Bleach cleanable carpets is some stupid term that the carpet industry has come up with. Bleach resistant carpets were originally designed as an advantage in nursing homes and similar situations where there is a greater risk of bleaching because of the situation. They have been in the contract market for a long time.
It is a pretty silly idea to give somebody the inclination to clean their carpets with chlorinated bleach in the first place. If you cleaned your lounge carpet with bleach then sat down to watch the telly then the fumes present would do you no good at all.
Bleach resistant should never have been rephrased into bleach cleanable. Just another of the generally used but totally misleading terms.
With regards to cleaning polypropylene the fibre is very resistant to chemicals. The problem lies with natural backed carpets as any moisture will run down the fibre into the backing giving the possibility for schrinkage, as is the case with poly propylene wiltons.
Belgium wilton is an inaccurate description used by many, as the belgiums make wiltons with other fibre pile and they are not the only country using polypropylene in wiltons.
The majority of polypropylene wiltons encountered will be Belgium origin but not all.
Peter