Issue Twenty-two, Winter 1999 Understanding the Facts About Adhesive Binding By Brandon Rasch, Vice President © 2001 Bookbinding...Literally the term may be defined, from a historical viewpoint, as "a process of joining together a number of leaves or folios within covers to form a codex or book," (as opposed to a roll or scroll). Many well-known works have been gathered in sections to form a book—The Bible and the Koran to name a couple. Over thousands of years, this process has evolved—from etching in stone tablets to high speed 6 color offset printing—to meet ever-changing needs of writers, publishers, printers, bookbinders and, most of all, the public. From early times, bookbinding was a highly respected art form. Ancient editions of The Bible represent some extremely ornate decorations and have become valuable as collectors' items. The gamut therefore ranges from the very valuable to the ten cent novel. Actually the ten cent novel is the bookbinding industry's answer to the proliferation of books at an economical price. In fairly large quantities, some book products can be gathered, bound (glued together) and trimmed for approximately ten cents. This form of bookbinding is generically known as perfect binding. In reality, perfect binding is one of many forms of adhesive binding. According to Webster, adhesion is "the act or state of being united" It is "molecular force exerted across the surface of contact between unlike liquids and solids which resist their separation." Simply put, it means clinging, sticking fast, tenacious. In adhesive binding, the signatures (a group of pages printed on one sheet) are gathered in proper sequence; the spine or "backbone" of the book receives a "grind" so the adhesive can penetrate into the paper; a coating of adhesive material is applied to the prepared spine; and then the cover is applied to permanently bond the leaves together within the cover. The first mention of adhesive binding, as the term is used, appeared in a patent issued in 1887 in the United States to Horace L. Arnold. After 100 years we are now confronted with terms such as Otabind, PUR, EVA, Perfect Binding, Lay Flat, Burst Binding, RepKover, Falberg and terms so numerous it would be impossible to name them all. As a purchaser or seller of these products, how do you know what to buy or sell, when to buy or sell it, and how much should it cost? In the following paragraphs I will attempt to concisely explain the answers to these questions. As mentioned earlier, adhesive binding is a generic term that can be used to describe only in general terms the form of a final finished product. Within the term "adhesive binding" one would find several major categories. They are PUR binding, perfect binding, cold emulsion binding, double shot hot melt binding, otabinding and sewn book block soft cover binding. PUR Binding PUR is relatively a new term as it refers to bookbinding. Actually, PUR is a hot melt adhesive similar to EVA hot melts, but the adhesive is manufactured with polyurethene reactive material (PUR). As the adhesive product dries a natural chemical reaction occurs after the glue is exposed to moisture in the air. The results of the chemical reaction creates a superior bond within the fibers of the paper giving the book a greater pull and flex strength. In most but not all product situations the books are more durable and lay flatter when opened than a typical EVA adhesive product. The disadvantages of this adhesive are that the cure time requires that the books not be used for almost 24 hours after application and the cost is slightly higher. Care should be taken when selecting this type of binding because in many instances the finished product does not require the additional cost associated with the application process. Perfect Binding Perfect Binding is a hot melt adhesive binding. The term itself was developed by the Sheridan Bookbinding machinery company in 1911 when it attempted to overcome the disadvantages of cold emulsion while retaining the desirable characteristics of pull strength and flexibility. The results achieved over the past 80 years have permanently elevated perfect binding to its place of prominence. Advances in plastic hot melts have driven the marketplace to refer to all adhesive binding as perfect binding, rather than ranking it simply as part of the adhesive binding family. Perfect binding with higher end EVA (hot melt) glues provide page pulls and flex characteristics equal to cold emulsion. The few disadvantages can all be overcome through proper planning at the design stage. The most important advantage of perfect binding is its high speed and relative low cost. Cold Emulsion Binding This type of adhesive binding uses a polyvinyl acetate commonly dispersed in the form of solid resins and water. The water in the glue itself makes it near impossible to bind and trim in-line at high speed, even with high frequency dryers. However, as a result of the water base of both the glue and the paper, superior flex and pull strength characteristics make cold emulsion the most durable method of adhesive binding with the exception of sewn book blocks with soft covers. Double Shot Hot Melt Binding Binders continually strive to produce a better book. Some authorities claim that improved construction of the book block can be accomplished by applying a double coat of glue to the spine of the book after spine preparation. The first coat is a primer coat of glue then the block passes over a second application roller and the final adhesive coat is applied over the primer coat. This process is known in the industry as double shot hot melt. At RGSC we feel that with proper planning of your book project any necessity of this process is eliminated by using either PUR adhesive or high end EVA products. Both styles will result in a significantly reduced purchase price. Otabind Otabind is a process of binding patented originally by Otavia Publishing in 1981 and now licensed by Gerard Hexpoor. Basically, the books are gathered; glue is applied to the spine; then, the book block is capped covering only the glue. Next, the capping is side-glued and a cover is applied, adhering only to the side glue, detached from the spine. This process has been very successfully marketed as a "lay flat binding." By having the cover detached from the spine, the books have somewhat of a tendency to lay flatter, due to the lack of resistance of the cover glued to the spine of the book. The disadvantages of Otabind are that the binding equipment is very expensive, that the process requires the producer to purchase a license from the patent holder, and that generally it is compared to the pull and flex test of perfect binding. The greatest disadvantage is cost. Sewn Book Block with Soft Cover With the advent of very high-speed signature sewing machines a very popular and very durable product has been developed in the binding industry. The product is generally a simulation of case binding but with a reduced selling price due to the use of a soft cover very similar to PUR and perfect binding. The process requires all of the same steps as perfect binding but prior to the actual cover being applied to the books the signatures are sewn together creating a book that will withstand the most abusive reader. This product may be expected to perform functionally for the life of the reader but has a great disadvantage in competitive cost. Although the cost to produce this type of book is much lower than a library bound book, it remains significantly higher than any other method discussed in this paper. Additional information is available from RGS on any of these processes. Just call us at 713 or 800-785-5750 or Email us your questions.   About Rasch Graphics | More Information PUR Binding | Perfect Binding | Saddle Stitching | Mechanical Binding Tab Cutting | Support Services | The Finishing Touch Newsletter EMail RGS | Home Page 7211 N. Gessner Drive • Houston, TX 77040-3143 Phone: 800 / 713-785-5750 • Fax: 800 / 713-785-5801