Monday, 15 June 2015

What is ...PUR Binding?

What is ...Number 18
Regular followers of this blog will know that in the middle of the month, I publish a "What is ....? post. The article covers various aspects of paper, printing and finishing in greater depth. However, many of these subjects are complex, so these posts are only intended to be a brief introduction to the topic.

What is ...PUR Binding?
Brochures, paperback books, hardcover books and magazines with a sqaureback and a thickness greater than around 5mm will be bound using either glue (perfect bound) or thread and glue (section sewn). In the early 1990's a new development in adhesive technology changed the strength and therefore the reputation of perfect binding forever.

Section sewn binding has been around since books were first produced - using different types of glue as times changed. Section sewn binding is still regarded as the best and strongest as it relies on both thread and glue. Perfect Binding (glue only) has always been regarded as weaker and less durable (...remember all those magazines and paperbacks where pages have fallen out?)

In the early 1990's, a new type of adhesive was developed. This adhesive is called Polyurethane Reactive Hotmelt and is known as PUR. As the name hotmelt suggests, the glue is heated and applied hot. This new adhesive involves a chemical reaction between the glue and moisture in the atmosphere and paper to give a much greater strength and flexibility than using normal glue. The finished bound books reach their optimum strength 24 hours after binding.

There was a bindery close to us called Tonbridge Trade Binders (TTB) which was the first bindery in the UK to install the tanks to handle PUR glue on their binding line, this was around 1995. Unfortunately TTB closed down about ten years ago but many trade binders now have PUR systems.
PUR binding is very strong but one of the limitations in the early days was that it was only suitable for longer runs, which I believe was to do with the time it took to set up the machinery, these days that isn't the case and there are PUR machines that can do small runs.
...for example, below is an image of the BB3002 PUR binding line by CP Bourg, a machinery manufacturer based in Belgium. It's representative of the relatively small machines now available, many of which are being installed by printers in house.
Today PUR binding is highly regarded and is many customer's preferred binding method.

Posted by Justin Hobson 15.06.2015

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Thanks for your comment! If I like it, I'll add it on. Cheers J