1. New Hot Melt Formulations for Tape and Label Applications
Ingrid Brase & Yuhong Hu
AWA Adhesives Technology Seminar
Chicago
March 2013

2. Pressure Sensitive Adhesives – Key Requirements
Adhesion
Strong enough
to bond/hold
Wet out
Allows adhesive to
flow and penetrate
Balance of the two at a certain time scale
Peel Strength
Shear Resistance
Quick Stick / Tack
Heat Resistance – SAFT, Heated Shear
Release Force from the liner

3. Pressure Sensitive Adhesives – Hot Melt
Hot Melt: Strength
Hot Melt: Weakness
Easy to apply, no drying, no solvents,
environmental friendly
Fast setting for high production speed
Short compression time
Small space needs, immediate use of
product
Easy to store, 100% solids, stable
Aggressive tack, good adhesion on
LSE
Cost effective
Relatively poor aging
especially under UV
Inherently limited by high
temperature (heat sensitivity)
Limited solvent-resistance

4. Hot Melt PSA — Raw Materials
Polymer %
Mw > 10,000
cohesion: inner strength
flexibility, toughness
Tackifier Resin %
Mw < 5,000
adhesive strength, stickiness
determines surface energy
Diluent %
Mw <1000
optimization of flow properties, viscosity
Additives < 5%
protects or modifies properties; antioxidants

5. Properties dependent on:
Hot Melt PSA Raw Materials – Polymers
Long chains molecules comprised of
building blocks known as monomers.
Properties dependent on:
Molecular weight
Molecular weight distribution
Chemistry type
Co-monomer type and ratio
Morphology
Saturation
Polymer Function
Strength
Toughness
Flexibility
Stability
Elongation
Adhesion

6. Hot Melt PSA Raw Materials – Styrenic Block Copolymers
Styrenic Block Copolymers: SIS, SBS, SEBS, SEPS
Anionic polymerization, very narrow Mwt distribution
Physical crosslinking by phase separated mid-block and end-block
SBS
SIS
SEBS
SEPS
Thermal Stability
Fair
Poor
Excellent
Mid block Tg
-85
-60
-55
Solubility Parameter
8.35
8.15
7.75
7.65

7. Properties dependent on:
Hot Melt PSA Raw Materials – Tackifiers
High glass transition temperature
Low molecular weight amorphous polymers
Compatible with the base polymer
Properties dependent on:
Tackifier Function
Raise Tg of polymer
Reduce entanglements
Promote wet-out
Reduce viscosity
Tack
Adhesion
Chemistry Type - Feed Stock Source
Viscosity
Softening Point (Ring & Ball) (~ Tg °c)
Molecular Weight
Acid Number
Density
Color (Gardner)
Compatibility to polymer phase

8. Hot Melt PSA Raw Materials – Tackifiers
Hydrocarbon base (oil & gas)
Acyclic and cyclic C5 & C9
Dicyclopentadiene
Features
Used extensively in all hot melt adhesives
Good adhesion to both stiff and more flexible substrates
Low odor and color (hydrogenated HC)
Key tackifier in some regions for products used in the hygiene market
Wide formulating latitude

9. Hot Melt PSA Raw Materials – Tackifiers
Natural Sources (trees & paper industry)
Rosin Esters - derived from pine tree resins
- gum rosin based or tall oil based
Terpene and derivatives
- from orange peel/pine extracts
Features
Used extensively in PSA and packaging applications
Excellent compatibility with both SIS and SBS
Enhance adhesion to polar substrates
Range of softening points available leading to formulating latitude

10. Hot Melt Physical Properties Testing
Bulk Properties:
Brookfield viscosity
Color
Softening point
Viscosity and color stability
Rheology
Tensile
Density

11. Hot Melt PSA — Typical Applications
Labels
Graphics
Tapes
HMPSA
Hygienic
Medical
Automotive

12. Hot Melt PSA for Labels General Requirements
Quick stick, good wet-out on various substrates
Good die-cutting and matrix stripping
No edge lifting
Humidity resistance
Good adhesion at both ambient and cold temperatures **
Clarity **
Re-positionable or removable **
** for specific applications

13. Hot Melt PSA for Labels Application Slot die, roll coat
Line speed, 500 – 1000 ft/min
Typical coat weight
0.8 to 1.2 mil
Property and Application testing
Peel, tack, shear on SS, corrugated, LDPE, HDPE, etc.
95% RH and 95ºF aging test
Staining test
Stripping and die-cutting
Release force test

14. Hot Melt PSA for Labels — Examples
Applications
Properties
General Purpose Paper labels
Balance tack, peel, shear, permanent bond
Clear bottle labels
Light color, clear/no look label
Packing slips
Aggressive tack, migration resistance
Fruit labels/ Food labels
Food Contact, FDA compliance
Tire labels
High initial tack, good wet out on LSE
Dairy labels/ Freezer labels
Soft, low Tg, broad Tg, adhesion on moist surface
Removable labels
Low adhesion, no build up, no transfer, removable

15. Examples — General Purpose Labels
Considerations
Adhesion / Tack
Removal / Cohesion
Die Cuttability
Staining resistance
Transparency *
Ingredients
% range
Function
SIS or SBS
20-30
Cohesion
Tackifier (C5/C9, Rosin ester…)
45-60
Wetting of surface, increase Tg
Oil
20-25
Surface tack, lower Tg AO
0.5
Thermal stability

16. Expanding Portfolio: Low Temperature Hot Melt PSA
Gap in product line: optimized product for low temp applications
Adhesion and quik stik at low temp
Good release for auto dispensing

17. Low Temp Label Product
Utilize key raw materials to meet criteria

18. Low Temperature HMPSA for Labels: Rheology

19. Release Force Charts Original Adhesive Modified Adhesive
Release force values at 1200 in/min
Original grams/in
Modified grams/in

20. Hot Melt PSA for Tapes General Requirements
Adhesion to hard-to-stick surfaces and various foams
Excellent holding power after aging
Good adhesion at elevated temperatures
Resistance to various environmental conditions
Met skin contact requirement **
** for specific applications

21. Hot Melt PSA for Tapes Application Slot die Line speed 50 – 300 ft/min
Typical coat weight
2 to 5 mil
Property and end-use testing
Ultimate holding power (static shear)
Static shear at 40ºC, 50ºC and 60ºC
S.A.F.T on PET and foil
Adhesion on foam
Aging performance
Peel, tack

22. Hot Melt PSA for Tapes — Examples
Applications
Properties
High shear tape
High cohesion, high S.P.
high S.A.F.T.
Foam tape
Aggressive grab on various types of foam, high S.A.F.T.
Removable tape
No build up, no transfer, removable
Road marking tape
Aggressive tack, good aging performance
Hook & loop/ diaper tape
Good wet out, high cohesion, high shear at body temp, high peel adhesion
Automotive tape
High heat resistance, good aging performance
Medical tape
High MVTR, non-irritating to skin, painless removal, good grab

23. Examples — High Shear Tape
Considerations
High shear
Cohesion
Heat resistance
Adhesion on hard-to- stick substrate
Good grab
Ingredients
% range
Function
SIS or SBS
30-40
Cohesion
Tackifier (C5/C9, Rosin ester…)
40-60
Wetting of surface, increase Tg
End block tackifier
0- 15
Increase shear resistance
Oil
5-20
Surface tack, lower Tg AO
0.5
Thermal stability

24. Creating High SAFT/ High Cohesion HMPSA’s
High SAFT/ High Shear HMPSA’s
Balanced performance: cohesion/ adhesion
Reasonable coating viscosity

25. High SAFT/ High Shear HMPSA: Adhesion profile

26. High SAFT/ High Shear HMPSA: Cohesion Profile
Hours
72oF
120oF
158oF
SAFT, oF

27. High SAFT/Shear HMPSA

28. Summary
HMPSA can be utilized for a wide variety of pressure sensitive applications
Understanding end use and process requirements is key
Skilled formulators can use tools available to meet new and emerging needs

29. Acknowledgements
Bill Chen
Pete Walter
Brad McLeod
Stephen Shepherd

30. THANK YOU! ANY QUESTIONS?