Cutting oil - Sessakuyu (English spelling) cutting oil

Oils used for lubrication, cooling, and corrosion prevention when cutting, polishing, drilling, etc. metals with lathe tools. They are broadly divided into water-insoluble cutting oils that have enhanced lubricating properties by adding petroleum sulfonates, sulfurized oils, and other oil-soluble compounds containing phosphorus and chlorine to a base of mineral oil or fats, and water-soluble cutting oils that are soluble in water and emphasize cooling properties during high-speed cutting. The latter are further classified into emulsion, soluble and solution types, but generally, when 5 to 10% oil-in-water (o/w) emulsifier (sulfonate, rosin acid, naphthenic acid, alkylolamine soap of fatty acids, polyoxyethylene-based nonionic surfactants, Emulphor STH type RSO ₂ NHCH ₂ COONa surfactants, etc.) is added to light mineral oil, and then alcohols, glycol ethers, terpene solvents, defoamers, bactericides, hard water softeners, etc. are blended, and then water is added, a stable emulsion or transparent solution with excellent load-bearing and rust-preventing properties is obtained.

[Mitsuo Okahara]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

旋盤工具類による金属の切断、研摩、穿孔(さくこう)などの際に、潤滑、冷却、防食などの目的で用いられる油。鉱油、油脂をベースとして石油スルホン酸塩、硫化油脂その他リン、塩素などを含む油溶性化合物を添加して、潤滑性能を高めた水不溶性の不水溶性切削油と、高速切削の際の冷却性を重視した水に可溶性の水溶性切削油に大別される。後者はさらに乳化型、可溶型および溶液型に分類されるが、一般に軽質鉱油に5～10％の水中油滴型（o／w型）乳化剤（スルホン酸塩、ロジン酸、ナフテン酸、脂肪酸のアルキロールアミンせっけん、ポリオキシエチレン系非イオン活性剤、エマルホアSTH型RSO₂NHCH₂COONa界面活性剤など）を添加し、さらにアルコール類、グリコールエーテル類、テルペン系溶剤、消泡剤、殺菌剤、硬水軟化剤などを配合したもので水を加えた場合、耐荷重性、防錆(ぼうせい)効果の優れた安定な乳液もしくは透明溶液が得られる。

［岡原光男］

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