The present invention provides an epoxy resin composition that is provided with flexibility to combine impact resistance and mechanical strength, while maintaining epoxy resin-specific high elastic modulus, that reduces an increase in viscosity due to mixing, and that is excellent in heat resistance, storage stability, and solvent resistance. Provided is an epoxy resin composition containing: a modified polyvinyl acetal resin having a constitutional unit with an acid-modified group; a reactive diluent; and an epoxy resin, the epoxy resin composition having a sea-island phase separated structure after being cured.

An object of the present disclosure is to provide an encapsulation resin in which the occurrence of cracks is suppressed when the resin is used for encapsulation of ultraviolet light-emitting elements. Another object of the present disclosure is to provide an encapsulation resin composition for supplying the encapsulation resin. The present disclosure relates to an encapsulation resin for light-emitting elements, comprising a fluoropolymer, wherein the fluoropolymer comprises, as a main component, a monomer unit represented by formula (1):

##STR00001##

wherein R.sup.1 to R.sup.4 are each independently a fluorine atom, a fluoroalkyl group, or a fluoroalkoxy group.

An object of the present disclosure is to provide an encapsulation resin in which the occurrence of cracks is suppressed when the resin is used for encapsulation of ultraviolet light-emitting elements. Another object of the present disclosure is to provide an encapsulation resin composition for supplying the encapsulation resin. The present disclosure relates to an encapsulation resin for light-emitting elements, comprising a fluoropolymer, wherein the fluoropolymer comprises, as a main component, a monomer unit represented by formula (1):

##STR00001##

wherein R.sup.1 to R.sup.4 are each independently a fluorine atom, a fluoroalkyl group, or a fluoroalkoxy group.

An object of the present disclosure is to provide a protective display film famed from a fluoropolymer with hardness. The present disclosure relates to a protective display film comprising a fluoropolymer, wherein the fluoropolymer comprises, as a main component, a monomer unit represented by formula (1):

##STR00001##

wherein R.sup.1 to R.sup.4 are each independently a fluorine atom, a fluoroalkyl group, or a fluoroalkoxy group.

An object of the present disclosure is to provide a protective display film famed from a fluoropolymer with hardness. The present disclosure relates to a protective display film comprising a fluoropolymer, wherein the fluoropolymer comprises, as a main component, a monomer unit represented by formula (1):

##STR00001##

wherein R.sup.1 to R.sup.4 are each independently a fluorine atom, a fluoroalkyl group, or a fluoroalkoxy group.

An interlayer film for laminated glass, comprising a first layer containing a polyvinyl acetal-based resin, wherein the first layer contains no plasticizer or contains a plasticizer in an amount of 15 parts by mass or less based on 100 parts by mass of the resin contained in the first layer, and the first layer has a glass transition temperature (Tg) of 50° C. or lower.

An interlayer film for laminated glass, comprising a first layer containing a polyvinyl acetal-based resin, wherein the first layer contains no plasticizer or contains a plasticizer in an amount of 15 parts by mass or less based on 100 parts by mass of the resin contained in the first layer, and the first layer has a glass transition temperature (Tg) of 50° C. or lower.

Some embodiments of the present disclosure relate to a method comprising obtaining a mixture comprising at least one vinyl polymer, at least one organic acid, and at least one hydronium ion donor. In some embodiments, the method comprises reacting an —OH group of the B polymer chain segment with the at least one organic acid in the presence of the at least one hydronium ion donor, so as to form at least one polyvinyl ester. Some embodiments of the present disclosure relate to a roofing material comprising at least one reinforcement material and at least one polyvinyl ester.

Some embodiments of the present disclosure relate to a method comprising obtaining a mixture comprising at least one vinyl polymer, at least one organic acid, and at least one hydronium ion donor. In some embodiments, the method comprises reacting an —OH group of the B polymer chain segment with the at least one organic acid in the presence of the at least one hydronium ion donor, so as to form at least one polyvinyl ester. Some embodiments of the present disclosure relate to a roofing material comprising at least one reinforcement material and at least one polyvinyl ester.

Some embodiments of the present disclosure relate to a method comprising obtaining a mixture comprising at least one vinyl polymer, at least one organic acid, and at least one hydronium ion donor. In some embodiments, the method comprises reacting an —OH group of the B polymer chain segment with the at least one organic acid in the presence of the at least one hydronium ion donor, so as to form at least one polyvinyl ester. Some embodiments of the present disclosure relate to a roofing material comprising at least one reinforcement material and at least one polyvinyl ester.