Modifying agent for polyolefin resin films, composition for polyolefin resin films, modified polyolefin resin film, and multilayer film

A resin composition for a polyolefin resin film, comprising 0.1% to 30% by mass of a modifying agent for a polyolefin resin film and 99.9% to 70% by mass of a polyolefin resin, wherein the modifying agent is a partial ester of diglycerol with a straight chain aliphatic carboxylic acid having 8 to 22 carbon atoms, the partial ester contains 70% by mass or more in total of monoester and diester, and the mass ratio of the content of the monoester to the content of the diester is monoester/diester=30/70 to 86/14.

A modified polyolefin resin film, comprising 0.1% to 5% by mass of a modifying agent for a polyolefin resin film, wherein

• the modifying agent is a partial ester of diglycerol with a straight chain aliphatic carboxylic acid having 8 to 22 carbon atoms, the partial ester contains 70% by mass or more in total of monoester and diester, and the mass ratio of the content of the monoester to the content of the diester is monoester/diester=30/70 to 86/14, and
• in the film, the content of a diethanolamine compound having an alkyl group or alkenyl group having 8 to 22 carbon atoms or a diethanolamide compound having an alkyl group or alkenyl group having 8 to 22 carbon atoms is 0.02% by mass or lower, and the content of an alkylsulfonic acid alkali metal salt is 0.004% by mass or lower.

A laminated film, comprising a modified polyolefin resin film layer that contains a modifying agent for a polyolefin resin film as at least either one surface layer thereof, wherein

• the modifying agent is a partial ester of diglycerol with a straight chain aliphatic carboxylic acid having 8 to 22 carbon atoms, the partial ester contains 70% by mass or more in total of monoester and diester, and the mass ratio of the content of the monoester to the content of the diester is monoester/diester=30/70 to 86/14, and
• the laminated film contains 0.01% to 5% by mass of the modifying agent for a polyolefin resin film.

A method of modifying a polyolefin resin film using a modifying agent that is a partial ester of diglycerol with a straight chain aliphatic carboxylic acid having 8 to 22 carbon atoms, wherein the partial ester contains 70% by mass or more in total of monoester and diester, the mass ratio of the content of the monoester to the content of the diester is monoester/diester=40/60 to 86/14,

• wherein the polyolefin resin film is substantially free of a diethanolamine compound having an alkyl group or alkenyl group having 8 to 22 carbon atoms or a diethanolamide compound having an alkyl group or alkenyl group having 8 to 22 carbon atoms and an alkylsulfonic acid alkali metal salt, the polyolefin resin film being a film for food, and
• wherein the partial ester has a permeation amount of 20 mg/g or larger and an HLB of 2 to 8.5.