KR101929018B1 - Core-shell inorganic particles, preparation method thereof, and optical film containing the same - Google Patents

Abstract

The present invention relates to an inorganic particle having a core shell structure, a process for producing the inorganic particle, and an optical film comprising the inorganic particle. The inorganic particle of the core shell structure according to the present invention comprises zirconium (Zr) and aluminum By having the core surround a shell containing a lanthanide element, high refractive index and transmittance can be exhibited. In addition, the surface-treated particles of the inorganic particles are excellent in compatibility with an acrylic resin, excellent in light transmittance, exhibit a low color coordinate, and thus can be usefully used in an optical film such as a prism sheet.

Description

(Core-shell inorganic particles, preparation method thereof, and optical film containing the same)

The present invention relates to an inorganic particle having a core shell structure, a method for producing the inorganic particle, and an optical film containing the inorganic particle.

The optical sheet used for the liquid crystal display of a liquid crystal display (LCD) is composed of a diffusion plate, a diffusing film, and the like which concentrates the light spreading to the outside, thereby improving the luminance in front of the panel And the like. Here, the diffusion film diffuses the light emitted through the upper surface of the light guide plate to uniform the brightness and to widen the viewing angle. However, the light passing through the diffusion film has a problem that the front emission luminance is lowered. In order to increase the brightness deteriorated by the diffusion film, a device included in the liquid crystal is a prism sheet. However, in order to improve the performance of the prism sheet, there is a problem in that the refractive index and visible light transmittance of the prism sheet must be improved and the color coordinate must be lowered. In addition, it is difficult to develop a prism sheet because complex physical properties are required to improve reliability such as scratch resistance and change with time.

The thermoplastic acrylic resin used as a transparent material of the conventional prism sheet is widely used for various industrial products and optical devices including automobiles, household appliances, and the like because of its high light transmittance, excellent optical characteristics, molding processability, high surface hardness and mechanical strength . As described above, in order to increase the panel brightness of the liquid crystal display device, the refractive index of the resin used in the prism sheet must be high, the transparency must be excellent, and the color coordinates must be maintained at a low level. However, general high-refractive-index acrylic resin not only exhibits yellow color but also exhibits low transparency due to an increase in color coordinates due to accelerated yellowing over time due to exposure to ultraviolet rays, and has poor mechanical scratch resistance due to low mechanical strength, have. Accordingly, there has been known a method of adding an ultraviolet absorber to solve the yellowing due to ultraviolet light. However, the above method is problematic in that the brightness of the prism sheet is lowered due to the absorbent added to the acrylic resin, In the reliability test, there is a limit that the absorbent precipitates and causes defects.

Korean Patent No. 10-1189462

It is an object of the present invention to provide a material having excellent brightness and refractive index, as well as suppressing yellowing and having excellent solution stability.

Another object of the present invention is to provide a method of manufacturing the above-mentioned material.

It is still another object of the present invention to provide a high refractive index optical film comprising the above material.

Thus, in one embodiment,

A core containing zirconium (Zr) and aluminum (Al); And

There is provided an inorganic particle comprising a shell surrounding the core and containing at least one lanthanide element.

In addition, the present invention, in one embodiment,

Mixing a lanthanide element precursor solution with particles containing zirconium (Zr) and aluminum (Al) to obtain a mixture comprising a lanthanide element precursor; And

And performing a high-pressure reaction of the mixture to produce an inorganic particle having a structure in which a lanthanide element surrounds the surface of the particle containing zirconium (Zr) and aluminum (Al).

In addition, the present invention, in one embodiment,

A core containing zirconium (Zr) and aluminum (Al); And

A shell surrounding said core and containing at least one lanthanide element,

Wherein the shell is surface-treated with a compound represented by the following Chemical Formulas 1 and 2:

[Chemical Formula 1]

[Chemical Formula 1]

(2)

In the above Formulas 1 and 2,

(n은 1 내지 100으로부터 선택되는 어느 하나의 수)이고,R ₁ is hydrogen, an alkyl group having 1 to 20 carbon atoms, or

(n is any number selected from 1 to 100)

R ₂ is an alkyl group having 1 to 20 carbon atoms,

The alkyl group is substituted or unsubstituted with a carboxyl group, an aryl group having 6 to 20 carbon atoms, or an aryloxy group.

Furthermore, the present invention provides an optical film comprising the surface-treated inorganic particles.

The inorganic particles of the core shell structure according to the present invention can exhibit high refractive index and transmittance by having a structure in which a core containing zirconium (Zr) and aluminum (Al) surrounds a shell containing a lanthanide element. In addition, the surface-treated particles of the inorganic particles are excellent in compatibility with an acrylic resin and thus have high solution stability, and are excellent in an effect of suppressing yellowing of an acrylic resin, and thus can be usefully used in an optical film such as a prism sheet.

1 is a perspective view schematically showing the shape of a prism sheet.
2 is a schematic view of a triangular prism having a rounded valley portion.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the present invention, the terms "comprises," "comprising," or "comprising ", when used in this specification, designate the presence of stated features, integers, Steps, operations, elements, components, or combinations of elements, numbers, steps, operations, components, parts, or combinations thereof.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Hereinafter, the present invention will be described in detail with reference to the drawings, and the same or corresponding components are denoted by the same reference numerals regardless of the reference numerals, and a duplicate description thereof will be omitted.

The present invention relates to an inorganic particle having a core shell structure, a method for producing the inorganic particle, and an optical film containing the inorganic particle.

The optical sheet used for the liquid crystal display of a liquid crystal display (LCD) is a diffuser plate which diffuses the light to make the brightness uniform, a diffusion film, and the light which spreads to the outside is concentrated, And the like. Here, the diffusion film diffuses the light emitted through the upper surface of the light guide plate to uniform the brightness and to widen the viewing angle. However, the light passing through the diffusion film has a problem that the front emission luminance is lowered. In order to increase the brightness deteriorated by the diffusion film, a device included in the liquid crystal is a prism sheet.

The thermoplastic acrylic resin used as a transparent material of the conventional prism sheet is widely used for various industrial products and optical devices including automobiles and household appliances because of its high light transmittance, excellent optical properties, molding processability, high surface hardness and mechanical strength have. However, when the acrylic resin is exposed to light including ultraviolet rays, yellowing may occur and transparency may be lowered. In order to solve such a problem, a method of adding an ultraviolet absorber is known. However, according to the method, the brightness of the prism sheet is lowered due to the absorbent added to the acrylic resin, and the stability of the solution is low, There is a limit to cause defects.

The inorganic particles of the core shell structure according to the present invention can exhibit high refractive index and transmittance by having a structure in which a core containing zirconium (Zr) and aluminum (Al) surrounds a shell containing a lanthanide element. In addition, the surface-treated particles of the inorganic particles are excellent in compatibility with an acrylic resin and thus have high solution stability, and are excellent in an effect of suppressing yellowing of an acrylic resin, and thus can be usefully used in an optical film such as a prism sheet.

Hereinafter, the present invention will be described in detail.

Core shell  Inorganic particles of structure

The present invention provides an inorganic particle of core shell structure in one embodiment.

The inorganic particles according to the present invention include a core containing zirconium (Zr) and aluminum (Al); And a shell surrounding the core and containing at least one lanthanide element.

At this time, the core contains zirconium (Zr) as a main component, and the shape of the zirconium (Zr) is not particularly limited and may be included. For example, the zirconium (Zr) may exist in the form of zirconium (Zr), which is a metal in the core, or zirconia (ZrO ₂ ), which is an oxide. Herein, "as the main component" means at least 80 wt%, at least 90 wt%, at least 95 wt%, at least 96 wt%, at least 97 wt%, at least 98 wt%, at least 99 wt% 100% by weight, 95 to 99% by weight, 96 to 99% by weight, or 97 to 100% by weight. As an example, the core may comprise 98 +/- 1 wt% zirconia and 2 +/- 1 wt% aluminum based on 100 wt parts total.

In addition, since the core contains aluminum (Al) together with zirconium (Zr) as a main component, it can reduce the manufacturing cost of inorganic particles as compared with the case where zirconium (Zr) It is possible to easily control the light transmittance and the brightness of the core itself containing the Zr.

The content of the aluminum (Al) may be 0.1 to 30 parts by weight relative to 100 parts by weight of zirconium (Zr) contained in the core. Specifically, 0.1 to 20 parts by weight, 0.1 to 15 parts by weight 0.1 to 5 parts by weight, 0.1 to 3 parts by weight, 5 to 15 parts by weight, 10 parts by weight to 30 parts by weight, 10 parts by weight to 20 parts by weight, 20 parts by weight 30 parts by weight, 0.1 part by weight to 1 part by weight, 0.1 part by weight to 2 parts by weight, 12 parts by weight to 17 parts by weight, or 23 parts by weight to 27 parts by weight. The present invention can improve not only the processability of the inorganic particles but also the light transmittance and the luminance of the film containing the same by controlling the content of aluminum (Al) within the above range.

In addition, the core may further include chromium (Cr) together with zirconium (Zr) and aluminum (Al), and the content thereof is 0.01 to 10 parts by weight based on 100 parts by weight of zirconium (Zr) 0.01 to 5 parts by weight, 0.01 to 1 part by weight, 3 to 7 parts by weight, 5 to 10 parts by weight, or 4 to 6 parts by weight may be used. The present invention can effectively suppress the yellowing due to ultraviolet rays without causing deterioration of physical properties of the inorganic particles by further including chromium in the above content range in the core.

Furthermore, the shell contains a lanthanide element, and the kind thereof is not particularly limited as long as it improves the optical properties of the core. As one example, the shell may contain lanthanum (La), cerium (Ce), lutetium (Lu) and the like as a lanthanide element, and specifically may contain lanthanum (La). In addition, although the form of the lanthanide element is not particularly limited, it may preferably have an oxide form. For example, the lanthanide element may be lanthanide (La ₂ O ₃ ).

The content of the lanthanide element may be 0.1 to 20 parts by weight, more preferably 0.1 to 15 parts by weight, 0.1 to 10 parts by weight, 0.1 to 5 parts by weight, 1 part by weight 5 to 5 parts by weight, 5 to 10 parts by weight, 5 to 15 parts by weight, 15 to 15 parts by weight, 10 to 20 parts by weight, or 15 to 20 parts by weight.

On the other hand, the inorganic particles according to the present invention may have an average particle size of 1 nm to 100 nm, more specifically 1 nm to 100 nm, 5 nm to 80 nm, 5 nm to 60 nm, 10 nm to 40 nm, 10 Nm to 25 nm, 14 nm to 35 nm, 19 nm to 25 nm, or 25 nm to 35 nm.

Since the inorganic shell of the core shell structure according to the present invention has the above-described structure, the refractive index and brightness of the optical film including the core shell structure can be improved at the same time. Specifically, in the case of lanthanide (La ₂ O ₃ ) as a lanthanide element, since the refractive index is higher than that of zirconia (ZrO ₂ ), the inorganic particle provided with the shell containing the lanthanide element is composed of inorganic particles It is possible to have a higher refractive index in comparison with the above. Further, since the inorganic particles have a shell containing a lanthanide element, the yellowing phenomenon is improved when the surface treatment with an organic compound is performed, so that a low color coordinate can be exhibited. In addition, since particles containing zirconium (Zr) and aluminum (Al) are included as cores, the cost of raw materials is economical compared with particles composed of lanthanide (La ₂ O ₃ ) have.

Core shell  Of inorganic particles of the structure

In addition, the present invention provides a method for producing inorganic particles of the core shell structure in one embodiment.

According to the present invention,

Mixing a lanthanide element precursor solution with particles containing zirconium (Zr) and aluminum (Al) to obtain a mixture comprising a lanthanide element precursor; And

Pressure reaction of the mixture to produce an inorganic particle having a core shell structure in which the lanthanide element surrounds the surface of the particle containing zirconium (Zr) and aluminum (Al).

Hereinafter, a method for producing an inorganic particle having a core shell structure according to the present invention will be described in detail for each step.

First, the step of obtaining the mixture containing the lanthanide element precursor is a step of mixing the lanthanide element precursor solution with particles containing zirconium (Zr) and aluminum (Al) to prepare a mixture.

At this time, the lanthanide element precursor is not particularly limited as long as it contains a lanthanide element. For example, as a precursor of the lanthanide element, acetic acid in which a lanthanide element is dissolved may be used. Specifically, acetic acid in which lanthanum (La) is dissolved may be used.

The particles containing zirconium (Zr) and aluminum (Al) are not particularly limited as long as they contain zirconium (Zr) and aluminum (Al). As an example, the particles containing zirconium (Zr) and aluminum (Al) can be prepared by performing the following steps:

i) mixing a mixture of a zirconium precursor and an aluminum precursor to obtain a precursor mixture;

ii) performing a high pressure reaction of the precursor mixture; And

iii) milling the precursor mixture subjected to the high pressure reaction at a speed of 500 to 2,000 rpm to produce particles containing zirconium (Zr) and aluminum (Al).

Specifically, a zirconium (Zr) precursor and an aluminum precursor were mixed with a stirrer, and the mixture prepared using a high-pressure reactor was subjected to a high-pressure reaction at 200 ± 100 ° C. and 30 ± 1 atm, It can be obtained by milling at a speed of 1,500 rpm.

Examples of the zirconium precursor and the aluminum precursor include commercially available products such as a zirconium precursor such as zirconium acetate (ZrO (CH ₃ COO) ₂ ) or aluminum isopropoxide (Al (Oi-Pr) ₃ ). ≪ / RTI >

In addition, the mixture containing the zirconium precursor and the aluminum precursor may further include a chromium precursor by further mixing the chromium precursor when the zirconium precursor and the aluminum precursor are mixed, as the case may be.

In addition, the average size of the particles containing zirconium (Zr) and aluminum (Al) may be from 1 nm to 20 nm. The average size of the particles containing a particular zirconium (Zr) and aluminum (Al) may be 1 to ㎚ 15㎚, 2㎚ to 12㎚ or 2㎚ to 1 0 ㎚. Since the particles containing zirconium (Zr) and aluminum (Al) in the present invention constitute the core of the inorganic particles according to the present invention, the average size of the particles containing zirconium (Zr) and aluminum (Al) (Zr) and aluminum (Al) in the same manner as described above, it is possible to control the average particle size of the inorganic particles to a desired level Drying and dispersing steps can be omitted, so that workability is improved and economical efficiency due to process simplification is improved.

Next, the step of preparing the inorganic particles is a step of forming a shell on the surface of the particles containing zirconium (Zr) and aluminum (Al) contained in the mixture by performing the reaction at a high pressure of at least 1 atm, The steps include 1) performing the reaction at a high pressure of at least 1 atm, which is atmospheric pressure, and 2) milling the mixture subjected to the high-pressure reaction to induce a chemical reaction and a dispersing action.

At this time, the pressure of the high-pressure reaction is not particularly limited as long as it is a pressure higher than 1 atm which is atmospheric pressure, but it is specifically 1 atm to 50 atm, 5 atm to 50 atm, 10 atm to 40 atm, 20 atm to 40 atm, To 45 atm, from 25 atm to 35 atm, or from 28 atm to 32 atm.

In addition, the milling may be carried out by mixing the zirconium (Zr) and aluminum (Al) -containing particles with the lanthanide element precursor solution, as well as the milling method conventionally used in the art And can be applied without limitation. Specifically, the milling may be a milling process performed using a bead mill apparatus.

In addition, the milling can be performed at a speed of 500 rpm to 2,000 rpm, and more specifically, at a speed of 1,000 rpm to 2,000 rpm, 1,000 rpm to 1,500 rpm, or 1,200 rpm to 1,400 rpm.

As one example, a method for producing an inorganic particle of a core shell structure according to the present invention is a method for producing an inorganic particle by a core shell structure, which comprises mixing a mixture containing particles of zirconium (Zr) and aluminum (Al) with an acetic acid solution containing lanthanum , Milled at a temperature of 70 ± 5 ° C at a speed of 1300 ± 100 rpm for 3 ± 1 hours and the milled mixture was subjected to a high pressure reaction at 30 ± 1 atm. The solvent was then removed to remove inorganic particles of the core shell structure Can be manufactured.

Surface treated inorganic particles

In addition, the present invention provides, in one embodiment, a core comprising zirconium (Zr) and aluminum (Al); And a shell surrounding the core and containing at least one lanthanide group element, wherein the shell is surface-treated with at least one of compounds represented by the following general formulas (1) and (2) to provide:

[Chemical Formula 1]

(2)

In the above Formulas 1 and 2,

(n은 1 내지 100으로부터 선택되는 어느 하나의 수)이고,R ₁ is hydrogen, an alkyl group having 1 to 20 carbon atoms, or

(n is any number selected from 1 to 100)

R ₂ is an alkyl group having 1 to 20 carbon atoms,

The alkyl group is substituted or unsubstituted with a carboxyl group, an aryl group having 6 to 20 carbon atoms, or an aryloxy group.

Specifically, in the above formulas (1) and (2)

(n은 1 내지 50으로부터 선택되는 어느 하나의 수)이고,R ₁ is hydrogen, an alkyl group having 1 to 4 carbon atoms, or

(n is any number selected from 1 to 50)

R ₂ is an alkyl group having 1 to 10 carbon atoms,

The alkyl group may be substituted or unsubstituted with a carboxyl group, a phenyl group, a naphthyl group, an anthracenyl group, a benzyloxy group, a biphenyloxy group or a naphthyloxy group.

As one example, the compound represented by Formula 1 may be at least one compound selected from the group consisting of the following Chemical Formulas 1a to 1d:

[Formula 1a]

[Chemical Formula 1b]

[Chemical Formula 1c]

≪ RTI ID = 0.0 &

In the above formula (1d), m is any one selected from 1 to 10.

The surface-treated inorganic particles according to the present invention are improved in compatibility with an acrylic resin by surface-treating an inorganic particle surface having a core shell structure with at least one of the compounds represented by the general formulas (1) and (2) And the yellowing phenomenon of the acrylic resin is improved, so that when the surface-treated inorganic particles are used in a prism sheet, a low color coordinate can be obtained.

At this time, the content of the compounds represented by formulas (1) and (2) can be appropriately controlled within a range that does not lower the light transmittance and brightness of the surface-treated inorganic particles. Specifically, the content of the compounds represented by Formulas 1 and 2 may be 10 to 40 parts by weight based on 100 parts by weight of the core-shell inorganic particles not surface-treated, more specifically, 100 parts by weight of the core- 10 to 20 parts by weight, 15 to 30 parts by weight, 20 to 40 parts by weight, 25 to 40 parts by weight, 30 to 35 parts by weight, or 31 to 33 parts by weight,

Process for producing surface-treated inorganic particles

In addition, the present invention provides a method for producing an inorganic particle surface-treated in one embodiment.

The above manufacturing method includes a step of modifying the shell surface of the inorganic particles by reacting the inorganic particles of the core shell structure according to the present invention with at least one of the compounds represented by the formulas (1) and (2).

Specifically, the step of modifying the shell surface of the inorganic particles comprises:

Reacting the inorganic particles of the core shell structure with at least one of compounds represented by Formulas (1) and (2) to first modify the surface of the inorganic particles; And

And a step of secondarily modifying the surface of the inorganic particles by reacting at least one of the first modified inorganic particles and the compounds represented by Formulas (1) and (2).

The method for producing a surface-treated inorganic particle according to the present invention is characterized in that a mixture comprising an inorganic particle of a core shell structure and at least one of compounds represented by formulas (1) and (2) is reacted at 40 to 60 ° C for 30 minutes to 200 minutes The surface of the inorganic particles is first modified, and the primary surface-treated inorganic particles are re-married with at least one of the compounds represented by the general formulas (1) and (2) and reacted at 40 to 80 캜 for 2 hours to 4 hours, . Herein, the compounds represented by the formulas (1) and (2) may have a different structure from the compound reacted with the core shell inorganic particles during the first surface treatment.

As one example, the surface-treated inorganic particles may be first surface-treated with 2-carboxylethyl acrylate and / or acrylic acid, and o-phenylphenol ethoxy acrylate ( the surface may be subjected to a second surface treatment with o-phenylphenol ethoxy acrylate, OPPEA, butyl acrylate (BA) and / or benzyl acrylate (BZ).

Optical film

Furthermore, the present invention provides an optical film comprising the surface-treated inorganic particles.

The optical film according to the present invention is excellent in optical transmittance and brightness of the film including the surface-treated inorganic particles and low in color coordinates of the optical film, so that it can be effectively used as an optical sheet requiring high light transmittance and brightness .

Specifically, the optical film may be included in the optical sheet and used as one or more optical layers on which a micropattern is formed, and the optical layer may have various shapes such as a structure in which a triangular sectional shape is repeated according to the shape of a frame And the like.

As one example, the micropattern may be a prism pattern, wherein the optical sheet may be a prism sheet.

Further, the optical film according to the present invention may further comprise a curable resin together with the surface-treated inorganic particles. Depending on the type of the curable resin, the optical property of the optical film to be produced and the process of producing the optical film may be controlled have.

Examples of such a curable resin include 2-phenoxyethyl acrylate, benzyl acrylate, o-phenoxy phenyl ethoxy acrylate, bisphenol epoxy acrylate, fluorene diacrylate, and urethane acrylate, They may be used alone or in combination of two or more.

When the optical film according to the present invention is used as a prism sheet, the optical film may have a structure that is formulated into a prism sheet itself.

As one example, the optical film according to the present invention may be a structure that forms a repetitive pattern of a triangular prism shape including a crest portion of a bone and an acid when used as a prism sheet. As another example, in the pattern in which the triangular prism shape is repeated, at least one of the bone and the mountain-shaped vertices may be formed in a round shape.

1 is a perspective view schematically showing the shape of an optical film (hereinafter referred to as a 'prism sheet') when an optical film is used as a prism sheet.

Referring to FIG. 1, a prism sheet 100 includes a base film 110 and a pattern unit 120 disposed on the base film 110. The pattern unit 120 includes a plurality of triangular prisms 130 arranged in a structure of repeated patterns of valleys and apexes. The vertex of each of the triangular prisms 130 is a line formed by intersecting two inclined surfaces, and the sectional shape can be defined as a point. At this time, the pitch interval between adjacent triangular prisms 130 is 9 to 25 占 퐉, and the thickness of the pattern unit 120 may be in a range of 18 to 50 占 퐉.

Alternatively, the vertexes of each of the triangular prisms 130 may have a round shape, which will be described with reference to FIG.

Fig. 2 is a schematic view of a triangular prism whose stem portion has a round shape; Fig.

Referring to FIG. 2, the vertex of the triangular prism 130 may have a round shape. The effect may vary depending on the height at which the round shape of the stem is formed. That is, the first height H from the base of the triangular prism 130 to the imaginary vertex 140 and the rounded vertex 150 at the base of the triangular prism 130, The luminance and luminance uniformity effects may be varied depending on the ratio (h / H) of the second height h up to the second height h.

The shape of the prism sheet in the present invention is not particularly limited and may be applied to a prism sheet that is changed, substituted, or improved to the extent that does not depart from the ordinary knowledge in the art.

Further, the prism sheet can be applied to various optical devices. For example, it can be applied to a back light unit (BLU) of an optical device.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples.

However, the following Examples and Experimental Examples are merely illustrative of the present invention, and the present invention is not limited to the following Examples and Experimental Examples.

Example  1-3. Core shell  Preparation of inorganic particles of structure

Zirconium (Zr) precursor, zirconium acetate _{(ZrO (CH 3 COO) 2} ) solution (500 g, 30% by weight of zirconium oxide (ZrO ₂₎ containing) aluminum precursor is aluminum isopropoxide (aluminium isopropoxide, Al (Oi in -Pr) ₃₎ and chromium precursor of chromium acetate monohydrate _{(Cr 2 (OAc) 2 (} 12 ± 0.2 hours at a rate of 500 ± 20 rpm by an H ₂ O) ₂₎ is added in an amount shown in Table 1 using a stirrer Lt; / RTI > At this time, it was confirmed whether the aluminum precursor was completely dissolved. The stirred precursor mixture was subjected to a first high pressure reaction at 230 ± 2 ° C. and 30 ± 0.5 atm for 3 ± 0.2 hours. When the reaction was completed, the reaction was carried out at a rate of 1,300 ± 20 rpm using a bead mill for 3 ± 0.2 hours And car milling was performed.

After the lanthanum (La) solution dissolved in the milled mixture was added to the mixture, the secondary high pressure reaction was carried out at 70 ± 2 ℃ for 30 ± 0.5 atm and at 30 ± 0.5 atm for 3 ± 0.2 hours. When the reaction was completed, secondary milling was carried out at a speed of 1300 ± 20 rpm for 3 ± 0.2 hours to prepare an inorganic particle having a core shell structure. The content of lanthanum (La) dissolved in the acetic acid solution is shown in Table 1 below.

Zirconium precursor Aluminum precursor Chromium precursor Lanthanum precursor Example 1 98.5 wt% 1.5 wt% - 0.3 wt% Example 2 98.5 wt% 1.5 wt% - 0.5 wt% Example 3 98.5 wt% 1.5 wt% 0.1 wt% 0.3 wt%

The particle size of the inorganic particles prepared in Example 1 was measured twice using a particle size analyzer (model name: ELSZ-1000, manufacturer: Otsuka Electronics) and the average particle size was derived from the measured values. As a result, the particle size of the inorganic particles prepared in Example 1 was 1 nm to 100 nm, specifically 14 nm to 35 nm, and more specifically 10 nm to 25 nm. The average particle size of the inorganic particles was 29 ± 0.5 nm in the first measurement, 18 ± 0.5 nm in the second measurement, and the particle size distribution was 90% or more (about 75.6 ± 0.5 nm) of particles having an average particle size of 10 nm to 40 nm 0.5%).

Example  4 to 6. Preparation of surface-treated inorganic particles

(A) Primary surface treatment

Inorganic particles of the core shell structure prepared in Examples 1 to 3 were added in an amount of 27 ± 0.5 parts by weight based on 100 parts by weight of ethanol. To the solution containing the inorganic particles, 2-carboxyethyl acrylate (2- acrylate (10.8 ± 0.1 parts by weight), and dispersant (trade name: BYK-110, BYK, 2.7 ± 0.05 parts by weight) And the mixture was allowed to react for 5 minutes to prepare inorganic particles subjected to the first surface treatment with an acrylic compound.

(B) Secondary surface treatment

(O-phenylphenol ethoxy acrylate, OPPEA, 11.1 parts by weight) and butyl acrylate (BA, 1.37 parts by weight) were added to the solution containing the primary modified inorganic particles (100 parts by weight) And benzyl acrylate (BZ, 1.37 parts by weight) were added, and the reaction was carried out while raising the reaction temperature to 50 ± 2 ° C. and 70 ± 2 ° C. for 3 ± 0.2 hours. Then, the solvent of the mixture was removed to prepare secondary surface-treated inorganic particles.

The particle size of the inorganic particles (Example 4) surface-treated with the inorganic particles prepared in Example 1 was measured twice using a particle size analyzer (model name: ELSZ-1000, manufacturer: Otsuka Electronics) and the average particle size Respectively. As a result, the particle size of the inorganic particles is 1 nm to 150 nm, specifically 10 nm to 60 nm, and more specifically 15 nm to 30 nm. The average particle size of the inorganic particles was 25.5 ± 0.5 nm in the first measurement and 24 ± 0.5 nm in the second measurement, and the particle size distribution showed that particles having an average particle size of 10 nm to 30 nm accounted for more than 70% (about 72.3 ± 0.5%).

Comparative Example  One.

Zirconium (Zr) precursor, zirconium acetate _{(ZrO (CH 3 COO) 2} ) solution (500 g, 30% by weight of zirconium oxide (ZrO ₂₎ containing) aluminum precursor is aluminum isopropoxide (aluminium isopropoxide, Al (Oi in -Pr) ₃ ) were added in the amounts shown in Table 2, stirred, and subjected to a first high pressure reaction at 230 ± 5 ° C. and 30 ± 0.5 atm for 3 ± 0.2 hours to prepare inorganic particles. The inorganic particles thus prepared were dried and milled in a bead mill at a rate of 1300 ± 20 rpm for 3 ± 0.2 hours in the presence of a methanol solvent to prepare inorganic particles.

Zirconium precursor Aluminum precursor Comparative Example 1 98.5 wt% 1.5 wt%

Experimental Example  One.

The following experiment was conducted to evaluate the luminance and the liquid refractive index of the optical film containing the surface-treated inorganic particles according to the present invention.

First, the surface-treated inorganic particles prepared in Examples 4 to 6 and Comparative Example 1 were subjected to a liquid refractive index measurement of each resin composition prepared using an Abbe refractometer (Model: DR-M2, manufactured by ATAGO Company, Japan) Were measured.

Thereafter, each of the above surface-treated inorganic particles is mixed with a mixture of difunctional urethane acrylate, tetrafunctional urethane acrylate and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide ( diphenyl (2,4,6-trimethylbenxoyl) phosphine oxide, TPO) were mixed and stirred for 3 hours to prepare a coating composition. The prepared coating composition was coated on a PET film and cured using a metal lamp to obtain prism sheets having a structure in which the inorganic particles prepared in Examples 4 to 6 and Comparative Example 1 were dispersed. At this time, the prepared prism sheets had a pitch of about 21 ± 2 μm between adjacent triangular prisms, and the total average thickness of the PET film including the prism sheet was adjusted to about 87.5 ± 2 μm.

The prism sheet thus obtained was assembled into an optical module composed of a light source, a light guide plate and a diffusion sheet, and then the brightness of a prism sheet produced using a brightness meter for display (model name: BM7, manufacturer: Topcon Corporation) was measured. At this time, the relative brightness of each prism sheet was measured with the brightness measurement value of the prism sheet including inorganic particles containing only zirconium alone as 100%, and the results are shown in Table 3 below.

Composition type Solution refractive index The luminance of the prism sheet Example 4 1.6437 123 ± 1% Example 5 1.6423 125 ± 1% Example 6 1.6507 122 ± 1% Comparative Example 1 1.625 118 ± 1%

As shown in Table 3, it can be seen that the prism sheet containing the inorganic particles according to the present invention has excellent brightness and refractive index of 120 to 130% and 1.64 or more, respectively.

Experimental Example  2.

In order to evaluate the color coordinates of the optical film containing the surface-treated inorganic particles according to the present invention, the following experiment was conducted.

First, a prism sheet having a structure in which the inorganic particles prepared in Examples 4 to 6 and Comparative Example 1 were dispersed was prepared in the same manner as in Experimental Example 1. Thereafter, a laminate in which a 5.5 "BLU and a light guide plate / diffusion sheet were stacked was prepared, each of the produced prism sheets was arranged on both sides of the laminate, and then the distance between the BLU and the luminance meter was maintained at 500 mm, The color coordinates of the prism sheet were measured using a luminance meter (Model: SR-3AR, manufactured by TOPCPN).

A prism sheet having a color coordinate measured was placed in an accelerated weathering tester (Model: QUV / spray) and allowed to stand at 50 ± 2 ° C. for 15 minutes. Then, the color coordinates were measured again using the luminance meter for display, And the amount of coordinate change of the color coordinate y was derived. At this time, the coordinate change amount indicates that the higher the value, the more vulnerable to the yellowing of the sheet, and the measured results are shown in Table 4.

The amount of color coordinate change [? Y] The amount of color coordinate change [? Y] Example 4 0.0025 Example 6 0.0020 Example 5 0.0015 Comparative Example 1 0.0043

As shown in Table 4, it can be seen that the prism sheet containing the inorganic particles according to the present invention has a significantly improved color coordinate and a change amount of the color coordinate y of less than 0.003, specifically 0.0010 to 0.0026. These results show that the inorganic particles surface-treated in accordance with the present invention have improved yellowing.

Claims (16)

A core containing zirconium (Zr) and aluminum (Al); And
A shell surrounding the core and containing lanthanum (La)
Wherein the shell is surface-treated with at least one of compounds represented by the following general formulas (1) and (2):
[Chemical Formula 1]

(2)

In the above Formulas 1 and 2,
R ₁ is hydrogen, an alkyl group having 1 to 20 carbon atoms, or

(n is any number selected from 1 to 100)
R ₂ is an alkyl group having 1 to 20 carbon atoms,
The alkyl group is substituted or unsubstituted with a carboxyl group, an aryl group having 6 to 20 carbon atoms, or an aryloxy group.
The method according to claim 1,
R ₁ is hydrogen, an alkyl group having 1 to 10 carbon atoms or

(n is any number selected from 1 to 50)
R ₂ is an alkyl group having 1 to 10 carbon atoms,
Wherein the alkyl group is substituted or unsubstituted with a carboxyl group, a phenyl group, a naphthyl group, an anthracenyl group, a benzyloxy group, a biphenyloxy group or a naphthyloxy group.
The method according to claim 1,
The compound represented by the formula (1) is at least one compound selected from the group consisting of the following formulas (1a) to (1d):
[Formula 1a]

[Chemical Formula 1b]

[Chemical Formula 1c]

≪ RTI ID = 0.0 &

In the above formula (1d), m is any one selected from 1 to 10.
The method according to claim 1,
The content of aluminum (Al) is 0.1 to 30 parts by weight based on 100 parts by weight of zirconium (Zr).
The method according to claim 1,
Wherein the content of lanthanum (La) is 0.1 to 20 parts by weight based on 100 parts by weight of the core.
The method according to claim 1,
Wherein the average particle size of the inorganic particles is from 1 nm to 100 nm.
The method according to claim 1,
Wherein the core further contains chromium (Cr).
8. The method of claim 7,
When the core further contains chromium,
Wherein the content of chromium is 0.01 to 10 parts by weight per 100 parts by weight of zirconium (Zr).
The method according to claim 1,
The content of the compound represented by formulas (1) and (2) is 10 to 40 parts by weight based on 100 parts by weight of the non-surface treated inorganic particles.
Mixing a lanthanide element precursor solution with particles containing zirconium (Zr) and aluminum (Al) to obtain a mixture comprising a lanthanide element precursor; And
A step of subjecting the mixture to a high-pressure reaction to produce an inorganic particle having a structure in which a lanthanide element surrounds a particle surface containing zirconium (Zr) and aluminum (Al) ≪ / RTI >
11. The method of claim 10,
The step of preparing the inorganic particles includes:
Performing a high pressure reaction of the mixture; And
Milling the mixture subjected to the high-pressure reaction,
Wherein the milling is performed at a speed of 500 rpm to 2,000 rpm.
11. The method of claim 10,
Wherein the reaction is carried out at a pressure of 1 to 50 atm in the high-pressure reaction.
11. The method of claim 10,
The particles containing zirconium (Zr) and aluminum (Al)
Mixing a mixture of a zirconium precursor and an aluminum precursor to obtain a precursor mixture;
Performing a high pressure reaction of the precursor mixture; And
Comprising the steps of: milling a precursor mixture subjected to a high-pressure reaction to produce particles containing zirconium (Zr) and aluminum (Al).
An optical film comprising the surface-treated inorganic particle according to claim 1. delete delete

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