JP2018124367A - Film for organic electroluminescence display device sand laminate sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film that, when adopted for organic electroluminescence display devices, excels in flatness when an elastic and curable resin is formed, and a laminate sheet having a curable resin layer in the film.SOLUTION: Provided is a film for organic electroluminescence display devices, in which the bending hysteresis 2HB obtained from longitudinal and lateral bending tests are both 0.01 gf cm/cm to 0.04 gf cm/cm inclusive. Also provided is a laminate sheet for organic electroluminescence display devices having a layer that contains a curable resin on at least one side of the film for organic electroluminescence display devices.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a film for an organic electroluminescence display device and a laminated sheet, and can be particularly suitably used as a cover film for an organic electroluminescence display device by controlling the bending hysteresis 2HB in a bending test to a specific range. The present invention relates to a film and a laminated sheet.

  In recent years, an image display device using a self-luminous body called an organic light emitting diode (hereinafter referred to as an “organic electroluminescence display device”) has been put into practical use. Since this organic electroluminescence display device uses a self-luminous body as compared with a conventional liquid crystal display device, it is not only superior in terms of visibility and response speed, but also an auxiliary illumination device such as a backlight. Therefore, the display device can be made thin and flexible. For this reason, the development of a flexible display device that can be folded and rolled is accelerating, and the cover film that prevents the display device surface from being scratched is also required to have bending resistance.

  For example, as a technique for improving scratch resistance for an image display device, a hard coat film in which a hard coat layer is laminated on both surfaces of a base material including a polyester film has been proposed (for example, Patent Document 1). Moreover, an antireflection film in which an antireflection layer is provided on at least one surface of a flexible transparent resin film including a polyester film has been proposed for flexible display devices (for example, Patent Document 2).

Japanese Patent Laying-Open No. 2015-61750 Japanese Patent Laid-Open No. 2006-75869

  However, the film used for the image display device described in Patent Document 1 and Patent Document 2 is characterized by a hard coat layer and an antireflection layer, and the film serving as a base material does not consider flex resistance. Application to organic electroluminescence display devices has been difficult. Moreover, if the flex resistance of the film is improved, a new problem may arise that the flatness of the film when a curable resin layer such as a hard coat layer is applied to the film is deteriorated as a scratch-resistant layer. all right.

  Accordingly, an object of the present invention is to eliminate the above-mentioned problems, and when applied for an organic electroluminescence display device, a flat surface that is favorable when a curable resin such as a bending resistance and a hard coat layer is provided. It is to provide a film that can achieve both properties.

The present invention employs the following means in order to solve such problems.
(1) The bending hysteresis 2HB obtained from the bending test in the longitudinal direction and the width direction is both 0.01 gf · cm / cm and 0.04 gf · cm / cm.
(2) The b value obtained from the spectral color difference meter is 2.0 or less and the total light transmittance is 90% or more.
(3) longitudinal and flexural stiffness in the width direction are both 0.01gf · ^cm 2 · ^cm or more 0.1gf · ^cm 2 · ^cm or less.
(4) Variation in orientation angle within a range of 10 cm in the longitudinal direction of the film and 20 cm in the width direction is within 5 °.
(5) At least 150 ° C. heat shrinkage in the width direction is 1% or less, and 150 ° C. heat shrinkage in the longitudinal direction is within a range of −2% or more and 2% or less with respect to the 150 ° C. heat shrinkage in the width direction. There is.
(6) Polyester is the main constituent.
(7) Thickness direction refractive index is 1.5 or more.
(8) A laminated sheet having a layer containing a curable resin on at least one side of the film according to any one of (1) to (7).

  According to the present invention, a film excellent in flatness can be provided for an organic electroluminescence display device even when a bending resistance and a curable resin are provided, and can be suitably used particularly as a cover film on the front surface of the display device.

It is the schematic showing the test of the static flexibility by a mandrel test.

Below, the film for organic electroluminescence display devices concerning the present invention is explained in detail with an embodiment.
In the film for organic electroluminescence display device of the present invention, the bending hysteresis 2HB obtained from the bending test in the longitudinal direction and the width direction is both 0.01 gf · cm / cm and 0.04 gf · cm / cm. When the bending hysteresis 2HB is in the above range, the flatness when the curable resin layer is formed by static flexibility and hard coat is excellent. Here, the static bendability is evaluated by the method described in Evaluation Method (12) Static Flexibility by Mandrel Test, and the flatness when a curable resin layer is provided by a hard coat or the like is evaluated method (13) Curing It evaluates by the method as described in the external appearance after application of a functional resin. When the bending hysteresis exceeds 0.04 gf · cm / cm, the static flexibility deteriorates, and when it is less than 0.01 gf / cm / cm, the planarity when the curable resin layer is provided is inferior. The stress applied to the film when the static bending test is performed is compression on the inner side of the film fold, and tensile on the outer side of the fold. It is important to have. When controlling the bending hysteresis 2HB to 0.04 gf · cm / cm or less, for example, using a polyester film and increasing the plane orientation, the resistance to the surface direction, that is, the resistance to pulling outside the bending in static bending can be obtained. However, since it is accompanied by a decrease in refractive index in the thickness direction, resistance to compression inside the folding cannot be obtained, and the bending hysteresis 2HB may not be 0.04 or less. For this reason, in order to make the bending hysteresis 2HB 0.04 or less, it is preferable that the thickness direction refractive index is 1.5 or more. Further, from the viewpoint of obtaining bending resistance in the plane direction, the plane orientation coefficient indicating the degree of orientation in the plane direction, which is obtained by subtracting the refractive index in the thickness direction from the average refractive index in the longitudinal direction and the width direction, is 0.12 or more and 0.16 or less. It is preferable to control. The film surface direction, the refractive index in the thickness direction, and the plane orientation coefficient can be adjusted by the stretching temperature under the film forming conditions, the area stretching ratio, the heat treatment temperature after stretching, as well as the crystallinity of the resin. In the production method employing sequential biaxial stretching, in order to set the refractive index in the thickness direction to 1.5 or more, the stretching temperature in the longitudinal direction is not less than the glass transition temperature of the resin + 20 ° C. or less, and the stretching temperature in the width direction is the glass transition temperature of the resin. Examples of the method include 20 to 60 ° C., and an area stretching ratio of 8 to 12 times. Further, the higher the crystallinity, the smaller the refractive index in the thickness direction after stretching, and the crystallinity of the resin can be controlled by introducing a copolymer component. Taking polyethylene terephthalate as an example among polyesters, crystallinity can be lowered by copolymerizing isophthalic acid or cyclohexanedimethanol.
When the thickness of the film for organic electroluminescence display device of the present invention exceeds 35 μm, the curvature of the film in the static bending test is large, and the bending hysteresis 2HB may be 0.04 gf · cm / cm or more. It is important that the thickness of the entire film is 35 μm or less. Further, for a so-called soft resin such as silicon rubber, soft vinyl chloride, and biaxially stretched polypropylene film, the bending hysteresis may be 0.04 gf · cm / cm even if the film thickness is 35 μm or more. However, it is not preferable for a display application in which a concern of becoming less than 0.01 gf / cm / cm or a thin film is required. In addition, in resins other than polyester, when the bending hysteresis 2HB is 0.04 or less, some resins have a low bending hysteresis 2HB even if the mechanical strength is similar to that of a polyester film. The film using the film has a low bending hysteresis 2HB. It is presumed to be derived from the fact that there are few aliphatics as monomer structural units.
The film for organic electroluminescence display device of the present invention has a bending hardness of 0.01 gf · cm ² · in both longitudinal and width directions from the viewpoint of maintaining flatness when a curable resin layer such as a hard coat layer is applied. It is preferable that it is cm or more and 0.1 gf · cm ² · cm or less. It is preferably at most 0.04gf · ^cm 2 · ^cm or more 0.1gf · ^cm 2 · ^cm. In order to make it the said range, the method of making thickness of a film into 15 micrometers or more and 35 micrometers or less is mentioned. Moreover, since bending hardness can be raised by strengthening the orientation of a film, what is necessary is just to adjust thickness and orientation of a film according to a required characteristic.
The film for an organic electroluminescence display device of the present invention has a 150% heat shrinkage in the width direction of 1% from the viewpoint of dimensional stability during coating processing of a curable resin layer such as a hard coat layer and warpage suppression as a display device. It is preferable that the 150 ° C. heat shrinkage ratio in the longitudinal direction is −2% or more and 2% or less of the 150 ° C. heat shrinkage ratio in the width direction. By setting the heat shrinkage rate at 150 ° C. within the above range, it is possible to reduce the dimensional change in the drying process when laminating the layer containing the curable resin and the warpage when the display device is formed. Here, the heat shrinkage rate in the longitudinal direction and the width direction at 150 ° C. is carried out by the method described in Evaluation method (9) 150 ° C. heat shrinkage rate.

As a method in which the 150 ° C. heat shrinkage in the width direction is 1% or less and the 150 ° C. heat shrinkage in the longitudinal direction is in the range of −2% or more and 2% or less with respect to the 150 ° C. heat shrinkage in the width direction. The method for adjusting the film forming conditions, the method of performing off-annealing treatment, and the like can be mentioned. Examples of the film forming conditions include setting the heat treatment after stretching to a high temperature of 220 ° C. to 250 ° C. A method of relaxing the film by 3% or more during the heat treatment at 250 ° C. is preferable.
The film for an organic electroluminescence display device of the present invention preferably has a variation in orientation angle within a range of 10 cm × 20 cm within 5 degrees from the viewpoint of appearance as a display device. By setting the variation in the orientation angle within a range of 10 cm × 20 cm of the film to within 5 degrees, color unevenness when visually recognized as a display device can be suppressed, and good appearance can be achieved. Here, in the present invention, the variation in the orientation angle in the 10 cm × 20 cm range of the film was evaluated as shown in (10) Variation in the orientation angle in the 10 cm × 20 cm range. The variation in orientation angle in the 10 cm × 20 cm range of the film is more preferably within 4 degrees, and most preferably within 3 degrees.

In the film for an organic electroluminescence display device of the present invention, as a method of setting the variation in the orientation angle within a range of 10 cm × 20 cm within 5 degrees, for example, the heat treatment after stretching is divided into a plurality of zones and gradually increased. A method of temperature / temperature reduction or a method of fine stretching in the width direction in the heat treatment step is preferably employed. For example, it is slightly stretched 1% to 10%, preferably 3% to 10% in the width direction when the first half temperature of the heat treatment is 180 ° C. to 210 ° C., and 1% to the width direction when the second half temperature of the heat treatment is 200 ° C. More than 10%, preferably 3% to 10% fine stretching method.
The film for an organic electroluminescence display device of the present invention preferably has a film thickness of 13 μm or more and 35 μm or less, from the viewpoint of handling properties, scratch resistance, flex resistance, and flatness when a curable resin is applied, and 15 μm. More preferably, it is 35 μm or less, and most preferably 15 μm or more and 30 μm or less. Further, if the thickness is 35 μm or more, the bending hysteresis recovery property 2HB tends to be very high regardless of the material, and therefore it is preferably 35 μm or less.
When the film for an organic electroluminescence display device of the present invention is used for a display, the b value obtained from the spectral color difference meter is 2.0 or less and the total light transmittance is 90% or more. Is preferred. The b value can be adjusted to 2.0 or less by using polyester, polycarbonate, acrylic, polyamide, polyimide, nylon or the like, and the total light transmittance can be 90% or more. Especially, since the film for organic electroluminescent display devices of this invention makes polyester the main structural component, since it is cheap and productivity is high, it is preferable.
Examples of glycols or derivatives thereof that give polyester include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, Aliphatic dihydroxy compounds such as 1,6-hexanediol and neopentyl glycol, polyoxyalkylene glycols such as diethylene glycol, polyethylene glycol, polypropylene glycol and polytetramethylene glycol, alicyclics such as 1,4-cyclohexanedimethanol and spiroglycol Examples include dihydroxy compounds, aromatic dihydroxy compounds such as bisphenol A and bisphenol S, and derivatives thereof.

Examples of the dicarboxylic acid or its derivative that gives the polyester used in the present invention include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenoxyethanedicarboxylic acid, 5 -Aliphatic dicarboxylic acids such as sodium sulfone dicarboxylic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, 1,4-cyclohexanedicarboxylic acid and other alicyclic rings Oxycarboxylic acids such as aliphatic dicarboxylic acids and paraoxybenzoic acids, and derivatives thereof. Examples of dicarboxylic acid derivatives include dimethyl terephthalate, diethyl terephthalate, 2-hydroxyethyl methyl terephthalate, dimethyl 2,6-naphthalenedicarboxylate, dimethyl isophthalate, dimethyl adipate, diethyl maleate, and dimethyl dimer. An esterified product can be mentioned.
As a composition of polyester in this invention, it is preferable that 80 mol% or more of a glycol unit is a structural unit derived from ethylene glycol, More preferably, it is 85 mol% or more, Most preferably, it is 90 mol% or more. Further, 80 mol% or more of the dicarboxylic acid units are preferably structural units derived from terephthalic acid, more preferably 85 mol% or more, and most preferably 90 mol% or more.
The film for an organic electroluminescence display device of the present invention is preferably a laminated sheet for an organic electroluminescence display device having a layer containing a curable resin on at least one side. By having a layer containing a curable resin on at least one side, it is possible to enhance the effect of suppressing damage to an impact from the curable resin layer side.
Here, the curable resin refers to a resin that forms a crosslinked structure by being irradiated with heat or light and is cured. The curable resin is not particularly limited, but is preferably a thermosetting resin or an ultraviolet curable resin, and specifically, an organic silicone type, a polyol type, a melamine type, an epoxy type, a polyfunctional acrylate type, a urethane type. , An isocyanate-based resin, an organic-inorganic hybrid-based resin that is a composite material of an organic material and an inorganic material, and a silsesquioxane-based resin having a curable functional group. More preferred are epoxy-based, polyfunctional acrylate-based, organic-inorganic hybrid-based, and silsesquioxane-based resins. More preferred are polyfunctional acrylate-based, organic-inorganic hybrid-based, and silsesquioxane-based resins.

  As the polyfunctional acrylate-based and silsesquioxane-based resins used as the curable resin, polyfunctional acrylate monomers, oligomers, urethane acrylate oligomers, alkoxysilanes, alkoxysilane hydrolysates, alkoxysilane oligomers, and the like are preferable. Examples of polyfunctional acrylate monomers include polyfunctional acrylates having two or more (meth) acryloyloxy groups in one molecule and modified polymers thereof. Specific examples include pentaerythritol tri (meth) acrylate and pentaerythritol. Tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate Further, pentaerythritol triacrylate hexanemethylene diisocyanate urethane polymer can be used. These monomers can be used alone or in combination of two or more.

In the present invention, the layer containing the curable resin preferably contains one or more kinds of particles. Here, the particles may be either inorganic particles or organic particles, but it is preferable to contain inorganic particles in order to improve the surface hardness. The inorganic particles are not particularly limited, and examples thereof include metal and metalloid oxides, silicides, nitrides, borides, chlorides, and carbonates. Specifically, silica (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), zinc oxide (ZnO), zirconium oxide (ZrO ₂ ), titanium oxide (TiO ₂ ), antimony oxide (Sb ₂ O ₃ ), and indium At least one particle selected from the group consisting of tin oxide (In ₂ O ₃ ) is preferred. In addition, when particles are introduced for the purpose of improving the surface hardness, the particle diameter is preferably 1 nm or more and 300 nm or less. The particle diameter is more preferably 50 nm or more and 200 nm or less, and still more preferably 100 nm or more and 150 nm or less in terms of achieving both higher levels of surface hardness and bending resistance. The particles are preferably subjected to surface treatment. Surface treatment here refers to introducing a compound onto the particle surface by chemical bonding (including covalent bonding, hydrogen bonding ionic bonding, van der Waals bonding, hydrophobic bonding, etc.) and adsorption (including physical adsorption and chemical adsorption). Say.

  Furthermore, it is preferable that the content rate of curable resin and particle | grains is particle / resin = 20 / 80-80 / 20 by mass ratio. When the particle / resin is less than 20/80, the surface hardness may be insufficient, and when it exceeds 80/20, the bending resistance may be lowered. Since the surface hardness and the bending resistance are compatible at a higher level, the mass ratio of particles / resin is more preferably 30/70 to 70/30, and further preferably 40/60 to 60/40. .

In the laminated sheet for an organic electroluminescence display device of the present invention, the average roughness SRa of the surface of the layer containing the curable resin is preferably 1 to 10 nm. If SRa is less than 1 nm, the slipperiness of the surface is poor and may be scratched. If Ra exceeds 10 nm, the protrusion may be scraped off and scratches may be generated. The average roughness Ra is more preferably 2 to 8 nm, and even more preferably 3 to 7 nm because scratches are more difficult to be scratched. In order to make the average roughness Ra of the hardened layer surface 1 to 10 nm, it can be achieved by adding particles having the above-described particle diameters in the above-described content.
In the present invention, a curable resin is contained on both sides of the film for an organic electroluminescence display device of the present invention in order to suppress the curling of the entire laminated sheet by forming the curable resin layer and further improving the scratch resistance improving effect. A stacked structure including layers is preferable.
The layer containing the curable resin of the present invention preferably has a thickness of 1 μm or more and 20 μm or less. If the thickness of the layer containing the curable resin is less than 1 μm, sufficient surface hardness may not be obtained. Moreover, when the thickness of the layer containing curable resin exceeds 20 micrometers, when a laminated sheet is bent, a crack may generate | occur | produce in the layer containing the laminated | stacked curable resin. The thickness of the layer containing the curable resin is more preferably 2 μm or more and 15 μm or less, and most preferably 3 μm or more and 10 μm or less. In addition, in the case of the structure which has the layer containing curable resin on both surfaces of a film, it is preferable that the thickness of the layer containing curable resin of each surface is 1 micrometer or more and 20 micrometers or less, respectively. Moreover, the layer containing the curable resin of the present invention may be formed of one layer or two or more layers.
The laminate sheet for an organic electroluminescence display device of the present invention has an easy adhesion resin layer having a thickness of 10 nm to 500 nm between the film for an organic electroluminescence display device and a layer containing a curable resin, and the easy adhesion resin. The surface free energy of the layer is preferably 38 mN / m or more. By having a resin layer having a thickness of 10 nm to 500 nm and a surface free energy of 38 mN / m or more, the adhesion between the film and the layer containing the curable resin is improved, and the bending resistance of the laminated sheet is improved. Will improve. The thickness of the easily adhesive resin layer is more preferably 20 nm or more and 400 nm or less, and most preferably 30 nm or more and 300 nm or less. Further, the surface free energy of the easily adhesive resin layer is more preferably 40 mN / m or more, and most preferably 42 mN / m or more.

  Next, the example of the specific manufacturing method of the film for organic electroluminescent display devices of this invention and the laminated sheet for organic electroluminescent display devices is described. Here, polyethylene terephthalate is exemplified as a resin constituting the film, but the present invention is not construed as being limited to such an example.

  First, a polyethylene terephthalate resin is dried and pre-crystallized as a resin used for the film, and then supplied to a single screw extruder and melt extruded. At this time, the resin temperature is preferably controlled to 265 to 295 ° C. Next, foreign matter is removed and the amount of extrusion is leveled through a filter and a gear pump, respectively, and discharged from a T-die onto a cooling drum in a sheet form. At that time, an electrostatic application method in which a cooling drum and the resin are brought into close contact with each other by static electricity using an electrode applied with a high voltage, a casting method in which a water film is provided between the casting drum and the extruded polymer sheet, The sheet-like polymer is brought into close contact with the casting drum, cooled and solidified by a method of sticking the extruded polymer at a glass transition point to (glass transition point−20 ° C.) or a combination of these methods, and unstretched. Get a film. Among these casting methods, when using polyester, a method of applying an electrostatic force is preferably used from the viewpoint of productivity and flatness.

  The unstretched film obtained in the casting step is stretched in the longitudinal direction and then stretched in the width direction, or stretched in the width direction and then stretched in the longitudinal direction, or the longitudinal direction of the film Although it can be obtained by stretching by a simultaneous biaxial stretching method or the like in which the width direction is stretched almost simultaneously, a stretching ratio of 2 to 4 times in each direction is employed. From the viewpoint of unevenness in thickness, the film is preferably stretched 2.5 times or more in each direction. When the plane orientation coefficient is 0.12 to 0.16, the area stretch ratio is 8 times or more and 12 times or less. It is preferable. Further, the stretching temperature is preferably set to such an extent that uneven stretching does not occur. From the viewpoint of setting the thickness direction refractive index to 1.5 or more, for example, a sequential biaxial stretching method of stretching in the width direction after stretching in the longitudinal direction. , The preheating temperature in the longitudinal direction is preferably the glass transition temperature of the resin from −20 ° C. to + 0 ° C., the stretching temperature is preferably from the glass transition temperature of the resin to + 20 ° C., and the preheating temperature in the width direction is the resin. It is preferable that the glass transition temperature is + 20 ° C. or less and the stretching temperature is the glass transition temperature of the resin + 10 ° C. + 60 ° C. Moreover, you may perform extending | stretching in multiple times with respect to each direction.

  Moreover, it is preferable to heat-process the film for organic electroluminescent display devices of this invention after extending | stretching to the width direction. The heat treatment can be performed by any conventionally known method such as in an oven or on a heated roll. The heat treatment is preferably 160 to 240 ° C., and the temperature of the highest heat treatment zone is preferably 220 ° C. or higher and 240 ° C. or lower. Further, the heat treatment can be performed by dividing into a plurality of zones and gradually increasing / decreasing the temperature, or by a method of finely stretching about 1.01 to 1.2 times in the width direction in the heat treatment step. The heat treatment time can be arbitrarily set within a range not deteriorating the characteristics, and is preferably 10 to 60 seconds, more preferably 15 to 30 seconds. Further, the heat treatment may be performed by relaxing the film in the longitudinal direction and / or the width direction.

  In addition, the film for organic electroluminescence display device of the present invention is easy to have a surface free energy of at least 38 mN / m and a surface free energy of at least 38 mN / m from the viewpoint of adhesion to a layer containing a curable resin. It is preferable to laminate an adhesive resin layer. As the method of forming the easy adhesive resin layer, the easy adhesive resin is coated on the film surface (composite melt extrusion method, hot melt coating method, solvent other than water, water-soluble and / or Or an in-line or off-line coating method from a water-dispersible resin), a similar composition or a surface lamination method of a blended product thereof. In particular, an in-line coating method in which orientation crystallization is completed by applying a coating agent on one surface of the film before completion of orientation crystallization, stretching in at least one direction, and heat-treating to complete orientation crystallization. Industrially preferable. Moreover, when providing an easily bonding resin layer by coating, as resin which provides an easily bonding resin layer, it is not specifically limited, For example, acrylic resin, urethane resin, polyester resin, olefin resin, Fluorine resin, vinyl resin, chlorine resin, styrene resin, various graft resins, epoxy resin, silicone resin, and the like can be used, and a mixture of these resins can also be used. From the viewpoint of adhesion, it is preferable to use a polyester resin, an acrylic resin, or a urethane resin. When the polyester resin is used as an aqueous coating liquid, a water-soluble or water-dispersible polyester resin is used. For such water-solubilization or water-dispersion, a compound containing a sulfonate group or a carboxyl group is used. It is preferable to copolymerize a compound containing an acid base. When an acrylic resin is used as an aqueous coating liquid, it needs to be dissolved or dispersed in water, and as an emulsifier, a surfactant (for example, a polyether compound, etc. can be mentioned, but it is not limited. Not.) May be used.

  Moreover, in the easily bonding resin layer used for this invention, in order to improve adhesiveness, various crosslinking agents can be used together with resin. As the crosslinking agent resin, melamine-based, epoxy-based, and oxazoline-based resins are generally used. Examples of the particles contained in the resin layer of the present invention include inorganic particles and organic particles. However, since slipperiness and blocking resistance are improved, inorganic particles are more preferable. As the inorganic particles, silica, alumina, kaolin, talc, mica, calcium carbonate, titanium and the like can be used.

  Next, the manufacturing method of the laminated sheet for organic electroluminescence display devices of the present invention is illustrated.

  As a technique, it is preferable to produce a coating material containing a curable resin on a film substrate in the order of coating, drying and curing. When the layer containing the curable resin is composed of two or more layers, for example, the coating agent C made of the curable resin C and the coating agent D made of the curable resin D are sequentially or simultaneously applied on the film substrate. It is preferable to use a production method obtained in the order of coating, drying and curing. Here, the sequential application means that a first cured layer is formed by applying, drying and curing one type of coating using a dip coating method, a roller coating method, a wire bar coating method, a gravure coating method or a die coating method. After that, the second cured layer is formed by applying, drying and curing a coating agent different from the first type on the first cured layer. About the kind and number of the hardened layers to produce, it can select suitably. The simultaneous application mentioned as the other production method is a method in which two or more kinds of coating agents are simultaneously applied, dried and cured using a multilayer slit die to obtain two or more cured layers by one application. . The drying method herein includes heat transfer drying, drying with hot air, drying by infrared irradiation, and drying by microwave irradiation, and is not particularly limited, but drying by hot air irradiation is preferable.

Examples of the curing method herein include thermal curing by heat and curing by irradiating an active energy ray such as an electron beam or ultraviolet ray. In the case of thermosetting, it is preferable to cure at a temperature of room temperature to 200 ° C., more preferably 80 ° C. to 200 ° C. In the case of curing by irradiating with ultraviolet rays or electron beams, the oxygen concentration is preferably as low as possible, and is preferably cured in an inert gas atmosphere. If the oxygen concentration is high, curing may be insufficient. Examples of the ultraviolet lamp used when irradiating with ultraviolet rays include a discharge lamp method, a flash method, a laser method, and an electrodeless lamp method. When the discharge lamp type to ultraviolet cured using a high pressure mercury lamp is, it is preferable that the illuminance of ultraviolet rays is 100 mW / cm ² or more 3,000 mW / cm ² or less, more preferably 200 mW / cm ² or more 2,000 mW / cm ² or less. More preferably, at 200 mW / cm ² or more 1,500 mW / cm ² or less.

  The film for organic electroluminescence display device and the laminate sheet for organic electroluminescence display device of the present invention are particularly suitable as a cover film for organic electroluminescence display device because of excellent flexibility and flatness after application of a curable resin layer. Can be used. By applying it as a cover film for an organic electroluminescence display device, it is possible to prevent damage to the surface of the display device without impairing the flexibility of the display device.

  The laminated sheet for organic electroluminescence display device of the present invention is a display device having a circularly polarizing plate, and the total thickness of the laminated sheet and the circularly polarizing plate is preferably 120 μm or less. By setting the total thickness of the laminated sheet and the circularly polarizing plate to 120 μm or less, the flexibility of the display device is enhanced, and the display device can be folded and rolled. The total thickness of the laminated sheet and polarizing plate is more preferably 110 μm or less, and most preferably 100 μm or less. Moreover, it is preferable that the organic electroluminescent display apparatus using the laminated sheet for organic electroluminescent display apparatuses of this invention is comprised from the said laminated sheet, a circularly-polarizing plate, and an organic electroluminescent element.

  The circularly polarizing plate in the display device using the laminated sheet for organic electroluminescence display device of the present invention can be applied to an organic electroluminescence display device or the like using an optical film (λ / 4 retardation film). At all wavelengths, the effect of shielding the specular reflection of the metal electrode of the organic electroluminescence element can be exhibited, and reflection during observation can be prevented, and black expression can be improved. In the circularly polarizing plate in the display device using the laminated sheet for organic electroluminescence display device of the present invention, the polarizer is preferably sandwiched between the optical film (λ / 4 retardation film) and the protective film. The polarizer can be obtained by uniaxially stretching a polyvinyl alcohol film and then dyeing or dyeing the polyvinyl alcohol film and then uniaxially stretching, preferably by further performing a durability treatment with a boron compound.

  Although the structure of the organic electroluminescent element of the organic electroluminescent display apparatus using the lamination sheet for organic electroluminescent display apparatuses of this invention is not specifically limited, For example, it has the following layer structure of (i)-(vi). May be. Further, the following light emitting layer is preferably composed of a blue light emitting layer, a green light emitting layer and a red light emitting layer.

Below, the typical example of a structure of an organic EL element is shown.
(I) Anode / hole injection transport layer / light emitting layer / electron injection transport layer / cathode (i) Anode / hole injection transport layer / light emitting layer / electron injection transport layer / cathode (ii) Anode / hole injection transport layer / Light emitting layer / hole blocking layer / electron injection transport layer / cathode (iii) anode / hole injection transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron injection transport layer / cathode (iv) anode / positive Hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (v) anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection Layer / cathode (vi) anode / hole injection layer / hole transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode

  EXAMPLES Hereinafter, although this invention is demonstrated along an Example, this invention is not restrict | limited by these Examples. Various characteristics were measured by the following methods.

(1) Film thickness When measuring the total thickness of a film, the thickness of five arbitrary places of the sample cut out from the film was measured using the dial gauge, and the average value was calculated | required.

(2) Thickness of curable resin layer and easy-adhesive resin layer The thickness of the curable resin layer on the film was measured by observing the cross section using a transmission electron microscope (TEM). The thickness of the curable resin layer was read from an image taken with a TEM at a magnification of 100,000 times. A total of 10 curable resin layers and easy-adhesion resin layer thicknesses were measured, and the average value was used. The observation magnification may be other than 100,000 times as long as the thickness can be measured.

(3) A sample is cut out with a dimension of 100 mm × 100 mm at an arbitrary point on the main orientation axis film, and a film surface is obtained using a microwave molecular orientation meter MOA-2001A (frequency 4 GHz) manufactured by KS Systems (currently Oji Scientific Instruments). The main orientation axis was obtained and defined as the longitudinal direction, and the direction perpendicular to the longitudinal direction was defined as the width direction.
(4) Bending hysteresis 2HB
Using a multi-purpose bending tester (KES-FB2) manufactured by Kato Tech, measurement in the longitudinal direction and width direction was performed under the following conditions to obtain bending hysteresis 2HB. The bending hysteresis 2HB employs data obtained at the fifth cycle (5 repetitions) with a curvature of −2.5 to +2.5 cm ⁻¹ as one cycle.
Number of repetitions: 5 times (5th cycle of recruitment data)
SENS: 2 × 5
Curvature: -2.5 to + 2.5cm ^-1
Deformation speed: 0.50 cm ⁻¹ / sec
Sample size: longitudinal direction × width direction = 20 cm × 20 cm
(5) Bending hardness Using a multi-purpose bending tester (KES-FB2) manufactured by Kato Tech Co., Ltd., the longitudinal and width directions were measured under the following conditions to obtain the bending hardness. In addition, the bending hardness employ | adopted the data obtained by 5th cycle (5 repetitions) by making curvature -2.5- + 2.5cm < ^-1 > into 1 cycle.
Number of repetitions: 5 times (5th cycle of recruitment data)
SENS: 2 × 5
Curvature: -2.5 to + 2.5cm ^-1
Deformation speed: 0.50 cm ⁻¹ / sec
Sample size: longitudinal direction × width direction = 20 cm × 20 cm
(6) Film refractive index and plane orientation coefficient Using sodium D line (wavelength 589 nm) as a light source, using an Abbe refractometer, the refractive index in the longitudinal direction of the film (n _MD ), the refractive index in the width direction (n _TD ), The refractive index (n _ZD ) in the thickness direction was measured, and the plane orientation coefficient (fn) was calculated from the following formula. In the present invention, when the longitudinal direction and the width direction of the film are unknown, the measurement was performed with the main orientation axis direction as the longitudinal direction and the direction orthogonal to the main orientation axis direction as the longitudinal direction.
fn = (n _MD + n _TD ) / 2-n _ZD
(7) The resin composition film constituting the film is dissolved in hexafluoroisopropanol (HFIP), and the content of each monomer residue and by-product diethylene glycol is quantified using ¹ H-NMR and ¹³ C-NMR.
(8) Glass transition temperature of resin
According to JIS K7121 (1987), the differential glass calorimeter DSC-RDC220 manufactured by Seiko Denshi Kogyo Co., Ltd. was used, and “Disk Session” SSC / 5200 was used for data analysis, and the glass transition temperature of the resin was measured. .

(9) 150 ° C. heat shrinkage The film was cut into a rectangular shape having a length of 150 mm and a width of 10 mm in the longitudinal direction and the width direction, respectively. Dotted lines were drawn on the sample at intervals of 100 mm (positions at 50 mm from the center to both ends), and a heat treatment was performed by placing in a hot air oven heated to 150 ° C. with a 3 g weight suspended for 30 minutes. The distance between the marked lines after the heat treatment was measured, and the thermal contraction rate was calculated from the change in the distance between the marked lines before and after heating by the following formula.
Thermal shrinkage (%) = {(distance between marked lines before heat treatment) − (distance between marked lines after heat treatment)} / (distance between marked lines before heat treatment) × 100.

(10) A sample of 20 cm (E direction) x 30 cm (F direction) is prepared at an arbitrary point of the orientation angle variation film in the range of 10 cm × 20 cm, and a microwave molecule manufactured by KS Systems (currently Oji Scientific Instruments) Using the orientation meter MOA-2001A (frequency 4 GHz), the main orientation axis at the center (point G) of the sample was determined and used as the reference direction. Subsequently, the main orientation axes were determined from the four corners of the sample 20 cm (E direction) × 30 cm (F direction) at the positions (4 locations) 5 cm in the E direction and 5 cm in the F direction toward the center of the film, respectively. The angle formed with the direction was defined as the orientation angle of the position. When the measurement positions (four locations) are connected, the size is 10 cm in the E direction and 20 cm in the F direction with the point G as the center, and the largest angle among the orientation angles at the four measurement positions is the film. The orientation angle variation in the 10 cm × 20 cm range was determined.

(11) Preparation of circularly polarizing plate (Circularly polarizing plate-I)
A 40 μm-thick polyvinyl alcohol film was uniaxially stretched (temperature: 110 ° C., stretch ratio: 5 times). This was immersed in an aqueous solution consisting of 0.075 g of iodine, 5 g of potassium iodide, and 100 g of water for 60 seconds. Subsequently, it was immersed in the 68 degreeC aqueous solution which consists of potassium iodide 6g, boric acid 7.5g, and water 100g. This was washed with water and dried to obtain a polarizer. Λ / 4 retardation film (cyclic olefin film 23 μm) pre-corona-treated on one surface of the obtained polarizer, and protective film (triacetyl cellulose film 25 μm) pre-saponified on the other surface Were bonded through an adhesive to produce a circularly polarizing plate having a thickness of 60 μm.

(Circularly polarizing plate-II)
The thickness of the polyvinyl alcohol film is 80 μm, the thickness of the λ / 4 retardation film is 33 μm, the thickness of the protective film is 40 μm, and a circular polarizing plate having a thickness of 95 μm is produced in the same manner as the circular polarizing plate-I. did.

(12) Production of organic electroluminescence display device The film / circular polarizing plate / organic electroluminescence panel of the present invention (15EL9500, manufactured by LG Display) is respectively connected to the organic electroluminescence panel (LG) via an acrylic adhesive (thickness 20 μm). An organic electroluminescence display device was manufactured by bonding to the viewing side of the product name 15EL9500) manufactured by Display.

(13) Static flexibility by mandrel test Longitudinal direction x width direction = 15 mm x 30 mm film was conditioned at 23 ° C and 60% RH for 24 hours, and the center of the base of the mandrel testing machine (manufactured by Ueshima Seisakusho) The film is installed as shown in FIG. A φ1.0 mm test bar is installed, the film is folded at 180 ° C., and left to stand for 24 hours. Thereafter, the film was taken out and immediately placed on a flat floor, and the height lifted from the ground was read. The cut-out direction of the sample is set to the width direction × longitudinal direction = 15 mm × 30 mm, and the raised height is similarly read. Each direction sample was measured 5 times, and the static flexibility was determined from the average height of the lifted 10 times as follows.

Less than 0.2mm: ◎
0.2 mm or more and less than 0.4 mm: ○
0.4 mm or more and less than 0.5 mm: △
0.5 mm or more: ×
(14) Appearance after application of curable resin Apply the curable resin Q described below (preparation of curable resin Q) using a slot die coater while controlling the flow rate so that the thickness after drying is 5 μm. And dried at 100 ° C. for 1 minute to remove the solvent. Next, the film coated with the curable resin was irradiated with 300 mJ / cm ² of ultraviolet rays using a high pressure mercury lamp to obtain a laminated sheet. As the appearance after application of the curable resin layer of the obtained laminated sheet, (a) wrinkles and (b) curls were determined as follows.
(A) There is no wrinkle and the flatness of the whole sheet is good: ◎
Slight film distortion: ○
Clear film distortion is observed, but there is no practical problem: △
The whole film swells and cannot be used: ×
(B) When the curled film was cut out to A4 size and placed on a flat surface, the curled film was determined as follows according to the height of lifting from the ground.
No film lift: ◎
The film lift is less than 10 mm from the ground:
The lift of the film is 10 mm or more and less than 15 mm from the ground: Δ
Film lift exceeds 15mm from the ground: ×
(Manufacture of polyester)
The polyester resin used for film formation was prepared as follows.

(Polyester A)
Polyethylene terephthalate resin (intrinsic viscosity 0.65) in which the terephthalic acid component is 100 mol% as the dicarboxylic acid component and the ethylene glycol component is 100 mol% as the glycol component.

(Polyester B)
Polyester resin (intrinsic viscosity 0.70) in which terephthalic acid component is 100 mol% as dicarboxylic acid component, 1-4 mol in cyclohexanedimethanol component is 12 mol%, and ethylene glycol component is 80 mol% as glycol component
(Polyester C)
Polyester resin with an isophthalic acid component of 15 mol% as a dicarboxylic acid component, an terephthalic acid component of 83 mol%, and an ethylene glycol component as a glycol component of 100 mol% (intrinsic viscosity 0.65)
(Polyphenylene sulfide)
An autoclave (maximum operating pressure: 14 MPa) was charged with 100 moles of sodium sulfide nonahydrate, 45 moles of sodium acetate and 25 liters of N-methyl-2-pyrrolidone (hereinafter abbreviated as NMP) and gradually stirred. The temperature was raised to 220 ° C. and the contained water was removed by distillation. In the system after the dehydration, 100 moles of p-dichlorobenzene as a main component monomer was added together with 5 liters of NMP, and the raw material was pressurized and sealed at 3 Kg / cm ² at a temperature of 170 ° C., then the temperature was raised to 270 ° C. For 4 hours. After completion of the polymerization, the polymer was cooled, the polymer was precipitated in distilled water, and a small polymer was collected by a wire mesh containing a 150 mesh opening. The small polymer obtained in this way was washed twice with distilled water at 90 ° C., then washed three times with an aqueous sodium acetate solution, then washed once with distilled water, and dried at a temperature of 120 ° C. under reduced pressure. As a result, granules of polyarylene sulfide resin having a melting point of 280 ° C. were obtained. The granules were put into a bi-directional rotary twin-screw kneading extruder with a vent heated to 320 ° C. (manufactured by Nippon Steel Works, screw diameter 30 mm, screw length / screw diameter = 45.5), and the residence time was 90 seconds. The melt was extruded at a screw speed of 150 revolutions / minute, discharged into a strand, cooled with water at a temperature of 25 ° C., and immediately cut to produce a chip, thereby obtaining polyphenylene sulfide.

(Polypropylene A)
Prime Polymer Co., Ltd. TF850H, MFR: 2.9 g / 10 min was used as polypropylene A.

(Particle Master A)
Polyethylene terephthalate particle master (intrinsic viscosity 0.65) containing polyester carbonate A with calcium carbonate particles having an average particle diameter of 1.2 μm at a particle concentration of 1 mass%.

(Preparation of easy adhesion resin P)
The easy adhesion resin layer laminated | stacked on the surface of a film was prepared as follows.

Resin solution (a): terephthalic acid (88 mol%) as an acid component, 5-sodium sulfoisophthalic acid (12 mol%), ethylene glycol (100 mol%) as a diol component
70 parts by weight of a water-soluble polyester resin water-soluble coating solution composed of an acid component and a diol component, and terephthalic acid (50 mol%), isophthalic acid (49 mol%) and 5-sodium sulfoisophthalic acid (1 mol%) as acid components And 30 parts by weight of an aqueous dispersion of a polyester resin composed of an acidic component of ethylene glycol (55 mol%), neopentyl glycol (44 mol%), polyethylene glycol (molecular weight: 4000) (1 mol%) and a diol component. Solution.
Crosslinking agent (b): methylol group type melamine crosslinking agent crosslinking agent (c): oxazoline group-containing crosslinking agent particle (d): aqueous dispersion of colloidal silica particles having a particle size of 150 nm (e): colloidal having a particle size of 300 nm Rusilica particle water dispersion Fluorosurfactant (f): Megafac F-444 manufactured by DIC Corporation
These are (a) / (b) / (c) / (d) / (e) / (f) = 47 parts by weight / 19 parts by weight / 20 parts by weight / 4.9 parts by weight / 0. Mixed at 7 parts by weight / 0.1 part by weight.
The refractive index is 1.57.

(Formulation of curable resin Q)
Silica particles having a particle size of 100 nm (organosilica sol manufactured by Nissan Chemical Industries, Ltd.) and polyfunctional acrylate (KAYARAD PET30 manufactured by Nippon Kayaku Co., Ltd.) are mixed at a mass ratio of 50:50, and a toluene / MEK mixed solvent (mass ratio). 50:50) and diluted to prepare a curable resin.

(Examples 1-5, 7-11, Comparative Examples 1, 2, 4, 5)
As shown in Table 1, the resin species and particle master species were mixed at the contents shown in Table 1 and charged into the extruder, and then melted at the extruder temperature shown in Table 2. The sheet was discharged on a cooling drum controlled to the temperature described in 1. At that time, a wire electrode having a diameter of 0.1 mm was applied electrostatically and adhered to the cooling drum to obtain an unstretched sheet. Thereafter, the film was rapidly cooled with a cooling roll whose temperature was controlled at 10 ° C., subsequently, stretched in the longitudinal direction at the stretching temperature and stretch ratio shown in Table 2, and then cooled once. Next, corona discharge treatment is applied to both sides of the uniaxially stretched film, the wetting tension of the film is 55 mN / m, and the easy-adhesive resin P is applied to both sides of the film. The film was stretched in the width direction at a magnification, relaxed in the heat treatment at the heat treatment temperature described in Table 2 and in the width direction in the tenter, and a film having a film thickness described in Table 2 was obtained. The physical properties of the obtained film are as shown in Table 3, and since the bending hysteresis was 0.01 gf · cm ² / cm or more and 0.04 gf · cm ² / cm or less for the examples, Excellent appearance after application of curable resin.
Moreover, the curable resin Q was applied to both surfaces of the films obtained in Examples 1 to 5 so as to have a thickness of 5 μm, and dried at 100 ° C. for 1 minute to remove the solvent. Next, the film coated with the curable resin layer was irradiated with 300 mJ / cm ² of ultraviolet rays using a high-pressure mercury lamp, Example 7 was Example 1, Example 8 was Example 2, Example 9 was Example 3, Example 10 obtained the laminated sheet for organic electroluminescent display devices using the film of Example 4 and Example 11 of Example 5. As shown in Table 4 for the laminated sheets of Examples 8 to 12, since a film having a bending hysteresis of 0.01 gf · cm ² / cm or more and 0.04 gf · cm ² / cm or less was used, static flexibility and The appearance was excellent.
On the other hand, in Comparative Examples 1, 2, 4, and 5, since the bending hysteresis exceeded 0.04 gf · cm ² / cm, the static flexibility was inferior.
(Examples 6 and 12)
Polyphenylene sulfide A was dried under reduced pressure at 180 ° C. for 3 hours and then supplied to a full flight single screw extruder whose melting part was heated to 320 ° C. at a discharge rate of 50 kg / hr. After filtration through a 16 μm cut filter heated to 300 ° C., melt-extruded from a T-die (die) set at a temperature of 320 ° C., and then solidified by cooling and solidifying while applying an electrostatic charge to a cast drum having a surface temperature of 25 ° C. A 400 μm unstretched film was obtained. Next, after the obtained unstretched film is preheated with a plurality of heating rolls heated to a surface temperature of 90 ° C., the heating roll heated to a surface temperature of 100 ° C. differs from the convergence provided next to the heating roll. The film was stretched 3.7 times in the longitudinal direction (MD direction) with a 30 ° C. cooling roll. The uniaxially stretched sheet thus obtained was stretched 3.7 times at a temperature of 95 ° C. in a direction perpendicular to the longitudinal direction (TD direction) using a tenter, subsequently heat treated at 260 ° C., and subsequently 260 After a relaxation treatment of 5% in the TD direction at 0 ° C., the film was cooled to room temperature to obtain a film having a thickness of 25 μm. The physical properties of the obtained film are as shown in Table 3, and since the bending hysteresis was 0.01 gf · cm ² / cm or more and 0.04 gf · cm ² / cm or less, static flexibility and curable resin application The appearance afterwards was excellent.
Moreover, the curable resin Q was applied to both surfaces of the obtained film so as to have a thickness of 5 μm, and a laminated sheet shown in Table 2 was obtained. As shown in Table 4, since the bending hysteresis of the laminated sheet was 0.02 gf · cm ² / cm or more and 0.08 gf · cm ² / cm or less, it was excellent in static flexibility and appearance.
(Comparative Example 3)
Polypropylene A is supplied to a single-screw melt extruder, melt extruded at 240 ° C., foreign matter is removed by a 60 μm cut sintered filter, the melt sheet is discharged onto a cast drum whose surface is controlled at 80 ° C., and air It was brought into close contact with a knife and cooled and solidified to obtain an unstretched sheet. Subsequently, it preheated to 125 degreeC using the some ceramic roll, and 4.6 time extending | stretching was performed at 125 degreeC in the longitudinal direction of the film. Next, the end portion was introduced into a tenter type stretching machine by gripping, preheated at 170 ° C. for 3 seconds, and then stretched 8.0 times at 165 ° C. In the subsequent heat treatment process, heat treatment is performed at 165 ° C. while giving a relaxation of 10% in the width direction, and after that, through a cooling process at 130 degrees, the film is led to the outside of the tenter, the film end clip is released, and a film with a thickness of 25 μm is formed. Obtained. The physical properties of the obtained film are as shown in Table 3, and since the bending hysteresis was less than 0.01 gf · cm ² / cm, it was excellent in static flexibility, but in the appearance after application of the curable resin. It was inferior.

  The film for an organic electroluminescence display device and the laminated sheet for an organic electroluminescence display device of the present invention are particularly suitable as a cover film for an organic electroluminescence display device because the bending hysteresis 2HB indicating the recovery property during bending deformation is in a specific range. Can be used.

Claims (8)

A film for an organic electroluminescence display device, wherein bending hysteresis 2HB obtained from a bending test in a longitudinal direction and a width direction is both 0.01 gf · cm / cm and 0.04 gf · cm / cm. The b value obtained from a spectral color difference meter is 2.0 or less, and the total light transmittance is 90% or more, The film for organic electroluminescent display devices of Claim 1 characterized by the above-mentioned. The organic electroluminescence display device film according to claim 1 or 2 bending stiffness in the longitudinal direction and the width direction are both 0.01gf · ^cm 2 · ^cm or more 0.1 gf · ^cm 2 · cm or less. The polyester film for an organic electroluminescence display device according to any one of claims 1 to 3, wherein variation in orientation angle in a range of 10 cm in the longitudinal direction and 20 cm in the width direction of the film is within 5 °. The at least 150 ° C. heat shrinkage in the width direction is 1% or less, and the 150 ° C. heat shrinkage in the longitudinal direction is in the range of −2% or more and 2% or less with respect to the 150 ° C. heat shrinkage in the width direction. The film for organic electroluminescent display apparatuses in any one of 1-4. The film for organic electroluminescent display devices according to any one of claims 1 to 5, comprising polyester as a main constituent. The polyester film for organic electroluminescence display devices according to any one of claims 1 to 6, wherein the refractive index in the thickness direction is 1.5 or more. The laminated sheet for organic electroluminescent display apparatuses which has a layer containing curable resin in the at least single side | surface of the film for organic electroluminescent display apparatuses in any one of Claims 1-7.