PROBLEM TO BE SOLVED: To provide a surface modification method of a vulcanizate or a thermoplastic elastomer having a lubrication surface, which is not a resin coating having problems such as reduction of lubricity due to peel or separation during transportation in a pipe, but is chemically immobilized.SOLUTION: There is provided a surface modification method for a vulcanizate or a thermoplastic elastomer as a modification target and including a process 1 for forming a polymer initiation point on a surface of the modification target and a process 2 for radical polymerizing a monomer by irradiating a UV light with 300 to 400 nm in the presence of an alkali metal salt with the polymerization initiation point as a starting point and growing a polymer chain on a surface of the modification target.SELECTED DRAWING: None【課題】管内の移動時に剥がれやめくれ等により潤滑性が低下する等の問題点がある樹脂コーティングではなく、化学的に固定化された潤滑表面を有する加硫ゴム又は熱可塑性エラストマーの表面改質方法を提供する。【解決手段】加硫ゴム又は熱可塑性エラストマーを改質対象物とする表面改質方法であって、前記改質対象物の表面に重合開始点を形成する工程１と、前記重合開始点を起点にして、アルカリ金属塩の存在下で、３００～４００ｎｍのＵＶ光を照射してモノマーをラジカル重合させ、前記改質対象物の表面にポリマー鎖を成長させる工程２とを含む表面改質方法。【選択図】なし
