Abstract: The present invention provides a water-soluble film which comprises a modified polyvinyl alcohol containing an N-vinylamide monomer unit in an amount of 1 to 10 mole percent, and a carboxyl group and a lactone group in a total amount of 0.020 to 4.0 mole percent in the molecule, and having a degree of polymerization of 300 to 3000, and a degree of hydrolysis of 75 to 99.5 mole percent. Further, the present invention provides a package obtained by packaging an acidic substance, a chlorine-containing compound, or the like using the water-soluble film.

Abstract: A water-soluble resin composition is provided which comprises (i) 100 parts by weight of a polyvinyl alcohol polymer having a 1,2-glycol linkage content of at least 1.8 mole percent and a degree of hydrolysis of at least 90 mole percent, (ii) 1 to 50 parts by weight of a plasticizer and (iii) 5 to 50 parts by weight of a monosaccharide and/or a polysaccharide, optionally together with (iv) 1 to 20 parts by weight of an inorganic filler. Also provided is a water-soluble resin composition which comprise (i′) 100 parts by weight of a polyvinyl alcohol polymer having a 1,2-glycol linkage content of at least 1.8 mole percent and a degree of hydrolysis of 92 to 99 mole percent, (ii′) 1 to 50 parts by weight of a plasticizer and (iv′) 1 to 20 parts by weight of an inorganic filler, optionally together with (iii′) 5 to 50 parts by weight of a monosaccharide and/or polysaccharide. Further provided are water-soluble films produced by using those water-soluble resin compositions.

Abstract: The present invention provides a polarizing film having a dichroic ratio of at least 20 and comprising a polyvinyl alcohol derivative with a polyvinylene structure as obtained from a polyvinyl alcohol material having a degree of polymerization of at least 2000. The polarizing film of the present invention has excellent polarizing properties in the range of the visible ray spectrum, and exhibits excellent durability when left in high-temperature and high-humidity surroundings for a long period of time. The polarizing film of the present invention is useful for a polarizing sheet laminated with a protective film for on-vehicle LCD that is placed in heavy temperature and humidity fluctuations, such as LCD navigation systems, LCD TV, etc.

Abstract: Difference in retardation between two points separated by 1 cm along the TD direction of a polyvinyl alcohol polymer film 6 is 5 nm or less. The length of a surface for drying a polyvinyl alcohol polymer film 6 is 3 m to 200 m, and the water content of the polyvinyl alcohol polymer film 6 when peeled after passing through the drying surface is 50% by weight or less, in film formation.

Abstract: A polyvinyl alcohol polymer film in which the amount of a polyvinyl alcohol polymer eluted when a 10 cm square polyvinyl alcohol polymer film is left in 1 liter of water of 50° C. for 4 hours is from 1 to 100 ppm. A polyvinyl alcohol film in which the content of an alkali metal compound is 0.5% by weight or less based on the polyvinyl alcohol. Further, a polarization film produced by using the same.