Adhesion Performance of UV-crosslinked SBS-based PSA

: Effects of SIS contents

2005 Adhesion Conference on Adhesion

Dong-Hyuk Lim1, Hyun-Sung Do1, Hyun-Joong Kim1, Goan-Hee Yoon2

1Lab. of Adhesion & Bio-Composites, Major in Environmental Materials Science,Seoul National University, Seoul 151-921, Korea

2Vixxol, 220-10, Anyang-7 dong, Manan-gu, Anyang-shi, Kyonggi-do, Korea

hjokim@snu.ac.kr / www.adhesion.org

Lab. of Adhesion & Bio-Composites

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Introduction

PSA

Solution-borne

Emulsion (Water-borne)

Hot melt (SIS/SBS)

Irradiation (UV) UV-polymerizableUV-crosslinkable

Classification of PSA manufacture

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Introduction

UV-curing

CoatingWind-up

PSA

Overall process

Compositions1. Oligomer + Monomer + Tackifier + Photoinitiator System2. Block copolymer + Monomer + Photoinitiator System3. Rubber System, Acrylic Hot Melt System

UV-curable Pressure Sensitive Adhesive

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Introduction

SBS based PSA

High solubility parameterHarder polymersMore difficult to tackifyHigh entanglementGood heat resistance

SBS/SIS based PSA

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Introduction

polybutadiene polystyrenepolystyrene

Block copolymer based UV curing system

SBS

RSH (thiol)

UV

Semi-Interpenetrated Network

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Purpose of this study

SBS block copolymer

SIS block copolymer

Thiol-ene polymerization

Adhesion Adhesion Performance of Performance of

UVUV--crosslinkable crosslinkable hotmelt PSAhotmelt PSA

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Experimental

SIS : Vector 4111 (Exxonmobil)

SBS : D KX-405-CP (Kraton)

Photoinitiator : Micure BK-6 (2,2-dimethoxy-2-phenyl acetonphenone)

from Miwon Commercial Co.

Photocrosslinker : TRIS (trimetylolpropane mercaptopropionate) Aldrich

CHCH2 CH2 CH

CH

CH2

CH2 CH CH CH2 CH2 CH

n nmx

Materials

Chemical structure of UV curable SBS with vinyl pendant group

C CH2 O C CH2CH2SH

O

CH2 O C CH2CH2SH

O

CH2 O C

O

CH2CH2SH

CH3CH2

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Experimental

2PI1TRISOilTackifierSBSSIS

94.520501515IB3

94.520507.522.5IB4

94.5205022.57.5IB2

94.52050300IB1

1. TRIS : Photocrosslinker TRIS (trimetylolpropane mercaptopropionate)

2. PI : Photoinitiator Micure BK-6 (2,2-dimethoxy-2-phenyl acetonphenone)

UV-crosslinkable hotmelt PSA composition

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Experimental

Film Casting

UV irradiation

Automatic applicator

No. 22 bar

UV dose : 0, 200, 600, 1000, 14001800 mJ/cm2

UV lamp : high-pressure mercurylamp (100W/cm2, mainwavelength : 365nm)

applicator

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Experimental

FTIR-ATR

Equipment : Nicolet Magna550 Series II

Resolution : 8 cm-1

× 100W24W0

Gel contents (%) =

W24 : weight after dipping for 24 hrsW0 : weight before dipping

TolueneFilm

Gel contents

UVUV -- cured filmcured film

Pressure platePressure plate

Horizontal ATR crystal

UVUV -- cured filmcured film-Coating

Pressure plate

Infrared beam

45o

Substrate

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Experimental

Force

Bonding process

Debondingprocess

Time

Debondingforce

Bondingforce

Probe Tack

Operationregion

Start upregion

Distance PeeledPe

el S

tren

gth

Peel Strength5mm stainless steel cylinderContact force : 100g Dwell time : 1 sec.Separation rate : 60mm/min

Peeling angle : 180ºSeparation rate : 300mm/min

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Experimental

ConstantLoad

ConstantLoad

SUSSUS

PSASpecimen

Oven

Shear Failure

Temp.Checked

Shear Adhesion Failure Temperature (SAFT)

Constant load : 1kgHeating rate : 0.4 ℃/min

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Results and Discussion

Characteristic peak of 910.8 cm-1, 964.7 cm-1

Sites of Chemical Reaction

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Results and Discussion

UV dose : 0, 200, 1000, 2200 mJ/cm2

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

Abso

rban

ce

900 950 1000 Wavenumbers (cm-1)

964.7 cm-1

910.8 cm-1

SBS+Photoinitiator+TRIS

Only SBS

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

0.75

0.80

0.85

0.90

0.95

1.00

Abs

orba

nce

900 950 1000 Wavenumbers (cm-1)

964.7 cm-1

910.8 cm-1

Efficiency of UV curing by thiol-ene polymerization

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Results and Discussion

0 400 800 1200 1600 2000 2400

0

20

40

60

80

100

Gel

con

tent

(%)

UV dose (mJ/cm2)

SBS SBS+PI SBS+PI+TRIS

Gel content

Gel contents of UV crosslinked SBS

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Results and Discussion

CH2 CH CH2 CH

CHCH2CHCH2R

CH2 CH CH2 CH

CHCH2CHCH2R

CH2 CH CH2 CH

CHCH2

CH CH2 CH

CHCH2

CH2R

CH2 CH

CH

CH2

CH2

CH

CHCH2R

Photoinitiator

.

.

. .

SBS & Photoinitiator SBS & Photoinitiator & Photocrosslinker

hv

Intra reactionInter reaction

Mechanism of Thiol-ene polymerization

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Probe tack

SBS+SIS+PI SBS+SIS+PI+TRIS

Probe tack of SBS/SIS based UV curable PSA

0 400 800 1200 1600 2000

0

200

400

600

800

1000

Prob

e ta

ck (g

f)

UV dose (mJ/cm2)

No TRIS SIS:SBS=0:30 SIS:SBS=7.5:22.5 SIS:SBS=15:15 SIS:SBS=22.5:7.5

0 400 800 1200 1600 2000

0

200

400

600

800

1000

Prob

e ta

ck (g

f)

UV dose (mJ/cm2)

TRIS SIS:SBS=0:30 SIS:SBS=7.5:22.5 SIS:SBS=15:15 SIS:SBS=22.5:7.5

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Peel strength

SBS+SIS+PI SBS+SIS+PI+TRIS

Peel strength of SBS/SIS based UV curable PSA

0 400 800 1200 1600 20000

500

1000

1500

2000

2500

3000

3500

Peel

str

engt

h (g

f)

UV dose (mJ/cm2)

No TRIS SIS:SBS=0:30 SIS:SBS=7.5:22.5 SIS:SBS=15:15 SIS:SBS=22.5:7.5

0 400 800 1200 1600 20000

500

1000

1500

2000

Peel

str

engt

h (g

f)

UV dose (mJ/cm2)

TRIS SIS:SBS=0:30 SIS:SBS=7.5:22.5 SIS:SBS=15:15 SIS:SBS=22.5:7.5

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SAFT (Shear adhesion failure temperature)

SBS+SIS+PI SBS+SIS+PI+TRIS

SAFT of SBS/SIS based UV curable PSA

0 200 400 600 800 1000

20

40

60

80

100

No TRIS SIS:SBS=0:30 SIS:SBS=7.5:22.5 SIS:SBS=15:15 SIS:SBS=22.5:7.5

SAFT

(o C)

UV dose (mJ/cm2)

0 200 400 600 800 1000

20

40

60

80

100

SIS:SBS=0:30 SIS:SBS=7.5:22.5 SIS:SBS=15:15 SIS:SBS=22.5:7.5

SAFT

(o C)

UV dose (mJ/cm2)

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Failure mode of holding power (40oC)

SBS+SIS+PI+TRIS

SBS+SIS+PI

Adhesive failure

Cohesive failure

0 200 600 1000 1400

0 200 600 1000 1400UV dose (mJ/cm2)

UV dose (mJ/cm2)

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Conclusion

Pro

be ta

ck

Pee

l stre

ngth

SA

FT

UV dose UV dose

UV dose

Only SBS

Adhesion performance of SBS/SIS based UV curable PSA

Not detected

Only SBSOnly SBS

SIS content

SIS contentSIS content