C.P.Bourg BB3002 PUR, Operator'S Manual

Page: 17 / 142

Operator Manual
BB3002 Page 17
Initial issue: 05/08
Latest revision: 11/08
1 .6 What is PUR?
PUR (polyurethane) is a reactive hot melt material that is melted and processed like
conventional hot melt adhesive. It binds in a hot–cold process and cross-links under the
influence of moisture, thus achieving its final solidity.
The original plastic film thus becomes elastic and very flexible, and it can no longer be
melted or dissolved. It is temperature resistant from -30 °C (-22°F) to +150 °C (302 °F)
and is resistant to chemicals.
1 .7 Working with PUR
• The durability of a product bound with PUR can not be evaluated when it first leaves
the binding machine. But when the cover and the edges of the pages show sufficient
adhesive (film strength 0.4 to 0.5 mm), it can safely be assumed that the pull value
after cross-linking is very good.
• The bound products should be handled very carefully within the first 24 hours, even
after stacking. Avoid mechanical force.
• Pull value measurements after 6 hours show approx. 1/3 of the final value to be
achieved. This value depends strongly on the paper and the ambient humidity.
• The maximum pull value is achieved after 24 hours.
• Books that are opened all the way to the inside margin within 24 hours of binding are
no longer suitable for sale.
• Material in opened drums can no longer be used when it has come into contact with
ambient humidity for even a few hours. Thus drums should be emptied completely
(light tower: yellow light on). Lubricate heating punch sealing ring every time the drum
is changed.
• Slugs (for PUR C) must be put in the Melter tank immediately after the opening of the
pack.
• If the system is not used for 5 days, it must be purged with a cleaning agent.
• Observe instructions of adhesive/cleaning agent supplier!