Introduction to Psa Technology
Transcript of Introduction to Psa Technology
©2006 LEVERA Pte Ltd
Introduction toIntroduction to
Pressure Sensitive Adhesive Pressure Sensitive Adhesive
Technology Technology
Process Engineering Technical Training Series
CC Lee
Principal Consultant
©2006 LEVERA Pte Ltd
Definition of PSADefinition of PSA(Pressure Sensitive Adhesives)
A special class of adhesive that is:
• Permanently tacky at Room Temperature
• Spontaneously adhere on contact or with little pressure
• Require no activation by water, solvent or heat to form a strong bond
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PSA Polymers Life CyclePSA Polymers Life Cycle
InfancyInfancy
GrowthGrowth
MaturityMaturity
AgeAge
Hot Melts of
• UV radiation cured Acrylic
Emulsions of
• Acrylic copolymers
• SB copolymers
Hot Melts of
• SIS/SBS block
Copolymers
Solvent Solutions of
• Rubber/Resin
• Acrylic
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Common PSA ClassificationCommon PSA Classification
NoneNoneNoneHigh
TemperatureSilicone
EmergingCommonFewFewRubber
EmergingDevelopmentalMost CommonSpecialty
Acrylic
UV Hot MeltHot MeltEmulsionSolvent
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Typical PSA Polymer Performance Typical PSA Polymer Performance
0
10
20
30
40
50
60
70
80
90
100
Heat R
esist
ance
Chem
ical R
esist
ance
UV Res
istan
ceAdh
esive
Clea
rity
Apolar
Adh
esion
Wat
er R
esist
ance
UV Acrylic
EmulsionAcrylic
Hot MeltSBS/SIS
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Common PSA coating methodsCommon PSA coating methods
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Capabilities / Limitations of Common Coating MethodsCapabilities / Limitations of Common Coating Methods
Emulsion, hot melt100-500220-50050,000-125,000Curtain
Emulsion, hot melt, 100% solids
100-300220-700400-
200,000Slot die
Emulsion, hot melt, 100% solids
300-700515-750.400-
500,000. Extrusion die
Solution, emulsion100-70022-5015-1500Gravure
Solution, emulsion100-700525-250300-50,000Reverse roll
Solution, emulsion,100% solids
100-4001025-7504,000-50,000
Knife over roll
Solution, emulsion100-1501015-100100-1,000Wire rod
Type of AdhesivesCommonly Used
Coating Speed,m/min
CoatingAccuracy,
+/- %
Coating Weight,gm/m 2
Viscosity,> cps
Coating Method
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Variation of Adhesion with Coat WeightVariation of Adhesion with Coat Weight
0
2
4
6
8
10
12
2 6 10 14 18 22 26 30
Adhesive Coat Weight (gsm)
Adh
esio
n (N
/25m
m)
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Typical Emulsion PSA Materials Typical Emulsion PSA Materials
Manufacturing ProcessManufacturing Process
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Emulsion PSA Label Manufacturing Process
5 Rollers Silicone Coater
Vario Gravure Adhesive Coater
Laminator
Corona Discharge
Adhesive OvenUV Radiation
Facestock Unwind
Product Rewind
Liner Unwind
Face-stock
Adhesive
Silicone Release
Liner
Corona Discharge
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Emulsion Emulsion VarioVario Gravure CoaterGravure Coater
Gravure roll
Application roll
Backing roll
Feed box Pressure Range: 0.2 -0.6 bar Above Atmospheric Pressure
Speed Ratio Application roll / Line Speed Ratio Range: 1.1 -1.3
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Reverse Gravue Coat Weight Chart
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9
Speed Ratio
Wet
Coa
t Weigh
t (gs
m) 25
28
30
45
55
65
90
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Relative Effects of Parameters on the Evaporation Time of Relative Effects of Parameters on the Evaporation Time of
Polymer Polymer --Water MixturesWater Mixtures
10.2Other
<0.160-100Water content, %
1.610-30Air speed, l/min
20.220-40Temperature, °C
60.210-90Relative humidity, %
Effect on Evaporation Rate% Range Investigated Parameter
The combination of hot air and infrared radiation are well suited for the accelerated drying of waterborne adhesives and coatings. This is probably the most effective variation in formulation or production to gain a large improvement in speed. The hot air primarily affects the coating surface while the IR radiation, depending on the wavelength can penetrate into the deeper layers of the coating. With the IR method, favored evaporation of water can be achieved through irradiation in the OH band region
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Adhesive Drying Chart
50
60
70
80
90
100
110
120
130
140
150
160
170
60 70 80 90 100 110 120 130 140 150 160 170
Line Speed
Ove
n T
empe
ratu
re o
C10
12
14
16
18
20
21
22
23
24
25
26
27
28
Water Content gsm
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Formulation of Emulsion PSAFormulation of Emulsion PSA
Ammonia
Thickener/
Water
Wetting Agents
Defoamers
Plasticizer
Base
DispersionTackifiers
Mixer
PumpFilter
Storage
Tank
QC:
•Solid Content
•pH
•Viscosity
•Wetting
•Foam
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Ad
hesio
n/T
ack
CohesionLow High
Low
High
Heat
Resistant
Removable
General Purpose
Permanent
High Tack & Adhesion
Cold
Temperature
Classification of Adhesive by Classification of Adhesive by
Common FunctionsCommon Functions
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Quality Control after Coating ProcessQuality Control after Coating Process
Quantitative Criteria:
1. Adhesion
2. Initial Tack
3. Cohesion
4. Coat Weight
Qualitative Criteria:
1. Adhesive Voids
2. Air Bubbles
3. Foreign Particles
4. Clarity