The ornamental design for a binderclip, as shown and described.
FIG. 1 is a front isometric view of a binder clip, according to the present design;
FIG. 2 is a back isometric view thereof;
FIG. 3 is a top isometric view thereof;
FIG. 4 is a bottom isometric view thereof;
FIG. 5 is a right isometric view thereof;
FIG. 6 is a left isometric view thereof; and,
FIG. 7 is a front and side perspective view of the binder clip.
The broken lines showing the binding sheet and portions of the binder clip in FIGS. 4, 5, 6, and 7 are included to show features that form no part of the claimed design.