KR101159158B1 - Environmentally friendly multi-layer barrier film and preparation method thereof - Google Patents

Abstract

The multilayer barrier film of the present invention comprises a barrier layer formed by laminating a barrier layer made of polyvinyl alcohol having a melting temperature of 170 ° C to 220 ° C and a protective layer made of polylactic acid or polyethylene terephthalate having a melting temperature of 205 ° C or lower. It is possible to freely adjust the thickness of gas to improve the gas barrier property, and the hydrophobic polymer film is coated on the surface of one or both outermost layers to provide excellent water barrier property and excellent biodegradability using eco-friendly resin. Do.

Description

Eco-friendly multilayer barrier film and its manufacturing method {ENVIRONMENTALLY FRIENDLY MULTI-LAYER BARRIER FILM AND PREPARATION METHOD THEREOF}

The present invention relates to an environmentally friendly multilayer film having excellent gas / moisture barrier properties, which can be used as a packaging material, and a manufacturing method thereof.

Thermoplastic resin films such as polypropylene films and polyethylene terephthalate films derived from petroleum have excellent mechanical strength and are widely used as packaging films because of their excellent workability. However, due to the low barrier to gas, its use is limited for applications where the package must be kept very safe from the action of external gases, in particular atmospheric oxygen, or the gas composition in the package must be kept constant. to be. Accordingly, in order to impart gas barrier functions such as oxygen barrier property, laminating a resin layer having gas barrier property such as polyvinyl alcohol (PVOH) system on the surface of the thermoplastic resin film has been developed.

Republic of Korea Patent Publication No. 2001-21633, a transparency, barrier comprising a polyester base film of 5㎛ to 50㎛ formed on one side a coating layer comprising a water-dispersible copolymer polyester having PVOH and sulfonyloxy residues A composite polyester film having excellent resistance to sex and mechanical stress is disclosed.

In addition, Korean Patent Laid-Open Publication No. 2004-37065 discloses that a gas barrier layer made of a hydrolyzate of silicon alkoxide, a layered silicate and a PVOH-based resin is coated on a base layer made of a thermoplastic resin film, and the silicon is interposed between the layers of the internal silicate. The film which is comprised so that an alkoxide exists and has excellent gas barrier property even in the high humidity exceeding 90% RH is disclosed.

In addition, Korean Patent Laid-Open Publication No. 2002-92812 has a structure in which a gas barrier layer made of PVOH-based resin, silicon alkoxide hydrolyzate and polyethylene oxide is coated on one side of a thermoplastic resin film and a sealing layer is laminated on the opposite side. As a result, a film having excellent appearance and excellent gas barrier property under high humidity is disclosed.

However, the conventional method of implementing barrier properties by coating PVOH resin has a limitation that coating is not possible beyond a certain thickness, and the thicker the thickness, the weaker the adhesive strength of the coating. In order to produce an additional lamination process after film production, there is a problem in that production efficiency is lowered.

Therefore, it is required to develop a barrier film that can solve the above problems by laminating a PVOH resin layer without coating, and also to develop a film having improved barrier property against moisture as well as gas for use as a food packaging material. This is required.

Republic of Korea Patent Publication No. 2001-21633 Republic of Korea Patent Publication No. 2004-37065 Republic of Korea Patent Publication No. 2002-92812

Accordingly, it is an object of the present invention to provide a novel multilayer barrier film and a method for producing the same having improved barrier properties against gas and moisture.

According to the above object, the present invention includes at least one layer of a first resin layer made of polyvinyl alcohol having a melting temperature of 170 ° C to 220 ° C, and a second water consisting of polylactic acid or polyethylene terephthalate having a melting temperature of 205 ° C or less. Provided is a multilayer film including two or more layers, wherein outermost outer layers are second resin layers, and a hydrophobic polymer film is coated on one or both outermost layers.

According to another object of the present invention, the present invention provides a) a polyvinyl alcohol (PVOH) resin having a melting temperature (Tm) of 170 ° C to 220 ° C as a first resin, and a polylactic acid (PLA) resin or melting temperature as a second resin. Melting each of polyethylene terephthalate (PET) resin that is 205 ° C. or less; b) extruding and laminating the molten first and second resins to obtain a laminated film including at least one first resin layer and at least two second resin layers, wherein both outermost layers are second resin layers. step; And c) longitudinally stretching the laminated film, coating a hydrophobic polymer film on the surface of one or both outermost layers, and laterally stretching and heat-setting the laminated film.

The multilayer barrier film of the present invention is excellent in biodegradability by using an environmentally friendly resin, the thickness of the PVOH layer can be adjusted to further improve the barrier property against the gas, and has a protective layer so that physical properties are not easily degraded. Do not. In addition, the hydrophobic polymer film is coated to provide excellent barrier property against moisture, and can be manufactured at once by in-line coating without additional processes.

1 is a graph measuring the change in air permeability over time for the film according to the present invention and the film according to the prior art.

Hereinafter, the present invention will be described in more detail.

In the film of the present invention, polyvinyl alcohol (PVOH) used as the resin forming the barrier layer (first resin layer) is not biomass but is biodegradable resin.

In general, since the PVOH resin has a similar melting temperature (Tm) and decomposition temperature (Td), it is impossible to obtain a film by an extrusion process. Therefore, in order to use PVOH resin as a barrier film, the coating method was mainly used conventionally. However, when the coating method is used, the coating is not possible beyond a specific thickness, and as the thickness becomes thick, there is a disadvantage in that the adhesive strength of the coating is weakened, and there is a problem in that the protective layer is difficult to be laminated. Thus, in the present invention, in order to lower the melting temperature (Tm) than the decomposition temperature (Td) using a modified PVOH resin with a melting temperature of 170 ℃ to 220 ℃, to produce a PVOH layer through the extrusion process with such PVOH resin Done.

More preferably, the PVOH resin used in the present invention has a melting temperature of 180 ° C to 200 ° C and a decomposition initiation temperature of at least 10 ° C or higher than the melting temperature. Moreover, it is preferable that polymerization degree is the range of 300-3,000.

As a result, the thickness can be freely adjusted to further improve the barrier property. Preferably, the thickness of the barrier layer (first resin layer) is 100 nm to 100 μm. This is a numerical value compared with that of the conventional PVOH barrier layer manufactured using the coating method, which had to be about 1 μm or less. As a result, the film of the present invention may improve the barrier property to the gas, preferably, the air permeability to oxygen according to ASTM D3985 is less than 10cc / ㎡.day.

In the multilayer barrier film of the present invention, a PVOH layer as a barrier layer (first resin layer) is used as an inner layer, and a protective layer (second resin layer) is disposed at the outermost layer, whereby PVOH is directly exposed to the external environment. This prevents the physical property from falling. In the case of the conventional film, the barrier property is deteriorated because the PVOH-coated film must be printed directly without such a protective layer.

In the present invention, the protective layer (second resin layer) is made of polylactic acid (PLA) or polyethylene terephthalate (PET). When PET is used as the protective layer, since the melting temperature of general PET is higher than the PVOH decomposition start temperature, it is difficult to apply to the coextrusion process. In the present invention, the melting temperature is modified so that the melting temperature is lower than the PVOH decomposition start temperature. PET having a melting temperature of 205 ° C. or lower, for example, 180 ° C. to 205 ° C. is used.

The preferred weight average molecular weight (Mw) of PLA used in the present invention is 50,000 to 300,000, and the preferred weight average molecular weight (Mw) of PET is 10,000 to 60,000.

In the barrier film of the present invention, the three-layer film can be configured as a protective layer / barrier layer / protective layer, and more than three layers of the protective layer / barrier layer / barrier layer / protective layer, protective layer / barrier layer. A configuration such as a protective layer / barrier layer / protective layer is possible.

When the thickness of each resin layer becomes thick, the bonding force between the resin layers may be reduced, and thus an adhesive layer may be further included between the resin layers. For example, the structure of the protective layer / adhesive layer / barrier layer / adhesive layer / protective layer can be considered. As the adhesive layer, a layer made of one or more resins selected from polyethyleneimine, polyurethane, and the like can be used.

In the film of the present invention, the thickness of the protective layer (second resin layer) is preferably 1 µm to 150 µm, and the thickness of the entire multilayer barrier film is preferably 5 µm to 200 µm.

Nano-lamination is also possible by controlling the thickness of each resin layer, in which case the adhesion between the resin layers can be further improved.

In the film of the present invention, in order to increase the barrier property against moisture and protect the PVOH layer vulnerable to moisture, a hydrophobic polymer film is coated on the surface of one or both outermost layers of the multilayer film.

The hydrophobic polymer that can be coated on the film of the present invention can be any polymer as long as it has a moisture barrier property, and may be, for example, an acryl, polyethylene, or polypropylene polymer.

It is preferable that the thickness of such a hydrophobic polymer membrane is 0.01 micrometer-3 micrometers.

Due to such a coating layer, the film of the present invention may improve the barrier property against moisture, and preferably, the water vapor transmission rate according to ASTM F1249 is 30 g / m 2 .day or less.

The multilayer barrier film of the present invention comprises a) melting a PVOH resin having a melting temperature (Tm) of 170 ° C to 220 ° C as a first resin, and a PLA resin or a PET resin having a melting temperature of 205 ° C or less as a second resin, respectively. Making a step; b) extruding and laminating the molten first and second resins to obtain a laminated film including at least one first resin layer and at least two second resin layers, wherein both outermost layers are second resin layers. step; And c) longitudinally stretching the laminated film and coating a hydrophobic polymer film on the surface of one or both outermost layers, followed by stretching and heat setting in the transverse direction.

In the manufacturing method, the temperature in the melting and extrusion process is preferably 170 ° C to 250 ° C, more preferably 170 ° C to 220 ° C.

In the extrusion and lamination processes in step b), the first resin and the second resin may be co-extruded and laminated, or may be laminated by extruding each of them by using an adhesive layer. In the case of using coextrusion, the molten first resin and the second resin can be coextruded so as to have a desired film structure, thereby obtaining a laminated film. In the case of using an adhesive layer, the first resin layer and the second resin layer are extruded to obtain a first resin layer and a second resin layer, respectively, and then the adhesive layer is coated on the first resin layer or the second resin layer. A 1st resin layer or a 2nd resin layer is bonded here, and the laminated | multilayer film of a desired structure can be obtained.

In the step c), the stretching and heat setting temperature is preferably 80 ℃ to 200 ℃, the stretching ratio is preferably 1 to 8 times. In addition, the coating of the hydrophobic polymer membrane may be performed by coating, for example, an aqueous acrylic solution or a wax / dispersed aqueous solution of polyethylene / polypropylene series. The hydrophobic polymer film is dried after undergoing a heat treatment at a temperature of 600 ~ 800 ℃ after coating, and complete drying is carried out after the lateral stretching process.

Such a multilayer barrier film of the present invention can adjust the thickness of the PVOH layer can further improve the gas barrier properties than in the prior art, including the protective layer does not easily degrade the physical properties. In addition, by coating a hydrophobic polymer film on the surface of the film to more completely protect the PVOH layer, the barrier properties against moisture are also very good. Since the hydrophobic polymer membrane is inline coated, it can be manufactured at a time in an existing process without additional processes. In addition, it is environmentally friendly and in particular when using PLA as the protective layer resin can further increase the biodegradability of the entire film.

Therefore, the multilayer barrier film of the present invention can be used in fields requiring environmental friendliness and barrier properties against gas and moisture, for example, food packaging materials.

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are illustrative of the present invention, and the present invention is not limited to the following examples.

EXAMPLES Preparation of a Multilayer Barrier Film According to the Present Invention

In the following Examples 1 and 2, the following were used as a raw material resin.

PVOH PLA PET manufacturer Nippon gohsei Nature works SKC product name Nichigo G-polymer 4032D XTP10 Tg (占 폚) 75 60 85 Tc (℃) 93 110 130 Tm (占 폚) 183 170 205 Decomposition start temperature (℃) 240 ↑ 240 ↑ 300 ↑ Mw or degree of polymerization 20,000 ~ 80,000 150,000 ~ 200,000 150,000-40,000

Example 1: Production of PLA / PVOH / PLA Multi-layer Coextrusion Film Coated with One Side Acrylic Film

As the first resin, a polyvinyl alcohol resin (G-polymer, Nippon Gohsei) having a melting temperature of 183 ° C was used, and a polylactic acid resin (4032D, NatureWorks) having a melting temperature of 170 ° C was used as the second resin.

Each of the raw material resins was melt extruded at 220 ° C. such that the thickness ratio of the second resin layer / first resin layer / second resin layer was 5: 1: 1 through three extruders, and then laminated in three layers in a feed block. .

The laminated film was brought into close contact with a casting roll at 15 ° C. and stretched at 80 ° C. with a 3.0 × longitudinal stretch ratio. Thereafter, an aqueous acrylic solution (40 wt% solids, vc2200, MICHELMAN) was coated on one surface of the laminated film with a wet thickness of 16.4 μm by a coater (coater, Mayer rod # 6). After passing through the IR heater of 600 ~ 800 ℃, it was stretched at 90 ℃ with a transverse stretching ratio 4 times. This was heat-set at 100 ° C. to obtain a multilayer coextrusion film having a total thickness of 21.6 μm with one side coated with an acrylic polymer film having a thickness of 1.6 μm.

Example 2 Preparation of PLA / PVOH / PLA Multi-layer Coextrusion Film Coated with Acrylic Polymer Membrane

When the acrylic aqueous solution was coated, the same procedure as in Example 1 was carried out except that the wet film was coated with a wet thickness of 16.4 μm on both sides of the laminated film, and a total of 1.6 μm thick acrylic polymer films were coated on both sides. A multilayer coextrusion film having a thickness of 23.2 μm was obtained.

Example 3: Preparation of PET / PVOH / PET Multi-layer Coextrusion Film Coated with One Side Acrylic Film

The same procedure as in Example 1 was carried out except that polyethylene terephthalate resin (XTP10, SKC) having a melting temperature of 205 ° C. was used as the second resin, and the melt extrusion temperature of the second resin was set to 240 ° C. Thus, a multilayer coextrusion film having a total thickness of 21.6 μm with one side coated with an acrylic polymer film of 1.6 μm in thickness was obtained.

Example 4 Preparation of PLA / Adhesive Layer / PVOH / Adhesive Layer / PLA Multilayer Bonded Film Coated with One Side Acrylic Film

As the first resin, a polyvinyl alcohol resin (G-POLYMER, Nippon Gohsei) having a melting temperature of 183 ° C was used, and a polylactic acid resin (4032D, NatureWorks) having a melting temperature of 170 ° C was used as the second resin. As the adhesive resin, a polyurethane resin having a melting temperature of 205 ° C was used.

The first resin and the second resin were melt-extruded at 220 ° C. so as to have a thickness ratio of 5: 1 through an extruder, thereby preparing respective first and second resin layers. This was laminated in the order of the second resin layer / the first resin layer / the second resin layer, the adhesive resin is coated between each resin layer and bonded to prepare a laminated film.

The obtained laminated film was stretched / coated and heat-set as in Example 1 to obtain a multilayer coextrusion film having a total thickness of 21.6 μm with one side coated with an acrylic polymer film having a thickness of 1.6 μm.

Example 5: Preparation of PLA / PVOH / PLA Multi-layer Coextrusion Film Coated with One Side of PE / PP Series Polymer Membrane

The same procedure as in Example 1 was carried out, except that PE / PP-based resin (Michem ^TM Lube693, MICHELMAN Co., Ltd.) was used as the hydrophobic polymer instead of acrylic aqueous solution. A multilayer coextrusion film having a total thickness of 21.6 μm was obtained.

Comparative Example: Preparation of Barrier Film According to the Prior Art

In the following Comparative Examples 1-5, the following was used as raw material resin.

PVOH PLA PET EVOH PVdC  manufacturer OCI Nature works SKC Kuraray Asahi Kasei product name POLINOL 4032D CTF41 EVAL PVDC LATEX Tg (占 폚) 85 60 80 48 -17 Tc (℃) 110 130 Tm (占 폚) 230 170 255 160 200 Decomposition start temperature (℃) 200 ↑ 240 ↑ 300 ↑ 220 ↑ 200 ↑ Mw or degree of polymerization 20,000 ~ 80,000 150,000 ~ 200,000 3.50,000-40,000 150,000-30,000 50,000 ~ 100,000

Comparative Example 1: Preparation of PVOH Coated Film (Base Film-PLA)

As a base film, polylactic acid resin (4032D, NatureWorks Co., Ltd.) whose melting temperature was 170 degreeC was melt-extruded at 220 degreeC, contact | adhered to the casting roll of 15 degreeC, and extended | stretched at 80 degreeC by 3.0 times of longitudinal stretch ratio. After coating a solution containing 3% by weight of polyvinyl alcohol (POLINOL, OCI) having a melting temperature of 210 to 230 ° C. with a wet thickness of 16.4 μm by a coater (Mayer rod # 6), the transverse draw ratio was 3.8 times. It extended | stretched at 130 degreeC. It was heat set at 230 ° C. to obtain a biaxially oriented coated film having a thickness of 20 μm.

Comparative Example 2: Preparation of PVOH Coated Film (Base Film-PET)

Except that the polyethylene terephthalate resin (CTF41, SKC Co., Ltd.) having a melting temperature of 255 ° C was melt-extruded at 285 ° C as a base film, was brought into close contact with a casting roll at 15 ° C, and stretched at 80 ° C with 3.0 times the longitudinal drawing ratio. , The same procedure as in Comparative Example 1 was carried out to obtain a biaxially oriented coating film having a thickness of 20 μm.

Comparative Example 3: Preparation of PLA Single Layer Film

Polylactic acid resin (4032D, NatureWorks) having a melting temperature of 170 ° C was melt-extruded at 220 ° C. The resultant was brought into close contact with a casting roll at 15 ° C. and stretched at 80 ° C. with a longitudinal draw ratio of 3.0 times and at 90 ° C. with a transverse draw ratio of 3.8. It was heat set at 100 ° C. to obtain a biaxially oriented monolayer film having a thickness of 20 μm.

Comparative Example 4: Preparation of EVOH Multi-layer Coextrusion Film

EVOH (EVAL, Kuraray) having a melting temperature of 160 ° C. was used as the first resin, and polylactic acid resin (4032D, NatureWorks) having a melting temperature of 170 ° C. was used as the second resin.

Each of the raw material resins was melt extruded at 220 ° C. such that the thickness ratio of the second resin layer / first resin layer / second resin layer was 5: 1: 1 through three extruders, and then laminated in three layers in a feed block. .

The laminated film was brought into close contact with a casting roll at 15 ° C. and stretched at 70 ° C. at a 3.0 times longitudinal stretch ratio, and stretched at 90 ° C. at a lateral stretch ratio 3.8 times. This was heat-set at 100 ° C. to obtain a biaxially stretched three-layer coextrusion film having a thickness of 20 μm.

Comparative Example 5: Preparation of PVdC Coating Film (Base Film-PET)

The polyethylene terephthalate resin (CTF41, SKC) whose melt temperature was 255 degreeC was melt-extruded at 285 degreeC, contact | adhered to the casting roll of 15 degreeC, and extended | stretched at 105 degreeC by 3.0 times of longitudinal stretch ratio. On it, a solution containing 50 wt% of PVdC resin (PVDC LATEX, Asahi Kasei Co., Ltd.) having a melting temperature of 200 ° C. was coated with a wet thickness of 16.4 μm by a coater (Mayer rod # 8), followed by a transverse draw ratio of 3.8. Stretched at 130 degreeC by boat. It was heat set at 230 ° C. to obtain a biaxially oriented coated film having a thickness of 20 μm.

Test Example

Test Example 1 Measurement of Air Permeability to Oxygen

For the films obtained in the above examples and comparative examples, the air permeability to oxygen was measured using an air permeability meter (OX-TRAN, MOCON) according to ASTM D3985. Furthermore, after printing on the surface of each film, air permeability was measured in the same manner. The results are shown in Table 3 below.

division Example Comparative example One 2 3 4 5 One 2 3 4 5 Specularity
(cc / ㎡.day) Unprinted 9 9 7 13 10 15 15 900 15 20 After printing 9 9 7 13 10 20 20 920 16 20

As shown in Table 3, the barrier film of the embodiment according to the present invention can be seen that the barrier property against oxygen is more excellent than the barrier film of the comparative example prepared in a conventional manner. In addition, while the barrier film of Example maintains low air permeability even after printing, it can be seen that in Comparative Examples 1 to 3 without the protective layer, the barrier property is further reduced after printing.

Test Example 2 Measurement of Air Permeability to Oxygen Under Humidity

For the films obtained in the above Examples and Comparative Examples, the air permeability to oxygen was measured using an air permeability meter (OX-TRAN, MOCON) at 25 ° C., 1 atm and 50% RH in accordance with ASTM D1434. The results are shown in Table 4 below.

division Example Comparative example One 2 3 4 5 One 2 3 4 5 Air permeability (cc / ㎡.day, 50% RH) 10 9 7 13 11 900 40 990 16 20

As shown in Table 5, it can be seen that the barrier film of the embodiment according to the present invention is excellent with little change in air permeability even under high humidity of 50% RH. On the other hand, in the case of the barrier film of the comparative example prepared in the conventional manner, the air permeability was increased further, in particular, in the case of Comparative Example 1, the PVOH coating layer collapsed under 50% RH and showed a similar value as that of Comparative Example 3.

Test Example 3: Measurement of moisture permeability

For the films obtained in the above Examples and Comparative Examples, the moisture permeability was measured using a moisture permeability meter (PERMATRAN, Mocon Co., Ltd.) at 37.8 ° C, 1 atm and 100% RH according to ASTM F1249. The results are shown in Table 5 below.

division Example Comparative example One 2 3 4 5 One 2 3 4 5 Permeability (g / ㎡.day) 20 10 15 20 25 500 100 500 50 20

As shown in Table 5, the barrier film of the embodiment according to the present invention has a lower moisture permeability than the barrier film of the comparative example prepared in a conventional manner, it can be seen that the barrier property against moisture is more excellent.

Test Example 4: Evaluation of the change in air permeability over time

For the films obtained in the above Examples and Comparative Examples, the air permeability was measured for 14 days using an air permeability meter (OX-TRAN, MOCON) according to ASTM D3985 and the results are shown in FIG. 1. However, in order to evaluate the stability to humidity, it was stored under the condition of 50% RH at the time other than measurement.

As shown in Figure 1, it can be seen that the barrier films of Examples 1 to 5 according to the present invention are excellent in barrier property against oxygen due to low air permeability even with time.

On the other hand, in the case of Comparative Example 2, the air permeability increased rapidly from day 1 and already showed the air permeability of 100cc after 5 days. In addition, in the case of Comparative Example 3 was too large (1000cc level) compared to other values it could not be shown in the graph. In the case of Comparative Example 1, the initial air permeability was low due to the PVOH coating, but the PVOH coating layer gradually disappeared due to moisture, and eventually, a value close to 1000 cc, which is the level of the single layer PLA of Comparative Example 3, could not be represented as well. Other Comparative Examples 4 and 5 showed higher air permeability compared to the film of the present invention.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, It is to be understood that the invention may be practiced within the scope of the appended claims.

Claims (12)

A lamination comprising at least one layer of a first resin layer made of polyvinyl alcohol having a melting temperature of 170 ° C. to 220 ° C. and at least two layers of a second resin layer made of polylactic acid or a polyethylene terephthalate having a melting temperature of 205 ° C. or less. As the film, both outermost layers are the second resin layer, the hydrophobic polymer film is coated on the surface of one or both outermost layers, multilayer barrier film.
The method of claim 1,
The multilayer hydrophobic film, characterized in that the hydrophobic polymer film is made of an acrylic, polyethylene, or polypropylene polymer.
The method of claim 1,
The multilayer barrier film, characterized in that the multilayer coextrusion film or multilayer bonding film.
The method of claim 1,
The thickness of each layer of the first resin layer is characterized in that 100nm to 100㎛, multilayer barrier film.
The method of claim 1,
The multilayer barrier film has a water vapor permeability of 10 cc / m 2 .day or less according to ASTM D3985, and a water vapor transmission rate of 30 g / m 2 .day or less according to ASTM F1249.
The method of claim 1,
The laminated film,
Second resin layer / first resin layer / second resin layer;
A second resin layer / first resin layer / first resin layer / second resin layer; or
It has a structure of 2nd resin layer / 1st resin layer / 2nd resin layer / 1st resin layer / 2nd resin layer, The multilayer barrier film characterized by the above-mentioned.
The method of claim 1,
Between the first resin layer and the second resin layer, further comprising an adhesive layer made of a resin selected from polyethyleneimine and polyurethane, multilayer barrier film.
a) melting a polyvinyl alcohol resin having a melting temperature of 170 ° C. to 220 ° C. as a first resin, and a polylactic acid resin or a polyethylene terephthalate resin having a melting temperature of 205 ° C. or less as a second resin, respectively;
b) extruding and laminating the molten first and second resins to obtain a laminated film including at least one first resin layer and at least two second resin layers, wherein both outermost layers are second resin layers. step; And
c) stretching the laminated film in a longitudinal direction, coating a hydrophobic polymer film on the surface of one or both outermost layers, and then stretching and heat setting the laminate film in a transverse direction.
The method of claim 8,
Extrusion and lamination process of the step b) is characterized in that the first resin and the second resin is co-extruded and laminated, characterized in that the manufacturing method of the multilayer barrier film.
The method of claim 8,
In the extrusion and lamination process of step b), the first and second resins are melted, respectively, to obtain a first resin layer and a second resin layer, and then laminated by bonding using an adhesive layer. Method of producing a barrier film.
The method of claim 8,
In the step b), the melt extrusion temperature of the first resin is characterized in that 170 ℃ to 250 ℃, a method for producing a multilayer barrier film.
The method of claim 8,
The coating of the hydrophobic polymer film in step c) is characterized in that the coating of acrylic aqueous solution, or polyethylene / polypropylene-based wax / dispersion solution, characterized in that the method for producing a multilayer barrier film.

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