PROBLEM TO BE SOLVED: To provide a deterioration inhibitor having high safety, capable of suppressing oxidation of oil and a manufacturing method thereof.SOLUTION: Shirasu mainly composed of SiO2 and Al2O3 is heated, agitated, and screened to produce fine grained Shirasu. Clay with an iron content in the range from 0.01 to 0.1% and water are added to the fine grained Shirasu. The mixture is kneaded, dried, and fired to produce an oil deterioration inhibitor. The manufacturing method thereof includes: a primary processing step for heating and agitating Shirasu in the range of 350°C to 450°C a selecting step for separating the Shirasu into fine grained Shirasu with a grain size of 0.05 mm mesh and fine grained Shirasu with a grain size of 0.03 mm mesh a forming step for mixing the fine grained Shirasu with a grain size of 0.05 mm mesh and the fine grained Shirasu with a grain size of 0.03 mm mesh at a ratio of 1:4, and adding 10 to 20% aqueous clay composed of clay with an iron content in the range from 0.01 to 0.1% and water to the fine grained Shirasu, and kneading and drying the mixture and a secondary processing step for firing the formed product in a furnace atmosphere at a high temperature of 1300°C or higher.COPYRIGHT: (C)2014,JPO&INPIT【課題】安全性が高く、油の酸化を抑制することができる劣化防止剤、及びその製造方法を提供する。【解決手段】SiO2、Al2O3を主成分とするシラスを加熱撹拌し、該シラスをフルイにかけて細粒シラスを得、該細粒シラスに鉄分含有率0.01~0.1%以下の粘土と水とを加えて混練、乾燥した後、焼成して油劣化防止剤を得る。またその製造方法は、シラスを350℃~450℃の範囲内で加熱撹拌する1次処理工程と、粒度が0.05mmメッシュと0.03mmメッシュの細粒シラスに分ける選別工程と、0.05mmメッシュの細粒シラスと0.03mmメッシュの細粒シラスを1:4の比率で混合し、さらに、鉄分含有率0.01~0.1%以下の粘土に水を加えて濃度10~20%の粘土水とし、該粘土水を前記細粒シラスに加えて混練、乾燥する成形工程と、成形された後に1300℃以上の高温の窯炉雰囲気で焼成する2次処理工程を経る。【選択図】なし
