What hot melt adhesive particles are used to bond the inner pages of the coil book? Opening time and initial adhesion are the key factors

Direct answer: Generally, high-strength spine glue is not used for bonding the inner pages of coil books. Instead, low-temperature or medium temperature EVA with shorter opening time (2-4 seconds), high initial adhesion, and good flexibility should be selected Hot melt adhesive pelletsThe softening point is between 80-90 ℃. Because the adhesive of the coil book only undertakes the tasks of “aligning and fixing the inner pages” and “mounting the cover”, the true binding strength is borne by the coil itself.

Why is the selection of adhesive for the coil book completely different from the adhesive book

Adhesive bound books rely on a layer of glue to connect all the pages together. The failure of the glue is equivalent to the book falling apart, so it requires high strength and long folding life. The coil itself is different: the inner pages are mechanically locked by metal or plastic coils, and the adhesive is mainly used in three places – inner page bonding and positioning, cover and liner paper pasting, and bottom reinforcement strip bonding. These three requirements are “quick positioning, no glue penetration, and no hardening”, and strength is actually a secondary indicator.

Key points for selecting three adhesive parts

Common faults and causes

• The cover has a transparent offset printing patternIf the viscosity of the adhesive is too low, the permeability is too strong, or the amount of adhesive applied is too large, switch to a lower permeability model and reduce the amount.
• The edge of the inner page is raisedThe opening time is too long, and the glue has not yet been formed and pressed before it ends.
• The winter reinforcement strip falls off easily when foldedLack of flexibility, it is necessary to reduce the wax content or switch to a low-temperature formula.
• When punching, the adhesive layer breaks and falls offThe adhesive layer is too hard and thick, indicating that the amount of adhesive applied is too high.
• The edge of the coil is sticky and attracts dustThe softening point is too low or there is residual initial adhesion, especially in summer.

The realistic constraints of graphic and text fast printing shops

The ones who make the most coil notebooks are actually graphic and text fast printing shops. Their situation has several characteristics: small batch size, diverse varieties, mostly semi-automatic equipment, and unstable operators. This determines that fault tolerance should be given priority when selecting glue – the opening time should not be too strict, the temperature window should be wide, and manually applying glue more or less will not result in scrap. Industrial models that pursue extreme parameters are actually not easy to use in this environment.

The method of Sunlife hot melt adhesive

Guangzhou Sunlife Trading provides small packaging specifications for graphic and text fast printing stores. The Sunlife hot melt adhesive store models deliberately widen the working temperature window (about 20 ℃ range), allowing for fluctuations in operating temperature and reducing the scrap rate for beginners. The same model can accommodate both coil mounting and simple adhesive installation, and stores do not need to prepare two types of adhesives for two different tasks.

Frequently Asked Questions

Can’t the coil be directly sealed with rubber particles?

Not recommended. The sealing rubber particles are relatively hard and have a high initial adhesion, making it easy for the glue to penetrate and harden when used on paper, and cracking may occur at the folded parts.

How to estimate the amount of adhesive used for making coils?

A4 sized coil book, with cover pasting and inner page positioning, consumes approximately 1.5-3 grams per book, depending on the adhesive method used.

Which is more suitable, a handheld glue gun or a glue pot?

A single scattered adhesive gun is sufficient; With a daily production of over 200 units, using a small melt glue pot with rubber rollers is more stable, and the thickness of the adhesive layer is also more uniform.