KR102613008B1 - Conductive film and method for preparing the same - Google Patents

Abstract

This application relates to conductive films and their manufacturing methods. The conductive film has excellent electrical properties and transparency, and can improve the fairness of the roll-to-roll process.

Description

Conductive film and method for manufacturing the same {Conductive film and method for preparing the same}

This application relates to conductive films and their manufacturing methods.

Transparent electrodes are used in various fields such as batteries, touch panels, and displays. Generally, transparent electrodes are manufactured by forming a conductive layer such as ITO on a transparent substrate made of glass or plastic. In addition, the transparent electrode may further include a layer (functional layer) that exerts a predetermined function between the transparent substrate and the conductive layer. In this case, the transparent electrode can be manufactured by forming a conductive layer through vapor deposition while unwinding a film including a transparent substrate and a functional layer through a roll-to-roll method. In this roll-to-roll process, abnormal running of the film may occur due to friction between the running roll and the functional layer, and as a result, defects such as wrinkles or folding of the transparent electrode may occur.

One purpose of the present application is to provide a conductive film that can improve the manufacturing process of the conductive film using roll-to-roll.

Another object of the present application is to provide a conductive film with excellent electrical properties and transparency.

The above objects and other objects of the present application can all be solved by the present application described in detail below.

In one example relating to this application, this application relates to transparent electrodes, i.e. transparent conductive films. Specifically, this application relates to a conductive film including a conductive layer and a functional layer.

In this application, “transparent” means that the transmittance to visible light with a wavelength in the range of 380 nm to 780 nm, specifically 550 nm, is 80% or more or 85% or more. That is, the transparent conductive film of the present application satisfies the above transmittance.

The conductive layer is a layer having electrical conductivity and may refer to a layer that can function as a so-called electrode. As long as it has transparency and electrical conductivity, the type of material forming the conductive layer is not particularly limited.

In one example, the conductive layer may include transparent conductive metal oxide. For example, the conductive layer is ITO (Indium Tin Oxide), In ₂ O ₃ (indium oxide), IGO (indium galium oxide), FTO (Fluor doped Tin Oxide), AZO (Aluminum doped Zinc Oxide), GZO (Galium It may include doped zinc oxide (ATO), antimony doped tin oxide (ATO), indium doped zinc oxide (IZO), niobium doped titanium oxide (NTO), zinc oxide (ZnO), or cesium tungsten oxide (CTO). However, the types of transparent conductive metal oxide are not limited to those listed above.

In one example, the conductive layer may include one or more of the transparent conductive metal oxides mentioned above. Specifically, one layer may include two or more transparent conductive metal oxides. Alternatively, the conductive layer may have a stacked structure composed of two or more layers, and each layer may include different transparent conductive metal oxides.

In one example, the conductive layer may have a predetermined pattern. For example, the conductive layer is a region formed through a method such as etching or photolithography, and may have both a region where electricity flows and a region where electricity does not flow.

The conductive layer can have a thickness sufficient to meet the haze and/or transparency described above and to provide sufficient surface resistance and mechanical strength to function as a conductive layer. In one example, the conductive layer may have a thickness of 300 nm or less. If the thickness exceeds the above thickness, the surface resistance can be relatively lowered, but the light transmittance of the conductive layer may decrease and cracks may easily occur. Additionally, if the thickness exceeds 300 nm or more, it is undesirable in terms of cost and fairness. Specifically, in the present application, in order to satisfy the appropriate level of surface resistance described below and at the same time sufficiently secure transparency and mechanical strength, the thickness is 250 nm or less, 200 nm or less, 150 nm or less, 100 nm or less, and 50 nm or less. A conductive layer of any thickness can be used. The lower limit of the thickness of the conductive layer is not particularly limited, but may be, for example, 10 nm or more, 15 nm or more, 20 nm or more, 25 nm or more, 30 nm or more, 35 nm or more, or 40 nm or more.

In one example, the conductive layer may have a surface resistance in the range of 40 to 500 Ω/□. When the above range is satisfied, an appropriate level of electrical conductivity can be provided. According to the present application, the surface resistance of the conductive layer as described above can be secured while the conductive layer is stably formed through improved roll-to-roll processability as described below.

The transparent conductive film includes an index matching layer as a functional layer. The index matching layer may be located on one side of the conductive layer.

Unless specifically defined otherwise, the terms “on” or “on” used in relation to interlayer lamination positions in this application refer not only to the case where a component is located directly above another component, but also to a third layer between these components. It can be used to include even cases where composition is involved.

The index matching layer can improve the optical properties of the conductive film. Specifically, as described above, when the conductive layer has a pattern, it can simultaneously have a region where the conductive metal oxide is present and a region where the conductive metal oxide is etched, and a difference in reflectivity exists between these regions. As explained below, the index matching layer having a matrix and particles functions to conceal the visible pattern by reducing the difference in reflectivity of these areas by optical interference, refraction or scattering and at the same time improves the transmittance of the conductive film. In addition, in the process of providing a conductive film, when forming a conductive layer, which is a vapor deposition layer, directly on a substrate (glass or plastic), damage to the substrate surface may occur due to the plasma of the vacuum process or VOC (vcolatile organic chemicals) generated during the process may occur. ) may cause the physical properties of the conductive layer to deteriorate. When the index matching layer is located between the base layer and the conductive layer, it can serve as a kind of buffer for the deposition process, so it has the advantage of preventing the problems mentioned above. there is.

The index matching layer includes a matrix (M) and particles (P). The matrix forms a continuous phase in the index matching layer, and the particles may be dispersed within the continuous phase. Specifically, the index matching layer may include particles whose portion is exposed to the outside of the matrix. That is, the index matching layer includes a matrix (M) and particles (P), and the particles (P) may have a protruding surface (S).

The index matching layer includes particles forming a protruding surface.

Specifically, the index matching layer having a surface (S) on which the particles (P) protrude may include particles (P1) that satisfy the following relational equation 1. When the particles (P1) are included in a predetermined amount, a surface (S) having surface irregularities can be formed.

[Relationship 1]

(D _P1 /T _M ) > 1

In equation 1, D _P1 refers to the particle size of the particles P1 included in the index matching layer, and T _M refers to the thickness of the matrix of the index matching layer.

The particle size of the particles can be measured according to known methods. For example, the particle size can be measured or defined by BET (Brunauer-Emmett-Telle) specific surface area analysis. In one example, the relational equation 1 may mean the relationship between the highest measured matrix thickness (T _M ) in the matrix space actually occupied by the particles having a predetermined particle size, or the matrix thickness actually occupied by the particles having a predetermined particle size. It may also mean the relationship with the average thickness (T _M ) of the matrix measured in space. In another example, the relational expression 1 may mean the relationship between the average thickness value (T _M ) of the matrix measured according to the above-mentioned method and the particle size of the particles used.

That is, the index matching layer may include particles P1 having a particle diameter larger than the thickness of the matrix.

Particles (P1) with a particle size that satisfies the above equation 1 may form irregularities on the surface of the index matching layer. In addition, the irregularities can provide maximum surface roughness and/or friction coefficient as described below. When forming a conductive layer such as ITO on the index matching layer unrolled through roll-to-roll, process defects may occur due to friction between the running roll and the index matching layer. However, in the present application, since an index matching layer having a surface (S) on which particles satisfying the above relational expression 1 protrudes is used, static electricity that may occur when the index matching layer wound on a roll is unwound is reduced, and the index matching layer Friction can also be reduced. As a result, roll-to-roll process defects that occurred in the prior art can be prevented and the quality of the conductive film can be improved.

In one example, the index matching layer may include 0.5 to 15 parts by weight of particles (P1) satisfying the relational equation 1, based on 100 parts by weight of the resin component for forming the matrix of the index matching layer. At this time, the content ratio is the weight ratio to the solid content in the composition for forming the index matching layer. For example, the content of the particles (P1) may be 1 part by weight or more, 2 parts by weight or more, 3 parts by weight or more, 4 parts by weight or more, or 5 parts by weight or more, and the upper limit is 14 parts by weight or less, 13 parts by weight or less. Hereinafter, it may be 12 parts by weight or less, 11 parts by weight or less, or 10 parts by weight or less. If the particle content exceeds the above range, the transmittance (transparency) of the conductive film may decrease as the haze of the conductive film increases. Additionally, excessive particles may weaken the strength of the conductive layer formed on the index matching layer, thereby deteriorating the quality of the conductive film.

In one example, the particles (P1) have a thickness of 2.5 times or less, 2.4 times or less, 2.3 times or less, 2.2 times or less, 2.1 times or less, 2.0 times or less, and 1.9 times the thickness (T _M ) of the matrix of the index matching layer. Hereinafter, it may have a diameter (D _P1 ) of 1.8 times or less, 1.7 times or less, 1.6 times or less, 1.5 times or less, 1.4 times or less, 1.3 times or less, 1.2 times or less, or 1.1 times or less.

In one example, the index matching layer may simultaneously include particles that contribute to improving the optical properties of the film in addition to the particles (P1) forming the protruding surface. Specifically, the index matching layer may further include particles (P2) that satisfy the following relational equation 2.

[Relational Expression 2]

(D _P2 /T _M ) ≤ 1

In equation 2, D _P2 refers to the particle size of the particles P2 included in the index matching layer, and T _M refers to the thickness of the matrix of the index matching layer. The measurement method for particle size, thickness, and their relationship is the same as described above.

Particles (P2) satisfying Relation 2 can provide transparency to the index matching layer by inducing light scattering.

In one example, the index matching layer may include 200 parts by weight or less of particles (P2) satisfying the relational equation 2, based on 100 parts by weight of the resin component for forming the matrix of the index matching layer. At this time, the content ratio is the weight ratio to the solid content in the composition for forming the index matching layer. For example, the content of the particles (P2) is 0 parts by weight or more, 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, 20 parts by weight or more, 25 parts by weight or more, 30 parts by weight or more, 35 parts by weight or more. or more, 40 parts by weight or more, 45 parts by weight or more, 50 parts by weight or more, 55 parts by weight or more, 60 parts by weight or more, 65 parts by weight or more, 70 parts by weight or more, 75 parts by weight or more, 80 parts by weight or more, 85 parts by weight or more It may contain more than 90 parts by weight, more than 95 parts by weight, or more than 100 parts by weight. And the upper limit of the content is, for example, 190 parts by weight or less, 180 parts by weight or less, 170 parts by weight or less, 160 parts by weight or less, 150 parts by weight or less, 140 parts by weight or less, 130 parts by weight or less, 120 parts by weight or less. It may be 110 parts by weight or less. When particles (P2) are used in the above content range, appropriate transparency and transmittance can be secured. If the particle content exceeds the above range, a change in color (yellow index) may occur. Additionally, excessive particles may weaken the strength of the conductive layer formed on the index matching layer, thereby deteriorating the quality of the conductive film.

In the present application, the index matching layer having the surface irregularities may satisfy predetermined characteristics. In other words, the conductive film may contain particles so as to satisfy the following characteristics within a range that does not impair the technical spirit of the present application.

In one example, the surface (S) of the index matching layer including particles satisfying a predetermined relational expression as described above may have a maximum surface roughness (R _max ) within the range of 15 to 100 nm. The maximum surface roughness refers to the difference between the maximum and minimum heights of the surface (S) of the index matching layer, and can be measured according to the method described in the experimental examples below. Specifically, the maximum surface roughness of the surface (S) is 16 nm or more, 17 nm or more, 18 nm or more, 19 nm or more, 20 nm or more, 21 nm or more, 22 nm or more, 23 nm or more, 24 nm or more, or 25 nm or more. It may be more than nm. And, the upper limit may be, for example, 90 nm or less, 85 nm or less, 80 nm or less, 75 nm or less, 70 nm or less, 65 nm or less, 60 nm or less, 55 nm or less, or 50 nm or less. When the surface (S) with particles exposed to the outside of the matrix has a maximum surface roughness within the above range, it can have a friction coefficient at a level described below, thereby preventing defects in the roll-to-roll process, and in the experiment below As confirmed in the examples, low haze can be provided for transparent conductive films.

In one example, the surface S may face one side of the conductive layer or may be in direct contact with one side of the conductive layer. When a conductive layer is formed on the surface S, roll-to-roll processability can be improved and damage to the conductive layer can be prevented.

In one example, the number of particles observed on the surface (S) of the index matching layer that satisfies the surface roughness may be within the range of 0.2 to 3.0 particles/㎛ ² . When the above range is satisfied, a friction coefficient and/or surface roughness sufficient to achieve the purpose of the present application can be provided while securing an appropriate level of film transparency. For example, the number of particles (P1) observed per unit area (㎛ ² ) on the surface (S) of the index matching layer is 0.3 particles / ㎛ ² or more, 0.4 particles / ㎛ ² or more, 0.5 particles / ㎛ ² or more. , 0.6 pieces/μm ² or more, 0.7 pieces/μm ² or more, 0.8 pieces/μm ² or more, 0.9 pieces/μm ² or more, 1.0 pieces/μm ² or more, 1.1 pieces/μm ^{2 or} more, 1.2 pieces/μm ² or more, 1.3 pieces/μm ² or more, 1.4 pieces/μm ² or more, 1.5 pieces/μm ^{2 or} more, 1.6 pieces/μm ² or more, 1.7 pieces/μm ^{2 or} more, 1.8 pieces/μm ² or more, 1.9 pieces/μm ² or more, or It may be 2.0 pieces/μm ² or more, and may be 2.9 pieces/μm ² or less, 2.8 pieces/μm ² or less, 2.7 pieces/μm ² or less, or 2.6 pieces/μm ² or less. If the number of particles exceeds the above range, it means that the number of particles protruding from the surface (S) may be excessive, which may lower the strength of the index matching layer or conductive film and may even have a negative effect on processability. . Additionally, if the number of particles is less than the above range, it may be difficult to achieve the purpose of the present application. However, since the number of particles as described above is an average value of the number of particles observed in different areas as explained in the experimental examples below, the number of particles per unit area is index matched if the particles that satisfy the above relational equation 1 It is only one of the criteria for determining whether it is included in the layer and whether appropriate surface roughness and/or friction coefficient can be secured to achieve the purpose of this application.

In one example, the index matching layer that satisfies the surface roughness may have a coefficient of static friction within a predetermined range. Specifically, the surface (S) of the index matching layer may have a static friction coefficient of 1.0 or less. More specifically, the friction coefficient may be 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, or 0.5 or less. For example, the friction coefficient may be measured more than once. During measurement, the coefficient of friction may show a constant value. Alternatively, the friction coefficient value of a certain value measured two or more times may appear to converge to one value. The static friction coefficient can be measured in the same way as in the experimental example below.

The shape of the particles P used to form the index matching layer is not particularly limited, as long as the above-described relational expression and numerical values for the concave-convex shape can be satisfied. For example, the shape of the particles P included in the index matching layer may be plate-shaped, needle-shaped, amorphous, or spherical.

In one example, the particle (P) may be an isotropic spherical particle. In the case of having an isotropic spherical shape, regardless of the arrangement direction of the particles in the index matching layer, the degree of distribution or shape of the particles can be maintained uniformly within the matrix, which can be advantageous in satisfying the characteristics of the index matching layer required in the present application. there is.

The type of particles (P) used to form the index matching layer is not particularly limited, as long as there is no obstacle to satisfying the above-described relations 1 and 2. In one example, the particles include inorganic particles such as NaF, MgF ₂ , CaF ₂ , BaF ₂ , SiO ₂ , CeF ₃ , Al ₂ O ₃ , ZrO _{2, TiO 2 ,} ZnS, ZnSe, or Ta ₂ O ₅ can be used In another example, the particles may be organic-inorganic hybrid particles such as alkoxy silane. In another example, two or more particles selected from the group consisting of those listed may be used as the particles.

In one example, the refractive index of the particles may be in the range of 1.30 to 2.7, and considering the desired effect, the refractive index and diameter of each particle may be appropriately adjusted.

In one example, the index matching layer may be a cured product of a composition containing a curable resin and particles. In this case, the matrix may be of composition derived from a curable resin.

The type of curable resin is not particularly limited. For example, silicone resin, acrylic resin, epoxy resin, and/or urethane resin can be used to form the matrix. The composition forming the matrix by the curable functional group may be heat-cured or UV-cured, or heat-cured and UV-cured together.

The composition may include a curing agent or initiator. A curing agent or initiator can cure the above-mentioned organic and inorganic materials, for example, heat curing, UV curing, or heat and UV curing.

The curing agent may be, for example, one or more types of amine curing agents, imidazole curing agents, phenol curing agents, phosphorus curing agents, or acid anhydride curing agents, but is not limited thereto.

In one example, the curing agent may be an imidazole compound that is solid at room temperature and has a melting point or decomposition temperature of 80°C or higher. Such compounds include, for example, 2-methyl imidazole, 2-heptadecyl imidazole, 2-phenyl imidazole, 2-phenyl-4-methyl imidazole or 1-cyanoethyl-2-phenyl imidazole, etc. This may be exemplified, but is not limited thereto. The content of the hardener may be selected depending on the composition of the composition, for example, the type or ratio of organic matter.

Additionally, the initiator may include a cationic initiator or a radical initiator that is decomposed by heat or UV to create a substance that promotes the reaction.

The cationic initiator may be a cationic photoinitiator or a cationic thermal initiator. As the cationic photoinitiator, an ionized cationic initiator of the onium salt or organometallic salt series, or an organic silane or latent sulfonic acid series or a non-ionized cationic photopolymerization initiator may be used. Examples of the onium salt series initiator include diaryliodonium salt, triarylsulfonium salt, or aryldiazonium salt, and may be used as an organometallic salt series initiator. Examples of zero include iron arene, and examples of organic silane-based initiators include o-nitrobenzyl triaryl silyl ether and triaryl silyl peroxide. Alternatively, acyl silane may be used, and latent sulfuric acid-based initiators may include α-sulfonyloxy ketone or α-hydroxymethylbenzoin sulfonate, but are not limited thereto. .

Cationic thermal initiators include imidazole and quaternary ammonium salts of super acids (e.g., quaternary ammonium salts of SbF6) and mixtures thereof.

The radical initiator may be a photoinitiator or a thermoinitiator. The specific type of photoinitiator may be appropriately selected considering curing speed and yellowing potential. For example, benzoin-based, hydroxy ketone-based, amino ketone-based, or phosphine oxide-based photoinitiators can be used, and specifically, benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether. , Benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylanino acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2 -Hydroxy-2-methyl-1-phenylpropan-1one, 1-hydroxycyclohexylphenylketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propane-1- On, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4 -Dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetophenone dimethylketal, p-dimethylamino benzoic acid ester, oligo[2-hydroxy-2-methyl-1-[4-(1-methyl Vinyl)phenyl]propanone] and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide can be used.

In one example, the composition for forming the index matching layer may include a photocurable compound. For example, it may include monofunctional (meth)acrylate or polyfunctional (meth)acrylate. Monofunctional (meth)acrylates include alkyl (meth)acrylate, more specifically, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, Uryl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate or isostearyl (meth)acrylate can be used. In addition, polyfunctional acrylates include polyfunctional urethane acrylate, ethylene glycol diacrylate (EGDA), dipropylene glycol diacrylate (DPGDA), and epoxies such as bisphenol A or bisphenol F. Epoxy acrylate, polyether triacrylate, pentaerythritol tri/tetraacrylate (PETA), dipentaerythritol hexa-acrylate (DPHA), trimethylolpropane triacrylate ( trimethylolpropane triacrylate (TMPTA) and hexamethylene diacrylate (HDDA) may be used. However, it is not limited to the materials listed above.

In one example, when the composition comprising the resin component is cured, the matrix formed from the resin component has a thickness of at least 20 nm, at least 25 nm, at least 30 nm, at least 35 nm, at least 40 nm, or at least 45 nm. You can have it. In the present application, the thickness of the matrix is determined by known methods, such as cross-sectional images by SEM (HR-SEM, S-4800, Hitachi) or TEM (FE-TSEM, TITAN G2 ChemiSTEM 80-200, FEI). It can be measured through observation. Alternatively, the thickness of the matrix can be measured by analyzing the electron density difference between adjacent layers using XRR (X'Petr Pro MRD XRD, PANalytical) and inferring thickness oscillation. At this time, the thickness of the matrix may be an average value of thickness values measured at various points on the surface when the conductive film is observed in the normal direction to the surface. The upper limit of the thickness of the matrix resin is not particularly limited, but may be, for example, 200 nm or less, 150 nm or less, or 100 nm or less, and more specifically, 90 nm or less, 85 nm or less, 80 nm or less, 75 nm or less, 70 nm or less. It may be less than or equal to 65 nm, less than or equal to 60 nm or less than or equal to 55 nm.

In one example, the index matching layer having the above configuration may have a refractive index in the range of 1.45 to 1.8.

In one example, the conductive film may further include a substrate. When the conductive film further includes a substrate, the conductive film may sequentially include a substrate, an index matching layer, and a conductive layer. In this case, the surface S of the index matching layer may be a surface facing the conductive layer or a surface directly in contact with one surface of the conductive layer.

The type of substrate is not particularly limited. For example, the base material may be polyester-based resin, acetate-based resin, polyether-based resin, polycarbonate-based resin, poly(meth)acrylic resin, polystyrene-based resin, polyolefin-based resin, polyimide-based resin, polyamide-based resin. , polyvinyl chloride-based resin, polyacetal-based resin, polyvinylidene chloride-based resin, or polyphenylene sulfide-based resin. More specifically, COP (cyclic olefin polymer) or COC (cyclic olefin copolymer) may be used as the polyolefin resin.

The thickness of the base layer is also not particularly limited, and may be, for example, 1 ㎛ or more, specifically 3 to 300 ㎛.

In one example, the conductive layer may be located directly on one side of the index matching layer. That is, the conductive layer may be formed directly on the surface (S) of the index matching layer. In this case, all or part of the particles (P) protrude outside the matrix at the interface between the index matching layer and the conductive layer, and the index matching layer maintains a predetermined surface roughness provided by the particles (P1). You can have it.

The conductive film may further include known elements. For example, an anchor layer, a dielectric layer, an adhesive layer, or an adhesive layer may be included, but are not limited thereto.

In one example, the conductive film may further include a hard coating layer. The hard coating layer refers to a layer that can provide strength to the film.

The hard coating layer may include a curable resin. Although not particularly limited, examples of the curable resin include polyester-based (meth)acrylate-based resin, melamine-based resin, alkyd-based resin, urethane-based resin, olefin-based resin, amide-based resin, cellulose-based resin, silicone-based resin, Epoxy resins, etc. may be used.

In one example, the hard coating layer may include the same resin component or compound as the matrix component of the index matching layer mentioned above.

The thickness of the hard coating layer is not particularly limited, but may range from 0.5 to 10 ㎛, for example. Appropriate strength can be provided within the above range.

In one example, the conductive film may have a resistance change rate of 15% or less according to Equation 1 below.

<Equation 1>

Rate of change of resistance = 100 x {(R2-R1)/R1}

At this time, R1 is the resistance of the conductive film measured at room temperature, and R2 is the resistance measured after storage at 85°C and 85 RH% for 120 hours. At this time, room temperature is the temperature in a state where the temperature is not particularly heated or reduced, for example. For example, it may mean a temperature in the range of 18 to 28°C, more specifically, a temperature of about 23°C. Resistance R1 and R2 can be measured according to the method described in the Examples below.

Satisfying the above resistance change rate means that the conductive film has excellent high temperature/high humidity durability.

In another example related to this application, this application relates to a method of making the conductive film described above. Specifically, the method relates to a method of manufacturing a conductive film using a roll-to-roll process. At this time, as is well known, roll-to-roll refers to a method of forming a laminate using winding and unwinding of a film. The type of roll-to-roll equipment used in the roll-to-roll process is not particularly limited, and for example, metal rolls containing stainless steel, copper (Cu), or aluminum (Al) may include.

The specific structure of the conductive film is the same as described above.

The method includes unwinding an index matching layer comprising a matrix (M) and particles (P) and having a surface (S) on which the particles (P) protrude from roll-to-roll equipment. ; And it may include forming a conductive layer on the unwound index matching layer by a deposition method. The deposition method and detailed process for forming the conductive layer are not particularly limited. For example, a conductive layer containing the transparent conductive oxides listed above may be formed by vacuum deposition or sputtering.

In one example, the conductive layer may be formed directly on one side of the index matching layer. Specifically, the conductive layer may be formed on the surface S having surface roughness imparted by particles existing protruding outside the matrix.

In another example related to this application, this application relates to the use of a conductive film. For example, the conductive film can be used in display devices such as OLED (Organic Light Emitting Diode), PDP (Plasma Display Panel), or LCD (Liquid Crystal Display), or in touch panels. In addition, the conductive film can be used in all known applications to which a conductive film can be applied.

According to an example of the present application, a conductive film that has excellent electrical properties and transparency and can prevent process defects in the roll-to-roll process can be provided.

Figure 1 schematically shows a conductive film according to an example of the present application.
Figure 2 is a portion of an image used to measure the number of particles per unit area of the index matching layer interface in the examples and comparative examples of this application.
Figure 3 is an image to explain a method of calculating maximum surface roughness.

Hereinafter, the present application will be described in detail through examples. However, the scope of protection of the present application is not limited to the examples described below.

<Evaluation method>

* Particle size distribution of particles (P) in the index matching layer (content of P1 and P2 particles) : The particle size of the particles used was measured with DLS (dynamic light scattering) equipment.

* Maximum surface roughness : The surface roughness was measured for a 5 x 5㎛ surface area using an atomic force microscope (AFM) (tapping mode, PPP-NCHR 10M tip). Specifically, an arbitrary reference point (zero position) is set in the thickness direction for a 5 x 5 ㎛ area selected on the surface (S), and the normal distance (+d ₁ ) and the normal distance (-d) to the matrix lower than the reference point (Rmax = d ₁ - (-d ₂ )) was recorded.

* Static friction coefficient : In general, the friction coefficient of the index matching layer for SUS (stainless steel), the main material of the roll where the film is wound and unwound in the roll-to-roll process, was measured. Specifically, according to the ASTM D1894 method, the SUS substrate was placed on the surface (S) of the index matching layer manufactured in the examples and comparative examples, and the friction coefficient was measured under a load of 200 g using a weight. did. The evaluation results are as follows.

- O (Excellent): Friction coefficient less than 1.0

- X (bad): A point where the friction coefficient exceeds 1.0 is observed.

* Processability (surface deformation): As in the examples and comparative examples, a conductive layer, which is a deposited layer, is formed on the index matching layer while unwinding and moving the laminate using a roll-to-roll process, and the manufactured conductive layer is The presence or absence of surface deformation of the film (or conductive layer) was observed. The evaluation criteria are as follows:

- O (Excellent): No wrinkles or folds observed

- X (defect): Wrinkles or folds are observed

* Resistance change : The conductive films manufactured according to Examples and Comparative Examples were measured using a sheet resistance meter (Loresta HP MCP-T410, Mitsubishi-chemical). Specifically, the 4-probe contact resistance was measured for a 60mm x 60mm size in the center of the conductive layer sample, and the degree of change was calculated. If the resistance change rate according to the formula below was 15% or less, the resistance change durability under high temperature/high humidity was evaluated as excellent (O), and if it exceeded 15%, it was evaluated as poor (X).

Rate of change of resistance = 100 x {(R2-R1)/R1}

At this time, R1 is the resistance of the conductive film measured at room temperature (23°C), and R2 is the resistance measured after storage at 85°C and 85 RH% for 120 hours.

<Examples and Comparative Examples>

Example 1

Formation of hard coating layer

Compared to 100 parts by weight of a mixture of epoxy acrylate and pentaerythritol triacrylate, 60 parts by weight of epoxy acrylate (CN110, Sartomer), 40 parts by weight of pentaerythritol triacrylate (SR444, Sartomer) and a photoinitiator (Irgacure184, basf) A composition for forming a hard coating layer was prepared by mixing 4 parts by weight. Then, the composition was applied to one side of a cycloolefin polymer (ZF16, ZEON) film with a thickness of 40 ㎛ and a refractive index of 1.5 and dried to form a hard coating layer with a refractive index of 1.55 (1 ㎛ thick).

Formation of index matching layer

Compared to 100 parts by weight of the mixture of epoxy acrylate and pentaerythritol triacrylate, 60 parts by weight of epoxy acrylate (CN110, Sartomer), 40 parts by weight of pentaerythritol triacrylate (PETA) (SR444, Sartomer), photoinitiator ( 4 parts by weight of Irgacure184 (Basf Co., Ltd.), 5 parts by weight of silica nanoparticles (MEK-AC5140Z, Nissan Chemicals) satisfying equation 1 above, and 150 parts by weight of zirconia nanoparticles (PCPA-50PGA, Pixelligent) satisfying equation 2 above. A composition for forming an index matching layer was prepared by mixing. Then, the composition was applied to one side of the hard coating layer, dried, and cured with a vacuum UV irradiator to form a layer with a refractive index of 1.68 and a thickness of about 80 nm.

Manufacturing of conductive film

The prepared laminate (cycloolefin film/hard coating layer/index matching layer) was wound on a roll-to-roll equipment. Thereafter, while unwinding and transporting the laminate in roll-to-roll equipment, an ITO layer with a thickness of 25 nm is deposited using a sputtering method in an atmosphere of 5 mTorr consisting of 98.4% argon gas and 1.6% oxygen gas, A conductive film was prepared.

Example 2, Example 3, Comparative Example 1 and Comparative Example 2

As shown in Table 1 below, conductive films were manufactured in the same manner, except that the composition of each Example and Comparative Example was different from Example 1.

The composition and physical property measurement results of the prepared conductive films are shown in Table 1 and Table 2, respectively.

[Table 1]

[Table 2]

Claims (16)

conductive layer; and
An index matching layer located on at least one surface of the conductive layer, including a matrix (M) and particles (P), and having a surface (S) on which the particles (P) protrude. It's a film,
The matrix forms a continuous phase in the index matching layer, and the particles exist in a dispersed state within the continuous phase,
The index matching layer is a conductive film containing particles (P1) satisfying the following relational equation 1 in the range of 0.5 to 15 parts by weight, based on 100 parts by weight of the resin component for matrix formation:
[Relationship 1]
(D _P1 /T _M ) > 1
(In the above relational equation 1, D _P1 refers to the particle size of the particles P1 included in the index matching layer, and T _M refers to the thickness of the matrix of the index matching layer.) The conductive film according to claim 1, further comprising 200 parts by weight or less of particles (P2) satisfying the following equation 2:
[Relational Expression 2]
(D _P2 /T _M ) ≤ 1
(In the above relational equation 2, D _P2 refers to the particle size of the particles (P2) included in the index matching layer, and T _M refers to the thickness of the matrix of the index matching layer.) The conductive film according to claim 1, wherein the maximum surface roughness (Rmax) of the surface (S) is within the range of 15 to 100 nm. The conductive film according to claim 1, wherein the surface (S) faces one side of the conductive layer or is in direct contact with one side of the conductive layer. The conductive film according to claim 1, wherein the number of particles observed on the surface (S) is in the range of 0.2 to 3.0 particles/㎛ ² . The conductive film according to claim 1, wherein the surface (S) has a coefficient of static friction of 1.0 or less. The conductive film of claim 1, wherein the index matching layer has a refractive index in the range of 1.45 to 1.80. The conductive film of claim 1, wherein the matrix includes a silicone resin, an acrylic resin, an epoxy resin, or a urethane resin. The method of claim 1, wherein the particles are NaF, MgF ₂ , CaF ₂ , BaF ₂ , SiO ₂ , CeF ₃ , Al ₂ O ₃ , ZrO ₂ , TiO ₂ , ZnS, ZnSe, Ta ₂ O ₅ or alkoxysilane particles. A conductive film comprising: The method of claim 1, wherein the conductive layer is made of indium tin oxide (ITO), indium oxide (In ₂ O ₃ ), indium galium oxide (IGO), fluor doped tin oxide (FTO), aluminum doped zinc oxide (AZO), and GZO. Contains one or more selected from (Galium doped Zinc Oxide), ATO (Antimony doped Tin Oxide), IZO (Indium doped Zinc Oxide), NTO (Niobium doped Titanium Oxide), ZnO (zink oxide), and CTO (Cesium Tungsten Oxide) conductive film. The conductive film of claim 1, wherein the conductive layer has a surface resistance in the range of 40 to 500 Ω/□. The conductive film of claim 1, further comprising a substrate, and sequentially including the substrate, the index matching layer, and the conductive layer. A method of manufacturing a conductive film according to claim 1,
Unwinding an index matching layer including a matrix (M) and particles (P) and having a surface (S) on which the particles (P) protrude from roll-to-roll equipment; and
A method comprising forming a conductive layer on the unwound index matching layer by a deposition method. 14. The method of claim 13, wherein the conductive layer is formed on the surface (S). A touch panel comprising the conductive film according to claim 1. A display device comprising the conductive film according to claim 1.