Multilayer structure, method for manufacturing same, and protective sheet for electronic device obtained using same, and electronic device

Abstract

Provided are: a multilayer structure having high barrier properties and clarity; a method for manufacturing the multilayer structure; a protective sheet for an electronic device obtained using the multilayer structure; and an electronic device. A multilayer structure provided with a base material (X) and a layer (Y), in which the layer (Y) contains a reaction product (D) of a metal oxide (A) containing aluminum atoms and an inorganic phosphorus compound (BI), at least one group of the base material (X) is adjacent to the layer (Y), and the a * value and the b * value of the L * a * b * color system as measured in accordance with JIS Z 8722: 2009 are-0.8 to 0.8 and-0.8 to 0.8.

Description

Technical Field

[0001] The present invention relates to a multilayer structure having high gas barrier properties, water vapor barrier properties and high clarity, a method for producing the same, and a protective sheet for an electronic device and the electronic device obtained using the same. Background Art

[0002] Electronic devices such as those equipped with solar cells and display devices require a light-transmitting protective member to protect their surfaces. Examples of such protective members include protective sheets with excellent barrier properties (oxygen barrier properties and water vapor barrier properties) formed by a barrier layer on a thick glass plate or resin substrate.

[0003] As a protective sheet having excellent barrier properties, Patent Document 1 describes, for example, an electronic device having a protective sheet comprising a multilayer structure, wherein a coating liquid containing an aluminum compound and a phosphorus compound is applied to a substrate (X), followed by drying and heat treatment to provide a layer (Y) containing a reaction product, wherein the average particle size of the reaction product is 5 to 70 nm. Patent Document 1 describes that the protective sheet has excellent gas barrier properties and water vapor barrier properties and can maintain its performance even after a heat test.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2016 / 103720 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] In recent years, there has been a growing demand for higher levels of clarity in protective sheets (multilayer structures) for electronic devices and the like. However, the multilayer structures used in conventional electronic devices have sometimes exhibited insufficient clarity. The high barrier properties of the multilayer structures used in conventional electronic devices are useful as protective sheets for electronic devices and the like, and there is a need for multilayer structures that maintain this performance while also exhibiting high clarity.

[0009] The present invention has been made based on the above circumstances, and an object of the present invention is to provide a multilayer structure having high barrier properties and clarity, a method for producing the same, and a protective sheet for an electronic device and the electronic device obtained using the same.

[0010] Means used to solve problems

[0011] The present inventors have conducted several studies to realize a multilayer structure with high definition, using a substrate with high image definition as the substrate (X), but it is difficult to realize high definition. As a result of intensive research, the present inventors have found that: ＊ a ＊ b＊ a* value and b value of the color system ＊ The value is related to the clarity of the multilayer structure. ＊ Value and b ＊ The value is correlated with the time from the completion of coating of the coating liquid to the start of drying when forming the layer (Y), thereby completing the present invention.

[0012] That is, the present invention is achieved by providing the following aspects.

[0013] [1] A multilayer structure comprising a substrate (X) and a layer (Y), wherein the layer (Y) comprises a reaction product (D) of a metal oxide (A) containing aluminum atoms and an inorganic phosphorus compound (BI), wherein at least one substrate (X) and the layer (Y) are adjacent to each other, and wherein the a* value of the L*a*b* color system measured in accordance with JIS Z 8722: 2009 is not less than -0.8 and not more than 0.8, and the b ＊ The value is above -0.8 and below 0.8;

[0014] [2] The multilayer structure of [1], which satisfies the following condition 1;

[0015] (Condition 1)

[0016] In a brightness analysis in which reflected light observed when a multilayer structure is moved in the MD direction at a constant speed while being irradiated with light from a white light source is intermittently measured using a line sensor camera, the white light source is irradiated from one side of the multilayer structure at an angle of 25° relative to the perpendicular direction of the multilayer structure, and the line sensor camera measures the reflected light from the same side as the white light source and at an angle of -30° relative to the perpendicular direction of the multilayer structure. The resulting brightness is baseline corrected by fitting the brightness values within a range of 12 mm in width (TD direction) at the center point in the MD direction of the measurement range using the least squares method, and the minimum value of the standard deviation of the brightness values calculated from the baseline-corrected values is less than 1.2.

[0017] [3] The multilayer structure of [1] or [2], wherein the surface roughness of layer (Y) measured by white light interferometry is 70 nm or less;

[0018] [4] The multilayer structure according to any one of [1] to [3], wherein the water vapor transmission rate at 40°C and 90% RH measured in accordance with ISO 15106-3:2003 is 1×10 -2 g / m 2 ·Days or less;

[0019] [5] The multilayer structure according to any one of [1] to [4], wherein the substrate (X) has a surface layer;

[0020] [6] The multilayer structure according to any one of [1] to [5], which has a structure in which at least one set of the substrate (X) and the layer (Y) are directly laminated;

[0021] [7] The multilayer structure according to any one of [1] to [6], which has a structure in which at least one set of a substrate (X) and a layer (Y) are laminated via an adhesive layer (I);

[0022] [8] The multilayer structure according to any one of [1] to [7], wherein the layers (Y) are disposed on both sides of the substrate (X);

[0023] [9] The multilayer structure according to any one of [1] to [8], wherein the infrared absorption spectrum of layer (Y) is 800 to 1400 cm -1 The maximum absorption wave number in the region is between 1080 and 1130 cm -1 scope;

[0024]

[10] The multilayer structure according to any one of [1] to [9], wherein the image clarity of the substrate (X) at a comb width of 0.25 mm measured in accordance with ISO 17221 is 85% or more;

[0025]

[11] The multilayer structure according to any one of [1] to

[10] , wherein a ＊ Value and b ＊ The difference in values (a ＊ value-b ＊ value) is greater than -1.0 and less than 1.0;

[0026]

[12] A method for producing a multilayer structure, comprising: a step (I) of coating a coating liquid (S) comprising a metal oxide (A) containing aluminum atoms, an inorganic phosphorus compound (BI), and a solvent on at least one side of a substrate (X), and heating and drying the coating liquid at a temperature of 120° C. or higher to remove the solvent, thereby forming a precursor layer of a layer (Y); and a step (II) of forming a layer (Y) by heat-treating the precursor layer of the layer (Y).

[0027] In step (I), the time from the completion of coating of the coating liquid (S) to the start of heat drying is 1.8 seconds to 9.0 seconds, and the L of the obtained multilayer structure measured in accordance with JIS Z 8722: 2009 is ＊ a ＊ b ＊ The a* value of the color system is -0.8 or more and 0.8 or less, and b ＊ The value is above -0.8 and below 0.8;

[0028]

[13] The method for producing a multilayer structure of

[12] , wherein the coating liquid (S) satisfies the following condition 2;

[0029] (Condition 2)

[0030] For the use of corona treatment equipment at 130W·min / m 2 A 2.0 μL drop of the coating liquid (S) was added to the treated surface of the polyethylene terephthalate film at 23° C. and 50% RH, and the contact angle of the drop after 2 seconds was 20° or more and 35° or less.

[0031]

[14] The method for producing a multilayer structure of

[13] , wherein the coating liquid (S) contains a water / methanol mixed solvent as a solvent, and the water / methanol ratio of the mixed solvent is 3.5 / 6.5 or more and 7 / 3 or less;

[0032]

[15] The method for producing a multilayer structure according to any one of

[12] to

[14] , wherein the viscosity of the coating liquid (S) is 400 mPa·s or more and 5000 mPa·s or less, and the surface roughness of the layer (Y) measured by white light interferometry is 70 nm or less;

[0033]

[16] A protective sheet for an electronic device, comprising the multilayer structure according to any one of [1] to

[11] ;

[0034]

[17] The protective sheet of

[16] , which is a protective sheet for protecting the surface of a photoelectric conversion device, an information display device, or a lighting device;

[0035]

[18] An electronic device having the protective sheet of

[16] or

[17] .

[0036] Effects of the Invention

[0037] According to the present invention, a multilayer structure having high barrier properties and clarity, a method for producing the same, and a protective sheet for an electronic device and the electronic device obtained using the same can be provided. DETAILED DESCRIPTION

[0038] In this specification, "barrier properties" primarily refer to both oxygen barrier properties and water vapor barrier properties, and "gas barrier properties" primarily refer to oxygen barrier properties. Furthermore, "clarity" is an evaluation of the clarity of an image viewed through the multilayered structure of the present invention. As described in the Examples, this is determined based on the visibility of the image viewed through the multilayered structure of the present invention.

[0039] The multilayer structure of the present invention is a multilayer structure comprising a substrate (X) and a layer (Y), wherein the layer (Y) comprises a reaction product (D) of a metal oxide (A) and an inorganic phosphorus compound (BI), at least one pair of substrates (X) and layer (Y) are adjacent to each other, and L measured according to JIS Z8722:2009 is ＊ a ＊ b＊ The a* value of the color system is -0.8 or more and 0.8 or less, and b ＊ The value is greater than -0.8 and less than 0.8. Here, in this specification, "adjacent" means directly stacked or stacked via other layers such as adhesive layers. In addition, "at least one group of substrates (X) and layers (Y)" are adjacent, which means that, for example, when there are multiple substrates (X), the substrate (X) and layer (Y) of one layer are adjacent, and the other substrates (X) and layers (Y) may be adjacent or not. Similarly, when there are multiple layers (Y), the layer (Y) and substrate (X) of one layer are adjacent, and the other layers (Y) and substrate (X) may be adjacent or not. It is preferred that all substrates (X) and layers (Y) are adjacent. In addition, it is preferred that all layers (Y) and substrate (X) are adjacent. The L of the multilayer structure of the present invention measured in accordance with JIS Z 8722:2009 ＊ a ＊ b ＊ The a* value of the color system is -0.8 or more and 0.8 or less, and b ＊ The value is -0.8 or more and 0.8 or less, and thus, when used as a protective sheet for electronic devices, for example, the clarity is excellent. ＊ Value and b ＊ The method of achieving the above-mentioned range is described in detail below. It is particularly important that the image clarity of the substrate (X) is high and the time from the completion of application of the coating liquid (S) to the start of heating and drying is within the range of 1.8 seconds to 9.0 seconds.

[0040] [Base material (X)]

[0041] The substrate (X) is not particularly limited, but preferably comprises a thermoplastic resin from the viewpoint of achieving high image clarity. The form of the substrate (X) is not particularly limited, but is preferably a layered form such as a film or sheet. The substrate (X) preferably comprises a thermoplastic resin film or a thermoplastic resin film laminated with an inorganic vapor-deposited layer (X'), more preferably comprises a thermoplastic resin film, and even more preferably is a thermoplastic resin film.

[0042] Examples of the thermoplastic resin used in the substrate (X) include polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate (PET), polyethylene 2,6-naphthalate, polybutylene terephthalate, or copolymers thereof; polyamide resins such as nylon-6, nylon-66, and nylon-12; hydroxyl-containing polymers such as polyvinyl alcohol and ethylene-vinyl alcohol copolymers; polystyrene; poly(meth)acrylate; polyacrylonitrile; polyvinyl acetate; polycarbonate; polyarylate; regenerated cellulose; polyimide; polyetherimide; polysulfone; polyethersulfone; polyetheretherketone; ionomer resins, etc. The thermoplastic resin used in the substrate (X) is preferably at least one selected from polyethylene, polypropylene, polyethylene terephthalate, nylon-6, and nylon-66. Polyethylene terephthalate is more preferred from the viewpoint of excellent image clarity.

[0043] In order to impart slipperiness and adhesion resistance, substrate (X) may include inorganic particles or organic particles. From the viewpoint of the image clarity of substrate (X), when including inorganic particles and organic particles, it is preferably included in the surface layer described later. That is, from the viewpoint of image clarity, it is sometimes preferred that inorganic particles or organic particles are not included in the part other than the surface layer of substrate (X). As inorganic particles, metals such as gold, silver, copper, platinum, palladium, rhenium, vanadium, osmium, cobalt, iron, zinc, ruthenium, praseodymium, chromium, nickel, aluminum, tin, zinc, titanium, tantalum, zirconium, antimony, indium, yttrium, and lanthanum can be used; metal oxides such as zinc oxide, titanium oxide, cesium oxide, antimony oxide, tin oxide, indium tin oxide, yttrium oxide, lanthanum oxide, zirconium oxide, aluminum oxide, and silicon oxide; metal fluorides such as lithium fluoride, magnesium fluoride, aluminum fluoride, and cryolite; metal phosphates such as calcium phosphate; carbonates such as calcium carbonate; sulfates such as barium sulfate; other talc and kaolin, etc. As organic fine particles, in addition to crosslinked fine particles such as silicone compounds, crosslinked styrene, crosslinked acrylic, and crosslinked melamine, thermoplastic resins that are incompatible with the thermoplastic resin constituting the substrate layer (X) but are finely dispersed to form a sea-island structure can also be used. The average particle size of the fine particles used is preferably 0.001 to 5 μm.

[0044] When the aforementioned thermoplastic resin film is used as the substrate (X), the substrate (X) may be a stretched film or an unstretched film. From the perspective of excellent processing adaptability (printing, lamination, etc.) of the resulting multilayer structure, a stretched film is preferred, and a biaxially stretched film is particularly preferred. The biaxially stretched film may be a biaxially stretched film produced by any of the simultaneous biaxial stretching method, the sequential biaxial stretching method, and the tubular stretching method.

[0045] The thickness of each layer of the substrate (X) is preferably 5 μm or more and 200 μm or less, more preferably 7 μm or more and 150 μm or less, and even more preferably 10 μm or more and 100 μm or less. When the thickness of each layer of the substrate (X) is 5 μm or more, excellent mechanical strength and processability tend to be exhibited. In addition, when the thickness of each layer of the substrate (X) is 200 μm or less, the resulting multilayer structure tends to have excellent flexibility.

[0046] The substrate (X) preferably has high image clarity. The image clarity of the substrate (X) is preferably 85% or more, more preferably 90% or more, and further preferably 92% or more. From the viewpoint of manufacturing cost, the image clarity of the substrate (X) may be 99% or less, 97% or less, 96% or less, or 95% or less. If the image clarity of the substrate (X) is 85% or more, the a of the obtained multilayer structure ＊ Value and b ＊ The value can be easily adjusted to be between -0.8 and 0.8. Furthermore, if the image clarity of the substrate (X) is 85% or higher, the standard deviation of the brightness values of the multilayer structure described later can be easily adjusted to a low value, and the surface irregularities of the layer (Y) can also be easily adjusted to a small value. The image clarity of the substrate (X) is the average value of five measurements performed in accordance with ISO 17221 with a comb width of 0.25 mm.

[0047] Examples of means for adjusting the image clarity of the substrate (X) to 85% or higher include: not containing additives (such as inorganic fine particles and organic fine particles) in layers other than the surface layer described below, or containing them in small amounts; and providing the surface layer described below.

[0048] In order to impart various functions and from the viewpoint of improving the image clarity of substrate (X), substrate (X) preferably has a surface layer. The surface layer is a layer arranged on the surface of substrate (X), and can be arranged on a single side of substrate (X) or on both sides. As long as the surface layer has adhesiveness relative to the material used in substrate (X), it is not particularly limited, preferably with a thermoplastic resin as the main component. Herein, "with ... as the main component" refers to more than 50% by mass. As the aforementioned thermoplastic resin, polyester resin, polycarbonate resin, epoxy resin, alkyd resin, acrylic resin, urea resin, carbamate resin, etc. can be suitably used. In addition, different two or more thermoplastic resins, such as polyester resin and carbamate resin, polyester resin and acrylic resin, or carbamate resin and acrylic resin, etc. can be used in combination. Among them, preferably at least one selected from polyester resin, acrylic resin and carbamate resin, more preferably polyester resin.

[0049] From the perspective of significantly improving both heat-resistant adhesion and moisture-resistant adhesion, it is sometimes preferable for the surface layer to contain various crosslinking agents. In particular, when a polyester resin, urethane resin, or acrylic resin is used as the main component of the surface layer, and these resins are copolymerized with crosslinkable functional groups, it is preferable to further contain a crosslinking agent. The thermoplastic resin and crosslinking agent that constitute the surface layer can be mixed in any ratio. From the perspective of improving adhesion, the crosslinking agent is preferably present in an amount of 0.2 to 20 parts by mass, more preferably 0.5 to 15 parts by mass, and even more preferably 1 to 10 parts by mass per 100 parts by mass of the resin.

[0050] The surface layer may contain the aforementioned inorganic fine particles or organic fine particles in order to impart lubricity and anti-blocking properties.

[0051] Commercially available products can be used as the substrate (X). Examples of commercially available products with high image clarity include Lumira (registered trademark) U403, U483, A48, and XW731C manufactured by Toray Industries, Inc.; RH210 manufactured by Hyosung Corporation; Daihoil (registered trademark) T600 manufactured by Mitsubishi Chemical Corporation; Cosmoshine (registered trademark) A4160 and SRF manufactured by Toyobo Co., Ltd.; and Toyobo Esther (registered trademark) HPE film. These products have a surface layer on both sides or one side.

[0052] From the perspective of the coating properties of the coating liquid (S) described below and the barrier properties of the resulting multilayer structure, the substrate (X) is preferably surface-treated. Surface treatment can be performed by a known method, and examples thereof include UV ozone treatment, high-concentration ozone water treatment, excimer ozone treatment, corona treatment, oxygen plasma treatment, and AP plasma treatment.

[0053] The thermoplastic resin film laminated with an inorganic vapor-deposited layer (X') used as a substrate (X) is generally a film having barrier properties for oxygen and water vapor, and is a transparent film. When a thermoplastic resin film laminated with an inorganic vapor-deposited layer (X') is used as a substrate (X), the layer (Y) described later is usually laminated on the inorganic vapor-deposited layer (X') side. As the thermoplastic resin film used in the thermoplastic resin film laminated with an inorganic vapor-deposited layer (X'), the thermoplastic resin film exemplified as the above-mentioned substrate (X) can be used. The inorganic vapor-deposited layer (X') can be formed by vapor-depositing an inorganic substance. As an inorganic substance, metal oxides (such as silicon oxide, aluminum oxide), metal nitrides (such as silicon nitride) or metal nitrogen oxides (such as silicon oxynitride) etc. can be listed. Among them, from the viewpoint of excellent transparency, the inorganic vapor-deposited layer (X') formed of aluminum oxide, silicon oxide, magnesium oxide or silicon nitride is preferred. In addition, from the viewpoint of image clarity, it is sometimes preferable not to include the inorganic vapor-deposited layer (X').

[0054] The method for forming the inorganic vapor deposition layer (X') is not particularly limited, and examples thereof include physical vapor growth methods such as vacuum evaporation (for example, resistance heating evaporation, electron beam evaporation, molecular beam epitaxy, etc.), sputtering, and ion plating; chemical vapor growth methods such as thermal chemical vapor growth (for example, catalytic chemical vapor growth), photochemical vapor growth, plasma chemical vapor growth (for example, capacitively coupled plasma, inductively coupled plasma, surface wave plasma, electron cyclotron resonance, dual magnetron, atomic layer deposition, etc.), and organometallic vapor growth.

[0055] The thickness of the inorganic vapor-deposited layer (X') varies depending on the type of components constituting the inorganic vapor-deposited layer, and is preferably 0.002 to 0.5 μm, more preferably 0.005 to 0.2 μm, and even more preferably 0.01 to 0.1 μm. Within this range, a thickness that allows the barrier properties and mechanical properties of the multilayer structure to be good can be selected. If the thickness of the inorganic vapor-deposited layer (X') is 0.002 μm or more, the barrier properties of the inorganic vapor-deposited layer (X') to oxygen and water vapor tend to be good. In addition, if the thickness of the inorganic vapor-deposited layer (X') is 0.5 μm or less, the inorganic vapor-deposited layer (X') tends to fully maintain its barrier properties after bending.

[0056] As the substrate (X), one type of substrate may be used alone, or two or more types of substrates may be used in combination. When a plurality of substrates (X) are present, each substrate (X) may be the same or different.

[0057] [Layer(Y)]

[0058] Layer (Y) comprises a reaction product (D) of a metal oxide (A) and an inorganic phosphorus compound (BI). In the multilayer structure of the present invention, layer (Y) functions as a barrier layer. Therefore, by including layer (Y) in the multilayer structure of the present invention, the barrier properties tend to be improved. In addition, by forming layer (Y) using an appropriate method, the L value measured in accordance with JIS Z8722:2009 can be increased. ＊ a ＊ b ＊ The a* value of the color system is -0.8 or more and 0.8 or less, and b ＊ The value is -0.8 or more and 0.8 or less. In addition, by forming the layer (Y) and the like by an appropriate method, the multilayer structure can satisfy the condition 1 described in detail later.

[0059] (Metal oxide containing aluminum atoms (A))

[0060] The metal atoms constituting the metal oxide (A) (these are sometimes collectively referred to as "metal atoms (M)") are at least one metal atom selected from metal atoms belonging to Groups 2 to 14 of the periodic table, and include at least an aluminum atom. The metal atom (M) is preferably an aluminum atom alone, but may include aluminum atoms and metal atoms other than these. It should be noted that as the metal oxide (A), two or more metal oxides (A) may be used in combination. Examples of metal atoms other than aluminum atoms include metals of Group 2 of the periodic table such as magnesium and calcium; metals of Group 12 of the periodic table such as zinc; metals of Group 13 of the periodic table; metals of Group 14 of the periodic table such as silicon; and transition metals such as titanium and zirconium. It should be noted that silicon is sometimes classified as a semimetal, but in this specification, silicon is included in the metals. As the metal atom (M) that can be used in combination with aluminum, from the viewpoint of handleability and excellent gas barrier properties of the obtained multilayer structure, it is preferably at least one selected from titanium and zirconium.

[0061] The proportion of aluminum atoms in the metal atoms (M) is preferably 50 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and may be 95 mol% or more, or may be composed essentially only of aluminum atoms. Examples of the metal oxide (A) include metal oxides produced by methods such as liquid phase synthesis, vapor phase synthesis, and solid pulverization.

[0062] The metal oxide (A) may be a hydrolysis condensate of a compound (E) (hereinafter sometimes abbreviated as "compound (E)") containing a metal atom (M) bonded to a characteristic group capable of hydrolysis. Examples of the characteristic group include a halogen atom, NO3, an alkoxy group having 1 to 9 carbon atoms which may be substituted, an aryloxy group having 6 to 9 carbon atoms which may be substituted, an acyloxy group having 2 to 9 carbon atoms which may be substituted, an alkenyloxy group having 3 to 9 carbon atoms which may be substituted, a β-diketone group having 5 to 15 carbon atoms which may be substituted, or a diacylmethyl group having an acyl group having 1 to 9 carbon atoms which may be substituted. The hydrolysis condensate of the compound (E) can be substantially regarded as the metal oxide (A). Therefore, in this specification, the hydrolysis condensate of the compound (E) may sometimes be referred to as "metal oxide (A)". That is, in this specification, the "metal oxide (A)" may be regarded as the "hydrolysis condensate of the compound (E)", and the "hydrolysis condensate of the compound (E)" may be regarded as the "metal oxide (A)".

[0063] (Compound (E) containing a metal atom (M) bonded to a hydrolyzable characteristic group)

[0064] The compound (E) preferably includes the aluminum atom-containing compound (Ea) described later, from the viewpoint of easy control of the reaction with the inorganic phosphorus compound (BI) and excellent gas barrier properties of the obtained multilayer structure.

[0065] Examples of the compound (Ea) include aluminum chloride, aluminum nitrate, aluminum acetate, tris(2,4-pentanedione)aluminum, aluminum trimethoxide, aluminum triethoxide, aluminum tri-n-propoxide, aluminum triisopropoxide, aluminum tri-n-butoxide, aluminum tri-sec-butoxide, and aluminum tri-tert-butoxide. Among these, aluminum triisopropoxide and aluminum tri-sec-butoxide are preferred. Two or more compounds (Ea) may be used in combination.

[0066] Furthermore, the compound (E) may include a compound (Eb) containing a metal atom (M) other than aluminum. Examples of the compound (Eb) include titanium compounds such as tetrakis(2,4-pentanedionato)titanium, titanium tetramethoxide, titanium tetraethoxide, titanium tetraisopropoxide, titanium tetra-n-butoxide, and titanium tetrakis(2-ethylhexoxide); and zirconium compounds such as tetrakis(2,4-pentanedionato)zirconium, zirconium tetra-n-propoxide, and zirconium tetra-n-butoxide. These compounds (Eb) may be used alone or in combination of two or more.

[0067] The proportion of compound (Ea) in compound (E) is not particularly limited, but is, for example, preferably 80 mol% or more, more preferably 90 mol% or more, further preferably 95 mol% or more, and may be 100 mol%.

[0068] By hydrolyzing the compound (E), at least a portion of the characteristic groups capable of hydrolysis of the compound (E) is converted into hydroxyl groups. Furthermore, by condensing its hydrolyzate, the metal atom (M) is bonded via an oxygen atom (O) to form a compound. If this condensation is repeated, a compound that can be regarded as a metal oxide is formed. It should be noted that hydroxyl groups are usually present on the surface of the metal oxide (A) formed by such operation.

[0069] In this specification, compounds having a ratio of [the number of moles of oxygen atoms (O) bonded only to metal atoms (M)] / [the number of moles of metal atoms (M)] of 0.8 or more are included in the metal oxide (A). Here, the oxygen atom (O) bonded only to the metal atom (M) is the oxygen atom (O) in the structure represented by MOM, and does not include oxygen atoms bonded to the metal atom (M) and hydrogen atoms (H) as in the structure represented by MOH. The aforementioned ratio of the metal oxide (A) is preferably 0.9 or more, more preferably 1.0 or more, and further preferably 1.1 or more. The upper limit of the ratio is not particularly limited. If the atomic valence of the metal atom (M) is denoted as n, it is generally represented by n / 2.

[0070] In order for the hydrolysis and condensation to occur, it is important that the compound (E) has characteristic groups capable of hydrolysis. If these groups are not bonded, the hydrolysis and condensation reaction will not occur or will proceed very slowly, making it difficult to prepare the target metal oxide (A).

[0071] The hydrolysis-condensation product of compound (E) can be produced from specific raw materials by, for example, a method used in a known sol-gel method. The raw material can be at least one selected from the group consisting of compound (E), a partial hydrolyzate of compound (E), a complete hydrolyzate of compound (E), a compound obtained by partial hydrolysis-condensation of compound (E), and a compound obtained by condensing a portion of a complete hydrolyzate of compound (E).

[0072] The metal oxide (A) to be mixed with the inorganic phosphorus compound (BI)-containing material (inorganic phosphorus compound (BI) or a composition containing the inorganic phosphorus compound (BI)) described later preferably contains substantially no phosphorus atoms.

[0073] (Inorganic phosphorus compounds (BI))

[0074] The inorganic phosphorus compound (BI) contains sites capable of reacting with the metal oxide (A). Typically, it contains multiple such sites, preferably 2 to 20. These sites include sites capable of undergoing condensation reactions with functional groups (e.g., hydroxyl groups) present on the surface of the metal oxide (A). Examples include halogen atoms directly bonded to phosphorus atoms and oxygen atoms directly bonded to phosphorus atoms. Functional groups (e.g., hydroxyl groups) present on the surface of the metal oxide (A) are generally bonded to the metal atoms (M) constituting the metal oxide (A).

[0075] Examples of the inorganic phosphorus compound (BI) include phosphoric acid, diphosphoric acid, triphosphoric acid, polyphosphoric acid obtained by condensing 4 or more phosphoric acid molecules, phosphorous acid, phosphonic acid, phosphinous acid, phosphinic acid, trivalent phosphonic acid and other phosphorus-containing oxyacids, and their salts (e.g., sodium phosphate), and their derivatives (e.g., halides (e.g., phosphorus oxychloride), dehydrates (e.g., phosphorus pentoxide)). One type may be used alone, or two or more types may be used in combination. Among them, from the viewpoint of improving the stability of the coating liquid (S) described later and the gas barrier properties of the obtained multilayer structure, it is preferred to use phosphoric acid alone or in combination with phosphoric acid and other inorganic phosphorus compounds (BI). When phosphoric acid and other inorganic phosphorus compounds (BI) are used in combination, it is preferred that 50 mol% or more of the inorganic phosphorus compound (BI) be phosphoric acid.

[0076] (Reaction product (D))

[0077] The reaction product (D) is obtained by reacting the metal oxide (A) with the inorganic phosphorus compound (BI). Compounds produced by reacting the metal oxide (A), the inorganic phosphorus compound (BI), and further other compounds are also included in the reaction product (D).

[0078] In the infrared absorption spectrum of layer (Y), 800~1400cm -1 The maximum absorption wave number in the region is preferably between 1080 and 1130 cm -1 For example, in the process of forming the reaction product (D) by reacting the metal oxide (A) with the inorganic phosphorus compound (BI), the metal atom (M) derived from the metal oxide (A) and the phosphorus atom (P) derived from the inorganic phosphorus compound (BI) form a bond represented by MOP via the oxygen atom (O). As a result, a characteristic absorption band derived from the bond is generated in the infrared absorption spectrum of the reaction product (D). At 1080-1130 cm -1 When a characteristic absorption band based on the MOP bond is observed in the region of 800 to 1400 cm-1, the obtained multilayer structure exhibits excellent gas barrier properties. In particular, this characteristic absorption band is observed in the region of 800 to 1400 cm-1, where absorption derived from the bond between various atoms and oxygen atoms is generally observed. -1 When the absorption is strongest in the region of , the obtained multilayer structure exhibits more excellent gas barrier properties.

[0079] On the other hand, when a metal compound such as a compound (E) or a metal salt is pre-mixed with an inorganic phosphorus compound (BI) and then subjected to hydrolysis and condensation, the metal atoms derived from the metal compound and the phosphorus atoms derived from the inorganic phosphorus compound (BI) are substantially uniformly mixed and reacted to form a complex. In this case, in the infrared absorption spectrum, the wavelength of the complex is 800 to 1400 cm -1 The maximum absorption wave number in the region will deviate from 1080 to 1130 cm -1 range.

[0080] In the infrared absorption spectrum of layer (Y), from the viewpoint of the gas barrier properties of the obtained multilayer structure, 800 to 1400 cm -1 The half-value width of the maximum absorption band in the region of -1 Below, more preferably 150cm -1 Below, more preferably 100cm -1 Below, particularly preferably 50cm -1 the following.

[0081] The infrared absorption spectrum of layer (Y) can be measured using a Fourier transform infrared spectrophotometer (Spectrum One manufactured by Parkin Elmer) at 800 to 1400 cm -1The measurement area is measured using the attenuated total reflectance method. If the aforementioned methods are not feasible, measurement can be performed using, but not limited to, reflectance measurement methods such as reflection absorption, external reflection, and attenuated total reflectance, or transmission measurement methods such as scraping the layer (Y) from the multilayer structure, the Neujoer method, and the tablet method.

[0082] In addition, the layer (Y) may partially contain the metal oxide (A) and / or the inorganic phosphorus compound (BI) which do not participate in the reaction.

[0083] In layer (Y), the molar ratio of metal atoms constituting the metal oxide (A) to phosphorus atoms derived from the inorganic phosphorus compound (BI) is preferably in the range of [metal atoms constituting the metal oxide (A)]:[phosphorus atoms derived from the inorganic phosphorus compound (BI)] = 1.0:1.0 to 3.6:1.0, and more preferably in the range of 1.1:1.0 to 3.0:1.0. Within this range, excellent gas barrier properties can be achieved. This molar ratio of layer (Y) can be adjusted by the mixing ratio of the metal oxide (A) and the inorganic phosphorus compound (BI) in the coating liquid (S) used to form layer (Y). This molar ratio of layer (Y) is usually the same as that of the coating liquid (S).

[0084] Layer (Y) may contain other components in addition to the above-mentioned components. Examples of other components that may be contained in layer (Y) include a polymer (F) having at least one functional group selected from a carbonyl group, a hydroxyl group, a carboxyl group, a carboxylic anhydride group, and a salt of a carboxyl group (hereinafter sometimes referred to as "polymer (F)"), an organophosphorus compound (BO), a resin composition (V) containing a crosslinking agent, inorganic acid metal salts such as carbonates, hydrochlorides, nitrates, bicarbonates, sulfates, bisulfates, and borates; organic acid metal salts such as oxalates, acetates, tartrates, and stearates; metal complexes such as cyclopentadienyl metal complexes (e.g., titanocene) and cyanometallic complexes (e.g., Prussian blue); layered clay compounds, crosslinking agents, polymer compounds other than polymer (F), plasticizers, antioxidants, ultraviolet absorbers, and flame retardants. The content of the aforementioned other components in layer (Y) of the multilayer structure is preferably 50% by mass or less, more preferably 20% by mass or less, further preferably 10% by mass or less, and particularly preferably 5% by mass or less. It may be 4% by mass or less, 3% by mass or less, 2% by mass or less, 1% by mass or less, or 0% by mass (excluding other components). From the viewpoint of achieving higher clarity, the multilayer structure of the present invention preferably contains a low content of other components.

[0085] (Polymer (F))

[0086] The polymer (F) has at least one functional group selected from the group consisting of a carbonyl group, a hydroxyl group, a carboxyl group, a carboxylic acid anhydride group, and a salt of a carboxyl group. The polymer (F) is preferably a polymer having at least one functional group selected from the group consisting of a hydroxyl group and a carboxyl group.

[0087] Examples of the polymer (F) include polyethylene glycol; polyvinyl alcohol; modified polyvinyl alcohol containing 1 to 50 mol% of α-olefin units having 4 or fewer carbon atoms; polyvinyl acetal (polyvinyl butyral, etc.); polysaccharides such as cellulose and starch; (meth)acrylic acid polymers such as polyhydroxyethyl (meth)acrylate, poly(meth)acrylic acid, and ethylene-acrylic acid copolymers; and maleic acid polymers such as hydrolyzates of ethylene-maleic anhydride copolymers, hydrolyzates of styrene-maleic anhydride copolymers, and hydrolyzates of isobutylene-maleic anhydride alternating copolymers. Among these, polyethylene glycol and polyvinyl alcohol polymers are preferred.

[0088] The polymer (F) may be a homopolymer of a monomer having a polymerizable group, a copolymer of two or more monomers, or a copolymer of a monomer having at least one functional group selected from a carbonyl group, a hydroxyl group, a carboxyl group, a carboxylic anhydride group, and a salt of a carboxyl group and a monomer not having such a functional group. It should be noted that two or more polymers (F) may be mixed and used as the polymer (F).

[0089] The molecular weight of polymer (F) is not particularly limited. However, in order to obtain a multilayer structure having superior gas barrier properties and mechanical strength, the weight average molecular weight of polymer (F) is preferably 5,000 or greater, more preferably 8,000 or greater, and even more preferably 10,000 or greater. The upper limit of the weight average molecular weight of polymer (F) is not particularly limited, but is, for example, 1,500,000 or less.

[0090] From the viewpoint of maintaining a good appearance of the multilayer structure, the content of polymer (F) in layer (Y) is preferably less than 50% by mass, more preferably 20% by mass or less, further preferably 10% by mass or less, based on the mass of layer (Y), and may be 0% by mass. Polymer (F) may or may not react with the components in layer (Y).

[0091] (Organophosphorus compounds (BO))

[0092] The organic phosphorus compound (BO) is preferably a polymer (BOa) having a plurality of phosphorus atoms or an organic phosphorus compound (BOb).

[0093] (Polymer having multiple phosphorus atoms (BOa))

[0094] Examples of the functional groups containing phosphorus atoms possessed by the polymer (BOa) include phosphoric acid groups, phosphorous acid groups, phosphonic acid groups, phosphinous acid groups, phosphinic acid groups, trivalent phosphonic acid groups, and functional groups derived therefrom (e.g., salts, (partial) ester compounds, halides (e.g., chlorides), and dehydrates). Among these, phosphoric acid groups and phosphonic acid groups are preferred, and phosphonic acid groups are more preferred.

[0095] Examples of polymer (BOa) include polymers of phospho(meth)acrylates such as 6-[(2-phosphoacetyl)oxy]hexyl acrylate, 2-phosphoethyl methacrylate, phosphomethyl methacrylate, 11-phosphoundecyl methacrylate, and 1,1-diphosphoethyl methacrylate; polymers of vinylphosphonic acids such as vinylphosphonic acid, 2-propylene-1-phosphonic acid, 4-vinylbenzylphosphonic acid, and 4-vinylphenylphosphonic acid; polymers of vinylphosphinic acids such as vinylphosphinic acid and 4-vinylbenzylphosphinic acid; and phosphorylated starch. Polymer (BOa) may be a homopolymer of a monomer having at least one functional group containing a phosphorus atom, or a copolymer of two or more monomers. Furthermore, polymers formed from a single monomer may be used in combination as polymer (BOa). Preferred polymers include polymers of phospho(meth)acrylates and polymers of vinylphosphonic acids, more preferred are polymers of vinylphosphonic acids, and even more preferred are polyvinylphosphonic acid. Alternatively, the polymer (BOa) can be obtained by homopolymerizing or copolymerizing a vinylphosphonic acid derivative such as a vinylphosphonic acid halide or a vinylphosphonic acid ester, followed by hydrolysis.

[0096] In addition, the polymer (BOa) may be a copolymer of a monomer having at least one functional group containing a phosphorus atom and another vinyl monomer. Examples of other vinyl monomers copolymerizable with the monomer having a functional group containing a phosphorus atom include (meth)acrylic acid, (meth)acrylates, acrylonitrile, methacrylonitrile, styrene, core-substituted styrenes, alkyl vinyl ethers, alkyl vinyl esters, perfluoroalkyl vinyl ethers, perfluoroalkyl vinyl esters, maleic acid, maleic anhydride, fumaric acid, itaconic acid, maleimide, and phenylmaleimide. Among these, (meth)acrylates, acrylonitrile, styrene, maleimide, and phenylmaleimide are preferred.

[0097] In order to obtain a multilayer structure having excellent bending resistance, the proportion of structural units derived from monomers having functional groups containing phosphorus atoms in all structural units of the polymer (BOa) is preferably 10 mol% or more, more preferably 40 mol% or more, further preferably 70 mol% or more, particularly preferably 90 mol% or more, and can be 100 mol%.

[0098] The molecular weight of the polymer (BOa) is not particularly limited, but the number average molecular weight is preferably in the range of 1000 to 100000. When the number average molecular weight is within this range, it is possible to achieve both a high level of improvement in the flexural resistance of the multilayer structure of the present invention and viscosity stability of the coating liquid (S) when using the coating liquid (S) described below.

[0099] When the polymer (BOa) is included in layer (Y) of the multilayer structure, the ratio WBOa / WBI of the mass WBI of the inorganic phosphorus compound (BI) to the mass WBOa of the polymer (BOa) in layer (Y) preferably satisfies the relationship 0.01 / 99.99 ≤ WBOa / WBI < 6.00 / 94.00. From the viewpoint of excellent barrier properties, the ratio more preferably satisfies the relationship 0.10 / 99.90 ≤ WBOa / WBI < 4.50 / 95.50, further preferably 0.20 / 99.80 ≤ WBOa / WBI < 4.00 / 96.00, and particularly preferably 0.50 / 99.50 ≤ WBOa / WBI < 3.50 / 96.50. That is, it is preferred to use a large amount of WBI greater than 94.00 and less than 99.99, rather than a minute amount of WBOa greater than 0.01 and less than 6.00. Even if the inorganic phosphorus compound (BI) and / or the organic phosphorus compound (BOa) in the layer (Y) reacts, the portion of the inorganic phosphorus compound (BI) and / or the organic phosphorus compound (BOa) constituting the reaction product (D) is considered to be the inorganic phosphorus compound (BI) and / or the organic phosphorus compound (BOa). In this case, the mass of the inorganic phosphorus compound (BI) and / or the organic phosphorus compound (BOa) used to form the reaction product (D) (the mass of the inorganic phosphorus compound (BI) and / or the organic phosphorus compound (BOa) before the reaction) is included in the mass of the inorganic phosphorus compound (BI) and / or the organic phosphorus compound (BOa) in the layer (Y).

[0100] (Organophosphorus compound (BOb))

[0101] In the organophosphorus compound (BOb), the phosphorus atom to which at least one hydroxyl group is bonded is bonded to the polar group via an alkylene chain or polyoxyalkylene chain having 3 to 20 carbon atoms. The organophosphorus compound (BOb) has lower surface free energy than the metal oxide (A), the inorganic phosphorus compound (BI), and their reaction product (D), and segregates toward the surface during the formation of the precursor of layer (Y). As a result, the flexural resistance of the multilayer structure of the present invention and the adhesion between layer (Y) and the layer to be directly laminated may be improved.

[0102] Examples of the organophosphorus compound (BOb) include 3-hydroxypropylphosphonic acid, 4-hydroxybutylphosphonic acid, 5-hydroxypentylphosphonic acid, 6-hydroxyhexylphosphonic acid, 7-hydroxyheptylphosphonic acid, 8-hydroxyoctylphosphonic acid, 9-hydroxynonylphosphonic acid, 10-hydroxydecylphosphonic acid, 11-hydroxyundecylphosphonic acid, 12-hydroxydodecylphosphonic acid, 13-hydroxytridecylphosphonic acid, 14-hydroxytetradecylphosphonic acid, 15-hydroxypentadecylphosphonic acid, 16-hydroxyhexadecylphosphonic acid, and the like. phosphonic acid, 17-hydroxyheptadecylphosphonic acid, 18-hydroxyoctadecylphosphonic acid, 19-hydroxynonadecylphosphonic acid, 20-hydroxyeicosylphosphonic acid, 3-hydroxypropyl dihydrogen phosphate, 4-hydroxybutyl dihydrogen phosphate, 5-hydroxypentyl dihydrogen phosphate, 6-hydroxyhexyl dihydrogen phosphate, 7-hydroxyheptyl dihydrogen phosphate, 8-hydroxyoctyl dihydrogen phosphate, 9-hydroxynonyl dihydrogen phosphate, 10-hydroxydecyl dihydrogen phosphate, 11-hydroxyundecyl dihydrogen phosphate, 12-hydroxydecyl dihydrogen phosphate 1-Hydroxydodecyl phosphate, 13-Hydroxytridecyl dihydrogen phosphate, 14-Hydroxytetradecyl dihydrogen phosphate, 15-Hydroxypentadecyl dihydrogen phosphate, 16-Hydroxyhexadecyl dihydrogen phosphate, 17-Hydroxyheptadecyl dihydrogen phosphate, 18-Hydroxyoctadecyl dihydrogen phosphate, 19-Hydroxynonadecyl dihydrogen phosphate, 20-Hydroxyeicosyl dihydrogen phosphate, 3-Carboxypropylphosphonic acid, 4-Carboxybutylphosphonic acid, 5-Carboxypentylphosphonic acid, 6-Carboxyhexylphosphonic acid Phosphonic acid, 7-carboxyheptylphosphonic acid, 8-carboxyoctylphosphonic acid, 9-carboxynonylphosphonic acid, 10-carboxydecylphosphonic acid, 11-carboxyundecylphosphonic acid, 12-carboxydodecylphosphonic acid, 13-carboxytridecylphosphonic acid, 14-carboxytetradecylphosphonic acid, 15-carboxypentadecylphosphonic acid, 16-carboxyhexadecylphosphonic acid, 17-carboxyheptadecylphosphonic acid, 18-carboxyoctadecylphosphonic acid, 19-carboxynonadecylphosphonic acid, 20-carboxyeicosylphosphonic acid, etc. These may be used alone or in combination of two or more.

[0103] When the layer (Y) of the multilayer structure contains the organic phosphorus compound (BOb), the ratio MBOb / MBI of the number of moles of the organic phosphorus compound (BOb) MBOb to the number of moles of the inorganic phosphorus compound (BI) MBI in the layer (Y) preferably satisfies 1.0×10 -4 ≤MBOb / MBI≤2.0×10 -2 The relationship is more preferably 3.5×10 -4 ≤MBOb / MBI≤1.0×10 -2 The relationship between 5.0×10 -4 ≤MBOb / MBI≤6.0×10 -3 relationship.

[0104] When layer (Y) contains an organophosphorus compound (BOb), the C / Al ratio within 5 nm of the surface of layer (Y) on the side not in contact with substrate (X) of the multilayer structure, as measured by X-ray photoelectron spectroscopy (XPS), is preferably in the range of 0.1 to 15.0, more preferably in the range of 0.3 to 10.0, and particularly preferably in the range of 0.5 to 5.0. By adjusting the C / Al ratio on the surface of layer (Y) to be within the aforementioned range, the adhesion between layer (Y) and the adjacent layer may be improved.

[0105] (Resin composition (V) containing a cross-linking agent)

[0106] By making layer (Y) include the resin composition (V) containing a crosslinking agent, the bending resistance sometimes becomes good. The resin composition (V) containing a crosslinking agent is composed of a resin containing a hydroxyl group and a crosslinking agent. As the resin containing a hydroxyl group, epoxy resins containing a hydroxyl group, polyester resins containing a hydroxyl group, (meth) acrylic resins containing a hydroxyl group, polyurethane resins containing a hydroxyl group, vinyl alcohol resins, polysaccharides, etc. can be listed, wherein, preferably vinyl alcohol resins or polysaccharides are included, more preferably vinyl alcohol resins are included, and further preferably polyvinyl alcohol resins are included. As the crosslinking agent, silicon compounds, organic titanium compounds or organic zirconium compounds with glycidyl groups can be suitably used. The mass ratio of the resin containing a hydroxyl group to the crosslinking agent (resin containing a hydroxyl group / crosslinking agent) is preferably 2.0 or more and 200 or less, more preferably 9.0 or more and 60 or less.

[0107] The thickness of layer (Y) (when the multilayer structure has more than two layers (Y), the total thickness of each layer (Y)) is preferably 0.05 to 4.0 μm, more preferably 0.1 to 2.0 μm. By thinning layer (Y), the dimensional change of the multilayer structure during processing such as printing and lamination can be suppressed to a low level. In addition, since the flexibility of the multilayer structure is increased, its mechanical properties can also be made close to the mechanical properties of the substrate itself. When the multilayer structure of the present invention has more than two layers (Y), from the viewpoint of gas barrier properties, the thickness of each layer (Y) is preferably 0.05 μm or more. The thickness of layer (Y) can be controlled by the concentration of the coating liquid (S) described later for forming layer (Y) or its coating method. The thickness of layer (Y) can be measured by observing the cross section of the multilayer structure using a scanning electron microscope or a transmission electron microscope.

[0108] The surface concavo-convexity measured by white light interferometry in layer (Y) is preferably less than 70 nm, more preferably less than 65 nm, and further preferably less than 60 nm. If the surface concavo-convexity of layer (Y) is less than 70 nm, the clarity of the multilayer structure is further improved. The details of the method for making the surface concavo-convexity of layer (Y) less than 70 nm are described later. It is particularly important to apply the coating liquid (S) with a viscosity of 400 mPa·s or more and 5000 mPa·s or less using a substrate (X) having high image clarity and smoothness. The surface concavo-convexity may be more than 1 nm, more than 5 nm, more than 10 nm, more than 20 nm, or more than 30 nm.

[0109] The surface roughness of layer (Y) was measured using a scanning white interference microscope as the difference between the highest and lowest points in a 2.5 mm x 2.5 mm measurement range. The surface roughness of layer (Y) was the average of the measured values at 10 locations within the measurement range.

[0110] The surface irregularities of layer (Y) are the irregularities of the surface of layer (Y) adjacent to substrate (X) and opposite to substrate (X). When layer (Y) is located at the outermost layer of the multilayer structure, the surface irregularities of layer (Y) may be the irregularities of the exposed surface of layer (Y).

[0111] The number of layers (Y) may be one or two or more. The presence of two or more layers (Y) tends to improve barrier properties. When two or more layers (Y) are present, the lamination method is not particularly limited. The layers (Y) may be directly disposed on one or both sides of the substrate (X), or a multilayer structure including the layers (Y) may be bonded together using the adhesive layer (I) described below.

[0112] (Layer(W))

[0113] The multilayer structure of the present invention may include a layer (W) comprising at least one selected from a polymer (F), an organophosphorus compound (BO), and a crosslinking agent-containing resin composition (V) and may be directly laminated on the surface of layer (Y) opposite to the substrate (X). The inclusion of layer (W) may improve flex resistance or adhesion to the adhesive layer (I) described later. From the perspective of clarity of the multilayer structure, it may be preferable not to include layer (W).

[0114] When the multilayer structure of the present invention comprises layer (W), it is preferred that layer (W) and layer (Y) are directly laminated. Suitable embodiments of the polymer (F), organophosphorus compound (BO), and crosslinking agent-containing resin composition (V) that can be contained in layer (W) are as described above.

[0115] Layer (W) may further contain other components, including, for example, inorganic acid metal salts such as carbonates, hydrochlorides, nitrates, bicarbonates, sulfates, bisulfates, and borates; organic acid metal salts such as oxalates, acetates, tartrates, and stearates; metal complexes such as cyclopentadienyl metal complexes (e.g., titanocene) and cyanometallic complexes (e.g., Prussian blue); layered clay compounds; crosslinking agents; polymer compounds other than polymer (BOa) and polymer (F); plasticizers; antioxidants; ultraviolet absorbers; flame retardants; etc. The content of these other components in layer (W) is preferably 20% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and may be 2% by mass or less, 1% by mass or less, or 0% by mass (excluding other components).

[0116] When the multilayer structure of the present invention includes a layer (W), the thickness thereof is preferably 0.005 μm or more from the viewpoint of further improving the bending resistance of the multilayer structure of the present invention. The upper limit of the thickness of the layer (W) is not particularly limited, but the effect of improving the bending resistance is saturated when the thickness is 1.0 μm or more. Therefore, setting the upper limit of the thickness of the layer (W) to 1.0 μm is economically preferred.

[0117] [Adhesive layer (AC)]

[0118] The multilayer structure of the present invention may include an adhesive layer (AC) between the substrate (X) and the layer (Y). The presence of the adhesive layer (AC) may improve the adhesion between the substrate (X) and the layer (Y). In particular, when the substrate (X) has a surface layer, the adhesive layer (AC) is preferably provided between the surface layer and the layer (Y), and more preferably, the adhesive layer (AC) is provided after the surface layer has been surface-treated.

[0119] The adhesive constituting the adhesive layer (AC) is not particularly limited as long as it has adhesion between the substrate (X) and the layer (Y), and examples thereof include polyurethane adhesives and polyester adhesives. The adhesiveness can sometimes be further improved by adding a small amount of additives such as known silane coupling agents to these adhesives. Examples of silane coupling agents include those having reactive groups such as isocyanate groups, epoxy groups, amino groups, urea groups, and mercapto groups.

[0120] As the polyurethane adhesive, a known adhesive can be used, and preferably a two-component polyurethane adhesive obtained by mixing and reacting a polyisocyanate component and a polyol component can be used. As the two-component polyurethane adhesive, commercially available products can be used, for example, TAKELACK (registered trademark) and TAKENET (registered trademark) manufactured by Mitsui Chemicals, Inc. can be mentioned.

[0121] As the polyester adhesive, a known adhesive can be used. Commercially available products include, for example, Elite (registered trademark) KT-0507, KT-8701, KT-8803, KT-9204, KA-5034, KA-3556, KA-1449, KA-5071S, and KZA-1449S (all manufactured by Unitech Co., Ltd.); BioNal (registered trademark) MD-1200 and BioNal MD-1480 (all manufactured by Toyobo Co., Ltd.); and Passretin A124GP and Passretin A684G (manufactured by Takamatsu Oil & Fats Co., Ltd.). The addition of a vinyl alcohol resin, particularly polyvinyl alcohol, to the polyester adhesive can sometimes further enhance adhesion. When using vinyl alcohol resin and polyester resin at the same time, from the viewpoint of maintaining good adhesion and showing higher peel strength, the mass ratio (vinyl alcohol resin / polyester resin) is preferably 1 / 99 or more and 50 / 50 or less. From the viewpoint of affinity with vinyl alcohol resin, polyester resin is preferably a polyester resin having a carboxyl group. In addition, when used as an adhesive, polyester resin is preferably an aqueous dispersion. By making the polyester resin an aqueous dispersion, the affinity with the polyvinyl alcohol resin tends to become better. The thickness of the adhesive layer (AC) is preferably 0.001 to 10.0 μm, more preferably 0.01 to 5 μm.

[0122] (Other layers (J))

[0123] The multilayer structure of the present invention may include another layer (J) to improve various properties (e.g., heat sealability, barrier properties, and mechanical properties). Such a multilayer structure of the present invention can be produced, for example, by laminating layer (Y) (optionally via adhesive layer (AC)) on substrate (X), and then adhering or forming the other layer (J) directly or via adhesive layer (I) described below. Examples of the other layer (J) include, but are not limited to, ink layers, polyolefin layers, and thermoplastic resin layers such as ethylene-vinyl alcohol copolymer resin layers.

[0124] When the multilayer structure of the present invention includes an ink layer, the ink layer may be, for example, a coating obtained by drying a liquid containing a polyurethane resin containing a pigment (e.g., titanium dioxide) dispersed in a solvent. Alternatively, the ink layer may be a coating obtained by drying an ink containing a non-pigmented polyurethane resin or other resin as a main agent, or a resist for forming electronic circuit wiring. The ink layer may be applied by various coating methods, including gravure printing, wire bar coating, spin coating, and die coating. The thickness of the ink layer is preferably 0.5 to 10.0 μm, more preferably 1.0 to 4.0 μm.

[0125] By making the outermost layer of the multilayer structure of the present invention a polyolefin layer, it is possible to impart heat sealability to the multilayer structure or improve the mechanical properties of the multilayer structure. From the viewpoints of improving heat sealability, mechanical properties, etc., the polyolefin is preferably polypropylene or polyethylene. In addition, in order to improve the mechanical properties of the multilayer structure, it is preferred to stack at least one film selected from a film comprising a polyester, a film comprising a polyamide, and a film comprising a polymer containing a hydroxyl group. From the viewpoint of improving mechanical properties, the polyester is preferably polyethylene terephthalate, the polyamide is preferably nylon-6, and the polymer containing a hydroxyl group is preferably ethylene-vinyl alcohol copolymer.

[0126] The other layer (J) may be a layer formed by extrusion coating lamination. The extrusion coating lamination method that can be used in the present invention is not particularly limited, and a known method can be used. In a typical extrusion coating lamination method, a laminated film is produced by feeding a molten thermoplastic resin into a T-die and cooling the thermoplastic resin removed from the flat slit of the T-die.

[0127] Examples of extrusion coating lamination methods other than the aforementioned single-layer lamination method include sandwich lamination and tandem lamination. Sandwich lamination involves extruding a molten thermoplastic resin onto one substrate, feeding a second substrate from another unwinder (winder), and laminating the resulting laminate. Tandem lamination involves connecting two single-layer laminators to produce a five-layer laminate at once.

[0128] [Adhesive layer (I)]

[0129] In the multilayer structure of the present invention, an adhesive layer (I) can sometimes be used to improve the adhesion with other components (such as other layers (J), etc.). The adhesive layer (I) can be composed of an adhesive resin. As an adhesive resin for improving the adhesion with the aforementioned other components, it is preferably a two-component reactive polyurethane adhesive in which a polyisocyanate component and a polyol component are mixed and reacted. In addition, by adding a small amount of additives such as a known silane coupling agent to the anchor coating agent or the adhesive, the adhesion can sometimes be further improved. As the silane coupling agent, for example, silane coupling agents with reactive groups such as isocyanate groups, epoxy groups, amino groups, urea groups, and mercapto groups can be listed, but are not limited thereto. By bonding with other components, when the multilayer structure of the present invention is subjected to processing such as printing or lamination, it is sometimes possible to more effectively suppress the deterioration of gas barrier properties or appearance, and then it is possible to improve the drop strength of the packaging material etc. obtained using the multilayer structure of the present invention.

[0130] [Configuration of Multilayer Structure]

[0131] In the multilayer structure of the present invention, at least one set of substrate (X) and layer (Y) is laminated adjacent to each other. The substrate (X) and layer (Y) may be laminated directly or via an adhesive layer (AC). When the substrate (X) has a surface layer and the layer (Y) is provided on the surface layer, the substrate (X) and layer (Y) are preferably laminated via the adhesive layer (AC). When the substrate (X) does not have a surface layer, the substrate (X) and layer (Y) are preferably laminated directly.

[0132] The following are examples of the multilayer structure of the present invention, but the multilayer structure of the present invention is not limited to these. The structure can be a combination of multiple of each specific example. Here, " / " means lamination via an adhesive layer or direct lamination.

[0133] (1) Layer (Y) / Substrate (X)

[0134] (2) Layer (Y) / Substrate (X) / Layer (Y)

[0135] (3) Base material (X) / layer (Y) / layer (Y) / base material (X)

[0136] (4) Layer (Y) / Substrate (X) / Substrate (X) / Layer (Y)

[0137] (5) Layer (Y) / Substrate (X) / Layer (Y) / Substrate (X)

[0138] (6) Layer (Y) / Substrate (X) / Layer (Y) / Substrate (X) / Layer (Y)

[0139] In the above examples, the substrate (X) preferably comprises a PET layer. Alternatively, it may further comprise another layer (J). In the case of comprising another layer (J), the other layer (J) may be laminated on the layer (Y) or the substrate (X) via an adhesive layer (I).

[0140] [Physical Properties of Multilayer Structure]

[0141] The L of the multilayer structure of the present invention measured in accordance with JIS Z 8722: 2009 ＊ a ＊ b ＊ a* value and b value of the color system ＊ The values are each not less than -0.8, preferably not less than -0.75, and more preferably not less than -0.7. ＊ Value and the aforementioned b ＊ When the value is less than -0.8, the clarity of the obtained multilayer structure tends to decrease. ＊ The lower limit of the value and the aforementioned b ＊ The lower limit of the value can be the same value or different values. ＊ Value and b ＊The values are each 0.8 or less, preferably 0.75 or less, and more preferably 0.7 or less. ＊ Value and b ＊ When the value exceeds 0.8, the clarity of the obtained multilayer structure tends to decrease. ＊ The upper limit of the value and the aforementioned b ＊ The upper limit of the value can be the same value or different values. ＊ Value and b ＊ The difference in values (a ＊ value-b ＊ The value) is preferably -1.0 or more and 1.0 or less. ＊ Value and b ＊ The difference in values is 1.0 or more and 1.0 or less, and the color balance is achieved, and there is a tendency that a multilayer structure with better clarity can be obtained. ＊ Value and b ＊ The value is an average of five measured values obtained in accordance with JIS Z 8722:2009.

[0142] The multilayer structure of the present invention may satisfy the following condition 1.

[0143] (Condition 1)

[0144] In the brightness analysis in which the reflected light observed when the multilayer structure is moved at a certain speed in the MD direction while the multilayer structure is irradiated with a white light source is intermittently measured with a line sensor camera, the white light source is irradiated from one side of the multilayer structure at an angle of 25° relative to the vertical direction of the multilayer structure, and the line sensor camera measures the reflected light at the same side as the white light source and at an angle of -30° relative to the vertical direction of the multilayer structure. For the obtained brightness, a baseline correction is performed by fitting the brightness values of a range of 12 mm in width (TD direction) at the center point of the MD direction of the measurement range using the least squares method, and the minimum value of the standard deviation of the brightness value calculated from the baseline-corrected value is less than 1.2. When the multilayer structure satisfies condition 1, for example, when used as a protective sheet for an electronic device, the clarity is further improved. The details of the method for adjusting the multilayer structure to meet condition 1 are described later, and the image clarity of the substrate (X) is high, and for the use of a corona treatment device at 130 W min / m 2 It is particularly important that a 2.0 μL drop of coating solution (S) be added to the treated surface of a polyethylene terephthalate film at 23°C and 50% RH, and that the contact angle of the drop be between 20° and 35° after 2 seconds. The standard deviation of brightness values obtained under condition 1 may sometimes be simply expressed as "standard deviation of brightness values."

[0145] The minimum standard deviation of the brightness values of the multilayer structure of the present invention is preferably 1.2 or less, more preferably 1.1 or less, and even more preferably 1.0 or less. Setting the minimum standard deviation of the brightness values to 1.2 or less tends to further improve the clarity of the multilayer structure. The standard deviation of the brightness values may be 0.6 or greater.

[0146] (Method for evaluating the standard deviation of brightness of a multilayer structure)

[0147] In the multilayer structure of the present invention, the standard deviation of brightness can be evaluated by the following method.

[0148] 1. Determination

[0149] A white light source was used to illuminate the multilayer structure at an angle of 25° relative to the vertical direction. A line sensor camera was then placed on the same side as the white light source and at an angle of -30° relative to the vertical direction of the multilayer structure. The camera was adjusted to focus on the multilayer structure. The multilayer structure was moved at a constant speed in the MD direction, and the brightness of the reflected light observed during movement was intermittently measured using the line sensor camera.

[0150] 2. Analysis

[0151] The brightness values obtained were fitted to a quadratic function using the least squares method for a width of 12 mm at the center point of the measurement range in the MD direction (TD direction). This was used as the baseline, and baseline correction was performed by calculating the difference between the value fitted using the least squares method and the measured value. The minimum standard deviation of the brightness after baseline correction was set as the standard deviation of the brightness of the multilayer structure. This analysis can be used to evaluate brightness differences in films caused by fine spots that are difficult to detect visually.

[0152] The water vapor transmission rate of the multilayer structure of the present invention at 40°C and 90% RH measured in accordance with ISO15106-3:2003 is preferably 1×10 -2 g / m 2 Less than 9 × 10 -3 g / m 2 Less than 7 × 10 days, more preferably -3 g / m 2 · days or less. By making the water vapor transmission rate 1×10 -2 g / m 2 · days or less, articles obtained using the multilayer structure (for example, protective sheets for electronic devices) have excellent moisture resistance and tend to be less susceptible to degradation even in harsh environments.

[0153] The oxygen permeability of the multilayer structure of the present invention at 20°C and 85% RH measured in accordance with ISO15105-2:2003 is preferably 7×10 -2 cc / m 2 ·day·atm or less, more preferably 5×10 -2 cc / m 2 ·day·atm or less, more preferably 2×10 -2 cc / m 2 ·day·atm or less. By making the oxygen permeability 7×10 -2 g / m 2 · days or less, an article obtained using the obtained multilayer structure (for example, a protective sheet for an electronic device) has excellent oxygen barrier properties and tends to be less susceptible to degradation even in a harsh environment.

[0154] [Method for producing a multilayer structure]

[0155] Matters described for the multilayer structure of the present invention are applicable to the production method of the present invention, and therefore, duplicate descriptions may be omitted. In addition, matters described for the production method of the present invention are applicable to the multilayer structure of the present invention.

[0156] As a method for producing the multilayer structure of the present invention, for example, the following production method can be cited, which includes the following steps: step (I), which forms a layer (Y) precursor layer by applying a coating liquid (S) containing a metal oxide (A), an inorganic phosphorus compound (BI) and a solvent to a substrate (X), and then removing the solvent; and step (II), which forms a layer (Y) precursor layer by heat treating the layer (Y) precursor layer. When producing a multilayer structure containing an organophosphorus compound (BO) or a polymer (F), the coating liquid (S) used in step (I) may contain an organophosphorus compound (BO) or a polymer (F) to form a layer (Y) containing the organophosphorus compound (BO) or the polymer (F). A coating liquid (T) containing the organophosphorus compound (BO) or the polymer (F) may be prepared and applied to the surface of the precursor layer of the layer (Y) obtained in step (I) or the surface of the layer (Y) obtained in step (II) in step (III). Alternatively, the organophosphorus compound (BO) or the polymer (F) may be impregnated into the layer (Y). Furthermore, the layer (W) may be provided on the layer (Y). In the case where an adhesive layer (AC) is provided between the substrate (X) and the layer (Y), a step of providing the adhesive layer (AC) on the substrate (X) prior to step (I) may be included.

[0157] [Step (I)]

[0158] In step (I), a coating liquid (S) containing a metal oxide (A), an inorganic phosphorus compound (BI), and a solvent is applied to a substrate (X), and then the solvent is removed to form a layer (Y) precursor layer.

[0159] The coating liquid (S) is obtained by mixing a metal oxide (A), an inorganic phosphorus compound (BI), and a solvent. Specific methods for preparing the coating liquid (S) include: a method of mixing a dispersion of the metal oxide (A) with a solution containing the inorganic phosphorus compound (BI); a method of adding the inorganic phosphorus compound (BI) to the dispersion of the metal oxide (A) and mixing the mixture. The temperature during mixing is preferably 50°C or lower, more preferably 30°C or lower, and even more preferably 20°C or lower. The coating liquid (S) may contain other compounds (e.g., an organic phosphorus compound (BO), a polymer (F)), and may also contain at least one acid compound (Q) selected from acetic acid, hydrochloric acid, nitric acid, trifluoroacetic acid, and trichloroacetic acid, as needed.

[0160] The dispersion of the metal oxide (A) can be prepared, for example, by mixing the compound (E), water, and, if necessary, an acid catalyst and an organic solvent, and subjecting the compound (E) to condensation or hydrolysis condensation, according to a method employed in a known sol-gel method. When the dispersion of the metal oxide (A) is obtained by subjecting the compound (E) to condensation or hydrolysis condensation, the resulting dispersion can be subjected to specific treatment (e.g., dissolution in the presence of the aforementioned acid compound (Q)) as required). The solvent used in preparing the dispersion of the metal oxide (A) is not particularly limited, but is preferably an alcohol such as methanol, ethanol, or isopropanol; water; or a mixed solvent thereof.

[0161] The solvent used in the solution containing the inorganic phosphorus compound (BI) may be appropriately selected depending on the type of the inorganic phosphorus compound (BI), and preferably contains water. The solvent may contain an organic solvent (e.g., alcohols such as methanol) as long as it does not hinder the dissolution of the inorganic phosphorus compound (BI).

[0162] From the viewpoint of storage stability of the coating liquid and coating properties on a substrate, the solid content concentration of the coating liquid (S) is preferably 1 to 20% by mass, more preferably 2 to 15% by mass, and even more preferably 3 to 10% by mass. The solid content concentration can be calculated by, for example, dividing the mass of the solid content remaining after distilling off the solvent of the coating liquid (S) by the mass of the coating liquid (S) provided for treatment.

[0163] The viscosity (I) of the coating liquid (S), as measured using a Brookfield rotational viscometer (SB type viscometer: rotor No. 3, rotation speed: 60 rpm), is preferably 3000 mPa·s or less, more preferably 2500 mPa·s or less, and even more preferably 2000 mPa·s or less at the temperature at the time of coating. By setting this viscosity (I) to 3000 mPa·s or less, the leveling properties of the coating liquid (S) are improved, and a multilayer structure with a more excellent appearance can be obtained. Furthermore, the viscosity (I) of the coating liquid (S) is preferably 50 mPa·s or more, more preferably 100 mPa·s or more, and even more preferably 200 mPa·s or more.

[0164] From the perspective of reducing the surface roughness of layer (Y) to 70 nm or less, the viscosity (II) of the coating liquid (S), as measured using a Brookfield rotational viscometer (SB type viscometer: rotor No. 63, rotation speed 6 rpm), is preferably 5000 mPa·s or less, more preferably 4500 mPa·s or less, and even more preferably 4000 mPa·s or less at the temperature during coating. Furthermore, the viscosity (II) of the coating liquid (S) is preferably 400 mPa·s or greater, more preferably 600 mPa·s or greater, and even more preferably 800 mPa·s or greater. A viscosity of 400 mPa·s or greater tends to improve barrier properties.

[0165] In the coating liquid (S), the molar ratio of aluminum atoms to phosphorus atoms is preferably in the range of aluminum atoms:phosphorus atoms = 1.0:1.0 to 3.6:1.0, more preferably in the range of 1.1:1.0 to 3.0:1.0, and particularly preferably in the range of 1.11:1.00 to 1.50:1.0. The molar ratio of aluminum atoms to phosphorus atoms can be calculated by fluorescent X-ray analysis of a dried product of the coating liquid (S).

[0166] The coating liquid (S) preferably satisfies the following (Condition 2).

[0167] (Condition 2)

[0168] For the use of corona treatment equipment at 130W·min / m 2 A 2.0 μL drop of the coating liquid (S) was added to the treated surface of the polyethylene terephthalate film at 23° C. and 50% RH, and the contact angle of the drop after 2 seconds was 20° or more and 35° or less.

[0169] When the coating liquid (S) satisfies condition 2, the resulting multilayer structure tends to satisfy condition 1. The contact angle is preferably 33° or less, more preferably 31° or less. By setting the contact angle to 35° or less, the leveling properties of the coating liquid (S) are improved, and a multilayer structure with even better clarity tends to be obtained. Furthermore, the contact angle is preferably 22° or greater, more preferably 25° or greater. By setting the contact angle to 20° or greater, barrier properties tend to be further improved.

[0170] The method for adjusting the contact angle to 20° or more and 35° or less is not particularly limited, and it can be achieved, for example, by selecting the solvent of the coating liquid (S).

[0171] The solvent of the coating liquid (S) is not particularly limited. From the perspective of coating properties, it is preferably an alcohol such as methanol, ethanol, or isopropyl alcohol; water; or a mixed solvent thereof, more preferably a mixed solvent of water and an alcohol, and even more preferably a mixed solvent of water and methanol. The ratio of the mixed solvent of water and methanol is preferably a water / methanol ratio of 3.5 / 6.5 or more and 7 / 3 or less. By making the water / methanol ratio 7 / 3 or less, there is a tendency to adjust the contact angle to 20° or more and 35° or less. In addition, by making the water / methanol ratio 3.5 / 6.5 or more, there is a tendency to produce a uniform coating liquid (S).

[0172] The coating liquid (S) is not particularly limited and can be applied by a known method. Examples of the coating method include casting, dipping, roll coating, gravure coating, screen printing, reverse coating, spray coating, kiss coating, die coating, metering rod coating, sealed blade coating, curtain coating, and rod coating.

[0173] The method for removing the solvent after applying the coating liquid (S) (drying treatment) is not particularly limited, and a known drying method can be applied. Examples of the drying method include hot air drying, hot roll contact drying, infrared heating, and microwave heating.

[0174] The drying temperature is preferably lower than the flow start temperature of the substrate (X). The drying temperature after applying the coating liquid (S) is 120°C or more, and can be 120°C or more and less than 180°C, more preferably 120°C or more and less than 165°C, further preferably 120°C or more and less than 150°C, and particularly preferably 120°C or more and less than 140°C. The drying time is not particularly limited, but is preferably 1 second or more and less than 1 hour, and can be 5 seconds or more and less than 15 minutes or 5 seconds or more and less than 300 seconds. In addition, the drying time can be 1 second or more and less than 4 minutes, 5 seconds or more and less than 4 minutes, or 5 seconds or more and less than 3 minutes. If the drying treatment conditions of the coating liquid (S) are within the aforementioned range, there is a tendency to obtain a multilayer structure with better gas barrier properties. The solvent is removed by undergoing the aforementioned drying to form a layer (Y) precursor layer.

[0175] The time from the completion of coating of the coating liquid (S) to the start of heating and drying is 1.8 seconds or more, preferably 2.3 seconds or more, and more preferably 3.0 seconds or more. By making the time from the completion of coating to the start of heating and drying 1.8 seconds or more, the leveling property of the coating liquid (S) is improved, and there is a tendency for a multilayer structure with better clarity to be obtained. In addition, the time from the completion of coating to the start of heating and drying is 9.0 seconds or less, preferably 8.5 seconds or less, and more preferably 8.0 seconds or less. By making the time from the completion of coating to the start of heating and drying 9.0 seconds or less, there is a tendency for the coated surface to become uniform, and there is a tendency for the barrier properties to be improved. It should be noted that when the time from coating to drying is less than 1.8 seconds, a ＊ Value and b ＊ If the value is not greater than -0.8 and less than 0.8, and exceeds 9.0 seconds, it tends to be difficult to form a multilayer structure. Here, when the multilayer structure of the present invention is produced continuously, for example, the time from the completion of coating to the start of heat drying refers to the time from immediately after coating of the coating liquid (S) to the time when the coated portion is exposed to an atmosphere of 120°C or higher (until entering a drying furnace of 120°C or higher).

[0176] When laminating the layer (Y) on both sides of a substrate (X), a coating liquid (S) is generally applied to one side of the substrate (X) and then the solvent is removed to form a first layer (a precursor layer of the first layer (Y)). Subsequently, the coating liquid (S) is applied to the other side of the substrate (X) and then the solvent is removed to form a second layer (a precursor layer of the second layer (Y)). The composition of the coating liquid (S) applied to each side may be the same or different.

[0177] [Step (II)]

[0178] In step (II), the layer (Y) precursor layer formed in step (I) is heat-treated to form layer (Y). In step (II), a reaction to generate a reaction product (D) is carried out. In order to fully carry out the reaction, the heat treatment temperature is preferably 140°C or more, more preferably 170°C or more, further preferably 180°C or more, and particularly preferably 190°C or more. If the heat treatment temperature is low, the time taken to obtain a sufficient reaction rate becomes longer, which becomes a cause of reduced productivity. The heat treatment temperature varies depending on the type of substrate (X). For example, when a thermoplastic resin film formed of a polyamide resin is used as substrate (X), the heat treatment temperature is preferably 270°C or less. In addition, when a thermoplastic resin film formed of a polyester resin is used as substrate (X), the heat treatment temperature is preferably 240°C or less. The heat treatment can be carried out under an air atmosphere, a nitrogen atmosphere, an argon atmosphere, etc. The heat treatment time is preferably 1 second to 1 hour, more preferably 1 second to 15 minutes, and further preferably 5 to 300 seconds.

[0179] Step (II) preferably includes a first heat treatment step (II-1) and a second heat treatment step (II-2). When the heat treatment is performed in two or more stages, the temperature of the second heat treatment (hereinafter referred to as the second heat treatment) is preferably higher than the temperature of the first heat treatment (hereinafter referred to as the first heat treatment), more preferably 15°C or higher, further preferably 20°C or higher, and particularly preferably 30°C or higher.

[0180] In addition, from the viewpoint of obtaining a multilayer structure with good properties, the heat treatment temperature of step (II) (the first heat treatment temperature in the case of two or more stages of heat treatment) is preferably higher than the drying temperature of step (I), preferably 30°C or higher, more preferably 50°C or higher, further preferably 55°C or higher, and particularly preferably 60°C or higher.

[0181] When the heat treatment of step (II) is performed in two or more stages, the temperature of the first heat treatment is preferably 140°C or higher and less than 200°C, and the temperature of the second heat treatment is more preferably 180°C or higher and 270°C or lower. The temperature of the second heat treatment is preferably higher than the first heat treatment temperature, more preferably 15°C or higher, and further preferably 25°C or higher. In particular, when the heat treatment temperature is 200°C or higher, the heat treatment time is preferably 0.1 seconds to 10 minutes, more preferably 0.5 seconds to 5 minutes, and further preferably 1 second to 3 minutes. When the heat treatment temperature is lower than 200°C, the heat treatment time is preferably 1 second to 15 minutes, more preferably 5 seconds to 10 minutes, and further preferably 10 seconds to 5 minutes.

[0182] [Step (III)]

[0183] In the above-mentioned production method, when an organophosphorus compound (BO), a polymer (F), and / or other components are used, the following step (III) may be included: a coating liquid (T) obtained by mixing the organophosphorus compound (BO), the polymer (F), and / or other components, and a solvent is applied to the layer (Y) precursor layer obtained in step (I), the layer (Y) obtained in step (II), or the layer (Y) precursor layer after step (II-1), and then subjected to a drying treatment. When step (III) is performed after step (II-1), step (II-2) is preferably performed after the drying treatment in step (III). In step (III), the amount of coating liquid (T) applied may be increased to form layer (W) on layer (Y).

[0184] The solvent used in the coating liquid (T) may be appropriately selected depending on the types of the organophosphorus compound (BO), polymer (F) and / or other components, and is preferably an alcohol such as methanol, ethanol, or isopropyl alcohol; water; or a mixed solvent thereof.

[0185] From the viewpoint of storage stability and coating properties of the solution, the solid content concentration in the coating solution (T) is preferably 0.01 to 60% by mass, more preferably 0.1 to 50% by mass, and even more preferably 0.2 to 40% by mass. The solid content concentration can be determined by the same method as described for the coating solution (S).

[0186] The method for applying the coating liquid (T) is not particularly limited in the same manner as the coating liquid (S), and a known method can be employed.

[0187] The conditions for the solvent removal method (drying treatment) after applying the coating liquid (T) in step (III) can be the same as the drying treatment conditions after applying the coating liquid (S) in step (I).

[0188] [Step (IV)]

[0189] Prior to step (I), the following step may be included: after surface treatment of the substrate (X) as needed, an adhesive layer (AC) may be provided. More preferably, the following step (IV) may be included: after applying a coating solution (R) comprising a PVA-based resin, a polyester-based resin, and a solvent onto the substrate (X), the solvent is removed to form the adhesive layer (AC).

[0190] The coating liquid (R) can be obtained by directly mixing the PVA resin, the polyester resin, and the solvent, or by mixing a solution or dispersion containing the PVA resin with a solution or dispersion containing the polyester resin. From the perspective of solution homogeneity, it is preferred to mix an aqueous solution of the PVA resin with a dispersion of the polyester resin to obtain the coating liquid (R).

[0191] The solvent used in the coating liquid (R) is not particularly limited, but preferably contains water as the main component and may be water alone. In addition, when containing water as the main component, alcohols such as methanol, ethanol, and isopropyl alcohol are preferably used as other solvents.

[0192] From the viewpoint of storage stability of the coating liquid and coating properties on a substrate, the solid content concentration of the coating liquid (R) is preferably 0.01 to 10% by mass. The solid content concentration can be calculated, for example, by dividing the mass of the solid content remaining after distilling off the solvent of the coating liquid (R) by the mass of the coating liquid (R) provided for treatment.

[0193] The coating liquid (R) is not particularly limited and can be applied by a known method. Examples of the coating method include casting, dipping, roll coating, gravure coating, screen printing, reverse coating, spray coating, kiss coating, die coating, metering rod coating, sealed blade coating, curtain coating, and rod coating.

[0194] The method for removing the solvent from the coating liquid (R) after coating on the substrate (X) is not particularly limited, and a known drying method can be applied. Examples of the drying method include hot air drying, hot roll contact drying, infrared heating, and microwave heating.

[0195] [Protective sheet for electronic devices]

[0196] The protective sheet for the electronic device of the present invention comprises the multilayer structure of the present invention. The protective sheet for the electronic device of the present invention may be composed solely of the multilayer structure of the present invention, or may be composed of the multilayer structure of the present invention and other components. The protective sheet for the electronic device of the present invention can be used, for example, as a protective sheet for protecting the surface of a photoelectric conversion device, an information display device, or a lighting device. The protective sheet for the electronic device of the present invention has high barrier properties and clarity. Therefore, by using the protective sheet of the present invention, it is possible to obtain an electronic device that deteriorates less in harsh environments and has high clarity of transmitted images. For example, in the case of a substrate film for electronic paper, it can be suitably used as a protective material for ink of electronic paper that is easily affected by moisture.

[0197] The protective sheet of the electronic device of the present invention can include a surface protective layer configured on one surface of the multilayer structure. As the surface protective layer, it is preferably a layer formed of a resin having high transparency and not easily damaged. In addition, the surface protective layer of the equipment sometimes used outdoors, such as a solar cell, is preferably formed of a resin with high weather resistance (such as light resistance). In addition, in the case where the surface that needs to transmit light is protected, it is preferably a surface protective layer with high light transmittance. As the material of the surface protective layer (surface protective film), for example, acrylic resins, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, cellulose triacetate, cycloolefin polymers, ethylene-tetrafluoroethylene copolymers (ETFE), polytetrafluoroethylene, 4-fluoroethylene-perchloroalkoxy copolymers, 4-fluoroethylene-6-fluoropropylene copolymers, 2-ethylene-4-fluoroethylene copolymers, poly-3-fluorochloroethylene, polyvinylidene fluoride, polyvinyl fluoride, etc. can be listed.

[0198] To improve the durability of the surface protective layer, various additives (e.g., ultraviolet absorbers) may be added to the surface protective layer. A preferred example of a surface protective layer with high weather resistance is an acrylic resin layer to which an ultraviolet absorber is added. Examples of ultraviolet absorbers include, but are not limited to, benzotriazole-based, benzophenone-based, salicylate-based, cyanoacrylate-based, nickel-based, and triazine-based ultraviolet absorbers. Furthermore, other stabilizers, light stabilizers, antioxidants, and the like may be used in combination.

[0199] Furthermore, in order to improve the durability of the surface protective layer, a weather-resistant coating such as a hard coat may be applied to the surface. The type of coating is not particularly limited, and known materials can be used.

[0200] The structure of the protective sheet is not particularly limited, and for example, the following structure may be preferably used.

[0201] (1) Multilayer structure

[0202] (2) Multilayer structure / adhesive layer / polyethylene terephthalate

[0203] (3) Multilayer structure / adhesive layer / cellulose triacetate

[0204] (4) Multilayer structure / adhesive layer / acrylic

[0205] (5) Multilayer structure / adhesive layer / polycarbonate

[0206] (6) Multilayer structure / adhesive layer / cycloolefin polymer

[0207] (7)ETFE layer / adhesive layer / multilayer structure

[0208] The multilayer structure of the present invention can also be used as a film referred to as a substrate film, such as a substrate film for LCDs, organic EL substrate films, and electronic paper substrate films. In this case, the multilayer structure can serve as both a substrate and a protective sheet. Furthermore, the electronic device protected by the protective sheet is not limited to the aforementioned examples and can include, for example, an IC tag, an optical communication device, a fuel cell, and the like.

[0209] [Electronic equipment]

[0210] An electronic device using the multilayer structure of the present invention generally comprises an electronic device body and a protective sheet for protecting the surface of the electronic device body. The protective sheet is the protective sheet for the electronic device of the present invention.

[0211] The electronic device of the present invention may be a photoelectric conversion device, an information display device, or a lighting device. Examples of photoelectric conversion devices include various solar cells and other photoelectric conversion devices. Examples of information display devices include liquid crystal displays, organic EL displays, plasma displays, electronic paper, and other information display devices. Examples of lighting devices include LED lighting, organic EL lighting, and other lighting devices.

[0212] The electronic device of the present invention can be particularly preferably used as a device comprising an optical element. As the optical element, it is appropriately selected according to the purpose of the electronic device of the present invention. Here, the optical element in the present invention refers to an element having an optical function, and the optical function can include, for example, an information display function, a light-emitting function, etc. When an element having an information display function is used as the aforementioned optical element, the electronic device of the present invention can be used as an information display device, and when an element having a light-emitting function is used as the optical element, the electronic device of the present invention can be used as a light-emitting device (illumination device).

[0213] Examples of the aforementioned optical element having an information display function include liquid crystal cells used in liquid crystal display devices, organic EL elements used in organic EL display devices, and electronic paper elements (e.g., particle migration type, liquid crystal type, electrochemical type) used in electronic paper devices. Here, by using a liquid crystal cell as the aforementioned optical element, the optical device of the present invention forms a liquid crystal display device, by using an organic EL element, it forms an organic EL display device, and by using an electronic paper element, it forms an electronic paper device.

[0214] The liquid crystal cell, organic EL element, and electronic paper element are not particularly limited, and generally known elements can be used.

[0215] Example

[0216] Next, examples are given to more specifically illustrate the present invention, but the present invention is not limited to these examples at all, and personnel with common knowledge in the art can make various modifications within the scope of the technical concept of the present invention. The analysis and evaluation in the following examples and comparative examples are carried out as follows.

[0217] <Materials used in Examples and Comparative Examples>

[0218] PET50: Biaxially stretched polyethylene terephthalate film; manufactured by Toray Industries, Inc., "Lumira (trademark) U403" (trade name), with surface layers on both sides, thickness 50 μm, image clarity 94%

[0219] PET23-A: Biaxially stretched polyethylene terephthalate film; manufactured by Toray Industries, Inc., "Lumira (trademark) U403" (trade name), with surface layers on both sides, thickness 23 μm, image clarity 94%

[0220] PET23-B: Biaxially stretched polyethylene terephthalate film; manufactured by Mitsubishi Chemical Corporation, "Diahoil T600E" (trade name), with a surface layer on one side, thickness 23 μm, image clarity 94%,

[0221] PET23-C: Biaxially stretched polyethylene terephthalate film; manufactured by Hyosung Corporation, "RH210" (trade name), with surface layers on both sides, thickness 23 μm, image clarity 94%

[0222] PET23-D: Biaxially stretched polyethylene terephthalate film; manufactured by Toray Industries, Inc., "Lumira (trademark) S105" (trade name), thickness 23 μm, image clarity 83%

[0223] PET38: Biaxially stretched polyethylene terephthalate film; manufactured by Toray Industries, Inc., "Lumira (trademark) U483" (trade name), with surface layers on both sides, thickness 38 μm, image clarity 94%

[0224] PET75: Biaxially stretched polyethylene terephthalate film; manufactured by Toray Industries, Inc., "Lumira (trademark) U483" (trade name), with surface layers on both sides, thickness 75 μm, image clarity 93%

[0225] PET12: Biaxially stretched polyethylene terephthalate film; manufactured by Toray Industries, Inc., "Lumira (trademark) P60" (trade name), thickness 12 μm, image clarity 82%

[0226] Image clarity was measured according to the method described in the evaluation method (4) described later.

[0227] <Evaluation Method>

[0228] (1) Determination of the maximum absorption wavenumber (Imax) of infrared absorption spectrum

[0229] The layer (Y) of the multilayered structure obtained in the examples and comparative examples was measured by attenuated total reflectance method using a Fourier transform infrared spectrophotometer, and the wavelengths of 800 to 1400 cm -1 The maximum absorption wave number (Imax) in the region is given below. The measurement conditions are as follows.

[0230] Device: Spectrum One manufactured by パーキンエルマー Co., Ltd.

[0231] Measurement mode: Attenuated total reflectance method

[0232] Measurement area: 800-1400cm -1

[0233] (2) Thickness

[0234] The multilayer structures obtained in the Examples and Comparative Examples were cut using a focused ion beam (FIB) to produce sections for cross-sectional observation. The sections were secured to a sample holder using carbon tape and then sputtered with platinum ions for 30 seconds at an accelerating voltage of 30 kV. Cross-sections of the multilayer structures were observed using a field-emission transmission electron microscope, and the thickness of each layer and the total thickness of the multilayer structure were calculated. The measurement conditions are shown below.

[0235] Device: JEM-2100F manufactured by JEOL Ltd.

[0236] Accelerating voltage: 200 kV

[0237] Magnification: 250,000x

[0238] (3) Water vapor transmission rate

[0239] The multilayer structures obtained in the examples and comparative examples were placed in a water vapor transmission rate measuring apparatus and the water vapor transmission rates were measured using the isobaric method in accordance with ISO 15106-3:2003. The measurement conditions are as follows. The water vapor transmission rate is 1×10 -2 g / (m 2 ·days) or less, the water vapor barrier property is judged to be high.

[0240] Device: AQUATRAN manufactured by MOCON

[0241] Temperature: 40℃

[0242] Humidity on the water vapor supply side: 90% RH

[0243] (4) Image clarity

[0244] The substrate (X) used in Examples and Comparative Examples was mounted on an image clarity measuring apparatus, and image clarity was measured in accordance with ISO 17221. The measurement conditions were as follows, and the average value of five measurements was used as the measured value.

[0245] Equipment: Image clarity meter IC-T manufactured by Suga Testing Instruments Co., Ltd.

[0246] Comb width: 0.25mm

[0247] (5) Clarity

[0248] The image display device was placed on the surface of any image display device, with the side of the material laminated with the protective sheet for electronic devices obtained in the Examples and Comparative Examples facing the surface. The clarity of the text displayed on the image display device was evaluated. Clear text was assigned an A, while slightly blurred text edges were assigned a B, and the text was not clearly visible as a whole was assigned a C. Ten panelists evaluated each of these criteria, and the most common rating was used as the clarity rating. If multiple ratings were given, these ratings were recorded together.

[0249] (6) Oxygen permeability

[0250] The multilayer structures obtained in the examples and comparative examples were cut into pieces of 10 mm x 10 mm. The cut multilayer structures were mounted on an oxygen permeability measuring device and the oxygen permeability was measured using an isobaric method. The measurement conditions are as follows. If the oxygen permeability is 0.07 cc / (m 2 ·day·atm) or less, it is judged to have high oxygen barrier properties.

[0251] Device: OX-TRAN2 / 21 manufactured by MOCON

[0252] Temperature: 20℃

[0253] Humidity on oxygen supply side: 85% RH

[0254] Humidity on the carrier gas side: 85% RH

[0255] Carrier gas flow rate: 10mL / min

[0256] Oxygen pressure: 1.0 atm

[0257] Carrier gas pressure: 1.0 atm

[0258] (7) Color

[0259] The multilayer structures obtained in Examples and Comparative Examples were placed in a spectrophotometer and evaluated according to JIS Z 8722:2009. ＊、b ＊ The measurement was performed 5 times, and the average value was taken as the measured value.

[0260] Equipment: Spectrophotometer U-4100 manufactured by Hitachi High-Technologies Co., Ltd.

[0261] Light source: C light source

[0262] <Production Example of Coating Liquid (S-1)>

[0263] 230 parts by mass of distilled water was heated to 70°C while stirring. 88 parts by mass of aluminum triisopropoxide was added dropwise to this distilled water over 1 hour, and the liquid temperature was gradually raised to 95°C. The generated isopropyl alcohol was distilled off to carry out hydrolysis and condensation. 4.0 parts by mass of a 60% by mass aqueous nitric acid solution was added to the resulting liquid, and the mixture was stirred at 95°C for 3 hours to disaggregate the aggregated particles of the hydrolysis-condensation product. The liquid was then concentrated to a solids concentration of 10% by mass, calculated as aluminum oxide, to obtain a solution. 54.29 parts by mass of distilled water was added to 22.50 parts by mass of the resulting solution, and the mixture was stirred until homogeneous, thereby obtaining a dispersion. Next, 4.41 parts by mass of an 85% by mass aqueous phosphoric acid solution was added dropwise while stirring the dispersion while maintaining the liquid temperature at 15°C. Furthermore, 18.80 parts by mass of a methanol solution was added dropwise, and stirring was continued at 15°C until the viscosity reached 1,500 mPa·s, yielding the target coating liquid (S-1). The molar ratio of aluminum atoms to phosphorus atoms in this coating liquid (S-1) was aluminum atoms:phosphorus atoms = 1.15:1.00. The viscosity of the coating liquid (S-1) was measured using a Brookfield rotational viscometer (SB type viscometer: rotor No. 3, rotation speed 60 rpm).

[0264] <Production Example of Coating Liquid (R-1)>

[0265] 4.8 parts by mass of "Kurare Potball (registered trademark) 48-80" PVA was mixed with 95.2 parts by mass of water, and the mixture was stirred at room temperature for 5 hours to dissolve "Kurare Potball (registered trademark) 48-80" to obtain a PVA aqueous solution. Subsequently, 0.8 parts by mass of "Elite (registered trademark) KA-5071S" (manufactured by Unichika Co., Ltd.), a polyester aqueous dispersion, 1.2 parts by mass of the aforementioned PVA aqueous solution, 68.1 parts by mass of water, and 29.9 parts by mass of methanol were mixed and stirred for 1 hour to obtain a coating solution (R-1).

[0266] <Example 1>

[0267] As the substrate (X-1), PET50 was used and the temperature was 130 W·min / m 2To enhance the strength of the substrate (X-1), one surface of the substrate (X-1) was subjected to a surface treatment based on a corona treatment. The coating liquid (R-1) was then continuously applied by gravure coating to a thickness of 10 nm after drying. The coating liquid was dried in a hot air drying oven at 140°C, and then wound into a roll to form an adhesive layer (AC-1) on one surface of the substrate. The adhesive layer (AC-1) formed was continuously applied by gravure coating to a thickness of 0.4 μm after drying. The coating liquid (S-1) was dried in a hot air drying oven at 120°C, and then wound into a roll to form a precursor layer for layer (Y-1). The time from coating to the start of drying is the time from the completion of coating of the coating liquid (S-1) to the moment the multilayer structure enters the hot air drying oven. Next, the other side of the substrate (X-1) was also surface-treated by the same method, and then the precursor layers of the adhesive layer (AC-1) and the layer (Y-1) were formed in sequence. The film forming the precursor layer of the obtained layer (Y-1) was passed through a hot air drying furnace, thereby performing a heat treatment at 180°C for 1 minute, and then wound into a roll. Furthermore, by passing the film forming the precursor layer of the obtained layer (Y-1) through a hot air drying furnace, thereby performing a heat treatment at 210°C for 1 minute, a multilayer structure of layer (Y-1) (0.4μm) / adhesive layer (AC-1) (10nm) / substrate (X-1) (50μm) / adhesive layer (AC-1) (10nm) / layer (Y-1) (0.4μm) was obtained. The layer (Y-1) of the obtained multilayer structure was evaluated according to the methods described in the above-mentioned evaluation methods (1) and (2). In addition, the obtained multilayer structure was evaluated according to the methods described in the above-mentioned evaluation methods (3), (6) and (7). The results are shown in Table 1.

[0268] Six sheets of the obtained multilayer structure were prepared, and an adhesive layer was formed on each side using a two-component polyurethane adhesive ("Takelac (registered trademark) A-1102" manufactured by Mitsui Chemicals and "Takenet (registered trademark) A-3070" manufactured by Mitsui Chemicals). The materials shown below were laminated on the adhesive layer to produce six types of protective sheets for electronic devices. For each of the obtained protective sheets for electronic devices, the clarity was evaluated according to the method described in the aforementioned evaluation method (5). The results are shown in Table 1. It should be noted that clarity 1 to clarity 6 in Table 1 refer to the evaluation of the protective sheets for electronic devices obtained by laminating with the materials 1. to 6. below.

[0269] 1. Lumira (trademark) U403 (made by Toray Industries, thickness 50 μm)

[0270] 2. Cosmoshine SRF (trademark) (manufactured by Toyobo Co., Ltd., thickness 80 μm)

[0271] 3. Triacetyl cellulose (TAC) film (manufactured by Konikami Noruta Co., Ltd., thickness 80 μm)

[0272] 4. OXIS (trademark) PMMA (manufactured by Okura Industries, thickness 40 μm)

[0273] 5. Polycarbonate film PUARE ES (trademark) (manufactured by Teijin Limited, thickness 70 μm)

[0274] 6. ゼオノアフィルム(trademark) (manufactured by Japan ゼオン Co., Ltd., thickness 70μm)

[0275] <Examples 2 to 6, Comparative Examples 3 and 4>

[0276] A multilayer structure and a protective sheet for an electronic device were prepared and evaluated in the same manner as in Example 1, except that the substrate (X) described in Table 1 was used instead of the PET50 used in Example 1. The results are shown in Table 1.

[0277] <Example 7>

[0278] A multilayer structure and a protective sheet for an electronic device were prepared and evaluated in the same manner as in Example 1, except that one side of the PET 50 used in Example 1 was not surface treated, and neither the adhesive layer (AC-1) nor the layer (Y-1) was provided. A multilayer structure was prepared consisting of layer (Y-1) (0.4 μm) / adhesive layer (AC-1) (10 nm) / (surface treated side) substrate (X-1) (50 μm) (non-surface treated side). The results are shown in Table 1.

[0279] <Examples 8-9, Comparative Examples 1 and 2>

[0280] Multilayer structures and electronic device protective sheets were prepared and evaluated in the same manner as in Example 1, except that the time from the completion of application of the coating liquid (S-1) to the start of drying was changed as described in Table 1. The results are shown in Table 1.

[0281]

[0282] Evaluation Method

[0283] (5') Clarity

[0284] When compared with the evaluation results of Example 1 evaluated according to the above-mentioned evaluation method (5), if more evaluators performed A evaluation, it is recorded as "good", if the same, it is recorded as "same", and if fewer evaluators performed A evaluation, it is recorded as "decreased".

[0285] (8) Viscosity

[0286] The viscosity of the coating liquid obtained in the example was measured using a Brookfield rotational viscometer. The measurement conditions are as follows.

[0287] Device: Brookfield Viscometer LVT

[0288] Rotor: No.63

[0289] Speed: 6rpm

[0290] (9) Surface unevenness

[0291] The surface roughness of layer (Y) of the multilayered structures obtained in the Examples and Comparative Examples was evaluated using a scanning white interference microscope. The measurement conditions were as follows. The difference between the highest and lowest points in the measurement range was defined as the surface roughness, and the average value of the 10 points was defined as the surface roughness.

[0292] Device: Hitachi High-Tech Sciences, Ltd., non-contact surface and layer cross-sectional shape measurement system VertScan

[0293] Measuring range: 2.5mm×2.5mm

[0294] <Examples 10 to 13>

[0295] A multilayer structure and a protective sheet for an electronic device were prepared and evaluated in the same manner as in Example 1, except that the stirring time was adjusted so that the viscosity of the coating liquid (S) measured by the method described in the above-mentioned evaluation method (8) would be as shown in Table 2. Furthermore, the surface roughness of layer (Y) of the resulting multilayer structure was measured by the method described in the above-mentioned evaluation method (9). The results are shown in Table 2. Note that clarity was evaluated by the method described in the above-mentioned evaluation method (5').

[0296]

[0297] Evaluation Method

[0298] (10) Contact angle evaluation

[0299] One surface of PET50 was treated with a corona treatment device TEC-4AC manufactured by Kasuga Electric Co., Ltd. at 130 W·min / m 2 Next, place the substrate on the sample stage of the apparatus and drip one drop of coating solution (S) onto the corona-treated surface of PET50 under the following conditions. The water contact angle is measured at 23°C and 50% RH. Repeat this operation 10 times, and the average value is used as the contact angle for evaluation.

[0300] Device: Drop Master DM-500 manufactured by Kyowa Interface Science Co., Ltd.

[0301] Droplet: 2.0 μL

[0302] Waiting time: 2.0 seconds

[0303] (11) Standard deviation of brightness of multilayer structure

[0304] The multilayer structure obtained in the embodiment is cut into a size of 21.0 cm in the TD direction and 29.7 cm in the MD direction. Then, white light is irradiated from one surface of the multilayer structure at an angle of 25° relative to the vertical direction of the multilayer structure using a white light source. After the reflected light is measured at an angle of -30° relative to the vertical direction of the multilayer structure on the same side as the white light source by a line sensor camera, the film is moved at a certain speed in the MD direction. The brightness value within the width (TD direction) of 12 mm at the center point of the MD direction of the measurement range is fitted with a quadratic function by the least squares method. This is used as the baseline, and the baseline correction is performed by calculating the difference between the value obtained by the least squares fitting method and the measured value. The minimum value of the standard deviation of the brightness after baseline correction is used as the standard deviation of the brightness of the multilayer structure. The measurement conditions are as follows.

[0305] <White light source (high-brightness LED lighting)>

[0306] Light source: CCS Corporation LED light source PFBR-150

[0307] Set intensity: 100%

[0308] Line LED lighting width: 60cm

[0309] Distance perpendicular to the multilayer structure: 10 cm

[0310] <Line Sensor Camera>

[0311] Camera: Japan ELECTRO-SENSORY DEVICES Co., Ltd. production line scanning camera NSUF4010S-F (CI)

[0312] Lens: PENTAX YF5028

[0313] Distance perpendicular to the multilayer structure: 15 cm

[0314] <Examples 14 to 17>

[0315] When preparing the coating liquid (S-1) in Example 1, the amount of 18.80 parts by mass of methanol added last was appropriately adjusted, and the water / methanol ratio of the coating liquid (S) was changed to the value shown in Table 3. In addition, coating liquids (S-2) to (S-6) were prepared in the same manner as the coating liquid (S-1) in Example 1, and these were used instead of the coating liquid (S-1). In addition, multilayer structures and protective sheets for electronic devices were prepared in the same manner as in Example 1 for evaluation. In addition, the contact angles of the coating liquids (S-2) to (S-6) were evaluated according to the method described in the above-mentioned evaluation method (10). In addition, the standard deviation of the brightness of the obtained multilayer structure was measured according to the method described in the above-mentioned evaluation method (11). The results are shown in Table 3. It should be noted that the clarity evaluation was evaluated according to the method described in the above-mentioned evaluation method (5').

[0316]

Claims

1. A multilayer structure comprising a substrate (X) and a layer (Y), The layer (Y) comprises a reaction product (D) of a metal oxide (A) containing aluminum atoms and an inorganic phosphorus compound (BI), At least one set of substrates (X) and layer (Y) are adjacent, The a* value of the L*a*b* color system measured in accordance with JIS Z 8722:2009 is -0.8 or more and 0.8 or less, and b ＊ The value is greater than or equal to -0.8 and less than or equal to 0.

8.

2. The multilayer structure according to claim 1, which satisfies the following condition 1: (Condition 1) In the brightness analysis, the multilayer structure is irradiated with light from a white light source and the reflected light observed when the multilayer structure is moved in the MD direction at a constant speed is intermittently measured using a line sensor camera. A white light source is irradiated from one side of the multilayer structure at an angle of 25° relative to the vertical direction of the multilayer structure, and a line sensor camera is used to measure the reflected light at an angle of -30° relative to the vertical direction of the multilayer structure from the same side as the white light source. The obtained brightness was baseline corrected by fitting the brightness values in a range of 12 mm in width (TD direction) at the center point in the MD direction of the measurement range using the least squares method. The minimum value of the standard deviation of the brightness values calculated from the baseline-corrected values was less than 1.

2.

3. The multilayer structure according to claim 1 or 2, wherein The surface irregularities of the layer (Y) measured by white light interferometry were 70 nm or less.

4. The multilayer structure according to any one of claims 1 to 3, wherein the water vapor transmission rate at 40°C and 90% RH measured in accordance with ISO 15106-3:2003 is 1×10 -2 g / m 2 · Days or less.

5. The multilayer structure according to any one of claims 1 to 4, wherein The substrate (X) has a surface layer.

6. The multilayer structure according to any one of claims 1 to 5, wherein It has a structure in which at least one set of a base material (X) and a layer (Y) are directly laminated.

7. The multilayer structure according to any one of claims 1 to 6, wherein The present invention has a structure in which at least one set of a base material (X) and a layer (Y) are laminated via an adhesive layer (I).

8. The multilayer structure according to any one of claims 1 to 7, wherein The substrate (X) includes layers (Y) disposed on both sides thereof.

9. The multilayer structure according to any one of claims 1 to 8, wherein In the infrared absorption spectrum of layer (Y), 800~1400cm -1 The maximum absorption wave number in the region is between 1080 and 1130 cm -1 range.

10. The multilayer structure according to any one of claims 1 to 9, wherein The image clarity of the substrate (X) at a comb width of 0.25 mm measured in accordance with ISO 17221 is 85% or more.

11. The multilayer structure according to any one of claims 1 to 10, wherein a ＊ Value and b ＊ The difference in values (a ＊ value-b ＊ value) is greater than -1.0 and less than 1.

0.

12. A method for producing a multilayer structure, comprising: Step (I) of applying a coating solution (S) comprising a metal oxide (A) containing aluminum atoms, an inorganic phosphorus compound (BI), and a solvent to at least one side of a substrate (X), and heating and drying the coating solution at a temperature of 120° C. or higher to remove the solvent, thereby forming a precursor layer of layer (Y); and step (II) of forming layer (Y) by heat-treating a precursor layer of layer (Y), In step (I), the time from the completion of application of the coating liquid (S) to the start of heating and drying is 1.8 seconds to 9.0 seconds, The L of the obtained multilayer structure measured in accordance with JIS Z 8722:2009 was ＊ a ＊ b ＊ The a* value of the color system is -0.8 or more and 0.8 or less, and b ＊ The value is greater than or equal to -0.8 and less than or equal to 0.

8.

13. The method for producing a multilayer structure according to claim 12, wherein: The coating liquid (S) satisfies the following condition 2; (Condition 2) For the use of corona treatment equipment at 130W·min / m 2 A 2.0 μL drop of the coating liquid (S) was added to the treated surface of the polyethylene terephthalate film at 23° C. and 50% RH, and the contact angle of the drop after 2 seconds was 20° or more and 35° or less.

14. The method for producing a multilayer structure according to claim 13, wherein The coating liquid (S) contains a water / methanol mixed solvent as a solvent, and the water / methanol ratio of the mixed solvent is 3.5 / 6.5 or more and 7 / 3 or less.

15. The method for producing a multilayer structure according to any one of claims 12 to 14, wherein The viscosity of the coating liquid (S) is 400 mPa·s or more and 5000 mPa·s or less, The surface irregularities of the layer (Y) measured by white light interferometry were 70 nm or less. 16 . A protective sheet for an electronic device, comprising the multilayer structure according to claim 1 . 17 . The protective sheet according to claim 16 , which is a protective sheet for protecting the surface of a photoelectric conversion device, an information display device, or a lighting device.

18. An electronic device comprising the protective sheet according to claim 16 or 17.

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