Assessing the Adhesive Safety of Double-Sided Tapes
Double-sided adhesive tapes are increasingly coming into focus as indispensable components across various industries. Previously, mechanical joining techniques such as screws, rivets, and welding were dominant. However, with the emergence of lighter materials, more complex designs, and the pursuit of more efficient manufacturing processes, adhesive tapes are gaining importance. Industrial double-sided adhesive tapes, in particular, have proven to be highly versatile solutions for not only permanently bonding materials but also achieving aesthetically pleasing finishes. Companies in sectors such as automotive, electronics, aerospace, and others are increasingly turning to these adhesive solutions to reduce weight, shorten assembly times, and enhance the overall performance of their products.
The reasons for this are manifold: Adhesive tapes enable even distribution of stresses across the entire joint, leading to improved stability. They also offer greater design flexibility, facilitating the bonding of materials with different properties. Moreover, they contribute to noise reduction and vibration damping, which is particularly crucial in the automotive sector. Given these developments, the precise evaluation of adhesive tape performance is becoming increasingly important, underscoring the need for new innovative testing methods in the adhesive industry.
In the realm of assessing the suitability of double-sided adhesive tapes, manufacturers consistently prioritize peel resistance tests14,15. It is argued that, in conjunction with adhesive tensile strength16 and shear strength17-20 tests, this method adequately captures minimum adhesive properties. The emphasis is on speed and cost reduction. However, given the prolonged presence of these test methods in the market and the emergence of new innovative approaches, evaluating the efficacy and dependability of established methods becomes imperative. This article introduces an innovative testing and evaluation methodology, initially applied to double-sided adhesive tapes by two major tape manufacturers. Table 1 provides an overview of common test methods, using tapes from Company A as a reference point.
Although these methods remain prevalent, they suffer from significant limitations as they overlook the intricate interactions at the interface crucial for assessing bond performance and reliability. To address these shortcomings, this article introduces a validated test method from FRACTURE ANALYTICS. Known as the MCT method21, it enables testing of all typical load types (crack opening, longitudinal shear, transverse shear) either individually or in combination. However, the most notable feature is its capability to capture stable test curves, even with brittle materials. This sets it apart from other conventional test methods available. Additionally, it offers broader evaluation possibilities not covered by traditional methods14-20. The MCT method has already been incorporated into the standard testing protocol at FRACTURE ANALYTICS.
Manufacturers’ reliance on traditional standard test methods14-20 often stems from historical factors. Cost minimization and the principle of minimum effort typically govern testing policies in this context. Scientific methods with higher requirements are often not prioritized in this cost-driven industry, as sales take precedence and there’s often a lack of appreciation for the added value of new innovative test methods. FRACTURE ANALYTICS conducted a correlation analysis to illustrate some of the problems resulting from previous measurement methods. The analysis compared adhesive tape thickness with peel strength and adhesive tensile strength. The results were surprising, indicating that relying solely on peel tests is not advisable.
Source: Adhesive & Sealant Magazine and Dr. Martin Brandtner-Hafner, Fracture Analytics