Grease

Japanese: グリース

It is a viscous substance that is semi-solid or solid at room temperature, and generally refers to a semi-solid or solid lubricant consisting of a liquid lubricant and a thickener, i.e., lubricating grease. Mineral oil is generally used as a liquid lubricant, but synthetic oils are also used. Thickeners are broadly divided into soap-based and non-soap-based. Soaps are metal soaps such as Li soap and Ca soap. Non-soap-based types are often solid particle dispersion types, and are broadly divided into inorganic compound dispersion types such as bentonite and organic compound dispersion types such as urea. Grease is mainly used under the following conditions: high loads, impact loads, low sliding speeds, high temperatures, infrequent inspections, prevention of external contamination, large gaps in bearings, etc., and when it is necessary to avoid contamination from lubricant splashes and drops. Grease exhibits a phenomenon called thixotropy. When a shear force is applied to grease, it does not flow as long as the shear force is small, but as the force increases it begins to flow and acts as a lubricant, and as the force increases even further it assumes a state close to the viscosity of the base oil. However, when the shear force is removed from the grease, it returns to its original solid state. This phenomenon is related to the micellar structure formed by soap, which acts as a thickening agent in the base oil.

Grease Grease
Griess, Johan Peter

A German-born chemist who was active in England. He studied chemistry at the universities of Jena and Marburg. At the age of 29, he began work as an apprentice at a chemical factory. However, after only a few months, he experienced a fire and the factory burned down, so he was fired and returned to study at the University of Marburg. Although it was only for a short time, his experience at the chemical factory transformed him into a completely different person, and he devoted himself to his studies and experiments in the laboratory of AWH Kolbe. In 1858, he was recommended to become an assistant to R. Hoffmann at the Royal College of Chemistry in London. In 1862, he moved to the industrial world, becoming an engineer at Allsop's Brewery in Burton-on-Trent, a position he held for the rest of his life. He produced a highly reactive diazo compound from aniline as a new type of dye, obtaining an azo pigment, and contributing to the development of synthetic dyes.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

Japanese:

常温で半固体または固体状の粘ちゅうな物質で，一般には液体潤滑油と増ちゅう剤からなる半固体または固体状の潤滑剤，すなわち潤滑グリースをいう．液体潤滑油には，一般に鉱油が用いられるが，合成油も用いられる．増ちゅう剤はセッケン系と非セッケン系に大別される．セッケンはLiセッケン，Caセッケンなどの金属セッケンが用いられる．非セッケン系は固体粒子分散型が多く，ベントナイトなどの無機化合物分散型と，ウレアなどの有機化合物分散型とに大別される．グリースは，主として次のような条件のときに用いられる．すなわち，高負荷，衝撃荷重，すべり速度が小さい，高温，点検が頻繁に行えない，外側からの汚染を防止する，ベアリングなどの間げきが大きい，潤滑剤のハネやしずくによる汚れを避ける必要のあるとき，などである．グリースにはチキソトロピーという現象がある．グリースにせん断力を与えるとせん断力の小さい間は流動を示さないが，大きくなると流動を起こして潤滑作用し，さらに大きくなると基油の粘性に近い状態になる．しかし，グリースへのせん断力が除去されるともとの固体状に戻る．この現象は，基油中での増ちゅう剤としてのセッケンがつくるミセル構造と関係している．

グリース
グリース
Griess, Johan Peter

ドイツ出身でイギリスで活躍した化学者．イエナとマールブルク大学で化学を学ぶ．29歳で化学工場に見習い工員として勤める．しかし，わずか数か月で失火事故を経験，工場全焼のため解雇され，マールブルク大学に復学した．短期間ではあったが，化学工場での経験は，かれを別人のようにかえ，A.W.H. Kolbe(コルベ)の実験室で学業と実験にまい進した．1858年ロンドン王立化学カレッジのR. Hoffmann(ホフマン)のもとで助手に推薦されるまでになった．1862年工業界に転じ，バートン・オン・トレントのオールソップ醸造所の技術士となり，終生その職を守った．新しいタイプの染料として，アニリンから反応性に富むジアゾ化合物を生成し，アゾ色素を得て，合成染料の開発に貢献した．

出典　森北出版「化学辞典（第2版）」化学辞典第2版について　情報

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