What kind of paper is the 'impregnated paper' mentioned in the craft file description?
This question is asked when wondering if a paper file inserted into a notebook will tear easily, or wanting to know what the unfamiliar term 'impregnated paper' written in the description means.
Impregnated paper is paper processed to be tough and durable by having resin components permeate the paper fibers, characterized by not tearing easily even when items are frequently inserted and removed.
Impregnated paper refers to processed paper made by having components such as resin deeply permeate into the interior of paper fibers during the manufacturing process. By undergoing a method of soaking in a liquid substance and curing it, the bonds between fibers become strong, giving it the characteristic of being tougher than ordinary paper and holding up well against moisture or friction.
TRAVELER'S COMPANY used this impregnated paper, namely Saturating Paper, as the material for the craft file refill inserted into the Regular size notebook[1][2]. Measuring 222mm wide and 210mm high, this file consists of 2 pockets on the inside where notes or receipts can be stored[3][4].
Files where tickets or postcards are frequently inserted and taken out often experience friction at the folds and pocket openings, making the corners prone to fraying first. While maintaining the distinctive texture of kraft paper, durability has been supplemented so that the pocket shape does not easily fray even when repeatedly opening and closing the notebook inside a bag.
hmmm, just like the leather cover on the outside, the underlying foundation of the paper inside was firmly chosen unseen so that the interior file can also withstand handling over a long time.

The specific thickness of the impregnated paper used in the craft file or the type of processing components permeated into the paper have not yet been confirmed.