Patent ID: 8003117

Claim:
A polyalkylene glycol derivative comprising a compound of the formula (1): wherein R is a hydrocarbon group having 1 to 24 carbon atoms, OA 2 is an oxyalkylene group having 2 to 4 carbon atoms, the groups represented by R are the same or different from each other in one molecule, the groups represented by OA 2 are the same or different from each other in one molecule, m is an average number of moles of the above oxyalkylene group added, m represents 10 to 1000, and X represents a functional group capable of covalently bonding with a residual group selected from the group consisting of an amino group, a mercapto group, an unsaturated bond, a carboxyl and an aldehyde group of a bio-related substance, and polydispersity Mw/Mn of the polyalkylene glycol derivative in gel permeation chromatography satisfying the following relationship: Mw/Mn≦1.07 wherein Mw represents a weight average molecular weight and Mn represents a number average molecular weight, and wherein X is a group selected from the group (I): Group (I) wherein W 1 is a halogen atom selected from Cl, Br, and I; and wherein Z is a structure selected from the following structures (z1) to (z8): wherein s is an integer of 1 to 6.