July 2003: Binding Adhesives

Adhesive binding is one of the most detail-oriented processes in the post press world. There are literally hundreds of adhesive formulas available, and selecting the right one for a particular project is as much a chemistry class as it is a graphic arts process.

All binding adhesives need to be strong enough to hold a book together for years, and flexible enough to allow it to be opened thousands of times. There are three main adhesive families: EVA hot melt, animal-based cold-applied and PUR. Each one has distinct characteristics that make it suitable for certain applications. EVA and PUR adhesives are the most popular and versatile of the three, so we’ll focus on just these two adhesive families:

EVA Hot melt

EVA (ethylene vinyl acetate) is the “standard” adhesive used for perfect binding, and it’s available in many different formulas. As the name implies, EVA adhesives are heated during the application process. EVA adhesives are versatile enough to be used on both coated and uncoated stock, and can be used for more than just perfect binding. For example, a “roundable” hot melt adhesive can be used to create a rounded spine on Smyth-sewn books. Pressure-sensitive hot melt formulas can be used as a side glue for padding and cover hinges.

PUR 

PUR (polyurethane reactive) is the strongest binding adhesive available. Originally designed for use on both furniture and automobiles, PUR adhesive is impervious to both hot and cold temperature extremes. It works with all stocks and coatings including synthetics and UV. PUR is much more flexible than EVA adhesive, making it a popular choice for layflat adhesive binding applications. Lastly, PUR adhesives are applied thinly, which helps prevent wavy spines and other glue buildup problems. 

Unlike other binding adhesives, PUR adhesives require at least 24 hours to fully cure. It’s important to keep this in mind when planning a PUR adhesive-bound project.

Inks and coatings should be knocked out of the spine area on books bound with EVA or cold adhesives. These elements can compromise adhesion when they seep into the binding area, reducing the strength of the bind and the lifespan of the book. Although we still recommend knocking them out, PUR adhesives will form a sufficient bond even if inks and coatings creep into the spine area.

The Riverside Edge

Although it sounds scientific, selecting the right binding adhesive requires experience more than anything else. At The Riverside Group, we specialize in all forms of soft cover and cased-in adhesive binding, and we work with dozens of adhesives on a weekly basis. Let us help you find the best one for your next adhesive binding project.