| abstract |
It contains one or more of the phosphoric acid esters represented by the following general formula (1), and the total content of the phosphoric acid esters of n = 1, 2, 3, 4 and 5 in the phosphoric acid ester is 99 mass by mass. % Or more and 100% by mass or less, and the content of the phosphoric acid ester represented by the following general formula (1) of n = 1 in the total amount of the phosphoric acid ester is 60% by mass or more and less than 70% by mass. Ester composition. (In formula (1), R 1 and R 2 independently represent a hydrogen atom or a methyl group, respectively. n represents a number of 1, 2, 3, 4, 5, 6 or 7. ) |