Perfect binding
In the course of the book production , the raw sheets are collected by the bookbinder , trimmed and the open spine is strengthened as a result of the adhesive binding . This type of binding, carried out by means of cold or hot glue , has generally prevailed over the much more durable thread stitching because of the cheaper production. While the book block can usually be opened flat with thread-sewn books , this advantage has to be foregone with adhesive binding.
In small businesses, manual adhesive binding using the Lumbeck method and so-called block gluing is still very complex. Automated perfect binding enables automatic book production in a binding or book line through the seamless transition of several production steps. In mechanical adhesive binding the book blocks are using a ( hot melt , dispersion adhesives or PUR ) adhesive bonded. Large editions can be produced and offered extremely inexpensively in a short time thanks to very high machine speeds. The application of the method is both brochures ( Paperbacks ) and catalogs as well as in hard-cover versions ( Verlag cover applied).
historical development
Until the advent of web-fed rotary printing around 1863, books and manuscripts were bound by hand thread stitching. The rapid increase in book production made faster machine production necessary. The use of the first thread sewing machine around 1885 was only the first step towards cheaper marketing. The use of wire stitching machines to fix the spine of the book was abandoned after a few decades when the initially good durability quickly turned into the opposite after massive use. After trimming the spine of the book was generally viewed as deliberately destroying the core of the book, in the interwar period people made do with briefly pushing the wire stitching through the entire block. Although this type of binding or thread sealing kept the book layers intact for later manual thread binding, it was not a permanent solution in terms of quality.
The circumcision of the back was finally accepted after Emil Lumbeck from Remscheid developed a manual cold glue technique (as opposed to the industrial hot glue technique) in 1936 , which is still called Lumbecken today. Lumbeck can therefore be seen as a pioneer of the modern paperback.
Process types of adhesive bindings
- Without destroying the gutter (so-called quarter-arch gluing)
- z. B. Seam gluing - glue is applied to the waistband of the sheets, the strength achieved is very high.
- Partial destruction of the gutter (so-called Flexstabil binding)
- z. B. the Flexstabil binding invented by Josef Ricke - the bow is separated in the middle at the waistband, the bows remain connected at the foot and at the head bridge. A strip of paper is glued in between the milled area, then the envelope follows. Since the gutter is still partially preserved, the pages tear the leaves from not so easy.
- Vivat Liber process - The back is provided with a special patented profile cut that avoids paper dust. This increases the stability.
- Destruction of the gutter (narrow milling or trimming of the book spine)
- The sheets are separated, glue is applied directly to the sheets (typical paperback).
Manual adhesive binding
Lumbeck method
The hand-made Lumbecken is carried out with cold glue and, with good craftsmanship, shows quite durable results. Ideal conditions are only given for letterpress and thin printing paper with the correct direction of the paper. The direction of travel is extremely important in adhesive binding, it must always be parallel to the spine of the book. The individual pages arranged to form a book block are pushed straight and the lower third is clamped in a press (wooden block press, modern Lumbeck press) at the right angle. As a result, the unpressed pages of the book spine open to form a fan that slopes down on both sides. This fan is placed over the press with one hand and the sheets of paper are fanned out so that the individual sheet has an adhesive edge between 0.3 mm and 1 mm. These areas are coated in a star shape in an outward direction with cold glue that is not too watery. The process is repeated in the opposite direction, before the whole pack is brought into the desired block shape in the middle with both palms and pressed on. Then a previously prepared gauze is placed on the glued part , glued over again and the now fully adhesive-bound block is removed from the press for the final trim and placed at the right angle to dry.
Block binding
A special type of mostly manual cold gluing is the block binding (not to be confused with the block binding alias Japanese binding ), i.e. H. the temporary holding together of individual sheets of paper to form a writing pad. Special white glue is used, which creates a good connection to the cellulose fiber of the paper, but remains elastic for a long time and gives way under the action of tension (tearing off a sheet). The block binding, which is easy to carry out, is used for end products that do not require a long shelf life, e.g. B. intended for folders school books, all types of notepads, desk or wall calendars and the like. The stack of paper trimmed to size is carefully pushed straight, placed on top of each other at several angles and pressed. The surface that has now been created, the back of the block , is roughened with a sharp blade and coated with cold glue. After the drying time, the hardened block back can be cut through with a hand knife in any thickness. The individual sheets of a glued block can be easily peeled off compared to the higher quality Lumbeck adhesive binding.
Machine adhesive binding
Hot glue technique
In the heat-sealing technique (also hotmelt ) are solid at room temperature, granulated ethylene vinyl acetate - copolymers ( EVA hot melts ) are melted at about 170 ° C and must during the open time (the time in which they are machinable not yet cured, and, to 60 seconds) can be applied to the spine of the book.
Polyurethane adhesives
Since glues such as hotmelt or dispersion glue (cold glue; white glue) are not very temperature-resistant (hotmelt can be reheated and cold glue breaks at very low temperatures), polyurethane hotmelts (PUR) are increasingly used in industrial production . These are processed at approx. 130 ° C and solidify when cooled. These glues absorb the moisture in the air for complete setting. The adhesive is transformed into a non-dissolvable urea.
Cold glue technique
The cold glue technique differs from the hot glue technique in that it can be carried out cold with the help of a special white glue . The cold gluing technique is nonetheless very durable, because chemical processes are set in motion during the drying process that connect the individual sheets of paper on the spine of the book or promote the breakdown of the cellulose and bind / weld it in the long term.
Disadvantages of perfect binding
The strength and lifespan of a perfect-bound book can only approximate the quality of a thread-sewn book, even with perfect workmanship and consideration of all relevant factors. In addition to the lower durability against mechanical stress from the outset, the lower aging resistance must also be taken into account, as the adhesive used can become brittle over time.
The technique is generally unsuitable for all thicker calendered papers such as art paper (high-gloss paper), as the coated paper hardly lets the adhesive into the paper structure. If the adhesive binding is used for heavy or even large-format art print books, for folios and atlases, the book can disintegrate into its individual parts with little use. With heavily calendered paper or oil-based paints, the glue can penetrate deeper into the book block than intended. This disadvantage becomes unpleasant after binding, especially with continuous illustrations.
Even with ideal papers, the fibers of which allow the glue to penetrate deeply, there can be considerable disadvantages if the adhesive binding is not used professionally. If the binding was carried out against the running direction of the paper , the dried book block is difficult to open and breaks prematurely. Book blocks with paper pages that run across the gutter are difficult to open because the solidified adhesive "clings" too much and presses the pages together at the gutter. If you overstretch such pages too long when you read them later, the spine can break quickly.
Large companies are always well advised to produce an adhesive sample that tests the subsequent adhesion of the adhesive glue to the paper fiber to be used. Particularly color-intensive full-surface prints, which are printed in the offset process up to the gutter, can lead to poor binding results when using hotmelt adhesives. The mineral oils contained in the printing inks reduce, for chemical reasons, the durability and adhesion of the hot melt. The hotmelts enriched with hydrocarbons are damaged by the oils in the printing ink, which are based on the same chemical basis. This negative interaction, which has been known for a long time, has been counteracted by the development of PUR hot glue systems, but in such cases the use of dispersion cold glue is preferable.
literature
- Dieter Liebau, Inés Heinze: Industrial bookbinding. Verlag Beruf und Schule, Itzehoe 2001, ISBN 3-88013-596-7 .
- Karl Dratva: Expertise for bookbinders , Austrian commercial publisher, Vienna 1966
- Melanie Kubitza: The problem of the restoration of adhesive bindings using the example of the book "Principles of the Science of Color" (1868) , diploma thesis, Cologne, Cologne University of Applied Sciences, 2006
