Summary: We consider a model which describes a polymer chain interacting with an infinity of equi-spaced linear interfaces. The distance between two consecutive interfaces is denoted by \(T = T_{N}\) and is allowed to grow with the size \(N\) of the polymer. When the polymer receives a positive reward for touching the interfaces, its asymptotic behavior has been derived by F. Caravenna and N. Pétrélis [Ann. Appl. Probab. 19, No. 5, 1803–1839 (2009; Zbl 1206.60089)], showing that a transition occurs when \(T_{N}\) grows like \(\log N\). In the present paper, we deal with the so-called depinning case, i.e., the polymer is repelled rather than attracted by the interfaces. Using techniques from renewal theory, we determine the scaling behavior of the model for large \(N\) as a function of \({T_{N}}_{N}\), showing that two transitions occur, when \(T_{N}\) grows like \(N^{1/3}\) and when \(T_{N}\) groes like \(N^{1/2}\) respectively.