Part II: 접착/점착의 화학과 응용 점착제의 물성

1. 점착제의 물성과 상용성 Pressure Sensitive Adhesives

Pressure Sensitive Adhesives = Elastomer + Resin - Acrylic based - Rosins - Silicone based - Terpenes - Block Copolymers - Synthetic Resins - Others (C-5, C-9, and (C-5)2)  to modify the practical performances (tack, peel strength, and shear creep resistance )

Adhesives & Pressure Sensitive Adhesives <Contact Process> <Curing> <Fracture Process> Evaporation Cooling Reactive Liquid Adhesives PSAs Solid Semi-Solid Viscoelastic materials Semi-Solid

Structure of PSAs PSA Silicon Paper Coating Substrate Backing

3 Performance of Pressure Sensitive Adhesives Adhesion Tack Cohesion

The Rheological Bridge Molecular Structure Rheology (Viscoelastic Properties) Processability & Product Performance  MW & MWD  Chain Branching & Cross-Linking  Interaction of Filler With Matrix Polymer  Single or Multi-Phase Structure As a Function of :  Strain Rate  Strain Amplitude  Temperature

Dynamic Analysis for Viscoelasticity by DMTA Solids Theromosets Thermoplastics Elastomers Composites BENDING TORSION TENSION COMPRESSION

Dynamic Mechanical Measurements G = ’max  max Elastic Modulus (Storage Modulus) Represents How Much Energy A Materials Stores Through Elasticity. G =  max  max Viscous Modulus (Loss Modulus) Indicates A Material’s Ability To Dissipate Energy - Often In the Form of Heat tan  = G’ G Loss Factor Compares (Damping Factor) The Relative Importance of Viscous and Elastic Behavior for A Material.

Typical Characteristics of Viscoelastic Spectrum Increasing MW Increasing Crystalline 104 1010 108 106 Storage Modulus (G) Temperature (oC) Cross-linked Amorphous Crystalline Tg

Storage Modulus and Peel Strength for Rubber-based PSAs (with Tackfier Resin) Temperature (℃) Storage Modulus (G', dyne/cm2) -40 40 80 120 160 T-0 T-1 T-2 T-3 T-4 7 8 5 6 Log G' (70℃) Peel strength (kgf/cm) 1.0 0.1 0.01

Storage Modulus and Peel Strength for Acrylic PSAs (with Tackifier Resin) Log G' (70℃) Peel strength (kgf/cm) 0.1 5 7 6 1.0 0.3 T-0 T-1 T-2 8 40 80 120 160 Temperature (℃) Log G’, dyne/cm2

Resin Formulation and PSA Performance for Natural-based PSAs NR (100 parts) + Terpene Resins (60 parts) 100 80 20 60 40 Ball tack (ball number) 18 12 10 8 6 4 16 Ratio (Part, %) Ball tack Peel strength Holding Power Β-Pinene Dipentene Average molecular weight 300 400 500 600 700 800 900 1000 Peel Strength (gf/25mm) 0.7 0.6 0.5 0.4 0.3 0.2 0.1 Holding Power (mm) 1100 1200 1400 1500 14 1300 Average Molecular Weight

Role of Tackifier Resin Rubber based PSAs Type Rosin Hydrogenated Rosin Ester Terpene Terpene-Phenol Aliphatic Hydrocarbon Aromatic Hydrocarbon Adhesion Tack Cohesion Miscibility Aging Resistance Price 1 4 1 3 1 4 2 4 2 3 3 2 3 4 3 4 3 2 4 3 4 3 2 1 3 3 4 1 3 3 2 1 3 3 3 4 1: 가장 좋다(가격이 싸다), 2: 좋다 (싸다), 3: 약간 나쁘다(약간 고가), 4: 나쁘다(고가)

Elastomer와 점착부여수지의 상용범위 SP값 8.0 8.5 9.0 Elastomer HR NR BR SBR 아크릴계 NBR (PP, PE) SIS SBS 터펜수지, C5계석유수지, 안전수첨석유수지 α-피넨수지 방향족변성터펜수지, 수첨터펜수지(방향족변성함유 C5·C9공중합계석유수지 C9계석유수지 터펜페놀수지, 로진에스테르수지 쿠마론인덴수지, 스티렌수지 EVA 점착부여수지

점착부여제의 특성비교 (천연고무계점착제) 4: 가장 좋음(가장 저가) 3: 좋음 (저가) 2: 약간 나쁨(약간 고가) 1:나쁨(고가) www.adhesion.org

Adhesion / Cohesion Requirements of PSA products Permanent Labels Packaging Tape A D H E S I O N Decorative films Removable Labels Protective Films COHESION

Performance of PSA and Characteristics of Resin M.W. Acid Value TACK ADHESION COHESION HEAT RESISTANCE Tg

Cohesion (Holding Power) Shear Creep Resistance Test of PSA Performance Aluminum PET(25m) V PSA (20m) Substrate: Aluminum Cross Head Speed: 10-5 ~ 101 (cm/sec) Temperature: 20 - 110°C for 24 h Adhesion (Peel Strength) T (°C) 2.5cm Temp.: 30, 40, 50, and 70(°C) Aluminum o Cohesion (Holding Power) Shear Creep Resistance Probe Tack Test contact time: 3 seconds contact pressure: 100gf temp.: 20 - 70 (°C) rate of separation(mm/min) : 2.5, 5, 30, 120, and 600  force maximum (max)  fracture energy (W=(1/A) Fv dt))

Typical Type of Phase Diagrams UCST LCST 1 phase 2 phases 1 phase 2 phases LCST: UCST: Lower Critical Solution Temperature Upper Critical Solution Temperature T (°C)

Master Curves of Peel Strength against VaT S. Hayashi, H. J. Kim, and H. Mizumachi, J. Adhesion Society of Japan, 31(10), 407(1995) Master Curves of Peel Strength against VaT for acrylic PSAs (reduced to 28°C)

Master Curves of Peel Strength against VaT S. Hayashi, H. J. Kim, and H. Mizumachi, J. Adhesion Society of Japan, 31(10), 407(1995) Master Curves of Peel Strength against VaT for acrylic PSAs (Miscible) system

Master Curves of Peel Strength against VaT S. Hayashi, H. J. Kim, and H. Mizumachi, J. Adhesion Society of Japan, 31(10), 407(1995) Master Curves of Peel Strength against VaT for acrylic PSAs (Immcible) system

H. J. Kim and H. Mizumachi, J. Adhesion, 49, 113 (1995) Phase diagram, Tg-composition curve and master curve of probe tack of acrylic PSAs. T E M P R A U

H. J. Kim and H. Mizumachi, J. Adhesion, 49, 113 (1995) Phase diagram, Tg-composition curve and master curve of probe tack of acrylic PSAs. T E M P R A U

Master curves of shear creep resistance H. J. Kim and H. Mizumachi, J. Appl. Polym. Sci., 58, 1891 (1995) Master curves of shear creep resistance of acrylic PSAs miscible and immiscible systems.

Dynamic storage modulus and loss tangent H. J. Kim and H. Mizumachi, J. Appl. Polym. Sci., 58, 1891 (1995) Dynamic storage modulus and loss tangent vs. temperature of acrylic PSAs (miscible and immiscible).

Plot of storage modulus (G’) and holding time (tb) H. J. Kim and H. Mizumachi, J. Appl. Polym. Sci., 58, 1891 (1995) Plot of storage modulus (G’) and holding time (tb) of acrylic PSAs

Schematic Representation of PSA Performance H. J. Kim and H. Mizumachi, J. Adhesion, 49, 113 (1995) Schematic Representation of PSA Performance (PROBE TACK) for Miscible Blends Increasing Tackifier (Increasing Tg) P R O B E T A C K Polymer Log V Experimental Velocity

Schematic Representation of PSA Performance H. J. Kim and H. Mizumachi, J. Adhesion, 49, 113 (1995) Schematic Representation of PSA Performance (PROBE TACK) for Immiscible Blends Increasing Tackiifer (Constant Tg) Polymer P R O B E T A C K Log V Experimental Velocity

Schematic Representation of PSA Performance H. J. Kim and H. Mizumachi, J. Adhesion, 49, 113 (1995) Schematic Representation of PSA Performance (PEEL STRENGTH) for Miscible Blends P E L S T R N G H Increasing Tackifier (Increasing Tg) TEMPERATURE (Cohesive Failure) (Adhesive Failure) & log V

Schematic Representation of PSA Performance (HOLDING POWER) for Blends H. J. Kim and H. Mizumachi, J. Adhesion, 49, 113 (1995) Schematic Representation of PSA Performance (HOLDING POWER) for Blends For Miscible Blends For Immiscible Blends Increasing Tackiifer (Increasing Tg) Increasing Tackiifer (Increasing Tg) o (g/cm2) aTtb(seconds) aTtb(seconds)