PROBLEM TO BE SOLVED: To provide a first agent for oxidation hair dyeing that can dye hair more evenly and has a pH of 9.0 or less, an oxidation hair dye that includes the first agent mixed therein, and a hair dyeing treatment method.SOLUTION: A first agent for oxidation hair dyeing contains the following (A), (B) and (C) and has a pH of 9.0 or less: (A) an oxidation dye, (B) a protein hydrolysate and/or a derivative thereof, and (C) a polyphenol having the property of binding to the (B) to form a complex. There are also provided an oxidation hair dye that includes the first agent mixed therein, and a hair dyeing treatment method using the oxidation hair dye.SELECTED DRAWING: NoneCOPYRIGHT: (C)2018,JPO&INPIT【課題】毛髪の均染性を良好にするための、pH9.0以下の酸化染毛用第1剤、当該第1剤が混合された酸化染毛剤、及び染毛処理方法の提供。【解決手段】下記(A)、(B)及び(C)が配合され、pHが9.0以下である酸化染毛用第1剤、当該第1剤が混合された酸化染毛剤、及びこの酸化染毛剤を使用する酸化染毛処理方法。(A)酸化染料(B)タンパク質加水分解物及び/又はその誘導体(C)前記(B)と結合して複合体となる性質を有するポリフェノール【選択図】なし
