is relatively a new term as it refers to bookbinding. Actually, PUR
is a hot melt adhesive similar to EVA hot melts, but the adhesive
is manufactured with polyurethene reactive material (PUR). As the
adhesive product dries a natural chemical reaction occurs after the
glue is exposed to moisture in the air. The results of the chemical
reaction creates a superior bond within the fibers of the paper giving
the book a greater pull and flex strength. In most but not all product
situations the books are more durable and lay flatter when opened
than a typical EVA adhesive product. The disadvantages of this adhesive
are that the cure time requires that the books not be used for almost
24 hours after application and the cost is slightly higher. Care should
be taken when selecting this type of binding because in many instances
the finished product does not require the additional cost associated
with the application process.
Tips for Best
PUR Binding Results:
Allow a minimum 1/8" head, tail and face trim on inside
Allow 1/16" to 1/8" for "grind" on
spine edge of inside text pages.
On the cover, leave an extra 1/8" at the head and
an extra 1/4" at the tail of the untrimmed folded signatures.