Overview
ISO 15107:1998 is an international standard developed by the International Organization for Standardization (ISO) that specifies a method for determining the cleavage strength of bonded adhesive joints. This standard applies primarily to comparing adhesives and is not intended for use in design purposes. The method captures the average force per unit width needed to gradually separate bonded supports using a controlled fracture mechanism in tensile mode.
This standard is essential for quality control, research, and adhesive performance evaluations across industries where bonded joints are critical. It sets clear guidelines on specimen preparation, testing apparatus, and reporting to ensure uniformity and comparability of results.
Key Topics
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Scope and Purpose
ISO 15107:1998 defines a test method exclusively for comparing adhesives’ cleavage strength, not for structural design applications.
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Definition of Cleavage Strength
The cleavage strength is defined as the mean force per millimeter of bonded joint width required to initiate and propagate joint separation using a wedge or equivalent method.
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Test Principle
The bonded specimen is loaded in tensile mode with stress applied eccentrically to induce a mode 1 fracture (opening mode), producing a controlled cleavage failure along the adhesive joint.
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Specimen Requirements
- Supports can be metal, rigid plastics, fiber-reinforced plastics, wood, or wood-based materials.
- Specimens must comply with specified dimensions and include proper surface preparation aligned with ISO 4588 for metals and ISO 13895 for plastics.
- Adhesive thickness should be controlled and documented, often using glass beads or calibration foils.
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Testing Apparatus
- A tensile testing machine with controlled displacement speed (0.1–10 mm/min, typically 1 mm/min) and precise force measurement (accuracy ±1%).
- Fixtures that allow automatic alignment to ensure vertical stress application relative to the adhesive joint.
- Calibrated according to ISO 7500-1 for metals or ISO 5893 for plastics and rubber.
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Test Execution
Specimens are loaded until failure, with continuous recording of force and displacement. The peak load is used to calculate cleavage strength.
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Reporting
The test report must include adhesive details, support materials and preparation, adhesive joint thickness, test conditions, number of specimens, average cleavage strength, fracture type per ISO 10365, and relevant graphical data.
Applications
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Adhesive Comparison and Quality Control
ISO 15107:1998 provides manufacturers and laboratories a reliable protocol to compare different adhesive formulations based on cleavage strength under controlled conditions.
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Material Research and Development
Researchers use this method to evaluate how changes in adhesive chemistry or substrate preparation affect joint strength.
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Adhesive Performance Benchmarking
Enables benchmarking against industry standards or competitor products, aiding in product selection and improvement.
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Process Optimization
Helps optimize surface treatment and adhesive application processes by assessing their impact on cleavage strength.
Related Standards
- ISO 4588:1995 – Guidelines for metal surface preparation prior to adhesive bonding
- ISO 13895:1996 – Surface preparation of plastics for adhesive bonding
- ISO 291:1997 – Standard atmospheres for conditioning and testing of plastics
- ISO 9142:1990 – Laboratory aging conditions for bonded assemblies
- ISO 10365:1992 – Designation of types of fracture surfaces in adhesives
- ISO 7500-1 – Verification of static uniaxial testing machines
- ISO 5893:1993 – Test machines for rubber and plastics – tension, bending, compression
Keywords: ISO 15107, adhesive testing, cleavage strength, bonded joints, tensile test, adhesive comparison, joint strength determination, surface preparation, mechanical testing standard, adhesive quality control, fracture testing, mode 1 fracture.