Expansion envelope

Expansion envelopes are complicated to produce (especially in terms of gluing), therefore in this case we cannot offer a full range of formats and proportions. We neither make envelopes thinner than 20 mm nor smaller than A5-format size. The raw material most commonly chosen for this product to be made of is 130-170 g/m2 paper. While some archivists prefer paperboard from the 240-300 g/m2 range, it is worth noting that such solutions are quite costly and more difficult to apply. The flaps of expansion envelopes are longer that those of standard envelopes and should be slid inside the enclosure in order to attain better sealing quality. 

Please note: when placing an order for envelopes, make sure you provide us with their inner dimensions which take into account a safety margin added to the format of an object to be stored.

We use a high quality EVA adhesive to produce our envelopes. 

• Papier:
  - certyfikat ISO 9706 oraz atest PAT
  - 100% celulozy
  - kolor: biały
  - rezerwa alkaliczna > 0,4 mol/kg
  - liczba Kappa < 5
  - gramatura: 170 g/m2
• Klej:
  - wartość pH 7.0 – 8.0
  - bez zmiękczaczy
  - klej na bazie kopolimeru etylenu i octanu winylu EVA