JP2017040730A - Barrier film for light wavelength conversion member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a barrier film for a light wavelength conversion member having excellent oxygen and water vapor blocking properties, and suppressing color unevenness.SOLUTION: A barrier film for a light wavelength conversion member has an intermediate layer between a first film having a barrier layer on a substrate film having birefringence and a second film having birefringence, where one side of the first film different from the other side having the barrier layer formed thereon is in contact with the intermediate layer, and the intermediate layer is in contact with the second film.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a barrier film for an optical wavelength conversion member having excellent oxygen barrier properties and water vapor barrier properties, and suppressing color unevenness.

  Liquid crystal display devices are widely used in mobile phones, notebook computers, televisions, monitors, car navigation systems, etc., but in recent years, power saving, thinning, and color reproducibility of liquid crystal display devices have been improved. There is a strong demand.

  A liquid crystal display device incorporates a backlight as a light source, and light emitted from the backlight is displayed in full color using light of three colors through a filter that transmits red, green, and blue colors. However, because the spectrum of each color of red, green, and blue is broad, not only the colors of red, green, and blue, but also light of these intermediate colors is transmitted through the filter, causing the color reproducibility to deteriorate. It has become. Therefore, a method of obtaining a sharp color using an LED array using LEDs of red, green, and blue colors is known. However, since this method uses three colors of LEDs, manufacturing costs may increase. There is a problem that the color reproducibility is lowered with the use time because the deterioration speed of each LED is different. As another method for improving the color reproducibility, there is a method in which a blue LED is used as a primary light source and a part of the light is wavelength-converted into red or green. In particular, quantum dots, which are semiconductor fine particles of several nm to several tens of nm, are attracting attention as phosphors that can convert to a sharp wavelength spectrum and have low energy loss. Optical wavelength conversion in which these quantum dots are dispersed in a resin A wavelength conversion sheet including a layer has been proposed (Patent Documents 1 and 2).

Japanese Patent Laying-Open No. 2015-57640 Special table 2013-544018 gazette

  Quantum dots are attracting attention as a material that can be converted into a sharp wavelength spectrum and contribute to power saving because of low energy loss. However, since it has the property of being deteriorated by oxygen, water vapor, and heat, there has been a problem that the color purity is lowered as the quantum dots are deteriorated. Therefore, in order to prevent the deterioration of the quantum dots in the wavelength conversion sheet, a method of providing a barrier layer that does not transmit water vapor or oxygen to the light wavelength conversion layer including the quantum dots has been considered. However, when the barrier layer is directly provided on the light wavelength conversion layer, there is a problem that the quantum dots are deteriorated by heat when the barrier layer is provided. In addition, when a barrier film is bonded to the light wavelength conversion layer to improve the barrier property, there is a problem that color unevenness is likely to occur when the base material of the barrier film has birefringence.

  In view of these problems, the present invention relates to a barrier film for an optical wavelength conversion member having excellent oxygen barrier properties and water vapor barrier properties and suppressing color unevenness.

  The barrier film for a light wavelength conversion member of the present invention has an intermediate layer between a first film having a barrier layer and a second film having birefringence on a base film having birefringence, The side opposite to the barrier layer in one film is in contact with the intermediate layer, and the intermediate layer is in contact with the second film.

  That is, the barrier film for a light wavelength conversion member of the present invention preferably has a second film, an intermediate layer, a base film, and a barrier layer in this order.

  According to the present invention, it is possible to suppress the deterioration of quantum dots and to suppress color unevenness with excellent oxygen barrier properties and water vapor barrier properties. Furthermore, the light extraction property can be improved by disposing a light diffusion layer on the second film.

It is the schematic which shows an example of a structure of the barrier film for optical wavelength conversion members of this invention. It is the schematic which shows an example of a structure of the barrier film for optical wavelength conversion members which has a light-diffusion layer of this invention. It is the schematic which shows the light wavelength conversion member using the barrier film for light wavelength conversion members of this invention.

  Hereinafter, the barrier film for light wavelength conversion member of the present invention will be described in more detail with reference to the drawings.

  The barrier film for a light wavelength conversion member of the present invention has an intermediate layer between a first film having a barrier layer and a second film having birefringence on a base film having birefringence, The side opposite to the barrier layer in one film is in contact with the intermediate layer, and the intermediate layer is in contact with the second film.

  That is, it is preferable that the barrier film for a light wavelength conversion member of the present invention has the second film, the intermediate layer, the base film, and the barrier layer in this order (note that the base film and the barrier layer are combined here). This is the same as the first film).

  Moreover, it is more preferable that the barrier film for a light wavelength conversion member of the present invention has a light diffusion layer, a second film, an intermediate layer, a base film and a barrier layer in this order.

  Details of each component will be described below.

[Base film having birefringence]
The base film having birefringence (hereinafter sometimes simply referred to as “base film”) and the second film in the first film according to the present invention are not particularly limited as long as they have birefringence. Birefringence is a phenomenon in which when light enters an anisotropic medium, the refracted wave is split into two polarized waves, an ordinary ray and an extraordinary ray. The phase difference between the two polarized waves is called retardation, and it is known that a light interference color is generated depending on this value. Accordingly, when a film having birefringence is used in optical applications, color unevenness may occur. Therefore, the present invention succeeds in suppressing this color unevenness by using a plurality of films having birefringence. . The film having such birefringence according to the present invention preferably has a retardation (Re) represented by the following formula of 5 nm or more.

Re = Δn · d (1)
(In the formula (1), Δn is birefringence in the in-plane direction of the film at a wavelength λ = 590 nm, and d is the thickness (nm) of the film.)
When Re is less than 5 nm, the influence of birefringence is small, and color unevenness due to lamination may occur.

  Since the base film and the second film in the first film need to transmit and emit the wavelength-converted light, those having high light transmittance are preferable, and the total light transmittance is 90% or more. Is preferred.

  Specific examples of the base film and the second film in the first film are, for example, polyester films, and are typically represented by polyalkylene terephthalate represented by polyethylene terephthalate, polybutylene terephthalate, and the like, polyethylene-2,6-naphthalate, and the like. And polyalkylene naphthalate, copolyalkylene arylate, and the like. The base film may be an unstretched film, but a stretched film is preferable and a biaxially stretched film is particularly preferable from the viewpoint of heat resistance and thickness control.

  The thickness of the base film in the first film is preferably 5 μm or more and 50 μm or less, and more preferably 8 μm or more and 30 μm or less. If the thickness is less than 5 μm, the base film may lose heat during processing, or the handling may be lowered due to the lack of stiffness of the film. If it is thicker than 50 μm, it may be difficult to increase the processing speed for forming the barrier layer on the substrate film, and the production amount of one batch may be reduced, which may cause high costs.

  The thickness of the second film is preferably 30 μm or more and 300 μm or less, and more preferably 50 μm or more and 125 μm or less. When the thickness is less than 30 μm, the barrier film becomes thin, and the handling property may be lowered. When it is thicker than 300 μm, the rigidity becomes high and it becomes difficult to bond to the light wavelength conversion sheet, and it may be peeled off when the light wavelength conversion film is obtained.

  Furthermore, the difference in thickness between the base film and the second film in the first film is preferably 25 μm or more. When the difference in thickness between the base film and the second film in the first film is less than 25 μm, both the base film and the second film in the first film have the same rigidity and are difficult to bond. There is.

  The total thickness of the light wavelength conversion member barrier film is preferably 35 μm or more and 350 μm or less, and more preferably 50 μm or more and 150 μm or less. If it is thinner than 35 μm, the barrier film is not stiff and handling may be deteriorated. If it is thicker than 350 μm, the rigidity of the barrier film becomes high, and it may be difficult to bond it to the light wavelength conversion sheet.

  In addition, the base film surface and the second film surface in the first film have a corona treatment, an ion bombardment treatment, a solvent treatment, a surface roughening treatment, and an organic or inorganic substance or the like in order to improve adhesion. Pretreatment such as formation of an anchor coat layer composed of a mixture of the above may be performed. In addition, on the opposite side of the barrier layer and the light diffusion layer, which will be described later, a coating layer of organic matter, inorganic matter, or a mixture thereof is provided for the purpose of improving the slipperiness during winding of the film and reducing friction. Also good.

[Barrier layer]
The barrier layer in the first film according to the present invention is not particularly limited, and may be a layer containing an inorganic compound (hereinafter sometimes referred to as “inorganic compound layer”) or an organic layer. It is preferable to have an inorganic compound layer on one surface, and an organic layer may be further laminated on the inorganic compound layer. Such an inorganic compound layer and an organic layer may be a single layer or a plurality of layers.

The water vapor transmission rate of the barrier film for light wavelength conversion member in the present invention is preferably 0.5 g / m ² / day or less, more preferably 0.4 g / m ² / day or less, and the oxygen transmission rate is 0.5 cm ³ / m. ² / day / atm or less. When the water vapor transmission rate is larger than 0.5 g / m ² / day or the oxygen transmission rate is larger than 0.5 cm ³ / m ² / day / atm, water vapor or oxygen reaches the light wavelength conversion sheet described later. In some cases, the light wavelength conversion substance is deteriorated, the emission wavelength is changed, and the color reproducibility is lowered or the light intensity is lowered.

  Examples of inorganic compounds that can be used in the inorganic compound layer include metal oxides and metal nitrides. Examples of the metal oxide include aluminum oxide, magnesium oxide, titanium oxide, tin oxide, indium oxide alloy, silicon oxide, silicon oxynitride, and mixed oxides thereof. Examples of the metal nitride include aluminum nitride, titanium nitride, and silicon nitride. Can be illustrated. Among these, aluminum oxide, silicon oxide, and silicon oxynitride are preferable from the viewpoint of processing cost of vapor deposition film and gas barrier performance. There is no restriction | limiting in particular in the film forming method of these inorganic compound layers, For example, what is necessary is just to perform by well-known methods, such as vapor deposition and sputtering.

  The thickness of the inorganic compound layer is preferably 5 nm to 400 nm, more preferably 5 nm to 100 nm, and still more preferably 5 nm to 50 nm. If the thickness of the inorganic compound layer is less than 5 nm, the barrier property may not be sufficiently obtained. If the thickness is more than 400 nm, the light transmittance is lowered, or the residual stress after film formation is large and cracks are likely to occur. There is a case.

  The organic layer is formed using an organic compound having excellent barrier properties, such as polyvinyl alcohol, and compensates for defects such as pinholes and cracks generated in the inorganic compound layer, thereby further improving the barrier properties of the inorganic compound layer. Also good. As a preferable example of the organic layer, a mixture of a main agent containing an unsaturated nitrile (a), an unsaturated compound (b) having a hydroxyl group, and a curing agent (c) composed of a compound having an isocyanate group is used. Are formed. More preferably, the main agent is selected from the group consisting of unsaturated nitrile (a), unsaturated compound (b) having a hydroxyl group, unsaturated carboxylic acid ester, styrene, unsaturated carboxylic acid, unsaturated hydrocarbon and vinyl ester. It is comprised with the copolymer which makes a monomer the at least 3 component with one or more unsaturated compounds (d) selected.

  The organic layer is preferable because the barrier property increases as the polymer chains strongly aggregate in the structure. Therefore, the unsaturated nitrile (a) used for the main agent is preferably acrylonitrile having a highly polarized functional group. As for the compounding quantity of unsaturated nitrile, 10-30 mass% is preferable with respect to 100 mass% of the whole organic layer, More preferably, it is 10-25 mass%. When the amount of the unsaturated nitrile (a) is more than 30% by mass, the solubility of the main agent in an organic solvent is lowered, which may not only prevent an increase in molecular weight during polymerization but also make coating difficult. is there. Furthermore, it may become impractical because the film-forming property and transparency of the coating film are lowered. On the other hand, when the amount is less than 10 parts by mass, the effect of improving the gas barrier property of the barrier layer may be insufficient.

  The unsaturated compound (b) having a hydroxyl group used as a main component of the organic layer has a function of strongly aggregating polymer chains and strongly adhering to the inorganic compound layer. Examples of the unsaturated compound (b) having a hydroxyl group include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, 2 -Monomers of unsaturated compounds such as hydroxy vinyl ether, polyethylene glycol methacrylate, polypropylene glycol monoacrylate and polypropylene glycol monomethacrylate. These unsaturated compounds having a hydroxyl group can be selected singly or in combination of two or more. Of these unsaturated compounds having a hydroxyl group, 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate is preferable because good polymerization stability is obtained and reactivity with an isocyanate group is good. Ethyl methacrylate is particularly preferred. The compounding amount of the unsaturated compound (b) having a hydroxyl group is preferably 30 to 70% by mass, more preferably 50 to 70% by mass with respect to 100% by mass of the entire organic layer. When the blending amount of the unsaturated compound (b) having a hydroxyl group is less than 30% by mass, the cohesive force between the resin chains derived from the hydroxyl group does not work sufficiently, and the barrier property may be insufficient. On the other hand, when the compounding amount of the unsaturated compound (b) having a hydroxyl group is more than 70% by mass, it is necessary to increase the compounding amount of the curing agent because the number of hydroxyl groups increases in the main agent. The isocyanate group is likely to remain unreacted and may cause a problem such as blocking. Furthermore, since the content ratio of the above-mentioned (a) and (c) described later decreases, the gas barrier property improving effect may be reduced, or the film forming property of the coating film may be reduced.

  As a mass ratio of the unsaturated nitrile (a) and the unsaturated compound (b) having a hydroxyl group, (a) :( b) is preferably 10:70 to 30:30. More preferably, it is 20: 50-30: 50.

  In the present invention, at least one unsaturated compound (d) selected from the group consisting of an unsaturated carboxylic acid ester, styrene, an unsaturated carboxylic acid, an unsaturated hydrocarbon, and a vinyl ester preferably used for the main agent is an unsaturated carboxylic acid. As acid esters, methyl methacrylate, methyl acrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, t- Examples include butyl acrylate, t-butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, itaconic acid, crotonic acid, and fumaric acid. Examples of other monomers include styrene, α-methylstyrene, butadiene, ethylene, vinyl acetate and the like. Of these, unsaturated carboxylic acid esters are preferred. Of unsaturated carboxylic acid esters, methyl methacrylate and methyl acrylate are particularly preferable, and methyl methacrylate is more preferable.

  3-60 mass% is preferable with respect to 100 mass% of the whole organic layer, and, as for the compounding quantity of (d), 5-40 mass% is more preferable. When the blending amount of (d) is more than 60% by mass, the relative amount of the unsaturated nitrile (a) and the unsaturated compound (b) having a hydroxyl group in the main agent decreases, and the gas barrier property is not sufficiently exhibited. In some cases, the strength of the coating film and the resistance to hot water treatment due to insufficient cross-linking structure may be insufficient.

  At least one unsaturated compound selected from the group consisting of an unsaturated nitrile (a), an unsaturated compound having a hydroxyl group (b), an unsaturated carboxylic acid ester, styrene, an unsaturated carboxylic acid, an unsaturated hydrocarbon, and a vinyl ester The mass ratio of (d) is preferably (a) + (b) :( d) = 40: 60 to 97: 3. More preferably, (a) + (b) :( d) = 60: 40 to 80:20.

  As the curing agent (c) for curing the organic layer, a curing agent composed of a compound having an isocyanate group is preferable. Examples of the compound having an isocyanate group include aromatic diisocyanates, araliphatic diisocyanates, alicyclic diisocyanates, and aliphatic diisocyanates. Examples of aromatic diisocyanates that can be used include m- or p-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,5-naphthalene diisocyanate (NDI), 4,4′-, 2,4′- or 2, Examples include 2'-diphenylmethane diisocyanate (MDI), 2,4- or 2,6-tolylene diisocyanate (TDI), 4,4'-diphenyl ether diisocyanate, and the like. Examples of the araliphatic diisocyanate that can be used include 1,3- or 1,4-xylylene diisocyanate (XDI), 1,3- or 1,4-tetramethylxylylene diisocyanate (TMXDI), and the like. Examples of alicyclic diisocyanates that can be used include 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate; IPDI), 4,4 ′. -, 2,4'- or 2,2'-dicyclohexylmethane diisocyanate (hydrogenated MDI), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,3- or 1,4-bis (Isocyanate methyl) cyclohexane (hydrogenated XDI) and the like can be exemplified. Examples of the aliphatic diisocyanate that can be used include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-, 2,3-, or 1,3- Examples include butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate. These include urethane-modified products, allophanate-modified products, urea-modified products, biuret-modified products, uretdione-modified products, uretoimine-modified products, isocyanurate-modified products, and carbodiimide-modified products. These may be a single product or a mixture.

  Furthermore, you may use the partial condensate of the isocyanate compound illustrated above, the compound etc. which have a hydroxyl group, 1 type of various derivatives, or these 2 or more types. For example, a wide range of diols from various low molecular weight diols to oligomers, and partial condensates with trifunctional or higher functional polyols as required.

  In the present invention, the blending ratio of the main agent and the curing agent constituting the organic layer is not particularly limited, but if the amount of the curing agent is too small, the crosslinking reaction that occurs between the main agent and the coating becomes insufficient. However, not only does poor curing occur, but the coating film strength does not sufficiently develop, and there are cases where the resistance to hot water treatment, adhesion to the substrate film, and the like are insufficient. Moreover, when there are too many compounding quantities of a hardening | curing agent, it will not only cause a blocking, but it may cause inconvenience in post-processing and the like due to an excess isocyanate compound moving to another layer.

  In addition, a compound having two or more carboxylic acid groups or one or more carboxylic anhydride groups or a silane coupling agent is added to the organic layer in order to improve the adhesion between the inorganic compound layer and the organic layer. May be.

  The thickness of the organic layer is preferably 0.1 μm or more and 3.0 μm or less, more preferably 0.2 μm or more and 2.0 μm or less. If the thickness is less than 0.1 μm, the gas barrier property may be insufficient, or defects such as film breakage or repellency may easily occur during coating. On the other hand, if it is thicker than 3.0 μm, the film may curl due to the stress of the obtained film.

  In the present invention, an overcoat layer may be further provided on the barrier layer. The overcoat layer is preferably provided for the purpose of protecting the barrier layer, adhesion to the light wavelength conversion sheet, and the like. The overcoat layer is, for example, polyethylene, linear polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-methacrylic acid copolymer, ethylene-methacrylic acid, ester copolymer, ethylene-acrylic acid copolymer, It is formed of a plastic material such as an ethylene-acrylic acid ester copolymer, an acrylic resin, a polyurethane resin, and a metal cross-linked product thereof. The thickness is appropriately determined according to the purpose, but is generally 0.05 μm or more and 200 μm or less.

  In the present invention, as long as the characteristics of the barrier layer are not impaired, a heat stabilizer, an antioxidant, a reinforcing agent, a pigment, a deterioration preventing agent, a weathering agent, a flame retardant, a plasticizer, a release agent, a lubricant, and the like. May be added.

[Middle layer]
The barrier film for a light wavelength conversion member of the present invention has an intermediate layer between the first film and the second film. The intermediate layer includes an adhesive layer or an adhesive layer for integrating the first film and the second film. Examples of the material for forming the adhesive layer include acrylic resin, silicone resin, urethane resin, polyvinyl butyral, and ethylene-vinyl acetate. Examples of the material for the adhesive layer include bisphenol A type epoxy resin and tetrahydroxyphenylmethane type epoxy resin. And (di) enes such as polyisoprene and poly-1,2-butadiene. Examples of the adhesive resin include polyester resins, polyurethane resins, acrylic resins, epoxy resins, and silicone resins. These resins may be used alone, or two or more copolymers or a mixture thereof may be used. Among these, acrylic resins are preferable because they are excellent in reliability such as water resistance, heat resistance, and light resistance, and have good adhesion and transparency.

  The intermediate layer has one surface in contact with the opposite side of the first film to the barrier layer and the other surface in contact with the second film. When the opposite side of the barrier layer of the first film is in contact with the intermediate layer, the optical wavelength conversion sheet and the barrier layer are close to each other when the optical wavelength conversion member is configured, and the optical wavelength conversion sheet is efficiently protected from oxygen and water vapor. can do. Furthermore, when the below-mentioned light-diffusion layer exists in a 2nd film, it is preferable that an intermediate | middle layer touches the surface on the opposite side to the light-diffusion layer of a 2nd film. In the case where a light diffusion layer is provided for the purpose of eliminating a decrease in extraction efficiency due to light reflected through the light wavelength conversion member being totally reflected at the interface with the air layer, the light diffusion layer and the intermediate layer are If contacted, the light diffusion function may not function sufficiently.

  The intermediate layer may contain particles. This is because when the intermediate layer contains particles, a light diffusion function can be imparted or the film strength of the intermediate layer can be improved by a difference in refractive index between the particles and a material other than the particles constituting the intermediate layer.

  The shape of the particles contained in the intermediate layer may be, for example, a flat shape such as a star shape, a leaf shape or a disk shape, a rhombus shape, a rectangular shape, a needle shape, a confetti shape, an aspheric shape such as an indeterminate shape, It means not only a true sphere but also a particle whose cross-sectional shape is surrounded by a curved surface such as a circle, an ellipse, a substantially circle, a substantially ellipse, etc.). Further, the particles having these shapes may be porous, non-porous, or hollow, and particles having different particle shapes may be mixed, but a spherical shape in which scattered light is uniformly scattered is preferable. The material of the particles contained in the intermediate layer may be either an organic compound or an inorganic compound and is not particularly limited. Further, particles of different materials may be mixed and used.

  An organic compound is preferable as the material of the particles contained in the intermediate layer, and as such an organic compound, a resin mainly composed of a high-melting cross-linked polymer component is preferable, for example, a polyester resin, a polyamide such as benzoguanamine, and the like. Resin particles, polyurethane resin, acrylic resin, methacrylic resin, polyamide resin, polyethylene resin, polypropylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, fluorine resin, silicone resin, etc. . These resins may be used alone, or two or more copolymers or a mixture thereof may be used.

  Examples of the inorganic compound used when applying the inorganic compound as the material of the particles contained in the intermediate layer include calcium carbonate, magnesium carbonate, zinc carbonate, titanium oxide, zinc oxide, cerium oxide, magnesium oxide, barium sulfate, Examples thereof include zinc sulfide, calcium phosphate, silica, alumina, mica, titanium mica, talc, clay, kaolin, lithium fluoride, and calcium fluoride.

  The average particle size of the particles contained in the intermediate layer is preferably from 0.1 μm to 100.0 μm, more preferably from 0.5 μm to 50.0 μm, and even more preferably from 1.0 μm to 30.0 μm. When the average particle size is smaller than 0.1 μm, the effect of containing particles is hardly exhibited, and the light diffusibility may be lowered. On the other hand, when the average particle diameter is larger than 100.0 μm, the appearance may be deteriorated. Here, the particle diameter is the number average particle diameter, and is the number average value of the particle diameters.

  1-70 mass% is preferable, as for content of the particle | grains contained in an intermediate | middle layer, 1-50 mass% is more preferable, 1-40 mass% is preferable, More preferably, it is 1-20 mass%. When the content of the particles is less than 1% by mass, the effect of containing the particles is hardly exhibited, and the light diffusibility may not change. On the other hand, when the content of the particles exceeds 70% by mass, unevenness is generated on the surface, making it difficult to bond the films together, or the adhesive force is lowered and the film is easily peeled off. It may be damaged. The particle content referred to here is the content of particles when the entire intermediate layer is 100% by mass.

  The refractive index difference between the resin forming the intermediate layer and the particles is preferably 0.05 to 0.5, and more preferably 0.05 to 0.3. If the difference in refractive index is less than 0.05, light diffusibility may not be obtained, and if the difference in refractive index is greater than 0.5, the internal diffusion is too large and the total light transmittance decreases, As a result, the extraction efficiency may decrease. The intermediate layer can further contain additives such as a curing agent and a crosslinking agent.

  The thickness of the intermediate layer is not particularly limited, but is preferably 0.3 μm or more and 70 μm or less. When the thickness is less than 0.3 μm, it may be difficult to bond the films together. When the thickness is more than 70 μm, the thickness of the entire barrier film may be increased, which may be contrary to the thinning of the display device.

[Light diffusion layer]
A light diffusion layer can be provided on the second film. The light diffusion layer is for improving the extraction efficiency of light transmitted through the barrier film, and the configuration is not particularly limited. For example, the light diffusion layer is provided on the opposite surface of the second film in contact with the intermediate layer. A light diffusing layer containing particles and a light diffusing layer having an uneven shape are preferable.

  The light diffusion layer containing particles contains a resin and particles, and the resin is not particularly limited, but a resin mainly composed of an organic component is preferable, for example, a polyester resin, a polyurethane resin, an acrylic resin, a methacrylic resin, a polyamide resin, a polyethylene resin. , Polypropylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyvinyl acetate resin, fluorine resin and the like. Here, the resin mainly composed of an organic component means a resin containing 60% by mass or more of the organic component in the resin, and is more preferably a resin containing 80% by mass or more of the organic component (hereinafter, the same definition is used). ). These resins may be used alone, or two or more copolymers or a mixture thereof may be used. Of these, polyester resins, polyurethane resins, acrylic resins or methacrylic resins are preferably used because of their excellent heat resistance, appearance, and particle dispersibility.

  The shape of the particles contained in the light diffusion layer can be selected from the same group as the shape of the particles contained in the intermediate layer, but is preferably spherical. Since the particle shape is spherical, the angle of the extracted light can be more easily concentrated in the front direction, and a display device having a bright front direction can be obtained.

  The average particle size of the particles used for the light diffusion layer is preferably 0.3 μm or more and 100.0 μm or less, more preferably 0.5 μm or more and 50.0 μm or less, and further preferably 1.0 μm or more and 30.0 μm or less. When the average particle diameter is smaller than 0.3 μm, the optical behavior due to the unevenness provided in the light diffusion layer by the particles changes depending on the wavelength, and thus color misregistration may occur. On the other hand, when the average particle diameter of the particles is larger than 100.0 μm, the appearance may be deteriorated. Moreover, since the particle diameter of the particle | grains used for a light-diffusion layer tends to provide the unevenness | corrugation by particle | grains on the light-diffusion layer surface, it is preferable that it is larger than the average thickness of a light-diffusion layer. Here, the particle diameter is the number average particle diameter, and is the number average value of the particle diameters.

  It is preferable that the content rate of the particle | grains used for a light-diffusion layer is 20-80 mass%, 30-80 mass% is more preferable, 40-80 mass% is further more preferable. When the content is less than 20%, unevenness formed on the surface is not sufficient, and the effect of adding particles may not be sufficiently obtained. On the other hand, if it exceeds 80%, the appearance may deteriorate. The particle content referred to here is the ratio of the mass of the particles to the total mass of the substances constituting the light diffusion layer.

  The thickness of the light diffusion layer is not particularly limited, but is preferably from 0.3 μm to 30 μm, more preferably from 1 μm to 20 μm, and most preferably from 3 μm to 10 μm. When the thickness is smaller than 0.3 μm, the appearance is deteriorated, and when it is larger than 30 μm, the economy may be inferior. Further, when the surface layer is uneven due to the contained particles, light is scattered and the front luminance is improved. Therefore, the thickness of the light diffusion layer is preferably about a fraction of the particle diameter of the contained particles.

  The method for providing the light diffusion layer containing particles is not particularly limited, and various coating methods such as gravure coating, roll coating, die coating, spin coating, reverse coating, bar coating, screen coating, blade coating, air knife coating, and dipping. Can be used. Moreover, you may apply | coat at the time of manufacture of the film used as a base material, and you may apply | coat by another process, after winding up the film used as a base material after film forming.

  A known method such as imprinting, etching, or self-organization patterning can be used for the light diffusing layer having an uneven shape. The patterning shape may be a regular arrangement or a random arrangement.

[Light wavelength conversion sheet]
The light wavelength conversion sheet is a sheet that converts light from a light source into light having a longer wavelength and emits it. The light wavelength conversion sheet preferably contains a fluorescent pigment, a fluorescent dye, or a fluorescent material for converting the wavelength of light, and the fluorescent material is preferably a quantum dot. Quantum dots have high wavelength conversion efficiency and a narrow half-value width of the emitted light spectrum, so that color reproducibility can be kept good, and are particularly preferably used for display applications. Quantum dots are, for example, fluorescent fine particles having a diameter of several nanometers to several tens of nanometers, and have a feature that the wavelength of emitted light changes depending on the particle diameter. The quantum dots are generated from any suitable material, preferably an inorganic material, more preferably an inorganic conductor or semiconductor material. For example, any type of semiconductor is included, including II-IV, III-V, IV-VI, and IV semiconductors, but any known semiconductor can be used.

  The light wavelength conversion sheet preferably contains a binder for dispersing the fluorescent material. As the binder, a material capable of transmitting light from a light source and light emitted after being converted into light is preferably used. Examples of suitable binders include, but are not limited to, various polymer resins such as epoxy resins, acrylic resins, polyolefin resins, polyurethane resins, silicone resins, styrene resins, and polyester resins. Absent.

  In addition, the fluorescent substance contained in these light wavelength conversion sheets may be only 1 type, or may be 2 or more types.

[Light wavelength conversion member]
The barrier film for light wavelength conversion members according to the present invention can be used for a light wavelength conversion member. That is, the light wavelength conversion member of the present invention preferably has a light wavelength conversion sheet and a barrier film for a light wavelength conversion member. The light wavelength conversion member is excited by the light from the light source, converts the light from the light source into light having a wavelength different from the wavelength from the light source, and emits the light. Including.

  When the light wavelength conversion sheet used for the light wavelength conversion member includes quantum dots, the wavelength of light emitted due to deterioration of the quantum dots due to water vapor or oxygen may change or the intensity may decrease. Therefore, in order to prevent deterioration of the light wavelength conversion sheet due to water vapor or oxygen, the light wavelength conversion member is preferably laminated in the order of barrier film / light wavelength conversion sheet / barrier film. Furthermore, in order to protect the light wavelength conversion sheet, the barrier layer of the barrier film is preferably laminated on the side close to the light wavelength conversion sheet.

[Backlight unit]
The light wavelength conversion member thus obtained can be used for a backlight unit. The backlight unit has at least a primary light source and a light wavelength conversion member. The primary light source is not particularly limited as long as it is a wavelength that can be used for wavelength conversion of the light wavelength conversion member. For example, as a preferable embodiment, a blue LED is used as the primary light source, and blue light is converted into red and green. The thing using the light wavelength conversion member which has a light wavelength conversion sheet can be illustrated.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to these Examples.

(1) Measurement of retardation of base film and second film The retardation of the base film and the second film was measured using an automatic birefringence meter (KOBRA-21ADH manufactured by Shin-Oji Paper Co., Ltd.).

(2) Evaluation of barrier properties The water vapor transmission rate was measured at a temperature of 40 ° C. and a humidity of 90% RH under the conditions of a water vapor transmission rate measurement device (model name “Permatran” (registered trademark) manufactured by MOCON, USA. ) W3 / 31) and measured based on the method B (infrared sensor method) described in JIS K7129 (2000 version).

  Oxygen permeability is measured at a temperature of 23 ° C. and a humidity of 0% RH using an oxygen permeability measuring device (model name “Oxytran” (registered trademark) (OXTRAN 2/20)) manufactured by MOCON, USA. , Measured according to the B method (isobaric method) described in JIS K7126 (2000 version).

  Ranking was made as follows from the respective values of water vapor transmission rate and oxygen transmission rate.

A: Water vapor transmission rate of less than 0.5 g / m ² / day and oxygen transmission rate of less than 0.5 cm ³ / m ² / day / atm B: Water vapor transmission rate of 0.5 g / m ² / day or more and / or oxygen Transmittance 0.5 cm ³ / m ² / day / atm or more.

(3) Production of Light Wavelength Conversion Member With reference to Japanese Patent Application Laid-Open No. 2013-544018, a light wavelength conversion sheet that converts red and green light by primary light of a blue LED was obtained. One barrier film for a light wavelength conversion member was bonded to each of both surfaces of the obtained light wavelength conversion sheet so that the barrier layer was in contact with the light wavelength conversion sheet. One of the films to be bonded to both surfaces of the light wavelength conversion sheet was the A side, and the other was the B side.

(4) Evaluation of Color Unevenness A surface light emitter emitting blue light was lit for 30 minutes after placing a light wavelength conversion member described later, and sensitivity evaluation was performed with five people. The case where the entire surface looks uniform color is good, the case where color unevenness is visible is regarded as defective, and the evaluation is A when the quality is 3 or more and the evaluation B when the quality is 3 or more.

The configuration of the surface light emitter is as follows.
Size: 7 inches Primary light source: Blue LED with wavelength 455nm
Member structure: reflection film / diffuser plate / light wavelength conversion member / two prism sheets.

(5) Evaluation of light extraction property After the surface light emitter on which the members are arranged is lit for 30 minutes in the same manner as the color unevenness evaluation, the front surface of the light emitter is obtained using a two-dimensional color luminance meter CA-200 manufactured by Konica Minolta Sensing Co., Ltd. The luminance in the direction was measured, and the light extraction property was evaluated according to the following criteria.

S: Front luminance is 7,400 cd / m ² or more A: Front luminance is 7,350 cd / m ² or more and less than 7,400 cd / m ² B: Front luminance is 7,250 cd / m ² or more and less than 7,350 cd / m ² C: Front luminance is less than 7,250 cd / m ² .

[Example 1]
A biaxially stretched polyethylene terephthalate film (“Lumirror” (registered trademark) P60, manufactured by Toray Film Processing Co., Ltd.) having a thickness of 12 μm is used as the base film of the first film, and an inorganic compound layer and an organic layer are formed on the surface To provide a barrier layer.

  The inorganic compound layer was vapor-deposited with a thickness of 15 nm using a vacuum vapor deposition machine.

  The copolymer resin used in the organic layer is composed of acrylonitrile as the unsaturated nitrile (a), 2-hydroxyethyl methacrylate as the unsaturated compound (b) having a hydroxyl group, unsaturated carboxylic acid ester, styrene, unsaturated carboxylic acid, Methyl methacrylate is used as one or more unsaturated compounds (d) selected from the group consisting of unsaturated hydrocarbons and vinyl esters, and these are represented by mass ratio (a) / (b) / (d) = 20 / 50/30 was mixed and copolymerized to obtain a main agent. The obtained main agent was dissolved in a mixed solvent of propyl acetate, propylene glycol monomethyl ether and n-propyl alcohol so that the solid content concentration was 30% by mass to obtain a copolymer resin. 10.0 parts by mass of the obtained copolymer resin, 2.5 parts by mass of an isocyanate curing agent Dick Dry X-75 manufactured by Dainippon Ink and Chemicals, Ltd., and 20.1 parts by mass of methyl ethyl ketone were stirred for 30 minutes to obtain a solid content concentration. A coating liquid for 15% by mass organic layer was obtained. This coating solution was applied on the aluminum oxide vapor deposition layer. The film was dried at 140 ° C. for 30 seconds to form an organic layer having a thickness of 0.8 μm as a barrier layer to obtain a first film.

  A biaxially stretched polyethylene terephthalate film (“Lumirror” (registered trademark) U34 manufactured by Toray Industries, Inc.) having a thickness of 50 μm was used as the second film.

  For the intermediate layer, an acrylic pressure-sensitive adhesive TD43A (manufactured by Yodogawa Paper Mill) is used, and the first film / intermediate layer / second film is arranged in this order so that the barrier layer of the first film is opposite to the intermediate layer. It bonded so that it might become, and the barrier film a for light wavelength conversion members was obtained.

[Example 2]
The first film was prepared in the same manner as the barrier film a.

  A biaxially stretched polyethylene terephthalate film (“Lumirror” (registered trademark) U34 manufactured by Toray Industries, Inc.) having a thickness of 50 μm was used as the base film of the second film, and a light diffusion layer was provided by the following method. Acrylic resin “Acridic” (registered trademark) A-165 (manufactured by DIC Corporation) 9.0 g and toluene 15.0 g, crosslinked polymethyl methacrylate particles “TECHPOLYMER” (registered trademark) MBX series, MBX-5 (Sekisui A light diffusion coating solution was prepared by mixing 6.0 g of a number average particle size of 5.0 μm manufactured by Seiko Co., Ltd. A light diffusing coating solution was applied to one surface of the base film of the second film, and then heated and dried at 120 ° C. for 1 minute to provide a light diffusing layer having a thickness of 5 μm.

  The intermediate layer uses an acrylic pressure-sensitive adhesive TD43A (manufactured by Yodogawa Paper Mill) so that the barrier layer of the first film is opposite to the intermediate layer, and the light diffusion layer of the second film is the intermediate layer. Bonding was performed so that the first film / intermediate layer / second film were in this order so as to be on the opposite side, to obtain a barrier film b for light wavelength conversion member.

[Example 3]
The same film as the barrier film a was used for the first film and the second film.

  The intermediate layer is made of 100.0 g of acrylic adhesive SK Dyne 811L (manufactured by Soken Chemical Co., Ltd.), 1.5 g of isocyanate curing agent D-90 (manufactured by Soken Chemical Co., Ltd.), epoxy particle “Trepearl” (registered trademark) EP-B (Toray Industries, Inc., number average particle size 5.5 μm) 2.9 g was mixed to prepare a coating agent. The above coating agent was applied to one side of the second film so as to have a thickness of 20 μm, and then dried at 100 ° C. for 2 minutes to form an intermediate layer. Then, it bonded with the 1st film and obtained the barrier film c.

[Example 4]
A barrier film d was obtained in the same manner as the barrier film b except that the intermediate layer was the same as the barrier film c.

[Comparative Example 1]
The first film of the barrier film a was used as the barrier film e.

[Comparative Example 2]
The first film was the same as the first film of the barrier film a. A 60 μm thick triacetyl cellulose film (4UA manufactured by Konica Minolta) was used as the second film.

  For the intermediate layer, an acrylic pressure-sensitive adhesive TD43A (manufactured by Yodogawa Paper Mill) is used, and the first film / intermediate layer / second film is arranged in this order so that the barrier layer of the first film is opposite to the intermediate layer. It bonded so that it might become, and the barrier film f for light wavelength conversion members was obtained.

[Comparative Example 3]
A film g was obtained in the same manner as the barrier film a except that a biaxially stretched polyethylene terephthalate film having a thickness of 12 μm (“Lumirror” (registered trademark) P60 manufactured by Toray Film Processing Co., Ltd.) was used as the first film.

[Example 1 ']
A barrier film a was bonded to both surfaces A and B of the light wavelength conversion sheet to obtain a light wavelength conversion member.

[Example 2 ']
A barrier film a was bonded to the A surface of the light wavelength conversion sheet, and a barrier film b was bonded to the B surface to obtain a light wavelength conversion member. The barrier film b was bonded so that the barrier layer of the first film was in contact with the light wavelength conversion sheet.

[Example 3 ']
A barrier film c was bonded to both surfaces A and B of the light wavelength conversion sheet to obtain a light wavelength conversion member.

[Example 4 ']
A barrier film a was bonded to the A surface of the light wavelength conversion sheet, and a barrier film d was bonded to the B surface to obtain a light wavelength conversion member. The barrier film d was bonded so that the barrier layer of the first film was in contact with the light wavelength conversion sheet.

[Comparative Example 1 ']
A barrier film e was bonded to both A and B of the light wavelength conversion sheet to obtain a light wavelength conversion member.

[Comparative Example 2 ']
A barrier film f was bonded to both surfaces A and B of the light wavelength conversion sheet to obtain a light wavelength conversion member.

[Comparative Example 3 ′]
The film g was bonded together on both the A and B sides of the light wavelength conversion sheet to obtain a light wavelength conversion member.

1. 1. Barrier film First film3. 3. Base film in the first film 4. Barrier layer Second film 6. Intermediate layer 7. 7. Light diffusion layer Optical wavelength conversion sheet

Claims (5)

An intermediate layer between a first film having a barrier layer on a base film having birefringence and a second film having birefringence, on the opposite side of the first film from the barrier layer; A barrier film for a light wavelength conversion member, in contact with the intermediate layer, and in contact with the intermediate layer and the second film. The barrier film for a light wavelength conversion member according to claim 1, wherein the second film has a light diffusion layer on the side opposite to the side in contact with the intermediate layer. The barrier film for optical wavelength conversion members according to claim 1 or 2, wherein the intermediate layer contains particles. The light wavelength conversion member which has a light wavelength conversion sheet and the barrier film for light wavelength conversion members in any one of Claims 1-3. A backlight unit comprising the light wavelength conversion member according to claim 4 and a primary light source.

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