Lubricant composition for initial break-in, sliding member, and sliding member manufacturing method

Patent metadata

Field	Value
Publication number	US-11739279-B2
Application number	US-201917275080-A
Country	US
Kind code	B2
Filing date	Aug 28, 2019
Priority date	Sep 11, 2018
Publication date	Aug 29, 2023
Grant date	Aug 29, 2023

Abstract

Provided is an initial break-in lubricant composition capable of easily and economically reducing the coefficient of friction of a sliding portion. The initial break-in lubricant composition includes an organic dispersion medium and nanocarbon particles in a quantity from 0.1 to 2000 ppm by mass. The nanocarbon particles are preferably particles of one or more nanocarbon material(s) selected from the group consisting of: nanodiamonds, fullerenes, graphene oxide, nanographite, carbon nanotubes, carbon nanofilaments, onion-like carbon, diamond-like carbon, amorphous carbon, carbon black, carbon nanohorns, and carbon nanocoils.

First claim

The invention claimed is:

1. An initial break-in lubricant composition comprising an organic dispersion medium, and a nanocarbon particle in a quantity from 0.1 to 500 ppm by mass, wherein the nanocarbon particle is a surface-modified nanodiamond particle, the surface of which is modified by at least one selected from a group consisting of silane compounds, a phosphonate ion, phosphonic acid residue, a surface-modifying group having a vinyl group at a terminal, a cation of a cationic surfactant, a group containing a polyglycerin chain, and a group containing a polyethylene glycol chain.

2. The initial break-in lubricant composition according to claim 1 , wherein the organic dispersion medium is one or more selected from the group consisting of: a polyol ester, a poly-α-olefin, a mineral oil, an alkylbenzene, and a polyalkylene glycol.

3. The initial break-in lubricant composition according to claim 1 , wherein an average dispersed particle size D50 of the nanocarbon particle is from 4 to 80 nm.

4. The initial break-in lubricant composition according to claim 1 , having a coefficient of friction of 0.14 or less after 200 m sliding when used as an initial break-in lubricant on an SUJ2 sliding surface, the friction coefficient as measured by Friction Test 1 as follows:
Friction Test 1: Using a ball-on-disk sliding friction testing apparatus including a disk having an SUJ2 sliding surface on its surface and a ball having an SUJ2 sliding surface on its surface, a coefficient of friction between the disk and the ball is measured when the ball is sliding 200 m under a load of 10 N at a speed of 50 mm/s with 1 mL of the initial break-in lubricant composition being applied dropwise.

5. The initial break-in lubricant composition according to claim 1 , having 0.90 to 1.10 as a ratio between a coefficient of friction after 400 m sliding when the initial break-in lubricant composition is used as an initial break-in lubricant on an SUJ2 sliding surface and a coefficient of friction after 750 m sliding when another lubricant is used, the ratio being [the former coefficient of friction]/[the latter coefficient of friction] as measured by Friction Test 2 as follows:
Friction Test 2: Using a ball-on-disk sliding friction testing apparatus including a disk having an SUJ2 sliding surface on its surface and a ball having an SUJ2 sliding surface on its surface, a coefficient of friction between the disk and the ball is measured when the ball is sliding 400 m under a load of 10 N at a speed of 50 mm/s with 1 mL of the initial break-in lubricant composition being applied dropwise, and after the initial break-in lubricant composition is removed, a coefficient of friction between the disk and the ball is measured when the ball is further sliding 750 m, a total of 1150 m, under a load of 10 N at a speed of 50 mm/s with 1 mL of a polyol ester being applied dropwise.

6. The initial break-in lubricant composition according to claim 1 , which has a haze value of 5 or less.

7. The initial break-in lubricant composition according to claim 1 , wherein an average dispersed particle size D50 of the nanocarbon particle is from 10 to 100 nm.

Assignees

• Daicel Corp

Inventors

• Kimoto Norihiro
• Goto Tomohiro
• Kageyama Hiroki

Classifications

• C10M125/02 Primary

  Carbon; Graphite · CPC title

• C10M169/04

  Mixtures of base-materials and additives · CPC title

• F16C33/043

  Sliding surface consisting mainly of ceramics, cermets or hard carbon, e.g. diamond like carbon [DLC] · CPC title

• C10M2201/041

  Carbon; Graphite; Carbon black · CPC title

• C10N2020/06

  Particles of special shape or size · CPC title