Gas barrier film and wavelength conversion sheet

Abstract

The gas barrier film according to one aspect of the present disclosure is formed by layering, in order, a base material, a first AlOx vapor deposition layer, a gas barrier intermediate layer, a second AlOx vapor deposition layer, and a gas barrier coating layer. The first AlOx vapor deposition layer and the second AlOx vapor deposition layer are each no more than 15 nm thick, the gas barrier intermediate layer and the gas barrier coating layer are each 200–400 nm thick, and the composite modulus of elasticity of the gas barrier coating layer as measured by nanoindentation is 7–11 GPa at a measurement temperature of 25°C and 5–8 GPa at a measurement temperature of 60°C.

Description

Technical Field

[0001] The present disclosure relates to a gas barrier film and a wavelength conversion sheet.

Background Art

[0002] In display devices such as organic EL displays and QD liquid crystal displays using quantum dots, and solar cells, etc., a gas barrier film is used to prevent quality deterioration due to water vapor, oxygen, etc. (see Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] The gas barrier film used for the above-mentioned applications is required not only to have gas barrier properties but also transparency. For example, in a QD liquid crystal display, quantum dots (QDs) are used in a wavelength conversion layer for converting blue LEDs to white. However, since quantum dots are easily deteriorated, a gas barrier film is laminated so as to cover both sides of the wavelength conversion layer. In this case, since the light emission color converted depends on the transparency of the gas barrier film, particularly the intensity of yellowness, it is required that the yellowness of the gas barrier film be reduced. Furthermore, the gas barrier film used for the above-mentioned applications is required to have suppressed wrinkles and good appearance from the viewpoints of improving transparency and suppressing color unevenness, etc.

[0005] This disclosure is made in view of the above circumstances and aims to provide a gas barrier film that has excellent water vapor barrier properties, can reduce yellowing, and can suppress the occurrence of wrinkles, and a wavelength conversion sheet using the same. [Means for solving the problem]

[0006] To achieve the above objective, this disclosure provides a substrate and a first AlO x A vapor-deposited layer, a gas barrier intermediate layer, and a second AlO x The structure has a vapor-deposited layer and a gas barrier coating layer stacked in this order, and the first AlO x The vapor-deposited layer and the second AlO x The present invention provides a gas barrier film in which the thickness of each vapor-deposited layer is 15 nm or less, the thickness of both the gas barrier intermediate layer and the gas barrier coating layer is 200 to 400 nm, and the composite elastic modulus of the gas barrier coating layer, as measured by nanoindentation, is 7 to 11 GPa at a measurement temperature of 25°C and 5 to 8 GPa at a measurement temperature of 60°C.

[0007] According to the above gas barrier film, having the above laminated structure, with the thickness of each layer within the above range, and the gas barrier coating layer satisfying the above composite elastic modulus conditions, excellent oxygen and water vapor barrier properties can be obtained, yellowing can be reduced, and wrinkle formation can be suppressed. In addition, the first and second AlO x By setting the thickness of the vapor-deposited layer to 15 nm or less, and the thickness of the gas barrier intermediate layer and gas barrier coating layer to 200-400 nm, the gas barrier intermediate layer and gas barrier coating layer, and the first and second AlO are used, particularly in the wavelength range of blue LEDs (300-400 nm), where the effect on the conversion efficiency of the wavelength conversion sheet is significant. x Reflection and interference at the interface with the deposited layer can be reduced. Furthermore, the first AlO x Vapor deposition layer and second AlO xBy providing the vapor deposition layer, the gas barrier intermediate layer, and the gas barrier coating layer separately, the thickness of each layer can be reduced, the occurrence of wrinkles and cracks can be suppressed, and the total thickness of the layer imparting gas barrier properties can be ensured, so that good gas barrier properties can be obtained. Further, by setting the complex elastic modulus of the gas barrier coating layer within the above range, it is possible to achieve both barrier properties against oxygen and water vapor and deformation resistance when the substrate is deformed by heat treatment or the like.

[0008] In the above gas barrier film, the hardness of the gas barrier coating layer measured by nanoindentation method is preferably 1.15 to 1.70 GPa at a measurement temperature of 25°C and 0.85 to 1.30 GPa at a measurement temperature of 60°C. When the gas barrier coating layer satisfies the above hardness conditions, more excellent oxygen and water vapor barrier properties can be obtained, the yellowness can be further reduced, and the occurrence of wrinkles can be further suppressed.

[0009] In the above gas barrier film, the substrate preferably has its surface on the vapor deposition layer side plasma-treated. x By using a substrate whose surface on the vapor deposition layer side is plasma-treated, the adhesion between the substrate and the first AlO x vapor deposition layer can be improved, and delamination between these layers can be suppressed. Further, by using a substrate whose surface on the vapor deposition layer side is plasma-treated, the adhesion between the layers can be improved by plasma treatment without forming a layer for improving adhesion such as an anchor coat layer, etc., so that the light transmittance can be improved as compared with the case of providing an anchor coat layer or the like. x vapor deposition layer can be improved, and delamination between these layers can be suppressed. x vapor deposition layer can be improved, and delamination between these layers can be suppressed. Further, by using a substrate whose surface on the vapor deposition layer side is plasma-treated, the adhesion between the layers can be improved by plasma treatment without forming a layer for improving adhesion such as an anchor coat layer, etc., so that the light transmittance can be improved as compared with the case of providing an anchor coat layer or the like.

[0010] In the above-described gas barrier film, it is preferable that the gas barrier coating layer is formed using a gas barrier coating layer forming composition containing at least one selected from the group consisting of a hydroxyl group-containing polymer compound, a metal alkoxide, a silane coupling agent, and their hydrolysates. By including the above components in the gas barrier coating layer forming composition, the composite elastic modulus and hardness of the gas barrier coating layer can be easily controlled within the above-described range, and superior oxygen and water vapor barrier properties can be obtained. Furthermore, when a hydroxyl group-containing polymer compound and a hydrolysate of a metal alkoxide are used in combination, strong hydrogen bonds are formed between the hydroxyl groups of the hydroxyl group-containing polymer compound and the hydroxyl groups of the hydrolysate of the metal alkoxide, resulting in higher gas barrier properties.

[0011] The disclosure also provides a wavelength conversion sheet comprising a phosphor layer and a gas barrier film of the disclosure disposed on at least one surface of the phosphor layer. [Effects of the Invention]

[0012] According to this disclosure, it is possible to provide a gas barrier film that has excellent water vapor barrier properties, can reduce yellowing, and can suppress the occurrence of wrinkles, as well as a wavelength conversion sheet using the same. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic cross-sectional view showing one embodiment of a gas barrier film. [Figure 2] This is a schematic cross-sectional view showing one embodiment of a wavelength conversion sheet. [Modes for carrying out the invention]

[0014] Embodiments of this disclosure will be described in detail below with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0015] [Gas barrier film] Figure 1 is a schematic cross-sectional view showing one embodiment of the gas barrier film of the present disclosure. The gas barrier film 100 according to this embodiment comprises a substrate 11 and a first AlO provided on the substrate 11. x The vapor-deposited layer 13 and the first AlO x A gas barrier intermediate layer 14 is provided on the vapor-deposited layer 13, and a second AlO is provided on the gas barrier intermediate layer 14. x The vapor-deposited layer 23 and the second AlO x The gas barrier film 100 comprises a gas barrier coating layer 24 provided on a vapor deposition layer 23. x A first barrier layer 15 consisting of a vapor-deposited layer 13 and a gas barrier intermediate layer 14, and a second AlO x It comprises a second barrier layer 25 consisting of a vapor-deposited layer 23 and a gas barrier coating layer 24.

[0016] (Base material 11) The base material 11 is preferably a polymer film. Examples of polymer film materials include, but are not limited to, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamides such as nylon; polyolefins such as polypropylene and cycloolefin; polycarbonate; and triacetylcellulose. The polymer film is preferably a polyester film, polyamide film, or polyolefin film, more preferably a polyester film or polyamide film, and even more preferably a polyethylene terephthalate film. A polyethylene terephthalate film is desirable from the viewpoint of transparency, processability, and adhesion. Furthermore, from the viewpoint of transparency and gas barrier properties, a biaxially oriented polyethylene terephthalate film is preferred.

[0017] The base material 11 may optionally contain additives such as antistatic agents, ultraviolet absorbers, plasticizers, and lubricants. xAn anchor coat layer may be provided on the surface 11a on the vapor-deposited layer 13 side. The anchor coat layer can be formed using a resin selected from, for example, polyester resin, isocyanate resin, urethane resin, acrylic resin, polyvinyl alcohol resin, ethylene vinyl alcohol resin, vinyl-modified resin, epoxy resin, oxazoline group-containing resin, modified styrene resin, modified silicone resin, or alkyl titanate. The anchor coat layer can be formed using one of the above-mentioned resins alone, or using a composite resin that combines two or more of the above-mentioned resins. The thickness of the anchor coat layer is, for example, 0.001 μm to 2 μm. In particular, by forming the anchor coat layer in-line during film deposition of the substrate 11 and stretching it to create a substrate film with an anchor coat layer (easy-adhesion layer), the thickness of the anchor coat layer can be made very thin (for example, 0.02 μm or less), thereby reducing energy loss in the anchor coat layer.

[0018] Also, the first AlO of the substrate 11 x The surface 11a on the vapor-deposited layer 13 side may be subjected to surface treatments such as corona treatment, flame treatment, and plasma treatment. In particular, AlO x By providing the vapor-deposited layer 13, energy loss in the anchor coat layer, etc., is eliminated compared to the case where an anchor coat layer, etc., is provided, thereby improving light transmittance. As for the plasma treatment, the following reactive ion etching treatment is preferred.

[0019] The substrate 11 may have a modified layer formed by reactive ion etching (hereinafter also referred to as "RIE") on its surface 11a. The modified layer refers to a portion of the substrate 11 near its surface that has been modified in a layered manner by the RIE treatment.

[0020] Plasma is used in the RIE treatment. Radicals and ions generated in the plasma provide a chemical effect that imparts functional groups to the surface of the substrate 11. In addition, surface impurities are removed by ion etching, and a physical effect that increases the surface roughness is also obtained. Therefore, the modified treatment layer exhibiting the above chemical and physical effects through the RIE treatment allows the substrate 11 and the first AlO to bond. x The adhesion between the vapor-deposited layer 13 is improved, and the substrate 11 and the first AlO remain stable even in high temperature and high humidity environments. x This reduces the likelihood of delamination between the vapor-deposited layer 13 and the surrounding material.

[0021] The RIE treatment of the substrate 11 can be carried out using a known RIE-type plasma processing apparatus. A winding-type inline plasma processing apparatus is preferred as the plasma processing apparatus. As a winding-type inline plasma processing apparatus, a planar-type plasma processing apparatus, a hollow-anode-type plasma processing apparatus, etc., can be used.

[0022] The thickness of the substrate 11 is not particularly limited, but is preferably 3 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less. If the thickness is 3 μm or more, it is easy to process, and if it is 100 μm or less, the total thickness of the gas barrier film can be reduced.

[0023] (First AlO x Deposition layer 13 and second AlO x Vapor deposited layer 23) In this embodiment, the first AlO x The vapor-deposited layer 13 is formed on the substrate 11 by vapor deposition. Also, the second AlO x The vapor-deposited layer 23 is formed by vapor deposition on the gas barrier intermediate layer 14. x Deposition layer 13 and second AlO x The vapor-deposited layer 23 is AlO x This is a layer containing aluminum oxide. xThis is preferred because it has high transparency and is easy to reduce yellowness. Here, the value of x is preferably 0.01 to 2.00, and more preferably 1.00 to 1.90, because it is easy to obtain good gas barrier properties and easy to reduce yellowness. First AlO x Deposition layer 13 and second AlO x The vapor-deposited layer 23 may have the same configuration or a different configuration.

[0024] First AlO x Deposition layer 13 and second AlO x For example, when forming the vapor deposition layer 23, the following methods can be used for vapor deposition: resistance heating vacuum deposition, EB (Electron Beam) heating vacuum deposition, induction heating vacuum deposition, etc.

[0025] First AlO x Deposition layer 13 and second AlO x The film thickness of the vapor-deposited layer 23 is 15 nm or less, and preferably 13 nm or less. By keeping this film thickness below the above upper limit, the transparency of the gas barrier film can be improved and the yellowing can be reduced. On the other hand, the first AlO x Deposition layer 13 and second AlO x The film thickness of the vapor-deposited layer 23 is preferably 5 nm or more, and more preferably 8 nm or more. By setting this film thickness to above the lower limit mentioned above, better gas barrier properties can be obtained.

[0026] (Gas barrier intermediate layer 14 and gas barrier coating layer 24) In this embodiment, the gas barrier intermediate layer 14 and the gas barrier coating layer 24 are provided to prevent various secondary damages in subsequent processes and to provide high gas barrier properties. The gas barrier intermediate layer 14 and the gas barrier coating layer 24 may have the same configuration or different configurations.

[0027] The gas barrier intermediate layer 14 and the gas barrier coating layer 24 are preferably layers formed using a composition containing at least one selected from the group consisting of hydroxyl group-containing polymer compounds, metal alkoxides, silane coupling agents, and their hydrolysates. The gas barrier intermediate layer 14 and the gas barrier coating layer 24 having such a configuration can be formed using a composition (hereinafter also referred to as a coating agent) mainly composed of an aqueous solution or a water / alcohol mixed solution containing at least one selected from the group consisting of hydroxyl group-containing polymer compounds, metal alkoxides, silane coupling agents, and their hydrolysates. From the viewpoint of further improving gas barrier properties, the coating agent preferably contains at least a silane coupling agent or its hydrolysate, more preferably at least one selected from the group consisting of hydroxyl group-containing polymer compounds, metal alkoxides, and their hydrolysates, and a silane coupling agent or its hydrolysate, and even more preferably a hydroxyl group-containing polymer compound or its hydrolysate, a metal alkoxide or its hydrolysate, and a silane coupling agent or its hydrolysate. For example, a coating agent can be prepared by mixing a solution of a hydroxyl group-containing polymer compound, which is a water-soluble polymer, in an aqueous solvent (water or a water / alcohol mixture), with a metal alkoxide and a silane coupling agent, either directly or after being subjected to a prior hydrolysis treatment.

[0028] The components of the coating agent for forming the gas barrier intermediate layer 14 and the gas barrier coating layer 24 will be described in detail. Examples of hydroxyl group-containing polymer compounds used in the coating agent include polyvinyl alcohol, polyvinylpyrrolidone, starch, methylcellulose, carboxymethylcellulose, and sodium alginate. Among these, polyvinyl alcohol (hereinafter abbreviated as PVA) is preferred when used as the coating agent for the gas barrier intermediate layer 14 and the gas barrier coating layer 24 because it exhibits particularly excellent gas barrier properties.

[0029] From the viewpoint of obtaining excellent gas barrier properties, the gas barrier intermediate layer 14 and the gas barrier coating layer 24 are preferably formed from a composition containing at least one selected from the group consisting of metal alkoxides represented by the following general formula (1) and their hydrolysates. M(OR 1 ) m (R 2 ) n-m …(1) In the above general formula (1), R 1 and R 2 Each of these is independently a monovalent organic group having 1 to 8 carbon atoms, preferably an alkyl group such as a methyl group or an ethyl group. M represents an n-valent metal atom such as Si, Ti, Al, or Zr. m is an integer from 1 to n. Note that R 1 or R 2 If there are multiple instances, R 1 Mutual or R 2 They may be the same or different.

[0030] Examples of metal alkoxides include tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum [Al(O-2'-C3H7)3]. Tetraethoxysilane and triisopropoxyaluminum are preferred because they are relatively stable in aqueous solvents after hydrolysis.

[0031] Examples of silane coupling agents include compounds represented by the following general formula (2). By using a silane coupling agent represented by the following general formula (2), the water resistance and heat resistance of the gas barrier film can be further improved. Si(OR 11 ) p (R 12 ) 3-p R 13 …(2) In the above general formula (2), R 11 R represents an alkyl group such as a methyl group or an ethyl group. 12 R represents a monovalent organic group such as an alkyl group, aralkyl group, aryl group, alkenyl group, alkyl group substituted with an acryloxy group, or alkyl group substituted with a methacryloxy group. 13indicates a monovalent organic functional group, and p is an integer from 1 to 3. Note that R 11 or R 12 If there are multiple instances, R 11 Mutual or R 12 They may be the same or different. 13 Examples of monovalent organic functional groups represented by include monovalent organic functional groups containing a glycidyloxy group, epoxy group, mercapto group, hydroxyl group, amino group, alkyl group substituted with a halogen atom, or isocyanate group.

[0032] Specific examples of silane coupling agents include vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, and γ-methacryloxypropylmethyldimethoxysilane.

[0033] Furthermore, the silane coupling agent may be a polymer of the compound represented by the general formula (2) described above. A trimer is preferred as the polymer, and more preferably 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate. This is a condensed polymer of 3-isocyanate alkylalkoxysilane. It is known that in 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate, the isocyanate portion loses its chemical reactivity, but the reactivity is maintained by the polarity of the nulate portion. Generally, it is added to adhesives and the like, similar to 3-isocyanate alkylalkoxylane, and is known as an adhesion improver. Therefore, by adding 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate to a hydroxyl group-containing polymer compound, the water resistance of the gas barrier intermediate layer 14 and the gas barrier coating layer 24 can be improved by hydrogen bonding. While 3-isocyanate alkylalkoxylanes are highly reactive and have low liquid stability, 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate, although its nurate portion is not water-soluble due to its polarity, disperses easily in aqueous solutions and can maintain stable liquid viscosity. Furthermore, the water resistance performance of 3-isocyanate alkylalkoxylanes and 1,3,5-tris(3-trialkoxysilylalkyl)isocyanurate is equivalent.

[0034] 1,3,5-Tris(3-trialkoxysilylalkyl)isocyanurate can also be produced by thermal condensation of 3-isocyanatetopropylalkoxysilane, and may contain the raw material 3-isocyanatetopropylalkoxysilane, but this does not pose a particular problem. More preferably, it is 1,3,5-tris(3-trialkoxysilylpropyl)isocyanurate, and more preferably, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate. Since the methoxy group hydrolyzes quickly and those containing the propyl group are relatively inexpensive to obtain, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate is practically advantageous.

[0035] Furthermore, known additives such as isocyanate compounds, dispersants, stabilizers, and viscosity modifiers may be added to the coating agent as needed, provided that they do not impair the gas barrier properties.

[0036] The coating agent for forming the gas barrier intermediate layer 14 and the gas barrier coating layer 24 can be applied by methods such as dipping, roll coating, gravure coating, reverse gravure coating, air knife coating, comma coating, die coating, screen printing, spray coating, and gravure offset. The coating film formed by applying this coating agent can be dried by methods such as hot air drying, hot roll drying, high-frequency irradiation, infrared irradiation, UV irradiation, or a combination thereof.

[0037] The temperature at which the above coating film is dried can be, for example, 50 to 150°C, and preferably 70 to 100°C. By keeping the drying temperature within the above range, the first AlO x Deposition layer 13 and second AlO x This further suppresses the occurrence of cracks in the vapor-deposited layer 23, the gas barrier intermediate layer 14, and the gas barrier coating layer 24, enabling the development of excellent gas barrier properties.

[0038] The thickness of both the gas barrier intermediate layer 14 and the gas barrier coating layer 24 is 200 to 400 nm after curing, preferably 230 to 380 nm, and more preferably 250 to 350 nm. By keeping this film thickness below the upper limit, the transparency of the gas barrier film can be improved, the yellowing can be reduced, and the occurrence of wrinkles in the gas barrier intermediate layer 14 and the gas barrier coating layer 24 can be suppressed. On the other hand, by keeping this film thickness above the lower limit, good gas barrier properties can be obtained.

[0039] The combined thickness of the gas barrier intermediate layer 14 and the gas barrier coating layer 24 is preferably 400 to 800 nm, and more preferably 450 to 600 nm. The thickness of the gas barrier intermediate layer 14 and the thickness of the gas barrier coating layer 24 may be different. The ratio of the thickness of the gas barrier intermediate layer 14 to the thickness of the gas barrier coating layer 24 (thickness of gas barrier intermediate layer 14 / thickness of gas barrier coating layer 24) may be 1.0 to 2.0, greater than 1.0 and 2.0 or less, or 1.1 to 1.5. By making the thickness of the gas barrier coating layer 24 the same as or thinner than the thickness of the gas barrier intermediate layer 14, it is easier to suppress the occurrence of wrinkles and to make the gas barrier coating layer 24 harder.

[0040] In this embodiment, the gas barrier coating layer 24 has a composite modulus of elasticity measured by nanoindentation of 7 to 11 GPa at a measurement temperature of 25°C and 5 to 8 GPa at a measurement temperature of 60°C. Furthermore, it is preferable that the hardness of the gas barrier coating layer 24, as measured by nanoindentation, is 1.15 to 1.70 GPa at a measurement temperature of 25°C and 0.85 to 1.30 GPa at a measurement temperature of 60°C. The composite modulus of elasticity and hardness of the gas barrier coating layer 24 can be adjusted by controlling the crosslinking density by the composition of the coating agent (especially the amount of silane coupling agent) and the heating temperature during layer formation.

[0041] In this specification, the composite modulus and hardness of the gas barrier coating layer 24 refer to the composite modulus and hardness calculated by the nanoindentation method. The nanoindentation method is a measurement method that obtains the mechanical properties of a sample by performing a quasi-static indentation test on the target object to be measured. The composite modulus and hardness can be measured, for example, with the following apparatus.

[0042] The measurement device used was a Hysitron TI-Premier (product name) manufactured by Bruker Japan Co., Ltd., equipped with a nanoDMA III transducer (product name). The indenter used was a Berkovich-type diamond heating indenter TI-0283 (product name) with a tip opening angle of 142.3°. The measurement temperature was controlled using a heating stage xSol400 (product name) manufactured by Bruker Japan Co., Ltd. The heating rate during temperature control was set to 20°C / min, and after the heating stage reached the desired temperature, it was held for 10 minutes before measurement. In addition, fused silica, which would serve as the standard sample, was tested in advance to calibrate the relationship between contact depth and contact projected area. For the nanoindentation method, the measurement conditions were as follows: in a quasi-static test, the sample was indented to a depth of 30 nm at an indentation speed of 30 nm / second, held at the maximum depth for 1 second, and then unloaded at a speed of 30 nm / second. By analyzing the unloading curve results in the 60-95% range relative to the maximum load during unloading, the composite modulus and stiffness were calculated using the Oliver-Pharr method.

[0043] The composite modulus of the gas barrier coating layer 24, as measured by nanoindentation, is 7 to 11 GPa at a measurement temperature of 25°C, but preferably 7.5 to 10.5 GPa. Furthermore, the composite modulus of the gas barrier coating layer 24, as measured by nanoindentation, is 5 to 8 GPa at a measurement temperature of 60°C, but preferably 5.5 to 7.5 GPa. By keeping this composite modulus below the upper limit, the occurrence of wrinkles in the gas barrier coating layer 24 can be suppressed, and by keeping it above the lower limit, good gas barrier properties can be obtained.

[0044] The hardness of the gas barrier coating layer 24, as measured by nanoindentation, is preferably 1.15 to 1.70 GPa, and more preferably 1.20 to 1.65 GPa, at a measurement temperature of 25°C. Furthermore, the hardness of the gas barrier coating layer 24, as measured by nanoindentation, is preferably 0.85 to 1.30 GPa, and more preferably 0.90 to 1.30 GPa, at a measurement temperature of 60°C. If this hardness is below the upper limit, the occurrence of wrinkles in the gas barrier coating layer 24 can be further suppressed, and if it is above the lower limit, even better gas barrier properties can be obtained.

[0045] Although a preferred embodiment of the gas barrier film of the present disclosure has been described above, the gas barrier film of the present disclosure is not limited to the above embodiment. The gas barrier film comprises a substrate 11 and a first AlO x Between the vapor-deposited layer 13, the first AlO x Between the vapor-deposited layer 13 and the gas barrier intermediate layer 14, the gas barrier intermediate layer 14 and the second AlO x Between the vapor-deposited layer 23 and the second AlO x A separate layer may or may not be provided between the vapor-deposited layer 23 and the gas barrier coating layer 24. If no separate layer is provided, the above layers are in contact with each other. In addition, the gas barrier film may have further barrier layers in addition to the first barrier layer 15 and the second barrier layer 25. However, as the number of barrier layers increases, transparency tends to decrease, and wrinkles and curls tend to occur in the gas barrier film as the number of heating cycles during layer formation increases. For this reason, it is preferable that the gas barrier film has only the first barrier layer 15 and the second barrier layer 25 as barrier layers. In addition, the gas barrier film may further have the following mat layers.

[0046] (Matte layer) A matte layer is provided on the outermost surface of a gas barrier film to exhibit one or more optical functions or antistatic functions. For example, when a gas barrier film is used to protect a phosphor layer in a wavelength conversion sheet, the matte layer is provided on the surface of the gas barrier film opposite to the phosphor layer. Here, the optical functions are not particularly limited, but include interference fringe (moire) prevention, anti-reflection, and diffusion functions. Among these, it is preferable that the matte layer has at least an interference fringe prevention function as an optical function. In this embodiment, the case in which the matte layer has at least an interference fringe prevention function will be described.

[0047] The mat layer may consist of a binder resin and fine particles. The fine particles may be embedded in the binder resin such that some of them are exposed from the surface of the mat layer, resulting in fine irregularities on the surface of the mat layer. By providing such a mat layer on the surface of the gas barrier film, the generation of interference fringes such as Newton's rings can be more effectively prevented, and as a result, a highly efficient, high-resolution, and long-life wavelength conversion sheet can be obtained.

[0048] While there are no particular limitations on the binder resin, any resin with excellent optical transparency can be used. More specifically, thermoplastic resins, thermosetting resins, and ionizing radiation-curable resins such as polyester resins, acrylic resins, acrylic urethane resins, polyester acrylate resins, polyurethane acrylate resins, urethane resins, epoxy resins, polycarbonate resins, polyamide resins, polyimide resins, melamine resins, and phenolic resins can be used. In addition to organic resins, silica binders can also be used. Among these, acrylic resins and urethane resins are preferable due to their wide range of materials, and acrylic resins are even more preferable due to their excellent light resistance and optical properties. These can be used in combination, not just individually.

[0049] While there are no particular limitations on the types of microparticles used, examples include inorganic microparticles such as silica, clay, talc, calcium carbonate, calcium sulfate, barium sulfate, titanium dioxide, and alumina, as well as organic microparticles such as styrene resin, urethane resin, silicone resin, acrylic resin, and polyamide resin. Among these, microparticles made of silica, acrylic resin, urethane resin, polyamide resin, etc., with a refractive index of 1.40 to 1.55 are preferable in terms of transmittance. Microparticles with a low refractive index are expensive, while microparticles with a refractive index that is too high tend to impair transmittance. These can be used not only individually, but also in combination of multiple types.

[0050] The average particle size of the fine particles is preferably 0.1 to 30 μm, and more preferably 0.5 to 10 μm. When the average particle size of the fine particles is 0.1 μm or larger, excellent interference fringe suppression function tends to be obtained, and when it is 30 μm or smaller, transparency tends to be further improved.

[0051] The content of fine particles in the matte layer is preferably 0.5 to 30% by mass, and more preferably 3 to 10% by mass, based on the total amount of the matte layer. When the content of fine particles is 0.5% by mass or more, the effect of light diffusion function and prevention of interference fringe generation tends to be further improved, and when it is 30% by mass or less, there is no reduction in brightness.

[0052] The matte layer can be formed by applying and drying a coating solution containing the aforementioned binder resin and fine particles. Coating methods include gravure coaters, dip coaters, reverse coaters, wire bar coaters, and die coaters.

[0053] The thickness of the matte layer is preferably 0.1 to 20 μm, and more preferably 0.3 to 10 μm. A matte layer thickness of 0.1 μm or more tends to result in a more uniform film and easier acquisition of sufficient optical functionality. On the other hand, a matte layer thickness of 20 μm or less tends to result in the fine particles being exposed on the surface of the matte layer when fine particles are used in the matte layer, making it easier to obtain a textured surface effect.

[0054] The gas barrier film of this embodiment, having the configuration described above, can be used in applications where barrier properties against the permeability of oxygen and water vapor are required. The gas barrier film of this embodiment is useful, for example, as packaging material for food and pharmaceuticals, as a wavelength conversion sheet for backlights of liquid crystal displays such as QD liquid crystal displays using quantum dots, as a sealing member for organic electroluminescence (organic EL) displays, as a wavelength conversion sheet for organic EL lighting, and as a protective sheet for solar cells. In particular, it is preferably used as a wavelength conversion sheet for backlights of liquid crystal displays.

[0055] [Wavelength Conversion Sheet] Figure 2 is a schematic cross-sectional view showing one embodiment of the wavelength conversion sheet of this disclosure. The wavelength conversion sheet shown in Figure 2 contains phosphors such as quantum dots and can be used, for example, in a backlight unit for LED wavelength conversion.

[0056] The wavelength conversion sheet 200 shown in Figure 2 is generally composed of a phosphor layer (wavelength conversion layer) 7 containing a phosphor, and gas barrier films 100, 100 provided on one side 7a and the other side 7b of the phosphor layer 7, respectively. This creates a structure in which the phosphor layer 7 is enclosed (i.e., sealed) between the gas barrier films 100, 100. Here, since it is necessary to impart gas barrier properties to the phosphor layer 7, it is desirable to have a configuration in which the phosphor layer 7 is sandwiched between a pair of gas barrier films 100, 100. The individual layers constituting the wavelength conversion sheet 200 will be described in detail below.

[0057] (Gas barrier film) As the gas barrier films 100, 100, the gas barrier film 100 shown in Figure 1 can be used. In the wavelength conversion sheet 200, the gas barrier film 100 arranged on one side 7a of the phosphor layer 7 and the gas barrier film 100 arranged on the other side 7b may be the same or different.

[0058] As shown in Figure 2, the gas barrier films 100, 100 may be arranged such that the gas barrier coating layer 24 faces the phosphor layer 7, or the substrate 11 faces the phosphor layer 7. From the viewpoint of further suppressing the deterioration of the phosphor layer 7 due to oxygen and water vapor, it is preferable that the gas barrier films 100, 100 are arranged such that the gas barrier coating layer 24 faces the phosphor layer 7. The gas barrier coating layer 24 and the phosphor layer 7 may be in direct contact. In addition, a primer layer may be provided on the gas barrier coating layer 24 to improve the adhesion between the gas barrier coating layer 24 and the phosphor layer 7. The gas barrier film 100 may also be used as a laminate film by bonding it with another film (for example, polyethylene terephthalate film) with an adhesive. The gas barrier film 100 may also be used by laminating two or more layers.

[0059] (Phosphor layer) The phosphor layer 7 is a thin film with a thickness of several tens to several hundred micrometers, containing a sealing resin 9 and phosphors 8. For example, a photosensitive resin or a thermosetting resin can be used as the sealing resin 9. One or more types of phosphors 8 are sealed inside the sealing resin 9 in a mixed state. The sealing resin 9 plays a role in bonding the phosphor layer 7 and a pair of gas barrier films 100, 100 when they are laminated together, and also in filling the gaps between them. Alternatively, the phosphor layer 7 may be a laminate of two or more phosphor layers, each containing only one type of phosphor 8. Two or more types of phosphors 8 used in these one or more phosphor layers are selected to have the same excitation wavelength. This excitation wavelength is selected based on the wavelength of light emitted by the LED light source. The fluorescence colors of the two or more types of phosphors 8 are different from each other. When using two types of phosphors 8 with a blue LED (peak wavelength 450 nm) as the LED light source, the fluorescence colors are preferably red and green. The wavelengths of each fluorescence and the wavelength of light emitted by the LED light source are selected based on the spectral characteristics of the color filter. For example, the peak wavelengths of the fluorescence are 650 nm for red and 550 nm for green.

[0060] Next, the particle structure of the phosphor 8 will be described. Quantum dots are preferably used as the phosphor 8 because they offer high color purity and improved brightness. Examples of quantum dots include those in which a core, acting as a light-emitting part, is coated with a shell, which acts as a protective film. Examples of the core include cadmium selenide (CdSe), and examples of the shell include zinc sulfide (ZnS). The quantum efficiency is improved by covering the surface defects of the CdSe particles with ZnS, which has a large band gap. Alternatively, the phosphor 8 may have a core double-coated with a first shell and a second shell. In this case, CdSe can be used for the core, zinc selenide (ZnSe) for the first shell, and ZnS for the second shell. Furthermore, other phosphors besides quantum dots, such as YAG:Ce, can also be used for the phosphor 8.

[0061] The average particle size of the phosphor 8 is preferably 1 to 20 nm. The thickness of the phosphor layer 7 is preferably 1 to 500 μm.

[0062] The content of the phosphor 8 in the phosphor layer 7 is preferably 1 to 20% by mass, and more preferably 3 to 10% by mass, based on the total amount of the phosphor layer 7.

[0063] As the sealing resin 9, for example, thermoplastic resins, thermosetting resins, and ultraviolet-curing resins can be used. These resins can be used individually or in combination of two or more types.

[0064] Examples of thermoplastic resins that can be used include cellulose derivatives such as acetylcellulose, nitrocellulose, acetylbutylcellulose, ethylcellulose, and methylcellulose; vinyl resins such as vinyl acetate and its copolymers, vinyl chloride and its copolymers, and vinylidene chloride and its copolymers; acetal resins such as polyvinyl formal and polyvinyl butyral; acrylic resins such as acrylic resins and their copolymers, methacrylic resins and their copolymers; polystyrene resins; polyamide resins; linear polyester resins; fluororesins; and polycarbonate resins.

[0065] Examples of thermosetting resins include phenolic resins, urea-melamine resins, polyester resins, and silicone resins.

[0066] Examples of UV-curable resins include photopolymerizable prepolymers such as epoxy acrylate, urethane acrylate, and polyester acrylate. Furthermore, these photopolymerizable prepolymers can be used as the main component, with monofunctional or polyfunctional monomers used as diluents. [Examples]

[0067] The present disclosure will be described in detail below with reference to examples, but the present disclosure is not limited to these examples.

[0068] [Examples 1-6 and Comparative Examples 1-6] <Fabrication of gas barrier film> First, a 12 μm thick biaxially oriented polyethylene terephthalate film was prepared as the substrate. A modified layer was formed on one side of the substrate by RIE treatment using a planar plasma processing apparatus. Next, the first AlO was added to the modified layer. x A vapor-deposited layer was formed. The first AlO x The vapor-deposited layer was formed by vacuum deposition of aluminum oxide onto a modified layer. Specifically, an electron beam heating type vacuum deposition apparatus was used, and metallic aluminum was evaporated while introducing oxygen gas into the apparatus. This resulted in a first AlO layer of a predetermined thickness. x A vapor-deposited layer was formed. Next, a gas barrier intermediate layer and a second AlO layer were added. x The vapor-deposited layer and the gas barrier coating layer were formed in this order. x The vapor-deposited layer is the first AlO x The vapor-deposited layer was formed in the same manner as the vapor-deposited layer. As the gas barrier intermediate layer and gas barrier coating layer, the following coatings A and B were used according to each example and comparative example. By the above method, the substrate / first AlO x Deposition layer / Gas barrier intermediate layer / Second AlO x A gas barrier film was obtained having a structure in which a vapor-deposited layer and a gas barrier coating layer are sequentially laminated.

[0069] (Court A) A solution was prepared by mixing liquids A, B, and C shown below in a ratio of A / B / C = 70 / 20 / 10 (solid content by mass ratio). This solution was then applied by gravure coating and dried to form a gas barrier intermediate layer or gas barrier coating layer of a predetermined thickness.

[0070] (Court B) A solution was prepared by mixing liquids A and B shown below in a ratio of 70 / 30 (solid content by mass). This solution was then applied by gravure coating and dried to form a gas barrier intermediate layer or gas barrier coating layer of a predetermined thickness.

[0071] Solution A: A hydrolysis solution with a solid content of 5% by mass (SiO2 equivalent) obtained by adding 72.1g of 0.1N hydrochloric acid to 17.9g of tetraethoxysilane and 10g of methanol and stirring for 30 minutes. Solution B: A water / methanol aqueous solution containing 5% by mass of polyvinyl alcohol in a mass ratio of 95 / 5. Solution C: A hydrolysis solution of 1,3,5-tris(3-trialkoxysilylpropyl) isocyanurate diluted to a solid content of 5% by mass with a mixture of water and isopropyl alcohol (water:isopropyl alcohol mass ratio is 1:1).

[0072] [Example 7] A gas barrier film was obtained in the same manner as in Example 1, except that a substrate consisting of a 12 μm thick biaxially oriented polyethylene terephthalate film with a barrier layer laminated on the surface on which the barrier layer was laminated, and a 0.005 μm thick anchor coat layer made of aliphatic polyurethane resin was laminated on the surface on which the barrier layer was laminated, and RIE treatment was not performed.

[0073] The type of coating used in each example and comparative example, the drying temperature and time during the formation of the gas barrier intermediate layer and gas barrier coating layer, and the first and second AlO x Table 1 shows the thickness of the vapor-deposited layer (collectively referred to as "vapor-deposited layer" in the table), as well as the thickness of the gas barrier intermediate layer and the gas barrier coating layer (collectively referred to as "coating layer" in the table). The heat drying of the gas barrier intermediate layer and the gas barrier coating layer was performed by attaching a heat label (manufactured by Micron Co., Ltd.) to the surface of the coating film before drying, checking the temperature after drying, and adjusting the oven temperature and line speed to achieve the desired temperature and drying time. The drying temperatures shown in Table 1 are the temperatures of the heat labels.

[0074] [Table 1]

[0075] <Measurement of composite modulus and hardness> In the gas barrier films obtained in the examples and comparative examples, the composite modulus and hardness of the gas barrier coating layer were measured by the following method. The measuring apparatus used was a Hysitron TI-Premier (product name) manufactured by Bruker Japan Co., Ltd., equipped with a nanoDMA III transducer (product name) as the transducer. The indenter used was a Berkovich-type diamond heating indenter TI-0283 (product name) with a tip opening angle of 142.3°. The measurement temperature was controlled using a heating stage xSol400 (product name) manufactured by Bruker Japan Co., Ltd. The heating rate during temperature control was set to 20°C / min, and after the heating stage reached the desired temperature, it was held for 10 minutes before measurement. In addition, fused silica, which would serve as a standard sample, was tested in advance to calibrate the relationship between contact depth and contact projected area. For the nanoindentation method, the measurement conditions were as follows: in a quasi-static test, the material was indented to a depth of 30 nm at an indentation speed of 30 nm / second, held at the maximum depth for 1 second, and then unloaded at a speed of 30 nm / second. The composite modulus and stiffness were calculated using the Oliver-Pharr method by analyzing the unloading curve results in the 60-95% range relative to the maximum load during unloading. These results are shown in Table 2.

[0076] * Measurement > The L of the gas barrier film obtained in the examples and comparative examples * a * b * Color coordinate b in a color system * The color was measured using a colorimeter (manufactured by Suga Test Instruments Co., Ltd., product name: Colour Cute i) under the following conditions: C light 2-degree field of view. * If the value was 0.5 or less, it was determined that the yellow tint had been reduced. The results are shown in Table 2.

[0077] <Measurement of Water Vapor Transmission Rate (WVTR)> ​The water vapor transmission rate of the gas barrier films obtained in the examples and comparative examples was measured by the following method. First, a laminate film was prepared by bonding a 25 μm polyethylene terephthalate film to the gas barrier coating surface of the gas barrier films obtained in the examples and comparative examples using an acrylic urethane resin adhesive. The water vapor transmission rate of this laminate film was measured using a water vapor transmission rate measuring device (MOCON, product name: PERMATRAN-W 3 / 34) under conditions of 40°C and 90% relative humidity. Measurements were performed on the initial laminate film and on the laminate film after being stored for 1000 hours at 60°C and 90% relative humidity. The measurement method conformed to JIS K-7126, Method B (isobaric method), and the measured value was expressed in units of [g / m²]. 2 The data was expressed as [ / day]. The same measurement was performed three times, and the average value was used. The results are shown in Table 2.

[0078] <Exterior Evaluation> The gas barrier films obtained in the examples and comparative examples were visually inspected, and their appearance was evaluated based on the following evaluation criteria. The results are shown in Table 2. A: It's almost wrinkle-free and beautiful. B: There are some wrinkles, but they are few and not very noticeable. C: Has many deep wrinkles, defective.

[0079] [Table 2] [Explanation of symbols]

[0080] 7...Phosphor layer, 8...Phosphor, 9...Sealing resin, 11...Substrate, 13...First AlO x Vapor-deposited layer, 14...gas barrier intermediate layer, 15...first barrier layer, 23...second AlO x Vapor deposition layer, 24...gas barrier coating layer, 25...second barrier layer, 100...gas barrier film, 200...wavelength conversion sheet.

Claims

1. Substrate and first AlO ｘ A vapor-deposited layer, a gas barrier intermediate layer, and a second AlO ｘ The structure has a vapor-deposited layer and a gas barrier coating layer stacked in this order. The first AlO ｘ Evaporated layer and the second AlO ｘ The thickness of the deposited layer is 15 nm or less in all cases. The thickness of both the gas barrier intermediate layer and the gas barrier coating layer is 200 to 400 nm. The aforementioned gas barrier coating layer is a layer formed using a gas barrier coating layer forming composition containing 1,3,5-tris(3-trialkoxysilylalkyl) isocyanurate or its hydrolysate. The composite modulus of the gas barrier coating layer, as measured by nanoindentation, is 8.2 to 11 GPa at a measurement temperature of 25°C and 5 to 8 GPa at a measurement temperature of 60°C. A gas barrier film wherein the hardness of the gas barrier coating layer, as measured by nanoindentation, is 1.23 to 1.70 GPa at a measurement temperature of 25°C and 0.85 to 1.30 GPa at a measurement temperature of 60°C.

2. The substrate is the first AlO ｘ The gas barrier film according to claim 1, wherein the surface on the vapor-deposited layer side is plasma-treated.

3. The gas barrier film according to claim 1 or 2, wherein the gas barrier coating layer forming composition further contains at least one selected from the group consisting of a hydroxyl group-containing polymer compound, a metal alkoxide, a silane coupling agent other than 1,3,5-tris(3-trialkoxysilylalkyl) isocyanurate, and hydrolysates thereof.

4. A wavelength conversion sheet comprising a phosphor layer and a gas barrier film according to any one of claims 1 to 3 disposed on at least one surface of the phosphor layer.

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