Abstract: An epoxy resin represented by the following formula (1), in which in a total amount of an epoxy compound represented by n=1 in the epoxy resin of the above formula, a total content of an epoxy compound represented by the following formula (2) and an epoxy compound represented by the following formula (3) is 1 area % or more and less than 70 area % in HPLC area percentage.

Abstract: A compound of formula 1: where X and Y are each a different optional organic group. When there is a plurality of X, each X in the plurality of X may be the same as or different from each other. When there is a plurality of Y, each Y in the plurality of Y may be the same as or different from each other. R represents a hydrocarbon group having 1 to 10 carbon atoms or a halogenated alkyl group. When there is a plurality of R, each R in the plurality of R may be the same as or different from each other. Variable m is an integer of 0 to 3, n is a repeating unit and satisfies 1?n?20, and p is a repeating unit and satisfies 0?p?20.

Abstract: The present invention relates to a silver anti-tarnish agent having, as an effective component, a zinc salt and/or a zinc complex, preferably at least one kind selected from the group consisting of a carboxylic acid zinc salt having a carbon atom number of 3 to 20, a phosphoric acid zinc salt, a phosphate ester zinc salt and a carbonyl compound zinc complex; a silver anti-tarnish method for preventing tarnish of a silver part by applying said silver anti-tarnish agent to the silver part. According to the present invention, tarnish of a silver part such as a silver-plated part due to a sulfur-based gas can be prevented. The present invention is useful particularly as a silver anti-tarnish agent for a light-emitting diode and allows preventing tarnish of a silver part of a light-emitting diode and reduction in illuminance by applying the silver anti-tarnish agent of the present invention to a silver part such as a silver-plated part of a light-emitting diode for covering the silver part.