JPH07304139A - Barrier packaging material and manufacturing method thereof - Google Patents

Abstract

PURPOSE:To provide a packing material which has appropriate gas barrier properties and is excellent from a view point of a cost and its manufacture. CONSTITUTION:A barrier film 2 containing an ethylene vinyl alcohol copolymer layer having a thickness of 3-12mum is coextruded and laminated on an oriented film on the rear of which a printed layer is formed and a sealant film 3 is extruded and laminated on the barrier film 2, through which a gas barrier packing material is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging material excellent in gas barrier property and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a packaging material having excellent gas barrier properties such as water vapor barrier property and oxygen barrier property (hereinafter referred to as barrier property packaging material), a laminate containing a metal foil or a metal vapor deposition layer has been formed. BACKGROUND ART A laminate including a plastic film is widely used and is molded (bag-formed) into a bag-shaped container for use. Aluminum is generally used as the metal in terms of performance, cost, and workability.

However, the above-mentioned metal foil or metal vapor deposition layer has a drawback that it becomes opaque when it has a thickness that exhibits gas barrier properties, and the contents cannot be seen through when used as a packaging material. Further, the metal foil becomes a lump in the furnace when incinerated, and there is a problem in disposability.

On the other hand, a resin layer such as an ethylene-vinyl alcohol copolymer or polyvinylidene chloride does not have the above problems and has a gas barrier property which is slightly inferior to that of a metal layer but can be practically used as a barrier material. Therefore, it is commonly used in the construction of barrier packaging materials. Further, the ethylene-vinyl alcohol copolymer is also known as a fragrance retaining material that does not allow fragrance components to pass therethrough.

This ethylene-vinyl alcohol copolymer is provided, for example, as a film having a thickness of 12 to 30 μm, and is dry-laminated with an adhesive or sand-laminated with a layer of a heat-adhesive resin melted. It is generally laminated with another film (for example, a base film or a sealant film) to form a part of the packaging material.

Polyvinylidene chloride is also used in a film form like the above-mentioned ethylene-vinyl alcohol copolymer, and a base film is coated with a solution dissolved in an appropriate solvent to form a thin layer, which is a barrier. It may also form a layer.

[0007]

However, since the above-mentioned polyvinylidene chloride contains chlorine as a component, when it is discarded after use, chlorine gas is generated when it is incinerated. In recent years, environmental protection has been called for, and the use of such resins is being shunned.

Further, since the ethylene-vinyl alcohol copolymer does not contain chlorine, environmental problems do not occur, but since it is generally used in a film state as described above, it is a dry material for packaging materials. A laminating process such as laminating 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. Then, the ethylene-vinyl alcohol copolymer resin itself is expensive, and as a result, the packaging material becomes expensive.

Also, the gas barrier property of the packaging material is proportional to the thickness of these resins within a certain range, so that depending on the required gas barrier property, ethylene-
The use of vinyl alcohol copolymer film was over-spec, costly and uneconomical.

Therefore, the present invention provides a barrier packaging material which has an appropriate (not excessively high) gas barrier property and is excellent in cost, and a method for producing the same.

[0011]

That is, the present invention is a packaging material in which a base film, a barrier film and a sealant film are sequentially laminated, and the barrier film is an ethylene-vinyl alcohol copolymer having a thickness of 3 to 12 μm. A barrier packaging material, which is a coextruded film containing a polymer layer.

The first method of producing a barrier packaging material of the present invention is to co-extrude and laminate a barrier film containing an ethylene-vinyl alcohol copolymer layer having a thickness of 3 to 12 μm on a base film. A method for producing a barrier packaging material, which comprises extruding and laminating a sealant film on the barrier film.

The second method of producing a barrier packaging material of the present invention is a barrier film containing an ethylene-vinyl alcohol copolymer layer having a thickness of 3 to 12 μm between a base film and a sealant film. Co-extrude,
A method for producing a barrier packaging material, which comprises sand-laminating the base film and the sealant film.

In the barrier packaging material of the present invention and the method for producing the same, it is preferable for the purpose of the present invention that a polyvinylidene chloride layer is not included in its constitution. Also,
The substrate film is preferably a stretched film, and when forming a printing layer, it is preferably formed on the surface of the substrate film on which the barrier film is laminated.

[0015]

The packaging material of the present invention having the above structure has a thickness of 3 in a barrier film made of a coextrusion film.
Includes an ethylene-vinyl alcohol copolymer layer of ˜12 μm, preferably 5-10 μm as a gas barrier layer.
Therefore, it is possible to impart a certain gas barrier property and a barrier property of the aroma component to the packaging material, and it is possible to reduce the amount of the expensive ethylene-vinyl alcohol copolymer resin used, so that the overall cost can be suppressed. it can.

Further, according to the method for producing a barrier packaging material of the present invention, the barrier film is co-extruded and laminated on the base film while it is in a molten state (that is, while thermal adhesiveness is exhibited). Therefore, a separate step of laminating the barrier film is not required, and the manufacturing cost of the packaging material can be suppressed.

The base film is a stretched film,
By forming a printing layer on the surface of the substrate film on which the barrier film is laminated, the printing layer is protected and the packaging material is suitable for packaging foods and the like. Furthermore, since the printing layer is formed on the smooth stretched film surface, the printing becomes beautiful.

[0018]

Embodiments of the present invention will now 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.

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, as shown in FIGS. , Thickness 3-12μ
m, preferably 5-10 μm ethylene-vinyl alcohol copolymer layer 4 is a co-extruded film.

The base film 1 is the main layer of the packaging material, and has a mechanical strength, tearability, slip property,
It gives the property of heat resistance. As a preferred material, a polyester film such as polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate, a polyamide film such as 6-nylon; 6,6-nylon, or a polypropylene film, which has excellent mechanical strength, can be used. . In particular, it is preferable to use these uniaxially or biaxially stretched films. If desired, well-known additives such as antistatic agents, slip agents, antifogging agents, and ultraviolet absorbers can be added to these films. If necessary, well-known treatments such as corona discharge treatment, ozone treatment, and flame treatment can be applied.

The thickness of the base film 1 is not particularly limited, but is preferably 12 to 40 μm.

The printing layer 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 in the figure.

The printing layer 5 can be formed by a conventional method, that is, a gravure printing method, a silk screen printing method, or any other known method.

If necessary, the base film 1 may be provided with an intervening layer or an outer layer not shown. For example, paper or a non-woven fabric (basis weight 1
5 to 90 g / m ² ) can be laminated.

A barrier film 2 is laminated on the base film 1. Barrier film 2 is a coextruded film containing a layer 4 of ethylene-vinyl alcohol copolymer. Specifically, the structure 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 structure of the polyolefin layer 7 (see FIG. 2) can be exemplified. In the barrier film 2, the ethylene-vinyl alcohol copolymer layer 4
For the purpose of the present invention, the thickness is 3 to 12 μm, preferably 5 to 10 μm.

When the thickness is larger than the above range, the amount of the resin used is not different as compared with the case where the ethylene-vinyl alcohol copolymer film is used, which is uneconomical and the gas barrier property may be excessive. On the other hand, when the thickness is less than the above range, the amount of the resin used is small, which is preferable, but it is difficult to obtain a continuous and uniform layer, and the desired gas barrier property may not be obtained.

Further, the adhesive resin layer 6 can be coextruded with the ethylene-vinyl alcohol copolymer layer 4 and is adjacent to the base film 1 and / or
Alternatively, a polyethylene-based adhesive resin (trade name: ADMER NF550, MODIC XM-40, which has good adhesion to the sealant film 3 or the polyolefin layer 7).
0M etc. and polypropylene adhesive resin (trade name: ADM
ER QF500 etc.) can be adopted. Particularly, when unstretched polypropylene is used as the sealant film 3, it is preferable to use the polypropylene adhesive resin as the adhesive resin layer 6. The thickness of this layer 6 is 3 to
The thickness is preferably 10 μm.

The polyolefin layer 7 (see FIG. 2) of the barrier film 2 is a low density polyethylene in consideration of coextrusion suitability with the ethylene-vinyl alcohol copolymer layer 4 and adhesiveness with the sealant film 3. It is preferable to use linear low density polyethylene. The thickness of the polyolefin layer 7 is preferably 10 to 30 μm.

If desired, well-known additives; for example, antistatic agents, slip agents, antifogging agents and the like can be added to each layer of the barrier film 2. If necessary, well-known treatments such as corona discharge treatment and ozone treatment,
Frame processing or the like can be performed. In particular, since the barrier film 2 (co-extrusion film) is laminated by extrusion lamination or sand lamination in the present invention as described below, the type of resin used for the base film 1, the barrier film 2 or the sealant film 3 Depending on the situation, the adhesion improving treatment such as corona discharge treatment or ozone treatment on the barrier film 2 is essential.

The overall thickness of the barrier film 2 is not particularly limited, but due to the nature of coextrusion, it is 10 to 50 μm.
The range of m is common.

Next, the sealant film 3 is a layer that imparts heat-sealing property 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). Resins such as can be used. In addition, a heat-sealable resin such as a heat-sealable polyester or an ethylene-vinyl alcohol copolymer may be used for a special purpose; As described below, this layer may be formed directly on the barrier film 2 by extrusion lamination,
Alternatively, a film state may be laminated.
Further, at the time of manufacturing the barrier film by the co-extrusion described above, the sealant film 3 is co-extruded at the same time,
You may make it integrated.

The thickness of this sealant film 3 is 10
˜100 μm, and particularly preferably 20 to 80 μm.

The above layers are laminated by extrusion laminating or sand laminating using the barrier film 2 as an adhesive layer.

The embodiment shown in FIG. 1 is obtained by co-extruding and laminating a barrier film 2 on a substrate film 1 and then extruding and laminating a sealant film 3 on the barrier film 2. In addition, in the embodiment shown in FIG. 2, a base film 1 and a sealant film 3 are prepared, and a barrier film 2 is co-extruded between the base film 1 and the sealant film 3 so that the base film 1 and the sealant film 3 are separated from each other. It was obtained by sand laminating. In addition, prior to these laminations, an anchor coating agent may be coated on the laminated surface, or the above-described pretreatment (corona treatment, ozone treatment, etc.) may be performed as necessary.

By applying the extrusion laminating or the sand laminating as described above, it is possible to omit the step for only adhering each layer, such as the dry laminating which has been widely used in the past, and thus reduce the cost of the entire packaging material. It is possible to do so, which is preferable.

Specific constitutional examples of the packaging material according to the present invention described above will be listed below. In the following, "EX" indicates a layer formed by extrusion lamination, and "[]"
The inner layer shows the layer by coextrusion. The number on the right shoulder is the thickness (μm).

(1) AS-OPP ³⁰ / mark / AC / [EVOH ⁵ / contact ⁵ / PE
¹⁵ ] / EX-AS-EVA ²⁵ (2) AS-OPP ³⁰ / mark / AC / [contact ⁵ / EVOH ⁵ / contact ⁵ ] / AS-EVA ⁴⁰ (3) OPP ²⁰ / mark / AC / [EVOH ⁵ / Connection 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 / Mark / 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 / mark / 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 / mark / 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 oriented polypropylene PET: Biaxially oriented polyethylene terephthalate NY: Oriented 6-nylon EVOH: Ethylene-vinyl alcohol copolymer layer Contact: Adhesive resin layer Mark: Printing layer AC: Anchor coat layer AS-: Antistatic agent kneading Inclusive

The above (1), (3), (4), (5), (7) and (9) are obtained by extruding and laminating a barrier film.
Further, (2), (6), (8) and (10) are obtained by laminating by sandwiching a barrier film (coextrusion film) between them. In addition, is the sealant film 3
(CPP) is coextruded at the same time when the barrier film 2 is manufactured.

The packaging material of the present invention obtained as described above is generally obtained by heat-sealing the sealant films 3 with each other, and a three-sided or four-sided sealing bag, a gusset bag, a standing pouch, a pillow packaging bag, etc. Used as. Further, the packaging material of the present invention can be punched into an appropriate shape and used as a heat-seal lid for a container. The packaging material of the present invention can also be used as a body member of a tube container.

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, discoloration and discoloration due to oxidation, decay due to the growth of microorganisms, prevention of the development of mold, etc., further required aroma retention, shavings, pickles, boiled sweets, snacks, beans It is suitable for packaging foods such as confectionery, castella, steamed buns, miso, dried noodles, pet food, ham / sausage, butter, cheese and rice cake.

Example 1 A printing layer was formed on a biaxially oriented polypropylene film having a thickness of 30 μm with an ink containing a polyurethane resin as a vehicle. Anchor coating agent containing polyurethane resin as a main component is applied on the printed layer 9 times.
The coating amount was g / m ² . An ethylene-vinyl alcohol copolymer layer (10 μm) / adhesive resin layer (polyethylene-based; MO;
A coextrusion film (barrier film) having a constitution of DIC XM-400M: 5 μm) / low density polyethylene (20 μm) was extrusion 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.

The barrier property of the obtained packaging material was measured.
However, the oxygen permeability is 0.5cc / m ²・ 24hrs ・ atm,
Water vapor permeability is 4g / m²・ It was 24hrs. Also, the mark
The printing was very beautiful.

Example 2 A printing layer was formed on a biaxially stretched polypropylene film having a thickness of 30 μm with an ink containing a polyurethane resin as a vehicle. Anchor coating agent consisting mainly of polyurethane resin is applied on this printed layer.
The coating amount was g / m ² . Between the printed layer surface of this biaxially oriented polypropylene film and the linear low-density polyethylene (sealant film) having a thickness of 30 μm, 3 types 3
By a layer co-extruder, an adhesive resin layer (polyethylene type; MODIC XM-400M: 5 μm) / ethylene-vinyl alcohol copolymer layer (10 μm) / adhesive resin layer (polyethylene type; MODIC XM-400M:
A coextrusion film (barrier film) having a constitution of 5 μm) was extruded and laminated by sand lamination to obtain a barrier packaging material of the present invention.

The barrier property of the obtained packaging material was measured.
However, the oxygen permeability is 0.5cc / m ²・ 24hrs ・ atm,
Water vapor permeability is 4g / m²・ It was 24hrs.

[0045]

As described above, in the barrier packaging material of the present invention, since the expensive ethylene-vinyl alcohol copolymer is used as the co-extrusion film, the layer can be made thin,
The cost can be reduced. Further, according to the manufacturing method of the present invention, the process for simple lamination can be omitted, and the manufacturing cost can be suppressed.

Further, according to the present invention, the thickness of the ethylene-vinyl alcohol copolymer layer as the barrier layer can be easily changed to an arbitrary thickness, and the gas barrier property can be adjusted arbitrarily.

Further, since the obtained packaging material has appropriate gas barrier property and fragrance retaining property, it is an environmentally friendly alternative to the packaging material having a coating layer of polyvinylidene chloride as a barrier layer so far. It can be used as a material. In addition, the packaging material of the present invention is a substitute material having an appropriate gas barrier property in place of a material having a gas barrier property that is too high because it has an ethylene-vinyl alcohol copolymer film as a barrier layer so far. Can be used as

When the printing layer is formed on the inner surface (back surface) side of the substrate film, it has excellent printing effect and beauty.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example 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]

 1 ... Substrate film 2 ... Barrier film 3 ... Sealant film 4 ... Ethylene-vinyl alcohol copolymer 5 ... Printing layer 6 ... Adhesive resin 7 ... Polyolefin

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B29L 9:00

Claims (14)

[Claims] 1. A packaging material in which a base film, a barrier film, and a sealant film are sequentially laminated, wherein the barrier film is a co-extruded film containing an ethylene-vinyl alcohol copolymer layer having a thickness of 3 to 12 μm. A barrier packaging material characterized by being present. 2. The ethylene-vinyl alcohol copolymer layer has a thickness of 5 to 10 μm.
The barrier packaging material according to. 3. A barrier packaging material according to claim 1, characterized in that it does not contain a polyvinylidene chloride layer in its construction. 4. The printed film is formed on the surface of the base film, which is a stretched film, to be laminated on the barrier film of the base film, and the printed layer is formed. The barrier packaging material according to. 5. The barrier film according to any one of claims 1 to 4, wherein the barrier film has a constitution of adhesive resin layer / ethylene-vinyl alcohol copolymer layer / adhesive resin layer. Barrier packaging material. 6. The barrier film has a constitution of ethylene-vinyl alcohol copolymer layer / adhesive resin layer / polyolefin layer, and the ethylene-vinyl alcohol copolymer layer side of the barrier film faces the base film. The barrier packaging material according to any one of claims 1 to 4, which is laminated. 7. A barrier film containing an ethylene-vinyl alcohol copolymer layer having a thickness of 3 to 12 μm is co-extruded and laminated on a base film, and a sealant film is extruded and laminated on the barrier film. A method for producing a barrier packaging material. 8. The barrier packaging material according to claim 7, wherein the base film is a stretched film, and a printing layer is formed on the surface of the base film to be laminated on the barrier film. Manufacturing method. 9. The barrier film according to claim 7, wherein the barrier film has a constitution of adhesive resin layer / ethylene-vinyl alcohol copolymer layer / adhesive resin layer. Method for manufacturing barrier packaging material. 10. The barrier film has a constitution of ethylene-vinyl alcohol copolymer layer / adhesive resin layer / polyolefin layer, and the ethylene-vinyl alcohol copolymer layer side of the barrier film faces the base film. Claim 7 or Claim 8 characterized by being laminated.
A method for producing a barrier packaging material according to any one of 1. 11. A barrier film containing an ethylene-vinyl alcohol copolymer layer having a thickness of 3 to 12 μm is coextruded between a substrate film and a sealant film,
A method for producing a barrier packaging material, which comprises sand-laminating the base film and the sealant film. 12. The barrier packaging material according to claim 11, wherein the base film is a stretched film, and a printing layer is formed on the surface of the base film to be laminated on the barrier film. Manufacturing method. 13. The barrier film according to claim 11, wherein the barrier film has a constitution of adhesive resin layer / ethylene-vinyl alcohol copolymer layer / adhesive resin layer. Method for manufacturing barrier packaging material. 14. The barrier film has a constitution of ethylene-vinyl alcohol copolymer layer / adhesive resin layer / polyolefin layer, and the ethylene-vinyl alcohol copolymer layer side of the barrier film faces the base film. The method for producing a barrier packaging material according to claim 11 or 12, wherein the barrier packaging material is laminated.