KR20120024996A - Polarizing material, coating material for polarizing film production containing same, and polarizing film - Google Patents

Abstract

The present invention provides a polarizing material having good heat resistance instead of a dye, a coating material for manufacturing a polarizing film comprising the same, and a polarizing film. The present invention specifically includes a polarizing material made of metal plated nanowires obtained by forming a metal plating layer having a thickness of 1 to 15 nm on the surface of a nanowire made of a dielectric having an average thickness of 20 to 300 nm and an average length of 0.4 μm or more, and the same. It provides the coating material for polarizing film manufacture, and a polarizing film.

Description

POLARIZING MATERIAL, COATING MATERIAL FOR POLARIZING FILM PRODUCTION CONTAINING SAME, AND POLARIZING FILM}

TECHNICAL FIELD This invention relates to the polarizing material useful for the use of a polarizing plate and a brightness raising polarizing plate especially, the coating material for polarizing film manufacture containing the same, and a polarizing film.

Currently, as a polarizer used near room temperature, the polarizing plate for liquid crystal displays and the polarizing plate for luminance rise (also called a luminance rising film) are put into practical use. Moreover, as a polarizer for which heat resistance is requested | required, the polarizer for optical isolators used for the purpose of noise removal at the connection interface of the optical fiber used for optical communication is put to practical use.

The said polarizing plate is obtained by orienting an anisotropic dye on a film, and is produced by extending | stretching after impregnating a water-soluble polyvinyl alcohol (PVA) film with water-soluble iodine or water-soluble dye specifically ,.

When extending | stretching the said polarizing plate for brightness rises, it is produced by extending | stretching after laminating | stacking two types of polyester films with the same refractive index in a non-stretching direction, and a different refractive index in a stretching direction alternately in 100-200 layers. This brightness raising polarizing plate reflects only polarized light having an electric field (electric field oscillating surface) in the stretching direction and reuses it to increase light utilization efficiency.

The polarizer for the optical isolator is required to have heat resistance that temporarily withstands about 260 ° C for soldering or the like. As a polarizer for light isolators, so-called lamipoles are used. Lamipol is produced by producing a film in which about 10 nm of aluminum is deposited on a silica film having a film thickness of about 1 μm, laminating it into an alternating multilayer film of silica and aluminum, and then cutting it thinly.

Patent document 1: Unexamined-Japanese-Patent No. 2008-279434 Patent Document 2: Japanese Unexamined Patent Publication No. 2006-201540 Patent document 3: Unexamined-Japanese-Patent No. 2008-83656 Patent Document 4: Japanese Patent 2005-097581

[Non-Patent Document 1] Nikkei BP, Nikkei Micro Devices, December 2005, pages 156-157. Non-Patent Document 2: Applied Optics, vol. 22, No. 16, pages 2426-2428 Non-Patent Document 3: IEEE Publishing, IEEE Journal of Quantum Electronics, Vol. 29, pp. 175-181, 1993 Non-Patent Document 4: IEEE / OSA Publication, Journal of Lightwave Technology, 15, 1042-1050 Non-Patent Literature 5: American Chemical Society Publications, Langmuir, 2004, 20, 11, 4784-4786 Non-Patent Document 6: Published by American Chemical Society, Crystal Growth and Design, 2006, Volume 6, Issue 6, pages 1504-1508 Non Patent Literature 7: Published by American Chemical Society, Crystal Growth and Design, 2006, Volume 6, Issue 11, pages 2422-2426 Non Patent Literature 8: Published by American Chemical Society, Journal of Physical Chemistry B, 2006, 110, No. 2, pages 807-811 Non-Patent Document 9: Published by American Chemical Society, Journal of the American Chemical Society, 2005, 127, 46, 16040-16041 Non-Patent Document 10: American Chemical Society Publishing, Journal of Physical Chemistry B, 2005, 109, No. 1, pages 151-154 Non-Patent Document 11: Published by American Chemical Society, Journal of Physical Chemistry B, 2006, 110, No. 2, pages 807-811 Non-Patent Document 12: American Chemical Society Publishing, ACS Nano, 2009, Vol. 3, No. 5, pages 1077-1084 Non-Patent Document 13: American, Chemical Society Publishing, Journal of Physical Chemistry C, 2008, Vol. 112, No. 5, pages 1645-1649 Non-Patent Document 14: American Chemical Society Publishing, Journal of Physical Chemistry B, 2004, No. 108, 28, pp. 9745-9751 Non-Patent Document 15: American Chemical Society Publishing, Chemistry of Materials, 2006, 18, 1634 pages Non-Patent Document 16: Published by American Chemical Society, Journal of Physical Chemistry B, 2004, Vol. 108, No. 28, pages 9745-9751 Non-Patent Document 17: American Chemical Society Publications, Journal of Physical Chemistry C, 2008, 112 (11), 4042-4048 Non-Patent Document 18: IEEE Publishing, IEEE Journal of Quantum Electronics, Vol. 29, pp. 175-181, 1993

The conventional polarizer has the following problems.

(1) Pigments, such as iodine and dye used for the conventional polarizing plate, have low heat resistance. Moreover, the stretched film of PVA used as a base material also changes dimension by wet heat, and there exists a problem that a phase difference arises and a polarization degree falls.

(2) In the conventional polarizing plate for luminance rise, the two kinds of polyester films are bonded to each other by 100 to 200 layers alternately and stretched, so uniform stretching is difficult and productivity is poor. Moreover, there exists a problem that the light transmittance of a non-stretching direction is low.

(3) The lamipole used for the polarizer for an optical isolator has a problem that workability for production and productivity are bad, and it is fragile during handling. However, the polarizer made of another material has a problem that there is no substitute material because of its low heat resistance.

These problems can be solved if there is a polarizing material having good heat resistance instead of a dye and a technique for orientating it on a substrate with good productivity.

Therefore, a main object of the present invention is to provide a polarizing material having good heat resistance instead of a dye, a coating material for producing a polarizing film and a polarizing film comprising the same.

MEANS TO SOLVE THE PROBLEM As a result of earnestly researching in order to achieve the said objective, the present inventors found out that the specific metal plating nanowire can be used as a polarizing material, it is good in heat resistance, and can be orientated on a base material with high productivity. Came to complete.

That is, this invention relates to the following polarizing material, the coating material for polarizing film manufacture, and a polarizing film.

1. Polarizing material consisting of metal plated nanowires obtained by forming a metal plating layer having a thickness of 1 to 15 nm on the surface of a nanowire made of a dielectric having an average thickness of 20 to 300 nm and an average length of 0.4 µm or more.

2. Said dielectric material is light-polarizing material of said claim | item 1 whose refractive index is 1.47-2.2.

3. The dielectric has a core layer and a coat layer formed on the surface thereof, wherein the refractive index of the core layer is 1.47 to 2.2, and the refractive index of the coat layer is within nc ± 0.4 using the refractive index of the core layer as nc. The polarizing material of 1 item.

4. The polarizing material according to item 1, wherein the metal plating layer is a plating layer of at least one metal selected from the group consisting of nickel, chromium, zinc, tantalum, niobium, silver, iron, and aluminum.

5. Paint for polarizing film manufacture containing the polarizing material of said claim | item 1.

6. The paint according to item 5, wherein the paint contains a resin, and the refractive index of the resin is within nd ± 0.4 using the refractive index of the dielectric as nd.

7. Coating material for polarizing film containing polarizing material and resin of said claim | item 3, and the refractive index of the said resin is within nc ± 0.4 using refractive index of the said core layer as nc.

8. The said coating material is a coating material of the said Item 5 containing a (meth) acrylic resin and a crosslinking agent.

9. Polarizing film obtained by drying, after coating the coating material of said claim | item 5 on the surface of a base film.

10. The coating is a coating by a bar coat method using a coating bar,

1000×L (L：금속 도금 나노 와이어의 평균 길이) 이 되는 조건하에서의 도공이며,(1) As for the said coating, the contact length P of the circumferential part of the said coating bar and the said base film is P,

It is coating under conditions to be 1000 * L (L: average length of metal plating nanowire),

W

10000×φ (φ： 금속 도금 나노 와이어의 평균 굵기) 인 상기 항 9 에 기재된 편광막.(2) As for the said coating bar, the groove | channel is equally formed at least in the area | region which the said coating bar and the said base film contact, and the width W of the said groove | channel is 50xφ

W

The polarizing film of said claim | item 9 which is 10000 * φ ((phi): average thickness of a metal plating nanowire).

11. The polarizing film of said claim | item 9 used as a polarizing plate or a polarizing plate for luminance rise.

In the metal plated nanowire of the present invention, since the dielectric having an average thickness of 20 to 300 nm and an average length of 0.4 μm or more can be produced with good linearity, the metal plated nanowire with good linearity and orientation can be produced with good productivity. can do. Further, by forming a metal plating layer having a thickness of 1 to 15 nm, a polarizing plate that transmits light in the thickness direction and absorbs light in the longitudinal direction or transmits light in the thickness direction and reflects light in the longitudinal direction (partly It can also be set as the polarizing plate for luminance rise which also includes reflection, and can be used as a polarizing material. In addition, the metal plating layer can provide a polarizing plate excellent in heat resistance or a polarizing plate for luminance rise instead of a conventional dye (means for expressing polarization).

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows the relationship between the oscillation direction of an electric field of s-polarized and p-polarized light and the longitudinal direction, width direction, and thickness direction of a metal nanowire in the case of arranging rectangular pillar-shaped metal nanowires at right angles to the traveling direction of light. Drawing.
Specifically, it is a figure which shows that s-polarized light is absorbed or reflected, p-polarized light is transmitted, and it becomes a polarizing material.
FIG. 2: is a figure which shows the advancing direction of p-polarized light passing through the resin layer 1 → metal plating layer 2 → dielectric layer 3, and its electric field. The electric field of the p-polarized light is parallel to the ground and vibrates in a direction perpendicular to the traveling direction. In this electric field, the free electrons in the plating layer move in the w-direction, and the shorter the w, the better the transmittance of the p-polarized light.
It is a figure which shows the model for simulating the polarization property of the polarizing film (an example) of this invention by a finite difference time domain method.

Hereinafter, first, the relationship between the metal nanowires and the polarization properties will be described, and then the polarizing material (metal plated nanowires), the coating material for manufacturing the polarizing film, and the polarizing film of the present invention will be described.

Metal nano With wire Polar  relation

Light can be divided into two polarizations (hereafter referred to as p-polarized light and s-polarized light) which vibrate in directions perpendicular to each other in a plane perpendicular to the advancing direction. The polarizing film has a function of transmitting one polarized light and blocking (absorbing or reflecting) the other polarized light among two polarized light.

Recently, rod-shaped metals having a width and length of nanometer size have been reported to exhibit anisotropy against electromagnetic waves such as light. In addition, although the rod-shaped metal of 1 micrometer or more in length may be called a metal nanowire, and the rod metal of less than 1 micrometer in length may be called a metal nanorod, in the following specification, the rod-shaped metal which is 0.4 micrometer or more in length is used as metal nano It is called a wire.

Hereinafter, light will be described as an example of electromagnetic waves.

Consider the case where the length of the metal nanowire is longer than the wavelength of light and the width is sufficiently smaller than the wavelength of light. When light enters the metal nanowire, the polarized light having the electric field oscillating surface in the longitudinal direction of the metal nanowire is absorbed or reflected by vibrating the free electrons of the metal nanowire. On the other hand, polarized light having an electric field oscillation plane in the width direction of the metal nanowire is transmitted (because it is precisely "scattered forward") because the free electrons of the metal nanowire are unlikely to cause resonance oscillating to light. Is simply known as being "transmitted."

The reason why the metal absorbs or reflects light is that light is an electromagnetic wave, free electrons in the metal resonate and vibrate in an electric field of light, and the energy of the light is changed into kinetic energy. Therefore, in order for a metal to absorb or reflect light, the width | variety of metal as much as the free electron in a metal can vibrate in the direction perpendicular | vertical to the advancing direction of light is required.

In Mie's theory and Rayleigh's scattering theory, it is thought that when the width of the metal is about 10 nm or less, free electrons cannot be vibrated, and light absorption or reflection does not occur and is transmitted. On the contrary, if the width of the metal is greater than or equal to the wavelength of light, it is considered to be efficiently absorbed or reflected. Therefore, in the case of a metal nanowire, when length is longer than the wavelength of light and width is about 10 nm or less, it is thought that it is a favorable polarizing material.

Next, the difference in absorption and reflection of light when the length of the metal nanowire is longer than the wavelength of light and the width is about 10 nm will be described with reference to FIG. 1. Further, light whose electric field vibrating surface coincides with the longitudinal direction of the metal nanowire is s-polarized light, and light whose electric field vibrating surface coincides with the width direction of the metal nanowire is p-polarized light. Fig. 1 shows the relationship between the oscillation direction of the electric field of s-polarized light and p-polarized light and the longitudinal direction, width direction, and thickness direction of the metal nanowire when the metal nanowires having a rectangular columnar shape are arranged at right angles to the traveling direction of light. Is shown.

p-polarized light does not vibrate free electrons of the metal nanowire when the width of the metal nanowire is about 10 nm or less. Therefore, regardless of the length and thickness of the metal nanowires, p-polarized light is transmitted without being absorbed or reflected.

s polarization vibrates the free electrons of the metal nanowires if the length of the metal nanowires is longer than the wavelength of light. At this time, even if the width is 10 nm or less, the light is absorbed or reflected. Further, whether light is absorbed or reflected is determined by the thickness of the metal nanowires.

The thickness at which the intensity of incident light is one-half (= about 1 / 7.5) of the natural logarithm is called "epidermal depth" and the epidermal depth is 1/2 power of (2 / ωμσ). Ω is the angular frequency of light, μ is the permeability of the metal, and σ is the electrical conductivity of the metal.

Therefore, in the case of a wavelength of 500 nm visible light, ωμ is 4.8 × 10 ^- Conductivity σ (S / m) of substantially constant, and the metal to ^9, is: 61 × 10 ^6, aluminum: 40 × 10 ^6, Ni: Since it is 15 * 10 <^6> and tantalum: 8 * 10 <^6> , skin depths become silver: 2.7 nm, aluminum: 3.5 nm, nickel: 4.1 nm, tantalum: 5.3 nm, respectively.

That is, when light enters into a metal with good conductivity whose electrical conductivity is about 8 * 10 <^6> S / m, light is absorbed when thickness is about 4-5 nm. If the thickness is two times or more (10 nm or more), after absorbing light from the surface, light reflection occurs because the electromagnetic field generates a current opposite to the lower layer of the metal and generates reflected light. That is, when the thickness of the metal nanowire is about 5 nm, it is absorbed, and when the thickness is about 10 nm, it is reflected. This is true even when the shape of the metal nanowire is changed from a square pillar to a polygonal pillar.

Considering the skin depth of the metal, it can be seen that when the length of the metal nanowire is 400 nm (0.4 μm) or more and the thickness is 5 nm or less, p-polarized light is transmitted and s-polarized light is absorbed. In addition, when the length is 400 nm (0.4 m) or more and the thickness is about 10 nm, it can be seen that p-polarized light is transmitted and s-polarized light is reflected. Therefore, when the metal nanowire of this size is oriented, a polarizing plate and a polarizing plate for luminance rise are obtained.

However, in order to make polarization and orientation high, the metal nanowire is required to be straight, but the manufacturing method of the metal nanowire which is good in linearity by several nm in width and high productivity is hardly known. Further, the narrower the width of the metal nanowire, the more it bends or aggregates during handling, which causes problems in production.

Therefore, in the present invention, instead of the metal nanowire, the metal-plated nanowire obtained by forming a metal plating layer having a thickness of 1 to 15 nm on the surface of the nanowire made of a dielectric having an average thickness of 20 to 300 nm and an average length of 0.4 µm or more is prepared. Used as photonic material. In this metal plated nanowire, a dielectric material having an average thickness of 20 to 300 nm and an average length of 0.4 µm or more can be produced with good linearity, so that a metal plated nanowire with good linearity and orientation can be produced with good productivity. . Further, by forming a metal plating layer having a thickness of 1 to 15 nm, a polarizing plate that transmits light in the thickness direction and absorbs light in the longitudinal direction or transmits light in the thickness direction and reflects light in the longitudinal direction (partly It can also be set as the polarizing plate for luminance rise (including reflection), and can be used as a polarizing material. In addition, the metal plating layer can replace the conventional pigment | dye (means which express polarization property), and can provide the polarizing plate excellent in heat resistance, or the polarizing plate for luminance rise.

Of the present invention Polarization  material

The polarizing material of the present invention is a metal plated nanowire obtained by forming a metal plating layer having a thickness of 1 to 15 nm on the surface of a nanowire made of a dielectric having an average thickness of 20 to 300 nm and an average length of 0.4 µm or more. .

In the present invention, a nanowire made of a dielectric having an average thickness of 20 to 300 nm and an average length of 0.4 µm or more is used. In addition, "average" is the average value of each thickness and length when 10 nanowires are arbitrarily picked out in an electron microscope image.

The average thickness of the dielectric is 20 to 300 nm, preferably 50 to 200 nm. In addition, when dielectric is a cylindrical shape or a pseudo-cylindrical shape, it is thickness = thickness, but when it is not, for example, even when it is a polygonal column shape or a polygonal twisted shape, it is set as thickness = thickness. Moreover, it is preferable that the length of one side of a polygonal pillar is short enough than the wavelength of light.

The aspect ratio of the dielectric is not limited, but 10 or more is preferable. If the length of the dielectric exceeds 20 µm, there is a fear that the linearity of the dielectric tends to be lost. Moreover, when aspect ratio is less than 10, there exists a possibility that polarization property and orientation property may fall.

As a nanowire which consists of a dielectric material, the nanowire obtained by the electro spinning method, the nanowire of (meth) acrylic resin, the nanowire of silica, etc. are synthesize | combined. Moreover, nanowires, such as alumina, are synthesize | combined as a nanowire obtained by a gas phase method. In addition, Langmuir, 2004, 20 (11), 4784? 4786 pages and Crystal Growth and Design, 2006, 6 (6), 1504? 1508 pages are nanowires obtained by the hydrothermal method, having a thickness of 30? 120 nm and the number of μm in length? 50 micrometers of hydroxyapatite or fluoroapatite nanowires (all with a refractive index of about 1.64) have been reported. Furthermore, Langmuir, 2007, 23 (19), 9850? On page 9859, a method of synthesizing boehmite nanowires (a refractive index of about 1.7) is reported.

In addition, as a nanowire made of a dielectric, a nanowire made of an oxide or hydroxide such as silicon, aluminum, or a nanowire made of phosphate, sulfate, borate, silicate, or phenyl phosphate of any metal of magnesium, aluminum, calcium, zinc and potassium Also known.

In the present invention, the dielectric index is not limited to these dielectric materials and the refractive index (nd) is 1.47? If it is 2.2 nanowire, it can use preferably. Among them, the refractive index (nd) is 1.47? 1.8 is more preferable. Among these dielectrics, (meth) acrylic resins such as methyl poly (meth) acrylate, calcium carbonate, fluoroapatite, potassium titanate, magnesium sulfate and the like can be particularly preferably used.

When a dielectric consists of crystal | crystallization, a polygonal pillar shape or a polygonal pillar is twisted normally. Therefore, if necessary, the surface of the dielectric may be coated with the same or different dielectric having the same degree of refractive index, and may be used after the cylindrical or pseudo-cylindrical nanowire having the curved surface. In this case, the nanowire after coating has an average thickness of 20? 300 nm and average length of 0.4 micrometers or more, Preferably it is set so that aspect ratio may be 10 or more.

Specifically, the dielectric has a core layer and a coat layer formed on the surface thereof, and the refractive index of the core layer is 1.47? It is preferable that it is 2.2, and the refractive index of a coat layer makes the refractive index of a core layer nc, and is within nc ± 0.4. Among these, the refractive index nc of the core layer is 1.47? 1.8 is more preferable, and it is more preferable that the refractive index of a coat layer is within nc ± 0.2.

Examples of the coating layer include those in which the same compound as the core layer is shortened and precipitated so as not to have crystallization time in the same precipitation reaction, but is not limited thereto.

As a core layer, (meth) acrylic resin, silicone resin, etc. are preferable, for example. Moreover, you may make a core layer by adding a crosslinking agent (for example, a titanium crosslinking agent and a zirconium crosslinking agent) to a (meth) acrylic resin and silicone resin as needed. By adding a crosslinking agent, the refractive index of a core layer can be adjusted, and the orientation of the polarizing material finally obtained can be raised.

Forming a coat layer with an amorphous resin such as a (meth) acrylic resin or a silicone resin on the surface of the core layer to produce a nanowire having a curved surface is described in J. Am. Chem. Soc., 2005, 127 (46), 16040? 16041 pages, Crystal Growth and Design, 2006, 6 (11), 2422? 2426 pages, J. Phys. Chem. B, 2006, 110 (2), 807? 811 pages and the like. Moreover, forming a coat layer using silica is J. Phys. Chem. B, 2005, 109 (1), 151 Page 154 and J. Phys. Chem. B, 2006, 110 (2), 807? 811 pages and the like.

It is preferable to form the metal plating layer formed on the surface of the nanowire which consists of a dielectric by electroless plating. The electroless plating metal is preferably one which is easy to precipitate in the reaction in the liquid layer, 2) which does not corrode well, and 3) which does not corrode well by forming a passivation layer or a protective layer corresponding thereto on the surface.

As a metal used for a metal plating layer, at least 1 sort (s) of nickel, chromium, zinc, tantalum, niobium, silver, iron, and aluminum is preferable. Among them, at least one of nickel, chromium, zinc, tantalum, niobium, and aluminum is more preferable from the viewpoint of securing the non-coloring property of the metal plating layer. Particularly, for aluminum plating, the precipitation by pyrolysis of cyclopentadienyl aluminum in mesitylene is performed by Chem. Mater. It is reported by 2006, 18, 1634, You may plate aluminum in this reaction liquid.

The metal plating layer has a thickness of 1? 15 nm may be sufficient, Preferably it is 1? 10 nm. When the surface of a metal plating layer is covered with a passivation film, it is preferable that the thickness of a passivation film is thinner than the thickness of a metal plating layer. Moreover, it is preferable that the thickness which combined the metal plating layer and a passivation film is 2 times or less of the thickness of a metal plating layer. In addition, when intentionally forming a passive film, it can form by heating a metal plating nanowire in a solvent, or surface-treating with an oxidizing agent.

When forming a metal plating layer of about several nm, when a thing with high affinity with a metal is used as a solvent of a plating liquid, it is known that a metal is aggregated in a solvent and it is difficult to obtain a uniform metal plating layer. This point, J. Phys. Chem. B, 2004, 108 (28), 9745? 9751, J. Phys. Chem. C, 2008, 112 (11), 4042? On page 4048, it is reported that when forming a metal plating layer on the order of several nm, it is preferable to use a solvent having a low coordination property or to react near the boiling point of the solvent. Therefore, it is preferable to select such a solvent or to treat the surface of the nanowires with a coupling agent to increase the affinity with the metal before metal plating.

In the present invention, if necessary, the surface of the metal plated nanowire may be further coated with a dielectric film of 50 nm or less. It is preferable that the refractive index is within ± 0.4 with respect to said nd, and, as for the dielectric used for a coat, it is more preferable that it is within nd ± 0.2. As a coating material, for example, an alkoxysilane and an alkoxy titanium and copolymer obtained by hydrolyzing an alkoxysilane and an alkoxy zirconium with an acid or an alkali, or an alkoxysilane and alkoxy obtained by hydrolyzing an alkoxysilane and an alkoxy zirconium with an acid or an alkali The copolymer of zirconium is mentioned. As described above, when the surface of the metal plated nanowire is further coated with a dielectric film, the refractive index of the polarizing material can be adjusted, and the orientation of the polarizing material can be further improved.

The polarizing material of this invention can be used as a polarizing plate, a polarizing plate for luminance rise, and a polarizer for an optical isolator by disperse | distributing and orienting in resin with refractive index (nr) within nd ± 0.4. As refractive index nr, less than nd +/- 0.2 is more preferable.

Content of the polarizing material at the time of disperse | distributing in resin makes the total amount of resin and a polarizing material 100 weight%, and is 10? About 70 weight% is preferable, and 30 weight%? About 50 weight% is more preferable. Moreover, in order to orientate efficiently after disperse | distributing in resin, it is preferable to uniaxially stretch after dispersion | distribution. Thereby, a polarizing film is obtained.

The optical behavior of the polarizing material of the present invention is as follows.

When the length of the polarizing material is equal to or greater than the wavelength of light, the s-polarized light is absorbed or reflected by the vibration of free electrons in the metal plating layer and is not transmitted. In p-polarized light, when the thickness of the metal plating layer is sufficiently shorter than the wavelength of light, the movement of free electrons in the metal plating layer does not occur, and the metal exhibits the same optical behavior as the dielectric, and the incident light is caused by dipole vibration of electrons bound to the molecule. Scattered. In this case, it is necessary to confirm whether the scattering is forward scattering (= transmission). Moreover, since this light is scattered similarly in the internal dielectric layer, it is also necessary to confirm this scattering direction. Hereinafter, the scattering direction is verified.

In dipole vibration caused by electrons in the molecule, light identical to incident light is elastically scattered. In the uniform layer, the light goes straight. At the interface of materials having different dielectric constants, reflected light or evanescent wave is generated when the interface is a plane sufficiently larger than the wavelength of the light. This is based on the fact that the molecular group resonates and dipoles oscillate at an interface having a length corresponding to the wavelength between the interfaces.

However, in the case of p-polarized light, since there is no length of an interface corresponding to the wavelength in the thickness direction of the metal-plated nanowires, the reflected light and the evanescent wave do not occur. Therefore, what is necessary is just to irradiate the direction of the light which permeate | transmits a metal plating nanowire about p-polarized light.

Hereinafter, the polarizing material (metal plated nanowire) of this invention is disperse | distributed or oriented in resin, and it is considered that a polarizing material consists of a dielectric layer (one layer of dielectric) and a metal plating layer, and the direction of scattering = wavefront normal The direction (representing a unit vector by s) is confirmed by FIG.

In FIG. 2, light proceeds in the order of the resin layer 1 → boundary a → metal plating layer 2 → boundary b → dielectric layer 3, and the magnetic field in the resin layer 1 is H ₁ , and the speed of light is v _1. The refractive index n ₁ , the unit vector of wavefront normals s ₁ , the magnetic field in the metal plating layer 2 H ₂ , the speed of light v ₂ , the refractive index n ₂ , the unit vector of wavefront normals s ₂ , the dielectric layer (3) The internal magnetic field is H ₃ , the speed of light is v ₃ , the refractive index is n ₃ , the unit vector of the wavefront normal is s ₃ , the time is t, the position vector of boundary a is r _a , and the position vector of boundary b is r _b . At this time, the magnetic field H ₁ in the resin layer 1 at the boundary a and the magnetic field H ₂ in the metal plating layer ₂ are respectively.

H ₁ = H ₀₁ expiω (tr _a ? S ₁ / v ₁ ) and

H ₂ = H ₀₂ expiω (tr _a ? S ₂ / v ₂ ).

Since the tangent and normal components of the magnetic field component at the boundary a are continuous,

s ₁ / v ₁ = s ₂ / v ₂ , for this purpose s _1x / v ₁ = s _2x / v ₂ ,

from v ₁ n ₁ = v ₂ n ₂ , s _1x / s _2x = sinθ ₁ / sinθ ₂

n ₁ sinθ ₁ = n ₂ sinθ ₂ , the amplitude remains the same, and the advancing direction is refracted in the same manner as Snell's law.

Similarly at boundary b, the amplitude does not change,

n ₃ sinθ ₃ = n ₂ sinθ ₂ = n ₁ sinθ ₁ .

When n ₃ = n ₁ , θ ₃ = θ ₁ , and the light incident on the metal-plated nanowires does not change the intensity of light or the traveling direction of the light before and after the metal plating layer 2. Similarly, the light intensity, intensity, and advancing direction of the dielectric layer 3 → metal plating layer 2 → resin layer 1 are not changed. Thus, p-polarized light is transmitted through the metal plated nanowires while maintaining the advancing direction. This is based on the fact that forward scattering is occurring because no reflection occurs.

In addition, when the passivation film of several nm with low light absorption is in the surface of a metal plating layer, it can be considered that the thickness of a film is constant. When the refractive indexes of the resin layer and the dielectric layer are the same, the amplitude and propagation direction of the light are not changed similarly, and the p-polarized light is transmitted. In short, s-polarized light is absorbed or reflected and p-polarized light is transmitted.

In addition, in order to make a polarization degree high, the width | variety w of the vibration direction of p-polarization is so preferable in FIG. From page 157 and the like, w is preferably 100 nm or less. Among these, considering that the metal plating layer is thin and the side surfaces of the nanowires face all directions, the thickness of the nanowires is 200 nm or less and the average value of w is sufficiently shorter than 100 nm to achieve the polarization degree required as the polarizing film. It is thought to be.

Polarizer  Manufacturing paints and Polarizer

The coating material for polarizing film manufacture containing the said polarizing material is contained in this invention. The coating material for polarizing film manufacture contains the said polarizing material, and contains at least 1 sort (s) of a resin binder, a solvent, etc. in order to use as a coating material.

As a method for orientating the metal nanowires with good productivity, Japanese Patent Laid-Open No. 2008-279434 discloses an orientation coating method of metal nanowires. In the present invention, a coating material is coated using this coating method and a polarizing material is used. It is preferable to orient on a substrate.

The said coating method coats the coating material containing a polarizing material with a coating bar, and in order to orientate a polarizing material, it is necessary that the brown motion of the polarizing material in coating is gentle. Here, the Brownian motion is heavy the polarizing material, the longer the gentler.

The polarizing material of this invention is small both in size and specific gravity. Therefore, in order to align efficiently, it is preferable to set it as the coating material of the viscosity of at least several hundred mPa * s or more which melt | dissolved the resin for thickening in order to suppress Brownian motion. In this case, thickening resin turns into a resin layer which encloses a polarizing material in a coating film after coating film drying. As for the refractive index of this resin layer, in order to make the transmittance | permeability of p-polarized light favorable, it is preferable that the difference with the refractive index nd of a nanowire is within ± 0.4, and it is more preferable that it is within ± 0.2. Refractive index of a resin layer is based on (meth) acrylic resin or acrylamide resin, for example, and uses a crosslinking agent (for example, a titanium crosslinking agent and a zirconium crosslinking agent etc.) together as needed. Can be adjusted to 2.2.

Preferably, a (meth) acrylic resin or an acrylamide resin and a crosslinking agent (for example, a titanium crosslinking agent, a zirconium crosslinking agent, etc.) are added to a solvent having a boiling point of 150 ° C. or lower to obtain a viscosity of 300 mPa · s or more. A polarizing material is dispersed in a resin solution to obtain a coating material.

And when coating the said coating material to a base film by the bar coat method using a coating bar,

1000×L (L : 금속 도금 나노 와이어의 평균 길이) 이 되는 조건하에서의 도공이며,(1) As for the said coating, the contact length P of the circumference part of the said coating bar and the said base film is P

Coating under the conditions of 1000 × L (L: average length of the metal-plated nanowires),

W

10000×φ (φ : 금속 도금 나노 와이어의 평균 굵기) 인 것이 바람직하다.(2) As for the said coating bar, the groove | channel is equally formed in the area | region which the said coating bar and the said base film contact at least, The width W of the said groove | channel is 50 * φ

W

It is preferable that it is 10000xφ ((phi): average thickness of a metal plating nanowire).

The width W of the grooves needs to be sufficiently wider than the average thickness of the metal-plated nanowires, but when the width of the grooves is too wide or the contact length P is too short, the orientation becomes insufficient.

In the present invention, the coating bar in which the groove is formed is a dense wound of a wire having a constant diameter on the surface of the coating bar (so-called "wire bar"), or a groove having a constant width and depth on the surface of the coating bar itself. Formed at a constant pitch (so-called "meyer bar") is used. In addition, about the wire bar, the clearance gap between adjacent wires becomes a groove | channel.

W

10000×φ (φ : 금속 도금 나노 와이어의 평균 굵기) 가 되도록 설정한다. 50×φ＞W 이면, 홈의 폭 W 보다 금속 도금 나노 와이어의 평균 굵기 φ×50 이 커져, 금속 도금 나노 와이어의 단축이 홈에 들어가지 않기 때문에 배향시킬 수 없다. 또, W＞10000×φ 이면, 금속 도금 나노 와이어의 단축이 잘 배향되지 않게 된다. 홈의 폭 W 가 상기 조건을 만족시키면, 각 홈에 있어서 금속 도금 나노 와이어에 전단류가 일어나, 금속 도금 나노 와이어가 도공 방향으로 배향된다. 홈의 깊이에 대해서는, 금속 도금 나노 와이어의 평균 굵기 φ 보다 크면 특별히 한정되지 않는다.The groove has a width W of the groove 50 × φ

W

10000xφ (φ: average thickness of metal plating nanowires) is set. If it is 50 * phi> W, since the average thickness (phi) * 50 of a metal plating nanowire will become larger than the width | variety W of a groove | channel, since a short axis of a metal plating nanowire does not enter a groove | channel, it cannot orient. Moreover, if W> 10000xφ, the short axis of a metal plating nanowire will not be oriented well. When the width W of the groove satisfies the above conditions, shear flow occurs in the metal plated nanowires in each groove, and the metal plated nanowires are oriented in the coating direction. The depth of the groove is not particularly limited as long as it is larger than the average thickness φ of the metal-plated nanowires.

1000×L (L : 금속 도금 나노 와이어의 평균 길이) 의 조건을 만족시키도록 설정한다. 접촉 길이 P 가 상기 조건을 만족시키지 않으면, 충분히 전단류가 일어나지 않아, 금속 도금 나노 와이어를 배향률 80 ％ 이상으로 배향시키기가 어렵다.In the present invention, the contact length P between the circumference of the coating bar and the base film is P

It sets so that the conditions of 1000 * L (L: average length of metal plating nanowires) are satisfy | filled. If the contact length P does not satisfy the above conditions, shear flow does not sufficiently occur, and it is difficult to orient the metal plated nanowire at an orientation ratio of 80% or more.

150×L 를 만족시키도록 각각 조정하면 된다.The said contact length P is set so that the said conditions may be satisfy | filled by adjusting hold angle (theta) according to the diameter R of the coating bar to be used. In short, πR × θ / 360

What is necessary is just to adjust each so that 150xL may be satisfied.

The diameter R of the coating bar is 15? It is preferable that it is 200 mm. When the diameter of the coating bar is thinner than 15 mm, the adhesion between the coating bar and the substrate film tends to be poor under the influence of the bending elasticity of the substrate. Moreover, if it is 200 mm or more, since a coating bar becomes heavy and a load is applied to the motor of a coating machine, it is not preferable.

150×L 을 만족시킬 수 있으면 특별히 한정되지 않고, 도공 장치 등에 맞춰 적절히 결정되면 된다.For the holding angle θ, πR × θ / 360

It will not specifically limit, if it can satisfy | fill 150 * L, What is necessary is just to determine suitably according to a coating apparatus.

Although the thickness of a dry coating film is not limited, In order to exhibit preferable polarizing characteristic, 0.1 micrometer-? About 10 micrometers is preferable.

As for the polarizing material (metal plating nanowire) after orientation, it is preferable that the clearance gap between adjacent polarizing materials becomes less than the wavelength of light.

Moreover, it is preferable that the solvent used for a coating material has a boiling point lower than 150 degreeC, and is aliphatic alcohol, aliphatic ether, aliphatic ketone, fatty acid ester, aliphatic halide, aromatic alcohol, aromatic ether, aromatic ketone, aromatic ester, aromatic halide, etc. It is preferable that boiling point is 150 degrees C or less in it.

There is no restriction | limiting in particular as a base film which coats coating material as long as it can exhibit the polarization characteristic of the polarizing material of this invention, For example, glass and a resin film are mentioned. Moreover, in order to improve orientation, you may extend | stretch a film after 2 times or less after coating.

The film used as a base material has high visible light transmittance, preferably water resistant and heat resistant films, polyester films such as polyethylene terephthalate, cellulose ester films such as unsaponified cellulose acetate, cyclic polyolefin resin films, polycarbonate resin films, A polysulfone resin film, a polyether sulfone resin film, etc. are preferable.

In addition, in order to eliminate the influence of moisture and oxygen on the polarizing material and to prevent curling of the film, coating the coating material and orientating the polarizing material, and then using a resin adhesive, a polyester film and a cellulose ester film You may bond together and protect films, such as a cyclic polyolefin resin film, a polycarbonate resin film, a polysulfone resin film, and a polyether sulfone resin film. Moreover, in order to adhere on a liquid crystal cell, you may laminate | stack an inorganic layer, such as an inorganic oxide, and an organic polymer layer on this film, and may make it a gas barrier film.

Carrying out the invention  Form for

An Example and a comparative example are shown to the following, and this invention is concretely demonstrated to it. However, this invention is not limited to an Example.

Example  One

Metal-plated nanowires in which a metal plating layer was formed on the surface of a nanowire of cylindrical polymethyl methacrylate (PMMA) having an average thickness of 100 nm and an average length of 2 μm were dispersed and oriented in a coating film of an acrylic resin (refractive index 1.49). (See Figure 3). In addition, the refractive index of PMMA nanowires is 1.49. The coating film was dried to obtain a polarizing film. Hereinafter, it abbreviates as "coating film."

Table 1 shows the results of calculating the polarization performance of the coating film by commercial finite difference time domain method software.

(However, as for the nickel plated nanowires, the calculation in the case where a large amount of nickel plated nanowires are overlapped in the coating film has a large amount of calculation, and as shown in FIG. 3, the nanowire having an average thickness of 100 nm is 200 nm thick. The first film was oriented in parallel with an average pitch of 200 nm in one layer, the transmittance of one layer was determined by the finite difference time domain method, and the transmittance of 2.6 µm = 13 layer was determined by using the Lambert-Beer method. .)

Metal plating layer Filling Rate of Metal Plated Nanowires Coating
thickness p polarized light s polarized light Polarization degree
metal thickness reflectivity Transmittance reflectivity Transmittance Ni 3.5 nm 25vol% in coating cross section 2.6 μm - 97% ?0% 0.01% 91.29% Al 13 nm 36vol% in coating cross section 0.28 μm 3% 94% 74% 10% 80.77%

Table 1 of the degree of polarization was calculated by using, for the p-polarized light transmittance of the transmittance to the T _x, T _y and s-polarized light into, and simple substance transmittance is calculated from these T, p T _p transmittance and cross transmittance T _c. Specifically, it is as follows and the same also about another Example and a comparative example.

ㆍ Temperature transmittance T (%) = (T _x + T _y ) / 2

ㆍ para-permeability T _p (%) = (T _x ² + T _y ² ) / 2

ㆍ cross transmittance T _c (%) = T _x and T _y

[Formula 1]

Polarization%

From the result of Table 1, the performance as a polarizing plate of the coating film when the metal plating layer is made into nickel (3.5 nm thickness), and the performance as a brightness rising polarizing plate of the coating film when the metal plating layer is made into aluminum (13 nm thickness) are all favorable.

Example  2 ? 4 and Comparative example  One ? 2

A metal-plated nanowire in which a chromium plating layer was formed as a metal plating layer on the surface of a nanowire of cylindrical fluoroapatite (refractive index 1.635) having an average thickness of 100 nm and an average length of 20 μm was coated with an acrylic resin coating film (refractive index of 1.49 and thickness of 0.2 μm). ) And dispersed. The thickness of the chrome plating layer was changed for every Example and comparative example. Table 2 shows the results of evaluating the polarization performance of the coating film using a polarization analyzer (special order product) manufactured by Sigma Koki.

When the chromium plating layer is thin (Comparative Example 1), the reflectance of s-polarized light is low and sufficient polarization separation cannot be obtained. In addition, when the chromium plating layer is thick (Comparative Example 2), the reflectance of the s-polarized light is high and the transmittance is low, and polarization separation is sufficiently obtained, but the transmittance of the p-polarized light is lowered, which is not preferable because the loss as the polarizing element becomes large. Therefore, the thickness of the metal plating layer is 2? It is preferable to set it to 15 nm.

Example  5? 6 and Comparative example  3? 4

The metal-plated nanowire in which the aluminum plating layer of 7.5 micrometers thickness was formed in the nanowire of cylindrical PMMA (refractive index 1.49) of 20 micrometers in average length which changed average thickness was disperse | distributed and orientated in the coating film (refractive index 1.49) of acrylic resin. Table 3 shows the results of evaluating the polarization performance of the coating film using the polarization analyzer. The thickness of the coating film was basically 0.2 μm, and the average thickness of the nanowires was 0.3 μm in the case of 200 nm, and 0.35 μm in the case of 300 nm.

In the case where the average thickness of the nanowires is thin (Comparative Example 3), polarization separation is not sufficiently obtained. When the average thickness is thick (Comparative Example 4), the reflectance of the s-polarized light is large, polarization separation is obtained, and the polarization function is exhibited even at a thickness of 300 nm. However, in Comparative Example 4, since the transmittance of s-polarized light is also confirmed to some extent, the thickness of the more preferable nanowire is 100? 200 nm.

Example  7? 8 and Comparative example  5

A metal-plated nanowire having a 10 nm-thick chromium plating layer formed on the surface of a nanowire of cylindrical fluoroapatite (refractive index 1.635) having an average thickness of 100 nm and an average length thereof was coated with an acrylic resin coating film (refractive index of 1.49 and thickness of 0.2 μm). ) And dispersed. Table 4 shows the results of evaluating the polarization performance of the coating film using the polarization analyzer.

In the case where the average length of the nanowires is short (Comparative Example 5), the transmittance is higher than that of the s-polarized light, and polarization separation is not sufficiently obtained. When the average length of a nanowire is 2 micrometers or more, a polarization separation function is exhibited. However, 20 micrometers or less are preferable from the viewpoint of the ease of handling of a nanowire.

Example  9? 11 and Comparative example  6

The metal plating nanowire which formed the aluminum plating layer of 7.5 micrometer thickness in the cylindrical nanowire of average thickness 100nm and the average length 20micrometer was disperse | distributed and orientated in the resin coating film. Table 5 shows the results of evaluating the polarization performance of the coating film using the polarization analyzer. Each Example and the comparative example changed the refractive index difference, and the combination (nano wire / resin) is as follows.

Example 9 Magnesium Sulfate (Refractive Index 1.53) / Acrylic Type (Refractive Index 1.49)

Example 10 Potassium titanate (refractive index 2.2) / episulfide system (refractive index 1.8)

Example 11: Coat 10-thick episulfide (refractive index 1.8) on potassium titanate (refractive index 2.2) / thiourethane (refractive index 1.65)

Comparative Example 6: Potassium titanate (refractive index 2.2) / acrylic type (refractive index 1.49)

Although the polarization separation function is fully exhibited even if the refractive index difference between the nanowires and the coating film is somewhat large as in the example, if the refractive index difference is too large as in the comparative example, the transmittance of the s-polarized light increases and the performance when the luminance-enhanced polarizing plate is obtained is reduced.

Claims (11)

The polarizing material which consists of metal plating nanowire obtained by forming the metal plating layer of 1-15 nm in thickness on the surface of the nanowire which consists of a dielectric whose average thickness is 20-300 nm and average length is 0.4 micrometer or more. The method of claim 1,
And said dielectric has a refractive index of 1.47 to 2.2. The method of claim 1,
Wherein said dielectric has a core layer and a coating layer formed on the surface thereof, and the refractive index of the core layer is 1.47 to 2.2, and the refractive index of the coating layer is within nc ± 0.4 using the refractive index of the core layer as nc. . The method of claim 1,
The metal plating layer is a polarizing material which is a plating layer of at least one metal selected from the group consisting of nickel, chromium, zinc, tantalum, niobium, silver, iron and aluminum. Coating material for polarizing film manufacture containing the polarizing material of Claim 1. The method of claim 5, wherein
The said coating material contains resin, and the refractive index of the said resin is nd ± 0.4 within the refractive index of the said dielectric material, The coating material for polarizing film manufacture. The coating material for polarizing film manufacture containing the polarizing material and resin of Claim 3, and the refractive index of the said resin is within nc ± 0.4 using the refractive index of the said core layer as nc. The method of claim 5, wherein
The said coating material is a coating material for polarizing film manufacture containing a (meth) acrylic resin and a crosslinking agent. The polarizing film obtained by drying, after coating the coating material for polarizing film manufacture of Claim 5 on the surface of a base film. The method of claim 9,
The coating is a coating by a bar coat method using a coating bar,
(1) As for the said coating, the contact length P of the circumferential part of the said coating bar and the said base film is P,

It is coating under conditions to be 1000 * L (L: average length of metal plating nanowire),
(2) As for the said coating bar, the groove | channel is equally formed at least in the area | region which the said coating bar and the said base film contact, and the width W of the said groove | channel is 50xφ

W

Polarizing film which is 10000 * φ (φ: average thickness of metal plating nanowire). The method of claim 9,
The polarizing film used as a polarizing plate or a polarizing plate for luminance rise.

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