The present invention relates to ethylene-vinyl alcohol copolymer particles, comprising an ethylene-vinyl alcohol copolymer having an ethylene unit content of 1 mol % or more and less than 20 mol %, a viscosity-average polymerization degree of 200 to 5000, and a saponification degree of 80 to 99.99 mol %, wherein a crystallinity in water Cw (30° C.) at 30° C. and a crystallinity in water Cw (70° C.) at 70° C. as determined by pulse NMR satisfy formula (I). There is thus provided ethylene-vinyl alcohol copolymer particles having excellent solubility in water and excellent gas barrier performance.

A modified vinyl alcohol-based polymer includes a polyoxyalkylene unit, and an organic acid unit bonded to a polyvinyl alcohol chain, the polyoxyalkylene unit includes a moiety represented by the general formula (I), the moiety being bonded to the polyvinyl alcohol chain only via an ether bond and/or a carbon-carbon bond, wherein a ratio of a number of moles of monomer units bonded to the polyoxyalkylene unit to a total number of moles of the monomer units constituting the polyvinyl alcohol chain of the modified vinyl alcohol-based polymer is 0.01 mol % to 5 mol %, and a ratio of a number of moles of the organic acid unit to the total number of moles of the monomer units constituting the polyvinyl alcohol chain of the modified vinyl alcohol-based polymer is 0.1 mol % to 10 mol %.

A modified vinyl alcohol-based polymer includes a polyoxyalkylene unit, and an organic acid unit bonded to a polyvinyl alcohol chain, the polyoxyalkylene unit includes a moiety represented by the general formula (I), the moiety being bonded to the polyvinyl alcohol chain only via an ether bond and/or a carbon-carbon bond, wherein a ratio of a number of moles of monomer units bonded to the polyoxyalkylene unit to a total number of moles of the monomer units constituting the polyvinyl alcohol chain of the modified vinyl alcohol-based polymer is 0.01 mol % to 5 mol %, and a ratio of a number of moles of the organic acid unit to the total number of moles of the monomer units constituting the polyvinyl alcohol chain of the modified vinyl alcohol-based polymer is 0.1 mol % to 10 mol %.

A method for producing a resin having a repeating unit that is decomposed by irradiation of an actinic ray or a radiation to generate acid, the method including polymerizing a specific compound represented by General formula (P-1) and a copolymerizable monomer compound, a method for producing an actinic ray-sensitive or radiation-sensitive resin composition, a pattern forming method, and a resin corresponding to a reaction intermediate of the resin.

A method for producing a resin having a repeating unit that is decomposed by irradiation of an actinic ray or a radiation to generate acid, the method including polymerizing a specific compound represented by General formula (P-1) and a copolymerizable monomer compound, a method for producing an actinic ray-sensitive or radiation-sensitive resin composition, a pattern forming method, and a resin corresponding to a reaction intermediate of the resin.

The instant disclosure relates to saponified pellets of an ethylene-vinyl ester based copolymer as well as a film and a multilayer structure formed therefrom. The saponified pellets of an ethylene-vinyl ester based copolymer has an ethylene content of 24-35 mole %, and the pellets have a turbidity of less than 300 NTU when dissolved in a 60% (w/w) methanol aqueous solution; or the pellet has an ethylene content of 36-48 mole %, and the pellets have a turbidity of less than 200 NTU when dissolved in a 80% (w/w) methanol aqueous solution. The present invention controls the amount of aggregates by controlling the turbidity of the saponified pellets of an ethylene-vinyl ester based copolymer dissolved in methanol aqueous to reduce the amount of gel produced after film formation.

The instant disclosure relates to saponified pellets of an ethylene-vinyl ester based copolymer as well as a film and a multilayer structure formed therefrom. The saponified pellets of an ethylene-vinyl ester based copolymer has an ethylene content of 24-35 mole %, and the pellets have a turbidity of less than 300 NTU when dissolved in a 60% (w/w) methanol aqueous solution; or the pellet has an ethylene content of 36-48 mole %, and the pellets have a turbidity of less than 200 NTU when dissolved in a 80% (w/w) methanol aqueous solution. The present invention controls the amount of aggregates by controlling the turbidity of the saponified pellets of an ethylene-vinyl ester based copolymer dissolved in methanol aqueous to reduce the amount of gel produced after film formation.

The copolymer includes divalent units represented by formula —[CF.sub.2—CF.sub.2]—, at least one divalent unit represented by formula (I): and at least one divalent unit independently represented by formula (II): A is —N(RF.sup.a).sub.2 or a is non-aromatic, 5- to 8-membered, perfluorinated ring comprising one or two nitrogen atoms in the ring and optionally comprising at least one oxygen atom in the ring, each RFa is independently linear or branched perfluoroalkyl having 1 to 8 carbon atoms and optionally interrupted by at least one catenated O or N atom, each Y is independently —H or —F, with the proviso that one Y may be —CF.sub.3, h is 0, 1, or 2, each i is independently 2 to 8, and j is 0, 1, or 2. A catalyst ink and polymer electrolyte membrane including the copolymer are also provided.

##STR00001##

The copolymer includes divalent units represented by formula —[CF.sub.2—CF.sub.2]—, at least one divalent unit represented by formula (I): and at least one divalent unit independently represented by formula (II): A is —N(RF.sup.a).sub.2 or a is non-aromatic, 5- to 8-membered, perfluorinated ring comprising one or two nitrogen atoms in the ring and optionally comprising at least one oxygen atom in the ring, each RFa is independently linear or branched perfluoroalkyl having 1 to 8 carbon atoms and optionally interrupted by at least one catenated O or N atom, each Y is independently —H or —F, with the proviso that one Y may be —CF.sub.3, h is 0, 1, or 2, each i is independently 2 to 8, and j is 0, 1, or 2. A catalyst ink and polymer electrolyte membrane including the copolymer are also provided.

##STR00001##

Provided is a novel polishing composition. The polishing composition comprises a water-soluble polymer at least comprising a vinyl alcohol-based resin having a side-chain group of 3 carbon atoms or more.