KR20220141824A - Liquid crystal nanocapsules and manufacturing method thereof, and liquid crystal nanocapsule dispersion and liquid crystal display device having the liquid crystal nanocapsules - Google Patents

Abstract

The present invention is a liquid crystal nanocapsule with excellent shape retention, in which liquid crystal nanocapsule dispersion (coating liquid for forming a liquid crystal display layer) containing liquid crystal nanocapsules can have good dispersibility and dispersion stability of liquid crystal nanocapsules. A liquid crystal nanocapsule is provided.
A liquid crystal nanocapsule covering a liquid crystal composition with a polymer wall, wherein the polymer wall is made of polyvinyl alcohol (PVA) resin crosslinked with glyoxal, and the liquid crystal nanocapsule has an average particle diameter of 10 to 355 nm.

Description

Liquid crystal nanocapsules and manufacturing method thereof, and liquid crystal nanocapsule dispersion and liquid crystal display device having the liquid crystal nanocapsules

The present invention relates to a liquid crystal nanocapsule, a method for producing the same, and a liquid crystal nanocapsule dispersion and a liquid crystal display device having the liquid crystal nanocapsule.

A display element using a liquid crystal capsule having a structure in which a liquid crystal composition is encapsulated in a capsule wall is known (for example, refer to Patent Document 1). The liquid crystal capsule described in patent document 1 is a micro-sized liquid crystal microcapsule whose average particle diameter is 1.1-2.1 micrometers.

However, in a display element using liquid crystal microcapsules with a micro-sized particle size, scattering of visible light increases, making it difficult to display black. Then, in order to obtain the liquid crystal display element which improved the optical characteristic, the display element which made the nano-sized liquid crystal nanocapsule whose average particle diameter is 30-150 nm is known (for example, refer patent document 2).

A display element using liquid crystal nanocapsules is promising as a display element in that it suppresses light scattering and is excellent in optical properties, and further improvement is desired in order to obtain an excellent display element.

Japanese Unexamined Patent Application Publication No. Hei 8-67878 International Publication No. 2016/035453

However, until now, display elements targeting liquid crystal nanocapsules having nano-sized particle sizes have not been obtained at a level that can be used as an actual driving element.

In the display element using liquid crystal nanocapsules, a liquid crystal display layer is formed by apply|coating the coating liquid containing liquid crystal nanocapsules on a board|substrate.

Therefore, in order to obtain a favorable liquid crystal display element, it is preferable to produce liquid crystal nanocapsule excellent in shape retentivity.

Moreover, it is preferable that the coating liquid for liquid crystal display layer formation containing liquid crystal nanocapsule is a coating liquid excellent in dispersibility of liquid crystal nanocapsule and also excellent in dispersion stability.

Therefore, the present invention is a liquid crystal nanocapsule with excellent shape retention, which can improve dispersibility and dispersion stability of liquid crystal nanocapsules in a liquid crystal nanocapsule dispersion (coating liquid for forming a liquid crystal display layer) containing liquid crystal nanocapsules. An object of the present invention is to provide a liquid crystal nanocapsule that can be

The present inventors, targeting a liquid crystal display element having liquid crystal nanocapsules having a nano-size particle size, in order to solve the above problems, the results of repeated studies on liquid crystal nanocapsules and a coating solution containing the liquid crystal nanocapsules , when a polymer crosslinked using a crosslinking agent of formaldehyde or glutaraldehyde is used as the polymer wall surrounding the liquid crystal, the liquid crystal nanocapsule as the object of the present invention cannot be obtained, and the level that can be used as a driving element is not obtained. On the other hand, when a polymer crosslinked using a glyoxal crosslinking agent is used, the liquid crystal nanocapsule as the object of the present invention is obtained, whereas a display element at a level that can be used as a driving element can be obtained. , and came to complete the present invention.

That is, this invention includes the following aspects.

[1] A liquid crystal nanocapsule covering a liquid crystal composition with a polymer wall, wherein the polymer wall is made of polyvinyl alcohol (PVA) resin crosslinked with glyoxal, and the liquid crystal nanocapsule has an average particle diameter of 10 to 355 nm. nanocapsules.

[2] The liquid crystal nanocapsule according to [1], wherein the average particle diameter is 50 to 200 nm.

[3] A method for producing liquid crystal nanocapsules having an average particle diameter of 10 to 355 nm,

A step of preparing a mixed solution obtained by mixing a liquid crystal composition, a surfactant, and a mixed material containing polyvinyl alcohol (PVA) in a solvent;

A step of preparing an emulsion from the mixed solution,

disposing the polyvinyl alcohol (PVA) around the emulsion dispersoid using a coacervation method, and

Using glyoxal, polyvinyl alcohol (PVA) is cross-linked to form a polymer wall surrounding the liquid crystal composition, and the liquid crystal nanocapsule comprising the step of manufacturing a liquid crystal nanocapsule encapsulating the liquid crystal composition in the polymer wall. manufacturing method.

[4] In the step of preparing the emulsion, the first preparing step of preparing an emulsion using the first dispersing emulsifier and the second dispersing emulsifying apparatus are used to prepare an emulsion having a smaller particle size than the obtained in the first preparing step The method for producing a liquid crystal nanocapsule according to [3], comprising a second preparation step of preparing the liquid crystal nanocapsule.

[5] The step of disposing the polyvinyl alcohol (PVA) around the emulsion dispersoid using the coacervation method is performed at a temperature near the cloud point of the polyvinyl alcohol (PVA), [ 3] or the method for producing a liquid crystal nanocapsule according to [4].

[6] The method for producing a liquid crystal nanocapsule according to any one of [3] to [5], wherein the crosslinking reaction is carried out in an acidic solution.

[7] A liquid crystal nanocapsule dispersion in which the liquid crystal nanocapsules according to [1] or [2] are dispersed in a solvent.

[8] The liquid crystal nanocapsule dispersion according to [7], wherein the liquid crystal nanocapsule dispersion further contains an additive for reducing the surface tension of the liquid crystal nanocapsule dispersion.

[9] A method for producing a liquid crystal nanocapsule dispersion in which liquid crystal nanocapsules having an average particle diameter of 10-355 nm are dispersed in a solvent,

A step of preparing a mixed solution obtained by mixing a liquid crystal composition, a surfactant, and a mixed material containing polyvinyl alcohol (PVA) in a solvent;

A step of preparing an emulsion from the mixed solution,

disposing the polyvinyl alcohol (PVA) around the emulsion dispersoid using a coacervation method, and

By using glyoxal, polyvinyl alcohol (PVA) is cross-linked to form a polymer wall surrounding the liquid crystal composition, and liquid crystal nanocapsules containing the liquid crystal composition are prepared by the polymer wall, whereby the liquid crystal nanocapsules are dissolved in the solvent. A method for producing a liquid crystal nanocapsule dispersion, comprising the step of preparing a dispersed liquid crystal nanocapsule dispersion.

[10] The method for producing a liquid crystal nanocapsule dispersion according to [9], further comprising a step of adding an additive to the liquid crystal nanocapsule dispersion to lower the surface tension of the liquid crystal nanocapsule dispersion.

[11] The method for producing a liquid crystal nanocapsule dispersion according to [9] or [10], further comprising a step of adjusting a solution amount of the liquid crystal nanocapsule dispersion with respect to the liquid crystal nanocapsule dispersion.

[12] A liquid crystal display device having a substrate, an electrode formed on the substrate, the liquid crystal nanocapsules according to [1] or [2], and an electric field applying means for applying an electric field to the liquid crystal nanocapsules via the electrode .

[13] A substrate, an electrode formed on the substrate, a liquid crystal display layer formed by applying the liquid crystal nanocapsule dispersion according to [7] or [8], and an electric field to the liquid crystal nanocapsule in the liquid crystal display layer through an electrode A liquid crystal display device having an electric field applying means to apply.

[14] The liquid crystal display device according to [13], wherein the liquid crystal display layer has a liquid crystal nanocapsule and a polymer binder made of polyvinyl alcohol (PVA).

According to the present invention, as a liquid crystal nanocapsule excellent in shape retention, in a liquid crystal nanocapsule dispersion (coating liquid for forming a liquid crystal display layer) containing liquid crystal nanocapsules, the dispersibility and dispersion stability of the liquid crystal nanocapsules can be improved. It is possible to provide liquid crystal nanocapsules with

1 is a schematic diagram showing an example of a cross section of a liquid crystal nanocapsule of the present invention.
2 is a schematic view showing an example for explaining the liquid crystal nanocapsules of the present invention and a method for producing a liquid crystal nanocapsule dispersion containing the liquid crystal nanocapsules.
Fig. 3 is a schematic diagram for explaining the step (II) of Fig. 2 in more detail.
Fig. 4 is a schematic diagram showing an example of a cross section of a liquid crystal display element having a liquid crystal nanocapsule of the present invention.
5 : is a photograph which shows the state of a dark field at the time of not applying a voltage using the liquid crystal display element of this invention.
6 : is a photograph which shows the state of the bright field when a voltage is applied using the liquid crystal display element of this invention.
7 : is a photograph which shows the cross-sectional SEM image of the liquid crystal display element of (Example 1-DE).
Fig. 8 is a photograph showing a cross-sectional SEM image of the liquid crystal display element of (Example 1-DE-1).
9 is a photograph showing a cross-sectional SEM image of the liquid crystal display element of (Comparative Example 1-DE).
Fig. 10 is a graph showing the measurement result of the VT curve of the liquid crystal display element of (Example 1-DE).
It is a graph which shows the measurement result of the VT curve of the liquid crystal display element of (Example 6-DE).
12 is a graph showing the measurement result of the VT curve of the liquid crystal display element of (Example 27-DE).

Hereinafter, the liquid crystal nanocapsule of the present invention and its manufacturing method, and the liquid crystal nanocapsule dispersion and liquid crystal display device having the liquid crystal nanocapsule will be described in detail. It is an example as an aspect, and is not specified by these content.

(Liquid crystal nanocapsule)

In the liquid crystal nanocapsule of the present invention, the liquid crystal composition is covered with a polymer wall.

The polymer wall is made of polyvinyl alcohol (PVA) resin crosslinked with glyoxal.

The average particle diameter of the liquid crystal nanocapsules of the present invention is 10-355 nm.

The liquid crystal nanocapsule of the present invention is characterized in that the polymer wall containing the liquid crystal composition is formed of a PVA resin crosslinked using glyoxal. The liquid crystal nanocapsule of the present invention becomes a liquid crystal nanocapsule excellent in shape retention. In addition, the coating liquid containing the liquid crystal nanocapsules has good dispersibility of the liquid crystal nanocapsules and is excellent in dispersion stability.

A preferred embodiment of the liquid crystal nanocapsule of the present invention includes a liquid crystal composition containing a liquid crystal material, a liquid crystal nanocapsule comprising a surfactant and a polymer wall.

An example of a schematic diagram showing a cross section of the liquid crystal nanocapsule of the present invention is shown in FIG. 1 . In the liquid crystal nanocapsules 1 , a liquid crystal composition 2 containing a liquid crystal material is covered with a surfactant film 3 and a polymer wall 4 . The polymer wall 4 is made of polyvinyl alcohol (PVA) resin crosslinked with glyoxal.

Hereinafter, each component of the liquid crystal nanocapsule of the present invention will be described in detail.

<Liquid crystal composition>

A liquid crystal composition contains a liquid crystal material, and may optionally further contain additives, such as an optically active compound, antioxidant, a ultraviolet absorber, and a dichroic dye. Here, the liquid crystal material refers to a material composed of one or two or more liquid crystal components (liquid crystal compounds).

A liquid crystal material will not be specifically limited if it is a material containing the liquid crystal component which shows liquid crystal property. Moreover, there is no restriction|limiting in particular as a kind of liquid crystal, According to the objective, it can select suitably, For example, a nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal, a chiral nematic liquid crystal, etc. are mentioned.

Content of the liquid crystal composition in the liquid crystal nanocapsule of this invention is not restrict|limited in particular, Although it can select suitably according to the objective, 33-90 mass % is preferable with respect to the total amount of a liquid crystal display layer. If it is within the range of the encapsulation amount, sufficient liquid crystal performance can be obtained, and the relative thickness of the polymer wall becomes sufficient, and the shape retention stability of the liquid crystal nanocapsule becomes good.

<Surfactant>

The surfactant used when preparing the liquid crystal nanocapsules of the present invention is not particularly limited and can be appropriately selected depending on the purpose. it is preferable

In addition, surfactant may use not only one type of use but combining multiple types of surfactant by arbitrary ratios.

In the present invention, it is preferable to use a nonionic surfactant which is advantageous in electrical characteristics.

Specific examples of the surfactant include Surfynol 104 (manufactured by Nisshin Chemical Industries, Ltd.), Surfynol 420 (manufactured by Nisshin Chemical Industries, Ltd.), Surfynol 440 (manufactured by Nisshin Chemical Industries, Ltd.), Surfynol SEF (manufactured by Nisshin Chemical Industries, Ltd.) Kugoku Kogyo Co., Ltd.), OLFINE E1010 (Nissin Chemical Industry Co., Ltd. make), etc. are mentioned, Especially, it is preferable to use Surfynol 104.

<Polymer wall>

The polymer wall is made of polyvinyl alcohol (PVA) resin crosslinked with glyoxal.

By the coacervation method described later, PVA gathers on the surface of the liquid crystal nanoemulsion dispersoid made of the liquid crystal composition so as to surround the liquid crystal composition, and a closed curved polymer wall (also referred to as a capsule wall) is formed.

In this invention, there is no restriction|limiting in particular as a kind of PVA, According to the objective, various PVA from which molecular weight and saponification rate differ can be selected suitably.

In addition, PVA not only contributes as a component of the polymer wall surrounding the liquid crystal for forming the liquid crystal nanocapsule, but also contributes as a polymer binder component constituting the liquid crystal display layer, as will be described later.

As a crosslinking agent for crosslinking PVA, glyoxal is used. Thereby, liquid crystal nanocapsules excellent in shape retention properties can be produced, as will be apparent also in Examples to be described later. In addition, the liquid crystal nanocapsule dispersion in which the liquid crystal nanocapsules are dispersed has excellent dispersibility and dispersion stability, and a liquid crystal display device having a liquid crystal display layer formed by coating the liquid crystal nanocapsule dispersion liquid has good optical properties, It becomes a display element of the level which can be used as an element.

It is preferable that 10-100 mass % of glyoxal is contained with respect to PVA. It is because sufficient crosslinking effect is acquired as it is in the said range.

It is preferable to add 10-50 mass % of PVA with respect to a liquid crystal composition. It is because a liquid crystal composition can fully be contained in it being in the said range, and shape retentivity of a liquid crystal nanocapsule becomes favorable.

The thickness of the polymer wall of the liquid crystal nanocapsule is preferably 1 to 25% of the radius of the liquid crystal nanocapsule, more preferably 3 to 21%.

<Characteristics of liquid crystal nanocapsules>

From a viewpoint of display quality, the average particle diameter of a liquid crystal nanocapsule is 10-355 nm.

It is more preferable that the average particle diameter of a liquid crystal nanocapsule is 50-200 nm. If the average particle size is within the above range, the problem that the liquid crystal nanocapsule has a large particle size and scatters visible light and decreases contrast can be effectively prevented can be effectively prevented.

Here, the average particle diameter of the liquid crystal nanocapsule is a sample solution circulated at a circulation rate of 1 and a stirring rate of 2 using a scattering particle size distribution measuring device LA-960 (manufactured by Horiba Seisakusho) at 25°C. It is an average value of the diameters of the emulsion or liquid crystal nanocapsules measured under conditions in which various sample concentrations are adjusted so that the transmittance of the semiconductor laser (650 nm) and the light emitting diode (405 nm) is 90.0% or less. The particle size refers to a diameter calculated from the volume distribution.

(Manufacturing method of liquid crystal nanocapsule)

The manufacturing method of the liquid crystal nanocapsule of the present invention,

(I) a step of preparing a mixed solution formed by mixing a liquid crystal composition, a surfactant, and a mixed material containing polyvinyl alcohol (PVA) in a solvent;

(II) a step of preparing an emulsion from the mixed solution,

(III) disposing polyvinyl alcohol (PVA) around the emulsion dispersoid using a coacervation method, and

(IV) using glyoxal to cross-link polyvinyl alcohol (PVA) to form a polymer wall surrounding the liquid crystal composition, and prepare a liquid crystal nanocapsule encapsulating the liquid crystal composition as the polymer wall.

Hereinafter, each process is demonstrated in detail.

<(I) step: step of preparing a mixed solution>

The solvent used in (I) is not particularly limited and may be appropriately selected depending on the purpose, for example, pure water such as ion-exchange water, ultra-filtration water, reverse osmosis water, distilled water, or Water, such as ultrapure water, is mentioned.

Moreover, you may use the mixed solvent which added water, water-soluble solvents, such as alcohol miscible with water, as needed.

Here, as a water-soluble solvent, alcohol solvents, such as methanol, ethanol, 2-propanol, 2-methyl-1- propanol, 1-butanol, 2-methoxyethanol, are mentioned, for example.

When preparing the mixed solution in the above (I), the liquid crystal composition, surfactant, and polyvinyl alcohol (PVA) are, for example, from 2 to 20:0.02 to 2:0.2 to 100 parts by mass of the total amount of the mixed solution. It is preferable to mix in the ratio of 10 mass parts.

In addition, from the viewpoint of preparing a liquid crystal nanocapsule dispersion with good applicability, when preparing a mixed solution, the liquid crystal composition, surfactant, and polyvinyl alcohol (PVA) are added to 100 parts by mass of the total amount of the mixed solution, for example, It is more preferable to mix in the ratio of 5-20:0.4-2:3-10 mass parts.

<Step (II): Step of preparing emulsion>

Preparing an emulsion means preparing a dispersion system solution in which both the dispersoid and the dispersion medium are liquid.

In this specification, the whole solution in which the emulsion dispersoid is disperse|distributed in the dispersion medium (referring to the solvent in an emulsion preparation process) is called emulsion dispersion liquid.

In addition, in this specification, the emulsion dispersoid is also only referred to as an emulsion.

The emulsion dispersoid (emulsion) is dispersed in the dispersion medium, and more specifically, the emulsion dispersoid is dispersed in the dispersion medium in a state where the periphery of the liquid crystal is covered with a surfactant.

In said (II), as a method of preparing an emulsion, the method of producing an emulsion using a dispersion-type emulsification apparatus is mentioned.

The dispersion type emulsifier is not particularly limited as long as an emulsion having a desired particle size is obtained, and may be appropriately selected depending on the purpose. A homogenizer can also be used. Moreover, there is no restriction|limiting in particular also in the dispersion method, For example, you may use any dispersion method of stirring, ultrasonic wave, and high pressure.

In the present invention, various types of dispersion type emulsification apparatuses such as a high-speed homogenizer, an ultrasonic homogenizer, a high-pressure homogenizer, and a homomixer can be used as the dispersion type emulsification apparatus.

In the above (II), as a more preferable embodiment of the step of preparing the emulsion, the first preparing step of preparing an emulsion using the first dispersing emulsifying apparatus, and the first preparing using the second dispersing emulsifying apparatus The emulsion preparation process including the 2nd preparation process of preparing the emulsion smaller than the particle diameter obtained by the preparation process is mentioned.

The first and second dispersion type emulsifiers are not particularly limited as long as an emulsion having a desired particle size is obtained. For example, the high-speed homogenizer, ultrasonic homogenizer, high-pressure homogenizer, homomixer, etc. Various dispersion type emulsification apparatuses can be used in combination as appropriate.

As a more preferred embodiment of the step of preparing the emulsion, for example, an emulsion is prepared with a high-speed homogenizer, and then a smaller emulsion is made using a high-pressure homogenizer that further applies pressure to the particles to form fine particles. An emulsion preparation step of producing

For example, in order to produce the emulsion of the desired particle size of the present invention by using a high-speed homogenizer and a high-pressure homogenizer together, the conditions of the high-speed homogenizer include 1,500 to 30,000 rpm, 10 minutes to 2 hours of stirring. It is preferable, and it is more preferable to stir at 10,000 to 20,000 rpm for 30 minutes or more, and as the conditions of the high-pressure homogenizer, it is preferable to treat 1 to 20 times at 10,000 to 30,000 psi, and 15,000 to 30,000 psi. It is more preferable to process 1 to 20 times, and more preferably to process 3 to 10 times at 20,000 to 25,000 psi.

<(III) process: coacervation process>

Coacervation refers to a phenomenon in which PVA gathers around a liquid crystal composition under an emulsion dispersion at a predetermined temperature.

In the above (III), the temperature in the coacervation method is preferably in the vicinity of the cloud point of PVA.

By setting the temperature of the emulsion dispersion to be near the cloud point of PVA, PVA can be gathered around the emulsion dispersoid.

Here, the cloud point of PVA means the temperature at which PVA begins to aggregate in water, and the cloud point of PVA differs with the molecular weight and saponification rate of PVA.

Therefore, in the present invention, by setting the solution temperature of the emulsion dispersion in the coacervation step near the cloud point of the PVA to be used, it is possible to effectively arrange the PVA around the emulsion dispersoid.

More specifically, when the solution temperature of the emulsion dispersion is set near the cloud point of PVA, solubility in water decreases, so that PVA precipitates. When the PVA is precipitated, if a liquid crystal nanoemulsion covered with a surfactant is present, the PVA is adsorbed to the surface of the liquid crystal nanoemulsion dispersoid. Therefore, in the present invention, the PVA can be effectively disposed around the liquid crystal nanoemulsion dispersoid by the coacervation step.

For example, when the PVA is Poval 26-80 (manufactured by Kuraray) used in Examples, it is preferable to set the solution temperature of the emulsion dispersion in the coacervation step to 40°C or higher. When performing coacervation using PVA of Poval 26-80, it is preferable to stir at the temperature of 40 degreeC or more, 1 to 24 hours, and stirring conditions of 50-300 rpm, and also at the temperature of 40 degreeC or more, 10-24 It is more preferable to stir under stirring conditions of about 100 rpm for a period of time.

<Step (IV): Step of manufacturing liquid crystal nanocapsules>

It is preferable that the crosslinking reaction in said (IV) is performed under acidic conditions.

As acidic conditions, it is preferable that pH exists in the range of 1-5, and it is more preferable that pH is about 3.

Therefore, as a more preferable embodiment of the step in the crosslinking reaction of (IV) above, after the step (III), an acidic solvent is added together with glyoxal to the emulsion dispersion, and the emulsion dispersion is an acidic solution. Below, the process of performing crosslinking reaction of glyoxal and PVA is mentioned.

Here, the type of the acidic solvent added together with glyoxal is not particularly limited as long as the emulsion dispersion can be made acidic. For example, an organic acid or an inorganic acid can be used, but it is more preferable to use an inorganic acid.

There is no restriction|limiting in particular as an inorganic acid, Although it can select according to the objective, For example, hydrochloric acid, acetic acid, sulfuric acid etc. can be used, Among these, hydrochloric acid is more preferable.

The steps (I) to (IV) will be described in more detail with reference to FIG. 2 .

Step (I) of FIG. 2 : A mixed solution 10 is prepared by mixing a mixed material containing polyvinyl alcohol (PVA) (a), a surfactant (b) and a liquid crystal composition (c) in a solvent.

Step (II) of FIG. 2 : Prepare an emulsion dispersoid (emulsion) 11 from the mixed solution. The emulsion dispersoid 11 is dispersed in the emulsion dispersion 12 .

Step (III) of FIG. 2 : A polyvinyl alcohol (PVA) 13 is placed around the emulsion dispersoid 11 using a coacervation method.

Step (IV) of Fig. 2: After step (III), glyoxal (d) and hydrochloric acid (e) are added to the emulsion dispersion 12 to cause a crosslinking reaction between glyoxal and PVA in an acidic solution, By forming the polymer wall 14 surrounding the liquid crystal composition, the liquid crystal nanocapsule 15 encapsulating the liquid crystal composition into the polymer wall is prepared. The liquid crystal nanocapsules 15 are dispersed in the liquid crystal nanocapsule dispersion liquid 16 .

Further, a more preferred embodiment of the step (II) in FIG. 2 will be described with reference to FIG. 3 . In Fig. 3, in the first preparation step (II-1), an emulsion is prepared using a high-speed homogenizer, and thereafter, in the second preparation step (II-2), a high-pressure homogenizer is used. An emulsion smaller than the particle size obtained in the first preparation step is prepared.

(Liquid crystal nanocapsule dispersion)

In the liquid crystal nanocapsule dispersion of the present invention, the liquid crystal nanocapsules of the present invention prepared as described above are dispersed in a solvent.

By the process (IV), the liquid crystal nanocapsule dispersion 16 in which the prepared liquid crystal nanocapsules 15 are dispersed can be obtained.

The liquid crystal nanocapsule dispersion of the present invention is used as a coating liquid for forming a liquid crystal display layer. The liquid crystal display layer is formed by coating the liquid crystal nanocapsule dispersion on a support substrate and forming a film.

It is more preferable to add an additive for reducing the surface tension of the liquid crystal nanocapsule dispersion to the liquid crystal nanocapsule dispersion of the present invention.

＜Additives＞

The additive added to the liquid crystal nanocapsule dispersion of the present invention is an additive capable of reducing the surface tension of the liquid crystal nanocapsule dispersion. By adding such an additive, the applicability of the liquid crystal nanocapsule dispersion can be further improved, and a liquid crystal display layer having no coating unevenness can be formed. And as shown also in the Example mentioned later, the liquid crystal display element which has a liquid crystal display layer without coating unevenness shows a favorable V-T curve and contrast, becomes a liquid crystal display element which shows outstanding white luminance.

The additive is not particularly limited as long as it is an additive capable of reducing the surface tension of the liquid crystal nanocapsule dispersion, and for example, a siloxane-based additive is preferable as an additive.

The siloxane-based additive is not particularly limited as long as it is an additive having a siloxane structure, and may be appropriately selected according to the purpose. For example, BYK-345, BYK-3455, BYK-346, BYK-347, BYK-348, BYK -349, BYK-378 (above, manufactured by Big Chemie Japan), Dynol 960 (manufactured by Nisshin Chemical Industries, Ltd.), Dynol 980 (manufactured by Nisshin Chemical Industries, Ltd.), KF-6011 (manufactured by Nisshin Chemical Industries or Shin-Etsu) Siloxane type additives, such as silicone company make), KF-354L (made by Shin-Etsu Silicone Co., Ltd.), and KF-643 (made by Shin-Etsu Silicone Co., Ltd.), are mentioned.

(Method for preparing liquid crystal nanocapsule dispersion)

The method for preparing the liquid crystal nanocapsule dispersion of the present invention,

(I) a step of preparing a mixed solution formed by mixing a liquid crystal composition, a surfactant, and a mixed material containing polyvinyl alcohol (PVA) in a solvent;

(II) a step of preparing an emulsion from the mixed solution,

(III) disposing polyvinyl alcohol (PVA) around the emulsion dispersoid using a coacervation method, and

(IV) by using glyoxal to cross-link polyvinyl alcohol (PVA) to form a polymer wall surrounding the liquid crystal composition, and to prepare liquid crystal nanocapsules encapsulating the liquid crystal composition in the polymer wall, so that the liquid crystal nanocapsules in the solvent and a step of preparing a dispersed liquid crystal nanocapsule dispersion.

The detailed description of each step of (I) to (IV) is the same as described in the section (Method for producing liquid crystal nanocapsules).

As a more preferred embodiment of the method for producing a liquid crystal nanocapsule dispersion, a method for producing a liquid crystal nanocapsule dispersion in which the step (V) or (VI) is further performed in addition to the steps (I) to (IV), or A method for producing a liquid crystal nanocapsule dispersion in which the steps (V) and (VI) are performed in addition to the steps (I) to (IV) described above.

(V) A step of adding an additive to the liquid crystal nanocapsule dispersion for lowering the surface tension of the liquid crystal nanocapsule dispersion.

(VI) A step of adjusting the solution amount of the liquid crystal nanocapsule dispersion with respect to the liquid crystal nanocapsule dispersion.

<Step (V): Step of adding an additive to the liquid crystal nanocapsule dispersion>

The additive of (V) is the same as described in the <additive> column of the (liquid crystal nanocapsule dispersion) column.

The additive is preferably added in a proportion of 0.01 to 0.2 mass% with respect to the liquid crystal nanocapsule solution.

<Step (VI): Step of adjusting the solution amount of the liquid crystal nanocapsule dispersion>

In the above (VI), adjusting the solution amount of the liquid crystal nanocapsule dispersion means coating the liquid crystal nanocapsule dispersion on a support substrate to form a liquid crystal display layer, so that the coating of the liquid crystal display layer is prevented or the liquid crystal display layer is coated. For the purpose of uniform dispersion of the liquid crystal nanocapsules in the liquid crystal nanocapsule, it refers to adjusting the solution amount so that the ratio (eg, volume ratio) of the liquid crystal nanocapsules occupied in the liquid crystal nanocapsule dispersion is within a desired range.

More specifically, adjusting the solution amount means reducing the amount of the solution by using a method such as concentration or increasing the amount of the solution by adding a solvent.

For example, when preparing the emulsion in the above (II), a better emulsion can be produced when the concentration of the mixed material in the mixed solution is lower than the higher concentration. Therefore, in the above (I), the mixed material is dispersed using a slightly larger amount of the solvent. So, for example, if the amount of the liquid crystal nanocapsule dispersion obtained in (VI) is too large compared to the ratio of the prepared liquid crystal nanocapsules, reduce the amount of the solution by using a method such as concentration. let it be

When reducing the amount of the solution, for example, as conditions for concentrating the solution, for example, using an evaporator, it is preferable to carry out under the conditions of 30 to 50 Torr, 30 to 50 ° C, and 50 to 150 rpm, Moreover, it is more preferable to carry out under conditions of about 40 Torr, 40 degreeC, and 100 rpm.

In the method for producing a liquid crystal nanocapsule dispersion, the liquid crystal composition, surfactant, polyvinyl alcohol (PVA), and each type and addition amount (content) of the solvent are appropriately adjusted by adjusting the dispersibility of the liquid crystal nanocapsule and the coating property at the time of film formation This excellent liquid crystal nanocapsule dispersion can be prepared.

In addition, as described in the step (V), when an additive is added to the liquid crystal nanocapsule dispersion, a liquid crystal nanocapsule dispersion having more excellent applicability can be prepared.

However, even without adding an additive, if the surfactant is contained in a certain amount or more, for example, if the surfactant is contained in 0.5 mass% or more in the liquid crystal nanocapsule dispersion, a liquid crystal nanocapsule dispersion with good applicability can be prepared.

Further, as described in the step (VI), when the liquid crystal nanocapsule dispersion is applied to form a liquid crystal display layer, for example, a concentration step of reducing the amount of the solution may be performed.

On the other hand, by appropriately adjusting the respective contents of the liquid crystal composition, surfactant, polyvinyl alcohol (PVA), and solvent, the liquid crystal nanocapsule dispersion obtained in step (IV) can be used as a coating solution as it is without performing a concentration step. A liquid crystal nanocapsule dispersion that can be used may be prepared.

From the viewpoint of producing a good emulsion, as described above, it is preferable to prepare a liquid crystal nanocapsule dispersion using a slightly large amount of solvent, and then to carry out the concentration step described in step (VI) above.

On the other hand, from the viewpoint of producing a liquid crystal nanocapsule dispersion having good applicability, it is preferable to prepare a liquid crystal nanocapsule dispersion in which the liquid crystal nanocapsule dispersion obtained in the step (IV) can be used as it is as a coating solution without performing a concentration step. desirable.

In addition, for example, when preparing a liquid crystal nanocapsule dispersion that does not undergo a concentration step, in order to obtain a liquid crystal nanocapsule dispersion excellent in applicability, a liquid crystal composition, a surfactant, and polyvinyl alcohol (PVA) are mixed when preparing a mixed solution. It is preferable that a ratio is 5-20:0.4-2:3-10 mass parts with respect to 100 mass parts of total amounts of a mixed solution, for example.

Hereinafter, the method for preparing the liquid crystal nanocapsule dispersion of the present invention will be described in more detail with reference to FIG. 2 .

As described above, the liquid crystal nanocapsule dispersion 16 in which the liquid crystal nanocapsules 15 are dispersed can be obtained by the process (IV) of FIG. 2 .

After that, the liquid crystal nanocapsule dispersion 16 may be subjected to the step (V) or step (VI) in FIG. 2, or the step (V) and step (VI) in FIG. 2 may be performed.

Step (V) of FIG. 2 : Adjust the amount of the solution of the liquid crystal nanocapsule dispersion 16 . In addition, in FIG. 2, the case where the quantity of a solution was reduced by concentration was shown. Thereby, the dispersion state of the liquid crystal nanocapsule in a liquid crystal display layer can be adjusted more preferably.

Step (VI) of FIG. 2 : By adding the additive (f) to the liquid crystal nanocapsule dispersion 16 , the liquid crystal nanocapsule dispersion 17 containing the additive in which the liquid crystal nanocapsules 15 are dispersed is prepared.

The kind of additive to be added is as described above.

(liquid crystal display element)

The liquid crystal display device of the present invention has a substrate, an electrode formed on the substrate, the liquid crystal nanocapsule of the present invention described above, and an electric field applying means for applying an electric field to the liquid crystal nanocapsule of the present invention via the electrode.

In addition, the liquid crystal display device of the present invention includes a substrate, an electrode formed on the substrate, a liquid crystal display layer formed by applying the liquid crystal nanocapsule dispersion of the present invention described above, and a liquid crystal nanocapsule of the present invention in the liquid crystal display layer through the electrode and an electric field applying means for applying an electric field to the .

As a more preferred embodiment of the liquid crystal display device of the present invention, a set of substrates disposed to face each other, electrodes formed on one or both of the opposing surfaces of each set of substrates, and the substrates of the present invention disposed between the substrates liquid crystal nanocapsules and a liquid crystal display device having an electric field applying means for applying an electric field to the liquid crystal nanocapsule of the present invention via an electrode.

Further, as a more preferred embodiment of the liquid crystal display element of the present invention, a set of substrates arranged to face each other, an electrode formed on one or both of the opposing surfaces of each of the set of substrates, and a bone disposed between the substrates and a liquid crystal display device having a liquid crystal display layer formed by applying the liquid crystal nanocapsule dispersion of the present invention, and an electric field applying means for applying an electric field to the liquid crystal nanocapsule of the present invention in the liquid crystal display layer through an electrode.

The liquid crystal display element of this invention may arrange|position a polarizing plate on the outer side of a board|substrate. The number of polarizing plates may be one or two sheets may be sufficient as them. Moreover, the liquid crystal display element of this invention may arrange|position a reflecting plate on the outer side of a board|substrate.

The film thickness of the liquid crystal display layer having the liquid crystal nanocapsules of the present invention may be appropriately selected by considering the refractive index anisotropy of the liquid crystal to be used, the content rate of the liquid crystal nanocapsules, etc., but for example, 0.2 to 10 μm is preferable, Moreover, 0.5-6 micrometers is more preferable. When the film thickness is too thin, the polarization of the liquid crystal display layer is weak when a voltage is applied, and the white luminance is lowered. to be.

The liquid crystal display layer can be formed, for example, by applying the liquid crystal nanocapsule dispersion of the present invention on a substrate, and drying and firing the coating layer.

As a preferred embodiment of the liquid crystal display layer, a liquid crystal display layer having a polymer binder made of liquid crystal nanocapsules and polyvinyl alcohol (PVA) is mentioned.

PVA contained in the mixed material not only contributes as a component of the polymer wall surrounding the liquid crystal for forming the liquid crystal nanocapsule, but also contributes as a polymer binder component constituting the liquid crystal display layer.

A liquid crystal display layer in which liquid crystal nanocapsules are dispersed in a polymer binder made of PVA is formed by applying a liquid crystal nanocapsule dispersion in which liquid crystal nanocapsules and a polymer binder component made of PVA are mixed on a substrate, and drying and firing the applied layer. can be formed

As a means for application|coating, a bar coater, a gravure coater, a knife coater, a die coater, a spray coater, etc. can be used, for example.

The film thickness of the liquid crystal display layer can be adjusted according to, for example, the size of the solid content contained in the liquid crystal display layer and the size of the mechanism of the coater to be used (eg, the size of the grooves in the bar in the bar coater). .

As a material of the board|substrate used by this invention, glass and a plastic board|substrate are mentioned, for example, Each of a set of board|substrates may be made of the same material or different materials may be sufficient as it. Moreover, although it is preferable that a board|substrate is transparent, it may be opaque. In one set of board|substrates, it is preferable that at least one is transparent.

The electrode used in the present invention is preferably a transparent electrode, but may be opaque. When electrodes are formed on both sides of a set of substrates, it is preferable that at least one of them is transparent. As a transparent electrode, an ITO electrode is used, for example. Even if the electrode is formed in the whole surface of a board|substrate, even if it is formed in pattern shape, either is not cared about. In one set of board|substrates, when an electrode is formed only in one leg, it is preferable that the electrode is a comb-tooth-shaped electrode.

An example of the cross section of the liquid crystal display element which has the liquid crystal nanocapsule of this invention is shown in FIG.

As shown in Fig. 4, in the liquid crystal display element 20 of the present invention, a liquid crystal display layer 23 having liquid crystal nanocapsules 22 is provided between a pair of supporting substrates 21 provided to face each other. have. An electrode 24 is provided on one supporting substrate.

In addition, in FIG. 4 , the liquid crystal display layer 23 in which a polymer binder made of PVA fills the gap between the liquid crystal nanocapsules 22 is shown.

A liquid crystal display device having the configuration shown in FIG. 4 having the liquid crystal nanocapsule of the present invention is prepared, a polarizing plate is attached to the liquid crystal display device, and the state when voltage is applied and not applied is shown in FIGS. 5 and 6 . . In addition, the specific manufacturing method of a liquid crystal display element is described in the following Example.

Fig. 5 is a photograph showing a dark field state when no voltage is applied using the liquid crystal display element of the present invention, and Fig. 6 is when a voltage is applied using the liquid crystal display element of the present invention. It is a photograph showing the state of the bright field of

Example

The present invention will be described in more detail below by way of examples, but the scope of the present invention is not limited to these examples.

[PVA purification]

(Example a-1)

In a 200 mL beaker, 9 g of distilled water and 81 g of methanol were mixed, and 10 g of PVA (Poval 26-80: manufactured by Kuraray Co., Ltd.) was added and stirred for 1 hour to form a slurry. Then, the solid content was filtered off, and 90 g of methanol wash|cleaned the obtained solid content. After washing, it dried under reduced pressure at 40°C to obtain purified PVA.

[Preparation of primary emulsion dispersion]

(Example b-1)

In a 200 mL beaker, 94 g of distilled water was added to dissolve 1.3 g of purified PVA, and 0.1 g of a surfactant (Surfynol 104: manufactured by Nisshin Chemical Industry Co., Ltd.) was added and stirred to dissolve. 4.6 g of liquid crystal (LCT-13-2314: manufactured by Merck) was added to the obtained aqueous solution, and stirred with a high-speed homogenizer (Biomixer BM-2: manufactured by Nippon Seiki Seisakusho Co., Ltd.) at a rotational speed of 18,000 rpm for 1 hour. , 100 g of a primary emulsion dispersion having an average particle diameter of the emulsion of 298 nm was obtained.

(Example b-2)

100 g of a primary emulsion dispersion was obtained in the same manner as in Example b-1, except that the amount of the surfactant used in Example b-1 was 0.5 g (average particle diameter of 278 nm).

Here, in Example b-2, the usage-amount of a solvent (distilled water) was adjusted by the amount of usage-amount of surfactant increased compared with Example b-1 (in Example b-2, the usage-amount of distilled water was set to 93.6g) ), the total amount of the primary emulsion dispersion was 100 g.

In addition, also in the following Examples, in order to match the total amount of emulsion dispersion liquid in each Example, the usage-amount of solvent (distilled water) was changed suitably.

(Example b-3)

A primary emulsion dispersion was obtained in the same manner as in Example b-1 except that the surfactant of Example b-1 was changed to Surfynol 420 (manufactured by Nisshin Chemical Industry Co., Ltd.) (average particle size of 308 nm).

(Example b-4)

A primary emulsion dispersion was obtained in the same manner as in Example b-1 except that the surfactant of Example b-1 was changed to Surfynol 440 (manufactured by Nisshin Chemical Industry Co., Ltd.) (average particle size: 160 nm).

(Example b-5)

A primary emulsion dispersion was obtained in the same manner as in Example b-1 except that the surfactant of Example b-1 was changed to Surfynol SE-F (manufactured by Nisshin Chemical Industry Co., Ltd.) (average particle size of 276 nm).

(Example b-6)

A primary emulsion dispersion was obtained in the same manner as in Example b-1 except that the surfactant of Example b-1 was changed to OLFINE E1010 (manufactured by Nisshin Chemical Industry Co., Ltd.) (average particle size of 351 nm).

(Example b-7)

1 in the same manner as in Example b-1, except that 87.2 g of distilled water used in Example b-1, 2.6 g of purified PVA, 1.0 g of surfactant, and 9.2 g of liquid crystal were used. 100 g of a tea emulsion dispersion was obtained (average particle diameter of 283 nm).

(Example b-8)

100 g of a primary emulsion dispersion was obtained in the same manner as in Example b-7, except that the amount of the surfactant used in Example b-7 was 0.9 g (average particle size of 284 nm).

(Example b-9)

100 g of a primary emulsion dispersion was obtained in the same manner as in Example b-7, except that the amount of the surfactant used in Example b-7 was 0.8 g (average particle diameter of 286 nm).

(Example b-10)

100 g of a primary emulsion dispersion was obtained in the same manner as in Example b-7 except that the amount of the surfactant used in Example b-7 was 0.7 g (average particle diameter of 290 nm).

(Example b-11)

100 g of a primary emulsion dispersion was obtained in the same manner as in Example b-7 except that the amount of the surfactant used in Example b-7 was 0.6 g (average particle diameter of 295 nm).

(Example b-12)

100 g of a primary emulsion dispersion was obtained in the same manner as in Example b-7, except that the amount of the surfactant used in Example b-7 was 0.2 g (average particle diameter of 325 nm).

(Example b-13)

100 g of a primary emulsion dispersion was obtained in the same manner as in Example b-7 except that the surfactant used in Example b-7 was changed to Surfynol 420 (manufactured by Nisshin Chemical Industry Co., Ltd.) (average particle size of 290 nm).

(Example b-14)

100 g of a primary emulsion dispersion was obtained in the same manner as in Example b-7 except that the surfactant used in Example b-7 was changed to Surfynol 440 (manufactured by Nisshin Chemical Co., Ltd.) (average particle size of 157 nm).

(Example b-15)

The same method as in Example b-7, except that the surfactant used in Example b-7 was changed to 0.1 g of Surfynol 104 (manufactured by Nisshin Chemical Industry Co., Ltd.) and 0.1 g of Surfynol 420 (manufactured by Nisshin Chemical Industry Co., Ltd.). to obtain 100 g of a primary emulsion dispersion (average particle size of 328 nm).

(Example b-16)

100 g of a primary emulsion dispersion was obtained in the same manner as in Example b-7, except that the amount of Surfynol 420 (manufactured by Nisshin Chemical Industry Co., Ltd.) used in Example b-15 was changed to 0.9 g (average particle size of 287 nm). .

(Example b-17)

The surfactant used in Example b-7 was changed to Surfynol 104 (manufactured by Nisshin Chemical Industries, Ltd.) 0.1 g, Surfynol 420 (manufactured by Nisshin Chemical Industries, Ltd.) 0.1 g and KF-354L (manufactured by Shin-Etsu Silicone Co., Ltd.) 0.8 g Except that, 100 g of a primary emulsion dispersion was obtained in the same manner as in Example b-7 (average particle size of 326 nm).

(Example b-18)

The same as in Example b-16, except that the usage-amount of Surfynol 420 (manufactured by Nisshin Chemical Industry Co., Ltd.) used in Example b-17 was changed to 0.2 g, and the usage-amount of KF-354L (made by Shin-Etsu Silicone Co., Ltd.) was changed to 0.7 g. 100 g of a primary emulsion dispersion was obtained by the method of (average particle diameter 323 nm).

(Example b-19)

The same as in Example b-16, except that the usage-amount of Surfynol 420 (manufactured by Nisshin Chemical Industry Co., Ltd.) used in Example b-17 was changed to 0.3 g, and the usage-amount of KF-354L (made by Shin-Etsu Silicone Co., Ltd.) was changed to 0.6 g. 100 g of a primary emulsion dispersion was obtained by the method of (average particle size 321 nm).

(Example b-20)

The same as in Example b-16, except that the usage-amount of Surfynol 420 (manufactured by Nisshin Chemical Industry Co., Ltd.) used in Example b-17 was changed to 0.6 g, and the usage-amount of KF-354L (made by Shin-Etsu Silicone Co., Ltd.) was changed to 0.3 g. 100 g of a primary emulsion dispersion was obtained by the method of (average particle diameter 317 nm).

(Example b-21)

100 g of a primary emulsion dispersion was obtained in the same manner as in Example b-7 except that the rotation speed of the high-speed homogenizer in Example b-7 was changed to 10,000 rpm (average particle size of 367 nm).

(Comparative Example c-1)

In Example b-1, except that the surfactant was not added, a primary emulsion dispersion was obtained in the same manner as in Example b-1 (average particle diameter of 3.81 µm).

(Comparative Example c-2)

A primary emulsion dispersion was obtained in the same manner as in Example b-1 except that the surfactant of Example b-1 was changed to Pluronic 10R5 (manufactured by Sigma-Aldrich) (average particle diameter of 2.89 µm).

(Comparative Example c-3)

A primary emulsion dispersion was obtained in the same manner as in Example b-1 except that the surfactant of Example b-1 was changed to Pluronic F108 (manufactured by Sigma-Aldrich) (average particle diameter of 2.45 µm).

(Comparative Example c-4)

A primary emulsion dispersion was obtained in the same manner as in Example b-1 except that the surfactant of Example b-1 was changed to Pluronic F127 (manufactured by Sigma-Aldrich) (average particle diameter of 2.45 µm).

(Comparative Example c-5)

A primary emulsion dispersion was obtained in the same manner as in Example b-1 except that the surfactant of Example b-1 was changed to PEG E400 (manufactured by Sigma-Aldrich) (average particle diameter of 2.72 µm).

(Comparative Example c-6)

In Example b-1, a primary emulsion dispersion was obtained in the same manner as in Example b-1, except for stirring at 800 rpm with a magnetic stirrer instead of a high-speed homogenizer (average particle size of 31.83 µm). The obtained emulsion dispersion liquid was left still at room temperature for 1 day, and liquid crystal settled.

In Examples b-1 to b-6 and Comparative Examples c-1 to c-6, except for Comparative Example c-6, no layer separation or sedimentation was observed even after 1 day of standing.

As shown in Examples b-1 to b-6 and Comparative Examples c-1 to c-5, by appropriately selecting the type of surfactant, not a micro-sized emulsion but a nano-sized emulsion can be produced.

Further, by changing the contents of distilled water, PVA, surfactant, and liquid crystal, which are constituent components of the primary emulsion dispersion, changing the type of surfactant, or changing the dispersion conditions of the homogenizer, Examples b-7 to b Although primary emulsion dispersions of -21 were prepared, also in Examples b-7 to b-21, layer separation or sedimentation was not particularly observed, and it was confirmed that a good emulsion having a nano size could be produced.

[Preparation of secondary emulsion dispersion]

(Example d-1)

The primary emulsion dispersion obtained in Example b-1 was treated 5 times at a pressure of 23,000 psi with a high-pressure homogenizer (Microfluidizer M110: manufactured by PS Japan) to refine it, and the secondary emulsion having an average particle size of the emulsion of 138 nm 100 g of dispersion was obtained.

(Examples d-2 to d-4)

100 g of the secondary emulsion dispersion was prepared in the same manner as in Example d-1, except that the primary emulsion dispersion of Example d-1 was changed to the primary emulsion dispersion obtained in Examples b-2 to b-4, respectively. obtained (each average particle diameter was 110 nm for Example d-2, 128 nm for Example d-3, and 135 nm for Example d-4).

(Examples d-7 to d-21)

100 g of the secondary emulsion dispersion was prepared in the same manner as in Example d-1, except that the primary emulsion dispersion of Example d-1 was changed to the primary emulsion dispersion obtained in Examples b-7 to b-21, respectively. (Each average particle diameter is 116 nm for Example d-7, 118 nm for Example d-8, 119 nm for Example d-9, 125 nm for Example d-10, 130 nm for Example d-11, Example d-12 is 145 nm, Example d-13 is 127 nm, Example d-14 is 106 nm, Example d-15 is 148 nm, Example d-16 is 121 nm, Example d-17 is 145 nm, Example d- 18 was 141 nm, Example d-19 was 138 nm, Example d-20 was 136 nm, and Example d-21 was 118 nm).

(Example d-7-1)

100 g of a secondary emulsion dispersion was obtained in the same manner as in Example d-7 except that the treatment pressure of the high-pressure homogenizer in Example d-7 was changed to 20,000 psi (average particle diameter of 121 nm).

(Example d-7-2)

100 g of a secondary emulsion dispersion was obtained in the same manner as in Example d-7 except that the treatment pressure of the high-pressure homogenizer in Example d-7 was changed to 15,000 psi (average particle diameter of 145 nm).

(Example d-7-3)

100 g of a secondary emulsion dispersion was obtained in the same manner as in Example d-7 except that the treatment pressure of the high-pressure homogenizer in Example d-7 was changed to 10,000 psi (average particle diameter of 213 nm).

(Example d-7-4)

100 g of a secondary emulsion dispersion was obtained in the same manner as in Example d-7 except that the treatment pressure of the high-pressure homogenizer in Example d-7 was changed to 5,000 psi (average particle diameter of 276 nm).

[Production of liquid crystal nanocapsule dispersion]

(Example 1)

100 g of the secondary emulsion dispersion prepared in Example d-1 was added to a 50 mL eggplant-type flask equipped with a stirrer, stirred at 40° C. for 24 hours, 70 rpm for coacervation, and then 1 mass % hydrochloric acid was added. The solution was adjusted to pH 3, 0.8 g (5.4 mmol) of a dialdehyde compound (39 mass% glyoxal aqueous solution: manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added, stirred at 40° C. for 12 hours, and 70 rpm to obtain a liquid crystal nanocapsule dispersion. got it

The hydrochloric acid used was prepared by diluting 35 mass % hydrochloric acid manufactured by Tokyo Kasei Kogyo Co., Ltd.

About 100 g of liquid crystal nanocapsule dispersion was concentrated (40 Torr, 40° C., 100 rpm) to 50 g with an evaporator to obtain 50 g of liquid crystal nanocapsule dispersion (average particle size of liquid crystal nanocapsules 138 nm).

(Example 2) to (Example 4)

50 g of liquid crystal nanocapsule dispersions were obtained in the same manner as in Example 1 except that the secondary emulsion dispersion used in Example 1 was changed to the secondary emulsion dispersion obtained in Examples d-2 to d-4, respectively (each The average particle diameter was 113 nm in Example 2, 129 nm in Example 3, and 136 nm in Example 4).

(Example 5)

50 g of liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 1 except that the liquid crystal used in Example 1 was changed to DLS-89001 (manufactured by Daxin Material) (average particle diameter of 137 nm).

(Comparative Example 1)

50 g of liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 1 except that the aqueous glyoxal solution of Example 1 was changed to 0.44 g (5.4 mmol) of a 37 mass% aqueous formaldehyde solution (manufactured by Junsei Chemical Co., Ltd.) (average particle size) 132 nm).

(Comparative Example 2)

The same method as in Example 1 was used except that the aqueous glyoxal solution of (Example 1) was changed to 1.1 g (5.4 mmol) of a 50 mass% aqueous glutaraldehyde solution (manufactured by Sigma-Aldrich), and a precipitate was formed. , a dispersion-stable liquid crystal nanocapsule dispersion could not be obtained.

(Comparative Example 3)

In Comparative Example 2, 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Comparative Example 2, except that hydrochloric acid was not added. When the obtained liquid crystal nanocapsule dispersion was left at room temperature for 1 week, a precipitate was formed, and a dispersion stable liquid crystal nanocapsule dispersion could not be obtained.

(Comparative Example 4)

As a result of preparation in the same manner as in Comparative Example 2, except that the amount of PVA used in Comparative Example 2 was 0.3 g, a precipitate was formed, and a dispersion-stable liquid crystal nanocapsule dispersion could not be obtained.

(Comparative Example 5)

In Comparative Example 2, 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Comparative Example 2, except that the stirring conditions after adding the glutaraldehyde aqueous solution were changed to “5° C., 12 hours, 70 rpm”. The obtained liquid crystal nanocapsule dispersion liquid was left to stand at room temperature for 2 days, and gelatinized.

(Comparative Example 6)

In Example 1, the glyoxal aqueous solution was changed to 0.22 g (2.7 mmol) of a 37 mass % aqueous formaldehyde solution (manufactured by Junsei Chemical Co., Ltd.) and 1.1 g (2.7 mmol) of a 50 mass % aqueous solution of glutaraldehyde (manufactured by Sigma-Aldrich). As a result of preparation in the same manner as in Example 1, except for the above, a precipitate was formed, and a dispersion-stable liquid crystal nanocapsule dispersion could not be obtained.

(Comparative Example 7)

The same method as in Example 1 was used except that the glyoxal aqueous solution of Example 1 was changed to propionaldehyde (manufactured by Tokyo Kasei Kogyo Co., Ltd.) to 0.31 g (5.4 mmol) of propionaldehyde. could not get

In the preparation of liquid crystal nanocapsule dispersions, when crosslinking PVA, an aldehyde compound having a large number of carbon atoms (for example, a dialdehyde compound such as glutaraldehyde having an alkylene chain or a monoaldehyde compound such as propionaldehyde) is used as a crosslinking agent When used, as shown in Comparative Examples 2 to 7, aggregates and precipitates were formed, and it was found that it was difficult to obtain liquid crystal nanocapsule dispersions having good dispersibility and dispersion stability. In addition, as shown in Comparative Examples 3 to 5, when liquid crystal nanocapsules are produced using a glutaraldehyde crosslinking agent, obtaining a liquid crystal nanocapsule dispersion having good dispersibility and dispersion stability is difficult regardless of the production conditions. I knew it was difficult. That is, from the results of Comparative Examples 2 and 3, it was found that, when glutaraldehyde was used as a crosslinking agent, dispersion-stable liquid crystal nanocapsules could not be obtained even when the conditions of acid addition were changed. From the results of Comparative Example 2 and Comparative Example 4, it was found that dispersion-stable liquid crystal nanocapsules could not be obtained even when the amount of PVA was changed. From the results of Comparative Example 2 and Comparative Example 5, it was found that dispersion-stable liquid crystal nanocapsules could not be obtained even when the temperature conditions were changed.

On the other hand, in the preparation of liquid crystal nanocapsule dispersions, when an aldehyde compound having a small carbon number (for example, formaldehyde or glyoxal, etc.) is used as a crosslinking agent when the PVA is crosslinked, Examples 1 to 5 and Comparative Example 1 As shown in, it was possible to prepare a liquid crystal nanocapsule dispersion having good dispersibility and dispersion stability.

However, when formaldehyde is used as a crosslinking agent, good results are obtained in the liquid crystal nanocapsule dispersion as shown in Comparative Example 1 above. As described in the <Cross-sectional image evaluation by SEM of a liquid crystal display layer> to do, a favorable nano-PDLC structure was not shown. The cross-sectional image evaluation by SEM will be described in detail below.

[Production of liquid crystal display element]

(Example 1-DE)

<IPS board>

The IPS substrate is a size of 30 mm × 35 mm washed with pure water and IPA (isopropyl alcohol), and is an alkali-free glass substrate having a thickness of 0.7 mm.

An ITO (Indium-Tin-Oxide) electrode having a comb pattern having an electrode width of 10 μm and an electrode-electrode spacing of 10 μm is formed on the substrate to form a pixel. The size of the pixel is 10 mm in both the horizontal and vertical directions.

<Formation of liquid crystal display layer>

The liquid crystal nanocapsule dispersion prepared in Example 1 was applied to the electrode-forming surface of the IPS substrate by a bar coater method using OSP-18 (manufactured by OSG System Products), and at room temperature (about 25° C.) for 15 minutes. After drying, the liquid crystal display element provided with the liquid crystal display layer which has a liquid crystal nanocapsule was produced by baking in 70 degreeC hot-air circulation oven for 1 hour.

An example of a liquid crystal display device having a liquid crystal display layer formed using the liquid crystal nanocapsule dispersion of Example 1 is referred to as Example 1-DE.

(Example 1-DE-1)

In Example 1-DE, except having changed the bar used at the time of apply|coating into OSP-52 (made by OSG System Products), it carried out similarly to Example 1-DE, and produced the liquid crystal display element.

(Example 2-DE) to (Example 5-DE)

In Example 1-DE, except having changed the liquid crystal nanocapsule dispersion liquid into Examples 2-5, it carried out similarly to Example 1-DE, and produced the liquid crystal display element.

Examples of liquid crystal display devices formed using the liquid crystal nanocapsule dispersions of Examples 2 to 5 are referred to as Examples 2-DE to 5-DE, respectively.

(Comparative Example 1-DE) to (Comparative Example 7-DE)

In Example 1-DE, except having changed the liquid crystal nanocapsule dispersion liquid into Comparative Examples 1-7, it carried out similarly to Example 1-DE, and produced the liquid crystal display element.

Examples of liquid crystal display devices formed using the liquid crystal nanocapsule dispersions of Comparative Examples 1 to 7 are referred to as Comparative Examples 1-DE to 7-DE, respectively.

[Evaluation of liquid crystal display element]

<Evaluation of cross-sectional image by SEM (scanning electron microscope) of liquid crystal display layer>

In Examples 1-DE to 5-DE and Comparative Example 1-DE and Comparative Example 3-DE, the cross section of the liquid crystal display layer was observed by SEM (JSM-7400F: manufactured by JEI Corporation).

In Examples 1-DE to 5-DE, formation of a nano PDLC (polymer dispersed liquid crystal) structure was confirmed, but in Comparative Example 1-DE and Comparative Example 3-DE, formation of a nano PDLC structure was not confirmed.

A cross-sectional SEM image of Example 1-DE is shown in FIG. 7 . Moreover, the cross-sectional SEM image of Example 1-DE-1 is shown in FIG. A cross-sectional SEM image of Comparative Example 1-DE is shown in FIG. 9 .

When glyoxal is used as a crosslinking agent, liquid crystal nanocapsules having excellent shape retention properties can be produced, so that a clear nano-PDLC structure is formed as shown in FIGS. 7 and 8 . On the other hand, when formaldehyde is used as a crosslinking agent, liquid crystal nanocapsules having sufficiently satisfactory shape retention cannot be obtained. 9, a clean nano-PDLC structure cannot be formed.

<VHR (voltage retention) evaluation of liquid crystal display elements>

After applying the voltage of 4V with the application time of 60 microseconds at room temperature (about 25 degreeC) using the liquid crystal display elements of Examples 1-DE - 4-DE, the voltage retention 16.67 milliseconds after application release was measured. This value was made into voltage retention (VHR).

The results are shown in Table 1 below.

As for the VHR of the liquid crystal display elements of Examples 1-DE - 4-DE, all showed the favorable result. In addition, since the value of VHR changes depending on the type of surfactant used, in order to obtain a liquid crystal display device showing a desired VHR value, it is sufficient to select the surfactant to be used after sufficiently considering the type of surfactant.

[Production of liquid crystal display element with improved applicability]

(Example 6)

To 50 g of the liquid crystal nanocapsule dispersion of Example 1, 50 µL of an additive (BYK-347: manufactured by Big Chemie Japan) was added, followed by stirring for 12 hours to obtain about 50 g of a liquid crystal nanocapsule coating solution containing the additive (liquid crystal nanocapsule) average particle diameter 137 nm).

(Example 7) to (Example 9)

In Example 6, about 50 g of a liquid crystal nanocapsule coating solution was obtained in the same manner as in Example 6, except that the liquid crystal nanocapsule dispersion was changed to the liquid crystal nanocapsule dispersion obtained in Examples 2 to 4, respectively. As for the particle size, Example 7 was 115 nm, Example 8 was 131 nm, Example 9 was 132 nm).

(Example 10)

In Example 6, about 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 µL of BYK-345 (manufactured by Big Chemie Japan) (average particle size of 126 nm).

(Example 11)

In Example 6, about 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 µL of Dynol 960 (manufactured by Nisshin Chemical Industry Co., Ltd.) (average particle size of 144 nm).

(Example 12)

In Example 6, about 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 µL of Dynol 980 (manufactured by Nisshin Chemical Industry Co., Ltd. (average particle diameter of 125 nm).

(Example 13)

In Example 6, about 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 µL of KF-6011 (manufactured by Nisshin Chemical Co., Ltd.) (average particle size of 126 nm).

(Example 14)

In Example 6, about 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive amount was changed to 25 µL (average particle diameter of 137 nm).

(Example 15)

In Example 6, about 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 µL of Dynol 604 (manufactured by Nisshin Chemical Industry Co., Ltd. (average particle diameter of 125 nm).

(Example 16)

In Example 6, about 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 µL of Dynol 607 (manufactured by Nisshin Chemical Industry Co., Ltd.) (average particle size: 128 nm).

(Example 17)

In Example 6, about 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 µL of ethylene glycol (manufactured by Tokyo Kasei Kogyo Co., Ltd.) (average particle size of 123 nm).

(Example 18)

In Example 6, about 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 µL of OLFINE E1010 (manufactured by Nisshin Chemical Industry Co., Ltd.) (average particle size of 125 nm).

(Example 19)

In Example 6, about 50 g of liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 µL of Pluronic 10R5 (manufactured by Sigma-Aldrich) (average particle size of 125 nm).

(Example 20)

In Example 6, about 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 mg of Pluronic F108 (manufactured by Sigma-Aldrich) (average particle size of 125 nm).

(Example 21)

In Example 6, about 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 mg of Pluronic F127 (manufactured by Sigma-Aldrich) (average particle size of 123 nm).

(Example 22)

In Example 6, about 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 mg of Surfynol 104 (manufactured by Nisshin Chemical Industry Co., Ltd.) (average particle size of 125 nm).

(Example 23)

In Example 6, about 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 µL of Surfynol 420 (manufactured by Nisshin Chemical Co., Ltd.) (average particle size of 125 nm).

(Example 24)

In Example 6, about 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 µL of Surfynol 440 (manufactured by Nisshin Chemical Industry Co., Ltd.) (average particle size of 125 nm).

(Example 25)

In Example 6, about 50 g of a liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 µL of Surfynol SE-F (manufactured by Nisshin Chemical Co., Ltd.) (average particle size of 125 nm).

(Example 26)

In Example 6, about 50 g of liquid crystal nanocapsule dispersion was obtained in the same manner as in Example 6 except that the additive was changed to 50 µL of KF-354L (manufactured by Shin-Etsu Silicone Co., Ltd.) (average particle size of 125 nm).

(Example 6-DE) to (Example 26-DE)

In Example 1-DE, except having changed the liquid crystal nanocapsule dispersion liquid into Examples 6-26, it carried out similarly to Example 1-DE, and produced the liquid crystal display element.

Examples of liquid crystal display devices formed using the liquid crystal nanocapsule dispersions of Examples 6 to 26 are referred to as Examples 6-DE to 26-DE, respectively.

[Evaluation of liquid crystal display elements according to the presence or absence of additives]

<Evaluation of coating unevenness of liquid crystal display layer>

The coating unevenness of the liquid crystal display layer in the liquid crystal display elements of Examples 1-DE to 4-DE, Examples 6-DE to 14-DE, and Examples 15-DE to 26-DE was confirmed.

As a result, it has confirmed that all of the liquid crystal display elements of all Examples can form the favorable liquid crystal display layer of the level usable as a drive element.

However, in the liquid crystal display elements of Examples 1-DE to 4-DE and Examples 15-DE to 25-DE, small coating unevenness occurs in some places in the liquid crystal display layer, but Examples 6-DE to 14-DE and Examples 6-DE to 14-DE In the liquid crystal display element of Example 26-DE, application|coating nonuniformity was not seen in the liquid crystal display layer.

In the liquid crystal display elements of Examples 6-DE to 14-DE and Example 26-DE, a liquid crystal nanocapsule dispersion having good applicability can be obtained, so it is considered that a good liquid crystal display layer without coating unevenness is formed. Among the liquid crystal display elements of Examples, the liquid crystal display elements of Examples 6-DE to 14-DE and Example 26-DE obtained a liquid crystal display layer without coating unevenness, and became a more excellent display element.

In the liquid crystal display device of Examples 15-DE to 25-DE, an additive having no siloxane structure in the liquid crystal nanocapsule dispersion (for example, Dynol 604, Dynol 607, ethylene glycol, OLFINE E1010, Pluronic 10R5, Pluronic F108, Pluronic) F127, Surfynol 104, Surfynol 420, Surfynol 440, Surfynol SE-F, etc.) were added.

On the other hand, in the liquid crystal display devices of Examples 6-DE to 14-DE and Example 26-DE, an additive having a siloxane structure in the liquid crystal nanocapsule dispersion (for example, BYK-345, BYK-347, Dynol 960, Dynol 980, KF-6011, KF-354L, etc.) were added.

From this, it turned out that it is effective to add the additive which has a siloxane structure to a liquid crystal nanocapsule dispersion liquid to eliminate the coating unevenness in a liquid crystal display layer and to produce the liquid crystal display element which has favorable liquid crystal nanocapsule.

<Measurement evaluation of V-T curve and contrast of liquid crystal display element>

The V-T curve and contrast in the liquid crystal display elements of Examples 1-DE to 4-DE, Examples 6-DE to 14-DE, and Examples 15-DE to 26-DE were confirmed.

For each liquid crystal display element, a white LED backlight and a luminance meter were set so that the optical axis coincided, and a liquid crystal display element with a polarizing plate was set so that the luminance was greatest when a voltage of 50 V was applied in between. Next, the V-T curve was measured by applying a voltage from 0V to 100V and measuring the luminance at the voltage. The said IPS board|substrate on which the liquid crystal capsule layer was not formed was set, the transmittance|permeability of the transmitted light measured by the cross nicol of 0%, and the transmitted light measured by parallel nicol was set to 100% of the transmittance|permeability.

As a result, it was confirmed that all of the liquid crystal display elements of all Examples exhibited favorable V-T curves and contrasts at levels usable as driving elements.

However, in the liquid crystal display elements of Examples 1-DE to 4-DE and Examples 15-DE to 25-DE, the white luminance was rather low, possibly due to uneven coating of the liquid crystal display layer, but Example 6-DE The liquid crystal display elements of -14-DE and Example 26-DE showed very excellent white luminance.

The measurement result of the V-T curve of Example 1-DE is shown in FIG. Moreover, the measurement result of the V-T curve of Example 6-DE is shown in FIG.

As is clear from the comparison results between the examples (Example 1-DE, etc.) and the comparative examples (Comparative Example 1-DE, Comparative Example 2-DE, Comparative Example 7-DE, etc.), liquid crystal nano As a capsule, in a liquid crystal nanocapsule dispersion (coating liquid for a liquid crystal display layer) containing liquid crystal nanocapsules, to produce liquid crystal nanocapsules that can improve dispersibility and dispersion stability of liquid crystal nanocapsules, when crosslinking PVA It was found that it is necessary to use glyoxal, not formaldehyde, glutaraldehyde, or propionaldehyde, as a crosslinking agent.

Further, as is clear from the results of Examples 1-DE to 26-DE, a liquid crystal obtained by forming a liquid crystal nanocapsule dispersion containing liquid crystal nanocapsules of the present invention comprising a PVA resin crosslinked using glyoxal as a crosslinking agent. It was confirmed that the display layer exhibited a clear nano-PDLC structure. And the liquid crystal display element which has liquid crystal nanocapsule of this invention showed a favorable V-T curve and contrast, and it has confirmed becoming a favorable display element of the level which can be used as a drive element.

[Production of a liquid crystal display device having a liquid crystal display layer produced without going through the step of adjusting the solution amount of the liquid crystal nanocapsule dispersion]

(Example 27)

In a 50 mL eggplant-type flask equipped with a stirring device, 50 g of the secondary emulsion dispersion obtained in Example d-7 was used, and 50 g of the secondary emulsion dispersion was stirred at 40° C., 24 hours, and 70 rpm for coacervation. After that, 1 mass % hydrochloric acid is added to adjust the pH to 3, 0.8 g (5.4 mmol) of a dialdehyde compound (39 mass % glyoxal aqueous solution: manufactured by Tokyo Kasei Kogyo Co., Ltd.) is added, 40° C., 12 hours, 70 rpm was stirred to obtain a liquid crystal nanocapsule dispersion (average particle diameter of liquid crystal nanocapsules 115 nm).

The hydrochloric acid used was prepared by diluting 35 mass % hydrochloric acid by Tokyo Kasei Kogyo Co., Ltd.

(Example 28) to (Example 31)

The liquid crystal nanocapsule dispersion was prepared in the same manner as in Example 27, except that the secondary emulsion dispersion used in Example 27 was changed to the secondary emulsion dispersion obtained in Examples d-7-1 to d-7-4, respectively. (The average particle diameter of Example 28 was 120 nm, Example 29 was 144 nm, Example 30 was 211 nm, Example 31 was 274 nm, respectively).

(Example 32) to (Example 38)

Liquid crystal nanocapsule dispersions were obtained in the same manner as in Example 27, except that the secondary emulsion dispersion used in Example 27 was changed to the secondary emulsion dispersion obtained in Examples d-8 to d-14, respectively (each average As for the particle size, Example 32 was 117 nm, Example 33 was 119 nm, Example 34 was 124 nm, Example 35 was 128 nm, Example 36 was 144 nm, Example 37 was 126 nm, Example 38 was 105 nm).

(Example 27-DE) to (Example 38-DE)

In Example 1-DE, except having changed the liquid crystal nanocapsule dispersion liquid into Examples 27-38, it carried out similarly to Example 1-DE, and produced the liquid crystal display element.

Liquid crystal display devices such as Example 1-DE were manufactured through a concentration step, which is a step of adjusting the solution amount of the liquid crystal nanocapsule dispersion, whereas the liquid crystal display devices of Examples 27-DE to 38-DE were concentrated through the concentration step. Manufactured without going through

Examples of liquid crystal display devices formed using the liquid crystal nanocapsule dispersions of Examples 27 to 38 are referred to as Examples 27-DE to 38-DE, respectively.

[Evaluation of liquid crystal display elements according to the presence or absence of a process for adjusting the amount of liquid crystal nanocapsule dispersion]

<Evaluation of coating unevenness of liquid crystal display layer>

The coating unevenness of the liquid crystal display layer in the liquid crystal display element of Examples 27-DE-38-DE was confirmed.

As a result, it has been confirmed that, in all of the liquid crystal display elements of all these examples, a good liquid crystal display layer having a level usable as a driving element can be formed.

However, in the liquid crystal display element of Example 36-DE or Example 38-DE, small coating unevenness occurs in some places in the liquid crystal display layer, but the liquid crystal display element of Examples 27-DE to 35-DE and Example 37-DE In this case, the coating unevenness was not seen in the liquid crystal display layer.

In the liquid crystal display elements of Examples 27-DE to 35-DE and Example 37-DE, a liquid crystal nanocapsule dispersion having good applicability can be obtained, so it is considered that a good liquid crystal display layer without coating unevenness is formed. Among the liquid crystal display elements of Examples, the liquid crystal display elements of Examples 27-DE to 35-DE and Example 37-DE obtained a liquid crystal display layer without coating unevenness, and became a more excellent display element.

In Example 36-DE, since the addition amount of the surfactant (Surfynol 104) was small, it is thought that the applicability|paintability was inferior compared with the other Example.

Moreover, since Example 38-DE used the surfactant of Surfynol 440, it is thought that the applicability|paintability worsened compared with the other Example.

Therefore, as shown in Examples 27-DE to 38-DE, a liquid crystal display layer free from coating unevenness can be produced by appropriately selecting the type and amount of surfactant added.

Further, in Examples 27-DE to 35-DE and Example 37-DE, an additive having a siloxane structure was not added, but coating unevenness was not observed. In these Examples, a concentration step of adjusting the solution amount of the liquid crystal nanocapsule dispersion is not performed, but in a liquid crystal display device manufactured without such a concentration step, if the type and amount of surfactant are appropriately selected, the siloxane structure Even if it did not add the additive which has, it turned out that the liquid crystal display element which shows favorable applicability|paintability can be obtained.

<Measurement evaluation of V-T curve and contrast of liquid crystal display element>

The V-T curve and contrast in the liquid crystal display element of Examples 27-DE-38-DE were confirmed.

For each liquid crystal display element of Examples 27-DE to 38-DE, a white LED backlight and a luminance meter were set so that the optical axes coincided, and a polarizing plate was attached therebetween so that the luminance was greatest when a voltage of 50 V was applied. One liquid crystal display element was set. Next, the V-T curve was measured by applying a voltage from 0V to 100V and measuring the luminance at the voltage. The said IPS board|substrate on which the liquid crystal capsule layer was not formed was set, the transmittance|permeability of the transmitted light measured by the cross nicol of 0%, and the transmitted light measured by parallel nicol was set to 100%.

As a result, it was confirmed that all of the liquid crystal display elements of Examples 27-DE to 38-DE exhibited favorable V-T curves and contrasts at levels usable as driving elements.

However, in the liquid crystal display elements of Examples 36-DE and Example 38-DE, the white luminance was rather low, possibly due to uneven coating of the liquid crystal display layer, but Examples 27-DE to 35-DE and Example 37 In the liquid crystal display element of -DE, the very outstanding white luminance was shown.

Among them, in the liquid crystal display elements of Examples 27-DE to 30-DE, Examples 32-DE to 35-DE, and Example 37-DE, Examples 6-DE to 14-DE to which an additive having a siloxane structure was added And compared with Example 26-DE, black luminance was low, and showed favorable contrast.

The measurement result of the V-T curve of Example 27-DE is shown in FIG.

In addition, in Examples 27-DE to 30-DE, Examples 32-DE to 35-DE, and Example 37-DE, an additive having a siloxane structure was further added to the liquid crystal nanocapsule dispersion, so that the applicability was further improved. I knew it could be improved.

As is clear from the comparison results between the above examples (Example 27-DE, Example 37-DE, etc.) and the above Example (Example 38-DE), by using an appropriate surfactant, good coatability and whiteness were obtained. can do it

In addition, as is clear from the comparison results between the above examples (Example 27-DE, Examples 32-DE to 35-DE) and the above Example (Example 36-DE), good coatability and good whiteness are shown. It was found that a certain amount of surfactant was required to prepare a liquid crystal nanocapsule dispersion.

In addition, as is clear from the comparison results between Examples 27-DE to 30-DE and Example 31-DE, if the pressure during the high-pressure homogenizer treatment in the secondary emulsion preparation is high, that is, liquid crystal nano When the particle diameter of the capsule dispersion liquid is small, black luminance becomes low and contrast becomes favorable.

ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal display layer which shows a clear nano PDLC structure can be formed, and the liquid crystal display element which has a liquid crystal nanocapsule which shows a favorable V-T curve and contrast can be produced.

Since the liquid crystal display element having liquid crystal nanocapsules is encapsulated in liquid crystal, it is resistant to changes in external stress such as bending, and since an alignment film is also unnecessary, the panel manufacturing process can be simplified.

Accordingly, the liquid crystal display device having the liquid crystal nanocapsule of the present invention is expected to be applied to a flexible liquid crystal display (LCD) further in the future.

1: liquid crystal nanocapsule 2: liquid crystal composition
3: Surfactant membrane 4: Polymer wall
10: mixed solution 11: emulsion dispersoid (emulsion)
12: emulsion dispersion 13: polyvinyl alcohol (PVA)
14: polymer wall 15: liquid crystal nanocapsule
16: liquid crystal nanocapsule dispersion 17: liquid crystal nanocapsule dispersion containing additives
20: liquid crystal display element 21: support substrate
22: liquid crystal nanocapsule 23: liquid crystal display layer
24: electrode
a: polyvinyl alcohol (PVA) b: surfactant
c: liquid crystal composition d: glyoxal
e: hydrochloric acid f: additive

Claims (14)

A liquid crystal nanocapsule covering a liquid crystal composition with a polymer wall, wherein the polymer wall is made of a polyvinyl alcohol (PVA) resin crosslinked with glyoxal, and the liquid crystal nanocapsule has an average particle diameter of 10-355 nm. The method of claim 1,
The average particle diameter is 50 ~ 200nm, liquid crystal nanocapsules. A method for producing liquid crystal nanocapsules having an average particle diameter of 10-355 nm,
A step of preparing a mixed solution obtained by mixing a liquid crystal composition, a surfactant, and a mixed material containing polyvinyl alcohol (PVA) in a solvent;
A step of preparing an emulsion from the mixed solution,
disposing the polyvinyl alcohol (PVA) around the emulsion dispersoid using a coacervation method, and
Using glyoxal, polyvinyl alcohol (PVA) is cross-linked to form a polymer wall surrounding the liquid crystal composition, and the liquid crystal nanocapsule comprising the step of manufacturing a liquid crystal nanocapsule encapsulating the liquid crystal composition in the polymer wall. manufacturing method. 4. The method of claim 3,
The step of preparing the emulsion includes a first preparing step of preparing an emulsion using a first dispersive emulsifying device, and an agent for preparing an emulsion having a smaller particle size than the particle size obtained in the first preparing step using a second dispersing emulsifying device 2 A method for producing a liquid crystal nanocapsule comprising a preparation step. 5. The method according to claim 3 or 4,
A method for producing liquid crystal nanocapsules, wherein the step of disposing the polyvinyl alcohol (PVA) around the emulsion dispersoid using the coacervation method is performed at a temperature near the cloud point of the polyvinyl alcohol (PVA). 6. The method according to any one of claims 3 to 5,
A method for producing a liquid crystal nanocapsule, wherein the crosslinking reaction is performed in an acidic solution. A liquid crystal nanocapsule dispersion in which the liquid crystal nanocapsules according to claim 1 or 2 are dispersed in a solvent. 8. The method of claim 7,
The liquid crystal nanocapsule dispersion, wherein the liquid crystal nanocapsule dispersion further contains an additive for lowering the surface tension of the liquid crystal nanocapsule dispersion. A method for preparing a liquid crystal nanocapsule dispersion in which liquid crystal nanocapsules having an average particle diameter of 10-355 nm are dispersed in a solvent,
A step of preparing a mixed solution obtained by mixing a liquid crystal composition, a surfactant, and a mixed material containing polyvinyl alcohol (PVA) in a solvent;
A step of preparing an emulsion from the mixed solution,
disposing the polyvinyl alcohol (PVA) around the emulsion dispersoid using a coacervation method, and
By using glyoxal, polyvinyl alcohol (PVA) is cross-linked to form a polymer wall surrounding the liquid crystal composition, and liquid crystal nanocapsules containing the liquid crystal composition are prepared by the polymer wall, whereby the liquid crystal nanocapsules are dissolved in the solvent. A method for producing a liquid crystal nanocapsule dispersion, comprising the step of preparing a dispersed liquid crystal nanocapsule dispersion. 10. The method of claim 9,
With respect to the liquid crystal nanocapsule dispersion, the method for producing a liquid crystal nanocapsule dispersion, further comprising the step of adding an additive for lowering the surface tension of the liquid crystal nanocapsule dispersion. 11. The method according to claim 9 or 10,
With respect to the liquid crystal nanocapsule dispersion, the method for producing a liquid crystal nanocapsule dispersion further comprising the step of adjusting the solution amount of the liquid crystal nanocapsule dispersion. A liquid crystal display device comprising: a substrate; an electrode formed on the substrate; the liquid crystal nanocapsule according to claim 1 or 2; and an electric field applying means for applying an electric field to the liquid crystal nanocapsule via an electrode. A substrate, an electrode formed on the substrate, a liquid crystal display layer formed by applying the liquid crystal nanocapsule dispersion according to claim 7 or 8, and an electric field for applying an electric field to the liquid crystal nanocapsule in the liquid crystal display layer through an electrode A liquid crystal display element having an application means. 14. The method of claim 13,
The liquid crystal display layer has a liquid crystal nanocapsule and a polymer binder made of polyvinyl alcohol (PVA), a liquid crystal display device.

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