At a time when customers can choose between e-books or print books, today’s print and publishing market is competitive. But despite the growth of digital communications, print still remains the most popular format for books.

With the print industry showing no signs of slowing down, there is little room for quality issues. Books must be constructed to meet consumer demands. Printers must ensure books are bound to withstand a range of temperatures, such as high heat or cold during transport. They must also hold up to user wear and tear.

When selecting bookbinding adhesives, you’ll often come across attributes such as excellent “page-pull strength” and “flex characteristics.” This relates directly to the quality of the book and how well it will endure wear and tear by the customer. Page-pull and flex tests are the two most commonly used QC tests that help simulate end user conditions.

The page-pull test measures the amount of force, typically in pounds, it takes to break the page binding. A testing machine pulls a page perpendicular to the spine. The amount of force required is measured on the gauge. The higher the value it takes to pull the pages, the better. Pull testing is usually performed on middle pages and at both ends of the book.

bookbinding adhesive

The page-pull test pulls a page away from the spine.


During the flex test, another testing machine “flexes” the page, rocking it back and forth. It counts the number of times a page can sustain the motion before pulling away from the spine. Some printers, such as those used for yearbooks and other memory books, set high standards for the number of flexes that can occur before failure.

The flex test “flexes” the page by rocking it back and forth.


A book must not only catch a buyer’s eye on the shelf, but it must be durable to withstand extreme temperatures and abuse. Page-pull and flex tests allow printers to continuously monitor the performance of adhesives to ensure that consumers receive quality bound books.

Our technical analysts are available to discuss the specifics of your application and help you find the best bookbinding solution. For more information about bookbinding or to inquire about our selection of bookbinding adhesives, contact us at 1-800-844-1740 or use the contact form below and one of our adhesive experts will be happy to help you.