20 gsm Samples prepared All adhesives to all paper liners PET liner: alkali wash-off PET liner: no-label look Samples aged for 2 weeks in controlled climate chamber Release force evaluated Low speed, 300 mm/min High speed, 80 m/ min

Observations: low speed release Low speed release simulates manual dispensing Increased force needed for tighter release Clear distinction of release forces based on liner type for GP, freezer and no-label look Release force for alkali wash-off and removable somewhat independent of liner type Highest force needed for GP from tight release

Observations : high speed High speed release simulates machine dispensing See expected patterns for release values: low for easy, medium= medium and high for tight Highest release force needed for removable, all liner types More release differentiation for liners Alkali wash-off shows least force needed for removal

Summary of the data

Conclusions Release behavior varies by speed In general need less release force at higher speed Supports necessity of understanding end user requirements How label will be dispensed is critical Changes in adhesive design have dramatic effects on release forces Alkali wash-off designed for automated lines (high speed) Cannot always conclude release at high speed will take less force Removable needs higher force at high speed (softer?)

SUMMARY AND FUTURE WORK When designing a new label, composition of liner and adhesive both need to be considered based on dispensing and end use Future work: Evaluate impact of adhesive rheology versus release Evaluate different types of silicones, i.e UV cure

Thank you! Acknowledgements: Markus Moeller Monika Veit Mondi – release liners