A soft magnetic material powder includes soft magnetic material particles, the soft magnetic material particles each include a core formed from an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer. A magnetic core includes soft magnetic material particles and a binder bonding the soft magnetic material particles to each other, the soft magnetic material particles each include a core containing an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer.

A soft magnetic material powder includes soft magnetic material particles, the soft magnetic material particles each include a core formed from an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer. A magnetic core includes soft magnetic material particles and a binder bonding the soft magnetic material particles to each other, the soft magnetic material particles each include a core containing an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer.

A soft magnetic material powder includes soft magnetic material particles, the soft magnetic material particles each include a core formed from an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer. A magnetic core includes soft magnetic material particles and a binder bonding the soft magnetic material particles to each other, the soft magnetic material particles each include a core containing an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer.

A soft magnetic material powder includes soft magnetic material particles, the soft magnetic material particles each include a core formed from an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer. A magnetic core includes soft magnetic material particles and a binder bonding the soft magnetic material particles to each other, the soft magnetic material particles each include a core containing an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer.

A soft magnetic material powder includes soft magnetic material particles, the soft magnetic material particles each include a core formed from an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer. A magnetic core includes soft magnetic material particles and a binder bonding the soft magnetic material particles to each other, the soft magnetic material particles each include a core containing an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer.

A soft magnetic material powder includes soft magnetic material particles, the soft magnetic material particles each include a core formed from an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer. A magnetic core includes soft magnetic material particles and a binder bonding the soft magnetic material particles to each other, the soft magnetic material particles each include a core containing an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer.

A soft magnetic material powder includes soft magnetic material particles, the soft magnetic material particles each include a core formed from an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer. A magnetic core includes soft magnetic material particles and a binder bonding the soft magnetic material particles to each other, the soft magnetic material particles each include a core containing an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer.

A soft magnetic material powder includes soft magnetic material particles, the soft magnetic material particles each include a core formed from an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer. A magnetic core includes soft magnetic material particles and a binder bonding the soft magnetic material particles to each other, the soft magnetic material particles each include a core containing an Fe-based soft magnetic material and an insulating film covering the surface of the core, and the insulating film contains an inorganic oxide and a water soluble polymer.

An esterified cellulose ether is provided wherein the ester groups are phthalyl groups, the degree of substitution of phthalyl groups is from 0.02 to 0.18, the degree of neutralization of phthalyl groups is not more than 0.75, and the esterified cellulose ether has a solubility in water of at least 2.0 weight percent at 2 C.

Esterified cellulose ethers which have i) as ester groups aliphatic monovalent acyl groups or groups of the formula C(O)RCOOA or a combination of aliphatic monovalent acyl groups and groups of the formula C(O)RCOOA, wherein R is a divalent aliphatic or aromatic hydrocarbon group and A is hydrogen or a cation, and ii) a content of not more than 0.85 weight percent acetone-insoluble esterified cellulose ether particles, when the esterified cellulose ether is present in a mixture of 12.5 weight parts of esterified cellulose ether and 87.5 weight parts of acetone at 21 C., the weight percent acetone-insoluble esterified cellulose ether particles being based on the total weight of the esterified cellulose ether, wherein iii) not more than 14 percent of the acetone-insoluble esterified cellulose ether particles have a particle size of more than 90 micrometers.