STATISTICAL ANALYSIS OF ADHESIVE LAYER THICKNESS` DISTRIBUTION ON PERFECT BOUNDED BROCHURES

Abstract

Perfect binding has become one of the most popular binding methods for lowand mid-range graphic products, but with the appearance of new adhesives and application techniques, it is more and more important for the production of high quality, short-run products too. The influencing factors of perfect binding quality are numerous, involving different parameters and aspects of graphic production. Along the paper`s properties, book block parameters and spine preparation technique, the used adhesive and its application could have a direct influence on the paper/adhesive interaction and therefore on the adhesive bond quality, i.e. binding strength, too. In this study, a statistical analysis of overall adhesive layer thickness and its distribution along the book block spine has been performed. This analysis was aiming to investigate the influence of the book block volume and two gluing system set-up parameters, the nominal adhesive thickness and gluing length modification, on the adhesive application consistency. The statistical analysis showed that the book block volume had a significant influence on the obtained results of overall adhesive layer thickness (based on the p-value of 0.05) and the adhesive layer became more evenly applied to the block spine by increasing the book block volume. The influence of the nominal adhesive thickness and the glue length modification were also statistically significant (at level p<0.05) on the obtained overall adhesive thickness, however, the corresponding post hoc tests showed that not all the observed groups differed significantly from each other. In addition, the obtained results for adhesive distribution along the book block spine showed more uniform application for the higher values of nominal adhesive thickness and glue length modification. Key-words: perfect binding, adhesive layer, book block spine