JP3836164B2 - Barrier packaging material and method for producing the same - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a packaging material excellent in gas barrier properties and a method for producing the same.
[0002]
[Prior art]
Conventionally, as a packaging material excellent in gas barrier properties such as water vapor barrier property and oxygen barrier property (hereinafter referred to as barrier packaging material), a laminate including a laminate including a metal foil or a plastic film having a metal vapor-deposited layer formed thereon. The body is widely used, and is molded (made into a bag) into a bag-like container. And as said metal, aluminum is generally used from the point of performance, cost, and workability.
[0003]
However, the metal foil and the metal vapor-deposited layer are opaque when the thickness exhibits gas barrier properties, and the contents cannot be seen through when used as a packaging material. In addition, when the metal foil is incinerated, it becomes a lump in the furnace, and there is a problem in discardability.
[0004]
On the other hand, resin layers such as ethylene-vinyl alcohol copolymer and polyvinylidene chloride do not have the above-mentioned problems, and the gas barrier property is slightly inferior to that of the metal layer, but can be practically used as a barrier material. Commonly used in the construction of adhesive packaging materials. Furthermore, the ethylene-vinyl alcohol copolymer is also known as an aroma retaining material that does not allow permeation of aroma components.
[0005]
This ethylene-vinyl alcohol copolymer is provided, for example, as a film having a thickness of 12 to 30 μm, and other films can be obtained by dry lamination using an adhesive or by sand lamination via a molten layer of a heat-adhesive resin. It is generally laminated with (for example, a base film or a sealant film) to constitute a part of the packaging material.
[0006]
Polyvinylidene chloride is also used in the same film form as the ethylene-vinyl alcohol copolymer, and a thin film is formed by coating a base film with a solution dissolved in an appropriate solvent to form a barrier layer. Sometimes.
[0007]
[Problems to be solved by the invention]
However, since the polyvinylidene chloride contains chlorine in its components, chlorine gas is generated when incinerated when discarded after use. In recent years, environmental protection has been screamed, and the use of such resins is being avoided.
[0008]
In addition, since ethylene-vinyl alcohol copolymer does not contain chlorine, it does not cause environmental problems. However, since it is generally used in a film state as described above, a dry laminate or the like is used as a packaging material. A lamination process is essential. Further, since the material is supplied in a film state, there is a lower limit of the thickness, and usually 12 μm is the lower limit. And ethylene-vinyl alcohol copolymer resin itself is expensive, and as a result, the packaging material becomes expensive.
[0009]
In addition, since the gas barrier property of the packaging material is proportional to the thickness of these resins within a certain range, depending on the required gas barrier property, the use of the ethylene-vinyl alcohol copolymer film is overspec. It was expensive and uneconomical.
[0010]
Therefore, the present invention provides a barrier packaging material having an appropriate (not excessively high) gas barrier property and excellent in cost, and a method for producing the same.
[0011]
[Means for Solving the Problems]
[0012]
A first method for producing a barrier packaging material according to the present invention is a method of coextruding a barrier film containing an ethylene-vinyl alcohol copolymer layer having a thickness of 3 to 12 μm on a base film and laminating the barrier film on the barrier film. A method for producing a barrier packaging material, wherein a sealant film is extruded and laminated .
[0013]
In the second method for producing a barrier packaging material of the present invention, a barrier film containing an ethylene-vinyl alcohol copolymer layer having a thickness of 3 to 12 μm is coextruded between a base film and a sealant film. A method for producing a barrier packaging material , wherein the substrate film and the sealant film are sand-laminated .
[0014]
In the barrier packaging material and the method for producing the same of the present invention, it is preferable from the object of the present invention that the polyvinylidene chloride layer is not included in the constitution.
Moreover, it is preferable that a base film is a stretched film, and when forming a printing layer, it is preferable to form in the surface where the barrier film of the said base film is laminated | stacked.
[0015]
[Action]
The packaging material of the present invention having the above-described configuration includes an ethylene-vinyl alcohol copolymer layer having a thickness of 3 to 12 μm, preferably 5 to 10 μm, as a gas barrier layer in a barrier film made of a coextruded film. Therefore, it is possible to impart a certain gas barrier property and fragrance component barrier property to the packaging material, and to reduce the amount of expensive ethylene-vinyl alcohol copolymer resin used, thereby reducing the overall cost. it can.
[0016]
Further, according to the method for producing a barrier packaging material of the present invention, the barrier film is coextruded and laminated on the base film while it is in a molten state (that is, while thermal adhesiveness is exerted) A separate process for laminating the barrier film becomes unnecessary, and the manufacturing cost of the packaging material can be reduced.
[0017]
In addition, by forming a base film as a stretched film and forming a print layer on the surface of the base film on which the barrier film is laminated, the print layer is protected and a packaging material suitable for packaging foods and the like is obtained. Further, since the printing layer is formed on the smooth stretched film surface, the printing becomes beautiful.
[0018]
【Example】
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the packaging material of the present invention, and FIG. 2 is a sectional view showing another embodiment of the packaging material of the present invention.
[0019]
As shown in FIGS. 1 and 2, the barrier packaging material of the present invention is a packaging material in which a base film 1, a barrier film 2, and a sealant film 3 are sequentially laminated, and the barrier film 2 has a thickness. A coextruded film comprising an ethylene-vinyl alcohol copolymer layer 4 of 3 to 12 μm, preferably 5 to 10 μm.
[0020]
The base film 1 is a main layer of the packaging material, and gives the packaging material properties such as mechanical strength, tear properties, slip properties, and heat resistance. As a preferable material, a material excellent in mechanical strength such as a polyester film such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, 6-nylon; a polyamide film such as 6,6-nylon, or a polypropylene film can be used. . In particular, it is preferable to use these uniaxially or biaxially stretched films. Moreover, well-known additives; for example, an antistatic agent, a slip agent, an antifogging agent, an ultraviolet absorber, etc. can be added to these films as needed. Moreover, a well-known process; for example, a corona discharge process, an ozone process, a flame process etc. can be performed as needed.
[0021]
The thickness of the base film 1 is not particularly limited, but is preferably 12 to 40 μm.
[0022]
The printing material 5 is usually formed on the packaging material, but it is preferably formed on the surface of the base film 1 on which the barrier film 2 is laminated, as shown.
[0023]
The printing layer 5 can be formed by a normal method, that is, a gravure printing method, a silk screen printing method, or other known methods.
[0024]
Moreover, you may form the intervening layer and outer layer which are not shown in figure in the base film 1 as needed. For example, paper or a nonwoven fabric (basis weight 15-90 g / m < ² >) can be laminated | stacked on the outer surface side or inner surface side of the base film 1 for the purpose of provision of a texture or rigidity.
[0025]
A barrier film 2 is laminated on the base film 1. The barrier film 2 is a coextruded film comprising a layer 4 of ethylene-vinyl alcohol copolymer. Specifically, the configuration of adhesive resin layer 6 / ethylene-vinyl alcohol copolymer layer 4 / adhesive resin layer 6 (see FIG. 1), or ethylene-vinyl alcohol copolymer layer 4 / adhesive resin layer 6 / The configuration of the polyolefin layer 7 (see FIG. 2) can be exemplified. In the barrier film 2, the thickness of the ethylene-vinyl alcohol copolymer layer 4 is 3 to 12 μm, preferably 5 to 10 μm for the purpose of the present invention.
[0026]
When the thickness is larger than the above range, there is no difference in the amount of resin used compared to the case of using an ethylene-vinyl alcohol copolymer film, which is uneconomical and may have an excessive gas barrier property. On the other hand, when the thickness is smaller than the above range, it is preferable because the amount of the resin used is small, but it is difficult to obtain a continuous and uniform layer, and the target gas barrier property may not be obtained.
[0027]
The adhesive resin layer 6 can be co-extruded with the ethylene-vinyl alcohol copolymer layer 4 and is adjacent to the base film 1 and / or the sealant film 3 or the polyolefin layer 7. A polyethylene-based adhesive resin (trade name: ADMER NF550, MODIC XM-400M, etc.) or a polypropylene adhesive resin (trade name: ADMER QF500, etc.) having good adhesion can be used. In particular, when unstretched polypropylene is employed as the sealant film 3, it is preferable to employ the polypropylene adhesive resin as the adhesive resin layer 6. The thickness of this layer 6 is preferably 3 to 10 μm.
[0028]
The polyolefin film 7 of the barrier film 2 (see FIG. 2) is a low-density polyethylene, linear, considering coextrusion suitability with the ethylene-vinyl alcohol copolymer layer 4 and adhesiveness with the sealant film 3. Low density polyethylene is preferred. The thickness of the polyolefin layer 7 is preferably 10 to 30 μm.
[0029]
A known additive; for example, an antistatic agent, a slip agent, an antifogging agent, or the like can be added to each layer of the barrier film 2 as necessary. Moreover, a well-known process; for example, a corona discharge process, an ozone process, a flame process etc. can be performed as needed. In particular, since the barrier film 2 (coextruded film) is laminated by extrusion lamination or sand lamination in the present invention as will be described later, the kind of resin used for the base film 1, the barrier film 2, or the sealant film 3 Depending on the case, the barrier film 2 must be subjected to an adhesive improvement treatment such as corona discharge treatment or ozone treatment.
[0030]
The overall thickness of the barrier film 2 is not particularly limited, but is generally in the range of 10 to 50 μm because of the coextrusion property.
[0031]
Next, the sealant film 3 is a layer that imparts heat sealability to the packaging material, and a commonly used material can be used.
Specifically, low density polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer, unstretched polypropylene, ionomer, ethylene-acrylic acid copolymer (EAA), ethylene-methacrylic acid copolymer (EMAA) Etc. can be used. In addition, for special purposes; for example, in the case of aroma retention, a heat-sealable resin such as a heat-sealable polyester or an ethylene-vinyl alcohol copolymer may also be used. As will be described later, this layer may be formed directly on the barrier film 2 by extrusion lamination, or may be laminated in a film state. Further, when the barrier film is manufactured by the co-extrusion described above, the sealant film 3 may be co-extruded at the same time and integrated.
[0032]
The thickness of the sealant film 3 is preferably 10 to 100 μm, more preferably 20 to 80 μm.
[0033]
Each of the above layers is laminated by extrusion lamination or sand lamination using the barrier film 2 as an adhesive layer.
[0034]
The example shown in FIG. 1 is obtained by coextrusion laminating a barrier film 2 on a base film 1 and extruding and laminating a sealant film 3 on the barrier film 2. In the embodiment shown in FIG. 2, a base film 1 and a sealant film 3 are prepared, and the barrier film 2 is coextruded between the two, whereby the base film 1 and the sealant film 3 are combined. It was obtained by sand lamination. Prior to these laminations, the laminated surface can be coated with an anchor coating agent, or pretreatment as described above (corona treatment, ozone treatment, etc.) can be performed as necessary.
[0035]
By applying an extrusion laminate or a sand laminate as described above, it is possible to omit a process only for bonding each layer, such as a dry laminate, which has been widely performed in the past, and thus the cost of the entire packaging material can be reduced. preferable.
[0036]
Specific configuration examples of the packaging material according to the present invention described above are listed below. In the following, “EX” indicates a layer formed by extrusion lamination, and a layer in “[]” indicates a layer formed by co-extrusion. The number on the right shoulder is the thickness (μm).
[0037]
(1) AS-OPP ³⁰ / mark / AC / [EVOH ⁵ / contact ⁵ / PE ¹⁵ ] / EX-AS-EVA ²⁵
(2) AS-OPP ³⁰ / indicia / AC / [contact ⁵ / EVOH ⁵ / contact ^5] / AS-EVA ⁴⁰
(3) OPP ²⁰ / mark / AC / [EVOH ⁵ / contact ³ / PE ²⁰ ] / EX-EVA ³⁰
(4) OPP ²⁵ / mark / AC / [EVOH ¹⁰ / contact ⁵ / PE ²⁰ ] / EX-EVA ³⁰
(5) OPP ²⁵ / mark / AC / [EVOH ¹⁰ / contact ⁵ / CPP ³⁰ ]
(6) OPP ²⁰ / indicia / AC / [contact ⁵ / EVOH ⁵ / contact ^5] / CPP ⁴⁰
(7) PET ¹² / mark / AC / [EVOH ⁵ / contact ⁵ / LLDPE ²⁰ ] / EX-LLDPE ³⁰
(8) PET ¹² / indicia / AC / [contact ⁵ / EVOH ⁵ / contact ^5] / CPP ⁴⁰
(9) NY ¹⁵ / mark / AC / [EVOH ⁵ / contact ⁵ / PE ²⁰ ] / EX-LLDPE ³⁰
(10) NY ¹⁵ / indicia / AC / [contact ⁵ / EVOH ⁵ / contact ^5] / LLDPE ⁵⁰
PE: low density polyethylene LLDPE: linear low density polyethylene EVA: ethylene-vinyl acetate copolymer CPP: unstretched polypropylene OPP: biaxially stretched polypropylene PET: biaxially stretched polyethylene terephthalate NY: stretched 6-nylon EVOH: ethylene-vinyl Alcohol copolymer layer contact: adhesive resin layer mark: printed layer AC: anchor coat layer AS-: kneaded antistatic agent
The above (1), (3), (4), (5), (7), and (9) are obtained by laminating barrier films by extrusion lamination. Also, (2), (6), (8), and (10) are obtained by laminating by a sand laminate with a barrier film (coextruded film) sandwiched therebetween. In addition, (5) is obtained by coextruding the sealant film 3 (CPP) at the same time when the barrier film 2 is manufactured.
[0039]
The packaging material of the present invention obtained as described above is generally used as a three- or four-side sealed bag, a gusset bag, a standing pouch, a pillow packaging bag, etc. by heat sealing the sealant films 3 to each other. The Further, the packaging material of the present invention can be appropriately punched into a shape and used as a heat seal lid for a container. Moreover, the packaging material of this invention can also be used as a trunk | drum member of a tube container.
[0040]
The packaging material of the present invention exhibits barrier properties such as an oxygen permeability of 0.3 to 2.0 cc / m ² · 24 hrs · atm and a water vapor permeability of ² to 10 g / m ² · 24 hrs. Therefore, the packaging material of the present invention is required to have a discoloration and taste due to oxidation, spoilage due to the propagation of microorganisms, generation of spider, etc., and further to maintain aroma, etc., shaving, pickles, boiled, snacks, beans It is suitable for packaging foods such as confectionery, castella, buns, miso, dried noodles, pet food, ham / sausage, butter, cheese, and candy.
[0041]
<Example 1>
A printing layer was formed on a biaxially stretched polypropylene film having a thickness of 30 μm with an ink using a polyurethane-based resin as a vehicle. On this printed layer, an anchor coating agent mainly composed of a polyurethane resin was applied at an application amount of 9 g / m ² . On top of this, the composition of ethylene-vinyl alcohol copolymer layer (10 μm) / adhesive resin layer (polyethylene type; MODIC XM-400M: 5 μm) / low density polyethylene (20 μm) was formed by a three-type three-layer coextrusion machine. A coextruded film (barrier film) was extruded and laminated. Further, a linear low density polyethylene (sealant film) having a thickness of 30 μm was laminated on the low density polyethylene by extrusion lamination to obtain a barrier packaging material of the present invention.
[0042]
When the barrier property of the obtained packaging material was measured, the oxygen permeability was 0.5 cc / m ² · 24 hrs · atm, and the water vapor permeability was 4 g / m ² · 24 hrs.
Also, the printing was very beautiful.
[0043]
<Example 2>
A printing layer was formed on a biaxially stretched polypropylene film having a thickness of 30 μm with an ink using a polyurethane-based resin as a vehicle. On this printed layer, an anchor coating agent mainly composed of a polyurethane resin was applied at a coating amount of 4 g / m ² . An adhesive resin layer (polyethylene-based; MODIC XM-400M) is formed between the printed layer surface of the biaxially oriented polypropylene film and a linear low-density polyethylene (sealant film) having a thickness of 30 μm by a three-type three-layer coextrusion machine. : 5 μm) / ethylene-vinyl alcohol copolymer layer (10 μm) / adhesive resin layer (polyethylene type; MODIC XM-400M: 5 μm), a co-extruded film (barrier film) is extruded and laminated by sand lamination, The barrier packaging material of the present invention was obtained.
[0044]
When the barrier property of the obtained packaging material was measured, the oxygen permeability was 0.5 cc / m ² · 24 hrs · atm, and the water vapor permeability was 4 g / m ² · 24 hrs.
[0045]
【The invention's effect】
As described above, since the barrier packaging material of the present invention uses an expensive ethylene-vinyl alcohol copolymer as a coextruded film, the layer can be thinned and the cost can be reduced. Moreover, according to the manufacturing method of this invention, the process for mere lamination | stacking can be abbreviate | omitted and manufacturing cost can be held down.
[0046]
And according to this invention, the thickness of the ethylene-vinyl alcohol copolymer layer as a barrier layer can be easily changed into arbitrary thickness, and gas barrier property can be adjusted arbitrarily.
[0047]
In addition, since the obtained packaging material has appropriate gas barrier properties and fragrance retention properties, it can be used as an environmentally friendly alternative to packaging materials that previously had a polyvinylidene chloride coating layer as a barrier layer. can do. In addition, the packaging material of the present invention is an alternative material having an appropriate gas barrier property instead of a material that has had an ethylene-vinyl alcohol copolymer film as a barrier layer so far that the gas barrier property is too high. Can be used as
[0048]
And when a printing layer is formed in the inner surface (back surface) side of a base film, it has the outstanding printing effect and beauty.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a packaging material of the present invention.
FIG. 2 is a cross-sectional view showing another embodiment of the packaging material of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Base film 2 ... Barrier film 3 ... Sealant film 4 ... Ethylene-vinyl alcohol copolymer 5 ... Printing layer 6 ... Adhesive resin 7 ... Polyolefin

Claims (6)

Thick 3~12μm ethylene - a barrier film obtained by laminating a polyethylene-based adhesive resin or polypropylene based adhesive resin to both surfaces of the vinyl alcohol copolymer layer and laminate-Shi pushed out co, laminated on a base film the method of barrier packaging material characterized by laminating and out Shi laminate-pressing sealant film contacting adhesive resin layer Bas rear film. Thick 3~12μm ethylene - a barrier film is the configuration of the vinyl alcohol copolymer layer / polyethylene-based adhesive resin or polypropylene-based adhesive resins layers / polyolefin resin layer, and coextrusion laminating an ethylene - vinyl alcohol copolymer as the polymer layer surface facing the base film, barrier wrap, characterized in that laminated on a base film, laminating and out Shi laminate-pressing sealant film to the polyolefin resin layer Bas rear film Material manufacturing method. Between the base film and sealant film, an ethylene thick 3 to 12 [mu] m - Shi pushed out co barrier film obtained by laminating a polyethylene-based adhesive resin or polypropylene based adhesive resin layer on both surfaces of the vinyl alcohol copolymer layer to method for producing a barrier packaging material, characterized in that the sand laminated between the base film and the sealant film. Between the base film and sealant film, an ethylene thick 3 to 12 [mu] m - a barrier film is a vinyl alcohol copolymer layer / polyethylene-based adhesive resin or polypropylene-based adhesive resins layers / polyolefin resin layer structure , ethylene - barrier packaging material, characterized in that the sand laminated between the vinyl to be lion pushed out co as alcohol copolymer layer surface is laminated facing the base film, the base film and sealant film Manufacturing method. Claims 1 to said substrate film A method of manufacturing a barrier packaging material according to any one of 4, polyethylene terephthalate, polybutylene terephthalate, polyester film such as polyethylene naphthalate, 6-nylon, 6,6 -A method for producing a barrier packaging material, characterized in that it is a stretched film of any one of a polyamide film such as nylon and a polypropylene film, and a printed layer is formed on the surface of the base film on which the barrier film is laminated. . The method for producing a barrier packaging material according to any one of claims 1 to 5 , wherein the sealant film is low density polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer, unstretched polypropylene, ionomer. A barrier packaging material characterized by being a film made of any one resin of ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, heat- sealable polyester, and ethylene-vinyl alcohol copolymer Manufacturing method.

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