EASTMAN - Afera

EASTMAN 

A new generation of hotmelt tape formulations, 

using blends of SIBS and SBS block copolymers 

and new hydrocarbon tackifying resins 

3 rd Afera Technical Conference 

5-7 April, 2006 

Chrétien Donker, Wim Stevels, Jos Ooms, 

Eastman Chemical Middelburg BV

Introduction 


� World wide isoprene monomer shortage results 

in reduced availability of SIS block copolymers 

for hot melt PSA formulations 

� KRATON Polymers introduced SIBS as an 

alternative block copolymer with lower isoprene 

content to the HMPSA market 

� Specially designed aromatic modified C5 resins 

are necessary to tackify SIBS


How to cope with SIS shortage? 

� Use SBS as block copolymer in the formulation, although 

processability and options for tackification limit the formulation 

window for HMPSA 

� Blends of SIS and SBS are used with variable results 

� With the new SIBS, more blends are now possible: 

- SIBS with SIS 

- SIBS and SBS 

� Using blends of SIBS and SBS would reduce dependency 

on isoprene monomers


Block copolymer blends 

� SIS and SBS block copolymers are known 

to have limited compatibility 

� SIBS is compatible with both SIS and SBS 

� SIBS/SBS blends need specifically designed 

tackifying resins to give optimum HMPSA 

performance



G " ( ) 

[Pa] 

G ' ( ) 

[Pa] 

10 9 

10 8 

10 7 

10 6 

10 5 

10 4 

10 3 

10 2 

SIS/SBS blend 

RRA50011, D-1161_D1152 25_75 

-120.0 -100.0 -80.0 -60.0 -40.0 -20.0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 160.0 180.0 200.0 

Temp [°C] 

10 1 

10 0 

10 -1 

10 -2 

tan_delta ( ) 

[ ]



G " ( ) 

[Pa] 

G ' ( ) 

[Pa] 

10 9 

10 8 

10 7 

10 6 

10 5 

10 4 

10 3 

10 2 

SIBS/SBS SIBS_SBS blend 

-120.0 -94.0 -68.0 -42.0 -16.0 10.0 36.0 62.0 88.0 114.0 140.0 

T em p [°C] 

10 1 

10 0 

10 -1 

10 -2 

tan_delta ( 

[ ] 

)

SIBS/SBS blends 


� A full factorial statistical design was carried out, 

using Kraton's newly developed SIBS and a 

relevant SBS block copolymer 

� Piccotac 7590-N hydrocarbon resin was designed 

to give the correct compatibility in SIBS/SBS 

blends 

� It was decided to start with this resin in the 

SIBS/SBS mixing design study



Initial eleven point screening design study: 

SIBS: 100 –50 phr 

SBS: 0 –50 phr 

Piccotac 7590-N: 115 –175 phr 

Oil: 10 –40 phr



� Formulations were mixed in a Z-blade mixer 

� Coated onto 23 micron Mylar polyester 

� Coating weights 20 g/m 2 

� Tapes were tested in a climate room at 23°C 

and 50% relative humidity



Optimum tape performance window: 

Peel adhesion to steel > 10 N/25mm 

Rolling ball tack < 5 cm 

Loop tack to steel > 15 N/25mm 

Shear adhesion to steel 

@ 23°C, 2.5 kg > 10,000 mins 

@ 40°C, 2.5 kg > 300 mins 

@ 70°C, 0.5 kg > 300 mins 

SAFT, 0.5 kg > 80 °C

B: Resin 

A: Oil 


SIBS/SBS blends, first design



Second eleven point screening design study: 

� SIBS: 75 –0 phr 

� SBS: 25 –100 phr 

� Piccotac 7590-N: 100 –145 phr 

� Oil: 0 –35 phr


SIBS/SBS blends, second design 

25 % SBS



30 % SBS



40 % SBS



50 % SBS



60 % SBS



70 % SBS



75 % SBS



80 % SBS



90 % SBS



100 % SBS


SIBS/SBS blends, optimized formulation 

� The full factorial statistical design suggested 

an optimal formulation to have 

- 125 phr of resin 

- 25 phr of oil 

�SIBS/SBS ratio varied between 0 and 100 % 

�Piccotac 7590-N showed excellent compatibility and 

performance in SIBS/SBS block copolymer blends


SIBS/SBS blends, optimized formulation 

35 

30 

25 

20 

15 

10 

5 

0 

100/0 30/70 50/50 70/30 0/100 

SIBS/SBS ratio 

Peel adhesion 

Shear adhesion at 

40°C, 2.5kg /10 

rolling ball tack 

Loop tack


SIBS/SBS blends, selected resins 

Resin 

Piccotac 

7590-N 

Piccotac 

8090-E 

Piccotac 

6095-E 

Spt 

°C 

90 

92 

97 

Mn 

1000 

1100 

850 

Molecular weight 

Mw 

1700 

2200 

1900 

Mz 

2500 

4200 

4000 

MMAP 

°C 

60 

65 

40 

DACP 

°C 

20 

22 

-10


SIBS/SBS blends, selected formulations 

Formulation 1 2 3 

SIBS 50 50 50 

SBS 50 50 50 

Piccotac 7590-N 125 --- --- 

Piccotac 8090-E --- 125 --- 

Piccotac 6095-E --- --- 125 

Oil 25 25 25 

Antioxidant 2 2 2



30 

25 

20 

15 

10 

5 

0 

Initial results 

Form.1 Form. 2 Form. 3 

Peel adhesion 


70°C,500g /10 

Loop tack 

Rolling ball tack



40 

35 

30 

25 

20 

15 

10 

5 

0 

Aged* results 

Form.1 Form. 2 Form. 3 

Peel adhesion 


70°C,500g /10 

Loop tack 

Rolling ball tack 

*Ageing 14 days @ 40°C


SIBS/SBS blends, mixed in an extruder 

� Piccotac 7590-N and Piccotac 8090-E were 

also blended in SIBS/SBS formulations using 

a laboratory twin-screw extruder 

� Piccotac 7590-N gave the same overall good 

performance as when using a Z-blade mixer 

� Piccotac 8090-E started to give unacceptable 

high rolling ball tack values when blending 

more than 30 phr SBS into the formulation

Conclusions 


� Blends of SIBS and SBS can be used to prepare 

good performing HMPSA formulations, provided the 

right type of hydrocarbon resin is selected 

� A good starting formulation using a 50/50 blend of 

SIBS and SBS contains 125 phr of resin and 25 phr 

of oil. 

� Piccotac 7590-N hydrocarbon resin performed best 

in the above mentioned formulation 

� The processability of the SIBS/SBS concept should 

be elaborated in working practice


Thank you for your attention! 

A special thanks goes to 

- Michaela Hofbauer 

- Wim Stevels 

- Jos Ooms 

Without their help this presentation would not have been possible 

Eastman Chemical Middelburg BV

EASTMAN - Afera

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