Heat sink, its manufacturing method and image display device including the same

Abstract

To provide: a heat sink including metal foil and a corrosion-resistant passivation film that is formed on at least one side of the metal foil, the corrosion-resistant passivation film being formed from a photosensitive resin composition; and a method of manufacturing the same.SOLUTION: A heat sink has a corrosion-resistant passivation film formed from a photosensitive resin composition, and thus not only has excellent corrosion resistance while exhibiting a heat-dissipating effect, but also can maintain a beautiful appearance property specific to metal. Further, adhesion between metal foil and the corrosion-resistant passivation film can be secured, and patterning of the corrosion-resistant passivation film can be performed as required.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heat sink, a method for manufacturing the same, and an image display device including the same. [Background technology]

[0002] In recent years, as image display devices have become larger and higher resolution, the amount of heat generated per unit area of ​​components has increased dramatically, and as a result, heat dissipation issues for related components have become a growing concern. In particular, if heat generated from devices used in OLEDs and displays cannot be effectively dissipated, it can shorten the lifespan of the product.

[0003] Therefore, a method of using a heat sink made of a metal material has been proposed to ensure heat dissipation from the image display device.

[0004] However, although metal materials are excellent at dissipating heat energy due to their high thermal conductivity, they have the problem of being vulnerable to corrosion.

[0005] Therefore, various methods have been proposed to ensure the corrosion resistance of metal materials.

[0006] For example, Korean Patent Registration No. 10-1532201 discloses a corrosion-resistant coating composition for metals containing 35 to 55 parts by weight of a moisture-curing polyurethane resin, 15 to 25 parts by weight of a polymer-coated aluminum paste, 1 to 10 parts by weight of an additive, and 25 to 35 parts by weight of a hydrocarbon solvent and an acetate-based solvent.

[0007] However, the corrosion-resistant coating composition has a problem in that it is difficult to maintain the beautiful appearance characteristic of metal when the heat sink is located at the outermost part. Therefore, there is a demand for the development of a heat sink made of a metal material that not only has excellent corrosion resistance but also maintains the beautiful appearance characteristic of metal. Summary of the Invention [Problem to be solved by the invention]

[0008] An object of the present invention is to provide a heat sink that not only has excellent corrosion resistance but also maintains the beautiful appearance characteristic of metal.

[0009] Another object of the present invention is to provide a method for manufacturing the heat sink.

[0010] It is still another object of the present invention to provide an image display device including the heat sink. [Means for solving the problem]

[0011] On the other hand, the present invention provides a metal foil, and a corrosion-resistant passivation film formed on at least one surface of the metal foil; The corrosion-resistant passivation film provides a heat sink formed from a photosensitive resin composition.

[0012] In one embodiment of the present invention, the metal foil may comprise a metal selected from the group consisting of copper (Cu), aluminum (Al), nickel (Ni), magnesium (Mg), zinc (Zn), tantalum (Ta), titanium (Ti), tungsten (W), molybdenum (Mo), tin (Sn), and indium (In), or an alloy thereof.

[0013] In one embodiment of the present invention, the metal foil may have a thickness of 70 to 150 μm.

[0014] In one embodiment of the present invention, the photosensitive resin composition includes an alkali-soluble resin, a photopolymerizable compound, a photopolymerization initiator, and a solvent, and the alkali-soluble resin may include an alkali-soluble resin including a repeating unit having an epoxy group.

[0015] In one embodiment of the present invention, the alkali-soluble resin may include a first alkali-soluble resin including a repeating unit having an epoxy group-containing crosslinked ring group, and a second alkali-soluble resin including a repeating unit having an aromatic ring group.

[0016] In one embodiment of the present invention, the corrosion-resistant passivation film may have a visible light transmittance of 89% or more.

[0017] In one embodiment of the present invention, the corrosion-resistant passivation film may have a thickness of 1 to 5 μm.

[0018] In one embodiment of the present invention, the corrosion-resistant passivation film may be patterned.

[0019] On the other hand, the present invention A step of applying a photosensitive resin composition to at least one surface of a metal foil to obtain a coating film; drying the coating; photocuring the dried coating; and The photocured coating film is post-baked to form a corrosion-resistant passivation film.

[0020] In the photo-curing step, the manufacturing method according to an embodiment of the present invention may include performing light irradiation using a mask, and developing the photo-cured coating film after the photo-curing step.

[0021] In one embodiment of the present invention, the photosensitive resin composition includes an alkali-soluble resin, a photopolymerizable compound, a photopolymerization initiator, and a solvent, and the alkali-soluble resin may include a first alkali-soluble resin including a repeating unit having an epoxy group-containing crosslinked ring group, and a second alkali-soluble resin including a repeating unit having an aromatic ring group.

[0022] In one embodiment of the present invention, the post-baking may be performed at 90 to 150°C.

[0023] On the other hand, the present invention provides an image display device including the heat sink. [Effects of the Invention]

[0024] The heat sink of the present invention has a corrosion-resistant passivation film formed from a photosensitive resin composition, which not only provides excellent corrosion resistance while exhibiting heat dissipation effects, but also maintains the beautiful appearance characteristic of metal. Furthermore, the heat sink of the present invention can ensure adhesion between the metal foil and the corrosion-resistant passivation film, and the corrosion-resistant passivation film can be patterned as needed. [Brief explanation of the drawings]

[0025] [Figure 1] 1 shows a heat sink according to one embodiment of the present invention. [Figure 2] 1 is a photograph of the surface of a copper foil substrate before being left in salt water. [Figure 3] 1 is a photograph of the surface of a copper foil substrate on which a corrosion-resistant passivation film has not been formed after exposure to salt water. [Figure 4] 1 is a photograph of the surface of a copper foil substrate of a heat sink according to the present invention after being left in salt water. [Figure 5] 1 shows the measurement results of the visible light transmittance of the corrosion-resistant passivation film in the wavelength range of 360 to 740 nm. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention will now be described in more detail.

[0027] One embodiment of the present invention comprises a metal foil, and a corrosion-resistant passivation film formed on at least one surface of the metal foil; The corrosion-resistant passivation film relates to a heat sink formed from a photosensitive resin composition.

[0028] The heat sink according to one embodiment of the present invention has a corrosion-resistant passivation film formed from a photosensitive resin composition, which not only provides excellent corrosion resistance but also maintains the beautiful appearance characteristic of metal. Furthermore, the heat sink according to one embodiment of the present invention can ensure adhesion between the metal foil and the corrosion-resistant passivation film, and the corrosion-resistant passivation film can be patterned as needed.

[0029] Thermal resistance is a numerical value that indicates the property of impeding heat transfer, and is expressed as thickness / thermal conductivity. The heat sink of the present invention can reduce the thermal resistance of the heat sink by using a metal material with good thermal conductivity, and can minimize the increase in thermal resistance by forming a thin corrosion-resistant passivation film, resulting in excellent heat dissipation performance.

[0030] A heat sink according to one embodiment of the present invention may have a corrosion-resistant passivation film laminated on at least one side of the metal foil, but preferably has a structure in which a first corrosion-resistant passivation film 201 and a second corrosion-resistant passivation film 202 are laminated on both sides of the metal foil 100, as shown in Figure 1.

[0031] In one embodiment of the present invention, the metal foil 100 may include a metal selected from the group consisting of copper (Cu), aluminum (Al), nickel (Ni), magnesium (Mg), zinc (Zn), tantalum (Ta), titanium (Ti), tungsten (W), molybdenum (Mo), tin (Sn), and indium (In) or an alloy thereof, and may be, but is not limited to, a copper thin film, i.e., a copper foil, which has excellent electrical conductivity and is inexpensive. The metal foil may be a layer formed by electrolysis or a layer formed by rolling.

[0032] For example, the metal foil may be a copper alloy foil containing Cu in an amount of 90±9 wt %, for example 97 wt %, with the remainder containing the other metals mentioned above. The thickness of the metal foil is not particularly limited in the present invention, but may be preferably 70 to 150 μm. If the thickness of the metal foil is less than the above range, it may be difficult to ensure sufficient heat dissipation characteristics, and if it exceeds the above range, the thickness and weight of the device to which the heat sink is applied may increase, or the increased thickness may actually hinder heat dissipation. In one embodiment of the present invention, the first corrosion-resistant passivation film 201 and the second corrosion-resistant passivation film 202 are each independently formed from a photosensitive resin composition.

[0033] The photosensitive resin composition may contain an alkali-soluble resin, a photopolymerizable compound, a photopolymerization initiator, and a solvent.

[0034] The alkali-soluble resin is a component that is generally reactive to light or heat and imparts solubility to an alkali developer used in the development process for forming a pattern.

[0035] The alkali-soluble resin may include an alkali-soluble resin containing a repeating unit having an epoxy group from the viewpoints of corrosion resistance, transmittance, and adhesion, and preferably includes a first alkali-soluble resin containing a repeating unit having an epoxy group-containing crosslinked ring group and a second alkali-soluble resin containing a repeating unit having an aromatic ring group.

[0036] The first alkali-soluble resin contains a repeating unit having an epoxy group-containing crosslinked ring group.

[0037] The repeating unit having an epoxy group-containing crosslinked ring group may be introduced by an ethylenically unsaturated monomer having an epoxy group-containing crosslinked ring group, for example, a (meth)acrylate monomer having an epoxy group-containing crosslinked ring group.

[0038] The first alkali-soluble resin may further contain a repeating unit having another epoxy group-containing functional group in addition to the repeating unit having an epoxy group-containing crosslinked ring group.

[0039] The repeating unit having another epoxy group-containing functional group may be introduced by an ethylenically unsaturated monomer having an aliphatic or alicyclic epoxy group-containing functional group, for example, a (meth)acrylate monomer having an aliphatic or alicyclic epoxy group-containing functional group.

[0040] The first alkali-soluble resin contains a carboxyl group-containing repeating unit to ensure solubility in an alkaline developer.

[0041] The carboxyl group-containing repeating unit may be introduced by an ethylenically unsaturated monomer having a carboxyl group. Specific examples of the ethylenically unsaturated monomer having a carboxyl group include monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, 2-(meth)acryloyloxyethylhexahydrophthalate, 2-(meth)acryloyloxyethylphthalate, and 2-(meth)acryloyloxyethyl succinate; dicarboxylic acids such as fumaric acid, mesaconic acid, and itaconic acid; and anhydrides of these dicarboxylic acids; and mono(meth)acrylates of polymers having a carboxyl group and a hydroxyl group at both ends, such as ω-carboxypolycaprolactone mono(meth)acrylate, among which acrylic acid and methacrylic acid are preferred.

[0042] Preferably, the first alkali-soluble resin may contain a repeating unit represented by the following chemical formula 1:

[0043] [ka]

[0044] In the above formula, R1, R2, and R3 are each independently a hydrogen atom or a methyl group; R4 is a structure derived from a monomer selected from the group consisting of the following formulas (1) to (3):

[0045] [ka]

[0046] R5 is a structure derived from a monomer selected from the group consisting of the following formulas (4) to (12):

[0047] [ka]

[0048] R6 is a structure derived from an ethylenically unsaturated monomer having a carboxyl group, a indicates 20 to 70 mol%, b indicates 20 to 60 mol%, and c indicates 5 to 30 mol%.

[0049] A preferred example of the repeating unit represented by Chemical Formula 1 is a repeating unit represented by Chemical Formula 1-1 below.

[0050] [ka]

[0051] In the above formula, R1, R2, and R3 are each independently hydrogen or a methyl group; a indicates 20 to 70 mol%, b indicates 20 to 60 mol%, and c indicates 5 to 30 mol%.

[0052] The second alkali-soluble resin contains a repeating unit having an aromatic ring group.

[0053] The repeating unit having an aromatic ring group may be introduced by an ethylenically unsaturated monomer having an aromatic ring group, for example, a vinyl monomer having an aromatic ring group and / or a (meth)acrylate monomer having an aromatic ring group.

[0054] The second alkali-soluble resin may further contain a repeating unit having an epoxy group-containing functional group other than the repeating unit having an epoxy group-free crosslinked ring group and the repeating unit having an epoxy group-containing crosslinked ring group.

[0055] The repeating unit having an epoxy group-free crosslinked ring group may be introduced by an ethylenically unsaturated monomer having an epoxy group-free crosslinked ring group, for example, a (meth)acrylate monomer having an epoxy group-free crosslinked ring group.

[0056] A repeating unit having an epoxy group-containing functional group other than the repeating unit having an epoxy group-containing crosslinked ring group may be introduced by an ethylenically unsaturated monomer having an aliphatic or alicyclic epoxy group-containing functional group, for example, a (meth)acrylate having an aliphatic or alicyclic epoxy group-containing functional group.

[0057] The second alkali-soluble resin contains a carboxyl group-containing repeating unit to ensure solubility in an alkali developer.

[0058] The carboxyl group-containing repeating unit is as described above for the first alkali-soluble resin.

[0059] Preferably, the second alkali-soluble resin may contain a repeating unit represented by the following chemical formula 2.

[0060] [ka]

[0061] In the above formula, R7, R8, R9, and R 10 are each independently a hydrogen atom or a methyl group, R 11 is a structure derived from a monomer selected from the group consisting of the following formulas (13) to (18), and n is an integer of 1 to 5:

[0062] [ka]

[0063] R 12is a structure derived from a monomer selected from the group consisting of the following formulas (19) to (23):

[0064] [ka]

[0065] R 13 is a structure derived from an ethylenically unsaturated monomer having a carboxyl group, R 14 is a structure derived from a monomer selected from the group consisting of the following formulas (24) to (32):

[0066] [ka]

[0067] d indicates 10 to 20 mol%, e indicates 10 to 30 mol%, f indicates 10 to 30 mol%, and g indicates 30 to 60 mol%.

[0068] A preferred example of the repeating unit represented by the above chemical formula 2 is a repeating unit represented by the following chemical formula 2-1.

[0069] [ka]

[0070] In the above formula, R7, R8, R9, and R 10 are each independently a hydrogen atom or a methyl group; d indicates 10 to 20 mol%, e indicates 10 to 30 mol%, f indicates 10 to 30 mol%, and g indicates 30 to 60 mol%.

[0071] In the present invention, "(meth)acryl-" refers to "methacryl-", "acryl-", or both.

[0072] In the present invention, the repeating units represented by Chemical Formula 1 and Chemical Formula 2 should not be construed as being limited to those represented by Chemical Formula 1 and Chemical Formula 2, and the sub-repeating units in parentheses may be freely located at any position in the chain within the specified mol% range. That is, although the parentheses in Chemical Formula 1 and Chemical Formula 2 are represented as a single block to indicate mol%, the sub-repeating units may be located in a block or separately within the corresponding resin without any restrictions.

[0073] In the present invention, the monomers represented by the formulas (1) to (32) include isomers of the monomers, and when the monomers represented by each formula have isomers, the monomer represented by the corresponding formula means a representative chemical formula including the isomers.

[0074] The weight average molecular weight of the first alkali-soluble resin is preferably 6000 to 12000. Within this molecular weight range, excellent corrosion resistance, transmittance, and adhesion can be exhibited.

[0075] The weight average molecular weight of the second alkali-soluble resin is preferably 20,000 to 30,000. Within this molecular weight range, excellent corrosion resistance, transmittance, and adhesion can be exhibited.

[0076] The mixing weight ratio of the first alkali-soluble resin to the second alkali-soluble resin may be 50:50 to 90:10, and preferably 70:30 to 80:20. If the content of the first alkali-soluble resin is less than the lower limit, low-temperature curing properties may be reduced, and resolution may be reduced due to sagging at the step at the pattern boundary, or residue may be generated after development. On the other hand, if the content is greater than the upper limit, pattern formability may be reduced, and storage stability may be reduced, resulting in performance degradation after long-term storage.

[0077] The first alkali-soluble resin and the second alkali-soluble resin may each independently further contain repeating units formed from other monomers known in the art in addition to the repeating units described above.

[0078] The other monomer is not particularly limited, and examples thereof include N-substituted maleimide compounds such as N-cyclohexylmaleimide, N-benzylmaleimide, N-phenylmaleimide, No-hydroxyphenylmaleimide, Nm-hydroxyphenylmaleimide, Np-hydroxyphenylmaleimide, No-methylphenylmaleimide, Nm-methylphenylmaleimide, Np-methylphenylmaleimide, No-methoxyphenylmaleimide, Nm-methoxyphenylmaleimide, and Np-methoxyphenylmaleimide; methyl(meth)acrylate, ethyl(meth)acrylate, n-propyl(meth)acrylate, i-propyl(meth)acrylate, n-butyl(meth)acrylate, i-butyl(meth)acrylate, s Examples of suitable oxetane compounds include, but are not limited to, alkyl (meth)acrylates such as ec-butyl (meth)acrylate; alicyclic (meth)acrylates such as cyclopentyl (meth)acrylate, 2-methylcyclohexyl (meth)acrylate, and 2-dicyclopentanyloxyethyl (meth)acrylate; and unsaturated oxetane compounds such as 3-(methacryloyloxymethyl)oxetane, 3-(methacryloyloxymethyl)-3-ethyloxetane, 3-(methacryloyloxymethyl)-2-trifluoromethyloxetane, 3-(methacryloyloxymethyl)-2-phenyloxetane, 2-(methacryloyloxymethyl)oxetane, and 2-(methacryloyloxymethyl)-4-trifluoromethyloxetane. These compounds may be used alone or in combination.

[0079] The first alkali-soluble resin and the second alkali-soluble resin preferably each have an acid value in the range of 20 to 200 (KOH mg / g). When the acid value is in this range, excellent developability and stability over time can be exhibited.

[0080] The content of the alkali-soluble resin is not particularly limited, but may be, for example, 10 to 90 parts by weight, preferably 25 to 70 parts by weight, based on 100 parts by weight of the total solid content in the photosensitive resin composition. When the content is within this range, the solubility in the developer is sufficient, allowing the formation of a corrosion-resistant passivation film with excellent developability and mechanical properties.

[0081] The photopolymerizable compound increases the crosslink density during the manufacturing process and strengthens the mechanical properties of the corrosion-resistant passivation film.

[0082] The photopolymerizable compound is a compound that can be polymerized by the action of light and a photopolymerization initiator described later, and examples thereof include monofunctional photopolymerizable compounds, bifunctional photopolymerizable compounds, and trifunctional or higher polyfunctional photopolymerizable compounds.

[0083] Specific examples of the monofunctional photopolymerizable compound include nonylphenyl carbitol acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-ethylhexyl carbitol acrylate, 2-hydroxyethyl acrylate, and N-vinylpyrrolidone, and commercially available products thereof include Aronix M-101 (Toagosei), KAYARAD TC-110S (Nippon Kayaku), and Viscoat 158 ​​(Osaka Organic Chemical Industry).

[0084] Specific examples of the bifunctional photopolymerizable compound include 1,6-hexanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, bis(acryloyloxyethyl) ether of bisphenol A, and 3-methylpentanediol di(meth)acrylate. Commercially available products include Aronix M-210, M-1100, and M-1200 (Toagosei), KAYARAD HDDA (Nippon Kayaku), Viscoat 260 (Osaka Organic Chemical Industry), AH-600, AT-600, and UA-306H (Kyoeisha Chemical Co., Ltd.).

[0085] Specific examples of the trifunctional or higher polyfunctional photopolymerizable compound include trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethoxylated dipentaerythritol hexa(meth)acrylate, and propoxylated dipentaerythritol hexa(meth)acrylate. Commercially available products include NK ESTER ATM-4E (Shin-Nakamura Chemical Co., Ltd.), NK ESTER Examples include A-DPH-12E (Shin-Nakamura Chemical Co., Ltd.), A-9570 (Shin-Nakamura Chemical Co., Ltd.), Aronix M-309, M-520 (Toagosei), KAYARAD TMPTA, KAYARAD DPHA, and KAYARAD DPHA-40H (Nippon Kayaku).

[0086] The photopolymerizable compounds exemplified above may be used alone or in combination of two or more.

[0087] The content of the photopolymerizable compound is not particularly limited, but is preferably 10 to 90 parts by weight, more preferably 30 to 80 parts by weight, relative to 100 parts by weight of the total solid content in the photosensitive resin composition. When the photopolymerizable compound is contained in the above content range, excellent durability can be obtained and developability can be improved.

[0088] The photopolymerization initiator can be any type that can polymerize the photopolymerizable compound, and is not particularly limited. In particular, from the viewpoints of polymerization characteristics, initiation efficiency, absorption wavelength, availability, cost, etc., it is preferable to use one or more compounds selected from the group consisting of acetophenone-based compounds, benzophenone-based compounds, triazine-based compounds, biimidazole-based compounds, oxime-based compounds, and thioxanthone-based compounds as the photopolymerization initiator.

[0089] Specific examples of the acetophenone-based compound include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl ketal, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propan-1-one, and 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)butan-1-one.

[0090] Examples of the benzophenone compounds include benzophenone, methyl 0-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone, and 2,4,6-trimethylbenzophenone.

[0091] Specific examples of the triazine-based compound include 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxynaphthyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-piperonyl-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5-triazine, and 2,4-bis(trichloromethyl)-6- [2-(5-methylfuran-2-yl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)ethenyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)ethenyl]-1,3,5-triazine, and the like.

[0092] Specific examples of the biimidazole-based compound include 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(2,3-dichlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetra(alkoxyphenyl)biimidazole, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetra(trialkoxyphenyl)biimidazole, 2,2-bis(2,6-dichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole, and biimidazole compounds in which the phenyl groups at the 4,4',5,5' positions are substituted with carboalkoxy groups. Of these, 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(2,3-dichlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, and 2,2-bis(2,6-dichlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole are preferably used.

[0093] Specific examples of the oxime compounds include o-ethoxycarbonyl-α-oximino-1-phenylpropan-1-one, 1,2-octanedione, -1-(4-phenylthio)phenyl, -2-(o-benzoyloxime), ethanone, -1-(9-ethyl)-6-(2-methylbenzoyl)carbazol-3-yl, and 1-(o-acetyloxime). Commercially available products include CGI-124 (Ciba-Geigy), CGI-224 (Ciba-Geigy), Irgacure OXE-01 (BASF), Irgacure OXE-02 (BASF), N-1919 (ADEKA), and NCI-831 (ADEKA).

[0094] Examples of the thioxanthone compounds include 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, and 1-chloro-4-propoxythioxanthone.

[0095] In addition, the photopolymerization initiator may further contain a photopolymerization initiation aid to improve the sensitivity of the photosensitive resin composition. By including the photopolymerization initiation aid, the photosensitive resin composition can further increase its sensitivity and improve productivity.

[0096] As the photopolymerization initiation aid, for example, one or more compounds selected from the group consisting of amine compounds, carboxylic acid compounds, and organic sulfur compounds having a thiol group may be preferably used.

[0097] Specific examples of the amine compound that can be used include aliphatic amine compounds such as triethanolamine, methyldiethanolamine, and triisopropanolamine, and aromatic amine compounds such as methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2-dimethylaminoethyl benzoate, N,N-dimethyl-p-toluidine, 4,4'-bis(dimethylamino)benzophenone (commonly known as Michler's ketone), and 4,4'-bis(diethylamino)benzophenone, with aromatic amine compounds being particularly preferred.

[0098] The carboxylic acid compound is preferably an aromatic heteroacetic acid, and specific examples thereof include phenylthioacetic acid, methylphenylthioacetic acid, ethylphenylthioacetic acid, methylethylphenylthioacetic acid, dimethylphenylthioacetic acid, methoxyphenylthioacetic acid, dimethoxyphenylthioacetic acid, chlorophenylthioacetic acid, dichlorophenylthioacetic acid, N-phenylglycine, phenoxyacetic acid, naphthylthioacetic acid, N-naphthylglycine, and naphthoxyacetic acid.

[0099] Specific examples of the organic sulfur compound having a thiol group include 2-mercaptobenzothiazole, 1,4-bis(3-mercaptobutyryloxy)butane, 1,3,5-tris(3-mercaptobutyloxyethyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, trimethylolpropane tris(3-mercaptopropionate), pentaerythritol tetrakis(3-mercaptobutyrate), pentaerythritol tetrakis(3-mercaptopropionate), dipentaerythritol hexakis(3-mercaptopropionate), and tetraethylene glycol bis(3-mercaptopropionate).

[0100] The photopolymerization initiator may be contained in an amount of 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight, relative to 100 parts by weight of the total solid content in the photosensitive resin composition. When the photopolymerization initiator is contained within this range, the photosensitive resin composition becomes highly sensitive and the exposure time is shortened, thereby improving productivity and maintaining high resolution.

[0101] When the photopolymerization initiation aid is further used, the photopolymerization initiation aid may be contained in an amount of 0.1 to 10 parts by weight, preferably 0.1 to 5 parts by weight, relative to 100 parts by weight of the total solid content in the photosensitive resin composition. When the amount of the photopolymerization initiation aid used is within the above range, the sensitivity of the photosensitive resin composition may be further increased, and the productivity of the photocured film formed using the composition may be improved.

[0102] The photosensitive resin composition may further contain a polyfunctional thiol compound.

[0103] The polyfunctional thiol compound is a tri- or higher functional thiol compound, which improves the crosslink density, thereby improving the durability of the corrosion-resistant passivation film and its adhesion to the metal substrate, and also prevents yellowing at high temperatures.

[0104] The polyfunctional thiol compound is not particularly limited as long as it is a trifunctional or higher functional thiol compound that can be used in a photosensitive resin composition, and is preferably a tetrafunctional or higher functional thiol compound. For example, the polyfunctional thiol compound may be a compound represented by the following chemical formula 3:

[0105] [ka]

[0106] In the above formula, Z1 is a methylene group, or a linear or branched alkylene or alkylmethylene group having 2 to 10 carbon atoms; Y is absent, —CO—, —O—CO—, or —NHCO—; X is an n-valent hydrocarbon group having 2 to 70 carbon atoms which may have one or more ether bonds, or a trivalent group represented by the following chemical formula 4: n is an integer from 3 to 10,

[0107] [ka]

[0108] In the above formula, Z2, Z3, and Z4 are each independently a methylene group or an alkylene group having 2 to 6 carbon atoms; "*" indicates a bond.

[0109] The content of the polyfunctional thiol compound is not particularly limited, but may be, for example, in the range of 0.1 to 15 parts by weight, preferably 1 to 10 parts by weight, relative to 100 parts by weight of the alkali-soluble resin. When the polyfunctional thiol compound is contained in the above content range, excellent low-temperature curing performance can be exhibited.

[0110] In addition to the above-mentioned components, the photosensitive resin composition may contain additives such as other polymer compounds, curing agents, surfactants, adhesion promoters, antioxidants, ultraviolet absorbers, and anti-aggregation agents, as needed by those skilled in the art, within the scope of the present invention.

[0111] The viscosity of the photosensitive resin composition may be 20 cP or less, for example, 5 to 20 cP. If the viscosity of the photosensitive resin composition exceeds 20 cP, the coating properties may be reduced, resulting in insufficient flatness of the coating surface. In particular, if there is foreign matter on the surface of the underlying substrate, steps at the location of the foreign matter may increase.

[0112] The corrosion-resistant passivation film may have a visible light transmittance of 89% or more, preferably 95% or more.

[0113] The visible light transmittance means the transmittance over the entire wavelength range of visible light, for example, in the range of 360 nm to 740 nm.

[0114] If the visible light transmittance of the corrosion-resistant passivation film is less than 89%, it may be difficult to maintain the beautiful appearance characteristic of metal.

[0115] The thickness of the corrosion-resistant passivation film may be 1 to 5 μm, preferably 1.5 to 2.5 μm. If the thickness of the corrosion-resistant passivation film is less than 1 μm, the roughness of the metal foil may result in poor coating, external moisture may penetrate, or the corrosion resistance may be reduced due to an insufficient film thickness. If the thickness exceeds 5 μm, the curing time may increase, reducing productivity and heat dissipation performance may be reduced.

[0116] The adhesion of the corrosion-resistant passivation film to the metal foil may be at level 5B according to ASTM D3359.

[0117] If the adhesion strength of the corrosion-resistant passivation film to the metal foil is less than 5B, corrosion resistance may decrease, external moisture may penetrate, or film lift-off defects may occur in the subsequent processing steps.

[0118] The corrosion-resistant passivation film is formed from a photosensitive resin composition and may be patterned as necessary, using a conventional photolithography method.

[0119] One embodiment of the present invention relates to a method for manufacturing the heat sink.

[0120] A method for manufacturing a heat sink according to one embodiment of the present invention includes the steps of: A step of applying a photosensitive resin composition to at least one surface of a metal foil to obtain a coating film; drying the coating; photocuring the dried coating; and The photocured coating is post-baked to form a corrosion-resistant passivation layer.

[0121] The constituent components, thickness, physical properties, etc. of the metal foil and the corrosion-resistant passivation film are the same as those described for the heat sink.

[0122] Examples of methods for applying the photosensitive resin composition include spin coating, slot die coating, gravure coating, inkjet printing, roll coating, and slit and spin coating.

[0123] The drying (pre-baking) of the coating film is a process for volatilizing the solvent in the primary drying and then adhering the photocuring reaction sites to facilitate smooth photocuring, which contributes to ensuring the density of the photocured coating film. This process may be carried out at 90 to 110°C for 1 to 10 minutes, preferably at 100°C for 2 to 5 minutes.

[0124] The pre-baking is carried out by heating in an oven, a hot plate, or the like.

[0125] The photocuring may be carried out by light irradiation.

[0126] When the corrosion-resistant passivation film is patterned, the photo-curing step may include irradiating the film with light using a mask, and developing the photo-cured film after the photo-curing step.

[0127] At this time, it is preferable to use a device such as a mask aligner or a stepper so that the entire exposed area is uniformly irradiated with parallel light and the mask and substrate are accurately aligned. When ultraviolet light is irradiated, the irradiated area is cured.

[0128] The ultraviolet rays may be g-rays (wavelength: 436 nm), h-rays, i-rays (wavelength: 365 nm), etc., and in particular i-rays (wavelength: 365 nm). The irradiation dose of ultraviolet rays may be appropriately selected as needed, for example, 70 to 200 mJ / cm. 2 , preferably 100 to 150 mJ / cm 2 It may be.

[0129] The development is carried out for the purpose of removing the photosensitive resin composition from the unexposed areas, and a desired pattern is formed by the development.

[0130] The developer suitable for the development may be, for example, an aqueous solution of an alkali metal or alkaline earth metal hydroxide, etc. In particular, the development may be carried out at room temperature for 60 to 120 seconds using an alkaline aqueous solution containing KOH at a concentration of 0.01 to 0.1 wt %, for example, 0.045 wt %.

[0131] The developing method may be any of a liquid addition method, a dipping method, a spray method, etc. Furthermore, the substrate may be tilted at any angle during development.

[0132] After development, the film is washed with water and post-baked.

[0133] Post-baking is performed to increase the degree of hardening of the patterned film and to enhance the reflow of the taper angle of the pattern, and is carried out by heat treatment at 90 to 150°C, preferably 90 to 120°C, for 20 to 30 minutes. When high reliability is required, the post-baking temperature can be increased to 200°C for over-hardening, thereby further increasing the adhesion and hardening degree.

[0134] The post-baking is carried out using an oven, a hot plate or the like, in the same manner as the pre-baking.

[0135] By carrying out the post-baking at a relatively low temperature, productivity and adhesive strength can be improved.

[0136] One embodiment of the present invention relates to an image display device including the heat sink described above. The image display device may include, but is not limited to, a liquid crystal display (LCD), an organic light emitting diode (OLED), etc., and may include any applicable image display device known in the art. In particular, the image display device may be a flexible display.

[0137] The present invention will be described in more detail below with reference to Examples, Comparative Examples, and Experimental Examples. Note that these Examples, Comparative Examples, and Experimental Examples are provided for the purpose of illustrating the present invention, and it will be apparent to those skilled in the art that the scope of the present invention is not limited to these Examples, Comparative Examples, and Experimental Examples.

[0138] Synthesis Example 1: Synthesis of first alkali-soluble resin A 1 L flask equipped with a reflux condenser, dropping funnel, and stirrer was filled with nitrogen at a rate of 0.02 L / min to create a nitrogen atmosphere, and 250 g of diethylene glycol methyl ethyl ether was added and heated to 70°C with stirring. Next, 132.2 g (0.60 mol) of a mixture of compounds represented by the following chemical formulas a and b (molar ratio 50:50), 42.7 g (0.30 mol) of glycidyl methacrylate, and 8.6 g (0.10 mol) of methacrylic acid dissolved in 100 g of diethylene glycol methyl ethyl ether was added.

[0139] [ka]

[0140] The prepared solution was added dropwise to the flask using a dropping funnel, and then a solution of 27.9 g (0.11 mol) of the polymerization initiator 2,2'-azobis(2,4-dimethylvaleronitrile) dissolved in 200 g of diethylene glycol methyl ethyl ether was added dropwise to the flask using a separate dropping funnel over 4 hours. After the addition of the polymerization initiator solution was completed, the temperature was maintained at 70 °C for 4 hours and then cooled to room temperature to obtain a solution of a first alkali-soluble resin (A-1) containing a repeating unit represented by the following chemical formula 1-1a, with a solids content of 36.7 mass% and an acid value of 59 mg KOH / g (solids equivalent), and the weight average molecular weight (Mw) was 8,400 and the molecular weight distribution was 1.89.

[0141] [ka]

[0142] In the above formula, o represents 60 mol %, p represents 30 mol %, and q represents 10 mol %.

[0143] Synthesis Example 2: Synthesis of second alkali-soluble resin A 1 L flask equipped with a reflux condenser, a dropping funnel, and a stirrer was filled with nitrogen at a rate of 0.02 L / min to create a nitrogen atmosphere, and 200 g of diethylene glycol methyl ethyl ether acetate was added. The temperature was raised to 100°C, and then 10.4 g (0.10 mol) of styrene and tricyclo[5.2.1.0 2,6 ] After adding 55.1 g (0.25 mol) of decanyl methacrylate, 12.9 g (0.15 mol) of methacrylic acid, and 71.1 g (0.50 mol) of glycidyl methacrylate, a solution of 2.0 g of 2,2'-azobis(2,4-dimethylvaleronitrile) dissolved in 100 g of diethylene glycol methyl ethyl ether was added dropwise from the dropping funnel to the flask over 2 hours, and stirring was continued for an additional 5 hours at 100°C. After the reaction was completed, a second alkali-soluble resin (A-2) containing a repeating unit represented by the following chemical formula 2-1a was obtained, with an acid value of 55 mg KOH / g of solids. The weight-average molecular weight (Mw / Mn) measured by GPC in terms of polystyrene was 23,500, and the molecular weight distribution (Mw / Mn) was 2.3.

[0144] [ka]

[0145] In the above formula, o represents 10 mol %, p represents 25 mol %, q represents 15 mol %, and r represents 50 mol %.

[0146] Production Example 1: Production of photosensitive resin composition The composition was a mixture of 9.22% by weight of the first alkali-soluble resin of Synthesis Example 1, 3.95% by weight of the second alkali-soluble resin of Synthesis Example 2, 8.78% by weight of dipentaerythritol hexaacrylate, 0.66% by weight of a multifunctional thiol compound represented by the following chemical formula 3a, 0.77% by weight of 2,2'-bis(o-chlorophenyl)-4,5,4',5'-tetraphenyl-1,2'-biimidazole (B-CIM, Hodogaya Chemical Co., Ltd.) as a photopolymerization initiator, and A photosensitive resin composition was prepared by mixing 0.44 wt% of the oxime compound represented by 4a, 26.60 wt% of diethylene glycol methyl ethyl ether, 30.40 wt% of propylene glycol monomethyl ether acetate, and 19.00 wt% of 3-methoxy-1-butanol as solvents, and 0.18 wt% of 4,4'-butylidenebis[6-tert-butyl-3-methylphenol] (BBM-S, Sumitomo Fine Chemicals) as an antioxidant.

[0147] [ka]

[0148] Example 1: Manufacturing of heat sink The photosensitive resin composition of Production Example 1 was spin-coated onto one side of a copper foil substrate (components: Cu / Ni alloy, Cu 97% by weight, Ni 3% by weight, thickness: 100 μm) as a metal foil, and then pre-baked on a hot plate at 100°C for 5 minutes. After cooling to room temperature, the substrate was exposed to i-rays (wavelength: 365 nm) at 100 mJ / cm with a distance of 180 μm from a quartz glass photomask. 2 After the light irradiation, the coating was developed by immersing it in a 0.045 wt % KOH aqueous solution at room temperature for 60 seconds, washed with water, dried, and then post-baked in a clean oven at 110°C for 20 minutes. After cooling to room temperature, the photosensitive resin composition of Preparation Example 1 was spin-coated on the other side of the copper foil substrate, and the same steps were repeated to produce a heat sink having a corrosion-resistant passivation film formed on both sides of the copper foil substrate.

[0149] Experimental example 1: Evaluation of corrosion resistance The corrosion resistance of the heat sinks of the above examples was evaluated using a WEISS SC450 in accordance with the accelerated saltwater corrosion test for metals as follows: For comparison, the corrosion resistance of a copper foil substrate (composition: Cu / Ni alloy, Cu 97% by weight, Ni 3% by weight, thickness: 100 μm) without a corrosion-resistant passivation film was also evaluated under the same conditions.

[0150] Specifically, the four sides of the manufactured heat sink were fixed with tape to open the test area, and the area was continuously sprayed with 5 wt% salt water (NaCl) and left at 35°C for 72 hours. The surface condition before and after leaving the area was compared to determine the degree of corrosion.

[0151] The corrosion resistance of the heat sinks of the examples was evaluated by leaving them in a salt water spray and then checking the corrosion site on the surface of the copper foil substrate.

[0152] The results are shown in Figures 2 to 4.

[0153] Fig. 2 is a photograph of the surface of the copper foil substrate before exposure to salt water, Fig. 3 is a photograph of the surface of the copper foil substrate without a corrosion-resistant passivation film after exposure to salt water, and Fig. 4 is a photograph of the surface of the copper foil substrate of the heat sink of Example 1 after exposure to salt water.

[0154] 2 to 4, it can be seen that the heat sink of Example 1, which includes a corrosion-resistant passivation film formed from the photosensitive resin composition of the present invention, has excellent corrosion resistance, whereas the copper foil substrate, which does not have a corrosion-resistant passivation film formed thereon, has poor corrosion resistance.

[0155] Experimental Example 2: Transmittance The transmittance was measured using a spectrophotometer (Minolta CM-3600A).

[0156] Before measuring the sample, white calibration was performed in air to check whether 100% transmittance was obtained without a sample. After this, the sample was placed and the transmittance was measured in the wavelength range of 360 to 740 nm. When the transmittance was measured after applying a corrosion-resistant passivation film to the metal foil, it was impossible to confirm the transmittance due to the metal foil, and since the corrosion-resistant passivation film cannot be formed without a substrate, the transmittance was obtained by comparing the transmittance of the optical transparent substrate (23 μm PET) with the transmittance of the corrosion-resistant passivation film applied to the transparent substrate.

[0157] The results are shown in Figure 5.

[0158] From FIG. 5, it can be seen that the corrosion-resistant passivation film exhibits a transmittance of 89% or more in the visible light (360 to 740 nm) wavelength band.

[0159] Experimental example 3: Adhesion The adhesion strength was evaluated in accordance with the standard ASTM D3359. Specifically, the top surface of the corrosion-resistant passivation film was cut with a cutter, with 11 cuts in each direction at 1 mm intervals, to form a grid of 100 squares measuring 1 mm each. Nichiban's CT-24 adhesive tape was then attached to the cut surface, and the condition of the peeled surface was measured when the adhesive tape was peeled off, and evaluated according to the following criteria.

[0160] <Evaluation criteria> 5B: When there is no peeled surface 4B: When the peeled surface is less than 5% of the total area 3B: When the peeled surface is 5% or more but less than 15% of the total area 2B: When the peeled surface is 15% or more but less than 35% of the total area 1B: When the peeled surface is 35% or more but less than 65% of the total area 0B: When the peeled surface is 65% or more of the total area As a result, it was confirmed that the heat sink of Example 1, which includes the corrosion-resistant passivation film formed from the photosensitive resin composition according to the present invention, exhibited adhesion strength of 5B level. [Explanation of symbols]

[0161] 100: Metal foil 201: First corrosion-resistant passivation film 202: Second corrosion-resistant passivation film

Claims

1. Metal foil, and a corrosion-resistant passivation film formed on at least one surface of the metal foil; the corrosion-resistant passivation film is formed from a photosensitive resin composition; The photosensitive resin composition includes an alkali-soluble resin, a photopolymerizable compound, a photopolymerization initiator, and a solvent, and the alkali-soluble resin includes an alkali-soluble resin including a repeating unit having an epoxy group.

2. 2. The heat sink of claim 1, wherein the metal foil comprises a metal or an alloy thereof selected from the group consisting of copper (Cu), aluminum (Al), nickel (Ni), magnesium (Mg), zinc (Zn), tantalum (Ta), titanium (Ti), tungsten (W), molybdenum (Mo), tin (Sn), and indium (In).

3. The heat sink according to claim 1, wherein the metal foil has a thickness of 70 to 150 μm.

4. The heat sink according to claim 1 , wherein the alkali-soluble resin comprises a first alkali-soluble resin containing a repeating unit having an epoxy group-containing crosslinked ring group, and a second alkali-soluble resin containing a repeating unit having an aromatic ring group.

5. The heat sink according to claim 1 , wherein the corrosion-resistant passivation film has a visible light transmittance of 89% or more.

6. 2. The heat sink according to claim 1, wherein the corrosion-resistant passivation film has a thickness of 1 to 5 μm.

7. The heat sink of claim 1 , wherein the corrosion-resistant passivation film is patterned.

8. A step of applying a photosensitive resin composition to at least one surface of a metal foil to obtain a coating film; drying the coating; photocuring the dried coating; and post-baking the photocured coating to form a corrosion-resistant passivation layer; The method for producing a heat sink, wherein the photosensitive resin composition comprises an alkali-soluble resin, a photopolymerizable compound, a photopolymerization initiator, and a solvent, and the alkali-soluble resin comprises an alkali-soluble resin containing a repeating unit having an epoxy group.

9. The method for manufacturing a heat sink according to claim 8 , further comprising the steps of: performing light irradiation using a mask in the photo-curing step; and developing the photo-cured coating film after the photo-curing step.

10. 9. The method for manufacturing a heat sink according to claim 8, wherein the alkali-soluble resin comprises a first alkali-soluble resin containing a repeating unit having an epoxy group-containing crosslinked ring group, and a second alkali-soluble resin containing a repeating unit having an aromatic ring group.

11. The method for manufacturing a heat sink according to claim 8, wherein the post-baking is performed at 90 to 150°C.

12. An image display device comprising the heat sink according to any one of claims 1 to 7.

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