Why does the eraser "eat" plastic when left together?

When you were in school, you must have shared many learning tools such as rulers, pens, erasers, and calculators. Then after the summer break “away from the face, from the heart”, when you need to use it, you will be shocked when you see that the computer and the plastic ruler are all deformed. Of course, at that time, you only know how to get angry because the weather is too hot to make things melt, or suspect that someone has played bad with glue on your things.

Notably, this strange phenomenon is quite common when many Vietnamese and international netizens have encountered it when they were still in school. The topic quickly attracted a lot of discussion on the social network Reddit and on Facebook groups. They all share the same question, ” what magic is this?”

Why does the eraser "eat" plastic when left together?
The question was posed by a Redditor on the MXH Reddit about the strange phenomenon.

In fact, there was no magic here at all, and the “unsub” was present at the scene at that time. As it turns out, this is actually an interesting scientific phenomenon, which is caused by a type of compound found in bleach known as a “plasticizer”. They are substances added to the material to increase the flexibility of the eraser, making the eraser not hard, crumbly and easier to use.

Why does the eraser "eat" plastic when left together?
Many Vietnamese netizens also encountered this case.

According to Wikipedia, plasticizers are used extensively when machining polymeric materials. The plasticizer content is usually 20-30%. Plasticizers are usually esters of organic compounds such as DBP – dibutyl Phthalate, DOP – dioctyl phthalate, DIOP – diizooctyl phthalate… Plasticizers reduce the vitrification and melting temperature of polymers. It reduces the stiffness but increases the durability and toughness of the material.

Therefore, when the eraser is placed near other plastic materials, the plasticizer in the eraser will “eat” or melt those materials. You can check by placing the eraser next to an elastic band, after only 2 days the elastic will be just a twisted plastic ball. And of course, there’s no magic here.

So, don’t blame the weather anymore, but wrap your erasers more carefully or separate them.