First, my seventh grade English teacher insisted that we never use the word "this" without stating what "this" is. Doing so helps the reader understand more fully what the writer is trying to convey.
Second, you can simplify the sentence by eliminating "will have to be".
I don't understand the meaning of the phrases minimum weight fraction and volume fraction. Unless these are technical terms that you and your audience are familiar with, I suggest that you say it in another way.
eg something like . . . minimum percentage of the total weight . . . ?