How well disposable hygiene products—such as diapers for baby care and adult incontinence—perform under the demands of daily life is important to maintaining product integrity and retaining consumer confidence. Many hygiene products have bonds that are exposed to stresses in a lap shear configuration, where a force pulls the two materials being bonded in opposite direction along the same plane. This can happen when stretch features are engaged, such as when soiled articles are removed, clean ones are applied, and in movement during use. Shear strength is extremely important to both consumers and manufacturers of hygiene products.
The static shear hang test involves two materials bonded with an adhesive. One material is hung from or clamped to a bar, while a weight is clamped to the bottom of the other piece. The test measures time to failure due to lap shear, or how long it takes for the pieces to pull apart. This test can be run at a specific temperature, such as body temperature, to simulate a hygiene product in use.
In a dynamic shear test, the two materials are pulled apart in a shear configuration at a set speed until failure. The force at failure is measured, and the failure mode, or how it failed, is noted.
The goal is to create an adhesive that is at least as strong as the substrates to which it is applied, or the shear stress for the time and temperature it will endure. To learn more about the shear strength of the adhesive you are using in your products, ask the manufacturer to share their shear strength test results.
As your adhesive supplier, Bostik is also able to emulate your line conditions to make recommendations and help ensure our adhesives will perform as intended.
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