The present invention concerns a coolant, present as an emulsion in the form of a concentrate, for machining fiber-reinforced plastics and material combinations containing fiber-reinforced plastics and metals; furthermore, the present invention also concerns a coolant, present as a solution in the form of concentrate, for machining fiber-reinforced plastics.

The present invention provides a dialkyl polysulfide which can be suitably used as an extreme pressure additive that can be added to a lubricant in a wide range of amounts, that enables effective formation of a film of a metal sulfide on a metal surface, and that is less likely to cause corrosion of the metal surface. In particular, provided is a dialkyl polysulfide containing compounds represented by General Formula (1) (where R.sup.1 and R.sup.2 each represent an alkyl group, and n is an integer from 1 to 6), wherein the total content of a compound in which n in General Formula (1) is 2 and a compound in which n in General Formula (1) is 3 is in the range of 80 to 100 mass % relative to the entire amount of the compounds represented by General Formula (1).

The present invention provides a dialkyl polysulfide which can be suitably used as an extreme pressure additive that can be added to a lubricant in a wide range of amounts, that enables effective formation of a film of a metal sulfide on a metal surface, and that is less likely to cause corrosion of the metal surface. In particular, provided is a dialkyl polysulfide containing compounds represented by General Formula (1) (where R.sup.1 and R.sup.2 each represent an alkyl group, and n is an integer from 1 to 6), wherein the total content of a compound in which n in General Formula (1) is 2 and a compound in which n in General Formula (1) is 3 is in the range of 80 to 100 mass % relative to the entire amount of the compounds represented by General Formula (1).

A random copolymer suitable for reducing friction in lubricant compositions is disclosed. The random copolymer can include a short chain acrylate, a long chain acrylate, and a polar acrylate. The random copolymer can have a ratio of short chain acrylate to long chain acrylate of 0 to 2, and a molecular weight number of 1000 to 10000. The disclosure can include a lubricant containing a base oil and the random copolymer. A process for preparing the random copolymer and polymeric friction modifiers is also disclosed.

A heat treating oil composition containing one or more of a base oil (A) selected from the group consisting of a mineral oil (A1), a synthetic oil (A2) and a vegetable oil (A3), a sulfur compound (B), and a carboxylic acid-based compound (C) being one or more selected from the group consisting of a compound having at least one carboxy group, and an anhydride thereof.

Disclosed is a lubricating oil composition containing a base oil, a viscosity index improver, a molybdenum-based friction modifier, a boron-containing dispersant, and at least two extreme-pressure additives selected from a sulfur-based extreme-pressure additive, a phosphorous-based extreme-pressure additive and a sulfur/phosphorus-based extreme-pressure additive, or a sulfur/phosphorus-based extreme-pressure additive. The base oil is a synthetic oil having a kinematic viscosity at 100 C. of 3 mm.sup.2/s or more and 10 mm.sup.2/s or less, the viscosity index improver is a resin having a number average molecular weight (Mn) of 1,000 or more and 10,000 or less, the mass ratio of boron atoms (B) contained in the boron-containing dispersant to molybdenum atoms (Mo) contained in the molybdenum-based friction modifier, [(B)/(Mo)] is 1 or more and 5 or less, and the mass ratio of sulfur atoms (S) to phosphorus atoms (P) contained in the extreme-pressure additive(s), [(S)/(P)] is 10 or more and 20 or less.

Disclosed is a lubricating oil composition containing a base oil, a viscosity index improver, a molybdenum-based friction modifier, a boron-containing dispersant, and at least two extreme-pressure additives selected from a sulfur-based extreme-pressure additive, a phosphorous-based extreme-pressure additive and a sulfur/phosphorus-based extreme-pressure additive, or a sulfur/phosphorus-based extreme-pressure additive. The base oil is a synthetic oil having a kinematic viscosity at 100 C. of 3 mm.sup.2/s or more and 10 mm.sup.2/s or less, the viscosity index improver is a resin having a number average molecular weight (Mn) of 1,000 or more and 10,000 or less, the mass ratio of boron atoms (B) contained in the boron-containing dispersant to molybdenum atoms (Mo) contained in the molybdenum-based friction modifier, [(B)/(Mo)] is 1 or more and 5 or less, and the mass ratio of sulfur atoms (S) to phosphorus atoms (P) contained in the extreme-pressure additive(s), [(S)/(P)] is 10 or more and 20 or less.

Provided is a non-Newtonian engine oil lubricant composition with improved fuel efficiency and engine wear protection. The lubricant composition includes a major amount of a base oil including a Group II base stock and an optional Group V base stock, from 0.1 to 9.0 wt. % of at least one viscosity modifier and from 0.1 to 1.2 wt. % of at least one friction modifier. The non-Newtonian engine oil lubricant composition has a kinematic viscosity at 100 deg. C. of less than or equal to 10 cSt and an HTHS (ASTM D4683) of less than or equal to 2.2 cP at 150 C. Also provided are methods of using the lubricant composition in internal combustion engines and methods of making the lubricant composition.

Provided is a non-Newtonian engine oil lubricant composition with improved fuel efficiency and engine wear protection. The lubricant composition includes a major amount of a base oil including a Group II base stock and an optional Group V base stock, from 0.1 to 9.0 wt. % of at least one viscosity modifier and from 0.1 to 1.2 wt. % of at least one friction modifier. The non-Newtonian engine oil lubricant composition has a kinematic viscosity at 100 deg. C. of less than or equal to 10 cSt and an HTHS (ASTM D4683) of less than or equal to 2.2 cP at 150 C. Also provided are methods of using the lubricant composition in internal combustion engines and methods of making the lubricant composition.

The refrigerator lubricating oil of the present invention contains: a base oil containing, as a major component, a polyol ester (A) of a fatty acid (a1) that is a fatty acid having a number of carbon atoms of from 3 to 18 and a polyol (a2) that is selected from neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, and dipentaerythritol; and a disulfide and/or trisulfide compound (B), and the disulfide and/or trisulfide compound (B) is blended in an amount of from 30 to 10,000 ppm by mass in terms of sulfur equivalent based on the total amount of the refrigerator lubricating oil.