JP2016203634A - Retort stand-up pouch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a retort stand-up pouch in which the speed of recovery of gas barrier performance after a retort treatment is high, and high gas barrier performance can be maintained stably.SOLUTION: This retort stand-up pouch includes: a substrate film; and a laminated material having, on one surface of the substrate film, a polyamide resin layer, an ethylene-vinyl ester copolymer saponification product layer, and a heat sealing resin layer, the polyamide resin layer and the ethylene-vinyl ester copolymer saponification product layer being adjacent to each other.SELECTED DRAWING: None

Description

  The present invention relates to a stand-up pouch for retort, and more particularly to a stand-up pouch for retort that has a high recovery rate of gas barrier properties after retorting and that can stably maintain high gas barrier properties.

  Packaging materials such as foods and beverages are required to have functions such as retort resistance and heat resistance in order to prevent the elution of the packaging materials during heat sterilization and the accompanying deterioration in the flavor of the contents.

  As packaging containers for foods and the like, self-standing bags (also called stand-up pouches) that are lighter than conventional bottles and cans and excellent in volume reduction after use have become widespread. As a film material constituting the stand-up pouch, there are many configurations having a gas barrier property from the viewpoint of rigidity capable of self-supporting when the contents are filled and prevention of deterioration of the contents. As a film material having these properties, a laminated film composed of an aluminum foil and a polymer film has been used.

  However, the stand-up pouch mainly composed of aluminum foil has a problem that a consumer cannot use a microwave oven, particularly with respect to food packaging materials, and there is an increasing demand for a stand-up pouch that does not use aluminum foil.

  On the other hand, it has been proposed to use a vapor-deposited film formed from an inorganic oxide such as silicon oxide or aluminum oxide as a film substrate that can obtain a relatively high gas barrier property without using an aluminum foil. In the case of a vapor-deposited film of an object, although it has excellent gas barrier properties, it lacks bending resistance and the like, so that there is a problem that pinholes are easily generated and the gas barrier properties are remarkably impaired.

  As a means for solving such problems, it is obtained by polycondensation by a sol-gel method containing at least one alkoxide and a vinyl alcohol resin on the surface of a vapor-deposited film of an inorganic oxide such as silicon oxide or aluminum oxide. Providing a gas barrier coating film has been proposed (see, for example, Patent Document 1).

The disclosed technology of Patent Document 1 described above has a gas barrier coating film obtained by polycondensation by a sol-gel method and an inorganic oxide vapor-deposited film synergistically and has flex resistance, so that high gas barrier properties are stably maintained. In addition, it has excellent retort resistance and the like.
However, since it is necessary to separately provide a gas barrier coating film on the surface of the inorganic oxide vapor-deposited film, the production efficiency is poor, and it is also necessary to strictly control production, which makes the film expensive. There was a problem such as.

  In recent years, further enhancement of functions for packaging containers has been demanded, and oxygen barrier properties that prevent the entry of oxygen from the outside in order to suppress oxidation, carbon dioxide barrier properties, and barrier properties for various aroma components are also required. Has been. When imparting a barrier function to a multilayer film, unstretched polyolefin films used for the inner layer (sealant side) have poor gas barrier properties and are difficult to impart a barrier function by coating or vapor deposition. Therefore, a barrier function is often imparted to various films (polyester resins such as polyethylene terephthalate, polyamide resins, and stretched polyolefin resins) used on the outer layer side.

JP 2005-178804 A

  As these outer layer side films, polyvinyl alcohol resin having an oxygen barrier function or saponified ethylene-vinyl ester copolymer (hereinafter, saponified ethylene-vinyl ester copolymer may be referred to as “EVOH”). )), The barrier properties will be significantly reduced immediately after the retort treatment, and the quality of contents such as food in the packaging container will deteriorate unless the barrier properties are improved quickly after the hot water treatment. There was a problem.

  In view of the above, the present invention has an object to provide a stand-up pouch for retort that can quickly maintain a high gas barrier property with a high recovery speed of the gas barrier property after retort treatment under such a background. To do.

  However, as a result of intensive studies in view of such circumstances, the present inventor has made a stand-up for retort made of a laminated material having a polyamide resin layer, an EVOH layer, and a heat seal resin layer on one surface of the base film. In the pouch, the polyamide resin layer and the EVOH layer are adjacent to each other, so that the recovery rate of the gas barrier property after the retort treatment is high and the high gas barrier property can be stably maintained. As a result, the present invention was completed.

That is, the gist of the present invention is the following (1) to (7).
(1) A base film and a polyamide resin layer, an ethylene-vinyl ester copolymer saponification layer and a heat seal resin layer on one surface of the base film, the polyamide resin layer and the A stand-up pouch for retort comprising a laminated material in which a saponified ethylene-vinyl ester copolymer layer is adjacent.
(2) The stand-up pouch for retort according to (1), wherein the polyamide-based resin layer is provided between the base film and the ethylene-vinyl ester copolymer saponified product layer.
(3) The stand-up pouch for retort according to (1) or (2), wherein the polyamide resin layer has a thickness of 1 to 80 μm.
(4) The retort stand-up pouch according to any one of (1) to (3), wherein the saponified product layer of the ethylene-vinyl ester copolymer is 1 to 35 μm.
(5) The ratio (Tc / Tb) of the thickness (Tc) of the saponified product layer of the ethylene-vinyl ester copolymer and the polyamide resin layer (Tc / Tb) is 0.02 to 10. The stand-up pouch for retort according to any one of (1) to (4), which is characterized in that
(6) The stand-up pouch for retort according to any one of (1) to (5) above, wherein the heat seal resin constituting the heat seal resin layer is polypropylene.
(7) The stand-up pouch for retort according to any one of (1) to (6), wherein the base film is a polyester resin film.

  The retort stand-up pouch according to the present invention has a polyamide resin layer, an EVOH layer, and a heat seal resin layer on one surface of a base film, and the polyamide resin layer and the EVOH layer are adjacent to each other. The gas barrier property after retort treatment has a high recovery rate, and the high gas barrier property can be stably maintained.

FIG. 1 is a schematic cross-sectional view of a laminated material constituting a retort stand-up pouch according to the present invention. FIG. 2 is a schematic cross-sectional view of another laminated material constituting the retort stand-up pouch according to the present invention. FIG. 3 is an explanatory view showing an example of the stand-up pouch of the present invention.

  Hereinafter, although it demonstrates in detail about the structure of this invention, these show an example of a desirable embodiment and are not specified by these content.

In the present invention, the side for accommodating the contents of the retort stand-up pouch, that is, the sealant side is referred to as “inside”, and the opposite side is referred to as “outside”.
In the following description, terms such as “upper”, “lower”, “left”, and “right” are for convenience corresponding to the direction of the drawing.
In general, “film” refers to a thin flat product whose thickness is extremely small compared to the length and width and whose maximum thickness is arbitrarily limited, and is usually supplied in the form of a roll. "Sheet" refers to a product that is thin and generally flat with a small thickness instead of length and width (Japanese Industrial Standard JISK6900). However, since the boundary between the sheet and the film is not clear and it is not necessary to distinguish the two in terms of the present invention, the term “film” includes both “sheet” and the term “sheet”. Shall be included.

The present invention will be described in detail below with reference to the drawings.
First, the laminated material which comprises the stand-up pouch for retorts of this invention is demonstrated, illustrating the example of the layer structure. 1 and 2 are schematic cross-sectional views of a laminated material constituting a retort stand-up pouch according to the present invention.

  In addition, said illustration has illustrated the example about the laminated material which comprises the stand-up pouch for retorts concerning this invention, and this invention is not limited to this.

  For example, in the present invention, although not shown in the drawings, other resin layers, adhesive resin layers, and the like are arbitrarily laminated depending on the purpose of use, applications, etc., and laminated materials having various forms are designed and manufactured. It is something that can be done.

  The retort stand-up pouch of the present invention comprises a laminate having at least a base film 1, a polyamide resin layer 2, an ethylene-vinyl ester copolymer saponified product (EVOH) layer 3, and a heat seal resin layer 4. One surface of the base film 1 has a polyamide-based resin layer 2, an EVOH layer 3, and a heat seal resin layer 4.

  In the present invention, it is important to use the EVOH layer 3 as the gas barrier resin layer and to make the polyamide resin layer 2 and the EVOH layer 3 adjacent to each other. By making the polyamide resin layer 2 and the EVOH layer 3 adjacent to each other, the recovery rate of the gas barrier property after the retort treatment is increased. Moreover, it is preferable to arrange the polyamide resin layer 2 between the base film 1 and the EVOH layer 3 because the recovery rate of the gas barrier property after the retort treatment is increased. Further, as shown in FIG. 2, a polyamide resin layer 2 may be provided on both surfaces of the EVOH layer 3 so that the polyamide resin layer 2 sandwiches the EVOH layer 3.

  With the above configuration, the retort stand-up pouch of the present invention prevents the deterioration of the flavor due to the oxidation of the contents, and enables the contents to be stored for a long period.

  Next, in the present invention, a stand-up pouch for retort according to the present invention, which is formed by using the above laminated material, will be described. As a trunk | drum and bottom part of this stand-up pouch for retorts, the laminated material shown in FIG.1 and FIG.2 can be used, for example.

FIG. 3 is an explanatory view showing an example of the stand-up pouch of the present invention. The stand-up pouch 5 of the present invention is composed of two front and back body sheets 6 and 6 and a bottom sheet 7. The trunk sheet 6 and the bottom sheet 7 are sheets having flexibility, and are obtained by cutting the laminated material of the present invention into a desired size. The laminated material of the present invention is arranged so that the resin film layer is located on the inner side, that is, the base film 1 side is located on the outer side.
The bottom sheet 7 is inserted in a folded state between the lower parts of the two body sheets 6 and 6, and the bottom edge of the body sheets 6 and 6 and the peripheral edge of the bottom sheet 7 are sealed to form the bottom part. The seal part 8 is formed, and the side seal part 9 is formed by sealing the left and right edges of the stacked body part sheets 6 and 6. Thereby, in a state where the contents are filled, the bottom sheet 7 is expanded and becomes a stand-up pouch.

  In the present invention, with the upper portion of the stand-up pouch 5 opened, contents such as desired food and drink are filled from the opening. Next, the upper opening is heat-sealed to form a top seal portion and the like to produce a packaging semi-finished product. Thereafter, the packaging semi-finished product is subjected to a retort treatment such as a pressure heat sterilization treatment, etc. It is possible to produce a retort-packaged food having the following form.

  Below, each layer used for the laminated material which comprises the stand-up pouch for retorts of this invention is demonstrated.

<Base film>
As a base film used in the present invention, since this is a basic material constituting the stand-up pouch for retort according to the present invention, it has excellent strength in mechanical, physical, chemical, etc. It is preferable to use a resin film or sheet having excellent puncture resistance, heat resistance, moisture resistance, pinhole resistance, transparency and the like.

  Specifically, as the base film (A) constituting the base film, for example, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins such as various nylon resins, polyaramid resins, and polypropylene resins Films or sheets obtained from resins, polyethylene resins, polycarbonate resins, polyacetal resins, fluorine resins, and other tough resins can be used. Among them, polyester resin films obtained from polyester resins can be used. preferable.

  As the resin film or sheet, any of an unstretched film or a stretched film stretched in a uniaxial direction or a biaxial direction can be used.

In addition, the thickness of the base film in the present invention may be a thickness that can be retained for strength, puncture resistance, and the like, and if it is too thick, the cost tends to increase, and conversely if it is too thin. , Strength, puncture resistance and the like tend to decrease.
In the present invention, for the reasons described above, the thickness of the base film is preferably 10 to 100 μm, and particularly preferably 12 to 50 μm.

  Moreover, a printing layer can be suitably provided in a base film as needed. The printed layer is made of ink composed of solvent, binder resin such as urethane, acrylic, nitrocellulose, rubber, etc., various pigments, extender pigments, plasticizers, desiccants, stabilizers, etc. Layer. Characters, designs, etc. can be formed by this print layer. As the printing method, for example, known printing methods such as offset printing, gravure printing, flexographic printing, silk screen printing, and ink jet printing can be used. Moreover, the adhesiveness of a printing layer can be improved by giving the surface of a base film the corona treatment or the ozone treatment as a pretreatment beforehand. Usually, a printing layer is provided on the inner surface of the base film.

<Polyamide resin layer>
As the polyamide resin (B) constituting the polyamide resin layer used in the present invention, a known polyamide resin can be used. Specifically, examples of the polyamide resin (B) include polycapramide (nylon 6), poly-ω-aminoheptanoic acid (nylon 7), poly-ω-aminononanoic acid (nylon 9), polyundecanamide (nylon). 11) and homopolymers such as polylauryl lactam (nylon 12). Examples of the copolymerized polyamide resin include polyethylenediamine adipamide (nylon 26), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), and polyhexamethylene sebacamide. (Nylon 610), polyhexamethylene dodecamide (nylon 612), polyoctamethylene adipamide (nylon 86), polydecamethylene adipamide (nylon 108), caprolactam / lauryl lactam copolymer (nylon 6/12) Caprolactam / ω-aminononanoic acid copolymer (nylon 6/9), caprolactam / hexamethylene diammonium adipate copolymer (nylon 6/66), lauryl lactam / hexamethylene diammonium adipate copolymer (nylon 12/66) , Ethylenediamine adipamide / hexamethylene diammonium adipate copolymer (nylon 26/66), caprolactam / hexamethylene diammonium adipate / hexamethylene diammonium sebacate copolymer (nylon 66/610), ethylene ammonium adipate / hexa Aliphatic polyamides such as methylene diammonium adipate / hexamethylene diammonium sebacate copolymer (nylon 6/66/610), polyhexamethylene isophthalamide, polyhexamethylene terephthalamide, polymetaxylylene adipamide, hexamethylene Isophthalamide / terephthalamide copolymer, poly-p-phenylene terephthalamide, poly-p-phenylene-3-4′diphenyl ether terephthalamide, etc. Aromatic polyamide, amorphous polyamide, said polyamide resin methylene benzylamine, terminal modified polyamide obtained by modifying the ends with carboxyl group or an amino group such as meta-xylene diamine.

As thickness (Tb) of the polyamide-type resin layer in this invention, it is preferable that it is 1-80 micrometers, More preferably, it is 15-60 micrometers, Especially preferably, it is 20-40 micrometers.
The polyamide resin layer may be either a single layer or a plurality of layers. In the case of a plurality of layers, the total thickness of the polyamide resin layers may be in the above range.
If the polyamide resin layer is too thin, the gas barrier property recovery rate after retort treatment tends to be slow, and if it is too thick, the overall thickness of the stand-up pouch becomes thick, resulting in rigidity. There is a tendency that the opening property of the stand-up pouch when the food is actually filled is lowered.

<EVOH layer>
EVOH (C) constituting the EVOH layer used in the present invention is a resin usually obtained by saponifying a copolymer of ethylene and a vinyl ester monomer (ethylene-vinyl ester copolymer), It is a water-insoluble thermoplastic resin. The polymerization method can also be carried out using any known polymerization method such as solution polymerization, suspension polymerization, and emulsion polymerization. Generally, solution polymerization using a lower alcohol such as methanol as a solvent is used. Saponification of the obtained ethylene-vinyl ester copolymer can also be performed by a known method. EVOH produced in this manner mainly comprises ethylene-derived structural units and vinyl alcohol structural units, and contains a slight amount of vinyl ester structural units remaining without being saponified.

  As the vinyl ester monomer, vinyl acetate is typically used because it is easily available from the market and has good impurity treatment efficiency during production. Examples of other vinyl ester monomers include vinyl formate, vinyl propionate, vinyl valelate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl versatate, etc. Examples include aliphatic vinyl esters, aromatic vinyl esters such as vinyl benzoate, and the like. Usually, aliphatic vinyl esters having 3 to 20 carbon atoms, preferably 4 to 10 carbon atoms, and particularly preferably 4 to 7 carbon atoms are used. Can do. These are usually used alone, but a plurality of them may be used simultaneously as necessary.

  The ethylene content in EVOH (C) is a value measured based on ISO14663, and is preferably 20 to 60 mol%, more preferably 25 to 50 mol%, and particularly preferably 25 to 35 mol%. When the content is too low, the gas barrier property and melt moldability under high humidity tend to decrease, and when it is too high, the gas barrier property tends to decrease.

  The saponification degree of the vinyl ester component in EVOH (C) is a value measured based on JIS K6726 (where EVOH is a solution uniformly dissolved in water / methanol solvent), and is 90 to 100 mol%. Is more preferable, more preferably 95 to 100 mol%, particularly preferably 99 to 100 mol%. When the degree of saponification is too low, gas barrier properties, thermal stability, moisture resistance and the like tend to decrease.

  The melt flow rate (MFR) (210 ° C., load 2,160 g) of EVOH (C) is preferably 0.5 to 100 g / 10 minutes, more preferably 1 to 50 g / 10 minutes, and particularly preferably. Is 3 to 35 g / 10 min. If the MFR is too large, the film forming property tends to be lowered, and if it is too small, the melt viscosity becomes too high and melt extrusion tends to be difficult.

  EVOH (C) used in the present invention further includes structural units derived from the following comonomer in addition to ethylene structural units and vinyl alcohol structural units (including unsaponified vinyl ester structural units). May be. Examples of the comonomer include α-olefins such as propylene, isobutene, α-octene, α-dodecene, α-octadecene; 3-buten-1-ol, 4-penten-1-ol, 3-butene-1, Hydroxyl group-containing α-olefins such as 2-diols and hydroxy group-containing α-olefin derivatives such as esterified products and acylated products thereof; unsaturated carboxylic acids or salts thereof, partial alkyl esters, fully alkyl esters, nitriles, amides or anhydrous Unsaturated sulfonic acid or its salt; Vinyl silane compound; Vinyl chloride; Styrene.

  Furthermore, “post-modified” EVOH-based resins such as urethanization, acetalization, cyanoethylation, oxyalkyleneation, and the like can also be used.

  Among the modified products as described above, EVOH in which a primary hydroxyl group is introduced into a side chain by copolymerization is preferable from the viewpoint of good secondary formability such as stretching treatment and vacuum / pressure forming, among which 1,2- EVOH having a diol structure in the side chain is preferred.

  In the EVOH (C) used in the present invention, a compounding agent generally blended with EVOH, for example, a heat stabilizer, an antioxidant, an antistatic agent, a colorant, an ultraviolet ray, within a range not inhibiting the effects of the present invention. Absorber, lubricant, plasticizer, light stabilizer, surfactant, antibacterial agent, desiccant, antiblocking agent, flame retardant, crosslinking agent, curing agent, foaming agent, crystal nucleating agent, antifogging agent, biodegradation additive An agent, a silane coupling agent, an oxygen absorbent and the like may be contained.

  Examples of the heat stabilizer include organic acids such as acetic acid, propionic acid, butyric acid, lauric acid, stearic acid, oleic acid, and behenic acid or the like for the purpose of improving various physical properties such as heat stability during melt molding. Alkali metal salts (sodium, potassium, etc.), alkaline earth metal salts (calcium, magnesium, etc.), zinc salts, etc .; or inorganic acids such as sulfuric acid, sulfurous acid, carbonic acid, phosphoric acid, boric acid, or the like Examples include alkali metal salts (such as sodium and potassium), alkaline earth metal salts (such as calcium and magnesium), and zinc salts.

  The EVOH (C) used in the present invention may be a mixture with other different EVOH. Examples of such other EVOH include those having different ethylene contents, those having different saponification degrees, and melt flows. Those having different rates (MFR) (210 ° C., load 2,160 g), those having different copolymerization components, those having different amounts of modification (for example, those having different contents of 1,2-diol structural units), etc. Can be mentioned.

Moreover, when manufacturing the packaging material of the package processed by hot water like retort food etc., it is preferable to use the EVOH resin composition containing the polyamide-type resin. Polyamide-based resin can form a network structure by interaction of amide bond with the hydroxyl group and / or ester group of EVOH (C), thereby preventing elution of EVOH (C) during retort treatment can do.
As this polyamide-type resin, a well-known thing can be used. For example, the same thing as the polyamide-type resin (B) mentioned above can be used.

  The thickness (Tc) of the EVOH layer is preferably 1 to 35 μm, more preferably 5 to 25 μm, and particularly preferably 10 to 20 μm. If the thickness is too thin, the gas barrier property tends to decrease, and if it is too thick, the recovery rate of the gas barrier property after retorting tends to decrease.

<Heat seal resin layer>
The heat seal resin layer used in the present invention may be any material that can be melted by heat and fused to each other. Examples of the heat seal resin (D) constituting the heat seal resin layer include polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, A polyolefin resin such as ethylene-methacrylic acid copolymer, ethylene-propylene copolymer, methylpentene polymer, polyethylene or polypropylene was modified with acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, or other unsaturated carboxylic acid. A resin film or sheet composed of one or more kinds of resins such as acid-modified polyolefin-based resin or a coating film thereof can be used.
Among these, linear low density polyethylene (LLDPE) or polypropylene having a waist on the film itself is preferable from the viewpoint of imparting sufficient self-supporting property to the stand-up pouch. Furthermore, polypropylene is particularly preferable from the viewpoint of suppressing elution after retorting at a relatively high temperature (120 ° C. or higher).

  The heat seal resin layer in the present invention can be used as a single layer or multiple layers, and the thickness of the heat seal resin layer is preferably 30 to 300 μm, more preferably 35 to 200 μm, still more preferably 40 to 100 μm. It is. If the thickness is too thin, the sealing strength of the seal portion tends to decrease, and if it is too thick, the rigidity increases, and the opening property when filling the stand-up pouch with food or the like tends to decrease.

  The laminated material constituting the stand-up pouch for retort of the present invention is a layer other than the above base film, polyamide resin layer, EVOH layer, heat seal resin layer, for example, other resin layer, adhesive resin layer, etc. It may have an arbitrary layer.

<Other resin layers>
As the resin constituting the other resin layer, a known resin can be used. Specific examples of such resins include, for example, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyamide resins such as various nylon resins, polyaramid resins, polypropylene resins, polyethylene resins, and polycarbonate resins. Resins, polyacetal resins, fluorine resins, and the like can be used.

  The thickness of the other resin layer is preferably 1 to 100 μm, more preferably 5 to 90 μm, and particularly preferably 10 to 80 μm.

<Adhesive resin layer>
As the adhesive resin constituting the adhesive resin layer, known ones can be used. Examples of adhesive resins typically include modified polyolefin polymers containing carboxyl groups obtained by chemically bonding unsaturated carboxylic acids or their anhydrides to polyolefin resins by addition reaction or graft reaction. Can do. For example, maleic anhydride graft-modified polyethylene, maleic anhydride graft-modified polypropylene, maleic anhydride graft-modified ethylene-propylene (block and random) copolymer, maleic anhydride graft-modified ethylene-ethyl acrylate copolymer, maleic anhydride graft Modified ethylene-vinyl acetate copolymer, maleic anhydride-modified polycyclic olefin resin, maleic anhydride graft-modified polyolefin resin, and the like, and one or a mixture of two or more selected from these can be used.

  The thickness of the adhesive resin layer is preferably 1 to 30 μm, more preferably 2 to 20 μm, and particularly preferably 3 to 10 μm.

  Next, the manufacturing method of the laminated material which has the said base film, a polyamide-type resin layer, EVOH layer, and a heat seal resin layer is demonstrated.

<Manufacturing method of laminated material>
The laminated material in the present invention includes, for example, (1) a method of laminating a multilayer film having a polyamide resin layer, an EVOH layer and a heat seal resin layer on a substrate film, and (2) a polyamide resin layer on the substrate film. , EVOH layer, heat-seal layer laminating method, (3) Laminate any of the base film, polyamide resin layer, EVOH layer, and heat-seal resin layer, and laminate the remaining layers Obtained by a method or the like. Among these, from the viewpoint that the cost required for stacking can be reduced, the method (1) above in which the number of stacking is only one is preferable.

First, the manufacturing method of the multilayer film which has a polyamide-type resin layer, EVOH layer, and a heat seal resin layer, especially the multilayer film by which a polyamide-type resin layer / EVOH layer / heat seal resin layer is laminated | stacked in this order is demonstrated.
The multilayer film including the EVOH layer used in the present invention can be laminated by a melt molding method, a wet lamination method, a dry lamination method, a solventless lamination method, an extrusion lamination method, a coextrusion lamination method, an inflation method, or the like. Among them, the melt molding method is preferable from the viewpoint of the environment in which no solvent is used and the cost of not having to perform lamination in a separate process. As such a melt molding method, a known method can be employed. Examples include extrusion molding methods (T-die extrusion, tubular film extrusion, blow molding, melt spinning, profile extrusion, etc.), injection molding methods, and the like. The melt molding temperature is usually selected appropriately from the range of 150 to 300 ° C.

Then, the method to laminate | stack the said base film and the said multilayer film is demonstrated.
As a method of laminating the base film and the multilayer film, a laminating method used when producing a normal packaging material, for example, a wet lamination method, a dry lamination method, a solventless lamination method, an extrusion lamination method, a co-extrusion method. It can be performed by a lamination method, an inflation method or the like.
Thus, in the present invention, when performing the above lamination, if necessary, for example, pretreatment such as corona treatment, ozone treatment, and flame treatment may be optionally applied to the surface of the substrate to be laminated. it can.
In the above, when extrusion lamination is performed, for example, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer. Acid-modified polyolefin resins obtained by modifying polyolefin resins such as polymers, ethylene-propylene copolymers, methylpentene polymers, polyethylene or polypropylene with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, etc. Etc. can be used as a resin for melt extrusion lamination.

  At that time, for example, isocyanate-based, polyethyleneimine-based, other anchor coating agents, and the like can be arbitrarily used as an adhesion assistant.

  In the present invention, when dry laminating, for example, a solvent type, aqueous type, emulsion type laminate, etc. whose main component is a vinyl type, acrylic type, polyurethane type, polyamide type, polyester type, epoxy type or the like. An adhesive or the like can be used.

  In addition, the structure of multiple types of base film and a multilayer film (for example, base film / base film / multilayer film) is also possible. Moreover, the structure of a base film / multilayer film / base film is also possible. Regarding the lamination of the base films, they can be laminated by the same method as described above.

<Layer thickness>
In the present invention, the total thickness of the laminated material for a stand-up pouch including the base film is preferably 50 to 200 μm, particularly preferably 60 to 190 μm, and further preferably 70 to 180 μm. If the total thickness is too thin, there is a tendency that rigidity for maintaining the self-supporting property cannot be obtained. On the other hand, if it is too thick, the rigidity is too large, and the openability when the stand-up pouch is actually filled with food or the like tends to be lowered. The openability in the present invention refers to a characteristic that can easily be applied to automatic packaging by filling an object to be packaged with a gas such as air that is blown into the packaging bag mouth.

  In the present invention, the thickness of the multilayer film comprising the polyamide resin layer, the EVOH layer and the heat seal resin layer constituting the laminated material for the stand-up pouch cannot be said unconditionally depending on applications, packaging forms, required physical properties, etc. Is preferably 1 to 150 μm, more preferably 5 to 145 μm, and particularly preferably 10 to 140 μm.

The ratio (Tc / Tb) between the EVOH layer thickness (Tc) and the polyamide resin (B) layer thickness (Tb) is preferably 0.02 to 10, more preferably 0.05 to 5. Particularly preferred is 0.1 to 0.9, especially 0.15 to 0.6.
If the thickness ratio is too small, the gas barrier property tends to decrease, and if it is too large, the gas barrier property recovery after retorting tends to be delayed.
In addition, when each layer is a plurality of layers, the sum of the layer thicknesses may be in the above range.

  Next, a specific method for manufacturing the stand-up pouch of the present invention will be described.

<Manufacturing method of stand-up pouch>
For example, gravure printing is performed on one side of the base film using a gravure ink using a urethane resin as a binder. The multilayer film provided with the EVOH layer is bonded to the printing surface of the base film by, for example, a dry lamination method through a two-component curable urethane adhesive. In this case, the adhesive is applied to the entire printing surface and bonded to form a laminated material. The formed laminated material becomes base film / printing layer / multilayer film.

  Next, in order to form a stand-up pouch, the laminated material is slit to a predetermined width to form a trunk sheet and a bottom sheet. As shown in FIG. 3, the two body sheets 6, 6 are overlapped so that the multilayer film side faces each other, and the bottom sheet 7 is sandwiched between the lower parts of the two body sheets 6, 6, The left and right sides are sealed to form a bottom seal portion 8 and left and right side seal portions 9, respectively, and a top portion, that is, a stand-up pouch 5 having an open top is formed. At this time, a plurality of gap portions including unsealed portions surrounded by the seal portions in the longitudinal direction are formed in at least one side seal portion 9.

  Next, air is press-fitted into the gap. A method for forming the air enclosure will be briefly described. A press-fitting hole for press-fitting air is formed at the end in the longitudinal direction of the formed gap. The press-fitting hole may be a hole that penetrates the trunk sheet 6. In order to press-in air from the press-fitting hole, another press-fitting nozzle is brought into contact with the press-fitting hole. Forming part. Thereafter, the press-fitting hole is sealed. That is, the press-fitting hole is closed by the heat seal layer to form an air enclosing part.

  Next, the stand-up pouch 5 of the present invention is formed by expanding the bottom sheet of the packaging bag with the top open and filling the contents, and then sealing the top to form and seal the top seal. Is formed. Further, although the air sealing portion is formed in one side seal portion 9, it may be formed in both side seal portions 9. Independence can be further improved.

  The stand-up pouch formed in this way improves independence, and even if the contents are used and the contents are reduced, the side seal does not deform due to breakage of the side seal or crunch of the packaging bag, etc. On the other hand, since it can be bent between the air enclosure and the air enclosure, the packaging bag can be reduced in volume and stored. Even when discarded after use, the volume of the packaging bag can be reduced by folding and folding the space between the air enclosure and the air enclosure.

The retort processing conditions in the retort stand-up pouch of the present invention will be described.
As the retort processing method in the present invention, for example, a normal retort kettle is used, and the processing temperature varies depending on the contents and the packaging container, but cannot be generally described, but is generally 110 to 180 ° C., preferably 120 to 150. ° C. In addition, the treatment time varies depending on the contents, packaging container, retort treatment temperature, etc., and cannot be generally specified, but is generally 20 to 60 minutes, preferably 30 to 60 minutes. Can do.
Thus, in the present invention, the contents can be subjected to heat sterilization, heat sterilization cooking, or the like by the retort treatment as described above.

Next, a method for producing a retort packaged food using the retort stand-up pouch according to the present invention will be described.
Three sides of the laminated material produced above are sealed by heat sealing or the like, and then the contents are filled from the opening, and then the opening is sealed to the upper end by heat sealing or the like according to the present invention. Produces semi-finished packaging products that use retort stand-up pouches. Then, the retort packaged food using the stand-up pouch for retort according to the present invention can be produced by subjecting the semi-finished package to a heat treatment such as a retort treatment.

  Examples of the contents to be filled and packaged in the packaging bag constituting the retort stand-up pouch according to the present invention include cooked foods, marine products, frozen foods, boiled foods, rice cakes, liquid soups, seasonings, drinking water, and others. Such as curry, stew, soup, meat sauce, hamburger, meatball, sweet potato, oden, porridge, etc., fluid food, jelly-like food, seasoning, water, etc. Various foods and the like can be listed.

  Thus, the stand-up pouch of the present invention can stably maintain the gas barrier property after retort processing and the high gas barrier property, and is excellent in filling and packaging contents, quality maintenance, etc. It is useful as a stand-up pouch for retort.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the description of the examples unless it exceeds the gist.
In the examples, “part” means a weight basis.

<Example 1>
-As a base film (A), the extending | stretched polyethylene terephthalate film, the product made by phthalamura chemical Co., Ltd., grade: FE2001A, thickness: 12 micrometers was used.
-As the polyamide-based resin (B), nylon 6, "UBE nylon" manufactured by Ube Industries, grade: 1020 was used.
-EVOH (C) used was EVOH having an ethylene content of 29.4 mol%, a saponification degree of 99.7 mol%, and an MFR of 5.2 g / 10 min (230 ° C, load 2160 g).
As the heat seal resin (D), polypropylene, “Novatec PP” manufactured by Nippon Polypro Co., Ltd., grade: BC6DRF was used.
-As the adhesive resin, polypropylene adhesive resin, "Modic" manufactured by Mitsubishi Chemical Corporation, grade: 614V was used.

[Manufacture of laminated materials]
First, a multilayer film was manufactured, and the multilayer film and the base film were stacked to manufacture a laminated material.

<Manufacture of multilayer film>
Film formation by the T-die method was performed to obtain a multilayer film of polyamide resin layer (10 μm) / EVOH layer (20 μm) / adhesive resin layer (5 μm) / heat seal resin layer (65 μm).
(Film forming conditions)
・ Polyamide resin layer: 40mmφ single screw extruder (barrel temperature: 220 ° C)
EVOH layer: 40mmφ single screw extruder (barrel temperature: 230 ° C)
-Adhesive resin layer: 32mmφ single screw extruder (barrel temperature: 200 ° C)
Heat seal resin layer: 40mmφ single screw extruder (barrel temperature: 210 ° C)
-Die: Feed block die (die temperature: 230 ° C)
・ Cooling roll temperature: 50 ° C

<Lamination of multilayer film and substrate film>
The base film and the multilayer film obtained above were used as an adhesive for dry lamination (main agent: “TM-242A” manufactured by Toyo Morton Co., Ltd., curing agent: “CAT-RT37L” manufactured by Toyo Morton Co., Ltd. : Ethyl acetate = 17: 1.5: 19.2) was used for dry lamination to produce a laminate.
(Lamination condition)
-It bonded together in 20 degreeC environment and aged at 40 degreeC for 48 hours, The following evaluation was performed about the obtained laminated material.

[Gas barrier properties after bending test]
The laminated material obtained above was cut into a 10 cm × 10 cm square shape, folded in half, and returned to the oxygen gas permeation measuring device (OX-TRAN 2/21, manufactured by Mocon). (23 ° C., internal 100% RH, external 50% RH) was measured. The results are shown in Table 1.

<Comparative Example 1>
Instead of the laminated material used in Example 1, PET film (12 μm) laminated with vapor deposition of alumina (GL / ARH), nylon (15 μm) (manufactured by Unitika Ltd., Emblem ONMB- RT), biaxially oriented polypropylene (60 μm) (Toray Film Processing Co., Ltd., Treffan NOZK-207), using the same adhesive for dry lamination as in Example 1, and between the PET / nylon and the nylon / Laminated between the polypropylene to obtain a laminate. The obtained laminated material was evaluated in the same manner as in Example 1. The results are shown in Table 1.

  From the above results, on one side of the base film, when using a laminate material having a polyamide resin layer, an EVOH layer, a heat seal resin layer, and the polyamide resin layer and the EVOH layer being adjacent to each other, It can be seen that the oxygen permeation amount does not change before and after the bending test and stably exhibits high gas barrier properties.

<Example 2>
-As a base film (A), the extending | stretched polyethylene terephthalate film, the product made by phthalamura chemical Co., Ltd., grade: FE2001A, thickness: 12 micrometers was used.
-As the polyamide-based resin (B), nylon 6, "UBE nylon" manufactured by Ube Industries, grade: 1022B was used.
-EVOH (C) used was EVOH having an ethylene content of 29.4 mol%, a saponification degree of 99.7 mol%, and an MFR of 5.2 g / 10 min (230 ° C, load 2160 g).
As the heat seal resin (D), polypropylene, “Novatec PP” manufactured by Nippon Polypro Co., Ltd., grade: BC6DRF was used.
As the adhesive resin, a polypropylene-based adhesive resin, “Plexar” manufactured by LyondellBasel, grade: 6002 was used.

[Manufacture of laminated materials]
First, a multilayer film was produced, and a laminate was produced by laminating the multilayer film and a base film (see Table 2).

<Manufacture of multilayer film>
Film formation by the T-die method was performed to obtain a multilayer film of a polyamide resin layer (20 μm) / EVOH layer (20 μm) / adhesive resin layer (5 μm) / heat seal resin layer (55 μm).
(Film forming conditions)
・ Polyamide resin layer: 40mmφ single screw extruder (barrel temperature: 220 ° C)
EVOH layer: 40mmφ single screw extruder (barrel temperature: 230 ° C)
-Adhesive resin layer: 32mmφ single screw extruder (barrel temperature: 200 ° C)
Heat seal resin layer: 40mmφ single screw extruder (barrel temperature: 210 ° C)
-Die: Feed block die (die temperature: 230 ° C)
・ Cooling roll temperature: 50 ° C

<Lamination of multilayer film and substrate film>
A laminate was produced by dry laminating the base film and the multilayer film obtained above using the same dry laminating adhesive as in Example 1.
(Lamination condition)
-It bonded together in 20 degreeC environment and aged at 40 degreeC for 48 hours, The following evaluation was performed about the obtained laminated material.

[Gas barrier properties after hot water treatment]
The laminate material obtained above was cut into a 10 cm × 10 cm square shape, and after performing a retort treatment at 120 ° C. for 30 minutes using a retort device (manufactured by Nisaka Manufacturing Co., Ltd.), the sample was taken out and the oxygen gas permeation amount was measured. The oxygen permeability (23 ° C., internal 100% RH, external 50% RH) was measured using a device (manufactured by Mocon, OX-TRAN 2/21).

<Example 3>
In Example 2, a laminated material was produced in the same manner as in Example 2 except that the film thicknesses of the polyamide resin layer and the EVOH layer were changed to the film thicknesses shown in Table 2, and evaluated in the same manner.

<Example 4>
In Example 2, a laminated material was produced in the same manner as in Example 2 except that the film thickness and the layer configuration of the polyamide resin layer and the EVOH layer were changed to the film thicknesses shown in Table 3, and evaluated in the same manner.
The film forming conditions were as follows.
(Film forming conditions)
・ Polyamide resin layer: 40mmφ single screw extruder (barrel temperature: 220 ° C)
EVOH layer: 40mmφ single screw extruder (barrel temperature: 230 ° C)
-Adhesive resin layer: 32mmφ single screw extruder (barrel temperature: 200 ° C)
Heat seal resin layer: 40mmφ single screw extruder (barrel temperature: 210 ° C)
-Die: Feed block die (die temperature: 230 ° C)
・ Cooling roll temperature: 50 ° C

<Example 5>
In Example 4, a laminated material was produced in the same manner as in Example 4 except that the film thicknesses of the EVOH layer and the polyamide resin layer were changed to the film thicknesses shown in Table 3, and evaluated in the same manner.

<Comparative example 2>
In Example 2, the film thickness and the layer structure of the EVOH layer and the polyamide-based resin layer were changed to the film thicknesses shown in Table 4, and as other resin layers, polypropylene (“Novatech PP” manufactured by Nippon Polypro Co., Ltd., grade) : BC6DRF) was used, and a laminated material was produced in the same manner as in Example 2 and evaluated in the same manner.
The film forming conditions were as follows.
(Film forming conditions)
EVOH layer: 40mmφ single screw extruder (barrel temperature: 230 ° C)
-Adhesive resin layer: 32mmφ single screw extruder (barrel temperature: 200 ° C)
・ Other resin layers: 40mmφ single screw extruder (barrel temperature: 210 ° C)
Heat seal resin layer: 40mmφ single screw extruder (barrel temperature: 210 ° C)
-Die: 4 types, 5 layers type feed block die (die temperature: 230 ° C)
・ Cooling roll temperature: 50 ° C

  The evaluation results of Examples 2 to 5 and Comparative Example 2 are summarized in Table 5.

  From the above results, it can be seen that by making the polyamide resin layer adjacent to the EVOH layer, the recovery speed of the gas barrier property after the retort treatment is high.

  From the comparison between Example 2 and Example 4, even when the total thickness of the polyamide resin layer is the same, the recovery rate of the gas barrier property after the retort treatment is faster by laminating the polyamide resin layer on both sides of the EVOH layer. It was a result.

  From the comparison between Example 4 and Example 5, as a polyamide resin layer adjacent to the EVOH layer, by laminating a thick polyamide resin layer, the gas barrier property recovery rate after retort treatment is faster. It was.

  From the comparison between Example 3 and Example 2, in the laminated material in which the EVOH layer and the polyamide resin layer are adjacent, by reducing the ratio (Tc / Tb) of the EVOH layer and the polyamide resin layer, the retort-treated This resulted in a faster recovery rate of gas barrier properties.

  The stand-up pouch according to the present invention can stably maintain a gas barrier property and a high gas barrier property after retort treatment, and is excellent in filling and packaging of contents, quality maintenance, and the like. Therefore, it is useful as a stand-up pouch for retort filled with various foods and drinks such as cooked foods, marine products, frozen foods, boiled foods, rice cakes, liquid soups, seasonings, drinking water and others.

DESCRIPTION OF SYMBOLS 1 Base film 2 Polyamide-type resin layer 3 EVOH layer 4 Heat seal resin layer 5 Stand-up pouch 6 Trunk sheet 7 Bottom sheet 8 Bottom seal part 9 Side seal part

Claims (7)

  A base film, and a polyamide resin layer, an ethylene-vinyl ester copolymer saponified material layer, and a heat seal resin layer on one surface of the base film; the polyamide resin layer and the ethylene vinyl A stand-up pouch for retort comprising a laminated material in which an ester copolymer saponified product layer is adjacent.   The stand-up pouch for retort according to claim 1, wherein the polyamide-based resin layer is provided between the base film and the ethylene-vinyl ester copolymer saponified product layer.   The thickness of the said polyamide-type resin layer is 1-80 micrometers, The stand-up pouch for retorts of Claim 1 or 2 characterized by the above-mentioned.   The stand-up pouch for retort according to any one of claims 1 to 3, wherein a thickness of the saponified product layer of the ethylene-vinyl ester copolymer is 1 to 35 µm.   The ratio (Tc / Tb) between the thickness (Tc) of the saponified ethylene-vinyl ester copolymer layer and the thickness (Tb) of the polyamide resin layer is 0.02 to 10. The stand-up pouch for retorts according to any one of claims 1 to 4.   The stand-up pouch for retort according to any one of claims 1 to 5, wherein the heat seal resin constituting the heat seal resin layer is polypropylene.   The stand-up pouch for retort according to any one of claims 1 to 6, wherein the base film is a polyester resin film.

Images