As a publisher you might be hearing a lot these days about PUR binding. And you may also be wondering whether it makes sense for your titles.
So what exactly is PUR? Polyurethane or “PUR adhesive” glue came along in the late 1980′s and was used in other industries such as furniture and automotive before being discovered as useful in book binding applications. Its main advantage, a lower freeze point and a higher melting point, has significant advantages, especially for publishers who ship books globally.
Today PUR adhesive is gaining traction in the marketplace as publishers and consumers desire books that will keep the pages bound together more securely over the life time usage of the book. In fact, since installing its PUR binder over three years ago, PG now uses PUR adhesion for about 40% of its books — both hardcover and softcover.
Even fans of Smythe binding, in which the signatures of the book are sewn together, are recognizing PUR’s value, and are moving over to it. According to an article in American Printer, (October, 2003), here are just a few benefits of PUR binding:
- Lie-flat qualities
When applied at its recommended thickness
— 0.01 inch — PUR is considerably more flexible than standard EVA hot melts. This ability to lie flat when open allows for hands-free reading.
- Heat and cold resistance
PUR adhesive has a lower freeze point and a higher melting point than any other adhesive on the market. Books bound by PUR will not fail at extreme temperatures — even over 200°F or under -40°F. These properties were especially important to customers who send books globally where temperature extremes are commonplace.
- Less wrinkling of backbone
Binding cross-grained paper with standard hot melt adhesives causes considerable wrinkling in the book’s gutter area. PUR’s lower operating temperature, however, doesn’t drive paper moisture away from the backbone. PUR is also somewhat malleable as it cures, allowing the paper fibers to return to their original orientation.
- Less “chip-out”
Since PUR is applied at half the standard thickness of hot melt, there is much less chance for the material to build up on trimmer knives and nick the cover material during trimming.
- Square backbone
Because only a small amount of PUR needs to be used for binding, less adhesive is squeezed out when the cover station and side clinchers attach the cover and form the back.
- Cost savings
One of the most significant reasons for considering PUR adhesion is the cost savings. According to a study in Europe, binders can realize a cost savings of 30 percent to 40 percent by milling off the backbone of the folded signatures and then gluing them with PUR.*
*from American Printer, October, 2003