Moisture and oxygen barrier laminate with improved durability

Abstract

The present invention relates to a moisture and oxygen barrier laminate having improved durability. Provided according to the present invention is a laminate comprising a primer layer and an inorganic barrier layer, which are sequentially formed on one surface of a transparent substrate, wherein the primer layer comprises a polyurethane resin having a glass transition temperature (Tg) of 0℃ to 20℃. The laminate according to the present invention can maintain excellent interlayer adhesion even when an external factor, such as heating or bending, is applied thereto, and thus can exhibit excellent moisture and oxygen barrier properties.

Description

Moisture and oxygen barrier laminate with improved durability

[0001] The present invention relates to a moisture and oxygen barrier laminate having improved durability.

[0002]

[0003] Barrier laminates formed by forming an inorganic thin film such as aluminum oxide on the surface of a plastic substrate are used for packaging various items such as food and electronic devices.

[0004] However, these barrier laminates have a problem in that their barrier properties deteriorate due to separation or breakage between layers when subjected to external factors such as heating or bending.

[0005] Accordingly, various studies have been attempted to improve the durability and flexibility of barrier laminates. For example, polymer coating layers of various compositions are laminated between the constituent layers of the barrier laminate.

[0006] However, existing barrier laminates still have a problem in that the adhesion between the organic layer and the inorganic layer is still insufficient, resulting in separation between layers during handling.

[0007]

[0008] The present invention provides a moisture and oxygen barrier laminate having improved durability.

[0009]

[0010] Hereinafter, a moisture and oxygen barrier laminate according to an embodiment of the present invention will be described.

[0011]

[0012] Unless otherwise defined herein, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing specific embodiments only and is not intended to be limiting.

[0013] As used herein, the singular forms also include the plural forms unless the context clearly dictates otherwise.

[0014] As used herein, the term “including” means specifying a particular characteristic, region, integer, step, operation, element and / or component, but does not exclude the presence or addition of other particular characteristics, regions, integers, steps, operations, elements, components and / or groups.

[0015] The present invention is susceptible to various modifications and takes various forms. Specific embodiments are illustrated and described in detail below. However, this is not intended to limit the present invention to specific disclosed forms, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

[0016] In this specification, when the positional relationship between two parts is described as, for example, ‘on top of’, ‘upper part of’, ‘lower part of’, ‘next to’, etc., one or more other parts may be located between the two parts unless the expression ‘right’ or ‘directly’ is used.

[0017] In this specification, when a temporal relationship is described as, for example, ‘after’, ‘following’, ‘next to’, or ‘before’, it may also include cases where it is not continuous, unless the expression ‘immediately’ or ‘directly’ is used.

[0018] The term 'at least one' in this specification should be understood to include all possible combinations of one or more associated items.

[0019]

[0020] According to one embodiment of the invention,

[0021] It comprises a primer layer and an inorganic barrier layer sequentially formed on one side of a transparent substrate,

[0022] The above primer layer has a glass transition temperature (T) of 0°C to 20°C. g ), including a polyurethane resin having

[0023] A laminate is provided.

[0024]

[0025] As a result of the continuous research of the present inventors, it was confirmed that in a laminate satisfying the above characteristics, a strong adhesive force can be secured between an organic layer including the transparent substrate and an inorganic layer including the inorganic barrier layer, thereby providing a moisture and oxygen barrier laminate having improved durability.

[0026] The primer layer including the polyurethane resin improves the barrier properties and interlayer adhesion of the laminate, thereby enabling the laminate to exhibit improved durability.

[0027]

[0028] According to one embodiment of the invention, the laminate may have a structure including a primer layer and an inorganic barrier layer sequentially formed on one surface of a transparent substrate.

[0029] According to another embodiment of the invention, the laminate may have a structure including a primer layer and an inorganic barrier layer sequentially formed on each side of the transparent substrate.

[0030]

[0031] The above transparent substrate may be a plastic film having transparency and flexibility.

[0032] Specifically, the transparent substrate may be a plastic film comprising at least one polymer selected from the group consisting of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), cycloolefin polymer (COP), cycloolefin copolymer (COC), polycarbonate (PC), and poly(methyl methacrylate) (PMMA). Among these, a polyethylene terephthalate film has excellent strength while combining transparency and flexibility, and thus can be suitably applied as the transparent substrate.

[0033]

[0034] According to one embodiment of the invention, the transparent substrate may have a thickness of 5 μm to 300 μm.

[0035] To ensure that the substrate exhibits adequate strength, the thickness of the transparent substrate is preferably 5 μm or greater. However, if the substrate is too thick, flexibility may be reduced. Therefore, the thickness of the transparent substrate is preferably 300 μm or less.

[0036] More preferably, the thickness of the transparent substrate may be 5 μm to 250 μm, or 10 μm to 250 μm, or 10 μm to 200 μm, or 10 μm to 150 μm, or 10 μm to 100 μm.

[0037]

[0038] If necessary, the transparent substrate may be surface-treated to improve its surface wettability or adhesion to the inorganic barrier layer. Non-limiting examples of the surface treatment include plasma treatment, corona treatment, glow discharge treatment, and the like.

[0039]

[0040] The above primer layer ensures strong adhesion between the organic layer including the transparent substrate and the inorganic layer including the inorganic barrier layer.

[0041] According to one embodiment of the invention, the primer layer has a glass transition temperature (T) of 0°C to 20°C. g ) includes a polyurethane resin.

[0042] If the glass transition temperature of the polyurethane resin included in the primer layer is too low, blocking may occur during the manufacturing process of the laminate, which may reduce productivity. Therefore, it is preferable that the polyurethane resin have a glass transition temperature of 0°C or higher.

[0043] In addition, if the glass transition temperature of the polyurethane resin included in the primer layer is outside the above range, the adhesive strength between the constituent layers and the barrier properties of the laminate may rather deteriorate.

[0044] In addition, if the glass transition temperature of the polyurethane resin is too high, the anchoring effect in which inorganic particles are embedded and fixed on the primer layer during the process of forming the inorganic barrier layer on the primer layer may not be sufficiently exhibited.

[0045] Preferably, the primer layer may include a polyurethane resin having a glass transition temperature of 0°C or higher, and 20°C or lower, or 15°C or lower, or 10°C or lower. Specifically, it is preferable that the primer layer include a polyurethane resin having a glass transition temperature of 0°C to 20°C, or 0°C to 15°C, or 0°C to 10°C.

[0046]

[0047] The above polyurethane resin includes a hard segment having a unit formed by combining diisocyanate and diol and a soft segment having a polyether or polyester unit.

[0048] The above hard segment refers to a repeating unit with relatively low chain flexibility among the repeating units of the polyurethane resin, and includes a unit formed by the combination of a diol with a short alkyl chain and a diisocyanate.

[0049] The above soft segment refers to a repeating unit with relatively high chain flexibility among the repeating units of the polyurethane resin, and includes a unit formed by combining a long alkyl chain diol or polyol and diisocyanate.

[0050]

[0051] According to one embodiment of the invention, it is preferable that the polyurethane resin comprises 30 wt% to 80 wt% of a hard segment having a unit formed by combining diisocyanate and diol, and 20 wt% to 70 wt% of a soft segment having a polyether or polyester unit.

[0052] In order to realize the durability improvement effect due to the introduction of the above primer layer, it is preferable that the soft segment contained in the polyurethane resin is 20 wt% or more or 25 wt% or more. However, if the content of the soft segment contained in the polyurethane resin is too high, the stiff crystalline region may increase, causing the glass transition temperature of the polyurethane resin to exceed the upper limit of the above preferable range. Therefore, it is preferable that the soft segment contained in the polyurethane resin is 70 wt% or less or 65 wt% or less.

[0053] Preferably, the polyurethane resin may comprise 30 wt% to 75 wt% of the hard segment and 25 wt% to 70 wt% of the soft segment. More preferably, the polyurethane resin may comprise 35 wt% to 75 wt% of the hard segment and 25 wt% to 65 wt% of the soft segment.

[0054]

[0055] According to one embodiment of the invention, in the polyurethane resin, the soft segment preferably has a weight average molecular weight (Mw) of 1000 g / mol to 3000 g / mol. In order to exhibit the effect of improving durability due to the introduction of the primer layer, the soft segment preferably has a weight average molecular weight of 1000 g / mol or more. However, if the molecular weight of the soft segment is too large, the glass transition temperature of the polyurethane resin may deviate from the preferred range. Therefore, the soft segment preferably has a weight average molecular weight of 3000 g / mol or less.

[0056] In the present invention, the weight average molecular weight (Mw) can be measured using gel permeation chromatography (GPC) under the following conditions after completely dissolving the compound to be measured in a solvent.

[0057] - Analytical instrument: PL-GPC 220 system

[0058] - Column: 2 × PLGEL MIXED-B (7.5×300mm)

[0059] - Solvent: Trichlorobenzene (TCB) + 0.04 wt% dibutylhydroxytoluene (BHT) (after drying with 0.1% CaCl2)

[0060] - Injector, detection temperature: 160 ℃

[0061] - Flow rate: 1.0 ml / min

[0062] - Injection volume: 200 ㎕

[0063] - Standard sample: polystyrene

[0064]

[0065] According to one embodiment of the invention, it is preferable that the primer layer is formed from a composition comprising the polyurethane resin and a carbodiimide-based curing agent.

[0066] The above carbodiimide-based curing agent strengthens the adhesion between the organic layer including the transparent substrate and the primer layer, and increases the degree of curing of the primer layer, thereby enabling improvement of barrier properties.

[0067] In order to ensure that the above effect can be sufficiently expressed, the carbodiimide-based curing agent may be included in an amount of 1 to 10 parts by weight per 100 parts by weight of the polyurethane resin.

[0068]

[0069] According to one embodiment of the invention, the primer layer may have a thickness of 50 nm to 120 nm.

[0070] To ensure sufficient durability improvement, the thickness of the primer layer is preferably 50 nm or greater. However, if the primer layer is too thick, the adhesion to the organic layer, including the transparent substrate, may be relatively reduced compared to the adhesion to the inorganic barrier layer. Therefore, the thickness of the primer layer is preferably 120 nm or less.

[0071] More preferably, the thickness of the primer layer may be 50 nm to 110 nm, or 60 nm to 110 nm, or 60 nm to 100 nm.

[0072]

[0073] The above inorganic barrier layer is a thin film made of an inorganic material and is a main component layer that enables the laminate to exhibit moisture and oxygen barrier properties.

[0074] Such an inorganic barrier layer may be formed of one or more inorganic materials selected from the group consisting of silicon oxide, silicon nitride oxide, silicon nitride, aluminum oxide, and aluminum nitride.

[0075]

[0076] According to one embodiment of the invention, the inorganic barrier layer may have a thickness of 1 nm to 200 nm.

[0077] To ensure that the appropriate properties as a barrier layer can be realized, the thickness of the inorganic barrier layer is preferably 1 nm or greater. However, if the inorganic barrier layer is too thick, curling due to stress or cracking may occur even with slight bending. Therefore, the thickness of the inorganic barrier layer is preferably 200 nm or less.

[0078] More preferably, the thickness of the inorganic barrier layer may be 1 nm to 150 nm, or 5 nm to 150 nm, or 5 nm to 100 nm, or 10 nm to 100 nm.

[0079]

[0080] According to one embodiment of the invention, the inorganic barrier layer can be formed on the transparent substrate by a method conventional in the technical field to which the present invention pertains.

[0081] For example, as a method for laminating the inorganic barrier layer, an appropriate method may be selected from physical vapor deposition (PVD) or chemical vapor deposition (CVD).

[0082] Preferably, as a method for laminating the inorganic barrier layer, an evaporation method such as thermal evaporation and electron-beam evaporation; or sputtering may be selected.

[0083]

[0084] For example, the evaporation method is the most basic thin film forming method, which is a method of forming a thin film by heating and evaporating a source of metal and non-metal and condensing it on the surface of a substrate at a low temperature. According to one embodiment of the invention, among the evaporation methods, thermal deposition may be preferably selected as a method of laminating the inorganic barrier layer. The thermal deposition may be performed at an initial vacuum of 10 -4 This is a deposition method that requires a vapor pressure of about 10 torr and heats the source by applying electricity to a boat carrying the source to be evaporated and utilizing the resistive heat generated by the boat. The deposition rate in the thermal deposition can be changed by controlling the amount of current supplied to the filament. In addition, a reactive gas (oxygen gas) can be added to react and form an oxide film (AlOx, SiOx, etc.).

[0085]

[0086] As another example, the sputtering can be preferably used because it can easily form a dense thin film with excellent reproducibility over a large area. Preferably, the method for laminating the inorganic barrier layer may be reactive sputtering using the inorganic target and a reactive gas (e.g., oxygen). In the reactive sputtering, the reactive gas is additionally introduced into the system in addition to argon (Ar), which is a plasma generating gas. In the reactive sputtering, it is preferable to precisely control the amount of the reactive gas in the system using devices such as a plasma emission monitor and a mass flow controller. This is because the stoichiometric ratio of the inorganic thin film to be formed must be correct. By adjusting the amount of the reactive gas introduced, stable film formation is possible, and the inorganic barrier layer having excellent barrier properties can be formed.

[0087]

[0088] Meanwhile, the laminate may further include layers that are typically laminated in the technical field to which the present invention pertains in addition to the layers described above.

[0089]

[0090] For example, the laminate may further include an inline coating layer between the transparent substrate and the primer layer.

[0091] The above-mentioned inline coating layer may contain a polymer binder and an antistatic agent. The inline coating layer can prevent the laminate from sticking to each other during the process of winding the laminate roll by alleviating static electricity generated by friction, and can help air introduced during the winding process to easily escape. In addition, the inline coating layer can prevent printing defects caused by static electricity during the printing process for the laminate, and can control feeding characteristics during other post-processing processes.

[0092] The above-mentioned inline coating layer may include a polymer binder and an antistatic agent conventional in the technical field to which the present invention pertains. Preferably, the polymer binder may be a polyester copolymer; and the antistatic agent may be a quaternary ammonium compound, an alkyl sulfonator compound, an alkyl sulfate compound, or the like.

[0093]

[0094] As another example, the laminate may further include a protective layer laminated on the flock barrier layer.

[0095] The protective layer can minimize cracks or separation between layers of the inorganic barrier layer due to deformation such as bending. The protective layer can include at least one compound selected from the group consisting of a urethane polymer, a siloxane polymer, a silane polymer, an acrylic polymer, an olefin polymer, an epoxy polymer, polyethylene terephthalate, and a polycarbonate.

[0096]

[0097] Meanwhile, according to one embodiment of the invention, the laminate can be used as a food packaging material. In addition, the laminate can be applied to various electronic devices such as liquid crystal displays, solar cells, touch panels, organic EL devices, organic TFTs, organic semiconductor sensors, organic light-emitting devices, film capacitors, inorganic EL devices, and color filters, or can be used as a packaging material for the electronic devices.

[0098]

[0099] The moisture and oxygen barrier laminate according to the present invention has improved durability. The laminate can maintain excellent interlayer adhesion even when subjected to external factors such as heating or bending, thereby exhibiting excellent moisture and oxygen barrier properties.

[0100]

[0101] Hereinafter, preferred embodiments are presented to aid understanding of the invention. However, the following examples are intended only to illustrate the invention and are not intended to limit the invention to these embodiments.

[0102]

[0103] Example 1

[0104] A 12 ㎛ thick PET film was prepared as a transparent substrate. A coating solution containing an acrylic-polyester copolymer and an alkyl phosphate-based antistatic agent was coated (Mayer Bar #4) on the transparent substrate to form an inline coating layer.

[0105] A primer composition containing 6 parts by weight of a carbodiimide-based curing agent was prepared for 100 parts by weight of a polyurethane resin (soft segment content: 65 wt%; soft segment Mw: 1000-3000 g / mol; manufactured by DIC Co.) having a glass transition temperature of 10°C. The primer composition was bar-coated on the inline coating layer to form a primer layer having a thickness of 60 nm.

[0106] The laminate including the above primer layer was fixed with tape to the plate of thermal deposition equipment (model name: Daon-100-TE, manufacturer: DAON), and after placing the Al chip (purity 99.999%) on the boat, the rotary pump and diffusion pump were turned on to create a vacuum state (4.4X10 -5 torr). Aluminum oxide (AlOx) was deposited on the primer layer to a thickness of 10 nm under the conditions of an evaporation rate of 2.0 Å / s, an oxygen flow rate of 23 sccm, a working time of 19.8 s, and an applied current of 175.2 A to form the inorganic barrier layer.

[0107] A solution containing a urethane polymer was bar-coated on the inorganic barrier layer and dried with hot air to form a protective layer.

[0108]

[0109] Example 2

[0110] A laminate was obtained in the same manner as in Example 1, except that the primer layer was formed to a thickness of 80 nm.

[0111]

[0112] Example 3

[0113] A laminate was obtained in the same manner as in Example 1, except that the primer layer was formed to a thickness of 100 nm.

[0114]

[0115] Example 4

[0116] A laminate was obtained in the same manner as in Example 1, except that a polyurethane resin having a glass transition temperature of 0°C (soft segment content: 25 wt%; soft segment Mw: 1000 to 3000 g / mol; manufacturer: DIC Co.) was used as the polyurethane resin included in the primer composition.

[0117]

[0118] Comparative Example 1

[0119] A laminate was obtained in the same manner as in Example 1, except that the inorganic barrier layer was formed on the inline coating layer without forming the primer layer.

[0120]

[0121] Comparative Example 2

[0122] A laminate was obtained in the same manner as in Example 2, except that a polyurethane resin having a glass transition temperature of -10°C (soft segment content: 10 wt%; soft segment Mw: 1000 to 3000 g / mol; manufacturer: DIC Co.) was used as the polyurethane resin included in the primer composition.

[0123]

[0124] Comparative Example 3

[0125] A laminate was obtained in the same manner as in Example 2, except that a polyurethane resin having a glass transition temperature of 52°C (soft segment content 80 wt%; soft segment Mw 1000-3000 g / mol; manufacturer DIC Co.) was used as the polyurethane resin included in the primer composition.

[0126]

[0127] Comparative Example 4

[0128] A laminate was obtained in the same manner as in Example 3, except that a polyurethane resin having a glass transition temperature of 46°C (soft segment content 98 wt%; soft segment Mw 1000-3000 g / mol; manufacturer DIC Co.) was used as the polyurethane resin included in the primer composition.

[0129]

[0130] Exam example

[0131] (1) Moisture barrier evaluation

[0132] Using a moisture permeability analyzer (model name: AQUATRAN 2 WVTR Analyzer, manufacturer: Mocon), the moisture permeability was measured at a depth of 50 cm under conditions of 40°C and 90% relative humidity according to the standard test method of ASTM F1249. 2 After mounting the laminated sample, the moisture permeability ratio (g / m) 2 *day) was measured.

[0133]

[0134] (2) Oxygen barrier evaluation

[0135] Oxygen permeability analyzer (model name: OX-Tran 2 / 21 OTR Analyzer, manufacturer: Mocon) was used to measure the oxygen permeability at a distance of 50 cm under the conditions of 23 ℃ and 0% relative humidity according to the standard test method of ASTM D3985. 2 After mounting the laminated sample, the oxygen permeation rate (cc / m 2 *day) was measured.

[0136]

[0137] (3) Peel test

[0138] An adhesive composition was prepared by mixing 15.3 g of a polyester-based two-component adhesive (product name: TM-585-60K, solid content 60 wt%), 1.9 g of a hardener (product name: CAT-10, solid content 75 wt%), and 25.2 g of a solvent (ethyl acetate). The adhesive composition was bar coated (#12, based on a thickness of 5 μm) on the protective layer of the laminate, and then dried with hot air (100°C, 20 s) to form an adhesive layer having a thickness of 5 μm. A CPP film was laminated on the adhesive layer, and aged at 45°C for 1 day to prepare a test sample.

[0139] After attaching two sheets of double-sided tape on the measuring plate of a peel tester (model name: AR-1000, manufacturer: ChemInstruments), the test sample cut to a width of 1.5 cm was attached, and a 180° peel test was performed according to the standard test method of ASTM D3330 to obtain the peel strength value (gf / 15mm).

[0140]

[0141] (4) Peeling test after high temperature treatment

[0142] A test sample was prepared in the same manner as in the above 『(3) Peeling Test』. The test sample was heated for 1 hour at 125°C, which is the sterilization condition for retort food packaging, and then a 180° peel test was performed in the same manner as in the above 『(3) Peeling Test』 to obtain a peel strength value (gf / 15mm).

[0143]

[0144] (5) Blocking test

[0145] In the above examples and comparative examples, after forming a primer layer, it was confirmed whether a blocking phenomenon occurred when the material was wound to a length of 100,000 m at 25°C. However, the above test was not performed on Comparative Example 1, in which a primer layer was not formed.

[0146]

[0147] Example 1 Example 2 Example 3 Example 4 Moisture barrier (g / m 2 *day)0.80.60.30.5Oxygen barrier (cc / m) 2 *day)0.70.50.20.5Peel strength (gf / 15mm)532540533545Peel strength after high temperature treatment (gf / 15mm)480488482450Blocking occurrence (O,X)XXXX

[0148]

[0149] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Moisture Barrier (g / m 2 *day)5345 oxygen barrier (cc / m2 *day)4354Peel strength (gf / 15mm)227235498Peel strength after high temperature treatment (gf / 15mm)12084057Blocking occurrence (O,X)-OXX

[0150]

[0151] Referring to Table 1 above, the laminates according to the above examples did not exhibit blocking during the manufacturing process and exhibited excellent moisture and oxygen barrier properties. In particular, the laminates according to the above examples exhibited significantly higher initial peel strength than the comparative examples, and also exhibited high peel strength even after high-temperature treatment.

[0152] In contrast, referring to Table 2 above, the laminate of Comparative Example 1 exhibited a peel strength less than half that of the examples and poor barrier properties. The laminates of Comparative Examples 2 to 4 showed significantly lower peel strengths and poor barrier properties than those of Comparative Example 1 despite the application of a primer layer.

[0153]

[0154] Although the present invention has been described above through limited embodiments, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. Includes a primer layer and an inorganic barrier layer sequentially formed on one side of a transparent substrate, The above primer layer has a glass transition temperature (T) of 0°C to 20°C. g ), including a polyurethane resin having Laminate.

2. In paragraph 1, A laminate in which the polyurethane resin comprises 30 to 80 wt% of a hard segment having a unit formed by combining diisocyanate and diol, and 20 to 70 wt% of a soft segment having a polyether or polyester unit.

3. In paragraph 2, A laminate wherein the soft segment has a weight average molecular weight of 1000 g / mol to 3000 g / mol.

4. In paragraph 1, A laminate, wherein the primer layer is formed from a composition comprising the polyurethane resin and a carbodiimide-based curing agent.

5. In paragraph 4, A laminate, wherein the carbodiimide-based curing agent is included in an amount of 1 to 10 parts by weight based on 100 parts by weight of the polyurethane resin.

6. In paragraph 1, A laminate in which the above transparent substrate is a plastic film comprising at least one polymer selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, cycloolefin polymer, cycloolefin copolymer, polycarbonate, and poly(methyl methacrylate).

7. In paragraph 1, A laminate in which the above-mentioned inorganic barrier layer is made of at least one inorganic material selected from the group consisting of silicon oxide, silicon nitride oxide, silicon nitride, aluminum oxide, and aluminum nitride.

8. In paragraph 1, The above transparent substrate is a laminate having a thickness of 5 ㎛ to 300 ㎛.

9. In paragraph 1, A laminate, wherein the primer layer has a thickness of 50 nm to 120 nm.

10. In paragraph 1, A laminate, wherein the above-mentioned inorganic barrier layer has a thickness of 1 nm to 200 nm.

11. In paragraph 1, A laminate further comprising an inline coating layer containing a polyester copolymer and an antistatic agent between the transparent substrate and the primer layer.