What is the glue on the side of the book?

What is the glue on the side of the book?

Some books that are not too thick have a layer of glue one or two millimeters thick on the side. What is that?

Hot melt glue!

Nowadays, eva-type hot-melt adhesives are generally used to stick the sides of books, and pur-type hot-melt adhesives are also used, but the cost of using pur hot-melt adhesives will be slightly higher. The process of gluing the spine of the book is as follows: after the pages are folded, the spine is milled (the common understanding of milling is to smash the pages on the spine of a certain depth to facilitate the penetration of glue), and then apply glue and press it tightly. . After this process is completed, wait for the glue to dry on the back of the book, and the binding step of the book is completed.

However, if the pages of the book are difficult to stick, and it is easy to peel off the pages by directly milling and gluing on the back, it is necessary to lock the thread before gluing, and then gluing, so as to improve the firmness of the spine. In addition, thick books also need to be locked first.

I saw someone asking: Can a book that has been perfect bound be re-bindered? – Theoretically it is possible! But trouble, consider whether the depth of the reserved gluing spine is not enough, and the back of the book to be re-glued must also be flattened.