Japanese folded 4 page sections are folded on the front (front side), this fold remains intact, and the front is not cut. Japenese paperbound books are always perfect bind. The gathered sections of the book are milled at the open spine side and are glued in the cover by means of PUR-glue. PUR-glue is the strongest glue there is. Unlike hotmelt, PUR-glue cannot be melted again after it hardens. By adding a substance (catalyst) to the hotmelt it has become, after hardening, PUR and because of this it glues excellently.
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- With PUR-glue heavier paper types, different paper types together, calco, laminated paper, etc. can be glued together.
- PUR-glue is insensitive to temperature and solvents. For the required specifications see perfect bind cold glue.
- Long life span.
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- The time needed for the PUR to harden can vary from 4 hours up to 3 days, depending on the humidity and the RV of the paper. PUR-glue needs moist for the hardening process.
- Moderate lay-flat. For a better lay-open, cold glue spine gluing is a solution. ( For the required specifications see perfect bind cold glue.)
- More expensive than normal paperbound in perfect bind PUR.
SPINE GLUING
PUR
SPINE THICKNESS
From 2 to 60 mm
SIDE GLUING
Hotmelt till about 5 mm
GRAIN DIRECTION
Parallel to the spine
PAPER KIND BOOK BLOCK
From 60 to 300 gm²
