JP2005096779A - Packaging bag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a packaging bag which is free from a crack formation due to bending that is a drawback of a packaging bag using a film lamination. <P>SOLUTION: The packaging bag (20) is mainly made of a composite member (10), which is composed of a plastic film base material (11), at least one surface of which has a vapor-deposited thin layer (12) made of an inorganic oxide, a paper member (13) laid on one surface of the base material (11), and a heat sealable plastic film (14) layered on the other surface of the base material (11). The paper member (13) is made of a hot water resistant paper having a weight per square meter of 60 to 180 g/m<SP>2</SP>and a density of 0.86 g/cm<SP>3</SP>, and is equivalent to 50% or more of the packaging bag (20) in weight percentage. The hot water resistant paper is preferably a paper impregnated with a polyisocyanate resin, and the packaging bag is preferably a standing pouch or a gusset pouch. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a packaging bag that requires excellent sealing properties and gas barrier properties for storing food, beverages, etc., and more specifically, during retort sterilization cooking after content filling or after content filling and distribution. The present invention relates to a packaging bag in which deterioration of gas barrier properties and water vapor barrier properties due to bending at the time is suppressed.

  Conventionally, as a container for food packaging, an inorganic oxide vapor deposition film such as silicon oxide has been used from the viewpoint of storage stability and heat resistance of contents. Moreover, when these films are bent unexpectedly at the time of filling the contents or at the time of distribution, cracks are generated in the deposited inorganic oxide layer, resulting in a decrease in gas barrier properties and water vapor barrier properties. In order to prevent the occurrence of cracks, various studies have been made such as resin coating or film lamination as a protective layer on one or both sides of an inorganic oxide vapor-deposited film. Also, when the internal pressure rises due to retort cooking sterilization after the contents are filled, cracks may occur in the inorganic oxide vapor deposition layer in the same manner in the vicinity of the bag-making seal portion.

  However, a packaging bag made of a film laminate cannot prevent bending due to filling or distribution, or pulling due to changes in internal pressure during sterilization cooking due to its flexibility, resulting in reduced gas barrier properties as a container. Has the disadvantage of inviting.

  On the other hand, due to serious environmental problems, easy disposal of containers and packaging materials is required, and composite containers manufactured by adhering an outer container made of paper and an inner container made of plastic are known. Furthermore, there is a composite container having hot water resistance in which the strength of the container is improved by using a paper member as resin-impregnated paper (see, for example, Patent Document 1).

The said prior art document is shown.
JP 2001-270563 A

  In order to solve the above-mentioned problems, the present invention is formed by molding a laminate in which a paper member is bonded to one surface of a plastic film having a vapor-deposited thin film layer made of an inorganic oxide on at least one surface. By proposing a packaging bag whose main component is a member formed by laminating a plastic film layer having heat sealability on the other surface of the plastic film, it is bent during filling, sterilization cooking, and distribution. It is to provide a packaging bag capable of cooking by retort sterilization by reducing the amount of plastic material used by preventing the deterioration of gas barrier properties and water vapor barrier properties, and by using a paper member having hot water resistance.

  The above problem can be solved by the following means.

In the first invention of the present invention, a paper member is bonded to one surface of a plastic film having a vapor-deposited thin film layer made of an inorganic oxide on at least one surface, and the other surface of the plastic film has heat sealability. A composite bag in which a plastic film layer is laminated is a main component, and the paper member has a basis weight of 60 g / m ² or more and 180 g / m ² or less and a density of 0.86 g / cm ^3. It is made of the above heat-resistant water paper, and the paper member is 5% of the weight of the packaging bag.
It can be obtained by making a packaging bag characterized by being 0% or more.

  The second invention of the present invention can be obtained by using the heat-resistant water paper made of polyisocyanate resin-impregnated paper as the packaging bag according to claim 1.

  The third invention of the present invention can be obtained by using the packaging bag according to claim 1 or 2, wherein the packaging bag has a standing pouch or a gusset pouch.

  Retort sterilization by reducing the amount of plastic material used by the present invention by preventing bending at the time of filling, sterilizing cooking, distribution, preventing deterioration of gas barrier property and water vapor barrier property, and making it a paper member having hot water resistance A cookable packaging bag can be provided.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to FIGS.

In the first invention of the present invention, a paper member (13) is bonded to one surface of a plastic film substrate (11) having a vapor-deposited thin film layer (12) made of an inorganic oxide on at least one surface, and the plastic film base A composite bag (10) formed by laminating a plastic film layer (14) having heat sealability on the other surface of the material is a packaging bag, the main component of which is a paper bag (13) having a basis weight Characterized in that it is made of heat-resistant water paper having a density of 60 g / m ² or more and 180 g / m ² or less and a density of 0.86 g / cm ³ or more, and the paper member is 50% or more of the weight of the packaging bag. It can be obtained by making it into a bag.

  As the plastic film substrate (11) used in the present invention, a plastic film is used in order to make use of the transparency of the deposited thin film layer. For example, polyethylene terephthalate (PET), polyester film such as polyethylene naphthalate, polyolefin film such as polyethylene and polypropylene, polystyrene film, polyamide film, polyvinyl chloride film, polycarbonate film, polyacrylonitrile film, polyimide film, etc. Either stretched or unstretched, and those having mechanical strength and dimensional stability are preferred. The transparent plastic material is processed into a film and used. In particular, polyethylene terephthalate arbitrarily stretched in the biaxial direction is preferably used. Moreover, in order to improve adhesiveness with a thin film, the surface of a base material can also be subjected to pretreatment such as corona treatment, low-temperature plasma treatment, and ion bombardment treatment. Alternatively, chemical treatment, solvent treatment, and the like may be performed.

  The thickness of the plastic film substrate (11) is not particularly limited, but it is suitable as a packaging material, when laminating other layers such as a transparent primer layer, an inorganic oxide vapor-deposited thin film layer, and a gas barrier coating layer. In consideration of workability and practicality, it is appropriately selected in the range of 6 to 30 μm.

  Next, the vapor-deposited thin film layer (12) made of an inorganic oxide in the present invention is characterized in that the inorganic oxide is aluminum oxide, silicon oxide, tin oxide, magnesium oxide or a mixture thereof. . Among them, aluminum oxide and silicon oxide are particularly preferable. Any material other than the above can be used as long as it has transparency and gas barrier properties such as oxygen and water vapor.

Moreover, the thickness of the vapor deposition thin film layer (12) which consists of inorganic oxides is the range of 5-300 nm in thickness. The optimum thickness of the thin film layer varies depending on the type and configuration of the inorganic compound used, but the value is appropriately selected. If the film thickness is less than 5 nm, a uniform film may not be obtained or the film thickness may not be sufficient, and the function as a gas barrier material may not be sufficiently achieved. On the other hand, when the film thickness exceeds 300 nm, flexibility cannot be maintained in the thin film, and the thin film may be cracked due to external factors such as bending and pulling after the film formation. A range of 10 to 150 nm is particularly preferable.

  Further, in order to provide a gas barrier property as high as that of the aluminum foil depending on the required quality, a primer or a gas barrier coating (not shown) for improving adhesion between the plastic film substrate (11) and the deposited thin film layer (12). ) May be provided, and a gas barrier coating layer (not shown) may be provided on the deposited thin film layer.

  In the present invention, the paper member (13) constituting the composite member (10) includes 100% virgin pulp cup paper including waste paper, NBKP material and LBKP material usage rate, wood It is possible to use paper made of various kinds of raw materials such as those made of kenaf and bamboo other than pulp, and those made of clay coating on one side. Moreover, it is not restrict | limited also to other materials, All the paper-like fiber structures which consist of pulp are included, and it is not limited to what is called a paper type. And what is necessary is just to select thickness suitably according to the objective. Moreover, the process for providing the desired function to these materials may be given. As long as it does not deviate from the fiber structure made of pulp such as paper, the material is not limited at all and may be appropriately selected according to the purpose.

Further, the basis weight of the paper member (13) depends on the properties of the paper member used, such as flexibility and rigidity required for the packaging bag, or light shielding properties, but may be selected as necessary. The basis weight is 60 g / m ² or more and 180 g / m ² or less, and the density is more preferably 0.86 g / cm ³ or more.

If the density of the paper member (13) is less than 0.86 g / cm ³ , the paper member itself will be crushed when the packaging bag (20) is bent, resulting in sharp bends and cracks in the inorganic oxide thin film layer. Occurs and the barrier property is lowered. If the density of the base paper is 0.86 / cm ³ or more, the stiffness of the paper itself is high, sharp bending can be prevented, and cracking of the inorganic oxide thin film layer can be prevented.

Further, the basis weight of the paper member (13) is preferably 60 g / m ² or more and 180 g / m ² or less. If the basis weight of the paper member is less than 60 g / m ² , the stiffness and rigidity of the entire packaging bag will be increased. It cannot be obtained sufficiently, and the stiffness and rigidity are dependent on the plastic film. On the other hand, when the basis weight of the paper member is larger than 180 g / m ² , the filling process and consumer handling may be impaired due to poor flexibility.

  Moreover, by using the heat resistant water paper as the paper member (13), the packaging bag of the present invention can perform boil sterilization cooking and retort sterilization cooking, and can store foodstuffs, seasonings, beverages and the like. Further, the paper member can also provide light shielding properties necessary for the retort food packaging material.

  Examples of the method for imparting hot water resistance to the paper member (13) include mixing and impregnation of resin materials in the paper making process. In addition, hot water resistance can be imparted to the paper in the paper impregnation process in the secondary process.

The resin component disposed in the draw molding precursor composed of a fiber structure mainly composed of pulp is capable of imparting the dry strength, water resistance, and wet strength of the draw molded body composed of the fiber structure. Synthesis of polyacrylamide and wet form paper strength enhancer such as urea formaldehyde resin, melamine formaldehyde resin, polyamidoamine, its epichlorohydrin modification, and various latexes such as natural rubber latex, SBR, NBR, polychloroprene, etc. Rubber latex, polyvinyl acetate, acrylic resin, polyvinyl chloride, polyvinylidene chloride and the like are used.

  In addition to thermosetting resins such as silane resins and melamine resins, resins that can be applied up to hot water resistance are also required to be thermoplastic resins such as acrylic resins, polyester resins, polyethylene resins and polypropylene resins. It can be selectively used depending on the water temperature.

Even when water repellency is required as an additional function, as long as the required hot water resistance is not impaired, it is also possible to use the above resin material in a composite or mixed form depending on the required function level. Any heat-resistant water paper can be selected and used as the outer container, and the heat-resistant water paper includes all fiber structures made of pulp and the like having heat-resistant water, and is limited to the types of so-called heat-resistant water paper. It is not something.

  A plastic film layer (14) having heat sealing properties such as polyethylene and polypropylene is provided as a sealant layer on the plastic film substrate (11) side of these laminates. The composite member (10) thus obtained is made into a packaging bag (20) through work processes such as cutting, bending, and bag making. As a shape of a packaging bag (20), things, such as a gable top type, a flat top type, a pouch, a gusset, can be mentioned, for example.

  The packaging bag of the present invention is made by reducing the thickness of the sheet for maintaining strength properties as much as possible from the conventional plastic sheet packaging bag, and supplementing the strength with paper. Furthermore, light shielding properties can be imparted by this paper member.

  As a method of laminating a plastic film base material on which a vapor-deposited thin film layer is formed, a paper member, and a plastic film layer having heat sealability, an anchor coat agent is used if necessary, and bonding is performed by a laminating method using an adhesive. To do. As these bonding methods, a general dry laminating method is preferable.

  Alternatively, if the contents to be stored do not require much light-shielding properties, it is possible to show the contents by not providing paper on a part or one side of the packaging bag, and the packaging bag is excellent in design. can do.

  Further, the paper member can also provide light shielding properties, and the light shielding properties can be improved with printing ink or the like depending on the required level. In addition, even if the contents to be stored need to be light-shielded, it is necessary to provide a part where the interior plastic pouch and the exterior paper are not bonded to each other, and further to provide perforations on the exterior paper of that part. Sometimes it is possible to remove the outer paper and show the contents.

  In the present invention, it is needless to say that not all elements constituting the packaging bag may be according to the structure of the present invention, and the present invention is partially applied to the target part or the part that does not impair the design. It can be applied without departing from the purpose. The same applies to the following inventions.

As the plastic film used by being bonded to the paper member, the same material structure as that used in the conventional plastic sheet pouch can be used. On the other hand, since the above-mentioned heat-resistant water paper gives rigidity, stiffness, and puncture resistance, select a material configuration that can provide gas barrier properties, impact resistance, heat sealing properties, etc. according to the required physical properties Since it is not necessary to ensure puncture resistance and pinhole resistance with a plastic film, the laminated structure of plastic materials and the thickness of each component can be reduced, and the amount of plastic material used can be greatly reduced. The use ratio of paper can be increased to 50% or more by securing the strength properties by the paper member, which is more preferable.

  The second invention of the present invention can be obtained by making the heat-resistant water paper a heat-resistant water paper made of polyisocyanate resin-impregnated paper.

  In addition, as a method for imparting hot water resistance to the paper pouch package, it is preferable to provide a hot water resistance by arranging a polyisocyanate resin on the paper member.

  In recent years, environmental problems have become serious, and containers and packaging materials are required to be easily disposed of. As containers and packaging materials, there is a demand to use paper members that are easily incinerated or recyclable. As a container using a paper member, a composite container manufactured by adhering an outer container of a paper member and an inner container of a plastic member is known. There is a composite container with improved container strength (see, for example, Patent Document 1). Furthermore, this patent document discloses that a polyisocyanate resin is impregnated as a means for imparting hot water resistance to a paper member serving as an exterior container of a composite container.

  This isocyanate resin has extremely high heat resistance, water resistance, and hot water resistance when placed on paper. By using an isocyanate resin-impregnated paper as the draw-molded body, a container having excellent shape retention and buckling strength can be obtained even in a dry state or a wet state.

  As isocyanate resins, various polyisocyanate compounds known so far, such as phenylene diisocyanate (PDI), tolylene diisocyanate (TDI), naphthalene diisocyanate (NDI), 4,4 ′ diisocyanate diphenylmethane (MDI), etc. Aromatic diisocyanates, xylylene diisocyanate (XDI) and other aliphatic aliphatic diisocyanates, hydrogenated TDI, hydrogenated XDI, hydrogenated MDI, hexamethylene diisocyanate (HMDI) isophorone diisocyanate (IPDI) and other aliphatic or alicyclic Triisocyanates such as diisocyanates and their derivatives, polyol adducts, burettes, trimers, trifunctional or higher polyisocyanates, lysine triisocyanate (LTI), etc. Other Aneto, can be used various oligomers containing isocyanate, a polymer.

  The amount of the resin distributed to the fiber structure to be the paper member (13) is 2% to 10% in the weight ratio of the impregnated paper even in the case of the agent capable of improving wet strength to a high degree such as the aforementioned isocyanate resin. preferable. Although depending on the structure of the impregnating agent used, impregnating paper can have a tensile strength when wet of 30% or more when dried by impregnating the above-mentioned isocyanate resin by 2% to 10% by weight. Further, even after hot water treatment corresponding to boil sterilization treatment or retort sterilization treatment, the tensile strength when wet can be 30% or more of that when dry. By setting in this way, heat resistance and water resistance can be improved, and shape retention and rigidity of the container when wet can be maintained.

  Further, as a method of arranging the resin component in the fiber structure, any method can be selected depending on required performance and cost such as internal addition or mixed papermaking in the papermaking stage, impregnation or spraying into the slurry.

  And it can also impregnate resin which can provide rigidity, water resistance, and hot water resistance as secondary processing after papermaking. As the impregnation method by the secondary processing, a dipping method in which a fiber structure is immersed in an impregnating agent and an excessive amount of the impregnating agent can be temporarily applied, or preferably a gravure coating in which a certain amount of the impregnating agent is applied or impregnated. Method, roll coating method, etc., and it is possible to impregnate from the front and back of the base fiber structure.

  The third invention of the present invention can be obtained by making the shape of the packaging bag a standing pouch or a gusset pouch.

  Many standing pouches and gusset pouches are distributed in a form that omits the paper box of the secondary container. Therefore, especially at the time of distribution, the container itself may be bent, and by using the packaging bag of the present invention, it is considered that bending can be prevented and the effect of preventing a decrease in barrier properties is great. Furthermore, the standing pouch shape can improve the independence, does not bow the top of the pouch, and is considered to have a great design effect at the store display.

  In the packaging bag of the present invention, cracking of the inorganic oxide thin film layer caused by bending during distribution or during sterilization cooking is more than that of a container formed by molding a laminate of a conventional inorganic oxide vapor-deposited film and base paper. It is possible to suppress the deterioration of gas barrier properties and water vapor barrier properties. Therefore, it is possible to prevent the intrusion of gas and moisture from the outside of the container or to keep the moisture in the container. It improves storage stability.

Hereinafter, specific examples of the present invention will be shown and described in detail.
<Example 1>
An alumina vapor-deposited thin film layer (12) is provided as an inorganic oxide vapor-deposited thin film layer (12) on a 12 μm-thick polyester film, which is a plastic film substrate (11). , 70 μm thick polypropylene as a sealant layer (14), and a sheet of paper (13) with a basis weight of 130 g / m ^{2 and} an isocyanate resin-impregnated paper excellent in heat-resistant water did. The bonding method is based on a dry laminating method using an adhesive. This was used as a flat member of a standing pouch to be a packaging bag (20).

  The bottom member is provided with an alumina vapor-deposited thin film layer as an inorganic oxide vapor-deposited thin film layer on a polyester film having a thickness of 12 μm, and a thickness of 15 μm-thick stretched nylon and sealant layer (14) is sequentially formed on the vapor-deposited thin film side. 70 μm polypropylene was bonded. The bonding method is based on a dry laminating method using an adhesive.

  With these members, a standing pouch which is a packaging bag (20) of Example 1 having a width of 140 mm, a height of 180 mm, and a bottom member width of 80 mm was molded (see FIG. 2).

The resulting standing pouch (20) was filled with food, subjected to a retort sterilization cooking at 121 ° C for 30 minutes, and the oxygen permeability before and after the food test was compared. The permeability was 0.02 ml / piece / day / 0.21 atm, and no decrease in oxygen permeability was observed. In addition, the standing pouch was excellent in independence during distribution, and the standing pouch was excellent in the store display effect without bowing. Further, this standing pouch has a paper member usage rate of 51% and can be discarded as paper waste after use.
<Example 2>
A standing pouch which is a packaging bag of Example 2 having a width of 140 mm, a height of 180 mm, and a bottom member width of 80 mm was molded using the bottom member of Example 1 as a flat member and a bottom member.

The obtained standing pouch was filled with food, subjected to retort sterilization cooking at 121 ° C for 30 minutes, and the oxygen permeability before and after food filling was compared. The permeability was 0.02 ml / piece / day / 0.21 atm, the oxygen permeability after the flow test was 0.07 ml / piece / day / 0.21 atm, and a decrease in oxygen permeability was observed. At the time of distribution, the standing pouch was not sufficiently independent, and the standing pouch would bow.

It is sectional explanatory drawing which shows one Example of the laminated constitution of the composite member used for the packaging bag of this invention. (A), (b) is a perspective explanatory drawing which shows one Example of the packaging bag of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Composite member 11 ... Plastic film base material 12 ... Deposition thin film layer 13 ... Paper member 14 ... Plastic film layer and sealant layer with heat sealability 20 ... Packaging bag

Claims (3)

A paper member is bonded to one surface of a plastic film substrate having a vapor-deposited thin film layer made of an inorganic oxide on at least one surface, and a plastic film layer having heat sealability is formed on the other surface of the plastic film substrate. A laminated bag comprising a laminated composite member as a main component, wherein the paper member has a basis weight of 60 g / m ² or more and 180 g / m ² or less and a density of 0.86 g / cm ³ or more. A packaging bag comprising paper and having a paper member of 50% or more of the weight of the packaging bag.   The packaging bag according to claim 1, wherein the heat-resistant water paper is made of polyisocyanate resin-impregnated paper.   The packaging bag according to claim 1 or 2, wherein the shape of the packaging bag is a standing pouch or a gusset pouch.