Hi ya All. So what do door manufactures use? I have never heard of fire-proof glue either.......but whatever glue is used by manufactures, it must be part of passing the fire integrity tests so the question is valid and worth checking.
Some glues may in fact not react to heat or fire. If they did not, the face skin veneers would delaminate and slide down off the door core so what does happens to a fire door? What bonds the various layers and laminations? It isn't’ PVA.
I think urea formaldehyde adhesives are used by door manufactures. Possibly also the variations of which I know little, i.e. melamine-formaldehyde., etc. I think a more technical term may be, Fire Resistant Adhesives, Fire Retardant Adhesives, or High temperature resistant adhesives, so they are definitely around for industrial use. I do know it is possible to purchase the odd tube of special high temperature sealants but don’t know where you would get small quantities of ‘fire proof glues’. Adhesives are around that will withstand 200-600deg F. but I think your dead long before that temperature is reached. Epoxy resin adhesives may also be used in door production.
The steel/aluminium sandwiched roof and wall insulated panels must use a fire resistant adhesive of some sort as they are also fire rated, partly due to the levels of insulation but they must retain integrity in a structure in fire. They couldn’t delaminate. Aircraft are glued together nowadays so probably fire resistant. Years ago I used adhesive tapes from the aircraft industry to glue shop cornice panels together, sounds a bit like over kill now but it was a super duper job.
It is what is practical for the question and if the requirement is relevant and not ‘over kill by the client’. Depends upon what is being fixed, but there are 'fire' glues there to use. It may be you will need to purchase a 5,000 gal. road tanker of the stuff.
Terms are relative; like ‘non-slip’ floor coverings are actually ‘slip-resistant’ and so ‘fire-resistant’ rather than ‘fire-proof’.
There you are. Good luck.