This compound (known as MCI for short) is a common preservative
found in most 'rinse-off' products (IE: short skin
exposure). However, it can apparently also be found in many cosmetics (foundation
etc). It's called Kathon in industry, where it's used as a preservative in cutting fluids(!).
Okay, so most of this was stolen from the web - but it does seem to be remarkably similar (chemically) to anilinethiazolinones(ATZ). These are formed by the Edmann degradation reaction to sequence proteins. Which would mean that a methylchloro-TZ is just the MeCl derivative of one of these compounds (a hetrocyclic pentameric ring).
Presumably, 'preservative' means antimicrobial/antifungal agent. So it's basically an antibiotic.