Water-soluble film and package
[Problem to be solved] To provide a water-soluble film having good transparency and good releasability from a support with less surfactant content. [Solution] A water-soluble film containing a polyvinyl alcohol resin and surfactant, wherein a content of the surfactant is 0.005 to 1 parts by mass with respect to 100 parts by mass of the polyvinyl alcohol resin, and a ratio S(0)/S(32) of an abundance amount S(0) of the surfactant on at least one surface of the water-soluble film to an abundance amount S(32) of the surfactant on a cross-section surface at a depth of 32 nm from the at least one surface of the water-soluble film, measured by a count number of fragment ions derived from the surfactant detected by time-of-flight secondary ion mass spectrometry on the at least one surface of the water-soluble film, is in the range of 100 to 500.
1 . A water-soluble film containing a polyvinyl alcohol resin and surfactant,
wherein a content of the surfactant is 0.005 to 1 parts by mass with respect to 100 parts by mass of the polyvinyl alcohol resin, and a ratio S(0)/S(32) of an abundance amount S(0) of the surfactant on at least one surface of the water-soluble film to an abundance amount S(32) of the surfactant on a cross-section surface at a depth of 32 nm from the at least one surface of the water-soluble film, measured by a count number of fragment ions derived from the surfactant detected by time-of-flight secondary ion mass spectrometry on the at least one surface of the water-soluble film, is in the range of 100 to 500.
2 . The water-soluble film as claimed in claim 1 , wherein the surfactant is a nitrogen-containing surfactant.
3 . The water-soluble film as claimed in claim 2 , wherein the nitrogen-containing surfactant contains at least one selected from the group consisting of an alkylamine-based surfactant, an alkylamide-based surfactant and an alkylalkanolamide-based surfactant.
4 . The water-soluble film as claimed in claim 3 , wherein the alkylamine-based surfactant is a polyoxyethylene alkylamine-based surfactant, and the alkylamide-based surfactant is a higher fatty acid diethanolamide-based surfactant.
5 . The water-soluble film as claimed in claim 1 containing a filler.
6 . The water-soluble film as claimed in claim 5 , wherein the filler is inorganic particles.
7 . A package in which the water-soluble film as claimed in claim 1 stores a chemical.
8 . The package as claimed in claim 7 , wherein the chemical is a pesticide, a detergent or a disinfectant.
9 . The package as claimed in claim 7 , wherein the chemical is in a liquid form.
10 . The water-soluble film as claimed in claim 1 , wherein the polyvinyl alcohol resin excludes a copolymer of vinyl ester-based monomer and an allyl compound.
11 . The water-soluble film as claimed in claim 1 , wherein the polyvinyl alcohol resin comprises a methyl maleate (MA)-modified polyvinyl alcohol resin.
12 . The water-soluble film as claimed in claim 1 , wherein the water-soluble film excludes starch.
13 . The water-soluble film as claimed in claim 5 , wherein the filler is selected from the group consisting of clay, talc, alumina, and acrylic resin fine particles.
14 . The water-soluble film as claimed in claim 1 , wherein the surfactant comprises polyoxyethylene laurylamine.
15 . The water-soluble film as claimed in claim 1 , wherein the surfactant comprises lauric acid diethanolamide.