Hi Jozef,
If you want a longevity of 10 to 20 years for display purposes, you might need to reconsider the presentation.
If you are printing on a quality paper with pigment inks, the photos probably won't fade in that time, and, provided no one touches the photos, they
might last without glass in front for that long. But, the oils carried by fingers attract dust and dirt in the air and will cause degradation. It's not that people run up to photos and touch them, but as they are pointing to something in the photo, they might inadvertently touch the image. Also, photos need protection from those tactile people who simply must touch to believe!
The glue and substrate of the Kapafix are another issue. You may have better luck finding out more by posting on a European forum since most of the links for Kapafix are European in origin.
The best alternative - wood or metal frames with an archival overmat (to separate the photo from the glass) and glass or acrylic (e.g. plexiglas). For maximum longevity, the photo should not be mounted, but rather taped using hinging/hanging tape available from an art store. There are many web pages dedicated to conservation framing so I'll leave it at that.
One other alternative that is along the lines of what you've described is a product here in North America called "Plak-It" where photos are adhered to a particle board sheet then laminated. See
Plak-It.