Adhesive performance test

Adhesive Performance Testing Service – Accredited Evaluation of Bond Strength, Durability, and Environmental Resistance

For Brazilian manufacturers, importers, and quality engineers in the automotive, aerospace, construction, packaging, electronics, and medical device sectors, the performance of adhesive bonds is a critical factor that determines the safety, reliability, and durability of assembled products. Adhesives are increasingly replacing mechanical fasteners and welding in many applications, offering advantages in weight reduction, stress distribution, sealing, and design flexibility. However, the reliability of an adhesive joint depends on many variables – including the adhesive formulation, surface preparation, curing conditions, and the service environment. Our ISO/IEC 17025 accredited laboratory offers a comprehensive adhesive performance testing service that quantifies the shear strength, tensile strength, peel resistance, impact resistance, fatigue behaviour, and environmental durability of adhesive bonds, using a wide range of standardised and customised test methods, in full compliance with ABNT NBR, ASTM, ISO, and customer‑specific requirements. With decades of experience in adhesive characterisation and failure analysis, we provide precise, repeatable, and fully documented test results that are accepted by INMETRO, ANVISA, and Brazilian certification bodies, supporting your product development, supplier qualification, and regulatory compliance.

Adhesive Types and Bonded Assemblies We Regularly Test

We accept a wide range of adhesive systems and bonded assemblies, from simple lap‑shear coupons to complex multi‑layer structural joints. Our test setups are adaptable to various adhesive types, substrate materials, and curing conditions. Common samples include:

• Structural adhesives – epoxies, polyurethanes, acrylics, and cyanoacrylates.
• Pressure‑sensitive adhesives (PSAs) – tapes, labels, and films.
• Hot‑melt adhesives – for packaging, textiles, and woodworking.
• Anaerobic adhesives – for threadlocking and retaining.
• UV‑curable adhesives – for electronics and optical applications.
• Water‑based and solvent‑based adhesives – for general assembly and lamination.
• Silicone and rubber‑based adhesives – for flexible and high‑temperature applications.
• Bonded assemblies – including metal‑metal, metal‑plastic, plastic‑plastic, and wood‑metal joints.
• Bonded composite structures – for aerospace and automotive use.

Core Test Methods – Shear, Tensile, Peel, and Impact Strength

Our adhesive performance testing service covers the full range of mechanical tests required to characterise the strength, toughness, and deformation behaviour of adhesive bonds. The selection of tests depends on the adhesive type, the substrate materials, and the expected service loads:

• Lap‑shear strength (ISO 4587, ASTM D1002, ABNT NBR ISO 4587) – We prepare a standard overlapping joint of two substrates (typically metals, plastics, or composites) with the adhesive applied in the overlap area. The joint is pulled in tension at a constant rate (typically 1‑5 mm/min) until failure. The maximum force is recorded, and the shear strength (in MPa) is calculated by dividing the force by the overlap area. This is the most common test for structural adhesives and is used to compare adhesive formulations and to qualify production processes.
• Tensile strength (ISO 6922, ASTM D897, ABNT NBR ISO 6922) – We bond two cylindrical blocks together with the adhesive and pull them apart in tension along the bond axis. The tensile strength (in MPa) is calculated from the maximum load and the bond area. This test is particularly relevant for adhesives used in butt joints and for evaluating the cohesive strength of the adhesive.
• Peel resistance (ISO 8510‑1, ASTM D903, ABNT NBR ISO 8510‑1 and ABNT NBR 13021) – For flexible substrates and pressure‑sensitive adhesives, we measure the force required to peel the adhesive layer from the substrate at a defined angle (typically 90° or 180°). The peel strength is expressed in N/mm or N/cm. This is a key test for tapes, labels, and flexible laminates.
• Impact resistance (ISO 11343, ASTM D950, ABNT NBR ISO 11343) – We apply a sudden, high‑speed impact load to the bonded joint (using a falling‑weight or pendulum impact tester) and measure the energy absorbed before failure. This test evaluates the toughness of the adhesive and its ability to withstand dynamic loads.
• Cleavage and peel (ISO 14615, ASTM D3807) – For adhesives used in stiff substrates, we measure the resistance to cleavage forces, which simulate the opening of a joint under a wedge‑like load.
• Fatigue and cyclic loading (ISO 9664, ASTM D3166) – We apply a cyclic load (tension‑tension, compression‑compression, or tension‑compression) to the bonded joint at a defined stress amplitude and frequency, and we record the number of cycles to failure (or the run‑out cycles). This provides the fatigue life curve of the adhesive bond, which is essential for structural applications.
• Creep and stress relaxation (ISO 15109, ASTM D1781, ABNT NBR ISO 15109) – For adhesives used in long‑term load‑bearing applications, we apply a constant load (or constant strain) to the joint and measure the deformation (or stress) over time. The creep modulus and the stress‑relaxation behaviour are determined, which are critical for predicting the long‑term performance of the joint.
• Shear strength at elevated and low temperatures (ISO 4587 with temperature chamber) – We perform the lap‑shear test at high temperatures (e.g., 80°C, 120°C) and low temperatures (e.g., -40°C) to evaluate the effect of temperature on the adhesive bond strength.

Environmental and Durability Testing – Simulating Service Conditions

Adhesive bonds are often exposed to moisture, temperature cycling, UV radiation, chemical attack, and other environmental stresses that can degrade their performance over time. Our environmental durability tests provide a realistic prediction of the adhesive's service life:

• Humidity and water immersion (ISO 9142, ASTM D1151, ABNT NBR ISO 9142) – We condition the bonded specimens in a high‑humidity chamber (e.g., 40°C, 95% RH) or in water immersion for a defined period (up to 1,000 hours or more). After the exposure, we perform the lap‑shear or peel test to evaluate the residual strength, which indicates the adhesive’s moisture resistance.
• Thermal cycling and aging (ISO 9142, ASTM D1183, ABNT NBR ISO 9142) – We expose the bonded specimens to cyclic temperature changes (e.g., -40°C to +80°C) or to elevated temperature aging (e.g., 70°C, 100°C) for up to 1,000 hours, and then we test the residual adhesion to evaluate the thermal stability.
• UV and weathering exposure (ISO 4892, ASTM G154, ABNT NBR ISO 4892) – For outdoor applications, we expose bonded specimens to UV radiation and humidity cycles (using a xenon‑arc or fluorescent UV weatherometer) and then test the residual strength to evaluate the UV resistance of the adhesive.
• Chemical resistance (ASTM D543, ISO 2812, ABNT NBR ISO 2812) – We immerse the bonded joints in common chemicals (e.g., fuel, oil, brake fluid, acid, alkali, or cleaning agents) for a defined period, and then test the residual strength to assess the chemical compatibility of the adhesive.
• Corrosion resistance – for adhesives used on metal substrates – We expose the bonded metal assemblies to salt spray (ASTM B117, ISO 9227) and evaluate the effect of corrosion on the adhesive bond integrity.

Failure Analysis and Interpretation – Understanding the Bond Failure Mode

After testing, we perform a detailed examination of the failed joint to determine the failure mode. This analysis is essential for understanding the performance of the adhesive and for improving the bonding process:

• Failure mode classification – according to ISO 10365 and ASTM D5573 – We classify the failure as cohesive (within the adhesive layer), adhesive (at the adhesive‑substrate interface), substrate (within the substrate material), or a mixed failure. We also note the location of the failure (e.g., at the edge, in the centre, or in the fillet).
• Microscopic examination – we use optical microscopy and, if needed, scanning electron microscopy (SEM) to examine the fracture surface – This helps identify the presence of voids, contaminants, or poor wetting that may have contributed to the failure.
• Measurement of the bond line thickness – we measure the adhesive layer thickness to correlate it with the observed strength – An uneven or excessive bond line can reduce the strength.
• Correlation with the substrate surface preparation – we evaluate the surface roughness and the presence of contamination (e.g., oils, oxides) that may have affected the adhesion – This helps determine whether the failure was due to poor surface preparation.
• Interpretation of the load‑displacement curve – we analyse the shape of the curve to determine the ductility or brittleness of the adhesive – A ductile failure (with significant deformation) indicates good toughness, while a brittle failure (sudden, with little deformation) suggests the adhesive is too rigid for the application.
• Recommendations for improvement – based on the failure mode and the test results, we provide recommendations for adhesive selection, surface preparation, curing conditions, or design modifications – This helps you optimise the bonding process and achieve better performance.

Calibration, Traceability, and Quality Assurance

All adhesive performance tests are performed under our ISO/IEC 17025 accredited quality system, with full traceability of force, displacement, temperature, and humidity measurements:

• Calibration of tensile/compression testing machines – load cells, extensometers, and speed – according to ISO 7500‑1, ASTM E74, and ABNT NBR ISO 7500‑1 – The force measurement uncertainty is < 0.5% of the reading.
• Calibration of peel and impact testers – using certified reference weights and standards – The measurement uncertainty for peel force is < 1%.
• Calibration of environmental chambers – temperature and humidity – according to ASTM E220 and ISO 17025 – The temperature uncertainty is < 0.5°C, and humidity uncertainty is < 2% RH.
• Verification with reference adhesives – we test a certified reference adhesive at regular intervals to confirm the stability and reproducibility of the test system – The results are monitored on control charts.
• Interlaboratory comparisons – we participate in proficiency testing schemes for adhesive testing – Our results are periodically validated against other accredited laboratories.

Compliance with Brazilian and International Standards

Our adhesive performance testing services support compliance with the key standards for adhesive bonding in Brazil and globally:

• ABNT NBR ISO 4587 (Adhesives – Determination of tensile lap‑shear strength of rigid‑to‑rigid bonded assemblies) – The main Brazilian standard for lap‑shear testing.
• ABNT NBR ISO 6922 (Adhesives – Determination of tensile strength of butt joints) – For tensile strength testing.
• ABNT NBR ISO 8510‑1 (Adhesives – Peel test for a flexible‑to‑rigid bonded assembly) – For peel strength testing.
• ASTM D1002 (Standard Test Method for Apparent Shear Strength of Single‑Lap‑Joint Adhesively Bonded Metal Specimens) – Widely used for metal‑to‑metal adhesives.
• ASTM D903 (Standard Test Method for Peel or Stripping Strength of Adhesive Bonds) – For peel testing of flexible adhesives.
• ISO 9142 (Adhesives – Guide to the selection of standard laboratory ageing conditions for testing bonded joints) – For environmental conditioning protocols.
• ANVISA and INMETRO requirements – for adhesives used in food contact, medical devices, and packaging – Our tests are accepted for product registration.
• Automotive and aerospace OEM specifications – e.g., VW, Fiat, GM, Ford, Embraer – which define specific adhesive test methods – We can customise our procedures to meet these requirements.

Reporting and Accreditation

All adhesive performance tests are performed under our ISO/IEC 17025 accredited quality system, with full traceability of all measurement parameters. Our Inmetro‑accredited reports are recognised by INMETRO, ANVISA, and various Brazilian certification bodies. Each report includes:

• A complete description of the adhesive, substrates, and specimen preparation (including surface treatment, curing conditions, and conditioning).
• Detailed test conditions (temperature, humidity, crosshead speed, and load range).
• Numerical results: shear strength (MPa), tensile strength (MPa), peel resistance (N/mm), impact energy (J), and fatigue life (cycles).
• Load‑displacement curves and force‑time plots.
• Failure mode analysis and photographic documentation of the failed joints.
• Comparison with the specified requirements and a clear pass/fail conclusion.
• Calibration certificates for all test equipment and measurement uncertainty statements.
• Recommendations for process optimisation and design improvement.

Our reports provide the confidence you need to select the right adhesive, qualify suppliers, and ensure the safety and durability of your bonded assemblies.

Why Choose Our Adhesive Performance Testing Service?

We understand that adhesive bonds are often the critical link in an assembly, and that a bond failure can have serious safety and financial consequences. Our team offers rapid turnaround, flexible test programmes (from simple screening to comprehensive qualification), and clear, actionable interpretation of results – we do not just give you numbers; we explain the failure mechanisms, the influence of environmental factors, and the steps you can take to improve bond performance. We work closely with your design, production, and quality teams to select the appropriate test methods, conditioning protocols, and acceptance criteria for your specific adhesive and substrates. With state‑of‑the‑art test equipment, traceable calibrations, and a highly experienced team, our adhesive performance testing service delivers the accuracy, repeatability, and regulatory acceptance you need to ensure that your adhesive bonds are strong, durable, and reliable. Contact us to discuss your adhesive and bonding application – we will develop a customised test programme that provides the definitive evidence of your adhesive's performance.