Hotmelt Book Adhesive Is Heat Resistant

Sovereign Specialty Chemicals have developed Primamelt 37-300, a hotmelt adhesive for book spine applications.

Sovereign Specialty Chemicals have developed Primamelt 37-300, a hotmelt adhesive for book spine applications.

It is claimed to bridge the gap between the standard high wax content EVA hotmelts that comprise the majority of the current market and the much more expensive high-performance reactive polyurethane (PUR) adhesives used on high quality magazines and catalogues and heavily coated paper stocks.

According to Sovereign, PUR adhesives perform well on difficult heavily coated papers and have excellent temperature resistance but they are very expensive, require special equipment to apply and are virtually unroundable.

In most cases binding speeds are reduced too.

Current EVA hotmelts are cheap and the high wax content makes them quick setting, which is ideal for modern high speed book production lines.

The wax content reduces the adhesion of the adhesive, however, so a thick glue line is applied to clamp the spine solidly.

Unfortunately, the wax makes the finished book susceptible to changes in temperature and climate.

In cold conditions the book can be difficult to open and in a hot climate or during a hot summer the clamping effect is markedly reduced and pages can fall out of the book added the company.

The new adhesive, Primamelt 37-300, has been formulated using new polymers to produce a flexible, ink distillate resistant glue line that has high heat resistance.

The film produced is tough and can be applied with a relatively low coat weight, so material savings of as much as 50 per cent compared to the high wax content EVA types are possible.

Because the film is thermoplastic, it is much easier to 'round' than a PUR, yet has excellent adhesion to the paper fibres claimed Sovereign.

The company added that Primamelt 37-300 is designed to run on high speed, binding lines using standard roller application equipment.

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