The gathered sections of the book are milled; the single pages brought about by this are glued in the cover by means of PUR, PUR is the strongest glue there is. Unlike hotmelt, PUR cannot be melted again. By adding a substance (catalyst) to the hotmelt, it will become PUR after it hardens.
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- With PUR-glue heavier paper kinds, different paper kinds together, calco, laminated paper, etc. can be glued together.
- PUR-glue is insensitive to temperature and solvents.
- 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.
- About 5% more expensive than paperbound in perfect bind hotmelt.
- Moderate lay-flat.
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
