Single-material packaging material having excellent barrier properties and manufacturing method therefor

Abstract

The present invention relates to a packaging material and a manufacturing method therefor, the packaging material being formed by laminating: an outer layer formed by forming an adhesive layer between a plurality of spiral cross-laminated films and laminating same; a middle layer formed on the outer layer and comprising an ethylene vinyl alcohol (EVOH) resin; and an inner layer formed on the middle layer and comprising a linear low-density polyethylene (LLDPE) resin. According to the present invention, a packaging material which has excellent mechanical properties, such as tensile strength, tear strength, impact strength, elongation, and interlayer peeling force, and excellent gas barrier properties, and which is used for packaging heavy feed or food may be provided. In addition, the packaging material provided by the present invention uses a single polyethylene material and thus may be recycled.

Description

Packaging material with excellent barrier properties of a single material and its manufacturing method

[0001] The present invention relates to a packaging material having excellent barrier properties made of a single material and a method for manufacturing the same, and more specifically, to a packaging material for packaging high-weight pet food having excellent barrier properties made of a single material and a method for manufacturing the same.

[0002] With the recent revision of the Resource Recycling Act, the demand for recyclable packaging materials has increased rapidly, and as the pet market grows in size, the demand for recyclable packaging materials for pet food is also increasing rapidly.

[0003] The existing packaging materials for feed are made of PET or Nylon / Al / LLDPE, which are classified as 'composite materials' and cannot be recycled. Therefore, single materials such as MOPE and BOPE have been developed to replace 'composite materials' with 'single materials' that can be recycled. However, due to limitations in mechanical properties, they could not be applied to packaging materials with relatively high contents loads (over 3 kg). In general, to manufacture multi-layer packaging materials, a method is used in which each layer of film produced by coextrusion (blown or T-die extruder) is laminated by coating an adhesive between the layers with a dry laminating machine.

[0004] However, manufacturing using the above method makes recycling impossible due to the use of composite materials. Furthermore, more than three lamination processes are required using a dry laminating machine. Additionally, post-lamination maturation (40-60°C, 3 days) is required, requiring at least three working days. Furthermore, post-lamination delamination can lead to delamination issues and reduced oxygen / moisture barrier properties, making it difficult to ensure superior quality.

[0005] Accordingly, the present invention provides a packaging material for feed packaging composed of a single polyethylene material, which has excellent impact resistance and standing properties, improved interlayer adhesive strength and oxygen / moisture barrier properties, and secured productivity through in-line production, by applying a CCL film and a single polyethylene material film having equally excellent tear strength in both MD and TD directions to a composite barrier film manufacturing facility, and a manufacturing method thereof.

[0006] The present invention aims to provide a packaging material for heavy-weight pet food, which is recyclable using a single material and has excellent barrier properties, and a manufacturing method thereof, in order to solve the above-mentioned shortcomings of the prior art.

[0007] The present invention provides a packaging material comprising an outer layer formed by forming an adhesive layer between a plurality of spiral cross-laminated films and laminating them; a middle layer formed on the outer layer and containing ethylene vinyl alcohol (EVOH) resin; and an inner layer formed on the middle layer and containing linear low-density polyethylene (LLDPE) resin.

[0008] In addition, the present invention provides a method for manufacturing a packaging material, comprising the steps of: cutting a cylindrical film manufactured by a blown extrusion method using a high-density polyethylene (HDPE) resin at an angle of 22.5 to 67.5 degrees to form a spiral shape; extrusion-coating an adhesive resin of the same material on one sheet of the cut film, and then laminating another sheet of the cut film so that the directional grains of the films intersect to form a spiral cross-laminated film having an alternating directional grain; forming an adhesive layer containing a low-density polyethylene (LDPE) resin between a plurality of the spiral cross-laminated films and laminating them to form an outer layer; sequentially laminating an adhesive LDPE layer, a tie resin layer, an ethylene vinyl alcohol (EVOH) resin layer, a tie resin layer, and an adhesive LDPE layer on the outer layer to form a middle layer; and forming an inner layer containing a linear low-density polyethylene (LLDPE) resin on the middle layer.

[0009] According to the present invention, a CCL film having equally excellent tear strength in both MD and TD directions and a polyethylene single-material film are applied to a composite barrier film manufacturing facility, thereby providing a packaging material used for packaging high-weight (3 to 25 kg) feed or food having excellent mechanical properties such as tensile strength, tear strength, impact strength, elongation, and interlayer peel strength, and excellent gas barrier properties.

[0010] The packaging material provided in the present invention is made of a single polyethylene material and is recyclable.

[0011] The present invention can provide a method for manufacturing a packaging material for feed packaging composed of a single polyethylene material, with productivity secured through in-line production.

[0012] Figure 1 is a schematic diagram of a packaging material according to one embodiment of the present invention.

[0013] Figure 2 is a schematic diagram of a packaging material manufacturing device according to one embodiment of the present invention.

[0014] Hereinafter, the present invention will be described in detail.

[0015] Figure 1 illustrates a packaging material (10) according to one embodiment of the present invention.

[0016] The present invention provides a packaging material comprising an outer layer (20) formed by forming an adhesive layer (23) between a plurality of spiral cross-laminated films (21, 22) and laminating them; a middle layer (30) formed on the outer layer and containing ethylene vinyl alcohol (EVOH) resin; and an inner layer (40) formed on the middle layer and containing linear low-density polyethylene (LLDPE) resin.

[0017] The above spiral cross-laminated film may be a film in which a cylindrical plastic film manufactured by a blown extrusion method is cut into a spiral shape, an adhesive resin of the same material is extruded and coated on one sheet of the cut film, and then another sheet of the cut film is laminated so that the directional grains of the films intersect, thereby forming a film with directional grains in an alternating shape, i.e., a CCL HDPE film. In the present invention, a film in which two sheets of obliquely cut films are cross-laminated to form directional grains in an alternating shape is referred to as a 'CCL film' (Cross Cutting Lamination Film) (spiral cross-laminated film).

[0018] Conventional polyethylene films were either uniaxially oriented polyethylene (MOPE) films or biaxially oriented polyethylene (BOPE) films extruded using the blown process. Therefore, the orientation in the machine direction (MD) was higher than in the transverse direction (TD), resulting in a problem of directional characteristics (split, tearing characteristics).

[0019] To solve these problems, the present invention uses a CCL film having equally excellent tear strength in both MD and TD directions as the outer layer of the packaging material.

[0020] In one embodiment of the present invention, the high-density polyethylene (HDPE) resin may have a density of 0.940 to 0.970 g / cm3 and an MFR (190°C, 2.16 kgf) of 0.01 to 5 g / 10 min.

[0021] If the density of the above high-density polyethylene (HDPE) resin is less than 0.940 g / cm3, the mechanical properties of the blown film deteriorate, and if it exceeds 0.970 g / cm3, the elasticity, flexibility, extensibility, and impact resistance deteriorate. Preferably, the density may be 0.940 to 0.960 g / cm3.

[0022] If the MFR (190°C, 2.16 kgf) of the above high-density polyethylene (HDPE) resin is less than 0.01 g / 10 min, the formability of the blown film deteriorates, and if the MFR (190°C, 2.16 kgf) exceeds 5 g / 10 min, the mechanical properties of the blown film deteriorate. Preferably, the MFR (190°C, 2.16 kgf) may be 0.03 to 0.1 g / 10 min.

[0023] The above spiral cross-laminated film may be a cylindrical film cut at an angle of 22.5 to 67.5° to form a spiral shape.

[0024] In one embodiment of the present invention, the total thickness of the outer layer may be 30 to 120 μm. Preferably, it may be 40 to 80 μm.

[0025] In one embodiment of the present invention, the adhesive layer may include a low-density polyethylene (LDPE) resin.

[0026] In one embodiment of the present invention, the low-density polyethylene (LDPE) resin may have a density of 0.915 to 0.940 g / cm3 and an MFR (190°C, 2.16 kgf) of 3 to 10 g / 10 min.

[0027] If the density of the above low-density polyethylene (LDPE) resin is less than 0.915 g / cm3, the mechanical properties of the blown film deteriorate, and if it exceeds 0.940 g / cm3, the elasticity, flexibility, extensibility, and impact resistance deteriorate. Preferably, the density may be 0.920 to 0.925 g / cm3.

[0028] If the MFR (190°C, 2.16 kgf) of the above low-density polyethylene (LDPE) resin is less than 3 g / 10 min, the formability of the blown film deteriorates, and if the MI exceeds 10 g / 10 min, the mechanical properties of the blown film deteriorate. Preferably, the MFR (190°C, 2.16 kgf) may be 7 to 8 g / 10 min.

[0029] In one embodiment of the present invention, the adhesive layer may be T-die extrusion coated to a thickness of 5 to 20 μm. The thickness deviation of the T-die extrusion coated adhesive layer resin may be at the level of 1 to 2%, thereby providing good smoothness.

[0030] In one embodiment of the present invention, ozone treatment may be performed before formation of the adhesive layer to improve the adhesion between the HDPE outer layer and the LDPE adhesive layer, which have no interlayer adhesion.

[0031] In one embodiment of the present invention, the ozone treatment may be performed at a flow rate of 100 to 200 ml / min. Preferably, high adhesion can be achieved by performing ozone treatment at a flow rate of 120 to 150 ml / min.

[0032] The packaging material of the present invention includes a middle layer comprising ethylene vinyl alcohol (EVOH) resin on the outer layer to impart barrier properties and oxygen and water vapor barrier properties.

[0033] In one embodiment of the present invention, the multilayer may have a structure in which an adhesive LDPE layer, a tie resin layer, an ethylene vinyl alcohol (EVOH) resin layer, a tie resin layer, and an adhesive LDPE layer are sequentially laminated.

[0034] The thickness of the above adhesive LDPE layer may be 10 to 20 μm, the thickness of the Tie Resin layer may be 3 to 5 μm, and the thickness of the ethylene vinyl alcohol (EVOH) resin layer may be 6 to 8 μm.

[0035] Preferably, the above-mentioned layer can be T-die extrusion coated with a thickness of 32 to 52 μm.

[0036] In one embodiment of the present invention, the thickness deviation of the T-die extrusion coated layer can have good smoothness at the level of 1 to 2%.

[0037] In one embodiment of the present invention, the content of ethylene vinyl alcohol (EVOH) resin in the multilayer may be 5% or less of the total layer. Therefore, the packaging material of the present invention may be recognized as a single material.

[0038] In one embodiment of the present invention, the ethylene vinyl alcohol (EVOH) resin in the middle layer may be 27 to 44 mol%, have a density of 1.12 to 1.21 g / cm3, and have an MFR (190°C, 2.16 kgf) of 1 to 8 g / 10 min. mol% refers to the ethylene content.

[0039] The present invention uses an ethylene vinyl alcohol (EVOH) resin having an ethylene content of 27 to 44 mol% in the middle layer, thereby increasing the oxygen barrier property of the middle layer to 0.1 to 1.0 cc / m. 2 / 24hr, and the vapor barrier property is 1.0~5.0g / m 2 / 24hr can be implemented. Preferably, 27 mol% ethylene vinyl alcohol (EVOH) resin is used.

[0040] Preferably, the ethylene vinyl alcohol (EVOH) resin may have a density of 1.12 to 1.19 g / cm3 and an MFR (190°C, 2.16 kgf) of 3 to 5 g / 10 min.

[0041] The packaging material of the present invention includes an inner layer formed on the middle layer as an ultra-low temperature sealing layer and containing linear low density polyethylene (LLDPE) resin.

[0042] In one embodiment of the present invention, the linear low-density polyethylene (LLDPE) resin has a density of 0.870 to 0.940 g / cm 3 And, MFR (190℃, 2.16kgf) may be 1~5g / 10min.

[0043] Preferably, the linear low-density polyethylene (LLDPE) resin has a density of 0.900 to 0.920 g / cm 3 And, MFR (190℃, 2.16kgf) may be 1~2g / 10min.

[0044] In one embodiment of the present invention, the thickness of the inner layer may be 30 to 80 μm.

[0045] The above packaging material can be used for feed packaging or food packaging.

[0046] The above packaging material is made of a single material and can be recycled.

[0047] The above packaging material can be used for packaging with a relatively high load of contents of 3 kg or more.

[0048] In addition, the present invention provides a method for manufacturing a packaging material, comprising the steps of: cutting a cylindrical film manufactured by a blown extrusion method using a high-density polyethylene (HDPE) resin at an angle of 22.5 to 67.5 degrees to form a spiral shape; extrusion-coating an adhesive resin of the same material on one sheet of the cut film, and then laminating another sheet of the cut film so that the directional grains of the films intersect to form a spiral cross-laminated film having an alternating directional grain; forming an adhesive layer containing a low-density polyethylene (LDPE) resin between a plurality of the spiral cross-laminated films and laminating them to form an outer layer; sequentially laminating an adhesive LDPE layer, a tie resin layer, an ethylene vinyl alcohol (EVOH) resin layer, a tie resin layer, and an adhesive LDPE layer on the outer layer to form a middle layer; and forming an inner layer containing a linear low-density polyethylene (LLDPE) resin on the middle layer.

[0049] A composite barrier film manufacturing device can be used in the method for manufacturing the packaging material of the present invention. As an example, the composite barrier film manufacturing device illustrated in Fig. 2 can be used.

[0050] Hereinafter, the present invention will be described in more detail through specific examples and comparative examples.

[0051]

[0052] [ingredient]

[0053] As a high-density polyethylene (HDPE) product, MFR (190℃, 2.16kgf) 0.05g / 10min, density 0.956g / cm 3 SK products were used.

[0054] Low-density polyethylene (LDPE) products have an MFR (190℃, 2.16kgf) of 7.2g / 10min and a density of 0.918g / cm 3 LG Chemical products were used.

[0055] Linear low-density polyethylene (LLDPE) products have an MFR (190℃, 2.16kgf) of 1.0g / 10min and a density of 0.918g / cm 2 LG Chemical products were used.

[0056] As an adhesive resin product, MFR (190℃, 2.16kgf) 9.0g / 10min, density 0.92g / cm 3 Mitsui Chemicals products were used.

[0057] Ethylene vinyl alcohol (EVOH) products have an MFR (190℃, 2.16kgf) of 8.0g / 10min and a density of 1.21g / cm 3 Kuraray products were used.

[0058]

[0059] <Manufacturing Example 1> Manufacturing of CCL HDPE film

[0060] High-density polyethylene (HDPE) (MI 0.05 g / 10 min, density 0.956 g / cm 3 ) 300 kg was fed into the extruder of a blown film forming machine, and a blown film with a thickness of 80 ㎛ was manufactured under the following conditions.

[0061] <Film forming conditions>

[0062] Extrusion cylinder temperature: 170~190℃, die temperature: 170~190℃

[0063] Extrusion capacity: 100 kg / hour

[0064] Circular die: 200mm, die gap width: 0.7mm

[0065] Blow-up ratio: 5~8, take-up speed: 30~40m / min

[0066]

[0067] In cooling the tube bubble, the neck of the bubble was gradually cooled to 80°C by blowing air from the first blower, the expanded portion of the bubble was gradually cooled to 60°C by blowing air from the second blower, the frost line region was gradually cooled to 40°C by blowing air from the third blower, and the bubble region was maintained at 40°C to manufacture a cylindrical plastic film.

[0068] The above cylindrical plastic film was cut at a 45° angle to form a spiral shape, and two cut high-density polyethylene (HDPE) films were cross-laminated in both MD and TD directions and bonded using an adhesive of the same material to obtain a film having a directional grain in an alternating weave shape. This is referred to as a CCL HDPE film.

[0069]

[0070] <Example 1> Manufacturing of packaging material

[0071] After ozone treatment at a flow rate of 100 to 200 ml / min on the CCL HDPE film manufactured in Manufacturing Example 1, the CCL HDPE film manufactured in Manufacturing Example 1 was laminated and then laminated. Thereafter, an adhesive LDPE layer, a tie resin layer, an ethylene vinyl alcohol (EVOH) resin layer, a tie resin layer, and an adhesive LDPE layer were sequentially coextruded and laminated. Next, a linear low-density polyethylene (LLDPE) resin film was laminated.

[0072] <Examples 2 to 4>

[0073] A packaging material was manufactured using the same method as Example 1 with the layer materials and thickness as shown in Table 1 below.

[0074]

[0075] <Comparative Examples 1 to 5>

[0076] A packaging material was manufactured using the same method as Example 1 with the layer materials and thickness as shown in Table 1 below.

[0077]

[0078]

[0079]

[0080] <Experimental Example 1> Mechanical properties

[0081] The mechanical properties of the specimens manufactured in the examples and comparative examples were evaluated in both MD and TD directions.

[0082] Tensile strength and elongation: Tensile strength (kgf / ㎠) and elongation (%) were measured for the specimens using the ASTM D638 method, and the results are shown in Table 2 below.

[0083] Tear strength: The tear strength was measured for the specimens using the ASTM D624 method, and the results are shown in Table 2 below.

[0084] Impact strength: The impact strength (Joule) of the specimens was measured using the ASTM D3420 method, and the results are shown in Table 2 below.

[0085] Interlayer peel strength: After applying adhesive or LDPE between the outer layer and the middle / inner layer and bonding them, the peel strength was measured after 10 minutes, and the results are shown in Table 2 below.

[0086]

[0087] <Experimental Example 2> Gas barrier properties

[0088] The gas barrier properties of the specimens manufactured in the examples and comparative examples were evaluated.

[0089] Oxygen barrier: Oxygen barrier was measured for the specimens using the ASTM D3985 method, and the results are shown in Table 2 below.

[0090] Vapor barrier properties: Vapor barrier properties were measured for the specimens using the ASTM F1249 method, and the results are shown in Table 2 below.

[0091]

[0092]

[0093]

[0094] As a result, as shown in Table 2 above, it can be seen that the mechanical properties and gas barrier properties of the specimens of Examples 1 to 4 are significantly improved compared to the specimens of Comparative Examples 1 to 5.

[0095] Accordingly, it was confirmed that the packaging material of the present invention can be used as a high-weight packaging material with excellent mechanical properties such as tensile strength, tear strength, impact strength, and elongation, and gas barrier properties.

Claims

1. An outer layer formed by forming an adhesive layer between multiple spiral cross-laminated films and laminating them; A middle layer formed on the outer layer and containing ethylene vinyl alcohol (EVOH) resin; and A packaging material formed on the above-mentioned multilayer and having an inner layer comprising linear low-density polyethylene (LLDPE) resin.

2. In paragraph 1, The above spiral cross-laminated film is a packaging material in which a cylindrical film manufactured by blown extrusion using high-density polyethylene (HDPE) resin is cut into a spiral shape, an adhesive resin of the same material is extrusion-coated on one sheet of the cut film, and then another sheet of the cut film is laminated so that the directional grains of the films intersect, thereby forming a film with directional grains in an alternating shape.

3. In paragraph 2, The above high-density polyethylene (HDPE) resin is a packaging material having a density of 0.940 to 0.970 g / cm3 and an MFR (190°C, 2.16 kgf) of 0.01 to 5 g / 10 min.

4. In paragraph 2, The above spiral cross-laminated film is a packaging material in which the above cylindrical film is cut at an angle of 22.5 to 67.5° to form a spiral shape.

5. In paragraph 1, A packaging material having a total thickness of the outer layer of 30 to 120㎛.

6. In paragraph 1, A packaging material wherein the adhesive layer comprises a low-density polyethylene (LDPE) resin.

7. In paragraph 6, The above low-density polyethylene (LDPE) resin is a packaging material having a density of 0.915 to 0.940 g / cm3 and an MFR (190°C, 2.16 kgf) of 3 to 10 g / 10 min.

8. In paragraph 1, A packaging material in which the above adhesive layer is T-die extrusion coated to a thickness of 5 to 20 μm.

9. In paragraph 1, Packaging material in which ozone treatment has been performed before formation of the above adhesive layer.

10. In paragraph 9, Packaging material in which the above ozone treatment is performed at a flow rate of 100 to 200 ml / min.

11. In paragraph 1, A packaging material having a structure in which the above-mentioned multilayer is sequentially laminated with an adhesive LDPE layer, a tie resin layer, an ethylene vinyl alcohol (EVOH) resin layer, a tie resin layer, and an adhesive LDPE layer.

12. In paragraph 11, A packaging material wherein the total thickness of the above-mentioned multilayer is 32 to 52 ㎛, the thickness of the adhesive LDPE layer is 10 to 20 ㎛, the thickness of the tie resin layer is 3 to 5 ㎛, and the thickness of the ethylene vinyl alcohol (EVOH) resin layer is 6 to 8 ㎛.

13. In paragraph 1, A packaging material having an ethylene vinyl alcohol (EVOH) resin content of 5% or less in the above-mentioned multilayer.

14. In paragraph 1, In the above-mentioned multilayer, ethylene vinyl alcohol (EVOH) resin is 27 to 44 mol% and has a density of 1.12 to 1.21 g / cm 3 And, packaging material having an MFR (190℃, 2.16kgf) of 1 to 8g / min.

15. In paragraph 1, The above linear low-density polyethylene (LLDPE) resin has a density of 0.870 to 0.940 g / cm 3 And, the packaging material has an MFR (190℃, 2.16kgf) of 1~5g / 10min.

16. In paragraph 1, A packaging material having an inner layer thickness of 30 to 80 μm and used as an ultra-low temperature sealing layer.

17. In paragraph 1, Packaging material used for packaging feed or food.

18. In paragraph 1, Packaging materials that can be recycled.

19. In paragraph 1, Packaging material available for packages weighing 3kg or more.

20. A step of cutting a cylindrical film manufactured by blown extrusion using high-density polyethylene (HDPE) resin at an angle of 22.5 to 67.5° to form a spiral shape, extrusion-coating an adhesive resin of the same material on one sheet of the cut film, and then laminating another sheet of the cut film so that the directional grains of the films intersect, thereby forming a spiral cross-laminated film having directional grains of an alternating shape; A step of forming an adhesive layer containing a low-density polyethylene (LDPE) resin between a plurality of the above spiral cross-laminated films and laminating them to form an outer layer; A step of forming a middle layer by sequentially laminating an adhesive LDPE layer, a tie resin layer, an ethylene vinyl alcohol (EVOH) resin layer, a tie resin layer, and an adhesive LDPE layer on the outer layer; and A method for manufacturing a packaging material, comprising the step of forming an inner layer comprising a linear low-density polyethylene (LLDPE) resin on the above-mentioned middle layer.

Images