The manufacturing world is continually moving forward, and being at the forefront of innovation is key to providing better sealing and adhesives solutions to customers. Glue is an element that many often don't consider, but it is vitally important when producing packaging.
Developing a new type of packaging process or technique requires testing, especially when it comes to the glue that holds it together. Different surfaces and adhesive properties combine in unique ways that may or may not work with your application.
When improving your packaging manufacturing process, here are some of the tests to consider when evaluating an adhesive's effectiveness on a substrate.
For glue to be effective, it has to be able to wet the surface of the substrate it's placed on. When applying glue to a substrate, the glue's wettability is determined by its own surface energy and the substrate. The adhesive needs to have lower surface energy than the substrate to have the glue wet correctly.
A dyne test is one of the best methods for evaluating your materials to ensure your surface can support proper adhesive. A dyne test measures force to determine the surface energy of a material. By measuring the dyne levels, it's easier to see and identify how glue will behave once applied to a surface and how to improve adhesion.
Are you concerned about your adhesive's bonding capabilities? Glue-up tests are an excellent method to test the bonding capabilities of glues to substrates. The test is pretty straightforward. First, the substrate is cut into small sections, and glue is applied to perform drawdowns. After being pressed together, the substrates are allowed to sit at room temperature for 24 hours.
To test the bonds, the substrates are pulled apart. A successful bond means that the glue holds, causing fire tears in the substrate when pulled apart. If no fiber tears are evident, the substrates are held together by a weaker bond that will likely negatively affect product performance.
Not to be confused with a glue-up test, a force test determines the amount of energy needed to pull two bonded substrates apart. The tests are measured in newtons or pound-force to get an accurate reading of the bond's force.
To keep production running smoothly, the effects of heat and humidity need to be considered. Heat and humidity tests are used to measure the amount of curl between the glue and a substrate and how a bond will hold under extreme conditions. Usually, testing is done at room temperature up to 120°F but can be higher depending on the glue and application.
Understanding how both extremes of temperature affect your glue application is critical to your products' longevity. If your product will be exposed to cold temperatures, especially for food and beverage packaging, knowing how your glues and substrates will behave in the freezer is critical.
Freezer tests can reach as low as -40°F. The samples are allowed to sit for 24 hours before being removed. The bond should be immediately tested for flexibility, strength, and other important properties.
At LD Davis, our team takes pride in our ability to help manufacturers test their applications' adhesion properties through our advanced lab capabilities. Our full-service research and development lab has the equipment and expertise to help you test and enhance your adhesive performance. If you need help testing a new glue, application, or production method, let us know.