A manufacturer of adhesives and fillers faced challenges with yellowing failures in their products, particularly in harsh climates like the Middle East. By using Q-Lab’s weathering tests, they gained valuable insights into product performance, allowing them to improve durability and expand their market reach.
Overview and Problem Statement
A manufacturer specialising in adhesives and fillers sought to better simulate the yellowing failures of their products observed in the field. These products are used in the bonding, filling, and repairing of materials such as stone, concrete, ceramic, and coatings in industries including automotive, architecture, and more. Common failure modes include colour fading, gloss loss, mechanical strength reduction, peeling, and cracking. This issue was not primarily related to warranty claims but rather an opportunity to expand their market presence in challenging geographic environments, particularly the Middle East. The manufacturer’s technology, which is used outdoors in diverse climates globally, relies on polyester and polyurethane epoxy resins.
Testing Description and Results
The manufacturer turned to Q-Lab for assistance in finding a more reliable way to simulate and evaluate the yellowing of their products. With Q-Lab’s expertise, they conducted comparative trials using both QUV and Q-SUN xenon arc test chambers to determine which method better reflected the failures observed in the field. The testing was performed over 500 hours in accordance with ISO 4892-2 (xenon) and ISO 4892-3 (fluorescent UV), following Cycle 1 of both standards.
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QUV Testing: A light and condensation cycle was used with UVA-340 lamps. The light step lasted 8 hours with an irradiance setpoint of 0.76 W/m²/nm at 340 nm, maintained at 60°C. The condensation step lasted 4 hours at 50°C.
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Q-SUN Testing: An alternating light/light+spray cycle was carried out using Daylight-Q filters. The cycle consisted of 102 minutes of light exposure at 60 W/m² TUV (300-400 nm) at a chamber temperature of 38°C and a relative humidity of 50%, followed by 18 minutes of light exposure combined with water spray.
After 500 hours of testing, substantial changes were observed in the test specimens, both in QUV and Q-SUN environments. The results showed significant degradation in both sets of tests, which provided valuable insight into the performance and durability of the materials under simulated harsh conditions.
Further analysis revealed that the epoxy resin results showed noticeable yellowing and cracking in the fluorescent UV tests, which were more pronounced compared to the xenon tests. The fluorescent UV testing also demonstrated colour fading and yellowing that more closely resembled the field failures observed by the manufacturer.
Similarly, results for acrylic-based formulations, particularly polymethacrylate and epoxyacrylates, showed that the UV fluorescent method aligned more closely with the real-world degradation patterns, producing more severe yellowing than the xenon test.
The tests also indicated that polyurethane and polyester formulations exhibited slightly more yellowing when subjected to the fluorescent UV cycle, similarly mimicking the failures seen in field applications.
Benefits of Testing
Following these comprehensive test results, the manufacturer made the decision to purchase a QUV tester for internal R&D purposes, with the aim of reformulating their products, particularly the epoxy resins. The QUV tester provided them with a reliable, repeatable method for performance testing, with results that closely matched real-world conditions, a capability they had not previously had. This new approach allowed the company to compare their newly formulated products against older versions as well as competitor products, offering valuable insights into product performance.
While the manufacturer has not publicly shared specific business outcomes, it has been confirmed that the QUV tester paid for itself within a short period. Moreover, it played a crucial role in helping the company expand its market share in targeted regions, particularly those with extreme environmental conditions, contributing significantly to their competitive advantage.
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