At Flexpress, we like to produce the very best perfect bound book we can for our clients, which is why we’ve now upgraded to PUR glue (Polyurethane Reactive) .
Whilst traditional EVA (Ethylene Vinyl Acetate) glue is fine for many applications, there is no question PUR offers many advantages from a user’s perspective.
- The spine can be folded and the book opened flat without the risk of pages falling out.
- There is more resistance to page pull-out; in fact there is more chance of the paper ripping than the page pulling out.
- PUR provides superior adhesion to a wider range of substrates including coated and thicker grades.
- EVA glue can suffer from softening in extremely warm climates and g brittle in extreme cold. PUR remains stable at all extremes.
- Because less glue is needed, there is less distortion to the spine
So why doesn’t everyone use PUR? If everyone had the clients best interest at heart, they probably would! But it does have disadvantages, mainly from a production perspective. Firstly there is more ‘housework’. Every day, every part of the machine that’s had contact with the glue needs to be cleaned thoroughly. When melted, PUR glue can’t be re-melted whereas EVA can be melted, hardened and remelted time and time again. Plus, unlike EVA glue, PUR doesn’t cure instantly. It takes 8 hours to fully cure meaning books can’t be opened before this deadline.
We feel the advantages for our clients far outweigh the disadvantages for us, so are now offering PUR as standard on all our perfect bound books. We know that once you’ve tried it, you’ll be a PUR convert, just like us!