JP2002192675A - Packaging material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate packaging material containing no adhesive layer between an intermediate plastic film of the multi-layered packaging material and a sealant layer, thereby showing no component eluting to the surface of the sealant layer resulting from the adhesive and capable of being manufactured in good efficiency. SOLUTION: A laminate comprises a base material 1, a gas barrier layer 3, a polyester film 4 and a sealant layer 10 wherein the sealant layer 10 is an adhesive resin layer 5 extruded at a resin temperature of not lower than 300 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging material having a multilayer structure, which has a small amount of various components eluted from an adhesive on the inner surface and has high production efficiency.

[0002]

2. Description of the Related Art Hitherto, in the field of packaging, as a packaging material having excellent gas barrier properties, a packaging material having a multilayer structure in which a gas barrier layer, a plastic film, and a sealant layer are sequentially laminated on one surface of a substrate has been used. In these packaging materials, a method of laminating a plastic film and a sealant layer has been performed by a dry lamination method or a polyethylene sand lamination method via an adhesive layer made of a polyurethane adhesive or the like.

[0003]

However, in these laminating methods, components in the adhesive used for the adhesive layer are eluted on the surface of the sealant layer, which adversely affects the taste or hygiene of the contents. Or a drying step to remove the solvent after applying the adhesive, and a step of aging for about 48 hours at a temperature of about 50 ° C. to increase the reaction rate of the components in the adhesive, etc. There was a problem.

[0004] An object of the present invention is to solve these problems by providing a package made of a laminated body having no production components caused by an adhesive on the surface of a sealant layer of a multi-layered packaging material and having high production efficiency. It is to provide materials.

[0005]

The invention according to claim 1 of the present invention comprises a substrate, a gas barrier layer, a polyester film,
A packaging material characterized in that in a laminate comprising a sealant layer, the sealant layer comprises an adhesive resin extruded at a resin temperature of 300 ° C. or higher.

[0006] Next, a second aspect of the present invention is to provide a laminate comprising a base material, a gas barrier layer, a polyester film, and a sealant layer, wherein the sealant layer is formed of a coextruded adhesive resin at a resin temperature of 300 ° C or higher. A packaging material comprising a high density polyethylene resin.

Next, a third aspect of the present invention is to provide a laminate comprising a base material, a gas barrier layer, a polyester film and a sealant layer, wherein the sealant layer is extruded at a resin temperature of 300 ° C. or higher into a polyolefin-based adhesive resin. A packaging material comprising a laminate of films.

Next, according to a fourth aspect of the present invention, in the first aspect of the present invention, the surface of the polyester film on the sealant layer side is surface-treated by a corona treatment method. Packaging material.

Next, according to a fifth aspect of the present invention, in the first aspect of the present invention, the adhesive resin has a density of 0.850 to 0.910 g / cm ^3.
A packaging material comprising a linear low-density polyethylene resin.

Next, the invention according to claim 6 is the invention according to any one of claims 1 to 4, wherein the adhesive resin is an ethylene / (meth) acrylic acid copolymer,・ For (meth) acrylic acid / (meth) acrylate copolymer, ethylene / (meth) acrylate copolymer, polyethylene or linear low density polyethylene or low crystalline ethylene / α-olefin copolymer A packaging material comprising any one of resins to which epoxidized soybean oil is added.

[0011]

According to the present invention, when laminating the polyester film 4 and the sealant layer 10 in the middle of the lamination structure, the surface of the polyester film 4 on the sealant layer 10 side is corona-coated without using a conventional adhesive or anchoring agent. Since the adhesive resin 5 extruded at a resin temperature of 300 ° C. or more is laminated on the treated surface, the adhesive component is not eluted on the surface of the sealant layer 10 in contact with the contents.
In addition, since the sealant layer 10 is laminated in one step, manufacturing efficiency is improved.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The packaging material of the present invention will be described below in detail according to embodiments.

FIG. 1 is a side sectional view showing an embodiment of the present invention, in which a substrate 1, an adhesive layer 2, a gas barrier layer 3, a polyester film 4, and an adhesive resin 5 are sequentially laminated in the thickness direction. According to the present invention, since the adhesive resin 5 is extruded and laminated on the corona-treated surface 20 of the polyester film 4 at a resin temperature of 300 ° C. or more, the adhesive strength to the polyester film 4 is high. It is not necessary to use a system-based adhesive or the like, and since the adhesive resin 5 has a heat sealing property, it is also characterized in that it also serves as the sealant layer 10. FIG. 2 is a side sectional view showing another embodiment of the present invention, and shows a substrate 1, an adhesive layer 2, a gas barrier layer 3, a polyester film 4,
The adhesive resin 5 and the low-density polyethylene resin 6 are sequentially laminated. In the present invention, after the two layers of the adhesive resin 5 and the low-density polyethylene resin 6 are laminated in advance in a melt extruder, the adhesive The corona-treated surface 20 of the polyester film 4 so that the resin 5 is on the polyester film 4 side.
Since it is laminated by a co-extrusion method that is directly extruded to the polyester film, the adhesive strength to the polyester film 4 is strong, so that a conventional polyurethane-based adhesive or the like is not required, and since it is laminated in a single step, it is manufactured. It has features such as high efficiency. FIG. 3 is a side sectional view showing another embodiment of the present invention, and shows a substrate 1, an adhesive layer 2, a gas barrier layer 3, a polyester film 4, an adhesive resin 5, and a polyolefin-based film 7 in the order of thickness. In the present invention, the adhesive resin 5 is laminated by a sandwich lamination method in which the adhesive resin 5 is extruded and sandwiched between the corona treated surface 20 of the polyester film 4 and the polyolefin film 7 at a resin temperature of 300 ° C. or more. Therefore, the adhesive strength to the polyester film 4 is strong, so that there is no need for a conventional polyurethane-based adhesive or the like, and since it is laminated in a single process, there is a feature that the production efficiency is good.

The base material 1 includes paperboard, biaxially oriented polypropylene film (hereinafter referred to as OPP film), biaxially oriented polyester film (hereinafter referred to as PET film), biaxially oriented nylon film (hereinafter referred to as ONY film), Other films are available.

As the gas barrier layer 3, an aluminum foil, a laminated film of an aluminum foil and a PET film,
PET film on which an inorganic compound such as aluminum or aluminum oxide or silicon oxide is deposited, ethylene
A laminated film of vinyl alcohol film and PET film can be used, and the thickness of aluminum foil is 6
The thickness of the PET film is preferably in the range of 6 to 12 μm, and the thickness of the ethylene / vinyl alcohol film is preferably in the range of 6 to 20 μm.

The method of laminating the substrate 1 and the gas barrier layer 3 includes a wet lamination method in which an emulsion-type adhesive is applied as the adhesive layer 2 on the substrate 1 and bonded to the gas barrier layer 3. A dry lamination method in which a polyurethane-based adhesive or the like is applied as the adhesive layer 2 and bonded to the gas barrier layer 3, or a thermoplastic resin is extruded and bonded as the adhesive layer 2 between the base material 1 and the gas barrier layer 3. Although lamination can be performed by a sand lamination method or the like, the present invention is not particularly limited.

The polyester film 4 is preferably a biaxially stretched polyester film having a thickness of 6 to 12 μm. The surface of the polyester film 4 on the sealant layer 10 side is preferably subjected to a surface treatment by a corona treatment or the like in order to improve the adhesive strength.

The adhesive resin 5 is made of ethylene.
(Meth) acrylic acid copolymer, ethylene / (meth) acrylic acid / (meth) acrylic acid ester copolymer, ethylene / (meth) acrylic acid ester copolymer, ethylene / (meth) acrylic Resin mixed with an acid copolymer, linear low-density polyethylene resin having a density of 0.850 to 0.910 g / cm ³ , polyethylene or linear low-density polyethylene, or low-crystalline ethylene / α-olefin copolymer And a resin obtained by adding epoxidized soybean oil to the above.

Incidentally, (meth) acrylic acid means acrylic acid or methacrylic acid, and (meth) acrylic acid ester means acrylic acid ester or methacrylic acid ester. (Meth) acrylic acid esters include methyl, ethyl, n-butyl, isobutyl, 2-ethylhexyl,
Esters such as isooctyl can be mentioned.

The method of laminating the adhesive resin 5 includes a method of extruding the adhesive resin 5 in a single layer onto the corona-treated surface 20 of the polyester film 4 by a melt extruder as described above, and a method of previously adhering the adhesive resin in the melt extruder. A co-extrusion method in which the resin 5 and the low-density polyethylene resin 6 are laminated and extruded onto the corona-treated surface 20 of the polyester film 4 can be used. At this time, the resin temperature at the time of extrusion is preferably 300 ° C. or more. If the temperature of the extruded resin is lower than 300 ° C., the adhesive strength to the polyester film 4 becomes weak, which is not good.

The resin used for the polyolefin film 7 includes low-density polyethylene resin, medium-density polyethylene resin, high-density polyethylene resin, ethylene-α
-Selection of ethylene resins such as olefin copolymer resins, and polypropylene resins such as homopolypropylene resins, propylene-ethylene random copolymers, propylene-ethylene block copolymers, and polypropylene-α-olefin copolymers. Modified polyolefin resins obtained by acid-modifying these olefin-based resins by graft polymerization or the like can also be used. The polyolefin resin described above may be used alone or in a blend of two or more.

Example 1 A low-density polyethylene resin having a thickness of 20 μm (density = 0.
395 g / m ² of paperboard laminated with 923 g / cm ³ ) and a thickness of 40 × 10 ⁻³ μm as the gas barrier layer 3.
A 30 μm thick low density polyethylene resin (density = 0.923 g) was used between the paperboard and the deposition surface of the deposited PET film using an extruder using a 12 μm thick PET film on which silicon oxide was deposited. / Cm ³ ) at a resin temperature of 310 ° C. and sand lamination to obtain a laminated film. The non-deposited surface of the vapor-deposited PET film of the laminated film is subjected to corona treatment, and a linear polyethylene resin (trade name: NH745N, Nippon Polyolefin Co., Ltd.) is used as the adhesive resin 5 by using an extruder on the corona-treated surface. Was extruded at a resin temperature of 310 ° C. with a thickness of 50 μm to obtain a packaging material of the present invention.

Example 2 As a substrate 1, a low-density polyethylene resin having a thickness of 20 μm (density = 0.
395 g / m ² of paperboard laminated with 923 g / cm ³ ) and a thickness of 40 × 10 ⁻³ μm as the gas barrier layer 3.
A 30 μm-thick low-density polyethylene resin (density = 0.923 g) was used between the paperboard and the vapor-deposited surface of the vapor-deposited PET film using an extruder using a 12 μm-thick PET film on which silicon oxide was deposited. / Cm ³ ) at a resin temperature of 310 ° C. and sand lamination to obtain a laminated film. The non-deposited surface of the vapor-deposited PET film of the laminated film is subjected to corona treatment, and the corona-treated surface is coated with an adhesive resin 5 using a co-extrusion extruder to form an ethylene-methacrylic acid-acrylate copolymer (trade name). : AN4228C, a resin manufactured by DuPont-Mitsui Co., Ltd .;
923 g / cm ³ low density polyethylene resin (trade name:
M-16P, Mitsui Chemicals, Inc.), and laminated in a melt extruder so that the thickness of the former resin is 10 μm and the thickness of the latter resin is 40 μm. Extruded at a temperature of 310 ° C. and laminated to obtain a packaging material of the present invention.

Example 3 An ONY film having a thickness of 25 μm was used as the substrate 1, and a gas barrier layer 3 having a thickness of 9 μm was used.
A two-layer film was prepared by using an aluminum foil having a thickness of μm and pasting it through a polyurethane adhesive. Next, a polyurethane-based adhesive was applied to one surface of a biaxially stretched polyester film having a thickness of 12 μm using a dry laminator machine,
The aluminum foil surface of the prepared two-layer film was adhered to obtain a three-layer film. A low-density polyethylene resin (trade name: JH707D, Nippon Polyolefin Co., Ltd.) obtained by subjecting the polyester film surface of the three-layer film to a corona treatment, and adding an epoxidized soybean oil as an adhesive resin 5 to the corona-treated surface by an extruder machine. )) And extruded at a resin temperature of 310 ° C. with a thickness of 50 μm and laminated to obtain a packaging material of the present invention.

Comparative Example 1 As a substrate 1, a low-density polyethylene resin having a thickness of 20 μm (density = 0.
395 g / m ² of paperboard laminated with 923 g / cm ³ ) and a thickness of 40 × 10 ⁻³ μm as the gas barrier layer 3.
A 30 μm thick low density polyethylene resin (density = 0.923 g) was used between the paperboard and the deposition surface of the deposited PET film using an extruder using a 12 μm thick PET film on which silicon oxide was deposited. / Cm ³ ) at a resin temperature of 310 ° C. and sand lamination to obtain a laminated film. The non-deposited surface of the vapor-deposited PET film of the laminated film is not corona-treated, and a conventional two-component curable polyurethane-based adhesive is applied to the surface with a dry laminator machine at 5 g / m ² to obtain a polyolefin-based film 7 having a low density. Polyethylene resin (trade name: M-14)
P, Mitsui Chemicals, Inc.)
And a packaging material for comparison was obtained.

<Evaluation> Using the packaging materials of Examples 1 to 3 and Comparative Example 1, the adhesive strength between the polyester film 4 and the sealant layer 10 was measured, and a bag using the packaging material was prepared. Is filled with distilled water and the sealant layer 1
The presence or absence of the eluted component that permeated through 0 was measured. Table 1 shows the measurement results. <Adhesive Strength Measuring Method> Each of the packaging materials was slit into a width of 15 mm, and the adhesive strength between the polyester film 4 and the sealant layer 10 was measured with a Tensilon type tensile tester. <Taste test method> A four-sided pouch having a size of 10 cm x 10 cm was prepared using the above-described prototype packaging material, filled with 150 ml of distilled water and sealed therein, and the four-sided pouch was allowed to stand at room temperature for one month. The distilled water was taken out and a taste test was performed.

[0027]

[Table 1]

As shown in Table 1, no unpleasant taste was felt from the distilled water filled in the pouches prepared in Examples 1 to 3, and the adhesive component was not found in the distilled water filled in the pouches prepared in Comparative Example 1. Off-taste due to elution into the pouch was felt. From these results, it was found that when the packaging material of the present invention was made into a pouch, the components derived from the adhesive did not elute inside the pouch. Furthermore, the adhesive strength between the polyester film 4 and the sealant layer 10 of the packaging materials of Examples 1 to 3 is larger than the adhesive strength of the packaging material of Comparative Example 1. The reason for this is that the surfaces of the polyester films of Examples 1 to 3 on the sealant layer 10 side are subjected to corona treatment.

[0029]

According to the packaging material of the present invention, when the sealant layer is laminated with the intermediate polyester film, the adhesive resin is extruded and laminated on the corona-treated surface of the polyester film at a resin temperature of 300 ° C. or more. Adhesive strength to polyester film is very strong, and conventional adhesives or anchors are not used, so various low molecular weight components caused by adhesives etc. penetrate the sealant layer,
It does not elute on the surface of the sealant layer and therefore does not adversely affect the taste of the contents. Furthermore, since the sealant layer is laminated on the polyester film in one step, a drying step such as a solvent by using a conventional adhesive,
Furthermore, since there is no need for an aging step such as accelerating the reaction of the adhesive, various advantages such as improvement in production efficiency can be expected.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a packaging material according to an embodiment of the present invention.

FIG. 2 is a side sectional view of a packaging material according to another embodiment of the present invention.

FIG. 3 is a side sectional view of a packaging material according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Adhesive layer 3 ... Gas barrier layer 4 ... Polyester film 5 ... Adhesive resin 6 ... Low density polyethylene resin 7 ... Polyolefin film 10 ... Sealant layer 20 ... Corona treated surface

Continued on the front page F-term (reference) 3E086 AB01 BA04 BA15 BA24 BB01 BB52 CA01 CA11 DA01 4F100 AA20 AK01A AK01D AK04D AK04J AK06 AK06D AK06E AK25D AK25J JA41 AK41 AK41C AK62D AK63 JL11D JL12D 4J002 BB03W BB05W CD16X GF00 GJ01

Claims (6)

[Claims] 1. A packaging material comprising a laminate comprising a substrate, a gas barrier layer, a polyester film, and a sealant layer, wherein the sealant layer comprises an adhesive resin extruded at a resin temperature of 300 ° C. or higher. 2. A laminate comprising a base material, a gas barrier layer, a polyester film, and a sealant layer, wherein the sealant layer comprises an adhesive resin coextruded at a resin temperature of 300 ° C. or higher and a low density polyethylene resin. Packaging material. 3. A laminate comprising a base material, a gas barrier layer, a polyester film, and a sealant layer, wherein the sealant layer is formed by laminating a polyolefin film on an adhesive resin extruded at a resin temperature of 300 ° C. or higher. Characteristic packaging material. 4. The packaging material according to claim 1, wherein the surface of the polyester film on the sealant layer side is surface-treated by a corona treatment method. 5. The method according to claim 1, wherein the adhesive resin has a density of 0.850 to 0.5.
The packaging material according to any one of claims 1 to 4, characterized in that it consists of 910 g / cm ³ of linear low density polyethylene resin. 6. The adhesive resin according to claim 1, wherein the adhesive resin is an ethylene / (meth) acrylic acid copolymer.
(Meth) acrylate copolymer, ethylene / (meth) acrylate copolymer, polyethylene or linear low-density polyethylene or low-crystalline ethylene / α
The packaging material according to any one of claims 1 to 4, comprising a resin obtained by adding epoxidized soybean oil to an olefin copolymer.