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D3759 – Standard Test Method Technical Guide
ASTM D3759/D3759M is the standard test method for measuring the tensile strength at break (breaking strength) and stretch properties (elongation) of pressure-sensitive tapes. This method covers multiple procedures designed to accommodate various tape backings, including standard backings, high-strength filament-reinforced backings, and high-stretch materials. All procedures strictly utilize a constant-rate-of-extension (CRE) testing machine. The values stated in either SI or inch-pound units are regarded separately as standard, and conversions between the systems must be conducted carefully as they are not exact equivalents.
📐 Specimen Types and Test Geometry
Specimens are typically cut to a width of 25.4 mm (1.0 in) with a length sufficient to provide an initial jaw separation of 127 mm (5.0 in) for standard procedures. The standard mandates testing in both the machine direction (MD) and cross direction (CD) to fully characterize the tape. For Procedure A, the strip is mounted between two flat clamps aligned in a straight plane. For Procedure B, designed specifically for high-strength filament reinforced tapes, the specimen is applied to two rotating drums to prevent clamp slippage and ensure an accurate breaking strength.
| 🟦 Parameter | 📏 Procedure A (Standard Tapes) | ⚡ Procedure B (Filament Tapes) |
|---|---|---|
| Specimen Width | 25.4 mm (1.0 in) | 25.4 mm (1.0 in) |
| Grip Separation | 127 mm (5.0 in) | N/A (Rotating Drum) |
| Elongation Limit | < 200% | N/A (High Strength) |
| Mounting Method | Flat Clamps | Rotating Drums |
⚙️ Procedure and Speed Selection
The selection of the correct procedure depends entirely on the tape backing. Standard pressure-sensitive tapes with an anticipated elongation under 200 % follow Procedure A, which uses a crosshead speed of 305 mm/min (12 in/min). For high-strength filament reinforced backings, Procedure B employs a slower speed of 127 mm/min (5 in/min) with the drum clamps to ensure the specimen is properly engaged without stress concentration. Force and elongation are strictly recorded at the moment of breakage. Users should note that the standard also aligns with international methods including AFERA 4004/4005, EN 1940/1941, and PSTC 131.
⚠️ Important Note on Units: The standard explicitly states that SI and inch-pound values are not exact equivalents. For example, 12 in/min converts to 305 mm/min, but conversions must be conducted with precision to maintain the integrity of the test results.
📊 Measured Properties and References
The primary properties reported are Breaking Strength (the maximum tensile force at break, reported in N/10mm or lbf/in of width) and Elongation at Break (expressed as a percentage of the original grip separation). A unique feature of this standard is the determination of the “F” Value, which measures the tensile force required at a specified elongation (e.g., 5% or 10%). This method references several key standards for quality assurance, including D996 (Terminology), D4332 (Conditioning), and E4 (Force Verification of Testing Machines).
| 🎯 Measured Property | 📐 Units (Typical) | 💡 Calculation Method |
|---|---|---|
| Breaking Strength | N/10mm, N/25mm, lbf/in | Maximum force recorded during the test. |
| Elongation at Break | Percent (%) | (Increase in length at break / 127 mm gauge length) × 100 |
| Force “F” Value | N, lbf | Force recorded at a defined elongation point. |
✅ Best Practice for Replication: Conditioning per Practice D4332 (23 ± 2°C, 50 ± 5% RH) for a minimum of 24 hours is mandatory. A minimum of five replicates per sample and direction is recommended to ensure statistically significant data, in accordance with Practice E122.
❓ Frequently Asked Questions
🔍 What is the difference between Procedure A and Procedure B?
Procedure A is for standard tape backings with an elongation under 200%, tested with flat clamps at 305 mm/min. Procedure B is specifically for high-strength filament reinforced tapes, which are tested using rotating drum clamps at 127 mm/min to prevent slippage and obtain a true breaking strength.
💡 What does the “F” value represent in this standard?
The “F” value is a unique provision in D3759. It measures the tensile force required to stretch the tape to a pre-determined elongation. This is particularly useful for quality control in applications where the tape must maintain a specific holding force at a specific stretch level.
© 2026 TNLab — This article is a technical interpretation for reference only. The original standard as published by ASTM International takes precedence.