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EVA Binding vs. PUR Binding
Adhesive application is a crucial step in the binding process, as it dictates the longevity of the book and its pages. The glue is often applied to the spine of softcover and hardcover books, and the type of adhesive glue makes more of a difference than one might think. There are two adhesives used for perfect binding, EVA adhesive, and PUR adhesive, and there are a number of reasons why you may choose one over the other.
EVA, also known as Ethylene Vinyl Acetate is a method that has been used for many years and is known as being a more traditional adhesive technique, as it has been around much longer than PUR adhesive. Great for simple operations, EVA adhesive has a faster curing time which allows for rapid turnaround on projects. More benefits of this product include crack resistance, resilience, durability, UV resistance, and light stability. As far as the type of paper this glue functions well with, it is not recommended for books with thicker stocks and rather is best used with offset paper. EVA is a very safe and simple option for perfect binding adhesive.
PUR adhesive stands for polyurethane-reactive adhesive and has become increasingly popular over the years. However, the application of this product is much more specific. PUR adhesive is a moisture-curing product, meaning that it draws moisture out of the air. In order for glue not to cure overnight, the system must be sealed every night to avoid the PUR adhesive from coming into contact with air. In addition to its special attention during the application, PUR is also more expensive than EVA adhesives, however, only half of the thickness needs to be applied to books. This glue dries clear, leaving a very appealing look to perfectly bound products.
EVA vs. PUR
As stated before, an obvious benefit to EVA binding is its cost-effectiveness. EVA glue works especially well when binding thread-sewn books and other standard projects. Using EVA is safer and easier than PUR adhesive, requiring less overall maintenance to the system used. Minimal waste is produced when using this method since these hot melts are able to be re-melted many times, unlike PUR adhesive. However, its ability to re-melt means that it could melt if a book is left in extreme heat. In extreme cold temperatures, they’re also more likely to crack.
After looking at the basic properties of both types of glue, how do they differ? PUR adhesive is generally more expensive and calls for more maintenance to equipment to avoid curing throughout the binding machine. While more expensive, PUR-bound books are high quality with great lay-flat qualities, require less overall glue, and dry clear. When considering PUR adhesive, it’s important to note that MDI is emitted during the curing process, which can be harmful to human health. MDI levels can be regulated and tested with special equipment.
It’s clear to see that there is no perfect solution to perfect binding adhesive. While PUR adhesive has grown in popularity since appearing in the print industry around 1990, it still is not the only option. EVA will continue to be an option for bookbinding, especially with threat-sewn books. Ultimately, when deciding which glue is best for a specific project, things such as book thickness, product use, and budget should all be considered. At Update Ltd, we carry both PUR and EVA spine glue for your bookbinding needs. Contact us today to purchase! 1-800-229-0009