Lubricated system comprising a DLC surface

Patent metadata

Field	Value
Publication number	US-10800993-B2
Application number	US-201716088938-A
Country	US
Kind code	B2
Filing date	Mar 14, 2017
Priority date	Apr 8, 2016
Publication date	Oct 13, 2020
Grant date	Oct 13, 2020

Abstract

The present invention relates to a lubricated system comprising: a) a component comprising a first surface which is a diamond-like carbon (DLC) surface; b) a component comprising a second surface; and c) a lubricant formulation interposed between the first surface and second surface. The lubricant formulation comprises: i) a base stock; ii) a molybdenum compound; iii) an organic polymer comprising a hydrophobic polymeric sub unit selected from polyesters and functionalised polyolefins and a hydrophilic polymeric sub unit selected from polyethers; and iv) optionally, other additives. The combination of the molybdenum compound and the organic polymer in the lubricant formulation reduces the wear on one or more of the surfaces in the lubricated system when compared with using the molybdenum containing friction modifier alone.

First claim

The invention claimed is:

1. A lubricated system comprising:
a) a component comprising a first surface which is a diamond-like carbon (DLC) surface;
b) a component comprising a second surface; and
c) a lubricant formulation interposed between the first surface and second surface, wherein the lubricant formulation comprises:
i) a base stock;
ii) 0.05 to 5 wt % of the lubricant formulation of a molybdenum compound comprising a molybdenum dithiocarbamate (MoDTC);
iii) 0.05 to 5 wt % of the lubricant formulation of an organic polymer comprising a hydrophobic polymeric sub unit comprising a polyisobutylene functionalized to comprise a diacid and/or anhydride group and a hydrophilic polymeric sub unit comprising a polyethylene glycol having a number average molecular weight of 400 to 1000 daltons; and
iv) optionally, other additives,

wherein the lubricant formulation reduces kinetic coefficient of friction by at least 5% and reduces wear of the first and/or second surface by at least 50% during operation of the lubricated system when compared with an equivalent lubricant formulation which does not comprise the molybdenum compound and the organic polymer.

2. A lubricated system according to claim 1 wherein the second surface is a metal surface.

3. A lubricated system according to claim 1 wherein the lubricated system is an automotive engine.

4. A lubricated system according to claim 1 wherein the hydrophobic polymeric sub unit comprises a polyisobutylene succinic anhydride.

5. A lubricated system according to claim 1 wherein the organic polymer further comprises a polyol.

6. A lubricated system according to claim 5 wherein the polyol is selected from glycerol, polyglycerol, neopentyl glycol, trimethylolethane, trimethylolpropane, trimethylolbutane, pentaerythritol, dipentaerythritol, tripentaerythritol, sucrose, sorbitan, sorbitol and mixtures thereof.

7. A lubricated system according to claim 1 wherein the organic polymer is a friction reducing additive.

8. A method of reducing wear in a lubricated system by at least 50% and kinetic coefficient of friction by at least 5% during operation of the lubricated system, wherein the lubricated system comprises a component with a DLC surface and wherein the method comprises the steps of:
a. providing a lubricant formulation to contact the DLC surface;
b. providing 0.05 to 5 wt % of the lubricant formulation of a molybdenum compound comprising a molybdenum dithiocarbamate (MoDTC) in the lubricant formulation to reduce friction in the lubricated system; and
c. providing 0.05 to 5 wt % of the lubricant formulation of an organic polymer comprising a hydrophobic polymeric sub unit comprising a polyisobutylene functionalized to comprise a diacid and/or anhydride group and a hydrophilic polymeric sub unit comprising a polyethylene glycol having a number average molecular weight of 400 to 1000 daltons in the lubricant formulation to reduce the rate of wear and friction of the DLC surface during operation of the lubricated system.

Assignees

• Croda Int Plc

Inventors

• Moody Gareth
• Eastwood John
• Viadas Cienfuegos Aitziber

Classifications

• C10M161/00 Primary

  Lubricating compositions characterised by the additive being a mixture of a macromolecular compound and a non-macromolecular compound, each of these compounds being essential · CPC title

• C10N2080/00

  Special pretreatment of the material to be lubricated, e.g. phosphatising or chromatising of a metal · CPC title

• C10M2205/026

  Butene · CPC title

• C10M2207/30

  Complex esters, i.e. compounds containing at leasst three esterified carboxyl groups and derived from the combination of at least three different types of the following five types of compounds: monohydroxyl compounds, polyhydroxy xompounds, monocarboxylic acids, polycarboxylic acids or hydroxy carboxylic acids · CPC title

• C10M2209/102

  Polyesters · CPC title