Moisture-barrier laminate film

Abstract

To provide a moisture-barrier laminate film that comprises an inorganic barrier layer and a moisture absorbing layer, and effectively suppresses deactivation of the moisture absorbing layer, and in which excellent barrier property is stably exerted to moisture for a long period of time.SOLUTION: A moisture-barrier laminate film 10 has an inorganic barrier layer 3 and a moisture absorbing layer 5 on a plastic substrate 1, and the inorganic barrier layer 5 is arranged on a high moisture atmosphere side to the moisture absorbing layer 5, where a semi moisture absorbing layer 7 is provided between the inorganic barrier layer 3 and the moisture absorbing layer 5, and solubility coefficients of water in the semi moisture absorbing layer 7 and the moisture absorbing layer 5 satisfy a condition shown in the following formula (1): 0.1S2≤S1<S2 (1). In the formula, S1 denotes a solubility coefficient of water at 85°C in the semi moisture absorbing layer, and S2 denotes a solubility coefficient of water at 85°C in the moisture absorbing layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a moisture barrier laminated film having an inorganic barrier layer and a moisture-absorbing layer. [Background technology]

[0002] As a means of improving the properties of various plastic substrates, particularly their gas barrier properties, it is known that an inorganic barrier layer made of silicon oxide or the like can be formed on the surface of the plastic substrate by vapor deposition (Patent Document 1).

[0003] Furthermore, in recent years, various electronic devices widely used, such as organic electroluminescent displays (OLEDs), solar cells, touch panels, and electronic paper, require high moisture barrier properties for the plastic substrates forming their circuit boards or the films sealing those circuit boards, as charge leakage is undesirable. The formation of the inorganic barrier layer described above cannot meet these high moisture barrier requirements, and therefore, various proposals have been made to improve moisture barrier properties.

[0004] For example, Patent Documents 1 to 3 describe a gas barrier laminate in which a moisture trap layer, in which a specific granular desiccant is dispersed in a matrix of an ionic polymer, is formed on top of an inorganic barrier layer on a plastic substrate.

[0005] Thus, in order to highly enhance moisture barrier properties, various laminates with layer configurations combining an inorganic barrier layer and a moisture-absorbing layer (water-retaining layer) have been proposed. However, in all cases, there is a problem in that the moisture-absorbing layer becomes inactive in a short period of time, and excellent moisture barrier properties are not fully exhibited.

[0006] Furthermore, Patent Document 4 describes a moisture barrier laminate (film) that exhibits excellent moisture barrier properties stably over a long period of time, which has already been proposed and patented by the present applicant.

[0007] The technology described in Patent Document 4 involves forming a thick layer of organic material with excellent moisture diffusion properties, with a thickness of 10 μm or more, between the inorganic barrier layer and the moisture-absorbing layer, which are placed on the high-humidity atmosphere side. This effectively suppresses the deactivation of the moisture-absorbing layer and allows it to exhibit excellent moisture barrier properties over a long period of time. Specifically, the inorganic barrier layer has a considerable number of defects such as cracks formed locally, and moisture flows into the moisture-absorbing layer through these defects, causing it to wear down quickly. However, in the technology described in Patent Document 4, moisture that flows through the defects in the inorganic barrier layer is rapidly diffused by the thick organic layer (10 μm or more), effectively preventing the disadvantage of moisture flowing into the moisture-absorbing layer in a localized area. As a result, the wear of the moisture-absorbing layer is mitigated, and excellent moisture barrier properties are exhibited over a long period of time.

[0008] However, there are limitations to extending the lifespan of moisture barrier properties as described in Patent Document 4, and there is a need to further extend the moisture barrier properties over a longer period of time. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] WO2014 / 123197 [Patent Document 2] Japanese Patent Publication No. 2014-168949 [Patent Document 3] Japanese Patent Publication No. 2014-168950 [Patent Document 4] Patent No. 6657651 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] Therefore, an object of the present invention is to provide a moisture barrier laminated film comprising an inorganic barrier layer and a moisture-absorbing layer, wherein the deactivation of the moisture-absorbing layer is effectively suppressed, and excellent moisture barrier properties are exhibited stably over an even longer period of time. [Means for solving the problem]

[0011] The inventors further advanced the technology of Patent Document 4 and provided a layer (quasi-hygroscopic layer) having a hygroscopic performance comparable to, but not as high as, that of the hygroscopic layer between the inorganic barrier layer and the hygroscopic layer, thereby suppressing the deactivation (consumption) of the hygroscopic layer and enabling the moisture barrier property to be exhibited over a longer period of time.

[0012] According to the present invention, there is provided a moisture barrier laminate having an inorganic barrier layer and a hygroscopic layer on a plastic substrate, wherein the inorganic barrier layer is disposed on the high-moisture atmosphere side with respect to the hygroscopic layer. film In a quasi-hygroscopic layer is provided between the inorganic barrier layer and the hygroscopic layer. The solubility coefficient of water in the hygroscopic layer and the quasi-hygroscopic layer satisfies the following formula (1): 0.1S2 ≦ S1 < S2 (1) In the formula, S1 is the solubility coefficient of water at 85° C. in the quasi-hygroscopic layer, S2 is the solubility coefficient of water at 85° C. in the hygroscopic layer. There is provided a moisture barrier laminate film characterized by satisfying the conditions represented by the above.

[0013] In the moisture barrier laminate film of the present invention, the following embodiments are preferably adopted. (1) S1 is 60% or less of S2. (2) The hygroscopic layer is a layer in which a hygroscopic agent is dispersed in a matrix of a hygroscopic polymer, and the quasi-hygroscopic layer is formed from a resin containing no hygroscopic agent. (3) The hygroscopic agent in the matrix of the hygroscopic polymer is a granular hygroscopic agent. (4) The thickness of the quasi-hygroscopic layer is less than 10 μm. (5) A hydrophobic layer formed of a hydrophobic resin having a solubility coefficient S3 smaller than 0.06S2 (S2 is as described above) is provided between the hygroscopic layer and the quasi-hygroscopic layer. (6) Between the moisture-absorbing layer and the semi-moisture-absorbing layer, or between the inorganic barrier layer and the semi-moisture-absorbing layer, the diffusion coefficient of water D measured at 85°C is 5 × 10 -8 cm 2 A moisture diffusion layer made of resin with a viscosity of / sec or more is provided. (7) The semi-hygroscopic layer is formed of polyamide. (8) The inorganic barrier layer is located on the side of the moisture-absorbing layer that is in a lower moisture atmosphere. [Effects of the Invention]

[0014] The moisture barrier laminated film of the present invention has an inorganic barrier layer and a moisture-absorbing layer, but has a basic structure in which the inorganic barrier layer is positioned on the side of the moisture-absorbing layer that is in a high-moisture atmosphere. That is, when this laminated film is attached to a device such as an organic EL, the inorganic barrier layer is positioned on the side of the moisture-absorbing layer that is in the atmosphere, and therefore the moisture-absorbing layer is located on the inside side of the device relative to the inorganic barrier layer. As a result, moisture permeates from the inorganic barrier layer side toward the moisture-absorbing layer side. Such a basic structure is also employed in the moisture barrier laminate of Patent Document 4, for example.

[0015] The moisture barrier laminated film of the present invention having such a basic structure has the following formula (1): between the inorganic barrier layer and the moisture-absorbing layer. 0.1S2≦S1 <S2 (1) Preferably, S1 ≤ 0. 6S 2 During the ceremony, S1 is the solubility coefficient of water at 85°C in the semi-hygroscopic layer. S2 is the solubility coefficient of water at 85°C in the moisture-absorbing layer. A key feature of this design is the presence of a semi-hygroscopic layer that satisfies the conditions shown. As can be understood from the above-mentioned conditional equation for the solubility coefficient of water, this semi-hygroscopic layer is a layer that exhibits a certain degree of hygroscopicity, though not as much as a hygroscopic layer.

[0016] In other words, because such a semi-hygroscopic layer is provided, the moisture barrier laminated film of the present invention can exhibit the excellent hygroscopic properties of the hygroscopic layer over a long period of time, and its moisture barrier properties can be utilized to the fullest extent. In this invention, such a semi-hygroscopic layer can be formed at extremely low cost, offering significant industrial advantages. Furthermore, its greatest advantage is that, by combining it with other layers, it is possible to further enhance moisture barrier properties while avoiding high costs. [Brief explanation of the drawing]

[0017] [Figure 1] A diagram showing an example of the layer structure of the moisture barrier laminated film of the present invention. [Modes for carrying out the invention]

[0018] <Basic layer structure of the moisture barrier laminated film of the present invention> The moisture barrier laminated film of the present invention is used as a so-called sealing material when attached to a device that is unsuitable for moisture intrusion. Referring to Figure 1, which shows the layer structure of such a laminated film, the laminated film, shown as 10 overall, has an inorganic barrier layer 3 and a moisture-absorbing layer 5 on a plastic substrate 1, and the inorganic barrier layer 3 has a basic structure in which it is located on the high-moisture atmosphere side relative to the moisture-absorbing layer 5. That is, when attached to a device as a sealing material, the inorganic barrier layer 3 is located on the outside (high-moisture atmosphere) side of the device, and the moisture-absorbing layer 5 is located on the inside (low-moisture atmosphere) side of the device.

[0019] In this basic structure, moisture flowing from the high-moisture atmosphere outside the device to the low-moisture atmosphere inside the device is blocked by an inorganic barrier layer 3 provided on the plastic substrate 1, but any moisture that slips through this inorganic barrier layer 3 is captured by the moisture-absorbing layer 5. This basic structure is a conventionally known moisture barrier sex It is also widely used in laminated films.

[0020] However, the moisture-absorbing layer 5 has a limit to the amount of moisture it can absorb, and naturally, after absorbing moisture up to its limit, it loses its ability to trap moisture. In other words, the moisture barrier properties of such a laminated film 10 depend largely on the limit of moisture absorption capacity of the moisture-absorbing layer 5. Therefore, in order to maintain moisture barrier properties over a long period of time, the thickness of the moisture-absorbing layer 5 should be increased. However, increasing the thickness of the moisture-absorbing layer 5 causes a volume change due to swelling of the moisture-absorbing layer 5, and this volume change easily causes delamination, leading to a decrease in moisture barrier properties due to delamination. In addition, the moisture-absorbing layer 5 has a higher manufacturing cost compared to a normal resin layer, so increasing the thickness of the moisture-absorbing layer 5 is also disadvantageous in terms of manufacturing costs.

[0021] However, in the moisture barrier laminated film 10 of the present invention, a semi-moisture-absorbing layer 7 is provided between the inorganic barrier layer 3 and the moisture-absorbing layer 5, that is, on the side of the moisture-absorbing layer 5 that is in a high-moisture atmosphere. As will be described in detail later, this semi-moisture-absorbing layer 7 does not exhibit the same level of moisture absorption as the moisture-absorbing layer 5, but it does exhibit a certain degree of moisture absorption. This makes it possible to extend the time it takes for the moisture absorption of the moisture-absorbing layer 5 to reach its limit moisture content without making the thickness of the moisture-absorbing layer 5 unnecessarily thick, thereby enabling excellent moisture barrier properties to be exhibited over a long period of time.

[0022] Moreover, this semi-moisture-absorbing layer 7 has the advantage of being inexpensive to manufacture, and furthermore, even though its thickness is less than 10 μm, it greatly contributes to extending the lifespan of the moisture barrier properties. For example, compared to increasing the thickness of the moisture-absorbing layer 5 to extend the lifespan of the moisture barrier, providing a semi-moisture-absorbing layer 7 not only prevents delamination but also offers cost advantages. Furthermore, Patent Document 4 describes a technique that prevents the rapid performance degradation of the moisture-absorbing layer 5 by providing an organic layer for moisture diffusion, thereby mitigating localized moisture inflow from defects such as cracks in the inorganic barrier layer 3. In this case, however, the thickness of the organic layer must be 10 μm or more. In contrast, the semi-moisture-absorbing layer 7 does not exhibit a moisture diffusion function but merely absorbs moisture supplementarily, so its thickness can be less than 10 μm. For this reason, it can be combined with various known techniques to improve moisture barrier performance. This point will also be discussed later.

[0023] The above-mentioned semi-moisture-absorbing layer 7 is, if necessary, bonded and fixed to the inorganic barrier layer 3 or moisture-absorbing layer 5 via the adhesive layer 9. The following explains each layer.

[0024] <Plastic base material 1> The plastic substrate 1 serves as the base for the inorganic barrier layer 3, and is typically made of thermoplastic or thermosetting resin, and depending on its form, it is manufactured by injection molding or co-injection molding, extrusion or co-extrusion molding, film or sheet molding, or compression molding. shape, It is molded by casting polymerization or the like. Generally, thermoplastic resins are preferred from the viewpoint of moldability and cost.

[0025] Examples of such thermoplastic resins include the following: Olefin resins: Low-density polyethylene, high-density polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, or α-olefins such as ethylene, propylene, 1-butene, and 4-methyl-1-pentene. samurai Polyolefins such as random or block copolymers, and also cyclic olefin copolymers and cyclic olefin polymers; Ethylene-vinyl compound copolymer: Ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-vinyl chloride copolymer, etc. Styrene resin: Polystyrene, acrylonitrile-styrene copolymer, ABS, α-methylstyrene-styrene copolymer, etc. ; Polyvinyl compounds: Polyvinyl chloride, polyvinylidene chloride, vinyl chloride / vinylidene chloride copolymer, methyl polyacrylate, polymethyl methacrylate, etc. polyamide: Nylon 6, Nylon 6-6, Nylon 6-10, Nylon 11, Nylon 12, etc. Thermoplastic polyester: Polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate (PEN), etc. others: Biodegradable resins such as polycarbonate, polyphenylene oxide, polyimide resin, polyamide-imide resin, polyetherimide resin, fluororesin, allyl resin, polyurethane resin, cellulose resin, polysulfone resin, polyethersulfone resin, ketone resin, amino resin, and polylactic acid; Furthermore, the above-mentioned resins may be blends, or these resins may be modified by copolymerization as appropriate (for example, acid-modified olefin resins).

[0026] Furthermore, this plastic substrate 1 can also be formed from a gas barrier resin with excellent oxygen barrier properties, such as an ethylene-vinyl alcohol copolymer, and may have a multilayer structure including a layer formed from such a gas barrier resin. That is, an inorganic barrier layer 3 can be formed using such a plastic substrate 1 containing a gas barrier resin as a base.

[0027] In this invention, from the viewpoint of ease of availability, cost, moldability, exhibiting some degree of barrier properties against oxygen and moisture, and being suitable as a base for the inorganic barrier layer 3 described later, films of polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate, as well as polyimide resins and cyclic olefin resins such as cyclic olefin copolymers and cyclic olefin polymers, are used on a plastic base. Material 1 It is more preferable to use it as such.

[0028] The thickness of the plastic substrate 1 described above is not particularly limited, but if this thickness is excessively large, the moisture permeability will increase, and the moisture barrier properties mentioned above may decrease. Also, flexibility may be impaired. re This can make handling difficult. Therefore, the thickness of the plastic substrate 1 is usually 200 μm or less, more preferably 125 μm or less, and it is preferable to have a thickness of, for example, 20 μm or more, that ensures an appropriate moisture permeability within this range and also allows for effective formation of the inorganic barrier layer 3.

[0029] <Inorganic barrier layer 3> In the present invention, the inorganic barrier layer 3 located on the high-moisture atmosphere side is an inorganic vapor-deposited film formed by physical vapor deposition such as sputtering, vacuum deposition, and ion plating, or by chemical vapor deposition such as plasma CVD, for example, a film formed from various metals or metal oxides. In particular, it is preferable that the vapor-deposited film be formed by plasma CVD because it can be uniformly formed even on surfaces with irregularities and exhibits excellent barrier properties not only against moisture but also against oxygen and the like. Such an inorganic barrier layer 3 is formed on the aforementioned plastic substrate 1.

[0030] Furthermore, the deposited film (inorganic barrier layer 3) by plasma CVD is obtained by placing a plastic substrate to support the inorganic barrier layer in a plasma processing chamber maintained at a predetermined vacuum level, and supplying a gas (reaction gas) of the metal to be formed or a compound containing the metal and an oxidizing gas (usually oxygen or NOx) together with a carrier gas such as argon or helium, as appropriate, through a gas supply pipe to a plasma processing chamber shielded by a metal wall and reduced to a predetermined vacuum level, and generating a glow discharge using a microwave electric field or a high-frequency electric field in this state, generating plasma with the resulting electrical energy, and depositing the decomposition reaction products of the compound onto the surface of the plastic substrate to form a film. When forming a film using a microwave electric field, the film is formed by irradiating the plasma processing chamber with microwaves using a waveguide or the like. When forming a film using a high-frequency electric field, the plastic substrate is positioned between a pair of electrodes in the plasma processing chamber, and the film is formed by applying a high-frequency electric field to these electrodes.

[0031] Generally, as the reaction gas, it is preferable to use organometallic compounds, such as organoaluminum compounds like trialkylaluminum, organotitanium compounds, organozirconium compounds, or organosilicon compounds, from the viewpoint that they can form a film on the surface of the plastic substrate that has a flexible region containing carbon components and a region on top of it that has a high degree of oxidation and excellent barrier properties. In particular, organosilicon compounds are most preferred because they can form an inorganic barrier layer 3 with high barrier properties against oxygen relatively easily and efficiently.

[0032] Examples of such organosilicon compounds include hexamethyldisilane, vinyltrimethylsilane, methylsilane, dimethylsilane, trimethylsilane, diethylsilane, propylsilane, and phenylsilane. ,Organic silane compounds such as nyltriethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltrimethoxysilane, methyltrimethoxysilane, and methyltriethoxysilane, as well as organic siloxane compounds such as octamethylcyclotetrasiloxane, 1,1,3,3-tetramethyldisiloxane, and hexamethyldisiloxane, are used. In addition to these, aminosilanes and silazanes can also be used. The organometallic compounds described above can be used individually or in combination of two or more.

[0033] When depositing films by plasma CVD using the reaction gases and oxidizing gases of organometallic compounds as described above, it is preferable to lower the glow discharge output (e.g., microwave or high-frequency output), start the film deposition at low power, and then carry out the film deposition by plasma reaction at high power.

[0034] In other words, organic groups (such as CH3 and CH2) contained in the molecules of organometallic compounds normally volatilize as CO2, but at low power levels, some of them do not decompose into CO2 and instead accumulate on the surface of the plastic substrate and are included in the film. On the other hand, as the power level increases, the organic groups decompose into CO2. Therefore, by increasing the power level, it becomes possible to reduce the carbon content in the film and form a film with a high degree of metal oxidation in the organometallic compound. However, while a film with a high degree of metal oxidation has extremely high barrier properties against gases such as oxygen, it has poor flexibility and does not adhere sufficiently to the plastic substrate. In contrast, a film with a low degree of metal oxidation and a high organic component content does not have sufficient barrier properties against gases, but it is highly flexible and exhibits high adhesion to the plastic substrate.

[0035] As can be understood from the above explanation, in the present invention, an organometallic compound is used as the reaction gas, and by performing film deposition at low power in the initial stages of plasma CVD and then increasing the power to perform film deposition, a highly adhesive region containing a large amount of organic components (carbon) is formed in the part that is in contact with the surface of the plastic substrate, and on top of that, a region with a high degree of metal oxidation and high gas barrier properties is formed.

[0036] Therefore, in order to ensure excellent gas barrier properties, the inorganic barrier layer 3 in the present invention preferably includes a high oxidation region where the oxidation degree x of the metal (M) is 1.5 to 2.0 (where x = atomic ratio of O / M). Furthermore, it is preferable that an organic region with a carbon (C) concentration of 20% or more, based on the three elements of metal (M), oxygen (O), and carbon (C), is formed below this high oxidation region (the side in contact with the surface of the plastic substrate). Moreover, silicon (Si) is most preferred as the metal (M).

[0037] Furthermore, it is preferable that the high oxidation region in the inorganic barrier layer 3 constitutes 60% or more of the total thickness of the inorganic barrier layer 3, and the organic region is in contact with the surface of the plastic substrate to a thickness of approximately 5 to 40% of the total thickness of the inorganic barrier layer 3. do It is preferable that it be formed on the side.

[0038] The glow discharge output required when depositing the inorganic barrier layer 3, which has the aforementioned organic and high-oxidation regions, by plasma CVD differs slightly depending on whether microwave or high-frequency discharge is used. For example, with microwave discharge, the organic region is formed at a low output of about 30 to 100 W, while the high-oxidation region is deposited at a high output of 90 W or more. With high-frequency discharge, the organic region is formed at a low output of about 20 to 80 W, while the high-oxidation region is deposited at a high output of 100 W or more. The film deposition time should be set so that the thickness of each region falls within the range mentioned above.

[0039] Furthermore, the overall thickness of the inorganic barrier layer 3 described above varies depending on the application of the moisture barrier laminated film 10 and the required level of barrier performance, but generally, 10 -2 g / m 2 ·day / a tm The following, especially 10 -3 g / m 2 ·day / a tm The thickness should be such that the following water vapor permeability can be ensured. This varies depending on the proportion occupied by the high oxidation region mentioned above, but generally, a thickness of 4 to 500 nm, especially 30 to 400 nm, is sufficient. Furthermore, the inorganic barrier layer 3 described above is commercially available as a gas barrier film in a state where it has been formed on the aforementioned plastic substrate 1.

[0040] <Moisture-absorbing layer 5> The moisture-absorbing layer 5 in the moisture barrier laminated film 10 of the present invention can also be called a moisture trap layer. From the viewpoint of improving barrier performance, for example, the solubility coefficient of water S2 (amount of water dissolved per unit volume) at 85°C is 0.5 to 4.0 g / cm³. 3 • ATM, especially 0.6-3.5 g / cm³ 3 It is preferable that the value is within the range of atm. If this value is too small, the hygroscopicity to trap permeated moisture will be insufficient, and the moisture barrier properties will not be fully exhibited. If the value is too large, swelling due to moisture absorption will easily cause film breakdown or delamination. In other words, due to the presence of such a hygroscopic layer 5, the moisture barrier laminated film 10 of the present invention exhibits excellent moisture barrier properties, and by attaching it to a device in the arrangement shown in Figure 1, it is possible to effectively prevent moisture from entering the inside of the device.

[0041] Such a moisture-absorbing layer 5 is formed by dispersing a desiccant in a resin matrix. In particular, when high barrier properties against moisture are required, it is preferable that the layer is one in which granular adsorbent is dispersed in an ionic polymer, as described in the aforementioned Patent Document 4, from the viewpoint of having excellent moisture-capturing properties and effectively avoiding deformation such as swelling caused by moisture absorption.

[0042] The ionic polymers described above form the matrix of this moisture-absorbing layer 5. There are cationic polymers that have cationic groups (such as NH2 groups) as ionic groups, and anionic polymers that have anionic groups (such as COONa groups and COOH groups) as ionic groups. Generally, granular adsorbents are used that have a lower achievable humidity than ionic polymers.

[0043] In other words, in the moisture-absorbing layer 5, which has the above-mentioned ionic polymer as its matrix, any trace amount of moisture that flows in through the inorganic barrier layer 3 is absorbed by this matrix (ionic polymer). The matrix itself exhibits high hygroscopicity and the high solubility coefficient S2 mentioned above, so it captures and absorbs moisture without any leakage.

[0044] However, if moisture is simply absorbed into the matrix, the absorbed moisture will easily be released due to environmental changes such as a rise in temperature. Furthermore, the intrusion of moisture widens the spacing between the polymer molecules forming the matrix, resulting in swelling of the moisture-absorbing layer 5 and a significant increase in volume. However, if an adsorbent with a lower attainable humidity than the matrix (ionic polymer) is dispersed, the moisture absorbed into the matrix will be further captured by the desiccant, which has a higher hygroscopicity (i.e., a lower attainable humidity) than the matrix. This not only effectively suppresses swelling due to the absorbed water molecules, but also traps these water molecules within the moisture-absorbing layer 5, effectively preventing the release of moisture from the moisture-absorbing layer 5.

[0045] Thus, when a moisture-absorbing layer 5 is formed by dispersing an adsorbent in an ionic polymer, it has a dual function of capturing and trapping moisture, as well as high moisture absorption capacity. Therefore, it can capture moisture even in extremely low humidity environments, capturing it at a speed sufficiently faster than the rate at which moisture permeates the inorganic barrier layer, and further trapping moisture throughout the entire layer. capture This prevents leakage to the outside and achieves remarkably high moisture barrier properties.

[0046] Ionic polymers (cationic polymers); In the present invention, among the ionic polymers used to form the matrix described above, the cationic polymer is a polymer having a cationic group in its molecule that can become positively charged in water, such as a primary to tertiary amino group, a quaternary ammonium group, a pyridyl group, an imidazole group, or a quaternary pyridinium group. Such a cationic polymer has a cationic group that exhibits strong nucleophilic activity and can bond water with hydrogen. capture Therefore, a hygroscopic matrix can be formed. The amount of cationic groups in a cationic polymer should generally be such that the water absorption rate (JIS K-7209-1984) of the formed hygroscopic matrix is ​​20% or more, particularly 30% to 45%, under an atmosphere of 80% RH humidity and 30°C.

[0047] Furthermore, as cationic polymers, those obtained are those obtained by polymerizing or copolymerizing at least one cationic monomer, such as amine monomers like allylamine, ethyleneimine, vinylbenzyltrimethylamine, [4-(4-vinylphenyl)-methyl]trimethylamine, and vinylbenzyltriethylamine; nitrogen-containing heterocyclic monomers like vinylpyridine and vinylimidazole; and their salts, together with other copolymerizable monomers as appropriate, and then partially neutralizing by acid treatment if necessary. Other copolymerizable monomers, though not limited to those listed, include styrene, vinyltoluene, vinylxylene, α-methylstyrene, vinylnaphthalene, α-halogenated styrenes, acrylonitrile, acrolein, methyl vinyl ketone, and vinylbiphenyl.

[0048] Alternatively, instead of using the cationic monomers mentioned above, monomers having functional groups that can be introduced with cationic functional groups, such as styrene, bromobutylstyrene, vinyltoluene, chloromethylstyrene, vinylpyridine, vinylimidazole, α-methylstyrene, and vinylnaphthalene, can be used, and after polymerization, treatments such as amination and alkylation (quaternary ammonium chloride) can be performed to obtain cationic polymers.

[0049] In the present invention, among the cationic polymers mentioned above, allylamine is particularly preferred from the viewpoint of film-forming properties and other factors.

[0050] As described in Patent Document 4, the cationic polymers mentioned above are generally produced by radical polymerization by heating with a polymerization initiator. Furthermore, if polymerization is carried out using monomers that can be introduced with cationic functional groups, cationic group introduction treatments such as amination and alkylation should be performed after polymerization.

[0051] In the present invention, it is preferable to introduce a crosslinked structure into the matrix formed using the cationic polymer described above, in order to ensure mechanical strength without reducing moisture absorption capacity and to improve dimensional stability. In other words, when a cross-linked structure is introduced into a hygroscopic matrix, the molecules of the cationic polymer are constrained by the cross-linking when the matrix absorbs water, suppressing volume changes due to swelling (water absorption) and resulting in improved mechanical strength and dimensional stability. The above crosslinked structure can be introduced by incorporating a crosslinking agent into the coating composition for forming the moisture-absorbing layer 5. Such a crosslinked structure, as described in Patent Document 4, comprises a crosslinkable functional group (e.g., epoxy group) that can react with a cationic group, and a functional group (e.g., alcohol group) that can form a siloxane structure in the crosslinked structure through hydrolysis and dehydration condensation. tree Compounds having a sisilyl group can be used, in particular, the following formula (2): X-SiR1 n (OR 2 ) 3-n (2) In the formula, X is an organic group having an epoxy group at the terminal, R 1 and R 2 are each a methyl group, an ethyl group, or an isopropyl group respectively, n is 0, 1, or 2, and the silane compound represented by the above formula is preferably used. That is, a crosslinked structure can be introduced by blending the above crosslinking agent into the coating composition for forming a moisture-absorbing layer containing the above cationic polymer and then forming a film.

[0052] Ionic polymer (anionic polymer); The anionic polymer used for forming a moisture-absorbing matrix is a polymer having an anionic functional group that can become negatively charged in water, such as a carboxylic acid group, a sulfonic acid group, a phosphonic acid group, or an acidic salt in which these groups are partially neutralized, in the molecule. Since the anionic polymer having such a functional group binds water by hydrogen bonding, capture it can form a moisture-absorbing matrix. The amount of anionic functional groups in the anionic polymer varies depending on the type of the functional group. However, similar to the above-described cationic polymer, the amount is such that the water absorption rate (JIS K-7209-1984) of the formed moisture-absorbing matrix is 20% or more, particularly 30% to 45%, in an atmosphere of 80% RH and 30°C.

[0053] Anionic polymers having the functional groups described above include, for example, carboxylic acid monomers such as methacrylic acid, acrylic acid, and maleic anhydride; sulfonic acid monomers such as α-halogenated vinyl sulfonic acid, styrene sulfonic acid, and vinyl sulfonic acid; phosphonic acid monomers such as vinyl phosphoric acid; and salts of these monomers; at least one of these anionic monomers is polymerized or copolymerized with other copolymerizable monomers as appropriate, and if necessary, partially neutralized by alkali treatment. Other copolymerizable monomers, though not limited to those listed, include styrene, vinyltoluene, vinylxylene, α-methylstyrene, vinylnaphthalene, α-halogenated styrenes, acrylonitrile, acrolein, methyl vinyl ketone, and vinylbiphenyl.

[0054] Alternatively, instead of using the above-mentioned anionic monomers, anionic polymers can be obtained by using esters of the above-mentioned anionic monomers or monomers having functional groups that can introduce anionic functional groups, such as styrene, vinyltoluene, vinylxylene, α-methylstyrene, vinylnaphthalene, and α-halogenated styrenes, and then performing treatments such as hydrolysis, sulfonation, chlorosulfonation, and phosphoniumation after polymerization.

[0055] In the present invention, preferred anionic polymers are poly(meth)acrylic acid and its partially neutralized products (for example, those in which a portion is a sodium salt).

[0056] The anionic polymers described above are generally produced by radical polymerization of monomers having anionic groups by heating with a polymerization initiator. If monomers capable of introducing anionic functional groups are used as monomers, anionic group introduction treatments such as hydrolysis, sulfonation, chlorosulfonation, or phosphoniumization can be performed after polymerization.

[0057] Furthermore, in the present invention, it is particularly preferable to introduce a crosslinked structure into the hygroscopic matrix formed using the aforementioned anionic polymer. This further enhances the moisture trapping capacity of the moisture-absorbing layer 5 and also leads to further improvement in dimensional stability. In other words, in the case of anionic polymers, unlike cationic polymers, water is bonded by hydrogen bonds. capture Therefore, by introducing a network structure (cross-linked structure) with spaces suitable for moisture absorption into the matrix, its hygroscopic properties can be greatly enhanced. Such a cross-linked structure, for example, has hydrophobic parts such as alicyclic structures within the network structure, thereby further enhancing the moisture absorption effect of the hydrophilic parts. Furthermore, by introducing a cross-linked structure into the hygroscopic matrix, when the matrix absorbs water, the anionic polymer molecules are constrained by the cross-linking, suppressing volume changes due to swelling (water absorption) and improving dimensional stability. This effect of improving dimensional stability is the same as that of the cationic polymer described above.

[0058] The above crosslinked structure is introduced by incorporating a crosslinking agent into the coating composition for forming the moisture-absorbing layer 3, similar to the case of cationic polymers. This crosslinking agent is a compound having two or more crosslinkable functional groups (e.g., epoxy groups) that can react with the ionic groups of the anionic polymer, as described in Patent Document 4, for example, formula (3): GO(C=O)-A-(C=O)OG (3) In the formula, G is a glycidyl group, A is a divalent hydrocarbon group having an aliphatic ring, such as a cycloalkylene group. be, This is a diglycidyl ester represented by [formula]. That is, a crosslinked structure can be introduced by incorporating the above crosslinking agent into a moisture-absorbing layer forming coating composition containing the above anionic polymer and performing film formation.

[0059] Desiccant; The desiccant dispersed in the moisture-absorbing layer 5, which has the aforementioned ionic polymer as its matrix (hygroscopic matrix), has a lower achievable humidity than the ionic polymer (cationic or anionic polymer) that forms the matrix, and possesses extremely high moisture absorption performance. By dispersing a desiccant with higher moisture absorption than the matrix in this way, moisture absorbed by the matrix formed by the aforementioned ionic polymer is immediately captured by the desiccant, effectively trapping the absorbed moisture within the matrix. This not only allows the moisture absorption capacity to be effectively exercised even in extremely low humidity environments, but also effectively suppresses swelling of the moisture-absorbing layer 5 due to moisture absorption.

[0060] As a highly hygroscopic desiccant as described above, it is preferable to use one that has a lower achievable humidity than ionic polymers, for example, one that achieves a achievable humidity of 6% or less under environmental conditions of 80% RH humidity and 30°C temperature, as shown in the examples described later. In other words, if the achievable humidity of this desiccant is higher than that of ionic polymers, the trapping of moisture absorbed by the matrix will not be sufficient, and moisture release will easily occur, making it impossible to expect a significant improvement in moisture barrier properties. Furthermore, even if the achievable humidity is lower than that of ionic polymers, if the achievable humidity measured under the above conditions is higher than the above range, for example, moisture trapping in a low-humidity atmosphere may be insufficient, and the moisture barrier properties may not be fully exhibited.

[0061] The above-mentioned desiccants generally have a water absorption rate of 50% or more under an atmosphere of 80% RH humidity and 30°C temperature (JIS K-7209-1984), and are available in inorganic and organic forms. Examples of inorganic desiccants include zeolite, alumina, activated carbon, clay minerals such as montmorillonite, silica gel, calcium oxide, and magnesium sulfate. Examples of organic desiccants include crosslinked anionic polymers or their partially neutralized forms. Examples of these anionic polymers include those obtained by polymerizing or copolymerizing at least one anionic monomer, such as carboxylic acid monomers (e.g., (meth)acrylic acid and maleic anhydride), sulfonic acid monomers (e.g., vinyl sulfonic acid, styrene sulfonic acid, vinyl sulfonic acid), phosphonic acid monomers (e.g., vinyl phosphoric acid), and salts of these monomers, with other monomers. Organic desiccants are particularly effective in applications where transparency is required. For example, fine particles of crosslinked poly(meth)acrylate sodium are a typical organic desiccant.

[0062] In the present invention, granular desiccants with small particle sizes are preferred from the viewpoint of having a large specific surface area and exhibiting high hygroscopicity (for example, with an average primary particle diameter of 100 nm or less, particularly 80 nm or less), and granular desiccants of organic polymers with particularly small particle sizes are optimal. In other words, granular desiccants made of organic polymers have excellent dispersibility within the matrix of ionic polymers, allowing for uniform dispersion. Furthermore, by employing polymerization methods such as emulsion polymerization or suspension polymerization for their manufacture, the particle shape can be made fine and uniformly spherical. By incorporating a certain amount of these particles, it becomes possible to ensure extremely high transparency. Furthermore, fine organic desiccants exhibit remarkably low achievable humidity levels and high hygroscopicity. Moreover, cross-linking minimizes volume changes due to swelling. Therefore, they are ideal for reducing humidity to a completely dry or near-completely dry state while suppressing volume changes. As an example of such organic desiccant microparticles, cross-linked sodium polyacrylate microparticles (average particle size approximately 70 nm) are commercially available from Toyobo Co., Ltd. in the form of a colloidal dispersion (pH=10.4) under the trade name Toughtic HU-820E.

[0063] In the present invention, the amount of the hygroscopic agent described above is set according to the type of ionic polymer, from the viewpoint of fully exhibiting its properties, significantly improving moisture barrier properties, effectively suppressing dimensional changes due to swelling, and ensuring a moisture barrier property higher than that exhibited by the inorganic barrier layer 1 over a long period of time. For example, in a moisture-absorbing layer 5 in which the above-mentioned ionic polymer is used as a matrix and an adsorbent is dispersed in this matrix, if the matrix is ​​formed of a cationic polymer, it is preferable that the adsorbent is present in an amount of 50 parts by weight or more, particularly 100 to 900 parts by weight, per 100 parts by weight of the ionic polymer in the moisture-absorbing layer 5, and more preferably 200 to 600 parts by weight. If the matrix is ​​formed of an anionic polymer, it is preferable that the adsorbent is present in an amount of 50 parts by weight or more, particularly 100 to 1300 parts by weight, per 100 parts by weight of the anionic polymer in the moisture-absorbing layer 5, and more preferably 150 to 1200 parts by weight.

[0064] The thickness of the moisture-absorbing layer 5 described above varies depending on the application of the moisture barrier laminated film 10 and the required level of barrier performance, but 10 -2 g / m 2 ·day / a tm The following, especially 10 -3 g / m 2 ·day / a tm To ensure the following water vapor permeability, a thickness of 1 to 20 μm, particularly 1 to 15 μm, is sufficient. If the thickness is too thin, the amount of absorbed moisture will reach its upper limit in a short period, impairing the moisture barrier properties. Conversely, if the thickness is too thick, the amount of absorbed moisture will increase, but with this increase, the volume change due to swelling will become larger, making delamination more likely.

[0065] <Semi-moisture-absorbing layer 7> In the present invention, the semi-hygroscopic layer 7 is a layer that exhibits a certain degree of hygroscopicity, though not to the same extent as the hygroscopic layer 5, and specifically, the following formula (1): 0.1S2≦S1 <S2 (1) During the ceremony, S1 is the solubility coefficient of water at 85°C in the semi-hygroscopic layer 7. S2 is the solubility coefficient of water at 85°C in the moisture-absorbing layer 5. This layer satisfies the conditions represented by [the formula]. In other words, by providing such a semi-hygroscopic layer 7 between the inorganic barrier layer 3 and the moisture-absorbing layer 5 to perform auxiliary moisture absorption, moisture that has passed through the inorganic barrier layer 3 is temporarily captured by the semi-hygroscopic layer 7, preventing all of such moisture from flowing into the moisture-absorbing layer 5. This prevents the excellent properties of the moisture-absorbing layer 5 from being deactivated, and allows the moisture-absorbing layer 5 to perform at its best over a long period of time.

[0066] Therefore, as shown in equation (1) above, the solubility coefficient S1 in such a quasi-hygroscopic layer 7 should be smaller than the solubility coefficient S2 of the hygroscopic layer 5. However, if it is close to the solubility coefficient S2, then the material used to form the layer is almost the same as that used for the hygroscopic layer 5. to This would negate the benefits of providing the semi-hygroscopic layer 7 (such as swelling suppression and cost reduction). Therefore, it is preferable that the solubility coefficient S1 of the semi-hygroscopic layer 7 be 60% or less of the solubility coefficient S2. Furthermore, if the solubility coefficient S1 is lower than 10% of the solubility coefficient S2 (S1 < 0.1S2), the hygroscopicity is too low, and the function of extending the hygroscopic lifespan of the hygroscopic layer 5 becomes unsatisfactory.

[0067] In the present invention, the semi-hygroscopic layer 7 that satisfies the above conditions is formed, for example, from a resin that satisfies the conditions of formula (1) without the addition of a desiccant. Such a semi-hygroscopic layer 7 is formed by adding a desiccant. hand Because it is absent, it can be formed at a lower cost than moisture-absorbing layer 5.

[0068] Examples of resins that satisfy the conditions of formula (1) used to form the semi-hygroscopic layer 7 include ionic polymers with a lower concentration of cationic or anionic groups compared to the ionic polymer used to form the hygroscopic layer 5. In particular, polyamides, ethylene-vinyl alcohol copolymers, amino resins, and polylactic acid are preferred because they are less expensive than ionic polymers, with polyamide being the most preferred. Such polyamides can also be used as the plastic substrate 1 that forms the base for the inorganic barrier layer 3 mentioned above. Typical examples include nylon 6, nylon 6-6, nylon 6-10, nylon 11, and nylon 12.

[0069] The thickness of the aforementioned semi-moisture-absorbing layer 7 should be less than 10 μm, preferably in the range of 2 to 8 μm. If this thickness is excessively large, the volume change due to swelling together with the moisture-absorbing layer 5 will be large, making delamination more likely. Conversely, if this thickness is too small, it will be difficult to extend the lifespan of the moisture-absorbing layer 5 through supplemental moisture absorption.

[0070] <Other resin layers> In the present invention, a layer other than the semi-moisture-absorbing layer 7 can be provided between the inorganic barrier layer 3 and the moisture-absorbing layer 5. For example, in the example shown in Figure 1, a semi-hygroscopic layer 7 and a hygroscopic layer 5 are continuously provided on the inorganic barrier layer 3. However, an adhesive layer 9 can also be provided to firmly fix the semi-hygroscopic layer 7 to the inorganic barrier layer 3 and the hygroscopic layer 5. Such an adhesive layer 9 is quite thin, for example, having a thickness of about 1 to 6 μm.

[0071] Suitable adhesives for forming the adhesive layer 9 described above include epoxy adhesives and urethane adhesives, which are known as dry laminating adhesives.

[0072] Epoxy adhesives; The epoxy adhesives described above bond by curing a liquid epoxy resin with an epoxy hardener. Such epoxy resins are liquid resins having epoxy groups in their molecules, and react with epichlorohydrin with phenol compounds, amine compounds, carboxylic acids, etc. twist Typical examples of the resulting compounds include those obtained by oxidizing unsaturated compounds such as butadiene with organic peroxides, and any type can be used.

[0073] Specific examples of epoxy adhesives, though not limited to these, include bisphenol A or bisphenol F epoxy resins, novolac epoxy resins, cyclic aliphatic epoxy resins, long-chain aliphatic epoxy resins, glycidyl ester epoxy resins, and glycidylamine epoxy resins. In the present invention, glycidylamine-type epoxy resins are particularly preferred because they can form an adhesive layer with a high elastic modulus.

[0074] Furthermore, while known epoxy curing agents such as amines, acid anhydrides, and polyamides can be used, amine-based curing agents, particularly aromatic polyamines represented by metaphenylenediamine, are preferred from the viewpoint of forming a coating film (adhesive layer) with a high elastic modulus that can easily follow thermal shrinkage.

[0075] The ratio of epoxy resin to hardener should be set according to the epoxy equivalent content of the epoxy resin so that a sufficient cured film is formed.

[0076] Urethane-based adhesive; Urethane adhesives consist of a reaction product of isocyanate and (meth)acrylic compounds or polyester polyols. These adhesives typically contain known curing catalysts such as amine-based catalysts, metal catalysts, or phosphate-modified compounds. The amount of curing catalyst is such that a dense cured film (adhesion) is formed at a temperature and time that does not cause thermal deformation of the substrate resin. Agent The type of curing catalyst is set so that a layer can be formed.

[0077] Polyols used in the formation of polyurethane adhesives are compounds that have two or more OH groups in a single molecule, and the following compounds are typical examples. Di-, tri-, tetra-, penta-, hexa-hydroxy compounds; Polyesters (polyester polyols) containing two or more OH groups in one molecule; Polyethers (polyether polyols) containing two or more OH groups in one molecule; Polycarbonates containing two or more OH groups in one molecule (polycarbonate polyols); Polycaprolactone (polycaprolactone polyol) containing two or more OH groups in one molecule; Acrylic polymers (polyacrylic polyols) containing two or more OH groups in one molecule; The most suitable polyol in the present invention is a polyester polyol.

[0078] The polyester polyols described above are polymers obtained by the condensation reaction of polyols with polybasic acids such as adipic acid and phthalic acid. Examples of polyols that react with polybasic acids include aliphatic polyols such as ethylene glycol, propylene glycol, neopentyl glycol, and pentaerythritol; aromatic alcohols such as dihydroxynaphthalene, trihydroxynaphthalene, and bisphenol A; and sulfur-containing polyols such as bis-[4-(hydroxyethoxy)phenyl] sulfide.

[0079] Furthermore, the polyisocyanates that react with the polyols are compounds that have two or more NCO groups in a single molecule. Specific examples, though not limited to these, include the following compounds. Aliphatic isocyanates such as ethylene diisocyanate, trimethylene diisocyanate, and tetramethylene diisocyanate; Alicyclic isocyanates such as isophorone diisocyanate, norbornane diisocyanate, bis(isocyanate methyl)cyclohexane, and 2-isocyanate methyl-3-(3-isocyanate propyl)-5-isocyanate methyl-bicyclo[2,2,1]-heptane; Aromatic isocyanates such as xylylene diisocyanate, bis(isocyanate ethyl)benzene, bis(isocyanate methyl)naphthalene, and bis(isocyanate methyl)diphenyl ether; Sulfur-containing aliphatic isocyanates such as thiodiethyl diisocyanate; Aliphatic sulfide isocyanates such as bis[2-(isocyanatemethylthio)ethyl]sulfide; Aromatic sulfide isocyanates such as diphenyl sulfide-2,4'-diisocyanate; Aromatic disulfide isocyanates such as diphenyl disulfide-4,4'-diisocyanate; Aromatic sulfone isocyanates such as diphenylsulfone-4,4'-diisocyanate; Sulfonic acid ester isocyanates such as 4-methyl-3-isocyanate-benzenesulfonyl-4'-isocyanate-phenol ester; Aromatic sulfonic acid amide isocyanates such as 4-methyl-3-isocyanate-benzenesulfonylanilide-3'-methyl-4'-isocyanate; Sulfur-containing heterocyclic isocyanates such as thiophene-2,5-diisocyanate;

[0080] The polyisocyanates mentioned above are typically used in amounts such that there are approximately 0.8 to 1.2 moles of isocyanate groups (NCO groups) per mole of hydroxyl groups present in the aforementioned polyol.

[0081] The epoxy adhesive and urethane adhesive described above are applied to a designated area (for example, the surface of the inorganic barrier layer 3 or the moisture-absorbing layer 5) using a volatile organic solvent such as hydrocarbon, alcohol, ketone, ester, or ether, and dried to form an adhesive layer 9. The adhesive layer 9 thus formed is usually cured by being held at a temperature of about 30 to 50°C for 24 hours or more.

[0082] Furthermore, in the present invention, wet layer Since layer 7 can be thinner than 10 μm, a layer can be provided to improve moisture barrier properties. wet layer Because 7 can be thin, it avoids the overall thickness of film 10 becoming unnecessarily thick.

[0083] For example, a hydrophobic layer made of a hydrophobic resin with a solubility coefficient S3 smaller than 0.06S2 (where S2 is as described above) can be provided between the moisture-absorbing layer 5 and the semi-moisture-absorbing layer 7. Since such a hydrophobic layer has the function of blocking moisture, similar to the inorganic barrier layer 3, it can prevent excessive moisture from flowing into the moisture-absorbing layer 5 and suppress the wear of the moisture-absorbing layer 5. Examples of such hydrophobic layers, though not limited to these, include olefin resins and polyester resins (such as polyethylene terephthalate), which can also be used as plastic substrates. Furthermore, the epoxy adhesives mentioned earlier also function as hydrophobic resins. Such a hydrophobic layer only needs to have a thickness of about 1 to 4 μm.

[0084] Furthermore, if the thickness of the moisture barrier laminated film 10 can be increased, then the diffusion coefficient of water D measured at 85°C is 5 × 10 between the moisture-absorbing layer 5 and the semi-moisture-absorbing layer 7, or between the inorganic barrier layer 3 and the semi-moisture-absorbing layer 7. -8 cm 2 A moisture diffusion layer formed from a resin with a diffusion coefficient of 1 / sec or higher (moisture-diffusing resin) can also be provided. This diffusion coefficient D is measured by the method described in the examples below. In other words, such a moisture diffusion layer diffuses moisture that has passed through defects such as cracks in the inorganic barrier layer 3, preventing moisture from concentrating locally and flowing into the moisture-absorbing layer 5, thereby suppressing partial wear of the moisture-absorbing layer 5. Suitable moisture-diffusing resins include, for example, olefin resins. While these olefin resins can also be used to form the hydrophobic layer described above, when functioning as a moisture diffusion layer, a thickness of 10 μm or more, particularly 20 μm or more, is required, and most preferably, the thickness should be three times or more that of the moisture-absorbing layer 5.

[0085] In the present invention, when forming the hydrophobic layer or moisture diffusion layer described above, the epoxy adhesive or urethane adhesive described above can be used as needed.

[0086] Furthermore, in the example shown in Figure 1, the inorganic barrier layer 3 is provided on the high-moisture atmosphere side, but such an inorganic barrier layer 3 can also be provided on the low-moisture atmosphere side. That is, a structure can be formed in which a semi-moisture-absorbing layer 7, a moisture-absorbing layer 5, and other layers as needed are placed between a pair of inorganic barrier layers 3, 3. In such a layer structure, when the amount of moisture absorbed by the moisture-absorbing layer 5 exceeds the upper limit, and moisture permeates without being trapped by the moisture-absorbing layer 5, such moisture can be blocked by the inorganic barrier layer 3 on the low-moisture atmosphere side.

[0087] <Application> The moisture barrier laminated film of the present invention, by forming a semi-hygroscopic layer 7, can maintain the excellent moisture trapping capacity of the moisture-absorbing layer 5 over a long period of time, and is also advantageous in terms of cost. Moreover, since this semi-moisture-absorbing layer 7 can be extremely thin, various known layer structures can be used in combination, thereby achieving a water vapor transmission rate of 10 without making the film extremely thick. -5 g / m 2 This enables the achievement of an ultra-high barrier against moisture, with a moisture resistance of less than / day.

[0088] Such a moisture barrier laminated film 10 of the present invention can be suitably used as a film for sealing various electronic devices, such as organic EL elements, solar cells, electronic paper, and other electronic circuits. [Examples]

[0089] The excellent performance of the moisture barrier laminated film 10 of the present invention is demonstrated in the following practical applications. Execution Let me explain with an example.

[0090] <Measurement of water's solubility coefficient S and diffusion coefficient D> Using a high-sensitivity water vapor transmission rate analyzer (Delta Palm, manufactured by Technolox), evaluation samples were placed in the measurement cell, and pressure equivalent to 85°C and 85% RH of water vapor was created on both sides of the sample. The water vapor transmission rate was measured, and the delay time (Δt) to reach a steady state was calculated. The solubility coefficient S and diffusion coefficient D of water for each sample were calculated from the following equations (1) and (2). In the following equations, Sa is the thickness of the sample. Diffusion coefficient D = (Sa) 2 / (6×Δt) (1) Solubility coefficient S = Water vapor transmission rate / Diffusion coefficient D (2)

[0091] <Moisture permeability (g / m 2 Measurement of / day> Using a high-sensitivity water vapor transmission rate measuring device (DeltaPalm, manufactured by Technolox), moisture barrier lamination was measured. film The semi-moisture-absorbing layer 7 is positioned on the higher moisture atmosphere side than the moisture-absorbing layer 5 in the measurement cell, and the pressure due to water vapor equivalent to 85°C and 85% RH is applied to the moisture barrier layer. film The mixture was formed on both sides, and the water vapor transmission rate was measured.

[0092] <Duration of trap performance> In the above evaluation, the time it took for the trap performance to become inactive was assessed. 8 The following criteria were used for evaluation under an atmospheric environment of 5℃ and 85% humidity. × The time it takes for the trap layer to become inactive and the barrier performance to deteriorate by an order of magnitude from the initial state is less than 50 hours. ○: The above time is 50 hours or more. ◎: The above time is 200 hours or more.

[0093] <Evaluation of delamination after moisture absorption> Moisture barrier sex Lamination film After storing the material in an 85°C, 85% humidity environment for 200 hours to allow it to absorb moisture, the adhesion between the moisture-absorbing layer 5 and the semi-moisture-absorbing layer 7 or the inorganic barrier layer 3 was confirmed by a T-type peel test. The evaluation criteria are as follows: ○: Maintains more than 50% of the initial adhesion before moisture absorption. △: Initial adhesion fell below 50%. × Initial adhesion fell to less than 50%, and furthermore, the moisture-absorbing layer underwent cohesive failure.

[0094] <Fabrication of polyethylene terephthalate (PET) film coated with an inorganic barrier layer> An inorganic barrier layer 3 of silicon dioxide was formed on one side of a 100 μm thick biaxially oriented PET film using a plasma CVD apparatus. The film formation conditions are shown below. A CVD system was used that included a high-frequency output power supply with a frequency of 27.12 MHz and a maximum output of 2 kW, a matching box, a metal cylindrical plasma processing chamber with a diameter of 300 mm and a height of 450 mm, and an oil-sealed rotary vacuum pump for evacuating the processing chamber. A plastic substrate was placed on a parallel flat plate in the processing chamber, 3 sccm of hexamethyldisiloxane and 45 sccm of oxygen were introduced, and then a high-frequency oscillator was used to generate high-frequency waves at an output of 50 W, allowing for film formation for 2 seconds to create an adhesion layer. Next, a high-frequency oscillator was used to generate a high frequency at an output of 200W, and a film was formed for 100 seconds to create an inorganic barrier layer 3 of silicon dioxide, thereby obtaining an inorganic barrier layer coated PET film A1. The water vapor transmission rate of the obtained inorganic barrier layer coated PET film A1, measured at 40°C and 90%RH, was 1 × 10⁻⁶. -2 g / m 2 It was / day.

[0095] <Preparation of hygroscopic coating liquid A Made > Polyallylamine (manufactured by Nitto Boseki Medical Co., Ltd., PAA-15C, aqueous solution, solids content 15%) was used as an ionic polymer and diluted with water to obtain a polymer solution with a solids content of 4% by weight. On the other hand, γ-glycidoxypropyltrimethoxysilane was used as a crosslinking agent and dissolved in water to a concentration of 4% by weight to prepare a crosslinking agent solution. Next, the polymer solution and the crosslinking agent solution were mixed so that γ-glycidoxypropyltrimethoxysilane was present in an amount of 15 parts by weight per 100 parts by weight of polyallylamine to prepare a hygroscopic coating solution A.

[0096] Preparation of hygroscopic coating liquid B Made > Polyallylamine (manufactured by Nitto Boseki Medical Co., Ltd., PAA-15C, aqueous solution, solids content 15%) was used as an ionic polymer and diluted with water to obtain a polymer solution with a solids content of 5% by weight. On the other hand, γ-glycidoxypropyltrimethoxysilane was used as a crosslinking agent and dissolved in water to a concentration of 5% by weight to prepare a crosslinking agent solution. Next, the polymer solution and the crosslinking agent solution were mixed so that γ-glycidoxypropyltrimethoxysilane was present in an amount of 15 parts by weight per 100 parts by weight of polyallylamine. Then, to this mixed solution, crosslinked sodium polyacrylate (Toyobo Co., Ltd., Toughtic HU-820E, water dispersion, solids content 13%) was added as a hygroscopic agent in an amount of 400 parts by weight relative to the polyallylamine. The mixture was then adjusted with water to a solids content of 5% and thoroughly stirred to prepare a hygroscopic coating solution B.

[0097] <Example 1> The hygroscopic coating liquid A obtained above was applied to the side of the inorganic barrier film A1 on which the inorganic barrier layer 3 was formed, using a bar coater. The coated film was then heat-treated in a box-type electric oven under conditions of a peak temperature of 120°C and a peak temperature holding time of 6 seconds to form a semi-hygroscopic layer 7 with a thickness of 1 μm, thereby obtaining the coated film B1. Next, the hygroscopic coating liquid B obtained above was applied onto the semi-hygroscopic layer 7 using a bar coater. The coated film was then heat-treated in a box-type electric oven under conditions of a peak temperature of 120°C and a peak temperature holding time of 10 seconds to obtain a coated film B2 with a hygroscopic layer 5 having a thickness of 3 μm.

[0098] Next, in a glove box adjusted to a nitrogen concentration of 99.95% or higher, the surface of the inorganic barrier layer-coated PET film A1, on which the inorganic barrier layer 3 is formed, is dry-laminated to the surface of the coating film B2 on which the moisture-absorbing layer 5 is formed, via a 1.8 μm thick urethane-based adhesive, thereby creating a moisture barrier laminate. film I got 1.

[0099] <Example 2> In Example 1, instead of the hygroscopic coating liquid B used to form the semi-hygroscopic layer 7, a main polymer solution (Mitsui Chemicals "wpb-341", 30% solids) containing water-dispersible urethane resin particles (Mw=1,000,000, glass transition temperature=68°C, average particle size 55 nm) was used, and a coating liquid C was prepared by adding a blocked isocyanate (Mitsui Chemicals "XWB-F206MEDG") as a curing agent to this main polymer solution so that the curing agent solids amounted to 10 parts by weight per 100 parts by weight of main solids, and then diluting it with a mixed solvent of water and 2-propanol to obtain a coating liquid C with a solids content of 15%. A semi-hygroscopic layer 7 with a thickness of 3 μm was formed using the same method as in Example 1. film I got 2.

[0100] <Example 3> In Example 2, a moisture barrier laminate is formed in the same manner as in Example 2, except that a moisture-absorbing coating liquid B is used instead of moisture-absorbing coating liquid A to form the moisture-absorbing layer 5, with a thickness of 3 μm. film I got 3.

[0101] <Example 4> In Example 1, a moisture barrier laminate is formed in the same manner as in Example 1, except that instead of the hygroscopic coating liquid B used to form the semi-hygroscopic layer 7, a 25 μm hygroscopic polyamide film is laminated with the above-mentioned urethane adhesive with a thickness of 1.8 μm to form the semi-hygroscopic layer 7. film I got 4.

[0102] <Example 5> In Example 2, a coating solution D was used on the semi-hygroscopic layer 7. This solution was prepared by adding polyisocyanate (Mitsui Chemicals "D-110N") as a curing agent to a main polymer solution containing an acrylic resin (Arakawa Chemical Industries, Ltd. "Aracoat DA-105", 30% solids) in an amount of 30 parts by weight per 100 parts by weight of the main polymer solution's solids, and then diluting it with methyl ethyl ketone to obtain a coating solution D with a solids content of 20%. A hydrophobic coating solution with a thickness of 1 μm was then applied. layers Moisture barrier laminate is formed in the same manner as in Example 1, except for the formation process. film I got a 5.

[0103] <Example 6> In Example 2, a 12 μm biaxially oriented PET film was laminated between the inorganic barrier layer 3 and the semi-moisture-absorbing layer 7 with the above urethane adhesive with a thickness of 1.8 μm to facilitate moisture diffusion. layers Moisture barrier laminate is formed in the same manner as in Example 1, except for the formation process. film I got a 6.

[0104] <Comparative Example 1> In Example 1, moisture barrier lamination is performed in the same manner as in Example 1, except that the hygroscopic coating liquid A is applied to the side of the inorganic barrier film A1 on which the inorganic barrier layer 3 is formed, using a bar coater, without forming a semi-hygroscopic layer 7. film I got a 7.

[0105] <Comparative Example 2> In Example 6, without forming a semi-hygroscopic layer 7, the hygroscopic coating liquid A was coated by a bar coater, and the above moisture diffusion occurred. Layer Moisture barrier lamination is performed in the same manner as in Example 6, except for the coating process. Film 8 I obtained it.

[0106] <Comparative Example 3> In Example 1, a moisture barrier laminate was formed in the same manner as in Example 6, except that coating liquid D was used instead of hygroscopic coating liquid B to form the semi-hygroscopic layer 7, and a semi-hygroscopic layer 7 with a thickness of 3 μm was formed. Film 9 I obtained it.

[0107] <Evaluation Test> The moisture barrier laminated film prepared as described above was measured for various properties using the method described above, and the results are shown in Table 1.

[0108] [Table 1] [Explanation of Symbols]

[0109] 1: Plastic base material 3: Inorganic barrier layer 5: Moisture-absorbing layer 7: Semi-moisture-absorbing layer 9: Adhesive layer 10: Moisture barrier laminated film

Claims

1. In a moisture barrier laminated film having an inorganic barrier layer and a moisture-absorbing layer on a plastic substrate, wherein the inorganic barrier layer is positioned on the side of the moisture-absorbing layer that is in a high-moisture atmosphere, A semi-moisture-absorbing layer is provided between the inorganic barrier layer and the moisture-absorbing layer. The solubility coefficients of water in the aforementioned moisture-absorbing layer and semi-moisture-absorbing layer are given by the following formula (1): 0.1S2≦S1<S2 (1) During the ceremony, S1 is the solubility coefficient of water at 85°C in the semi-hygroscopic layer. S2 is the solubility coefficient of water at 85°C in the moisture-absorbing layer. A moisture barrier laminated film characterized by satisfying the conditions shown.

2. The moisture barrier laminated film according to claim 1, wherein S1 is 60% or less of S2.

3. The moisture-absorbing layer is a layer in which a desiccant is dispersed in a matrix of a hygroscopic polymer, and the semi-hygroscopic layer is formed from a resin that does not contain a desiccant, as described in claim 1.

4. The moisture barrier laminated film according to claim 3, wherein the desiccant in the matrix of the hygroscopic polymer is a granular desiccant.

5. The moisture barrier laminated film according to claim 1, wherein the thickness of the semi-moisture-absorbing layer is less than 10 μm.

6. The moisture barrier laminated film according to claim 1, wherein a hydrophobic layer is provided between the moisture-absorbing layer and the semi-moisture-absorbing layer, the hydrophobic layer being made of a hydrophobic resin having a solubility coefficient S3 less than 0.06S2 (where S2 is as described above).

7. Between the moisture-absorbing layer and the semi-moisture-absorbing layer, or between the inorganic barrier layer and the semi-moisture-absorbing layer, the diffusion coefficient of water D measured at 85°C is 5 × 10 －８ cm ２ A moisture barrier laminated film according to claim 1, which is provided with a moisture diffusion layer formed from a resin of / sec or more.

8. The moisture barrier laminated film according to claim 1, wherein the semi-moisture-absorbing layer is made of polyamide.

9. The moisture barrier laminated film according to claim 1, having an inorganic barrier layer on the side of the moisture-absorbing layer that is in a lower moisture atmosphere.

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