Standard Test Method for Pressure-Sensitive Tack of Adhesives Using an Inverted Probe Machine
APP-D2979Clean the stainless steel probe tip with reagent-grade toluene or isopropyl alcohol and a lint-free wipe before every single stroke.
Challenge & Testing Gap
Microscopic contaminants on the probe tip surface and variable contact dwell times generate severe, unrepeatable tack spikes.
The Solution
Incorporate an inverted mechanical probe assembly featuring an automated dwell timer and an high precision micro-load cell.
Mechanics & Specimen Behavior
Primary Mechanics
Vertical compression force application followed by rapid tensile separation of a flat-faced cylindrical probe from an adhesive film.
Specimen Details
Pressure-sensitive adhesive (PSA) films or tapes backed by a rigid carrier ring, resting flat on a horizontal base plate.
Mechanical Ratios & Properties
Standardized 5.0mm diameter cylindrical probe face interacting with a consistent 100 gram-force (0.98 N) compressive load.
Expert Engineering Commentary
Core Problem Identification
Erratic tack force readings triggered by the probe tip entering or exiting the adhesive layer at a micro-skewed angle.
Root Cause Analysis
Failing to clean the probe tip with high-purity solvents between test cycles, leaving microscopic adhesive residue.
Hardware Specific Solutions
Inverted probe tack apparatus featuring a mirror-polished Type 316 stainless steel probe and an electronic contact dwell controller.
Analysis & Calculation Standards
Event & Failure Detection
Precise 1.0-second contact dwell clocking combined with rapid automatic peak tensile force tracking on the up-stroke.
Required Calculations
Maximum Probe Tack Force (expressed in Newtons or grams-force), Peak Separation Force, and Failure Mode (cohesive or adhesive).
Statistical Outputs
Arithmetic mean of peak tack metrics, standard deviation, and maximum range variability across a 5-test matrix.
High-frequency continuous load monitoring captures the instantaneous tensile separation peak within milliseconds of crosshead reversal.
Additional Commentary
Automated dwell-time circuits ensure identical contact wetting periods, removing human timing errors entirely from the dataset.
Maintain the separation speed precisely at 10 mm/s; even minor velocity drifts alter the viscoelastic peeling response of the polymer.
Common Pitfalls
Using a scratched, pitted, or improperly cleaned probe tip, which drastically alters the true interfacial contact area.