Can’t the hardcover book cover stick to the book shell after being covered with film? Thoroughly solve 3 key parameter adjustments

The common problem is that the film cover cannot stick to the book cover

After the surface of the hardcover book cover (waist cover/outer cover) is coated with film, the surface energy of the film layer is extremely low,hot melt adhesive pelletsDifficult to wet and penetrate, resulting in weak adhesion between the protective cover and the book case, and detachment during transportation. This is one of the most headache inducing problems for fine decoration factories, but it can be completely solved by adjusting three key parameters.

Three key parameters

• 1. Increase the adhesive temperature by 5-10 ° CThe wettability of the coated surface is poor. Increasing the coating temperature appropriately can reduce the viscosity of the adhesive solution and increase the spreading area. It is recommended to raise the temperature of the backing adhesive to 175-185 ° C, but not exceed 190 ° C to prevent aging of the adhesive solution.
• 2. Increase the amount of glue by 20-30%The standard adhesive content is 80-100g/m ², and it is recommended to increase the coating surface to 100-130g/m ². An increase in adhesive content can compensate for the decrease in contact area caused by insufficient wetting.
• 3. Extend the pressing time by 3-5 secondsThe heat dissipation of the laminated surface is slow, and the cooling and curing speed of the adhesive solution is slower than that of the bare paper surface. Extend the pressing time to ensure sufficient wetting and initial curing of the adhesive layer.

The above adjustments, combined with Sunlife’s high initial adhesion model of hot melt adhesive particles, can achieve a bonding strength of over 85% of the bare paper surface.

Frequently Asked Questions (FAQ)

Q: Does the type of film coating (light film/matte film) have an impact on adhesion?

A: Yes, there is. BOPP film has the lowest surface energy and is the most difficult to stick, while matte film is slightly better. It is recommended to use high initial adhesion type and primer for light film sealing.

Q: Can cold glue be used for film covering?

A: Cold glue is also difficult to wet on the coated surface, and slow curing affects efficiency. Hot melt adhesive particles with high temperature and low viscosity are a better choice for wetting.