1. A composition for forming protective films against aqueous hydrogen peroxide solutions, the composition comprising:a compound of the following formula (1a),

a compound of the following formula (1b), or

a compound of the following formula (2a-1) or

a compound having a substituent of the following formula (2) and having a molecular weight of 300 or more and less than 800 or a weight-average molecular weight of 300 or more and less than 800:

in which R1 is a C1-4 alkylene or alkenylene group or a direct bond, k is 0 or 1, m is an integer of 1 to 3, and n is an integer of 2 to 4; anda solvent; whereinthe composition contains 0.1% by mass to 60% by mass of the compound of the formula (1a) or 0.1% by mass to 60% by mass of the compound of the formula (1b), relative to solids excluding the solvent, or

the composition contains 10% by mass to 100% by mass of the compound of the formula (2a-1) or 10% by mass to 100% by mass of the compound of the compound having the substituent of the formula (2), relative to solids excluding the solvent;

the compound of the formula (1a) is a compound selected from the group consisting of formula (1a-2), formula (1a-3), formula (1a-4), formula (1a-5), formula (1a-6), formula (1a-7), formula (1a-8), formula (1a-9), formula (1a-11), formula (1a-12), formula (1a-13), formula (1a-14), formula (1a-15), formula (1a-16) and formula (1a-18):

the compound of the formula (1b) is a compound selected from the group consisting of formula (1b-1), formula (1b-2), formula (1b-3), formula (1b-4), formula (1b-6), formula (1b-7), formula (1b-8), formula (1b-9), formula (1b-10), formula (1b-11), formula (1b-12), formula (1b-13), formula (1b-14), formula (1b-15), formula (1b-16), formula (1b-17), formula (1b-18), formula (1b-19), formula (1b-20), formula (1b-21), formula (1b-22), formula (1b-23), formula (1b-24), formula (1b-25), formula (1b-26), formula (1b-27), formula (1b-28), formula (1b-29), and formula (1b-30):

the substituent of the formula (2) is a substituent selected from the group consisting of formula (2-3), formula (2-5), formula (2-6), formula (2-7), formula (2-8), formula (2-9), formula (2-10), formula (2-11), formula (2-12), formula (2-13) and formula (2-14):