KR20220159246A - Dispersant and composition - Google Patents

Abstract

The present disclosure relates to a dispersant including a specific compound having a fluorene-based skeleton, and a composition using the same. The dispersant is capable of uniformly distributing high refractive nanoparticles in an optical polymer.

Description

Dispersant and composition {DISPERSANT AND COMPOSITION}

The present disclosure relates to a dispersant and a composition using the dispersant, for example, they can be used in an optical lens of a camera module.

The main optical properties that a camera lens material should have can be largely classified into refractive index, birefringence, Abbe number, transmittance, etc., and it is important to design to be advantageous for each property. Among them, the refractive index is the most important item. As the refractive index increases, the lens can be made thinner and the resolving power can be increased, so it is a characteristic that is central to the development of lens materials.

In order to manufacture a camera lens having such a high refractive index, an inorganic material such as glass or a high refractive index polymer is used. Polymer materials are lightweight, do not break easily, and are inexpensive in terms of price, so they have many advantages over inorganic materials. In addition, since the range of refractive index can be adjusted according to the chemical structure of the polymer, it is used as an optical material according to the purpose.

However, since there is a limit to increasing the refractive index by changing the chemical structure of the polymer, recently, research has been conducted in the direction of increasing the refractive index by incorporating high refractive nanoparticles into a polymer matrix.

One of the various objects of the present disclosure is to provide a dispersant capable of uniformly distributing high refractive nanoparticles in an optical polymer and a composition using the same, for example, a dispersant and composition for an optical lens of a camera module.

One of the various solutions proposed through the present disclosure is to use a dispersant containing a specific compound having a fluorene-based skeleton.

For example, the dispersant according to one example may include a compound represented by [Formula 1].

[Formula 1]

X ¹ and X ² are each an aromatic ring, R ¹ , R ² , R ³ and R ⁴ are each a substituent, a, b, c and d are each an integer from 0 to 4, R ⁵ and R ⁶ are each An aliphatic chain, n and m are each an integer of 2 to 20, Y ¹ and Y ² are each a bonding group represented by the following [Formula 2], Z ¹ and Z ² are each of the following [Formula 3] or [Formula 4] It is a terminal group represented by ],

[Formula 2]

R ⁷ is an O, N or S atom, R ⁸ is an aliphatic chain, - ^* means a linking site with Z ¹ or Z ² ,

[Formula 3]

R ⁹ is an aliphatic chain;

[Formula 4]

R ¹⁰ is an aliphatic chain.

For example, the composition according to one example may include zirconia nanoparticles surface-treated with a dispersant containing a compound represented by Formula 1, and a solvent.

As one of the various effects of the present disclosure, a dispersant capable of uniformly distributing high refractive nanoparticles in an optical polymer and a composition using the same, for example, a dispersant and composition for an optical lens of a camera module may be provided.

1 schematically shows the treatment of the surface of zirconia nanoparticles using a dispersant according to an example.
2 schematically shows IR (Infrared Spectroscopy) spectra according to the treatment amount of the dispersant on the surface of the surface-treated zirconia nanoparticles.
Figure 3 schematically shows the transparency of the composite of zirconia nanoparticles and high refractive index polymer when the surface is not treated with a dispersant, and the transparency of the composite material of zirconia nanoparticles and high refractive index polymer when the surface is treated with a dispersant.

Hereinafter, the present disclosure will be described with reference to the accompanying drawings. The shapes and sizes of elements in the drawings may be exaggerated or reduced for clearer description.

dispersant

As described above, a high refractive index polymer having various advantages is used to manufacture a camera lens with a high refractive index, but there is a limit to increasing the refractive index by changing the chemical structure of the polymer. It is desired to increase the refractive index by incorporating into.

Here, since nanoparticles such as zirconium oxide and titanium oxide must be smaller than the minimum wavelength of light to reduce light scattering, they must be prepared with a uniform diameter of 15 nm or less. In addition, in order to prevent the intensity (Intensity) of transmitted light from being reduced due to Rayleigh scattering and to increase the refractive index of the composite material efficiently, it must be evenly dispersed in the polymer matrix.

Meanwhile, a composite material used for optical purposes may be prepared by incorporating nanoparticles into a thermosetting polymer or a thermoplastic polymer. The nanoparticle and thermosetting polymer composite may be prepared by mixing an acryl-based liquid monomer and nanoparticles and then proceeding with polymerization. In this case, the surface of the nanoparticles can react with acryl and are modified into molecules having a structure similar to acryl, so that the mixing of the two different materials can be increased.

In addition, in order to incorporate nanoparticles using a thermoplastic polymer, a method of mixing the polymer and nanoparticles in a molten state by applying heat and a method of dissolving both the polymer and nanoparticles with a solvent and then removing the solvent can be used. In addition, it may be necessary to modify the surface of nanoparticles with a dispersant to increase the affinity of the interface between the two different materials and evenly disperse the nanoparticles in the solvent.

In particular, cyclic olefins, polyesters, polycarbonates, etc. may be used as thermoplastic polymers for optical use, and among them, polyesters and polycarbonates containing a large number of aromatic rings in a high volume ratio are preferably used as high refractive thermoplastic polymers. It can be. Among aromatic rings, fluorene does not cause birefringence due to its structural characteristics, and is thus advantageous for use as an optical lens.

Therefore, in order to increase the affinity of the interface between a thermoplastic polymer having a fluorene group and nanoparticles, for example, zirconia nanoparticles having a hydrophilic surface, it may be required to design a chemical structure of a dispersant suitable for this structure.

From this point of view, the dispersant according to an example may include a specific compound having a fluorene-based skeleton, for example, a compound represented by the following [Formula 1].

[Formula 1]

Here, X ¹ and X ² may each be an aromatic ring. As an aromatic ring, a benzene ring, a naphthalene ring, a biphenyl ring etc. are mentioned, for example. Preferably, it may be a benzene ring, but is not limited thereto. Aromatic rings may have substituents. Examples of the substituent include a halogen group, a cyano group, a nitro group, a hydroxyl group, a C ₁ ~ C ₁₀ alkyl group, a C ₁ ~ C ₁₀ alkoxy group, a C ₂ ~ C ₁₀ alkene group, a C ₂ ~ C ₁₀ alkyne group, C ₄ -C ₁₀ alkene groups; and the like. An alkyl group, an alkene group, an alkyne group, an alkenayne group, and the like may each be in the form of a straight chain or branched chain.

For example, the C ₁ ~C ₁₀ alkyl group is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl -Butyl group, pentyl group, isopentyl group, neopentyl group, tert-pentyl group, hexyl group, 1-methylpentyl group, 2-methylpentyl group, 4-methyl-2-pentyl group, 3,3-dimethylbutyl group, 2-ethylbutyl group, heptyl group, 1-methylhexyl group, octyl group, nonyl group, decyl group and the like, but is not limited thereto.

For example, the alkoxy group of C ₁ to C ₁₀ is methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, tert-butoxy, sec-butoxy, pentyloxy, neopentyloxy, isopentyl It may be oxy, hexyloxy, 3,3-dimethylbutyloxy, 2-ethylbutyloxy, octyloxy, nonyloxy, decyloxy, etc., but is not limited thereto.

For example, the C ₂ ~C ₁₀ alkene group includes a vinyl group, 1-propenyl group, 1-butenyl group, etc., and the C ₂ ~C ₁₀ alkyne group includes an ethynyl group, a 1-propynyl group, and a 1-butynyl group. and the like, and the C ₄ ~C ₁₀ alkenaine group may include, but is not limited to, a pent-1-en-4-yne group and a pent-3-en-1-yne group.

In addition, R ¹ , R ² , R ³ and R ⁴ may each be a substituent. Examples of the substituent include, as described above, a halogen group, a cyano group, a nitro group, a hydroxyl group, a C ₁ ~ C ₁₀ alkyl group, a C ₁ ~ C ₁₀ alkoxy group, a C ₂ ~ C ₁₀ alkene group, a C ₂ ~ C ₁₀ an alkyne group, a C ₄ to C ₁₀ alkene group, and the like. An alkyl group, an alkene group, an alkyne group, an alkenayne group, and the like may each be in the form of a straight chain or branched chain. Specific examples of an alkyl group, an alkene group, an alkyne group, and an alkene group are as described above, but are not limited thereto.

In addition, a, b, c, and d may each be an integer of 0 to 4. Preferably, a, b, c, d, etc. may be 0, and thus the fluorene backbone and the aromatic ring may not have substituents, but is not limited thereto.

In addition, R ⁵ and R ⁶ may each be an aliphatic chain. The aliphatic chain may be a saturated hydrocarbon chain, an unsaturated hydrocarbon chain, or the like. The saturated hydrocarbon chain, unsaturated hydrocarbon chain, etc. may each be straight chain or branched. Preferably, R ⁵ and R ⁶ are each a C ₂ -C ₆ saturated hydrocarbon chain, for example -(CH ₂ -CH ₂ )-, -(CH ₂ -CH ₂ -CH ₂ )-, -( CH ₂ -CH ₂ -CH ₂ -CH ₂ )-, -(CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ )-, -(CH ₂ -CH ₂ -CH ₂ -CH ₂ -CH ₂ - CH ₂ )- and the like, more preferably a C ₂ to C ₄ saturated hydrocarbon chain, for example, -(CH ₂ -CH ₂ )-, -(CH ₂ -CH ₂ -CH ₂ )-, - (CH ₂ -CH ₂ -CH ₂ -CH ₂ )-, etc., but is not limited thereto.

In addition, n and m may each be an integer of 2 to 20. More preferably, n and m may each be an integer of 5 to 10, but is not limited thereto. Depending on the number of n and m, the chain length of -OR ⁵ - and -OR ⁵ - can be controlled, and as a result, the molecular weight of the compound can be controlled. Through this, it is possible to control the interfacial interaction between the zirconia nanoparticles and the polymer. For example, as the chain length of -OR ⁵ - and -OR ⁵ - decreases, a friendly interaction may occur.

In addition, Y ¹ and Y ² may each be a bonding group represented by the following [Formula 2].

[Formula 2]

Here, R ⁷ may be an O, N or S atom, preferably an O atom, but is not limited thereto. In addition, R ⁸ may be an aliphatic chain, preferably, R ⁸ may be a C ₂ ~ C ₆ saturated hydrocarbon chain, more preferably a C ₂ ~ C ₄ saturated hydrocarbon chain, but is not limited thereto. . Specific examples of the C ₂ ~ C ₆ saturated hydrocarbon chain, C ₂ ~ C ₄ saturated hydrocarbon chain, etc. may be as described above, but are not limited thereto. On the other hand, - ^* may mean a linking site with Z ¹ or Z ² . For example, Y ¹ and Y ² may be connected to Z ¹ and Z ² respectively at -* and vice versa to R ⁵ and R ⁶ respectively.

In addition, Z ¹ and Z ² may each be a terminal group represented by [Formula 3] or [Formula 4].

[Formula 3]

Here, R ⁹ may be an aliphatic chain, preferably, a C ₂ ~ C ₆ saturated hydrocarbon chain, more preferably a C ₂ ~ C ₄ saturated hydrocarbon chain, but is not limited thereto. Specific examples of the C ₂ ~ C ₆ saturated hydrocarbon chain, C ₂ ~ C ₄ saturated hydrocarbon chain, etc. may be as described above, but are not limited thereto.

[Formula 4]

Here, R ¹⁰ may be an aliphatic chain, preferably, a C ₂ ~ C ₆ saturated hydrocarbon chain, more preferably a C ₂ ~ C ₄ saturated hydrocarbon chain, but is not limited thereto. Specific examples of the C ₂ ~ C ₆ saturated hydrocarbon chain, C ₂ ~ C ₄ saturated hydrocarbon chain, etc. may be as described above, but are not limited thereto.

As a non-limiting example, the compound represented by [Formula 1] may include a compound represented by [Formula 5] below. The compound represented by the following [Formula 5] may be prepared through the following [Reaction Scheme 1], but is not limited thereto.

[Formula 5]

Here, n and m may each be an integer of 2 to 20. More preferably, n and m may each be an integer of 5 to 10, but is not limited thereto.

[Scheme 1]

As another non-limiting example, the compound represented by [Formula 1] may include a compound represented by [Formula 6] below. The compound represented by the following [Formula 6] may be prepared through the following [Reaction Scheme 2], but is not limited thereto.

[Formula 6]

Here, n and m may each be an integer of 2 to 20. More preferably, n and m may each be an integer of 5 to 10, but is not limited thereto.

[Scheme 2]

composition

A composition according to an example may include zirconia nanoparticles surface-treated with a dispersant, and a solvent. In this case, the dispersant may be the dispersant according to the above-described example. The composition according to an example may be prepared by treating the surface of the zirconia nanosol with a dispersant, then precipitating the zirconia nanoparticles, discarding the supernatant using centrifugation to obtain the nanoparticles that have settled, and then dispersing them in a solvent. . The dispersant may be adsorbed on the surface of the zirconia nanoparticles, which may be confirmed using optical analysis, such as PM-IRRAS, but is not limited thereto.

On the other hand, the solvent may be tetrahydrofuran, methylene chloride, chloroform, etc., but is not limited thereto. This type of solvent can increase the ease of the composite manufacturing process. For example, tetrahydrofuran, methylene chloride, chloroform, etc. have a boiling point of about 66 ° C, 40 ° C, 61 ° C, and a boiling point of 100 ° C or less, which will be described later. Since it can dissolve the polymer, it can be easily used. Their polarity may be in the order of chloroform, tetrahydrofuran, and methylene chloride, and the higher the polarity, the higher the transparency of the composite material described later. For example, as the composite material described below is prepared using a highly polar solvent, phase separation between the zirconia nanoparticles surface-treated with a dispersant and the polymer described later can be more effectively suppressed.

On the other hand, surface treatment using a dispersant, as shown in [Fig. 1] below, can be performed by adding zirconia nano sol and a dispersant solution to a reaction solvent such as tetrahydrofuran or chloroform, followed by reacting while refluxing. At this time, even if the same dispersant is used, the degree of dispersion in the solvent and the interaction with the polymer described later can be controlled depending on how much the dispersant is fixed on the surface of the zirconia nanoparticles. For example, the polarity of the surface of the zirconia nanoparticles can be controlled by adjusting the amount of the synthesized dispersant, which can affect the degree of dispersion according to the solvent. This may also affect interactions with polymers, which will be described later.

composite

A composite material according to an example may include zirconia nanoparticles surface-treated with a polymer and a dispersant. In this case, the dispersant may be the dispersant according to the above-described example. A composite material according to an example may be prepared by combining a polymer and zirconia nanoparticles surface-treated with a dispersant. For example, it may be prepared by applying the composition according to the example described above to a polymer and then drying it. Alternatively, it may be prepared by adding a polymer to the composition according to the above example and drying it. The polymer and the zirconia nanoparticles surface-treated with the dispersant may be in a state of bonding with each other.

Meanwhile, a polymer may be used as a material for an optical lens for a camera module, and thus may be a polymer having high refractive index. For example, it may be a thermoplastic polymer having a fluorene group. More specifically, it may be polyester having a fluorene group, polycarbonate having a fluorene group, and the like, but is not limited thereto. Since zirconia nanoparticles exhibit relatively hydrophilicity, they can be more easily bonded to such thermoplastic polymers, such as polyester and polycarbonate, through hydrogen bonds.

Meanwhile, in materials where transparency is important, such as an optical lens, a dispersant having a structure similar to the main chain of a polymer must be synthesized and treated on the surface of nanoparticles to be evenly dispersed in a desired solvent as well as in a polymer matrix. If not dispersed, a phase separation phenomenon occurs in which the polymer chain tries to stay with the polymer chain and the nanoparticles with each other, and the agglomerated nanoparticles can impede the transparency of the composite material. It is important to design a dispersant that can be dispersed in all of the matrix. From this point of view, the composite material according to the example can be easily used as an optical lens for a camera module.

However, the content of the present disclosure is not limited to a tubular lens for a camera module, and can be applied to other optical functional materials, etc., of course.

Experimental example

(Synthesis Example 1)

First, 1 equivalent of a fluorene-based compound (starting material of Scheme 1, molecular weight 900), 4.8 equivalents of 3-mercaptopropionic acid, and 4.8 equivalents of triethylamine were added to an acetonitrile solvent, followed by 24 hours at room temperature reacted Then, after adding methylene chloride to the reaction solution, it was extracted 5 times with a 10-fold diluted aqueous solution of 35% hydrogen chloride. After adding sodium sulfate to the organic layer to remove remaining water, it was evaporated to obtain a dispersant containing a compound represented by [Chemical Formula 5] (n and m refer to the molecular weight of the starting material).

(Synthesis Example 2)

In Synthesis Example 1, except that the molecular weight of the fluorene-based compound (the starting material of Scheme 1) is 1350, the reaction is performed in the same manner, and the compound represented by [Formula 5] (n and m are the starting materials molecular weight) was obtained.

(Synthesis Example 3)

First, 1 equivalent of a fluorene-based compound (starting material of Scheme 2, molecular weight 900), 4.8 equivalents of 3-mercaptoethanol, and 4.8 equivalents of triethylamine were added to an acetonitrile solvent, followed by reaction at room temperature for 24 hours made it Then, after adding methylene chloride to the reaction solution, it was extracted 5 times with a 10-fold diluted aqueous solution of 35% hydrogen chloride. Sodium sulfate was added to the organic layer to remove remaining moisture, and then evaporated to obtain an intermediate compound (intermediate in Scheme 2). Next, after putting the obtained intermediate compound, 2.54 equivalents of phosphoryl chloride, and 2.54 equivalents of triethyleneamine in a tetrahydrofuran solvent, they were reacted at room temperature for 24 hours. Thereafter, after adding deionized water to the reaction solution, the mixture was extracted three times with methylene chloride. After adding sodium sulfate to the organic layer to remove remaining water, it was evaporated to obtain a dispersant containing a compound represented by [Formula 6] (n and m refer to the molecular weight of the starting material).

(Synthesis Example 4)

In Synthesis Example 3, except that the molecular weight of the fluorene-based compound (the starting material of Scheme 2) is 1350, the reaction is performed in the same manner, and the compound represented by [Formula 6] (n and m are the starting materials molecular weight) was obtained.

(Production Example 1)

A solution containing 30 wt% of zirconia nano sol and the dispersing agent obtained in Synthesis Example 1 was added to 10 ml of tetrahydrofuran reaction solvent and reacted for 2 hours while being refluxed. Thereafter, ethyl acetate was added to the reaction solution to precipitate the surface-treated zirconia nanoparticles, and then the supernatant was discarded by centrifugation (4000 rpm, 10 minutes) and the surface-treated zirconia nanoparticles settled in the solvent were dispersed in the composition. got

(Production Example 2)

In Preparation Example 1, except for using the dispersant obtained in Synthesis Example 2 instead of Synthesis Example 1, surface treatment was performed in the same manner to obtain a composition.

(Production Example 3)

In Preparation Example 1, except for using the dispersant obtained in Synthesis Example 3 instead of Synthesis Example 1, surface treatment was performed in the same manner to obtain a composition.

(Production Example 4)

In Preparation Example 1, except for using the dispersant obtained in Synthesis Example 4 instead of Synthesis Example 1, surface treatment was performed in the same manner to obtain a composition.

(Example 1)

In the composition of Preparation Example 1, the amount of the dispersant solution was treated differently, and the functional group change on the surface of the zirconia nanoparticles was analyzed using a PM-IRRAS instrument, and shown in [Figure 2] below. Here, chloroform was used as the solvent of the composition.

Referring to the figure, the two main peaks 1464 nm ^-1 and 1567 nm ^-1 appearing in the zirconia nanoparticles represent -COO- and -OH, respectively, and appear to move to the left as the amount of the dispersant increases. As adsorption on the surface of the zirconia nanoparticles increases the distribution density of the dispersants on the surface of the particles, it is expected that hydrogen bonding occurs.

On the other hand, a new peak of 1379 nm ^-1 is found in the amount of dispersant solution treatment of 300 ul or more, which is expected to be due to the desorption of the previously adsorbed dispersant and the increase in the amount of non-bridged -OH.

On the other hand, a new peak of 1507.5 nm ^-1 is found in the treatment amount of 300 ul or more of the dispersant solution, which is a major peak found even in a single dispersant, and is intuitive evidence that the dispersant is adsorbed on the surface of the zirconia nanoparticles.

(Example 2)

In the composition of Preparation Example 1, various composite materials were prepared while changing the solvent of the composition to tetrahydrofuran, methylene chloride and chloroform, respectively. Specifically, high refractive polyester having a fluorene group was mixed with a composition obtained by using different solvents, and then dried to prepare various composite materials. All other conditions, such as the amount of the dispersant solution, were all the same. Then, the transparency of the prepared composites was visually observed.

As a result of comparison, the higher the polarity of the solvent, that is, the higher the transparency of the composite material prepared in the order of chloroform (4.1), tetrahydrofuran (4.0), and methylene chloride (3.1).

(Example 3)

High refractive index polyester having a fluorene group was mixed with the compositions of Preparation Examples 1 to 4, respectively, and then dried to prepare a composite material 1-4. Here, chloroform was used as the solvent of each composition, and the amount of the dispersant solution was the same. Separately, composite material 5 was prepared by mixing zirconia nanoparticles not treated with a dispersant in high refractive polyester having a fluorene group in a 10 wt% chloroform solvent and drying. Thereafter, the transparency of composites 1-4 and 5 was visually observed.

As a result of comparison, composites 1-4 were superior in transparency to composite 5. Of these, the transparency of composite 1 and composite 5 is shown in [Figure 3] below.

Referring to the drawing, (a) represents the transparency of the composite material 5, and (b) represents the transparency of the composite material 1. Through this, it can be seen that when using the zirconia nanoparticles in the case of surface treatment with a dispersant according to the present disclosure, the transparency is excellent compared to the case of using the zirconia nanoparticles in the case of not surface treatment.

The expression "one example" used in the present disclosure does not mean the same embodiments, and is provided to emphasize and describe different unique characteristics. However, the examples presented above are not excluded from being implemented in combination with features of other examples. For example, even if a matter described in a specific example is not described in another example, it may be understood as a description related to another example, unless there is a description contrary to or contradictory to the matter in the other example.

Terms used in this disclosure are only used to describe an example, and are not intended to limit the disclosure. In this case, singular expressions include plural expressions unless the context clearly indicates otherwise.

Claims (13)

Including a compound represented by the following [Formula 1],
[Formula 1]

X ¹ and X ² are each an aromatic ring, R ¹ , R ² , R ³ and R ⁴ are each a substituent, a, b, c and d are each an integer from 0 to 4, R ⁵ and R ⁶ are each An aliphatic chain, n and m are each an integer of 2 to 20, Y ¹ and Y ² are each a bonding group represented by the following [Formula 2], Z ¹ and Z ² are each of the following [Formula 3] or [Formula 4] It is a terminal group represented by ],
[Formula 2]

R ⁷ is an O, N or S atom, R ⁸ is an aliphatic chain, - ^* means a linking site with Z ¹ or Z ² ,
[Formula 3]

R ⁹ is an aliphatic chain;
[Formula 4]

R ¹⁰ is an aliphatic chain;
Dispersant.
According to claim 1,
X ¹ and X ² in [Formula 1] are each a benzene ring,
Dispersant.
According to claim 2,
R ⁵ and R ⁶ in [Formula 1] are each a C ₂ ~ C ₆ saturated hydrocarbon chain,
Dispersant.
According to claim 2,
R ¹ , R ² , R ³ and R ⁴ in [Formula 1] are each a halogen group, a cyano group, a nitro group, a hydroxy group, a C ₁ ~ C ₁₀ alkyl group, a C ₁ ~ C ₁₀ alkoxy group, a C ₂ ~ A C ₁₀ alkene group, a C ₂ ~C ₁₀ alkyne group, or a C ₄ ~C ₁₀ alkene group,
Dispersant.
According to claim 4,
a, b, c and d in [Formula 1] are each an integer of 0,
Dispersant.
According to claim 1,
In [Formula 2], R ⁷ is an O atom, R ⁸ is a C ₂ ~ C ₆ saturated hydrocarbon chain,
Dispersant.
According to claim 1,
R ⁹ in [Formula 3] is a C ₂ ~ C ₆ saturated hydrocarbon chain,
Dispersant.
According to claim 1,
R ¹⁰ in [Formula 4] is a C ₂ ~ C ₆ saturated hydrocarbon chain,
Dispersant.
According to claim 1,
The compound represented by [Formula 1] includes a compound represented by the following [Formula 5],
[Formula 5]

n and m are each an integer from 2 to 20,
Dispersant.
According to claim 1,
The compound represented by [Formula 1] includes a compound represented by [Chemistry 6] below,
[Formula 6]

n and m are each an integer from 2 to 20,
Dispersant.
zirconia nanoparticles surface-treated with a dispersant; and
menstruum; Including,
The dispersant is the dispersant of any one of claims 1 to 10,
composition.
According to claim 11,
The dispersant is adsorbed on the surface of the zirconia nanoparticles,
composition.
According to claim 11,
The solvent is tetrahydrofuran, methylene chloride or chloroform,
composition.

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