JP2011201720A - Nanodiamond, polymerizable composition containing the same, and resin, optical component and lens produced by polymerizing the composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide nanodiamond having a small and uniform particle size and free from re-aggregation thereafter and suitable as a material for optical components.SOLUTION: Nanodiamond containing a graphite phase, in which 95% or more of the particles have a particle diameter of not more than 1,000 nm measured by a dynamic light-scattering method, is purified by a sub-critical or supercritical treatment in a fluid where oxygen and water and/or alcohol are present together, and processed into fine particles.

Description

  The present invention relates to a nanodiamond obtained by removing a graphite phase from a nanodiamond having a graphite phase efficiently and sufficiently at a low cost, and then atomizing the nanodiamond and the use thereof.

  Nanodiamond has high hardness and is excellent in smoothness, so it is used as an abrasive or a lubricant. Nanodiamond also has a low dielectric constant and is excellent in electrical insulation, heat resistance, thermal conductivity, optical properties and biocompatibility, so it can be used in fields such as insulating materials for semiconductors and circuit boards, materials for optical components, etc. The use in is expected.

  A typical method for producing nanodiamond is an explosion method (a method in which an explosive containing carbon atoms is exploded and nanosized diamond is generated by an impact associated therewith). However, since the nanodiamond obtained by this method contains carbon impurities mainly composed of graphite, the original properties of diamond are hindered.

  Patent Document 1 describes a method of purifying a graphite phase-containing nanodiamond by treating it with supercritical water. However, in order to sufficiently remove the graphite phase by this method, a temperature of 700 to 800 ° C. and a pressure of 100 to 200 MPa are required, which are relatively close to the critical point of water (critical temperature 374 ° C., critical pressure 22.1 MPa). There is a problem that the temperature and pressure are not enough, and the cost of energy and equipment is high.

  Therefore, Non-Patent Document 1 describes a method of purifying a graphite phase-containing nanodiamond by oxidizing it with air under atmospheric pressure. However, in this method, oxygen does not sufficiently penetrate into the graphite phase at the grain boundary, so that only the graphite phase on the nanodiamond surface may be removed.

JP 2004-43265 A

Yury Gogotsi, 4 others, “Journal of the American Chemical Society”, 2006, 128, pp. 11635-11642

By the way, when nanodiamond is developed for use as a material for optical components, for example, in order to uniformly disperse in a transparent optical resin and to maintain the optical transparency of the resin after dispersion, nanodiamond is a particle. It is necessary that the diameters are uniform and not re-agglomerated. If the graphite phase cannot be removed sufficiently, even if the atomization process is performed, the diamond particle diameter obtained will not be uniform, and from the viewpoint of application to optical parts materials that require transparency, patent literature 1 and Non-Patent Document 1 are insufficient.
Furthermore, in the optical component material, from the viewpoint of requiring high light transmittance and low haze (cloudiness), the nanodiamond applied for this application is required to have a small particle size.
Accordingly, one object of the present invention is to provide a nanodiamond having a small particle size, uniform and non-re-aggregation suitable for use in optical component materials.
Another object of the present invention is to use the obtained finely divided nanodiamond for a material for optical parts.

  As a result of diligent research in view of the above object, the present inventor has found that the nanodiamond having a graphite phase is heated to a temperature not lower than the normal boiling point of the processing solvent in a fluid in which oxygen and a processing solvent comprising water and / or alcohol coexist. And the subcritical or supercritical treatment at a pressure of 1 atmosphere (gauge pressure) or more, the graphite phase can be removed efficiently and sufficiently at low cost, and the nanodiamond from which the graphite phase is removed It was discovered that nanodiamonds having a small particle size, uniform, and not re-aggregated can be obtained by atomizing the particles.

  That is, the nanodiamond of the present invention is obtained by converting a nanodiamond containing a graphite phase into a fluid in which oxygen and a processing solvent composed of water and / or alcohol coexist, at a temperature not lower than the normal boiling point of the processing solvent and at one atmospheric pressure (gauge). Pressure) at a pressure equal to or higher than that, subcritical treatment or supercritical treatment, and the nanodiamond is atomized.

  The nanodiamonds of the present invention are suitable as a material for optical parts that are particularly required to be transparent because they have small particle sizes, are uniform, and do not re-aggregate thereafter.

It is sectional drawing which shows the apparatus which manufactures a blend diamond.

The present invention will be described below.
The nanodiamond of the present invention contains the graphite phase and is subjected to the following treatments (A) and (B) on nanodiamond having a particle diameter of 95% or more determined by the dynamic light scattering method and 1,000 nm or less. Here are the lightened nanodiamonds obtained:
(A) In a fluid in which oxygen and a processing solvent comprising water and / or alcohol coexist, the nanodiamond is subcritically processed or supertreated at a temperature higher than the normal boiling point of the processing solvent and at a pressure higher than one atmospheric pressure (gauge pressure). Critical treatment, and (B) atomization treatment of the nanodiamond prepared in the treatment (A).

[Process (A)]
In the treatment (A), the graphite phase-containing nanodiamond is purified by subcritical treatment or supercritical treatment in a predetermined solvent in the presence of oxygen.

[1] Preparation of graphite phase-containing nanodiamond Graphite phase-containing nanodiamond to be purified in the treatment (A) is synthesized by an explosion method or the like. The graphite phase-containing nanodiamond may be as-synthesized crude diamond (blended diamond, hereinafter referred to as BD), or may be obtained by selectively oxidizing BD and then neutralizing with a base. Ultra-dispersed diamond (Ultra Dispersed Diamond, hereinafter referred to as UDD) from which a portion has been removed may be used, but UDD is preferred.

A method for producing BD and UDD by the explosion method is described in, for example, Japanese Patent Application Laid-Open No. 2006-239511.
Specifically, as shown in FIG. 1, an electric detonator 6 is installed in the body, and an explosive [eg, TNT (trinitrotoluene) / HMX (cyclotetramethylenetetranitramine) = 50/50 (mass ratio)] 5 If the steel pipe 4 with a single-sided plug containing steel is submerged in the ice water 1 in the pure titanium pressure vessel 2 and the steel pipe 4 is covered with the steel helmet 3 to explode the explosive, the ice water 1 BD is generated.

The manufacturing method of UDD is:
(1-1) BD is selected by pressurizing and heating in acid (concentrated nitric acid, concentrated sulfuric acid, a mixture of these, etc.) at a pressure of about 1.4 MPa and a temperature of about 150 to 180 ° C. for 10 to 30 minutes. Oxidative treatment,
(1-2) By subjecting the obtained dispersion to pressure heating at a pressure of about 1.8 MPa and a temperature of about 200 to 240 ° C., BD is subjected to primary oxidizing etching treatment,
(1-3) Further, by applying pressure and heating at a pressure of about 2.5 MPa and a temperature of about 230 to 250 ° C., the BD is subjected to secondary oxidizing etching treatment,
(1-4) The acid is neutralized by adding 1 to 1.5 equivalents of a base (ammonia etc.) of the acid to the obtained dispersion.
(1-5) Washing the obtained UDD with water,
(1-6) A step of centrifuging the obtained suspension.
The UDD dehydrated in the step (1-6) may be added with water to make a suspension, or dried to make a fine powder.

  The BD obtained by the explosion method and the UDD obtained by subjecting the BD to the above steps (1-1) to (1-6) have a particle diameter of 95% by volume or more and 1,000 nm or less. Is preferable, and it is preferable that particles having a particle diameter of 1,000 nm or more are not substantially contained. The particle diameter can be determined by a dynamic light scattering method. The median diameter of BD and UDD obtained at this stage is 1000 nm or less, preferably 250 nm or less, more preferably 30 to 250 nm.

BD and UDD mainly have a graphite phase at grain boundaries and surfaces.
BD and UDD include (i) amorphous carbon, (ii) hydrocarbon impurities such as hydrocarbons and heteroatom-containing hydrocarbons, and (iii) metals such as iron and oxides and salts thereof as impurities other than graphite. (Metal sulfates, metal carbonates, etc.), carbides, etc., and (iv) non-metallic inorganic substances such as silicon and sulfur, and oxides thereof.
BD and UDD have functional groups and bonds that these impurities mainly composed of graphite have. As functional groups, methyl group, methylene group, methine group, carbonyl group, ketone group, ester group, carboxyl group, ether group, aldehyde group, amino group, amide group, nitro group, nitrate ester group, sulfonic acid group, carbon atom And a hydroxyl group (bonding hydroxyl group) bonded to.
In order to obtain the nanodiamond of the present invention, in a fluid in which oxygen and a processing solvent composed of water and / or alcohol coexist, BD or Since the UDD is processed, the above impurities can be sufficiently decomposed or dissolved, and the nanodiamond can be lightened.

[2] Purification method The purification method of the graphite phase-containing nanodiamond is:
(2-1) Prepare a mixture of graphite phase-containing nanodiamond and a processing solvent comprising water and / or alcohol,
(2-2) In a state where oxygen is present in the nanodiamond-solvent mixture, the graphite phase-containing nanodiamond is subcritically processed or supertreated at a temperature higher than the normal boiling point of the processing solvent and at a pressure higher than 1 atm (gauge pressure). Critical processing,
(2-3) A step of centrifuging the liquid containing the purified nanodiamond obtained to remove the processing solvent.
In addition, after the step (2-3), a step (2-4) of washing the purified nanodiamond subjected to the detreatment solvent and a step (2-5) of centrifuging may be provided.
When the process up to step (2-3) or step (2-5) is performed, the purified nanodiamond obtained in step (2-5) is added to a suspension by adding a dispersion solvent, or dried to collect the purified nanodiamond. A powder may be used. This dispersion solvent may be water, an organic solvent such as alcohol, or a mixture thereof. You may add a dispersing agent to the suspension of refined diamond as needed.

(2-1) Nanodiamond-solvent mixture preparation step The concentration of the graphite phase-containing nanodiamond in the nanodiamond-solvent mixture is preferably 0.05 to 16% by mass, more preferably 0.1 to 12% by mass. 10 mass% is most preferable. When the concentration is in the above-described range, the balance between the two is excellent from the viewpoint of purification and productivity.

  As the processing solvent, water, alcohol or a mixture thereof is used. The alcohol is preferably a lower alcohol having 1 to 3 carbon atoms (hereinafter simply referred to as “lower alcohol”). Specific examples of the lower alcohol include methanol, ethanol, n-propanol, isopropanol, and a mixture thereof.

(2-2) Purification treatment step The nanodiamond-solvent mixture is placed in an autoclave and oxygen is introduced. A catalyst such as boron oxide may be added as necessary. Moreover, when there exists air in an autoclave, it is preferable to substitute with oxygen. The amount of oxygen introduced is preferably 0.1 mol or more, more preferably 0.15 mol or more, and most preferably 0.2 mol or more with respect to 1 g of graphite in the graphite phase-containing nanodiamond. The upper limit of the introduction amount is not particularly limited. The ratio of graphite in the nanodiamond is determined by measuring the specific gravity of the nanodiamond according to, for example, JIS K2249. From this specific gravity, the specific gravity of the diamond is 3.50 g / cm ³ and the specific gravity of the graphite is 2.25 g / cm 3. ³ can be calculated.

The temperature and pressure in the autoclave are adjusted so as to be equal to or higher than the standard boiling point Tb and one atmospheric pressure (gauge pressure) of the processing solvent.
As long as the processing solvent is at least Tb and at least one atmospheric pressure (gauge pressure), the processing solvent may be in a subcritical state or a supercritical state. In this refining process step, the graphite phase is efficiently selectively oxidized at a relatively low temperature and pressure by the action of subcritical or supercritical oxygen, which is known to have high reactivity, and a processing solvent. can do.
Here, the “subcritical state” usually means a state at a temperature equal to or higher than Tb and a pressure equal to or higher than one atmospheric pressure (gauge pressure) and lower than the critical temperature Tc and / or lower than the critical pressure Pc. A state where the temperature is equal to or higher than the critical temperature Tc of the processing solvent 150 ° C. and 30% or higher of the critical pressure of the processing solvent, more preferably the critical temperature Tc of the processing solvent Tc of 100 ° C. At a temperature of 50% or more of the critical pressure of the processing solvent.

  The lower limit of the treatment temperature is preferably (critical temperature of treatment solvent Tc-150 ° C), more preferably (Tc-100 ° C). The upper limit of the treatment temperature is preferably 800 ° C, more preferably 600 ° C. The processing time may be appropriately set depending on the temperature and pressure, but 0.1 to 24 hours is preferable.

Table 1 below shows Tb, Tc and Pc of oxygen, water and lower alcohol.
The Tc of water and lower alcohol is significantly higher than the Tc of oxygen (−118 ° C.), and the Pc of water and lower alcohol is greater than or equal to Pc of oxygen (5.1 MPa).
Therefore, when the processing solvent composed of water and / or lower alcohol is set to Tb or more and one atmospheric pressure (gauge pressure) or more, oxygen remains in a subcritical state or becomes a supercritical state, and when the processing solvent is set to a supercritical state, Becomes a supercritical state.

(2-3) Detreatment solvent process The obtained liquid containing purified nanodiamond is centrifuged to remove the treatment solvent.

(2-4) Washing step The purified nanodiamond that has been subjected to the solvent removal may be washed with water by a decantation method. The washing operation is preferably performed three times or more.

(2-5) Dehydration process It is preferable that the purified nanodiamond washed with water is centrifuged and dehydrated.

The purification process of nanodiamond is
(3-1) A mixture containing a graphite phase-containing nanodiamond, an acidic compound, and a treatment solvent comprising water and / or alcohol is prepared,
(3-2) treating the nanodiamond-acidic compound-solvent mixture at a temperature and pressure above the critical point of the treatment solvent;
(3-3) It can also be realized by a method having a step of removing the processing solvent by centrifuging the liquid containing the purified nanodiamond obtained. In addition, after completion | finish of a process (3-3), it is preferable to provide the process (3-4) which wash | cleans the refined nano diamond which removed the solvent, and the process (3-5) which centrifuges. Between the step (3-3) and the step (3-4), if necessary, a step (3-6) of neutralizing the desolvated purified nanodiamond with a basic solution, and a step of treating with a weak acid (3-7) may be provided. The purified nanodiamond obtained in the step (3-3) or (3-5) may be made into a suspension or a fine powder in the same manner as described above.

(3-1) Process of preparing nanodiamond-acidic compound-solvent mixture Treatment of graphite phase-containing nanodiamond Add acidic compound or its solution to the solvent dispersion, or dry graphite phase-containing nanodiamond with acidic compound and treatment A nanodiamond-acidic compound-solvent mixture is prepared by adding a solvent.

  Examples of acidic compounds include inorganic acids such as nitric acid, sulfuric acid, hydrochloric acid, phosphoric acid, boric acid, hydrofluoric acid, and hydrobromic acid, and organic acids such as formic acid, acetic acid, methanesulfonic acid, benzenesulfonic acid, and p-toluenesulfonic acid. Although an acid is mentioned, an inorganic acid is preferable and nitric acid is more preferable.

  If necessary, an oxidizing compound may be further added. Examples of oxidizing compounds include hydrogen peroxide, sodium percarbonate, potassium percarbonate, sodium perborate, potassium perborate, sodium hypochlorite, potassium hypochlorite, sodium chlorite, potassium chlorite, Lithium chlorate, sodium chlorate, potassium chlorate, lithium perchlorate, sodium perchlorate, potassium perchlorate, sodium permanganate, potassium permanganate, sodium manganate, potassium manganate, sodium persulfate, persulfate Examples include potassium sulfate, potassium dichromate, and potassium chromate, and hydrogen peroxide is preferable. A preferred combination of an acidic compound and an oxidizing compound is a combination of nitric acid and hydrogen peroxide. Note that the supercritical treatment described later can be performed without using an acidic compound, but in this case, an oxidizing compound, particularly hydrogen peroxide, can be used alone.

  The concentration of the nanodiamond containing graphite phase in the nanodiamond-acidic compound-solvent mixture may be the same as in the first method. In order to sufficiently purify, the concentration of the compound in the nanodiamond-acidic compound-solvent mixture is preferably 0.01 to 10 mol / L, and more preferably 0.1 to 5 mol / L.

(3-2) Supercritical processing step The nanodiamond-acidic compound-solvent mixture is processed at a temperature and pressure above the critical point of the processing solvent. The critical temperature Tc and critical pressure Pc of water and lower alcohol are as described in the above table. The temperature is preferably from the critical temperature of the processing solvent to 600 ° C. The upper limit of the temperature is more preferably 550 ° C. The pressure is preferably a critical pressure of the processing solvent to 100 MPa. The upper limit of the pressure is more preferably 70 MPa, and most preferably 50 MPa. The treatment time may be appropriately set depending on the temperature and pressure, but is preferably 1 to 24 hours.

(3-3) Solvent removal step, (3-4) Water washing step, and (3-5) Dehydration step (3-3) to (3-5) may be the same as the above-described method.

(3-6) Neutralization Step The purified nanodiamond removed from the solvent in the step (3-3) may be neutralized with a basic solution. As the basic solution, an aqueous sodium hydroxide solution and an aqueous potassium hydroxide solution are preferred. The concentration of the basic solution is preferably 0.01 to 0.5 mol / L. It is preferable to add a basic solution to the desolvated purified nanodiamond and perform ultrasonic treatment. After neutralization, the mixture is centrifuged to remove the basic solution.

(3-7) Weak Acid Treatment Step It is preferable to wash the purified nanodiamond neutralized in step (3-6) with a weak acid solution. With the weak acid solution, metal ions such as sodium remaining after the neutralization treatment can be removed. Examples of the weak acid solution include 0.01 to 0.5 mol / L hydrochloric acid. It is preferable to add a weak acid solution to the neutralized purified nanodiamond and perform ultrasonic treatment. After washing, centrifuge to remove the weak acid solution.

[Process (B)]
In the treatment (B), the liquid containing the nanodiamond prepared in the treatment (A) is re-dispersed in an appropriate medium as it is or after being centrifuged, and is atomized. Further, if necessary, the treatment solvent is removed by centrifugation.

This atomization treatment can be performed, for example, on a dispersion in which nanodiamond prepared in the treatment (A) is dispersed in water, alcohols, or other appropriate organic solvents. Further, the dispersion is refined by combining a wet pulverization method represented by a technique using a bead mill and / or a high energy ultrasonic treatment method.
Here, as an example of the wet dispersion method corresponding to the wet pulverization method, the slurry of the object to be pulverized is jet-injected, the jet stream is divided into two, and when the merging is performed again, the head collides, When jet slurry is pulverized by energy, or when the slurry of the material to be pulverized is rotated at a high speed, it is pressed against the inner wall of the rotating tank using a special stirring blade to form a thin film, and pulverization is realized by the shear stress of the stirring blade. There are thin film methods.

  More specifically, a fine pulverization or dispersion apparatus (for example, a wet pulverization / dispersion technique using zirconia beads as a pulverization medium such as MINI CER of Ashizawa Finetech Co., Ltd. or Starmill (trademark) Nano Getter DMS65) It can be carried out over several minutes to several hours.

  The nanodiamond of the present invention obtained by the above method has a feature that it has a particle size of 2 nm to 100 nm and does not reaggregate.

Further, the atomized nanodiamond may be washed with water, dehydrated, and redispersed.
In the step of washing with water, the atomized nanodiamond is washed with water, for example, by a decantation method. The washing operation is preferably performed three times or more.
In the step of dehydrating, for example, the nanodiamond washed with water is centrifuged and further dehydrated.
In the step of redispersing, the nanodiamonds that have been washed and dehydrated are redispersed in an appropriate dispersion medium in accordance with the actual use conditions.

  From another aspect, the present invention provides a polymerizable composition comprising the nanodiamond described above and a compound containing a sulfur atom and / or a metal atom.

  Examples of the compound containing a metal atom that can be used in such a polymerizable composition include those described in, for example, Republished 2005-095490, International Publication No. 2009/087717, and the like. Examples thereof include compounds having one or two or more thietane groups in the molecule and containing a metal atom, and nonmetal thietanes containing one or more thietanyl groups in the molecule.

A compound having one or more thietane groups in the molecule and containing a metal atom will be described.
The metal atom used in this compound is preferably Sn atom, Si atom, Zr atom, Ge atom, Ti atom, Zn atom, Al atom, Fe atom, Cu atom, Pt atom, Pb atom, Au atom or Ag atom More preferably, they are Sn atom, Si atom, Zr atom, Ti atom, Ge atom, Al atom, Pb atom or Zn atom, and more preferably Sn atom, Si atom, Zr atom, Ti atom and Ge atom.

  The thietane group is preferably a thietane group represented by the general formula (1) or (2).

[Wherein, A1 to A10 each independently represents a hydrogen atom or a monovalent inorganic or organic residue]

  Such monovalent inorganic or organic residues include halogen atoms, hydroxyl groups, thiol groups, substituted or unsubstituted alkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted aralkyl groups, substituted or unsubstituted alkoxy groups. A group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group;

  Further, the bond between the thietane group represented by the general formula (1) or (2) and the metal atom is not particularly limited. That is, it may be directly bonded to a metal atom or may be bonded via an appropriate linking group. Examples of the linking group include, but are not limited to, a chain or cyclic aliphatic group, an aromatic group or an aromatic-aliphatic group, and a group represented by the general formula (3).

[Wherein, X ₁ and X ₂ each independently represent a sulfur atom or an oxygen atom, R ₁ represents a divalent organic group, and m represents 0 or an integer of 1 or more.]

  Such a linking group may contain a hetero atom other than a carbon atom and a hydrogen atom in the group. Examples of such a hetero atom include an oxygen atom or a sulfur atom, but a sulfur atom is preferable in consideration of a desired effect of the present invention.

Next, the nonmetallic thietane compound will be described.
Non-metallic thietane compounds contain one or more thietanyl groups in the molecule. The nonmetallic thietane compound may be any compound having any structure as long as it is compatible with the additive of the present invention, but is preferably a compound containing two or more thietanyl groups in total.

Specifically, as the nonmetallic thietane compound, a sulfide-type thietane compound such as bisthietanyl sulfide, bis (3-thietanylthio) methane, 3-(((3′-thietanylthio) methylthio) methylthio) thietane:
Examples thereof include polysulfide-based thietane compounds such as bis (3-thietanyl) disulfide, bis (3-thietanyl) trisulfide, bis (3-thietanyl) tetrasulfide, and bis (3-thietanyl) pentasulfide.

  Here, the “polymerizable composition” is a polymerizable composition containing a compound containing a sulfur atom and / or a metal atom and the above-described atomized nanodiamond.

  The polymerization catalyst used as needed for this polymerizable composition is not particularly limited, and for example, a known polymerization catalyst described in JP-A No. 2003-327583 and the like can be used. Examples of such polymerization catalysts include amine compounds, phosphine compounds, organic acids and derivatives thereof (salts, esters or acid anhydrides), inorganic acids, quaternary ammonium salt compounds, quaternary phosphonium salt compounds, tertiary sulfonium salt compounds. An onium salt compound such as a secondary iodonium salt, a Lewis acid compound, a radical polymerization catalyst, a cationic polymerization catalyst, or the like is used.

  Further, when producing the polymerizable composition, an internal mold release agent, a light stabilizer, an ultraviolet absorber, an antioxidant, a color pigment (for example, cyanine) may be used as long as the effect of the present invention is not impaired. It is possible to add various known additives such as green, cyanine blue, etc.), dyes, flow regulators, fillers and the like.

  Furthermore, from another aspect, the present invention provides a polymerizable composition comprising the following components (b-1) to (b-3).

(B-1) One or more compounds selected from polyisocyanate compounds, polyisothiocyanate compounds, and isothiocyanate compounds having an isocyanate group:
(B-2) One or more compounds selected from polyol compounds, polythiol compounds, and alcohol compounds having a mercapto group: and (b-3) the nanodiamond described above.

  As each of the compounds (b-1) and (b-2) that can be used in such a polymerizable composition, for example, those described in Republished 2008-018168 can be used. Are compounds shown below, respectively.

  Examples of the polyisocyanate compound include hexamethylene diisocyanate, isophorone diisocyanate, bis (isocyanatemethyl) cyclohexane, dicyclohexylmethane diisocyanate, 2,5-bis (isocyanatemethyl) bicyclo- [2.2.1] -heptane, 2,6 -Bis (isocyanatomethyl) bicyclo- [2.2.1] -heptane, m-xylylene diisocyanate, 2,5-bis (isocyanatomethyl) -1,4-dithiane.

  Examples of the polyisothiocyanate compound include those obtained by changing the isocyanate group of the polyisocyanate compound exemplified above to an isothiocyanate group.

  Examples of the isothiocyanate compound having an isocyanate group include those obtained by changing a part of the isocyanate group of the polyisocyanate compound exemplified above to an isothiocyanate group.

  These polyisocyanate compounds, polyisothiocyanate compounds, and isothiocyanate compounds having an isocyanate group can be used alone or in combination of two or more.

  Examples of the polyol compound include ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,4- Pentanediol, 1,3-pentanediol, 1,6-hexanediol, 1,5-hexanediol, 1,4-hexanediol, 1,3-hexanediol, 1,2-cyclohexanediol, 1,3-cyclohexane Diol, 1,4-cyclohexanediol, 1,7-heptanediol, 1,8-octanediol, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, xylitol, 1,2-dihydroxybenzene, 1,3-dihydro Shibenzen, 1,4-dihydroxybenzene, m- xylylene glycol, p- xylylene glycol, o- xylylene glycol.

  Examples of the polythiol compound include pentaerythritol tetrakis (2-mercaptoacetate), pentaerythritol tetrakis (3-mercaptopropionate), bis (mercaptoethyl) sulfide, 4-mercaptomethyl-1,8-dimercapto-3. , 6-dithiaoctane, 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-tri Thiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 2,5-dimercaptomethyl-1,4-dithiane, 1,1,3,3-tetrakis (Mercaptomethylthio) propane, 4,6-bis (mercaptomethylthio) -1,3-dithiane, 2- (2,2- Scan (mercaptomethylthio) ethyl) -1,3-dithietane and the like.

Examples of the alcohol compound having a mercapto group include 2-mercaptoethanol, 3-mercapto-1,2-propanediol, glycerin bis (mercaptoacetate), 4-mercaptophenol, 2,3-dimercapto-1-propanol, Examples include pentaerythritol tris (3-mercaptopropionate) and pentaerythritol tris (thioglycolate).
These polyol compounds, polythiol compounds, and alcohol compounds having a mercapto group can be used alone or in combination of two or more.

  Here, the “polymerizable composition” means at least one selected from the compound (b-1), at least one selected from the compound (b-2), and the above-described atomized nanodiamond (b-3). ) Containing a polymerizable composition.

  Furthermore, a resin modifier such as an olefin compound including a hydroxy compound, an epoxy compound, an episulfide compound, an organic acid and its anhydride, a (meth) acrylate compound, and the like may be added for the purpose of modifying the resin. Here, the resin modifier is a compound that adjusts or improves the physical properties such as refractive index, Abbe number, heat resistance, specific gravity and mechanical strength such as impact resistance of the thiourethane resin.

  In addition, if necessary, in the same manner as in known molding methods, catalysts such as dibutyltin dichloride, UV absorbers such as benzotriazole, internal mold release agents such as acidic phosphates, light stabilizers, antioxidants Substances such as a reaction initiator such as a radical reaction initiator, a chain extender, a cross-linking agent, an anti-coloring agent, an oil-soluble dye, and a filler may be added.

  Furthermore, from another aspect, the present invention provides a polymerizable composition comprising the following components (c-1) and (c-2).

(C-1) Compound containing episulfide group: and (c-2) Nanodiamond described above.

  As the compound containing an episulfide group that can be used in such a polymerizable composition, for example, those described in JP-A-2003-335859 can be used, and specific examples include the compounds shown below. .

(Wherein R _1a represents a hydrocarbon group having 1 to 10 carbon atoms, R _2a , R _3a and R _4a represent a hydrocarbon group having 1 to 10 carbon atoms or a hydrogen atom, respectively). Contains one or more compounds.

In the formula (4), R _1a represents a divalent hydrocarbon group having 1 to 10 carbon atoms, specifically, a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms, phenylene, alkyl-substituted phenylene And an arylene group having 6 to 10 carbon atoms, such as naphthalene, or an aralkylene group having 7 to 10 carbon atoms composed of a combination of alkylene and arylene, an alkylene group having 1 to 10 carbon atoms is preferable. More preferred is methylene or ethylene. More preferred is methylene. R _2a , R _3a and R _4a each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, and examples of the monovalent hydrocarbon group having 1 to 10 carbon atoms include straight chain, branched or Although a cyclic | annular C1-C10 alkyl group, a C6-C10 aryl group, and a C7-C10 aralkyl group are mentioned, a hydrogen atom or a C1-C10 alkylene group is preferable. A hydrogen atom or a methyl group is more preferable. A hydrogen atom is more preferable.

  Here, the “polymerizable composition” means a compound (c-1) containing an episulfide group having at least one structure represented by the formula (4) and the above-described atomized nanodiamond (c-2) The polymerizable composition includes a curing catalyst that catalyzes a polymerization reaction, polysulfide oligomers such as dimers, trimers, and tetramers of exemplary compounds, polymerization inhibitors, and the like. Inorganic acids and organic acids added as organic solvents, organic compounds such as solvents and other by-products, and inorganic compounds may also be included within a range not causing problems.

  As the curing catalyst that can be used here, tertiary amines, phosphines, quaternary ammonium salts, quaternary phosphonium salts, Lewis acids, radical polymerization catalysts, cationic polymerization catalysts and the like are usually used.

  Such a polymerizable composition can be applied not only to a high refractive index resin but also to a medium refractive index resin, mainly for adjusting various physical properties such as impact resistance and specific gravity of the obtained resin, A resin modifier can be added for the purpose of improving the resin, such as to adjust the viscosity and other handling properties.

  Examples of the resin modifier include thioepoxy compounds other than the thioepoxy compound contained in the polymerizable composition according to the present invention, thiol compounds, iso (thio) cyanates, mercapto organic acids, organic acids and anhydrides, amino acids and mercapto Examples include olefins including amines, amines, (meth) acrylates, and the like.

  In the case of resin molding, a chain extender, a crosslinking agent, a light stabilizer, an ultraviolet absorber, an antioxidant, an anti-coloring agent, a dye, a filler, as in the case of a known molding method, depending on the purpose. Various substances such as an external or internal mold release agent and an adhesion improver may be added.

  From a further viewpoint, the present invention provides a resin obtained by polymerizing the polymerizable composition, and an optical component such as a lens made of the resin.

  A typical polymerization method for obtaining the resin (for example, plastic lens) of the present invention includes cast polymerization. That is, the above-described polymerizable composition containing a curing catalyst is injected between the molding molds held by a gasket or a tape, if necessary. At this time, there is no problem even if processing such as defoaming is performed as necessary.

Then, it can be cured by heating in a heatable apparatus such as an oven or water, and the resin can be taken out.
In addition, an optical component other than a spectacle lens can be obtained by appropriately selecting a casting polymerization type.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1
(Adjustment of atomized nano diamond)
・ Process (A)
2.0% by mass UDD (specific gravity measured in accordance with JIS K2249 is 3.38 g / cm ^{3. From} this specific gravity, the specific gravity of diamond is 3.50 g / cm ³ and the specific gravity of graphite is 2.25 g. The composition calculated as / cm ³ was 90% by volume of diamond and 10% by volume of graphite. From the particle size distribution of UDD measured by the dynamic light scattering method, manufactured by Vision Development Co., Ltd. 30 mL of particles confirmed to contain no particles exceeding 000 nm and whose median diameter was determined to be 25 nm were placed in an autoclave (capacity 50 mL, manufactured by SUS316) and sealed with a lid having an oxygen inlet tube, a temperature sensor, and a pressure regulating valve. . The air in the autoclave was replaced with oxygen, oxygen was introduced at room temperature so that the pressure in the autoclave was 1.0 MPa (gauge pressure), the autoclave was installed in the furnace, and the average heating rate was 6.5 ° C. / Min. After reaching 400 ° C., it was treated at a temperature of 400 ± 5 ° C. and a pressure of 24.8 ± 1 MPa for 1 hour, cooled to room temperature, then reduced to atmospheric pressure, and a liquid containing purified nanodiamond was recovered. This liquid was separated into a supernatant and a precipitate of purified nanodiamonds showing a light gray color.

The purified nanodiamond-containing liquid was centrifuged, the supernatant liquid was removed, the dehydrated purified nanodiamond was washed with water three times by a decantation method, quickly separated, and the dehydrated purified nanodiamond was heated and dried at 120 ° C. The removal rate calculated from the difference in dry mass between UDD and purified nanodiamond was 5.9% by mass, with UDD being 100% by mass. The specific gravity of the purified nanodiamond was 3.49 g / cm ³ . The composition calculated from this specific gravity was 99% by volume of diamond and 1% by volume of graphite.

・ Process (B)
Triethylene glycol dispersion containing purified nanodiamond obtained by treatment (A) at 5.0% by mass (made by Vision Development Co., Ltd .; the average particle size at the time of production was 200 nm or less, but was coagulated and precipitated. ) Was subjected to wet pulverization with zirconia beads (bead diameter: 0.1 mm) [apparatus condition: MINI CER Ashizawa Finetech Co .; peripheral speed: 10 m / Sec; temperature: 40-50 ° C.]. When the change in particle size over time (average particle size) was confirmed by a particle size distribution meter (dynamic light scattering UPA), it was 68 nm after 15 minutes and 62 nm after 30 minutes, but 56 nm after 1 hour and 1.5 hours later It was confirmed that the particles could be gradually atomized to 40 nm after 2 hours at 40 nm. The dispersion (average particle diameter: 40 nm) collected after the treatment for 2 hours was stably present without causing aggregation or sedimentation even after 5 days.
In addition, the average particle diameter here means a median diameter.

(Example 2)
(Application of atomized nanodiamond to optical resin)
A triethylene glycol dispersion (average particle size: 40 nm) (0.8 g) of 5.0% by mass nanodiamond treated with zirconia beads in Example 1 at 20 ° C., dibutyltin dichloride (10 mg), internal mold release agent (Product name: Zelec UN, manufactured by STEPAN) 30 mg and 2,5-bis (isocyanatomethyl) -bicyclo [2.2.1] heptane and 2,6-bis (isocyanatomethyl) -bicyclo [2.2. 1] It was mixed with a mixture of heptanes (5.4 g) to obtain a uniform solution. Further, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane (3.8 g) was added and mixed. After defoaming for 10 minutes under reduced pressure, it was poured into a mold consisting of a glass mold and a tape. This mold was put into a polymerization oven and polymerized by gradually raising the temperature from 25 ° C. to 120 ° C. over 24 hours. After completion of the polymerization, the mold was removed from the oven and released to obtain a resin. When the refractive index of the resin was measured with a Purfrich refractometer, the refractive index (ne) was 1.605.

(Comparative example)
A cured resin was obtained in the same manner as in Example 2, except that the triethylene glycol dispersion (0.8 g) of 5.0% by mass nanodiamond in Example 2 was replaced with triethylene glycol (0.8 g). When the refractive index of the resin was measured with a Purfrich refractometer, the refractive index (ne) was 1.603.

(result)
The resin of Example 2 had a higher refractive index than the resin of the comparative example, and the hue and transparency were the same.

Claims (8)

A nanodiamond containing a graphite phase and having a particle diameter of 95% or more determined by a dynamic light scattering method of 1,000 nm or less in a fluid in which (A) a treatment solvent comprising oxygen and water and / or alcohol coexists, Subcritical or supercritical treatment of the nanodiamond at a temperature above the normal boiling point of the treatment solvent and a pressure above 1 atm (gauge pressure), and
(B) Nanodiamond obtained by atomization.   The lightened nanodiamond according to claim 1, wherein the average particle diameter is 2 to 100 nm.   A polymerizable composition comprising the nanodiamond according to claim 1 and a compound containing a sulfur atom and / or a metal atom. (1) One or more compounds selected from a polyisocyanate compound, a polyisothiocyanate compound, an isothiocyanate compound having an isocyanate group, and (2) a polyol compound, a polythiol compound, and an alcohol compound having a mercapto group. A polymerizable composition comprising a seed or two or more compounds and (3) the nanodiamond according to claim 1. (1) A polymerizable composition comprising an episulfide group-containing compound and (2) the nanodiamond according to any one of claims 1 to 2.   A resin obtained by polymerizing the polymerizable composition according to any one of claims 3 to 5.   An optical component made of the resin according to claim 6.   A lens made of the resin according to claim 6.

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