Please note that MR (Moisture resistant) is of a lesser quality and cost compared to BWR grade. While it true that MR plywood can resist a certain degree of moisture and humidity, it certainly cannot be called waterproof. On the other hand, BWR plywood is a waterproof plywood.
MR is an interior grade plywood useful for making indoor furniture (office furniture, furniture where there is less application of water or moisture) while BWR plywood is exterior grade(places like kitchen, bathroom doors, furniture below water tanks or any spot where the surface is directly exposed to sunlight and water .
BWR – Phenol formaldehyde synthetic is used for glueing the plies together. This is a synthetic plastic resin.
MR – Urea formaldehyde resin is used for bonding the plies to each other. UF resin is not considered to be very eco-friendly.