To distinguish between UMC and MMC, let's see what they have inside.
UMC, also called A1, 30% melamine, is one of the class of synthetic resin obtained by urea formaldehyde, cellulose filler and other additives. And MMC, also called A5, 100% melamine, is one of the class of synthetic resin obtained by melamine formaldehyde, cellulose filler and other additives. MMC is very similar to UMC in its processing and application. But MMC are more moisture-resistant, harder, stronger and safer to use. Its generall effect is porcelain-like. So in 1950s, MMC start to replace UMC as one of main molding material for plastic tableware.
It is a cliche to say that the direction depends on your local market. If the local market favors low price product, then choose UMC, and if prefer quality then MMC. But one thing needs to be notice is that, as a country's economy grows, it is inevitable for its people to focus more on their quality of life. So UMC will be less likely to be the choice. For example, China has already prohibited UMC as the material to produce the food containers since 2009, when its economy was developed at very fast speed.
In conclusion, if your local market prefer cost of the product, choose UMC, if it emphasizes more on quality, then MMC. But for those contries, whose economy is growing fast, better prepare more for MMC.
