BOTTLE CAN AND MANUFACTURING METHOD OF THE SAME

To provide a bottle can that can improve corrosion resistance and a manufacturing method of the same.SOLUTION: The manufacturing method of a bottle can includes a coating step in which paint is applied to an inner surface of a cylindrical body having a bottom, a necking step in which the cylindrical body after the coating step is processed to form a tapered part and a small diameter part, and a mouth forming step in which the small diameter part is processed to form a mouth part having a male thread located on an upper side of the tapered part in a can axial direction. The inner surface of the bottom has a can bottom convex part protruding toward an opening end of the cylindrical body, an annular concave part connected to the periphery of the can bottom convex part, and an expanding part connected to the outer edge of the concave part and gradually expanding in diameter toward the upper side of the can axial direction. The coating step includes a first step of applying a first paint to the concave part and the expanding part, a second step of applying a second paint to the inner surface of the bottom and the inner surface of the area other than the area that is the male thread part and the curl part in the cylindrical body after the first step, and a third step of applying a third paint to the inner surface of the area that is the male thread part and the curl part in the cylindrical body.SELECTED DRAWING: Figure 1 【課題】耐食性を向上できるボトル缶及びその製造方法を提供すること。【解決手段】底部を有する円筒状の筒体の内面に塗料を塗布する塗布工程と、塗布工程後の筒体を加工して、テーパ部及び小径部を形成するネッキング工程と、小径部を加工して、テーパ部の缶軸方向上側に位置する雄ねじ部を有する口部を形成する口部成形工程と、を備え、底部の内面は、筒体の開口端に向けて突出する缶底凸部と、缶底凸部の周縁部に接続される環状の凹部と、凹部の外周端に接続され、缶軸方向上側に向かうに従って漸次拡径する拡径部と、を有し、塗布工程は、凹部及び拡径部に第１塗料を塗布する第１工程と、第１工程後に底部の内面及び筒体における雄ねじ部及びカール部となる領域以外の領域の内面に第２塗料を塗布する第２工程と、筒体における雄ねじ部及びカール部となる領域の内面に第３塗料を塗布する第３工程と、を有する。【選択図】図１