AU2019250113B2 - Method of manufacturing nanodiamonds and nanodiamonds - Google Patents

Abstract

#$%^&*AU2019250113B220250814.pdf##### Abstract Object Provided is a method capable of producing nanodiamonds having a large specific surface area. Solution to Problem The method of manufacturing nanodiamonds according to the present invention includes producing nanodiamonds by detonating an explosive in a container under a condition where a ratio of volume of the container to mass of the explosive [the volume of the container (m3)/the mass of the explosive (kg)] is 10 or less. The volume of the container is preferably from 0.05 to 10 M3. The mass of the explosive is preferably from 0.07 to 1 kg. A nanodiamond content in a nanodiamond crude product obtained in the producing nanodiamonds is preferably from 5 to 55 mass%. Selected Drawing: FIG. 1 11786948_1 (GHMatters) P112226.AU Abstract Object Provided is a method capable of producing nanodiamonds having a large 2019250113 15 Oct 2019 specific surface area. Solution to Problem The method of manufacturing nanodiamonds according to the present invention includes producing nanodiamonds by detonating an explosive in a container under a condition where a ratio of volume of the container to mass of the explosive [the volume of the container (m³)/the mass of the explosive (kg)] is 10 or less. The volume of the container is preferably from 0.05 to 10 m³. The mass of the explosive is preferably from 0.07 to 1 kg. A nanodiamond content in a nanodiamond crude product obtained in the producing nanodiamonds is preferably from 5 to 55 mass%. Selected Drawing: FIG. 1 11786948_1 (GHMatters) P112226.AU 1/1 20 19 25 01 13 1 5 O ct 2 01 9 1/1Oct 2019 2019250113 15 S1 PRODUCING NANODIAMONDS S2 ACID-TREATING S3 OXIDIZING S4 ALKALI AND HYDROGEN PEROXIDE-TREATING S5 DRYING FIG. 1

Description

1/1 1/1 15 Oct 2019 Oct 2019

2019250113 15 2019250113

S1

PRODUCING NANODIAMONDS

S2 ACID-TREATING

S3 OXIDIZING

S4

ALKALI AND HYDROGEN PEROXIDE-TREATING

S5

DRYING

FIG. 1

METHOD OF METHOD OF MANUFACTURING MANUFACTURING NANODIAMONDS NANODIAMONDSAND AND NANODIAMONDS NANODIAMONDS

Technical Field Technical Field 55 [0001]

[0001] The present invention The present invention relates relates to to aa method ofmanufacturing method of manufacturing nanodiamonds nanodiamonds andand nanodiamonds. nanodiamonds. More More specifically, specifically, the present the present invention invention

relates to relates to aamethod of manufacturing method of nanodiamonds manufacturing nanodiamonds and and nanodiamonds nanodiamonds

obtained by obtained by the the method methodofofmanufacturing manufacturingthethe same. same.

10 10

Background Art Background Art

[0002]

[0002]

Nanodiamonds Nanodiamonds are are ultrafine ultrafine diamond diamond particles particles having having an extremely an extremely largelarge

specific surface specific surface area, area, and and have have high mechanicalstrength, high mechanical strength, and andexcellent excellent 15 electrical 15 electricalinsulating insulatingproperties propertiesand andheat heatconductive conductive properties.InInaddition, properties. addition, nanodiamonds nanodiamonds exhibit exhibit a deodorizing a deodorizing effect,antimicrobial effect, antimicrobialeffect, effect,and andchemical chemical resistance. Therefore, resistance. Therefore, nanodiamonds areused nanodiamonds are used as as abrasivematerials, abrasive materials, conductivity imparting conductivity imparting materials, materials, insulating insulating materials, materials, deodorizing agents, and deodorizing agents, and antimicrobial agents, antimicrobial agents, for for example. example.

20 [0003] 20 [0003] Typically, Typically, nanodiamonds nanodiamonds areare synthesized synthesized by by a detonation a detonation method. method. The The

nanodiamonds nanodiamonds obtained obtained by by thethe detonation detonation method method oftenoften form form aggregates. aggregates. By By crushingthetheaggregates crushing aggregates usingusing a milla such mill as such as mill, a bead a beadso-called mill, so-called single-digit single-digit

nanodiamonds nanodiamonds having having a median a median diameter diameter (D50)(D50) of less of less than than 10 nm10are nmobtained are obtained 25 (see 25 (seePatent Patent Documents Documents1 1and and2). 2).

CitationList Citation List Patent Patent Document Document

[0004]

[0004]

30 30 Patent Document Document 1: 1: JPJP 2005-001983 2005-001983 A A Patent Document Patent Document 2: 2:JPJP 2010-126669 2010-126669 A A

SummaryofofInvention Summary Invention

[0005]

[0005]

35 35 With the detonation With the detonation method, method,ititis is relatively relatively easy easy to to manufacture manufacture

nanodiamonds nanodiamonds with with a specificsurface a specific surfacearea areaofofapproximately approximately 300300 m2but m²/g, /g, but it is it is

difficult totomanufacture difficult manufacture nanodiamond having nanodiamond having an an even even larger larger specific specific surface surface

area, for area, for example, example, a specific specific surface surface area area of of approximately m 2/gororgreater. 320m²/g approximately 320 greater.

1 11786948_1 (GHMatters) 11786948_1 (GHMatters) P112226.AU P112226.AU

[0006] 17 Jul 2025

An embodiment of the present invention provides a method of manufacturing nanodiamonds that may be capable of producing nanodiamonds 21921716_1 (GHMatters) P112226.AU

having a large specific surface area. 5 [0007] The present inventors discovered that nanodiamonds having a large specific surface area can be obtained by a method of manufacturing 2019250113

nanodiamonds. Embodiments provide a method of manufacturing nanodiamonds, comprising producing nanodiamonds by detonating an explosive 10 in a container under a condition where a ratio of volume of the container to mass of the explosive [the volume of the container (m 3 )/the mass of the explosive (kg)] is in a specific range. Embodiments of the present invention have been completed based on these findings.

[0008] 15 An aspect of the present invention provides a method of manufacturing nanodiamonds that includes producing nanodiamonds by detonating an explosive in a container under a condition where a ratio of volume of the container to mass of the explosive [the volume of the container (m 3 )/the mass of the explosive (kg)] is 10 or less. 20 [0009] The volume of the container may preferably be from 0.05 to 10 m 3 .

[0009a] In which case, another aspect of the present invention provides a method of manufacturing nanodiamonds, comprising producing nanodiamonds by 25 detonating an explosive in a container under a condition where a ratio of volume of the container to mass of the explosive [the volume of the container (m 3 )/the mass of the explosive (kg)] is 1 to 10 and the volume of the container is from 0.05 to 0.2 m3

[0010] 30 The mass of the explosive may preferably be from 0.07 to 1 kg.

[0011] A nanodiamond content in a nanodiamond crude product obtained in the producing nanodiamonds may preferably be from 5 to 55 mass%.

[0012] 35 A particle diameter of the explosive may preferably be from 45 to 2360 µm.

[0013]

2 21921716_1 (GHMatters) P112226.AU 17/07/2025

The explosive may preferably be a mixture of trinitrotoluene and 17 Jul 2025

cyclotrimethylenetrinitramine.

[0014] 21921716_1 (GHMatters) P112226.AU

Another aspect of the present invention further provides nanodiamonds 5 having a median diameter from 4.0 to 5.5 nm and a specific surface area from 320 to 500 m 2 /g, including as obtained or obtainable by a method of manufacturing nanodiamonds herein described. 2019250113

[0015] The nanodiamonds may preferably be detonation nanodiamonds. 10 [0016] With the method of manufacturing nanodiamonds according to an embodiment of the present invention, it may be possible to produce nanodiamonds having a large specific surface area.

15 Brief Description of Drawing

[0017] Embodiments of the disclosure will now be described by way of example only with reference to the accompanying non-limiting Figure: FIG. 1 is a flow chart of an embodiment of a method of manufacturing 20 nanodiamonds according to the present invention.

Description of Embodiments

[0018] The method of manufacturing nanodiamonds according to embodiments 25 of the present invention includes producing nanodiamonds by a detonation method (producing nanodiamonds). Note that the method of manufacturing nanodiamonds according to embodiments of the present invention may be referred to herein simply as “the manufacturing method according to the present invention”. The manufacturing method according to the present invention may 30 include another process, such as purifying, oxygen-oxidizing, or hydrogenating, in addition to the producing nanodiamonds. Examples of the purifying include acid-treating, oxidizing, alkali and hydrogen peroxide-treating, and drying.

[0019] FIG. 1 is a flow chart of an embodiment of the manufacturing method 35 according to the present invention. The embodiment of the manufacturing method according to the present invention illustrated in FIG. 1 includes at least producing nanodiamonds S1,

3 21921716_1 (GHMatters) P112226.AU 17/07/2025 acid-treating S2, oxidizing S3, alkali and hydrogen peroxide-treating S4, 17 Jul 2025 and drying S5.

[0020] 21921716_1 (GHMatters) P112226.AU

Producing Nanodiamonds 5 In producing nanodiamonds, nanodiamonds are produced by a detonation method. More specifically, first, an electric detonator is attached to a molded explosive, and then placed inside a pressure-resistant container for detonation, 2019250113

and the container is sealed in a state in which a gas having a specific composition and the explosive to be used coexist inside the container. In the 10 producing nanodiamonds, then, the electric detonator is ignited, whereby the

3a 21921716_1 (GHMatters) P112226.AU 17/07/2025

explosive is explosive is detonated in the detonated in the container. container. "Detonation" refers to, "Detonation" refers to, among explosive among explosive

reactions associated reactions with chemical associated with chemicalreactions, reactions, one onethat that includes includes aa flame flame surface, surface, where the reaction where the reaction occurs, occurs, traveling traveling at at aa high high speed exceedingthe speed exceeding the speed speedofof sound. During sound. Duringthe thedetonation, detonation, the the explosive explosivethat that is is used used undergoes undergoespartially partially 55 incomplete incomplete combustion combustion and releases and releases carbon, carbon, and the and with withcarbon being being the carbon used used as a as a raw material, raw material, nanodiamonds nanodiamonds areare produced produced by the by the action action of the of the pressure pressure andand

energy of energy of shock shock waves wavesthat thatare areproduced producedin inthe theexplosion. explosion.InInthe theproduction productionofof the nanodiamonds, the first aa product nanodiamonds, first product obtained obtainedthrough throughthethedetonation detonationmethod method is is subjected to subjected to Coulomb Coulombinteraction interactionbetween between crystalplanes, crystal planes,ininaddition additiontotoVan Vander der 10 Walls 10 Walls forces forces between between adjacent adjacent primary primary particles particles or crystallites,to tobe,be,asasa or crystallites, a result, very result, very strongly strongly assembled, thereby forming assembled, thereby formingananaggregate. aggregate.

[0021]

[0021]

In In the the producing nanodiamonds, producing nanodiamonds, thethe explosive explosive is is detonated detonated in in thethe

container under container under aa condition condition where wherea aratio ratio of of the the volume volumeofofthe thecontainer container toto the the 15 mass 15 mass of the of the explosive explosive [the[the volume volume of the of the container container (m3 )/the (m³)/the massmass of of the the explosive(kg)] explosive (kg)] is is 10 10 or or less. less. When When the ratio the ratio is 10 is 10 or or heat less, less,dissipation heat dissipation after after the detonation the becomesslower, detonation becomes slower,and andthus thusgraphitization graphitizationononthethesurface surfaceofofthe the resulting nanodiamond resulting crude nanodiamond crude product product is is promoted. promoted. As As a result, a result, it itisis possible possible to to produce nanodiamonds produce nanodiamonds having having a small a small median median diameter diameter and a and a large large specific specific

20 surface 20 surface area. area. TheThe above-described above-described ratioratio is preferably is preferably from from 0.5 0.5 to 10, to 10, more more

preferably from preferably from 1 1to 7, and to 7, still more and still more preferably preferably from 3.5 to from 3.5 to 5.5. 5.5. When the ratio When the ratio is greater is thanororequal greater than equal to to 0.5, 0.5, thethe primary primary particles particles of theof the resulting resulting

nanodiamonds nanodiamonds exhibit exhibit narrow narrow particle particle diameter diameter distribution,andand distribution, enhanced enhanced

uniformity in particle uniformity in particle diameter can be diameter can be achieved. achieved. Furthermore, Furthermore,the thenanodiamond nanodiamond 25 content 25 content in the in the produced produced nanodiamond nanodiamond crude crude productproduct increases. increases.

[0022]

[0022]

The volume(capacity) The volume (capacity)ofofthe thecontainer containerisis preferably preferably from from0.05 m3 0.05toto1010m³, ,

and more and morepreferably preferablyfrom from0.07 0.07toto0.2 m3 When 0.2m³. . When the the volume volume of the of the container container is is 0.05 m 3 or 0.05 m³ or greater, greater, nanodiamond productivityincreases. nanodiamond productivity increases.When When the the volume volume of of 30 thethe 30 container container is is lessthan less thanororequal m3 heat equaltoto1010m³, , heatdissipation dissipationafter after the the detonation detonation becomes slower,whereby becomes slower, whereby graphitization graphitization on on thethe surface surface of of thethe produced produced

nanodiamond nanodiamond crude crude product product is promoted. is promoted. As aAsresult, a result, thethe particlediameter particle diameter of of

the produced the nanodiamonds produced nanodiamonds can can be reduced. be reduced. Furthermore, Furthermore, the container the container is, is, for for example, made example, madefrom from iron. iron.

35 [0023] 35 [0023] The massofofthe The mass the above-described above-describedexplosive explosive is is preferablyfrom preferably from 0.07 0.07 to to 1 1

kg, kg, and morepreferably and more preferablyfrom from0.07 0.07toto0.2 0.2kg. kg.When Whenthethe mass mass of the of the explosive explosive is is

not less not less than than 0.07 0.07 kg, kg, nanodiamond productivityincreases. nanodiamond productivity increases.

4 4 11786948_1 (GHMatters) 11786948_1 (GHMatters) P112226.AU P112226.AU

[0024]

[0024]

A mixtureofoftrinitrotoluene A mixture trinitrotoluene (TNT) andcyclotrimethylenetrinitramine, (TNT) and cyclotrimethylenetrinitramine, i.e., hexogen i.e., hexogen (RDX), canbebeused (RDX), can usedfor forthe theexplosive. explosive. The Themass mass ratio(TNT/RDX) ratio (TNT/RDX) of TNT of andRDX TNT and RDX is, is, forfor example, example, in in a range a range from from 40/60 40/60 to 60/40. to 60/40.

55 [0025]

[0025] The particle diameter The particle diameter of of the the explosive explosive is is preferably from from 45 45 to to 2360 2360µm, pm, morepreferably more preferably from from4545toto1700 1700 pm, µm, andand stillmore still more preferably preferably from from 75 90 75 to to 90 pm. With µm. Withthe themanufacturing manufacturing method method according according to antoembodiment an embodiment of the of the present present

invention, it invention, it isispossible possibletotoproduce producenanodiamonds havinga asmall nanodiamonds having smallparticle particle 10 diameter 10 diameter and and a large a large specific specific surface surface area, area, even even when when the the explosive explosive having having a a particle diameter particle diameter of of 45 45 pm µm or or greater, greater, as described as described above, above, is is used. used. Note that Note the that the particle particle diameter of the diameter of the explosive explosive can be measured measuredbybyusing usinga asmall smallangle angleX-ray X-ray scattering measurement scattering method measurement method sieving sieving method(%). method (%).

[0026]

[0026]

15 15 The pressure during The pressure duringthe the detonation detonationis, is, for for example, from1818toto35.4 example, from 35.4GPa, GPa, preferably from from 24.4 24.4to to 29.3 29.3 GPa, GPa,and andmore more preferably preferably from from 24.4 24.4 to 25.5 to 25.5 GPa. GPa.

Whenthe When thepressure pressureisisgreater greater than than or or equal equal to to 18 18 GPa, GPa,graphitization graphitization on onthe the surface of surface of the the produced nanodiamond produced nanodiamond crude crude product product becomes becomes slower, slower, and and thus thus the nanodiamond the content nanodiamond content tends tends to to increase. increase.

20 [0027] 20 [0027] In In the the producing nanodiamonds, producing nanodiamonds, subsequently subsequently the the container container and and the the

content therein content therein are are left leftfor forapproximately approximately 24 hours at room hours at temperature,and room temperature, and thus, are thus, are cooled. cooled. After After the the cooling, cooling,the thenanodiamond crudeproduct nanodiamond crude product(including (including soot and soot the nanodiamond and the nanodiamond aggregates aggregates produced produced as described as described above), above), whichwhich is is 25 deposited 25 deposited on the on the inner inner wall wall of the of the container, container, is is scraped scraped with with a spatula,whereby a spatula, whereby the nanodiamond the crude nanodiamond crude product product is is collected.ByBy collected. thethe detonation detonation method method

described above, described above, the the crude crude product productofofnanodiamond nanodiamond particles particles cancan be be obtained. obtained.

Furthermore, by Furthermore, byimplementing implementingthethe producing producing of nanodiamonds of nanodiamonds described described above above several times, several times, if ifnecessary, necessary, aadesired desiredamount of the amount of the nanodiamond crude nanodiamond crude product product

30 cancan 30 bebeobtained. obtained.

[0028]

[0028]

The nanodiamond The nanodiamond content content in the in the nanodiamond nanodiamond crudecrude product product obtained obtained by by the producing the nanodiamonds producing nanodiamonds is preferably is preferably from from 10 55 10 to to 55 mass%, mass%, more more preferably from preferably from 1313toto 50 50 mass%, mass%,andand stillmore still morepreferably preferablyfrom from 15 15 to to 40 40

35 mass%. 35 mass%. With With thethe manufacturingmethod manufacturing method accordingtotoan according an embodiment embodimentofofthe the present invention, invention, nanodiamonds nanodiamonds having having a small a small median median diameter diameter and aand a large large

specific surface specific surface area area can can be be produced, and aa nanodiamond produced, and nanodiamond crude crude product product having having

5 5 11786948_1 (GHMatters) 11786948_1 (GHMatters) P112226.AU P112226.AU

a nanodiamond a content nanodiamond content of of 10 10 mass% mass% or greater or greater can can be obtained, be obtained, whereby whereby

excellent production excellent efficiency is production efficiency is achieved. achieved.

[0029]

[0029]

Acid-Treating Acid-Treating

5 5 In In acid-treating, strongacid acid-treating, aastrong acidisisallowed allowedtotoact actonona a nanodiamond crude nanodiamond crude

product, i.e., product, i.e., a araw rawmaterial, material,ininananaqueous aqueous solvent, solvent,for forexample, example, to toremove remove

metal oxides. metal oxides. The Thenanodiamond nanodiamond crude crude product product obtained obtained by a by a detonation detonation method method

is prone is prone to to include include metal metal oxide, oxide, and this metal and this metal oxide is an oxide is an oxide oxide of of metals, metals, such such

as Fe, as Fe, Co, Co,ororNi, Ni,derived derived fromfrom the container the container or the or theused like likein used in the detonation the detonation

10 method. 10 method. The The metaloxide metal oxidecan canbe be dissolved dissolved and and removed removed from from the the nanodiamond nanodiamond crude product crude product by byallowing allowinga astrong strongacid acidtoto act act thereon thereon (acid (acid treatment) treatment) in in an an aqueoussolvent, aqueous solvent, for for example. example.The Thestrong strongacid acidused usedininthe theacid acidtreatment treatmentisis preferably aa mineral preferably mineral acid, acid, and and examples examplesthereof thereofinclude includehydrochloric hydrochloricacid, acid, hydrofluoricacid, hydrofluoric acid, sulfuric sulfuric acid, acid, nitric nitric acid, acid, and regia. and aqua aqua regia. A kind A single single of kind the of the 15 strong 15 strong acid acid maymay be used, be used, or two or two or more or more kindskinds of strong of the the strong acidsacids mayused. may be be used. The concentration The concentrationofofthe the strong strong acid acid used usedinin the the acid acid treatment treatment is, is, for for example, example,

from 11 to from to 50 50 mass%. mass%.The The acid acid treatment treatment temperature temperature is from is from 70 150°C, 70 to to 150°C, for for example. The example. Theduration durationofofthe theacid acidtreatment treatmentis, is, for for example, example, from from0.1 0.1toto2424 hours. Furthermore, hours. Furthermore, the the acid acid treatment treatment can canbebeperformed performed under under reduced reduced

20 pressure, 20 pressure, at at atmospheric atmospheric pressure, pressure, or under or under pressurization. pressurization. After After such such acid acid

treatment, the treatment, the solid solid content content (including (including nanodiamond aggregates) nanodiamond aggregates) is is washed washed with with

water by decantation, water by decantation, for for example. example.Washing Washingof of thethe solidcontent solid contentbybydecantation decantation is preferably is repeated preferably repeated until until the the pHtheofprecipitate pH of the precipitate solution solution reaches reaches 2 to 2 to 3, for 3, for example. When example. Whenthethe content content amount amount of metal of metal oxide oxide in the in the nanodiamond nanodiamond crude crude 25 product 25 product obtained obtained by the by the detonation detonation method method is small, is small, the acid the acid treatment treatment such such as as that described that described above maybebeomitted. above may omitted.

[0030]

[0030]

Oxidizing Oxidizing

Oxidizing isis performed Oxidizing performedtotoremove remove graphitefrom graphite from a nanodiamond a nanodiamond crudecrude

30 product 30 product by using by using an oxidizing an oxidizing agent. agent. A nanodiamond A nanodiamond crude product crude product obtained obtained by by a detonation a detonation method methodcontains containsgraphite, graphite,and andthe thegraphite graphiteisis derived derived from fromcarbon carbon that did that did not not form nanodiamond form nanodiamond crystalsfrom crystals from among among the the carbons carbons released released whenwhen

the explosive the used underwent explosive used underwentpartially partiallyincomplete incompletecombustion. combustion. ForFor example, example, an an oxidizing agent oxidizing agent can can be be allowed allowedtotoact, act, in in an aqueoussolvent, an aqueous solvent, on on the the 35 nanodiamond 35 nanodiamond crude crude product product which which is subjected is subjected to the to thetreatment acid acid treatment described described

above, thereby above, thereby removing removingthethegraphite. graphite.Furthermore, Furthermore,an an oxidizing oxidizing agent agent cancan be be allowed to allowed to act act on on the the nanodiamond nanodiamond crude crude product, product, whereby whereby an an

6 6 11786948_1 (GHMatters) 11786948_1 (GHMatters) P112226.AU P112226.AU

oxygen-containinggroup, oxygen-containing group,such such as as a acarboxyl carboxyl group group or or a hydroxyl a hydroxyl group, group, can can be be introduced to introduced to surfaces surfaces of of the the nanodiamonds. nanodiamonds.

[0031]

[0031]

Examples Examples ofofthe theoxidizing oxidizingagent agentused usedininthe theoxidation oxidationtreatment treatmentinclude include 55 chromic chromic acid, acid, chromic chromic anhydride, anhydride, dichromic dichromic acid, acid, permanganic permanganic acid, perchloric acid, perchloric

acid, nitric acid, nitric acid, acid, and andmixtures mixtures thereof, thereof, a mixed a mixed acid ofacid of atone at least least acidone acid selected selected therefromandand therefrom another another acid acid (for example, (for example, sulfuricsulfuric acid), acid), and saltsand salts thereof. thereof. Among these,a amixed Among these, mixed acid acid (in(in particular, aamixed particular, mixedacid acidofofsulfuric sulfuric acid acid and and nitric acid) nitric acid)isispreferably preferablyused usedsince sincesuch sucha amixed mixed acid acid is is environmentally environmentally

10 friendly 10 friendly andand exhibits exhibits excellent excellent performance performance in oxidizing in oxidizing and and removing removing graphite. graphite.

[0032]

[0032]

The mixture The mixture ratio ratio of sulfuric of sulfuric acid acid to nitric to nitric acid acid (the former/the (the former/the latter, latter,

mass ratio) mass ratio) in in the the above-described mixedacid above-described mixed acidisispreferably, preferably, for for example, example, fromfrom 60/40toto95/5, 60/40 95/5,since since when when the mixture the mixture ratio ratio is is inrange, in that that range, it is possible it is possible to to 15 efficiently 15 efficientlyoxidize oxidizeandand remove remove graphite graphite at, at, forfor example, example, a temperature a temperature of 1300 of 130°C C or higher or higher (particularly (particularly preferably preferably 150 0 or higher, 150°CC or higher, and with the and with the upper upper limit limit being 200 0 C,for being 200°C, for example), example),even evenunder under approximately approximately atmospheric atmospheric pressure pressure (for (for

example, from example, from0.5 0.5toto22atm). atm). The Thelower lowerlimit limitofofthe themixture mixtureratio ratio is is preferably preferably 65/35, and 65/35, and more morepreferably preferably70/30. 70/30.The Theupper upper limitofofthe limit themixture mixtureratio ratioisis 20 preferably 20 preferably 90/10, 90/10, more more preferably preferably 85/15, 85/15, and still and still moremore preferably preferably 80/20. 80/20. WhenWhen

the mixing the ratio is mixing ratio is not not less lessthan than60/40, 60/40,the thereaction reactiontemperature temperature becomes, for becomes, for

example, 120 0Cororhigher example, 120°C higherunder under approximately approximately atmospheric atmospheric pressure, pressure, sincesince

sulfuric acid sulfuric acidhaving having a high a high boiling boiling pointpoint is contained is contained in a amount. in a larger larger amount. Therefore, efficiency Therefore, efficiency in in graphite graphite removal tendstoto be removal tends be improved. improved.When Whenthethe

25 mixing 25 mixing ratio ratio is than is less less orthan or toequal equal 95/5,tonitric 95/5,acid nitric thatacid thatcontributes greatly greatly contributes to to oxidationofofgraphite oxidation graphite is contained is contained in a larger in a larger amount, amount, and thusand thus efficiency efficiency in in graphite removal graphite removal tends tendstoto be be improved. improved.

[0033]

[0033]

The amountofofuse The amount useofofananoxidizing oxidizingagent agent(in(inparticular, particular, the the mixed mixedacid acid 30 described 30 described above) above) is, is, forfor example, example, fromfrom 10 to1050 to parts 50 parts by mass, by mass, preferably preferably from from

15 to 15 to 40 40 parts parts by by mass, and more mass, and morepreferably preferablyfrom from2020to to4040parts partsbybymass, mass,based based on 11 part on part by mass of by mass of the the nanodiamond nanodiamond crude crude product. product. In In addition,thethe addition, amount amount of of use ofsulfuric use of sulfuricacid acidin in the the mixed mixed acid acid is, example, is, for for example, from from 5 to 5 to 48 48 parts by parts by

mass, preferably mass, preferably from from1010toto3535parts parts by bymass, mass,and andmore more preferably preferably from from 15 15 to to 35 30 30 35 parts parts by by mass, mass, based based on 1onpart 1 part by mass by mass of the of the nanodiamond nanodiamond crude crude product. product. In In addition, the addition, theamount amount of use of use of nitric of nitric acid acid inmixed in the the mixed acid is,acid for is, for example, example, from from 2 to 2 to 20 20 parts parts by by mass, mass, preferably from 44 to preferably from to 10 10 parts parts by by mass, mass, and andmore more

7 7 11786948_1 (GHMatters) 11786948_1 (GHMatters) P112226.AU P112226.AU

from 55 to preferably from preferably to 88 parts parts by by mass, based onon1 1part mass, based part by massofofthe by mass the nanodiamond nanodiamond crude crude product. product.

[0034]

[0034]

Furthermore, whenthethemixed Furthermore, when mixed is is acid acid used used as as thethe oxidizing oxidizing agent,a a agent,

55 catalyst catalyst maymay be used be used together together withwith the the mixed mixed acid.acid. WhenWhen the catalyst the catalyst is used, is used,

the removal the efficiency of removal efficiency of graphite graphite can can be be further further improved. improved.Examples Examplesof of thethe

catalyst include catalyst includecopper copper carbonate carbonate (II), (II), etc. amount etc. The The amount of use ofof use the of the is, catalyst catalyst is, for example, for fromabout example, from about0.01 0.01totoabout about1010parts parts by bymass massper per100 100parts partsbybymass mass of of

the nanodiamond the crude nanodiamond crude product. product.

10 [0035] 10 [0035] The oxidationtreatment The oxidation treatmenttemperature temperatureis,is,for for example, example,from from100100 to to 200°C. 200°C.

The duration The duration ofofthe the oxidation oxidation treatment treatment is, is, for for example, from1 1to example, from to 24 24 hours. hours. The The oxidation treatment oxidation treatment can can be be performed performedunder under reduced reduced pressure, pressure, at at atmospheric atmospheric

pressure, pressure, ororunder under pressurization. pressurization.

[0036] 15 [0036] 15 Alkali and Hydrogen Alkali and HydrogenPeroxide-Treating Peroxide-Treating In In aa case case where metal oxides where metal oxidesstill still remain in the remain in the nanodiamonds even nanodiamonds even after after

the above-described the acid-treating, the above-described acid-treating, the nanodiamonds nanodiamonds areare in in theform the form of of

aggregates (secondary aggregates (secondaryparticles) particles) in in which whichprimary primaryparticles particles interact interact very very 20 strongly 20 strongly with with each each other other and and aggregate. aggregate. In this In this case, case, an an alkaliandand alkali hydrogen hydrogen

peroxide may peroxide maybebeallowed allowed to to actononthe act thenanodiamonds nanodiamonds in aqueous in an an aqueous solvent. solvent. As As a result, a result,the themetal metaloxides oxides remaining in the remaining in the nanodiamonds canbebe nanodiamonds can removed, removed, and and

separation of separation of the the primary particles from primary particles the aggregates from the aggregates can can be bepromoted. promoted. Examplesofofthe Examples thealkali alkali used used inin this this treatment include include sodium sodiumhydroxide, hydroxide, 25 ammonia, 25 ammonia, and potassium and potassium hydroxide. hydroxide. In alkali In alkali and hydrogen and hydrogen peroxide peroxide treatment, treatment,

the concentration the of the concentration of the alkali alkali is, is,for example, for example,from from 0.1 0.1 to to 10 10 mass%, the mass%, the

concentration of concentration of hydrogen hydrogenperoxide peroxideis,is,for for example, example,from from 1 to15 15mass%, 1 to mass%, the the

treatment temperature treatment temperatureis, is, for for example, from4040toto100°C, example, from 100°C,andand theduration the durationforfor the treatment the is, for treatment is, forexample, example, from 0.5 to from 0.5 to 55 hours. hours. Furthermore, the alkali Furthermore, the alkali and and

30 hydrogen 30 hydrogen peroxide peroxide treatment treatment can can be be performed performed under reduced under reduced pressure, pressure, at at atmosphericpressure, atmospheric pressure, ororunder underpressurization. pressurization.

[0037]

[0037]

Drying Drying After the alkali After the alkali and and hydrogen peroxide-treating, drying hydrogen peroxide-treating, dryingis is preferably preferably 35 performed. 35 performed. For For example, example, by using by using a spray a spray drying drying apparatus, apparatus, an evaporator, an evaporator, etc., etc.,

the liquid the liquid content content is isevaporated evaporated from the nanodiamond-containing from the nanodiamond-containing solution solution

obtained through obtained throughthe the alkali alkali and and hydrogen hydrogenperoxide-treating, peroxide-treating,and andthen thenthe the resultingresidual resulting residualsolid solid content content is dried is dried by being by being heated heated andin dried and dried in a drying a drying

8 8 11786948_1 (GHMatters) 11786948_1 (GHMatters) P112226.AU P112226.AU oven. The oven. temperatureduring The temperature duringthethedrying dryingbybyheating heating is,is,for forexample, example,from 40 40 from to to 2019250113 15 Oct 2019

150°C. Through 150°C. Throughthe thedrying, drying,powdery powdery nanodiamond nanodiamond aggregates aggregates (nanodiamond (nanodiamond

particle aggregates) can particle aggregates) can be obtained. be obtained.

[0038]

[0038]

55 Oxygen-oxidizing Oxygen-oxidizing After the purifying, After the purifying, the the nanodiamond powder nanodiamond powder may may be subject be subject to to

oxygen-oxidizingbybybeing oxygen-oxidizing beingheated heated in in anan atmosphere atmosphere of gas of gas containing containing oxygen oxygen

using using aa gas gas atmosphere atmospherefurnace. furnace.Specifically, Specifically, in in the the oxygen-oxidizing, oxygen-oxidizing, the the nanodiamond nanodiamond powder powder is placed is placed in the in the gasgas atmosphere atmosphere furnace, furnace, an an 10 10 oxygen-containinggas oxygen-containing gasisisfed fedinto into or or passed passed through throughthe thefurnace, furnace, the theinside inside of of the furnace the is heated furnace is heated until until reaching reaching aa temperature, temperature, at at which which aa temperature temperature

condition set condition set as as the the heating heating temperature is satisfied, temperature is satisfied,whereby whereby the the oxygen oxygen

oxidation treatment oxidation treatment is is performed. Thetemperature performed. The temperaturecondition condition of of thisoxygen this oxygen oxidation treatment oxidation treatment is, is, for for example, from 250 example, from 250toto 500°C. 500°C.ToToachieve achievea negative a negative 15 zeta 15 zeta potentialforforthe potential thenanodiamond nanodiamond particles particles contained contained in ainnanodiamond a nanodiamond dispersion to dispersion to be be produced, the temperature produced, the temperatureofofthis this oxygen oxygenoxidation oxidationtreatment treatmentisis preferably relatively preferably relatively high, high, namely from400 namely from 400toto450°C, 450°C,for forexample. example. Additionally, the oxygen-containing Additionally, the gasused oxygen-containing gas usedininthe theoxygen-oxidizing oxygen-oxidizingmaymay be abe a

mixedgas mixed gascontaining, containing,ininaddition addition to to oxygen, oxygen,ananinert inert gas. gas. Examples Examplesofofthe theinert inert 20 gasgas 20 include include nitrogen, nitrogen, argon, argon, carbon carbon dioxide, dioxide, and and helium. helium. The oxygen The oxygen

concentration of concentration of the the mixed mixedgas gasis, is, for for example, from11 toto3535vol.%. example, from vol.%.

[0039]

[0039]

Hydrogenating Hydrogenating To achieve aa positive To achieve positive zeta zeta potential potential for for the the nanodiamond particles nanodiamond particles

25 contained 25 contained in ainnanodiamond a nanodiamond dispersion dispersion to be to be produced, produced, hydrogenating hydrogenating is is preferably performed preferably performedafter afterthe the oxygen-oxidizing oxygen-oxidizingdescribed described above. above. In In thethe

hydrogenating, the hydrogenating, the nanodiamond nanodiamond powder powder that that was was subjected subjected to to the the oxygen-oxidizingisisheated oxygen-oxidizing heatedusing usinga agas gasatmosphere atmosphere furnace,in inanan furnace, atmosphere atmosphere of of gas containing gas containing hydrogen. hydrogen.Specifically, Specifically, aa hydrogen-containing hydrogen-containinggasgas is isfed fedinto intooror 30 passed 30 passed through through the the gas gas atmosphere atmosphere furnace, furnace, in which in which the nanodiamond the nanodiamond powder powder is placed, is theinside placed, the insideofof the the furnace furnace is heated is heated untiluntil reaching reaching a temperature a temperature at at which which aatemperature temperaturecondition conditionset setasasthe the heating heatingtemperature temperatureisissatisfied, satisfied, whereby thehydrogenation whereby the hydrogenation treatment treatment is is performed. performed. TheThe temperature temperature condition condition

of this of this hydrogenation treatment is, hydrogenation treatment is, for for example, from 400 example, from 400toto800°C. 800°C. 35 Furthermore, 35 Furthermore, the the hydrogen-containing hydrogen-containing gas is gas that thatused is used in hydrogenating in the the hydrogenating may may be be aa mixed gascontaining, mixed gas containing, inin addition addition to to hydrogen, hydrogen, ananinert inert gas. gas. Examples Examplesofof the inert the inert gas gas include include nitrogen, nitrogen, argon, argon, carbon carbon dioxide, dioxide, and helium. The and helium. The hydrogen hydrogen concentration of concentration of the the mixed gasis, mixed gas is, for for example, from11 to example, from to 50 50 vol.%. vol.%. ToToachieve achievea a

99 11786948_1 (GHMatters) 11786948_1 (GHMatters) P112226.AU P112226.AU

negative zeta negative potential for zeta potential for the the nanodiamond particles contained nanodiamond particles containedininthe the nanodiamond nanodiamond dispersion dispersion to to bebe produced, produced, crushing, crushing, which which willwill be described be described

later, may later, may be be performed withoutperforming performed without performingthethe above-described above-described hydrogenating. hydrogenating.

[0040]

[0040]

55 By the manufacturing By the method manufacturingmethod according according to embodiment to an of theofpresent an embodiment the present invention, it invention, it isispossible possibletoto produce, produce,for forexample, example, nanodiamonds, theprimary nanodiamonds, the primary particles particles of of which which have have aa median mediandiameter diameterfrom from 4.04.0 to to 5.5nm, 5.5 nm, andand thethe specific specific 2 surface area surface area of of which is from which is 320toto 500 from 320 500m /g. Note m²/g. Notethat, that, the the nanodiamonds, nanodiamonds,thethe primary particles of primary particles of which havea amedian which have mediandiameter diameter from from 4.0 4.0 to to 5.55.5 nm,nm, andand the the 2 10 specific 10 specific surface surface area area of of which which is is from from 320320 to 500 to 500 m may m²/g /g may be referred be referred to herein to herein

as "the as "the nanodiamonds according nanodiamonds according to to thethe present present invention". invention".

[0041]

[0041]

The mediandiameter The median diameter (D50) (D50) of of primary primary particles particles of of thethe nanodiamonds nanodiamonds

according to according to an an embodiment embodiment of of thethe present present invention invention is is from from 4.04.0 to to 5.5nm, 5.5 nm, 15 preferably 15 preferably from from 4.2 4.2 to 5.2 to 5.2 nm,nm, and and moremore preferably preferably from from 4.45 to 4.4 to nm.5 Note nm. Note that that the median the diameterofofthe median diameter theprimary primaryparticles particlesofofnanodiamonds nanodiamondscan can be measured be measured

by by aa small small angle angle X-ray X-ray scattering scattering measurement measurement method method or aordynamic a dynamic lightlight

scattering method. scattering method.

[0042]

[0042]

20 20 The nanodiamonds The nanodiamonds according according to embodiment to an an embodiment of theofpresent the present invention invention

has aa specific specific surface surface area area of 2 has of 320 320 to to 500 500mm²/g, /g, preferably preferably from 340toto 450 from 340 m 2 /g, 450m²/g, and more and morepreferably preferablyfrom from350 350 to to 430 430 m 2 /g.Note m²/g. Note that that thethe specificsurface specific surfacearea areaofof the nanodiamonds the nanodiamonds cancan be be measured measured by the by the BET BET method. method. For example, For example, by by using using a redispersion a redispersion liquid liquid of of the the nanodiamonds, thespecific nanodiamonds, the specific surface surface area area of of the the 25 nanodiamonds 25 nanodiamonds cancan be be measured measured using using anan apparatus, "BELSORP-max" apparatus, "BELSORP-max" (available from (available BELJAPAN, from BEL JAPAN, Inc.). Inc.).

[0043]

[0043]

Even after being Even after being purified purified by by undergoing undergoingthe thepurifying, purifying,the the oxygen-oxidizing, the oxygen-oxidizing, thehydrogenating, hydrogenating,etc. etc.described describedabove, above,the thedetonation detonation 30 nanodiamonds 30 nanodiamonds have strong have strong tendency tendency to the to be in be inform the of form of aggregates aggregates (secondary (secondary

particles) in which particles) in whichthethe primary primary particles particles interact interact very strongly very strongly with with each othereach other

and aggregate. and aggregate. After After the the purifying, purifying, the the oxygen-oxidizing, orthe oxygen-oxidizing, or the hydrogenating, hydrogenating, the crushing the maybebeperformed crushing may performedto to cause cause more more primary primary particles particles to be to be separated separated

from the from the aggregates. aggregates. Specifically, Specifically, first, first,nanodiamonds that have nanodiamonds that have undergone undergonethethe 35 oxygen-oxidizing 35 oxygen-oxidizing or subsequent or subsequent hydrogenating hydrogenating are suspended are suspended in pure in puretowater water to prepare prepare aa slurry slurry containing nanodiamonds. nanodiamonds.In In preparing preparing thethe slurry, slurry,

centrifugation may centrifugation becarried may be carried out out to to remove removerelatively relatively large large aggregates aggregates from fromthe the nanodiamond nanodiamond suspension, suspension, or or ultrasonic ultrasonic treatment treatment maymay be performed be performed on on the the

10 10 11786948_1 (GHMatters) 11786948_1 (GHMatters) P112226.AU P112226.AU

nanodiamond nanodiamond suspension. suspension. TheThe slurry slurry is then is then subjected subjected to to a wet a wet crushing crushing

treatment. The treatment. The crushing crushingtreatment treatmentcan canbebeperformed performed using, using, forfor example, example, a high a high

shearing mixer, shearing mixer, aa high high shear shear mixer, mixer, aa homomixer, homomixer,a aball ballmill, mill, aa bead beadmill, mill, aa high high pressure homogenizer,ananultrasonic pressure homogenizer, ultrasonichomogenizer, homogenizer,or or a colloid a colloid mill.The mill. The 55 crushing crushing treatment treatment may may also also be performed be performed by combining by combining these. these. From From the the viewpoint viewpoint of of efficiency, efficiency, a bead a bead mill mill is preferably is preferably used. used.

[0044]

[0044]

A beadmill, A bead mill,which which is a isgrinding a grinding devicedevice or a disperser, or a disperser, is provided is provided with, with, for example, for example,a cylindrical a cylindrical millmill container, container, a rotor a rotor pin, apin, a centrifugation centrifugation

10 mechanism, 10 mechanism, a rawa material raw material tank,tank, and aand a pump. pump. The pin The rotor rotorhas pinanhas an axial axial centercenter

servingalso serving alsoasasanan axial axial center center of the of the mill mill container, container, and isand is configured configured to be to be rotatableatathigh rotatable highspeeds speeds within within the mill the mill container. container. The centrifugation The centrifugation

mechanism mechanism is isdisposed disposedat atananupper upperpart partinside insidethe themill millcontainer. container. In In bead bead milling using milling using aa bead mill in bead mill in the the crushing, crushing, the the slurry slurry (including (including nanodiamond nanodiamond

15 aggregates) 15 aggregates) is charged is charged as raw as a a raw material material from from the the raw raw material material tanktank intointo a lower a lower

part of the part of the mill millcontainer containerby by the the action action ofpump, of the the pump, in awhere in a state statethe where insidethe inside

of the of the mill millcontainer containeris is filledwith filled with beads beads androtor and the the rotor pin ofpin the of themill bead bead mill stirs stirs the beads. the beads. The slurry passes The slurry passes through through the the beads, beads, which whichare areunder underhigh-speed high-speed stirring in stirring in the the mill millcontainer, container,andand reaches reaches the upper the upper part ofpart the of the of inside inside of the the mill mill 20 container. 20 container. In In thisprocess, this process,the thenanodiamond nanodiamond aggregates aggregates contained contained in slurry in the the slurry are subjected are to action subjected to action of of grinding grinding or or dispersion dispersion through contact with through contact the with the

vigorously movingbeads. vigorously moving beads.AsAs a result,crushing a result, crushingofofthe thenanodiamond nanodiamond aggregates aggregates

(secondary particles) (secondary particles) into into primary particles proceeds. primary particles proceeds. The slurry and The slurry and beads beads that that have reached have reachedthe thecentrifugation centrifugation mechanism mechanismat at thethe upper upper part part in in themill the mill 25 container 25 container areare subjected subjected to centrifugation to centrifugation that that is isbased basedonon differencesin inspecific differences specific gravity by gravity the centrifugation by the centrifugation mechanism being mechanism being in in operation.The operation. The beads beads remain remain

in the in millcontainer, the mill container,andand thethe slurry slurry is discharged is discharged out ofout the of thecontainer mill mill container via a via a hollowline hollow line that that is is slidably slidably coupled coupled to to the the centrifugation centrifugationmechanism. The mechanism. The

discharged slurry discharged slurry is is returned returned to to the the raw raw material material tank, tank, and and then then pumped back pumped back

30 intointo 30 thethe mill mill container container by by thethe actionofof action thepump the pump (circulationoperation). (circulation operation).InInsuch such bead milling, zirconia bead milling, zirconia beads, beads, for for example, are used example, are used asas crushing crushingmedia, media,and andthe the bead diameteris, bead diameter is, for for example, from1515toto500 example, from 500µm. pm.TheThe amount amount (apparent (apparent

volume) ofbeads volume) of beadsused usedtotofill fill the the mill mill container container is, is,for forexample, example, from from 50 50 to to 80% 80%

of the of the capacity capacityofof the the mill mill container. container. The circumferential The circumferential speed ofspeed of the the rotor pin rotor pin 35 is,is,forforexample, 35 example, from from 8 to 8 to 12 12 m/minute. m/minute. The The amount amount of slurry of slurry to betocirculated be circulated is, is, for example, for from200 example, from 200toto600 600ml, ml,and andthetheflow flowrate rateofofthe theslurry slurry is, is, for for example, example,

from 55 to from to 15 15 L/hour. L/hour. Furthermore, Furthermore,the theduration durationfor fortreatment treatment(circulation (circulation operation time) operation time) is, is, for forexample, example, from 30 to from 30 to 300 300 minutes. minutes. In In the the crushing, crushing, instead instead

11 11 11786948_1(GHMaters) 11786948_1 (GHMatters) P112226.AU P112226.AU

of aa continuous of bead mill continuous bead mill as as described described above, above,a abatch-type batch-typebead beadmill millmay may be be

used. used.

[0045]

[0045]

By performingthe By performing thecrushing, crushing,a ananodiamond nanodiamond dispersion, dispersion, in which in which

55 colloidal colloidal nanodiamond nanodiamond primary primary particles particles are dispersed, are dispersed, canobtained. can be be obtained.

[0046]

[0046]

After undergoing After undergoingthe thecrushing, crushing,the the slurry slurry may maybebesubjected subjectedtotoa a classificationoperation classification operationto to remove remove coarsecoarse particles. particles. For example, For example, a classifier a classifier can can be used to be used to remove removecoarse coarseparticles particles from fromthe theslurry slurry through througha aclassification classification 10 operation 10 operation that that uses uses centrifugation.AsAs centrifugation. a result,a ablack a result, blacktransparent transparentnanodiamond nanodiamond dispersion, in dispersion, in which primary particles which primary particles of of nanodiamonds nanodiamonds areare dispersed dispersed as as colloidal particles, colloidal particles,can canbe be obtained. obtained.

[0047]

[0047]

The nanodiamonds The nanodiamonds that that have have undergone undergone the crushing, the crushing, or the or the

15 nanodiamonds 15 nanodiamonds that that have have undergone undergone the crushing the crushing and theand the classification classification operation operation

maybebesubjected may subjected to drying. to drying. Indrying, In the the drying, specifically, specifically, the dispersion the dispersion

containing nanodiamonds containing nanodiamonds is is subjected subjected to to thedrying the drying treatment treatment thereby thereby

producingaadry producing drypowder powderof of nanodiamonds. nanodiamonds. Examples Examples of theofdrying the drying treatment treatment

include spray include spray drying drying performed performedusing usinga spray a spraydrying drying apparatus apparatus or or evaporating evaporating

20 to to 20 dryness dryness by by using using an evaporator. an evaporator.

[0048]

[0048]

The nanodiamond The nanodiamond dispersion dispersion contains contains nanodiamond nanodiamond particles particles and and

dispersion medium. dispersion medium.The The nanodiamond nanodiamond particles particles contained contained in nanodiamond in the the nanodiamond dispersion are dispersion are nanodiamond primary nanodiamond primary particles particles or or nanodiamond nanodiamond secondary secondary

25 particles 25 particlesderived derived from from nanodiamonds nanodiamonds obtained obtained by theby the manufacturing manufacturing method method according to according to an an embodiment embodiment of of thethe present present invention,andand invention, areare dispersed dispersed as as

colloidal particles colloidal particles separated separated from from each other in each other in the the dispersion dispersion medium. The medium. The

mediandiameter median diameterofofthe thenanodiamond nanodiamond particles particles is, is, forforexample, example, 60 60 nm nm or less, or less,

preferably 30 preferably 30 nm nmororless, less, more more preferably preferably 2828nmnmororless, less, still still more more preferably 25 preferably 25

30 nm nm 30 or less, or less, even even more more preferably preferably 22ornm 22 nm or less, less, and particularly and particularly preferably preferably 20 20 nmoror less. nm less. The mediandiameter The median diameterof of thenanodiamond the nanodiamond primary primary particles particles included included

in the in the nanodiamond particlesis, nanodiamond particles is, for for example, 5.5 nm example, 5.5 nmororless, less, preferably preferably 5.2 5.2 nm nm or less, or less,and and more preferably 55 nm more preferably nmororless. less. For For example, example, when when nanodiamond nanodiamond

dispersion is dispersion is used used as as aa material material for for adding adding or or supplying supplying nanodiamonds nanodiamonds to to a a 35 transparent 35 transparent resin resin or or thethe likewhen like when producing producing a nanodiamond-containing a nanodiamond-containing

transparent material, transparent material, the the nanodiamond particleshaving nanodiamond particles havinga asmaller smallermedian median diameter tends diameter tends to to be be preferable, preferable, from from the the viewpoint viewpointofofachieving achievinghigh high transparency of transparency of the the transparent transparent material. material. On On the the other other hand, hand, the the lower lower limit limit of of

12 12 11786948_1 (GHMatters) 11786948_1 (GHMatters) P112226.AU P112226.AU

the median the diameterofofthe median diameter thenanodiamond nanodiamond particles particles is is 1 nm, 1 nm, forfor example. example. TheThe

mediandiameter median diameterininthe thedispersion dispersioncan canbebemeasured measuredby by a dynamic a dynamic light light

scattering method. scattering method.

[0049]

[0049]

55 The specific surface The specific surface area area of of the the nanodiamond particlesininthe nanodiamond particles the nanodiamond nanodiamond dispersion dispersion is is preferablyfrom preferably from 320320 to 500 to 500 m 2 /g, m²/g, moremore preferably preferably

from 340 from 340toto 450 m 2 /g,and 450m²/g, andstill still more preferably from more preferably from350 350to to430 m 2/g.Note 430m²/g. Note that that

the specific the specific surface surface area area of of the thenanodiamonds canbebemeasured nanodiamonds can measured by by thethe BETBET

method. For method. Forexample, example,byby using using a redispersion a redispersion liquidofofthe liquid thenanodiamonds, nanodiamonds,the the

10 specific 10 specific surface surface area area of of thenanodiamonds the nanodiamonds canmeasured can be be measured using using an apparatus, an apparatus,

BELSORP-max BELSORP-max (availablefrom (available fromBEL BEL JAPAN, JAPAN, Inc.). Inc.).

[0050]

[0050]

The dispersion medium The dispersion medium contained contained in the in the nanodiamond nanodiamond dispersion dispersion is a is a

medium medium forappropriately for appropriatelydispersing dispersingnanodiamond nanodiamond particles particles in the in the nanodiamond nanodiamond

15 dispersion. 15 dispersion. TheThe dispersion dispersion medium medium is preferably is preferably a solvent a solvent with with whichwhich the the nanodiamonds nanodiamonds cancan be be dissolved, dissolved, andand examples examples of the of the dispersion dispersion medium medium

include water, include water, methanol, methanol, ethanol, ethanol, ethylene ethylene glycol, glycol, dimethyl dimethylsulfoxide, sulfoxide, and and N-methylpyrrolidone. Only N-methylpyrrolidone. Only oneone kind kind of dispersion of dispersion medium medium may may be be used, used, or twoor two

or more or kindsof more kinds ofdispersion dispersion media mediamay may be be used. used. From From the the viewpoint viewpoint of of the the 20 dispersibility 20 dispersibilityofof thenanodiamond the nanodiamond particles, particles, thethe dispersion dispersion medium medium is preferably is preferably

water or aa water-based water or dispersionmedium water-based dispersion medium containing containing 50 mass% 50 mass% or greater or greater of of water. water.

[0051]

[0051]

The nanodiamond The nanodiamond dispersions dispersions constituted constituted as as described described above above can can be used be used

25 as aas material 25 a material serving serving as as a nanodiamond a nanodiamond source source when when producing producing a composite a composite

material containing material containing nanodiamonds. nanodiamonds. Furthermore, Furthermore, by the by the manufacturing manufacturing method method

according to according to an an embodiment embodiment of of thethe present present invention, invention, it itisis possible possible to to manufacturenanodiamond manufacture nanodiamond particles particles that that cancan be be used used to prepare to prepare such such

nanodiamond nanodiamond dispersions, dispersions, forfor example. example.

30 [0052] 30 [0052] The manufacturingmethod The manufacturing method according according to embodiment to an an embodiment of theof the present present

invention includes invention includes producing producingnanodiamonds nanodiamonds by using by using a detonation a detonation method, method, and and in the in the producing nanodiamonds, producing nanodiamonds, an an explosive explosive is is detonated detonated in in a containerunder a container under a a condition where condition wherea aratio ratio of of volume volume ofofthe the container container toto mass massofofthe the explosive explosive[the

[the 35 volume 35 volume of the of the container container (m 3)/the (m³)/the massmass of explosive of the the explosive (kg)](kg)] is 10is or or less. 10 less. TheThe

detonation in detonation in the the manufacturing method manufacturing method according according to an to an embodiment embodiment of of the the present invention present invention is is characterized characterized in the in that thatabove-described the above-described ratio, ratio, i.e., the i.e., the

ratio of ratio of the the volume volume of the of the container container tomass to the the of mass the of the explosive explosive is set to isa small set to a small

13 13 11786948_1 (GHMatters) 11786948_1 (GHMatters) P112226.AU P112226.AU

value. value. With detonation being With detonation beingperformed performed under under thethe condition, condition, heat heat dissipation dissipation

after the after the detonation detonation becomes slower,and becomes slower, andthus thusgraphitization graphitization ononthe thesurface surfaceofof the resulting the resulting nanodiamond crude nanodiamond crude product product is is promoted. promoted. As As a result,thethediameter a result, diameter of the of the nanodiamond parts,i.e., nanodiamond parts, i.e., the the diameter of the diameter of the nanodiamond particles nanodiamond particles

55 obtained obtained after after thethe purifying,becomes purifying, becomes smaller, smaller, and and the the specific specific surface surface area area

increases. increases.

Examples Examples

[0053]

[0053]

10 10 Hereinafter, Hereinafter, embodiments embodiments of of thepresent the presentinvention inventionwill willbebedescribed describedinin moredetail more detail based based on onexamples, examples,but butthe thepresent presentinvention inventionisisnot notlimited limited by bythese these examples. examples.

[0054]

[0054]

Example 11 Example 15 15 Nanodiamonds Nanodiamonds and and nanodiamond nanodiamond dispersions dispersions were made made according wereaccording to the to the following process. following process. Producing Nanodiamonds Producing Nanodiamonds In In producing nanodiamonds, producing nanodiamonds, first,ananelectric first, electric detonator detonator was wasattached attachedtotoa a moldedexplosive, molded explosive,and andthen thenplaced placedinside insidea apressure-resistant pressure-resistantcontainer containerfor for 20 detonation, 20 detonation, and and the the container container was was sealed. sealed. The The container container was made was made from from iron, iron, 3 and the and the capacity capacity of of the the container was 0.2 m³. was 0.2 m . As As the the explosive, explosive, 0.2 0.2 kg kg of of aa mixture of mixture of TNT TNT and and RDX wasused. RDX was used. The The mass mass ratio ratio (TNT/RDX) of TNT (TNT/RDX) of TNTand and RDXininthe RDX theexplosive explosivewas was 60/40. 60/40. Next, Next, thethe electricdetonator electric detonatorwas was ignited,and ignited, and the explosive the was detonated explosive was detonatedininthe the container. container. Subsequently, Subsequently,the the container container and andits its 25 interior 25 interior were were leftstanding left standing for2424hours for hours at at room room temperature, temperature, and and werewere thereby thereby

cooled. After cooled. After the the cooling, cooling, aa nanodiamond crudeproduct nanodiamond crude product deposited deposited on the on the inner inner

wall of the wall of the container container (including soot and (including soot the nanodiamond and the particleaggregates nanodiamond particle aggregates produced produced bybythe thedetonation detonationmethod method described described above) above) was was scraped scraped by using by using a a spatula, thereby spatula, collecting the thereby collecting the nanodiamond crudeproduct. nanodiamond crude product. 30 [0055] 30 [0055] Acid-Treating Acid-Treating

Next, the Next, the nanodiamond nanodiamond crude crude product product obtained obtained by performing by performing the the producing ofnanodiamonds producing of nanodiamonds described described above above multiple multiple timestimes was subjected was subjected to an to an

acid treatment. acid treatment. Specifically, Specifically, aa slurry slurryobtained obtainedby by adding adding 66 L L of of 10 10 mass% mass%

35 hydrochloric 35 hydrochloric acidacid to 200 to 200 g ofg the of the nanodiamond nanodiamond crude crude product product was subjected was subjected to to heating treatment heating treatment for for 11 hour hour under under reflux reflux at at normal pressureconditions. normal pressure conditions. The The heating temperature heating temperature inin this this acid acid treatment was from treatment was from8585toto100°C. 100°C.Next, Next,after after cooling, the cooling, the solid solid content content (including (including nanodiamond aggregates nanodiamond aggregates andand soot) soot) waswas

14 14 11786948_1 (GHMatters) 11786948_1 (GHMatters) P112226.AU P112226.AU

washed withwater washed with waterbybydecantation. decantation.Washing Washing of the of the solid solid content content by by decantation decantation

was repeated until was repeated until the the pH pHof ofaa precipitate precipitate solution solution reached reached 22 from from the the low low pH pH side. side.

[0056]

[0056]

55 Oxidizing Oxidizing Oxidation treatment Oxidation treatmentwas wasthen thenperformed. performed. Specifically,a aslurry Specifically, slurrywas was formedbybyadding formed adding6 6L Lofofa a9898mass% mass% sulfuric sulfuric acid acid aqueous aqueous solution solution and and 1 L 1 ofL aof a 69 mass% 69 mass%nitric nitricacid acid aqueous aqueoussolution solutiontotothe theprecipitate precipitate solution solution (containing (containing nanodiamond nanodiamond aggregates) aggregates) obtained obtained through through decantation decantation after after the the acid acid treatment, treatment,

10 andand 10 subsequently, subsequently, the the slurry slurry waswas subjected subjected to heat to heat treatment treatment under under reflux reflux for for 48 48 hours at hours at normal pressure conditions. normal pressure conditions. The Theheating heatingtemperature temperaturein inthis thisoxidation oxidation treatment was treatment wasfrom from140 140toto160°C. 160°C. Next, Next, aftercooling, after cooling,the thesolid solidcontent content (including nanodiamond (including nanodiamond aggregates) aggregates) waswas washed washed with with waterwater by decantation. by decantation.

The initial The initial supernatant supernatant liquid liquid from from the the water water washing wascolored, washing was colored,and and 15 therefore 15 therefore thethe washing washing of the of the solid solid content content with with water water by decantation by decantation was was repeateduntil repeated untilthethesupernatant supernatant liquid liquid became became visuallyvisually clear. clear.

[0057]

[0057]

Drying Drying Next, the precipitate Next, the precipitate solution solution (including (including nanodiamond aggregates) nanodiamond aggregates)

20 obtained 20 obtained through through decantation decantation afterafter the the oxidation oxidation treatment treatment was was then then subjected subjected to to drying treatment drying and aa dried treatment and dried powder powderwas was obtained. obtained. As As a technique a technique forfor thethe

treatment, evaporation drying treatment, drying evaporation to to dryness byusing dryness by usingananevaporator evaporatorwas was adopted. In In adopted. this way, this way, the the nanodiamond powder nanodiamond powder of Example of Example 1 was1 obtained. was obtained.

[0058]

[0058]

25 Crushing 25 Crushing Treatment Treatment The crushingtreatment The crushing treatmentwas wasthen thenperformed. performed. Specifically,first, Specifically, first, 0.3 0.3 gg of of the nanodiamond the powder nanodiamond powder thatthat hadhad undergone undergone the drying, the drying, and 29.7 and 29.7 ml ofml of pure pure

water weremixed water were mixedinina a5050mlmlsample sample bottleto toobtain bottle obtaina aslurry. slurry. Next, Next,pHpHofofthe the slurry was slurry adjusted to was adjusted to 11 11 using using aa 3 3 mol/L sodiumhydroxide mol/L sodium hydroxide aqueous aqueous solution. solution.

30 As As 30 a result,30 30 a result, ml ml of of a slurryhaving a slurry having pH pH of of 11 11 andand containing containing 1 mass% 1 mass% of solid of solid

content was content was prepared. prepared. Next, Next,the theslurry slurry was wassubjected subjectedtotoultrasonic ultrasonic irradiation irradiation for 11 hour for hour using an ultrasonic using an ultrasonic irradiator irradiator (trade (tradename name Ultrasonic Cleaner AS-3, Ultrasonic Cleaner AS-3, available from available ASONE). from AS ONE). Subsequently, Subsequently, beadbead milling milling was was performed performed using using a a bead milling device bead milling device (trade (trade name nameParallel Parallel4-Tube 4-TubeSand Sand Grinder Grinder Model Model

35 LSG-4U-2L, 35 LSG-4U-2L, available available from Aimex from Aimex Co., Specifically, Co., Ltd.). Ltd.). Specifically, 30 ml 30 of ml the of the slurry slurry

after ultrasonic after ultrasonic irradiation, irradiation,and andzirconia zirconiabeads beadshaving having aadiameter diameter of of 30 30 pm were µm were

charged in charged in aa 100 100 ml ml vessel vessel (available (available from from Aimex Aimex Co.,Ltd.), Co., Ltd.),which whichwaswas thethe mill mill

container, and container, then the and then the vessel vessel was sealed. Then, was sealed. Then, the the device device was wasactuated actuatedtoto

15 15 11786948_1 (GHMatters) 11786948_1 (GHMatters) P112226.AU P112226.AU

2019 perform bead perform beadmilling. milling. InInthis this bead bead milling, milling, the the amount amountofofzirconia zirconia beads beadsthat that were chargedwas, were charged was,for forexample, example,33%33% of the of the capacity capacity of of thethe mill mill container,thethe container,

rotational speed rotational of the speed of the mill mill container container was 2570 rpm, was 2570 rpm,and andthe theduration durationofofthe the 2019250113 15 Oct

milling was milling was 11 hour. hour. 55 [0059]

[0059] Next, the Next, the slurry slurry or or suspension that had suspension that undergonethe had undergone theabove-described above-described crushing treatment crushing treatment was wassubjected subjectedtotocentrifugation centrifugationtreatment treatmentusing usinga acentrifuge centrifuge device. The device. The centrifugal centrifugal force force in in this this centrifugation centrifugationtreatment treatment was 20000xg, was 20000 xg, and and the duration the of the duration of the centrifugation centrifugation was 10 minutes. was 10 minutes. Next, Next, 1010mlmlofofsupernatant supernatantofof 10 thethe 10 nanodiamond-containing nanodiamond-containing solution solution thatbeen that had had subjected been subjected to to this this centrifugation treatment centrifugation was collected. treatment was collected. In In this this way, way, aa nanodiamond dispersion nanodiamond dispersion

of Example of Example 1,1,in in which whichthe thenanodiamonds nanodiamondsare are dispersed dispersed in pure in pure water, water, was was

obtained. obtained.

[0060]

[0060]

15 Examples 15 Examples 2 and 2 and 3 andComparative 3 and ComparativeExample Example 1 1 Nanodiamondcrude Nanodiamond crudeproducts, products, nanodiamond powders, and nanodiamond powders, and nanodiamond nanodiamond dispersions were dispersions were prepared preparedinin the the same samemanner manner as as in in Example Example 1 except 1 except that, that, in in the producing the nanodiamonds, producing nanodiamonds, containers containers having having volumes volumes as shown as shown in Table in Table 1 1 and explosives and explosives according accordingtotomasses massesasasshown shown in in Table Table 1 were 1 were used. used.

20 [0061] 20 [0061] The nanodiamond The nanodiamond crude crude products, products, nanodiamond nanodiamond powders, powders, and and nanodiamond nanodiamond dispersions dispersions obtained obtained in in Examples Examples and Comparative and Comparative Example Example were were evaluated as evaluated as follows. follows. The The results results are are shown in Table shown in Table 1.1.

[0062]

[0062]

25 1. Median 25 1. Median Diameter Diameter of Primary of Primary Particles Particles

For the obtained For the obtained nanodiamond nanodiamond powders powders after after the the drying, drying, the the small small angle angle

X-ray scattering measurement X-ray scattering measurement using using an an X-ray X-ray diffractometer diffractometer (trade (trade name name

SmartLab,available SmartLab, availablefrom fromRigaku Rigaku Corporation) Corporation) was was performed performed andprimary and the the primary particle particle diameters diameters of of the the nanodiamonds were nanodiamonds were estimated, estimated, forfor scatteringangles scattering angles 30 ranging 30 ranging fromfrom 1° 3°, 1° to to 3°, by using by using particle particle diameter diameter distribution distribution analysis analysis software software

(trade name (trade NANO-Solver, name NANO-Solver, available available fromfrom Rigaku Rigaku Corporation). Corporation). In theIn the estimate, it estimate, itwas was assumed that the assumed that the nanodiamond nanodiamond primary primary particles particles were were spherical spherical

andhad and hada aparticle particledensity density of 3.51 of 3.51 g/c g/c m³. m3 .

[0063]

[0063]

35 2. 2.Specific 35 Specific Surface Surface Area Area For the nanodiamond For the nanodiamond dispersions,thethespecific dispersions, specificsurface surfacearea areawas wasmeasured measured by using an by using an automatic automaticspecific specific surface surface area/pore area/pore distribution distribution measurement measurement apparatus (trade apparatus (trade name nameBELSORP-max, BELSORP-max, available available fromJAPAN, from BEL BEL Inc.). JAPAN, Inc.).

16 16 11786948_1 (GHMatters) 11786948_1 (GHMatters) P112226.AU P112226.AU

2019 [0064]

[0064]

3. Nanodiamond 3. Content Nanodiamond Content The nanodiamond The nanodiamond contents contents of the of the nanodiamond nanodiamond crude crude products products were were 2019250113 15 Oct

calculated according calculated according to to the the following following equation: equation: 55 Nanodiamond Nanodiamond content content [mass%]

[mass%] = mass = mass of of driedpowder dried powder after drying/mass after drying/mass of of nanodiamond nanodiamond crude crude product product after after producing producing nanodiamonds nanodiamonds X 100 x 100

[0065]

[0065]

Table 11 Table

(Table 1) (Table 1) Example Example Example Example Comparative Example Example Comparative 1 1 2 2 3 3 Example1 Example 1 3 Volume Volume ofofcontainer container(m³) (m ) 0.2 0.2 0.2 0.2 0.2 0.2 31 31

Mass ofexplosive Mass of explosive(kg) (kg) 0.2 0.2 0.1 0.1 0.7 0.7 1 1

Volume Volume ofofcontainer/Mass container/Massof of 11 2 2 3 3 31 31 explosive explosive

Median diameterofofprimary Median diameter primary 44 47 5.0 5.6 4.4 4.7 5.0 5.6 particles particles (nm) (nm)

Specific Surface Specific Surface Area (m 2/g) Area (m²/g) 423 423 385 385 360 360 311 311

Nanodiamond content (mass%) Nanodiamond content (mass%) 16.0 16.0 24.3 24.3 33.1 33.1 61.2 61.2

10 10

Reference SignsList Reference Signs List

[0066]

[0066]

S Producing S1 Producing nanodiamonds nanodiamonds S2 Acid-treating S2 Acid-treating 15 S3S3Oxidizing 15 Oxidizing S4 Alkali S4 Alkali and and hydrogen hydrogenperoxide-treating peroxide-treating S5 Drying S5 Drying

[0067]

[0067]

It It is is to to be understood be understood that,that, if prior if any any prior art publication art publication is referred to herein, is referred to herein,

20 20 suchsuch reference reference doesconstitute does not not constitute an admission an admission that thethat the publication publication formsof a part of forms a part

the common the general common general knowledge knowledge in the in theinart,Australia art, in Australia or anyorother any other country. country.

[0068]

[0068]

In In the the claims whichfollow claims which follow andand in the in the preceding preceding description description ofinvention, of the the invention, except where except wherethethecontext context requires requires otherwise otherwise due due to express to express language language or necessary or necessary

25 25 implication,thetheword implication, word"comprise" "comprise"or orvariations variations such such as as "comprises" or "comprising" "comprises" or "comprising"

is used is in an used in inclusive sense, an inclusive sense, i.e. i.e. to to specify specify the the presence ofthe presence of the stated stated features features but butnot not

17 17 11786948_1 (GHMatters) 11786948_1 (GHMatters) P112226.AU P112226.AU to preclude the presence or addition of further features in various embodiments of the 17 Jul 2025 invention. 21921716_1 (GHMatters) P112226.AU

It is to be understood that, if any prior art publication is referred to herein, such 5 reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country. 2019250113

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, 10 the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

18 21921716_1 (GHMatters) P112226.AU 17/07/2025

Claims (6)

1. Claims 17 Jul 2025

   [Claim 1] 21921716_1 (GHMatters) P112226.AU

   A method of manufacturing nanodiamonds, comprising producing nanodiamonds by detonating an explosive in a container under a condition where a ratio of volume of the container to mass of the explosive [the volume of the container (m 3 )/the mass of the explosive (kg)] is 1 to 10 and the volume of the 2019250113

   container is from 0.05 to 0.2 m 3 .
2. [Claim 2] The method of manufacturing nanodiamonds according to claim 1, wherein the mass of the explosive is from 0.07 to 1 kg.
3. [Claim 3] The method of manufacturing nanodiamonds according to any one of claims 1 or 2, wherein a nanodiamond content in a nanodiamond crude product obtained in the producing nanodiamonds is from 5 to 55 mass%.
4. [Claim 4] The method of manufacturing nanodiamonds according to any one of claims 1 to 3, wherein a particle diameter of the explosive is from 45 to 2360 µm.
5. [Claim 5] The method of manufacturing nanodiamonds according to any one of claims 1 to 4, wherein the explosive is a mixture of trinitrotoluene and cyclotrimethylenetrinitramine.
6. [Claim 6] Nanodiamonds comprising primary particles having a median diameter of 4.0 to 5.5 nm and a specific surface area from 320 to 500 m2 /g obtained by the method of manufacturing nanodiamonds according to any one of claims 1 to 5.

   19 21921716_1 (GHMatters) P112226.AU 17/07/2025