KR101989916B1 - An index matching film - Google Patents

Abstract

A base layer; And a light-quenching particle-containing coating layer laminated on the lower surface of the substrate layer, wherein the light-quenching particle-containing coating layer contains light-quenching particles having an average diameter of 1 탆 to 20 탆.

Description

An index matching film {AN INDEX MATCHING FILM}

Index matching film.

There is an increasing demand for a display device for inputting, manipulating and displaying information on a touch screen, such as a television, a computer, a mobile communication terminal, a smart phone, a car navigation system, and an ATM.

Various display devices such as a liquid crystal display (LCD), a plasma display (PDP), a cathode ray tube (CRT) and an electroluminescence display (EL) generally include a transparent conductive film and are typically made of indium tin oxide ITO) film or the like.

Recently, silver nano wire, grapheme, carbon nanotube (CNT), copper nano wire and the like are used as a material for forming a transparent electrode of a conductive film in place of such an ITO film. An electrode pattern formed by silver nano wire, The width and the width are relatively large, so that the pattern of the electrode can be visually seen by the consumer using the product, which may interfere with the image displayed on the display device, and the visibility may be lowered.

In addition, the conductive film is usually rolled up in a roll form or a plurality of films must be laminated and circulated. In the course of such a circulation process, when the transparent conductive film is applied to a touch screen panel, the performance of the transparent conductive film There is a problem that the performance is deteriorated.

In one embodiment of the present invention, there is provided an index matching film simultaneously realizing excellent visibility and good anti-blocking property.

In one embodiment of the invention, a substrate layer; And a light-quenching particle-containing coating layer laminated on the lower surface of the substrate layer, wherein the light-quenching particle-containing coating layer comprises an index matching film containing light-extinguishing particles having an average diameter of about 1 μm to about 20 μm do.

And the light-extinguishing particle-containing coating layer may contain about 1 wt% to about 50 wt% of the light-extinguishing particles.

Wherein the light-extinguishing particles are selected from the group consisting of silicon dioxide; Wax; Organic or inorganic pigments; And a combination of these.

The thickness of the extinction particle-containing coating layer may be about 1 탆 to about 20 탆.

And the lower surface of the light-extinguishing particle-containing coating layer may include a protrusion formed by the light-extinguishing particle.

The average height of the protrusions may be between about 5 nm and about 100 nm.

The index matching film may have a light transmittance of about 85% to about 95%.

Also, the index matching film may have a haze from about 0.1% to about 5.0%.

The light-emitting particle-containing coating layer may further comprise an acrylic resin.

And a hard coating layer may be further formed on the base layer.

The hard coating layer may be formed by photocuring or thermosetting a composition for hard coating containing an acrylic compound.

The base layer may be formed of a material selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polymethylmethacrylate (PMMA), polystyrene, polyvinylchloride, polyethersulfone (PES) And combinations of these.

The index matching film can simultaneously realize excellent visibility and good anti-blocking property.

1 is a schematic cross-sectional view of an index matching film according to one embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

In the drawings, the thickness is enlarged to clearly represent the layers and regions. In the drawings, for the convenience of explanation, the thicknesses of some layers and regions are exaggerated.

Hereinafter, the formation of any structure in the "upper (or lower)" or the "upper (or lower)" of the substrate means that any structure is formed in contact with the upper surface (or lower surface) of the substrate However, the present invention is not limited to not including other configurations between the substrate and any structure formed on (or under) the substrate.

1 schematically shows a cross-sectional view of an index matching film according to an embodiment of the present invention.

In one embodiment of the invention, a substrate layer; And a light-quenching particle-containing coating layer laminated on the lower surface of the substrate layer, wherein the light-quenching particle-containing coating layer provides an index-matching film containing light-quenching particles having an average diameter of about 1 탆 to about 20 탆 . Specifically, the average diameter of the light-extinguishing particles may be about 1 탆 to about 10 탆.

Recently, silver nano wire, grapheme, carbon nanotube (CNT), copper nano wire and the like have been used as a material for forming a transparent electrode of a conductive film in place of the ITO film. An electrode pattern formed by silver nano wire or the like has a width The width of the electrode is relatively large, so that the pattern of the electrode can be visually seen by the consumer using the product, which may interfere with the image displayed on the display device, and the visibility may be greatly deteriorated.

In addition, the transparent conductive film may be rolled up in a roll form, or a plurality of films may be laminated and circulated, thereby causing the transparent conductive films to adhere to each other. In order to apply the transparent conductive film to the touch screen panel or the like, There is a problem that the performance of the display device may be remarkably deteriorated.

Thus, in one embodiment of the present invention, the index matching film comprises a base layer; And a light-quenching particle-containing coating layer laminated on the lower surface of the substrate layer, wherein the light-quenching particle-containing coating layer contains optical fine particles having an average diameter of, for example, about 1 탆 to about 20 탆, So that the electrode pattern can be prevented from being visually seen by the consumer using the product, thereby providing excellent visibility.

At the same time, as described later, the light-emitting particle-containing coating layer can be formed with protrusions by the light-emitting particles at the bottom, and thus wound in a roll form, or when a plurality of films are laminated, It is possible to reduce the area of the index matching film to be formed at a weak level so that it is possible to realize an excellent anti-blocking property for effectively preventing the index matching film from being damaged in the process of unfolding or peeling the index matching film.

Specifically, when the average diameter of the light-extinguishing particles is less than about 1 탆, it is difficult to observe the electrode pattern sufficiently and can be observed with the naked eye by the consumer. Also, since the anti-blocking property is low, If the thickness is more than about 20 탆, the haze is excessively increased and the index matching property, that is, the visibility may deteriorate.

The light-extinguishing particles include, for example, protrusions on the surface of a coating layer and concavities and convexities formed by gathering protrusions on the surface of the coating layer to refract light incident from the outside in various directions to scatter light, Refers to a compound in which a plurality of fine particles are clustered together.

Wherein the light-extinguishing particles are silica particles; Wax; Organic or inorganic pigments; And a combination of these.

The wax may be at least one selected from the group consisting of, for example, melamine wax, (meth) acrylic wax, acryl-styrene copolymer wax, polycarbonate wax, polyethylene wax, polystyrene wax, .

The organic or inorganic pigments include, for example, monoazo based pigments, diazo based pigments, phthalocyanine pigments, anthraquinone pigments, quinacridone pigments, perylene pigments, nitroso based pigment, carbazole dioxazine based pigment, carbon black, graphene, carbon nanotube (CNT), titanium dioxide and the like.

The light extinction particle-containing coating layer may further comprise an acrylic compound. That is, the light-emitting particle-containing coating layer is formed of an acrylic compound; And light emitting particles having an average diameter of from about 1 m to about 100 m.

The acrylic compound may include at least one selected from the group consisting of acrylic monomers, oligomers, resins, and combinations thereof.

The acrylic compound includes, for example, dipentaerythritol hexa (meth) acrylate, dipentaerythritol, penta (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (Meth) acrylate, glycerol tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate tri (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol Acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) , Urethane acrylate oligomers, epoxy acrylate oligomers, and the like, but are not limited thereto.

The light-extinguishing particle-containing coating layer may contain, for example, about 1 wt% to about 50 wt% of the light-extinguishing particles, and specifically about 1 wt% to about 10 wt%. The light transmittance and the haze are suitably adjusted to realize a sufficiently high visibility and a protruding portion is suitably formed on the lower surface of the light-emitting particle-containing coating layer and wound in a roll form or a plurality of sheets are stacked It is possible to reduce the contact area therebetween and to achieve a high anti-blocking property.

The lower surface of the light-emitting particle-containing coating layer may include a protrusion formed by the light-absorbing particles, so that the upper and lower surfaces of the index-matching film in the course of flowing the index- It is possible to effectively reduce the contact area, thereby realizing excellent anti-blocking properties.

The average height of the protrusions can be about 5 nm to about 100 nm. By having an average height within the above-mentioned range, it is possible to realize sufficient blocking property while forming an appropriate level without increasing the surface haze value, thereby realizing excellent optical properties.

The average height of the protrusions means a value obtained by averaging the heights of the protrusions, and the height of the protrusions means the length of the protrusions on the bottom surface at a point where the protrusions protrude to the maximum from the bottom surface of the light-emitting particle containing coating layer.

Wherein the coating composition is a photoinitiator or a thermal initiator; solvent; Other additives, and combinations thereof.

The other additives may further include at least one selected from the group consisting of, for example, antioxidants, UV absorbers, light stabilizers, thermal polymerization inhibitors, leveling agents, surfactants, lubricants, antifouling agents and combinations thereof .

The photoinitiator or the thermal initiator may be of a kind known in the art, for example, the photoinitiator may be 2-methyl-1- [4- (methylthio) phenyl] 2- morpholinepropanone- Phenyl ketone, benzyldimethyl ketal, 2-hydroxy-2-methyl-1-phenyl-1-one, 4-hydroxycyclophenyl ketone, dimethoxy- Amine, carbazole, 3-methylacetophenone, 4-quinoloacetophenone, 4,4-dimethoxyacetophenone, 4,4-diaminobenzophenone, 1-hydroxycyclohexylphenylketone, And combinations thereof.

The solvent is not limited to methanol, ethanol, isopropanol, butanol, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, cyclohexanone and the like.

The thickness of the extinction particle-containing coating layer may be about 1 탆 to about 20 탆. By having the thickness within the above range, the display device can be sufficiently protected from external stimuli and stress without excessively increasing the thickness of the index matching film.

Further, a hard coating layer may be further formed on the base layer. The hard coating layer may be formed by photocuring or thermosetting a composition for hard coating containing an acrylic compound. The acrylic compound may be the same as described above, and a kind known in the art may be used without any particular limitation. have.

The composition for hard coating includes a photoinitiator or a thermal initiator; solvent; Other additives, and combinations thereof. ≪ Desc / Clms Page number 7 > The photoinitiator, the thermal initiator, the solvent, and the other additives may be of the same kind as described above, but may be of any kind known in the art depending on the purpose and use of the invention, and are not particularly limited.

The thickness of the hard coating layer may be about 1 [mu] m to about 20 [mu] m. By having the thickness within the above range, excellent surface hardness can be realized without excessively increasing the thickness of the index matching film.

The hard coating layer may further include silica particles having an average diameter of about 1 nm to about 50 nm, thereby achieving excellent surface hardness of the index matching film and maintaining a proper haze value.

The surface hardness of the hard coating layer may be from about H to about 4H, and the surface hardness may mean a value measured according to ISO 15184. By having the surface hardness within the above range, excellent surface hardness can be realized, and excellent surface characteristics can be maintained when rolled or bent in a roll form. Specifically, if the surface hardness of the hard coat layer is more than about 4H, if the hard coat layer is rolled or bent in a roll form, cracks may be generated on the surface of the hard coat layer, resulting in performance problems.

The base layer may be a transparent plastic film, and may be a transparent plastic film such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polymethylmethacrylate (PMMA), polystyrene, polyvinylchloride, But is not limited to, at least one selected from the group consisting of polyethersulfone (PES), polyethylene, polypropylene, and combinations thereof.

The thickness of the substrate layer may be from about 15 占 퐉 to about 300 占 퐉, and specifically from about 30 占 퐉 to about 200 占 퐉. By having the thickness in the above range, the light-emitting particle containing coating layer can be sufficiently supported without excessively increasing the total thickness of the index matching film.

The index matching film may have a light transmittance of about 85% to about 95%, and the light transmittance may mean a value measured according to ISO14782. (ITO) electrode existing under the index matching film is formed on the silver nano wire (Al (ITO)) by maintaining the optical transmittance within the above range by appropriately adjusting the visibility of the index matching film, -doped ZnO, AZO), grapheme, carbon nanotube (CNT), copper nanowire, and the like can be effectively prevented.

Also, the index matching film may have a haze of about 0.1% to about 5.0%, and the haze may refer to a value measured according to ISO 13468 .

(ITO) electrode existing at the bottom of the index matching film is formed on the silver nano wire (Al (ITO)) by keeping the visibility of the index matching film appropriately by keeping the haze value within the above range, -doped ZnO, AZO), grapheme, carbon nanotube (CNT), copper nanowire, and the like can be effectively prevented.

Hereinafter, specific embodiments of the present invention will be described. It should be understood, however, that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Example

Example  One

A hard coating composition including an acrylic compound, silica particles having an average diameter of 10 to 15 nm (silica, optisol), a photoinitiator, and a solvent was coated on one side of a PET film having a thickness of 100 mu m, A coating composition containing an acrylic compound, a light-emitting particle having an average diameter of 10 mu m, and a photoinitiator is coated on the other surface of the PET film and then photocured to form a hard coating layer of a light- A light-emitting particle-containing coating layer sequentially formed by forming a particle-containing coating layer; A substrate layer and a hard coat layer were laminated.

Specifically, the light-extinguishing particles include particles formed of a silicon dioxide material (EVONIK, Aerosil) and wax materials of a methacrylic polymer series (PMMA polymer series) (BYK Corp., Ceraflor) Containing coating layer had an average height of 15 nm.

Comparative Example 1 (when the average of the light-absorbing particles included in the light-emitting particle-containing coating layer was less than the average)

An index-matched film was produced under the same conditions and in the same manner as in Example 1, except that the average diameter of the light-emitting particles contained in the light-emitting particle-containing coating layer was 0.8 μm.

The protrusions formed on the lower surface of the light-emitting particle-containing coating layer had an average height of 4 nm.

Comparative Example 2 (when the average of the light-absorbing particles contained in the light-extinguishing particle-containing coating layer was exceeded)

An index matching film was produced under the same conditions and in the same manner as in Example 1, except that the light-emitting particles contained in the light-emitting particle-containing coating layer had an average diameter of 22 mu m.

The protrusions formed on the lower surface of the light-emitting particle-containing coating layer had an average height of 500 nm.

evaluation

The properties of the index-matched films of Example 1 and Comparative Examples 1 and 2 were evaluated and are shown in Table 1 below.

(Light transmittance)

Measurement method: The index matching films of Example 1 and Comparative Examples 1 and 2 were measured using a haze meter (Nippon Denshoku, NDH5000) according to the measuring method according to (ASTM D1003).

(Hayes)

Measurement method: The index matching films of Example 1 and Comparative Examples 1 and 2 were measured using a haze meter (Nippon Denshoku, NDH5000) according to the measuring method according to (ASTM D1003).

 (Surface hardness)

Measurement method: The hard coat layer of the index matching film of Example 1 and Comparative Examples 1 and 2 was measured on the basis of a Mitsubishi pencil according to ISO 15184. Mitsubishi 6B to 9H (17 pieces), 750g load standard.

(Anti-blocking property)

Measurement method: When the index matching film was rolled up in a rolled state and allowed to stand at 60 캜 for 48 hours and then unwound again, the hard coat layer and the light-emitting particle-containing coating layer were easily separated and the performance of the index- The case where the outer appearance is maintained and the anti-blocking property is excellent is shown as "", the hard coating layer and the blocking layer do not fall well, the performance of the index matching film is deteriorated, X ".

Light transmittance (%) Haze (%) Surface hardness Anti-blocking property Example 1 90.88 4 3H ○ Comparative Example 1 91.21 3 3H X Comparative Example 2 87.25 35 3H ○

As shown in Table 1, the index matching film according to Example 1 has excellent light transmittance and appropriate haze, so that the electrode pattern can not be seen by the naked eye, so that it has excellent index matching property and visibility. At the same time, It can be clearly predicted that the physical properties of the index matching film will be uniform even after the distribution process.

On the other hand, the index-matching film according to Comparative Example 1 was suitable for haze, but it was clearly anticipated that the anti-blocking property was remarkably low, The index matching film according to the present invention can be clearly predicted that the haze is excessively high, the optical properties are inferior, and the index matching property and visibility are considerably lowered.

100: index matching film
110: light-emitting particle-containing coating layer
120: substrate layer
130: hard coat layer

Claims (12)

A base layer; And a light-emitting particle-containing coating layer laminated on the lower surface of the substrate layer,
Wherein the light-extinguishing particle-containing coating layer contains light-extinguishing particles having an average diameter of 10 mu m to 20 mu m,
Wherein the lower surface of the light-extinguishing particle-containing coating layer includes a protrusion formed by the light-extinguishing particle,
Wherein the average height of the protrusions is 5 nm to 100 nm
Index matching film.
The method according to claim 1,
Wherein the light-extinguishing particle-containing coating layer contains 1 wt% to 50 wt% of the light-extinguishing particles
Index matching film.
The method according to claim 1,
Wherein the light-extinguishing particles are selected from the group consisting of silicon dioxide; Wax; Organic or inorganic pigments; And at least one selected from the group consisting of combinations thereof.
Index matching film.
delete delete delete The method according to claim 1,
Having a light transmittance of 85% to 95%
Index matching film.
The method according to claim 1,
0.1% to 5.0% haze
Index matching film.
The method according to claim 1,
Wherein the light-emitting particle-containing coating layer further comprises an acrylic resin
Index matching film.
The method according to claim 1,
Further comprising a hard coat layer on the substrate layer
Index matching film.
11. The method of claim 10,
The hard coating layer may be formed by photocuring or thermosetting a composition for hard coating containing an acrylic compound
Index matching film.
The method according to claim 1,
Wherein the base layer is at least one selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polymethylmethacrylate (PMMA), polystyrene, polyvinylchloride, polyethersulfone (PES) And at least one selected from the group consisting of combinations thereof
Index matching film.

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