A polyalkylene glycol-based compound of formula (1): ##STR00001##
may be one in which R.sup.1 is a monovalent hydrocarbon group having 1 to 32 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 42 ring carbon atoms, a monovalent acyl group having 2 to 32 carbon atoms, or a monovalent oxygen-containing hydrocarbon group having 2 to 32 carbon atoms; R.sup.2 is a monovalent hydrocarbon group having 1 to 32 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 42 ring carbon atoms, a monovalent acyl group having 2 to 32 carbon atoms, a monovalent oxygen-containing hydrocarbon group having 2 to 32 carbon atoms, or a hydrogen atom; R.sup.3 is a divalent hydrocarbon group having 4 carbon atoms; R.sup.4 is a divalent hydrocarbon group having 2 or 3 carbon atoms; m and n are respectively numbers between 1 and 40 and 0 and 20; and m/(m+n)0.5.

A polyalkylene glycol-based compound of formula (1): ##STR00001##
may be one in which R.sup.1 is a monovalent hydrocarbon group having 1 to 32 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 42 ring carbon atoms, a monovalent acyl group having 2 to 32 carbon atoms, or a monovalent oxygen-containing hydrocarbon group having 2 to 32 carbon atoms; R.sup.2 is a monovalent hydrocarbon group having 1 to 32 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 42 ring carbon atoms, a monovalent acyl group having 2 to 32 carbon atoms, a monovalent oxygen-containing hydrocarbon group having 2 to 32 carbon atoms, or a hydrogen atom; R.sup.3 is a divalent hydrocarbon group having 4 carbon atoms; R.sup.4 is a divalent hydrocarbon group having 2 or 3 carbon atoms; m and n are respectively numbers between 1 and 40 and 0 and 20; and m/(m+n)0.5.

A polyalkylene glycol-based compound of formula (1): ##STR00001##
may be one in which R.sup.1 is a monovalent hydrocarbon group having 1 to 32 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 42 ring carbon atoms, a monovalent acyl group having 2 to 32 carbon atoms, or a monovalent oxygen-containing hydrocarbon group having 2 to 32 carbon atoms; R.sup.2 is a monovalent hydrocarbon group having 1 to 32 carbon atoms, a monovalent aromatic hydrocarbon group having 6 to 42 ring carbon atoms, a monovalent acyl group having 2 to 32 carbon atoms, a monovalent oxygen-containing hydrocarbon group having 2 to 32 carbon atoms, or a hydrogen atom; R.sup.3 is a divalent hydrocarbon group having 4 carbon atoms; R.sup.4 is a divalent hydrocarbon group having 2 or 3 carbon atoms; m and n are respectively numbers between 1 and 40 and 0 and 20; and m/(m+n)0.5.