Problems needing to be solved in the research of Ink

- Nov 08, 2017-

1 so that the product can be written at any time after the good rub, wipe the blackboard will not remain traces. Even if you just write a good word immediately can easily erase, even after one months, still easy to wipe.

2 Write the color does not change shallow darken, overcome the whiteness is not good and can not be used in the classroom behind the students see the shortcomings.

The whiteness problem is crucial, which is related to the practical importance of liquid chalk.