What is the difference between edge glue and backing glue? The use of two types of adhesives for book binding and Sunlife models

The terms “back glue” and “edge glue” are often heard in book and magazine packaging, but many people cannot distinguish whether it is the same glue with a different name or two completely different glues? Choosing the wrong one not only wastes money, but also directly leads to loose pages and cracked covers. Below, using the actual model of Sunlife, we will explain these two types of adhesives in one go.

1、 First of all, let’s conclude that backing glue and edge glue are not the same thing

Hot melt adhesives are mainly divided into two categories according to their uses:Back glue (book back glue)andEdge glue (side glue)They are applied in different positions, bear different forces, and have different requirements for performance, making them two independent processes of adhesive in book and magazine packaging.

• adhesive backingThe “main adhesive” that is applied to the spine (back) of a book, sticking the pages together to form the book core, bears the main tensile force of the book core, and is the core of the adhesive strength.
• Edge glueApply to both sides of the book block or the outer edge of the spine, used to fix the cover and book block together, prevent loose pages and curled edges of the cover, with less usage and more emphasis on initial adhesion and not using glue rollers.

in a word:The back rubber tube may not stick firmly to the book core, while the edge rubber tube may not seal the cover securely.

2、 Adhesive backing: the core of book core strength

Adhesive backing is the backbone of adhesive bound books. After milling and roughening the pages, the back glue seeps into the spine fibers to form an adhesive layer. Whether the book can be flipped thousands of times without opening depends mainly on the back glue.

The common models of Sunlife book and magazine adhesive are as follows:

Key parameter window for adhesive backing:Adhesive glue 160-180 ℃(Better viscosity and infiltration);Opening hoursRandom speed variation (15-20 seconds for low speeds around 2000 km/h, 5-10 seconds for medium speeds, 2-7 seconds for high speeds over 4000 km/h);Curing usually takes 3-5 minutesWhen selecting, report the “paper type+machine speed” to Sunlife, and receive the model and process card that can be landed.

3、 Edge glue: the “safety rope” on the cover

The amount of edge glue used is much less than that of back glue, but without it, the cover is prone to peeling and curling at the front of the book. Edge glue is more valuedQuick initial adhesion, no wire drawing, and no pollution to the rubber roller。

Sunlife edge glue model 298(Book and magazine edge glue)29B(Homework book/bill edge glue) as the main focus. The common practice in actual production is to use a layer of edge glue to lock the cover and the side of the book block after the back glue is applied and the book block is formed.

Common misconceptions: Use edge glue as backing glue, or simply apply backing glue without edge glue to save time. The former has insufficient adhesive strength and may cause loose pages, while the latter has an unstable cover and is prone to opening during transportation.

4、 Three judgment points when selecting

1. Look at the affected areaThe adhesive strength of the book block depends on the back glue, and the cover is fixed with edge glue, both of which cannot be ignored;
2. Check paper type and machine speedFor copperplate paper and thick books, choose high adhesion adhesive files (such as 396/397 ideas), and for high-speed lines, choose fast fix models;
3. See if there are any flat sharing/special requirementsChoose 391 for 180 ° flat distribution, 39D for quick drying test papers, and 393/395 for multiple materials in graphic stores.

Frequently Asked Questions

Q: Can we just use backing glue instead of edge glue?

A: Small batches and internal materials can sometimes make do, but for official publications, it is recommended to have both back glue and edge glue in place, otherwise the cover and side glue may easily peel during transportation.

Q: Can the back glue and edge glue be of the same model?

A: Usually not recommended. The back adhesive has strong tensile strength and penetration, while the edge adhesive has strong initial adhesion and cannot be rolled, with different performance orientations; Sunlife has two models, 292/296/295/396/397 (backing adhesive) and 298/29B (edge adhesive), based on their intended use.

Don’t just ask ‘which one is the strongest’ when choosing glue, first distinguish whether the rubber tube is for the book slide or the cover. The above Sunlife real model comparison lists the purpose and corresponding models of the backing and edge adhesives at once – if you can’t take them, tell Sunlife the book sample and machine speed, and match the model and process card according to the purpose, which is much more stable than testing the adhesive by feeling.

*This draft is for official website SEO and is awaiting manual review. The model and parameters are sourced from the Sunlife training material index and are not fabricated; The precise process values are based on the accompanying process card. The content scope is limited to hot melt adhesive lines and does not involve skinning. Overlapping risk warning: Adjacent to 2432 “Model General List” and 2715 “Paper Model Comparison”, but this article focuses on “Distinguishing the Use of Back Adhesive/Edge Adhesive” from a different angle. Please determine whether the project is approved as NEW. ）*