Nanodiamond dispersion composition
Provided is a nanodiamond dispersion composition having excellent dispersibility of nanodiamond particles in an organic dispersion medium. A nanodiamond dispersion composition including an organic dispersion medium, nanodiamond particles dispersed in the organic dispersion medium, and a fatty acid ester dispersing agent, the nanodiamond particles being surface-modified by a surface-modifying group or compound containing an organic group. The fatty acid ester dispersing agent preferably has a mass loss rate of 30% or less when held in an air atmosphere at a temperature of 200° C. for 180 minutes.
1 . A nanodiamond dispersion composition comprising an organic dispersion medium, nanodiamond particles dispersed in the organic dispersion medium, and a fatty acid ester dispersing agent,
the nanodiamond particles being surface-modified by a surface-modifying group or compound containing an organic group,
wherein a content of the fatty acid ester dispersing agent with respect to 100 parts by mass of a total amount of the nanodiamond particles in the nanodiamond dispersion composition is from 10 to 1000 parts by mass.
2 . The nanodiamond dispersion composition according to claim 1 , wherein a content ratio of the nanodiamond particles is greater than 3.0 mass %.
3 . The nanodiamond dispersion composition according to claim 1 , wherein the fatty acid ester dispersing agent has a mass loss rate of 30% or less when the fatty acid ester dispersing agent is held in an air atmosphere at a temperature of 200° C. for 180 minutes.
4 . The nanodiamond dispersion composition according to claim 1 , wherein the fatty acid ester dispersing agent has an acid value of 40 mgKOH/g or less.
5 . The nanodiamond dispersion composition according to claim 1 , wherein the nanodiamond particles has an average dispersed particle size from 2 to 240 nm.
6 . The nanodiamond dispersion composition according to claim 1 , wherein the nanodiamond dispersion composition has a haze value of 5 or less.
7 . The nanodiamond dispersion composition according to claim 1 , wherein the organic dispersion medium has an SP value from 6.0 to 12.0 (cal/cm 3 ) 1/2 .
8 . The nanodiamond dispersion composition according to claim 1 , wherein the nanodiamond dispersion composition has a viscosity from 0.2 to 120 mPa·s at 25° C.
9 . The nanodiamond dispersion composition according to claim 1 , wherein the fatty acid ester dispersing agent has an average molecular weight Mp of 300 or greater.
10 . The nanodiamond dispersion composition according to claim 1 , wherein the nanodiamond particle contains a surface-modified nanodiamond in which a surface of a nanodiamond particle is modified by a group represented by Formula (I):
—X—R (I)
where X represents —Si—, —NH—, —O—, —O—C(═O)—, —C(═O)—O—, —NH—C(═O)—, —C(═O)—NH—, or —S—, and the bond extending to the left from X binds to the nanodiamond particle, and R represents a monovalent organic group, and an atom that binds to X is a carbon atom.
11 . The nanodiamond dispersion composition according to claim 10 , wherein X in Formula (I) represents —Si—, —NH—, —O—, or —O—C(═O)—.
12 . The nanodiamond dispersion composition according to claim 1 , wherein the fatty acid ester dispersing agent has an amine value of 5 mgKOH/g or less.
13 . The nanodiamond dispersion composition according to claim 1 , wherein the content of the fatty acid ester dispersing agent with respect to 100 parts by mass of a total amount of the nanodiamond particles in the nanodiamond dispersion composition is from 10 to 300 parts by mass.
14 . The nanodiamond dispersion composition according to claim 1 , wherein a content ratio of the fatty acid ester dispersing agent with respect to a total amount of a dispersing agent contained in the nanodiamond dispersion composition is 90 mass % or more.
15 . The nanodiamond dispersion composition according to claim 10 , wherein the monovalent organic group is a monovalent substituted or unsubstituted hydrocarbon group, a group in which a monovalent substituted or unsubstituted hydrocarbon group and an alkoxy group are bonded, or a group in which a monovalent substituted or unsubstituted hydrocarbon group and a dialkylamino group are bonded.
16 . The nanodiamond dispersion composition according to claim 10 , wherein a number of carbon atoms in the monovalent organic group is from 4 to 25.
17 . The nanodiamond dispersion composition according to claim 10 , wherein in Formula (I), X is —NH—, and R is a monovalent organic group containing from 8 to 20 carbon atoms.
18 . The nanodiamond dispersion composition according to claim 10 , wherein in Formula (I), R includes a hydrocarbon group having 4 or more carbon atoms in a straight chain.
19 . The nanodiamond dispersion composition according to claim 10 , wherein in Formula (I), a molar ratio of carbon atoms to a total amount of heteroatoms selected from the group consisting of nitrogen atoms, oxygen atoms, sulfur atoms, and silicon atoms is 4.5 or greater.
20 . The nanodiamond dispersion composition according to claim 1 , wherein the organic dispersion medium contains a lubricant base material, and a content of a solvent other than the lubricant base material with respect to 100 parts by mass of the total amount of the nanodiamond particles is less than 1000 parts by mass.