US 10,175,578 B2  58  57  In a case where the compound (A3) having a radical  trapping group is a low molecular compound, the molecular  weight is not particularly limited, and the molecular weight  is preferably 100 to 5,000, more preferably 100 to 2,000, and  still more preferably 100 to 1,000.  Furthermore, in a case where the compound (A3) having  a radical trapping group is a polymer compound having a  repeating unit, the weight-average molecular weight is pref› erably 5,000 to 20,000, and more preferably 5,000 to 10,000.  As the compound (A3) having a radical trapping group, a  compound that is a commercially available product may be  used, and a compound synthesized by a known method may  be used. Further, the compound (A3) may be synthesized by  the reaction of a commercially available low molecular  compound having a radical trapping group with a polymer  compound having a reactive group such as an epoxy group,  a halogenated alkyl group, an acid halide group, a carboxyl  group, and an isocyanate group.  The content of the compound (A3) having a radical  trapping group is usually 0.001% to 10% by mass, and  preferably 0.01 % to 5% by mass, with respect to the total  solid content of the topcoat composition.  The topcoat composition may include a plurality of one  kind of compound selected from the group consisting of  (Al) to (A3). For example, the topcoat composition may  also include two or more kinds of the distinctive compounds  (Al).  In addition, the topcoat composition may contain two or  more kinds of compounds selected from the group consist› ing of (Al) to (A3). For example, the topcoat composition  may also contain both of the compound (Al) and the  compound (A2).  In a case where the topcoat composition includes a  plurality of compounds selected from the group consisting  of (Al) to (A3), the total content of the compounds is usually  Furthermore, as described above, the compound (A3) may  be a polymer compound having a repeating unit. Specific  examples of the repeating unit contained in the compound  (A3) which is a polymer compound are shown below, but the  present invention is not limited thereto.  0  0  HN~I  HN~Cl  :D<:D<  I  I  o.  o.  -0<-0<~  I  I  I  o.  o.  o.  0  +I S02Na  0  ~+  0-N  ~  0  + ’=---C~fi  0  N- ’I  N-0  '  0~+  0-N  ~  -continued 