Pressure Sensitive Adhesive Tapes for Sales and Marketing Professionals Tape University Basics May 11, 2009 Testing

All the Common Test Methods You Will Ever Need!

Testing of Pressure Sensitive Adhesives (Tapes) PURPOSE: Quality & Process Control Comparative Testing Performance Characteristics Functional Property Testing Data Sheets

Tape Physical Properties Adhesion Performance Peel Adhesion, Shear Adhesion, Tack (Wet Grab) Tape Constructions Elongation, Tensile Strength, Thickness Application Special Requirements Aging Properties Electrical Properties Solvent Resistance Barrier Properties FDA Requirements Flammability

Achieving The Correct Level of Performance When designing a product, a change in chemistry to impact any one single performance factor has to be balanced with the other two. TACK SHEAR ADHESION Cost must also be considered

Peel Adhesion The force per unit width required to break the bond between a pressure sensitive adhesive tape and the surface to which it has been applied when the tape is peeled back at a controlled angle at a standard rate and condition.

PSTC 101 Comparison of Current Peel Adhesion Test Methods with Harmonized International TM Reference: Jensen, T.B., FEICA European Adhesives Conference, 1999.

Peel Adhesion - 180o/ 90o FORCE FORCE TEST SURFACE ADHESIVE ADHESIVE PSTC - 1 PSTC - 101 ASTM D 1000 ASTM 3330 M TEST SURFACE 180° PEEL ADHESION 90° PEEL ADHESION Measures the force required to remove the tape from a test surface at a given angle, temperature and peel rate

Peel Adhesion Video

Types of Release Modes BACKING COHESIVE FAILURE ADHESIVE FAILURE ADHEREND BACKING ADHESIVE ADHEREND 50% COHESIVE FAILURE Which mode is missing? Reference: Petrie, E.M., Handbook of Adhesives and Sealants, pg. 4, 2000.

Significance of Peel Adhesion Testing WHAT YOU NEED TO KNOW! FORCE Peel adhesion measures bond breaking not bond formation. Peel value is a function of test conditions (contact time, application pressure, temperature, peel rate and peel angle). Surface tension dominates wetting and visco-elastic behavior dominates flow. TEST SURFACE ADHESIVE 180° PEEL ADHESION TEST

Tack The property of a pressure sensitive adhesive that allows it to adhere to a surface under very slight pressure. It is determined by the ability of the adhesive to quickly wet the surface it contacts.

Tack Test Methods Rolling Ball Polyken® Probe Tack Texture Analyzer Loop Tack

Rolling Ball Tack A Stainless Steel ball is released on to a strip of tape. The distance the ball travels is measured: In inches or cm Corresponding quantitative measurement based on the distance it travels TAPE DISTANCE TRAVELED PSTC - 6 ASTM D 3121

Rolling Ball Tack Video

Probe Tack Test A tape sample is lowered to a touch probe and withdrawn. The force to pull away is measured ASTM D 2979 Tack is reported as gm/area and weight of probe for example 500 gm for a 100gm/cm2 probe TAPE PROBE

Probe Tack Video

Loop Tack - PSTC 16 UPPER GRIPS 1 INCH (25 MM) MASKING TAPE LOWER GRIPS TEST FIXTURE ADHESIVE COATED SIDE IN CONTACT WITH SUBSTRATE SUBSTRATE BAR Reference:Test Methods for Pressure Sensitive Adhesive Tapes, 13th Edition, Pg. 68 & 2000.

Significance of Tack Level Testing What You Need To Know! TAPE LOOP TACK ROLLING BALL TACK PROBE TACK Tack is NOT an indicator of adhesion value Tack is a measurement of the initial “stickiness” of the adhesive when it comes into contact with the intended substrate

Shear Sometimes referred to as holding power and/or creep of the adhesive. Evaluate adhesive strength (cohesiveness) and resistance to flow under stress. Adhesive compliance sufficient to conform to surface roughness.

Common Shear Tests Static Shear Adhesion as a Function of Temperature (SAFT)

COMPARISON OF SHEAR TEST METHODS Reference: Muny, R.P., Handbook of Pressure Sensitive Adhesive Technology, Third Edition, Edited by Satas, D., pg. 144 & 1999.

PSTC 107 Comparison of Current Shear Holding Power (Shear Adhesion) Test Methods with Proposed (Third Draft) Harmonized International TM Reference: Jensen, T. B., FEICA European Adhesives Conference, 1999.

Static Shear Test w h L t η Measures the time required for a pre-determined load (weight) to move the tape a given distance across the test panel. One square inch area of contact with a 1000 gm load is standard but may be varied. Results are reported in minutes or hours TEST SURFACE Time to Fall = η w h2 L t

Shear Test Video

Significance of Shear Testing STATIC SHEAR TEST WHAT YOU NEED TO KNOW! Shear is an indicator of the internal strength (cohesiveness) of the adhesive Shear value is a function of test conditions (contact time, application pressure and temperature)

Resistance to Aging Purpose: Determine shelf life Determine functional life time.

Method Expose tape on test panel to test conditions and measure attributes as a function of time.

Aging Devices Oven Cycling Chamber Weathering Chamber User Designed

Shelf Life Hot dry conditions (120-150ºF) for various times. Hot-moist conditions (96% RH & 100º F) for various times. Cycling (hot-cold-hot, dry & moist)

Tape Data Sheet Attributes Properties Physical properties such as peel, shear, tack, tensile, elongation and thickness measured under controlled conditions Storage conditions Broad comments on handling, regulatory issues, and application Peel adhesion, 40 oz/in PSTC-101 Shear, 500 minutes PSTC-107 Tack, 2 mm PSTC-6 Tensile at Break, 20 newtons/10 mm PSTC-131 Elongation at Break, 200% PSTC-131 Thickness, 2.25 mm PSTC-133 Data sheets do not typically contain information about fitness for use The end user usually qualifies the adhesive in the end use Physical properties are determined on controlled and reproducible surfaces such as stainless steel panels Data sheets typically present nominal data and are used as guidelines Are data sheets specifications?

Testing Considerations Test method, conditions and operator govern results Use industry recognized test methods to compare results The test results are only as good as the test method and operator!