EP0537109A2 - Bag package - Google Patents

Abstract

A bag package for contents which can be heated by microwave treatment, comprises a shell part and, if appropriate, a bottom part made of flexible plastic film (1, 21), the front and rear side of the shell part and the possibly present bottom part being connected to one another by sealing seams (12, 13; 32, 33) so as to be resistant to separation, the shell part being formed by a plastic film which on the inside contains a tear-off layer, and the bag package having in the region of the upper closure of the shell part a removal aperture which is closed by a bag top seam (14, 34), and the bag having an automatic overpressure relief (6, 35) in the region of the upper closure. <IMAGE>

Description

The present invention relates to a bag packaging for filling materials which can be heated by microwave treatment, comprising a jacket part or a jacket and a bottom part, made of flexible plastic film, the front and back of the jacket part and the bottom part which may be present being connected to one another by sealing seams.

From DE-OS 1 786 019 bags and in particular stand-up bags made of thermoplastic or composite material are known, consisting of two side walls with a folded bottom or two separate side walls and a third pre-folded bottom film, the volume restricting adhesive welds or pressure sensitive adhesives being attached, which are attached release a strong increase in pressure so that voltage peaks are dampened by increasing the volume at these points.

The object of the present invention is to provide a gas- and liquid-tight bag packaging which can be sterilized, for example, and whose contents can later be reheated by microwave treatment, the volume expansion which occurs when the contents are heated, in particular by steam formation, and an excessive build-up of pressure by an automatic process Relief of excess pressure at a predetermined point to the ambient atmosphere, down to the ambient pressure, is prevented and finally an easy opening of the bag packaging for removal of the filling material is made possible.

The previously proposed solution for pressure relief could not solve the task at hand.

The object is achieved according to the invention in that the jacket part is formed from a plastic film which contains a tear layer (peel layer) on the inside and the bag packaging has a removal opening in the region of the upper end of the jacket part, which is closed by a bag head seam, and the bag has an automatic overpressure relief in the area of the upper end.

The tear-off layer described can also be referred to as a peel layer or peel layer.

In a first expedient embodiment of the bag packaging, the automatic overpressure relief represents a tear-open aid on the bag head seam.

The tear-open aid on the bag head seam can, for example, be at least one seam which is directed towards the inside of the bag and formed into a tip. Correspondingly, two or more tips of the same or different sizes can also be provided.

In a second expedient embodiment of the bag packaging, the automatic overpressure relief is arranged within the area of the bag interior in the form of an opening which can be torn open.

A recess of any shape, expediently round, can be provided as the tear-open opening. The opening can have a diameter of e.g. B. 1 to 10 mm, or an area of 1 to 100 mm², and is appropriately sealed by a seam in width and tear strength corresponding to the other seams. The seam connects the front and back of the jacket part on the one hand and encloses the opening in a gas and liquid-tight manner until the intended pressure relief.

The opening which can be tied open is preferably arranged within the region of the bag interior and in the immediate vicinity of the head bag seam.

The present invention relates to pouch packaging, the pouches being able to be constructed, for example, from a substantially centrally folded plastic film connected laterally via seams.

Other exemplary embodiments are the connection of two plastic films via two side seams and a bottom seam or the connection of two bag walls and a bottom, possibly for example V-shaped or W-shaped, made of plastic films by means of marginal ones Stitching.

Other embodiments are e.g. Bags, constructed from two bag walls and side inserts connected between the bag walls, connected at the edges, and optionally an inserted bottom. Both the inserts and the bottom can be made from a flat or e.g. V-shaped or W-shaped plastic film.

Bags made from a plastic film which is folded in the middle and provided with an inward-facing V-shaped fold are preferred. The V-shaped fold then represents the bottom. The inward-facing V-shaped fold usually protrudes 1/20 to 1/3, preferably 1/10 to 1/5, into the bag.

Instead of the V-shaped fold, e.g. a W-shaped fold can also be used analogously.

Marginal seams expediently connect the front and back of the jacket part and the legs of an inward V-shaped bottom fold, also marginally, separably to each other. This ensures that e.g. when filling such a bag or when building pressure in such a sealed bag, only the central part of the V-shaped fold can open. A stand-up pouch is formed.

A bag head seam is placed on the bag head for closing. The seams can all have the same width and / or tear resistance and each seam can have the same width and / or tear resistance over its entire length.

The present invention preferably relates to stand-up pouches or stand-up pouch packaging. Bag packs that are not stable can also be given standing properties by means of a suitable device, such as a holder, a foot part and the like.

Plastic films are used for the jacket part and the bottom part, plastic films being used for the jacket part and, if appropriate, the bottom part with a tear layer (peel layer) coming to the inside of the bag.

Suitable plastic films can have one or more layers and, in the latter case, can be laminates or film composites. The plastic films expediently contain a barrier layer against gases and vapors.

The plastic films can, for example, consist of olefin-based, ester-based, polyamide-based, vinyl halide-based plastics or mixtures thereof, or contain these plastics.

Examples of olefin-based thermoplastics are polyolefins, e.g. such as polyethylene, such as high-density polyethylene (HDPE, density greater than 0.944 g / cm³), medium-density polyethylene (MDPE, density 0.926-0.940 g / cm³), linear medium-density polyethylene (LMDPE, density 0.926-0.940 g / cm³), Low density polyethylene (LDPE, density 0.910-0.925 g / cm³) and linear low density polyethylene (LLDPE, density 0.916-0.925 g / cm³), polypropylene, amorphous or crystalline polypropylene, atactic or isotactic polypropylene or mixtures thereof, poly-1- butene, poly-3-methylbutene, poly-4-methylpentene and copolymers or coextrudates thereof, such as, for example of polyethylene with vinyl acetate, acrylic acid, e.g. B. ionomer resins, such as copolymers of ethylene with about 11% acrylic acid, methacrylic acid, acrylic esters, tetrafluoroethylene or polypropylene, as well as statistical copolymers, block copolymers or olefin polymer-elastomer mixtures.

Ester-based thermoplastics are, for example, polyalkylene terephthalates or polyalkylene isophthalates with alkylene groups or radicals having 2 to 10 carbon atoms or alkylene groups having 2 to 10 C atoms which are interrupted by at least one -O-, such as, for example, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate (polytetramethylene terephthalate) , Polydecamethylene terephthalate, poly-1,4-cyclohexyldimethylol terephthalate or polyethylene-2,6-naphthalene-dicarboxylate or polyalkylene terephthalate and polyalkylene isophthalate mixed polymers, the proportion of isophthalate being, for example, 1 to 10 mol%, mixed polymers and terpolymers, and block polymers and grafted polymers Modifications substances mentioned above.

Useful ester-based thermoplastics are polyalkylene terephthalates with alkylene groups or radicals with 2 to 10 carbon atoms and polyalkylene terephthalates with alkylene groups or radicals with 2 to 10 carbon atoms which are interrupted by one or two -O-.

Preferred thermoplastics based on esters are polyalkylene terephthalates with alkylene groups or radicals with 2 to 4 carbon atoms, and polyethylene terephthalates are very particularly preferred.

The amide-based thermoplastics include, for example, polyamide 6, a homopolymer of ε-caprolactam (polycaprolactan); Polyamide 11, a polycondensate of 11-aminoundecanoic acid (poly-11-aminoundecanamide); Polyamide 12, a homopolymer of ω-laurolactam (polylaurin lactam); Polyamide 6,6, a homopolycondensate of hexamethylene diamine and adipic acid (polyhexamethylene adipamide); Polyamide 6.10, a homopolycondensate of hexamethylene diamine and sebacic acid (polyhexamethylene sebacamide); Polyamide 6, 12 a homopolycondensate of hexamethylene diamine and dodecanedioic acid (polyhexamethylene dodecanamide) or polyamide 6-3-T, a homopolycondensate of trimethylhexamethylene diamine and terephthalic acid (polytrimethylhexamethylene terephthalamide), as well as mixtures thereof.

A non-exhaustive list of plastics based on vinyl halide includes, for example, the polymers of vinyl chloride and vinyl plastics containing vinyl chloride units in their structure, for example copolymers of vinyl chloride with vinyl esters of alphalic acids, in particular of vinyl acetate; Copolymers of vinyl chloride with esters of acrylic and methacrylic acid and with acrylonitrile; Copolymers of vinyl chloride with diene compounds and unsaturated dicarboxylic acids or their anhydrides, such as copolymers of vinyl chloride with diethyl maleate, diethyl fumarate or maleic anhydride; post-chlorinated polymers and copolymers of vinyl chloride; Copolymers of vinyl chloride and vinylidene chloride with unsaturated aldehydes, ketones and others such as acrolein, crotonaldehyde, vinyl methyl ketone, vinyl methyl ether, vinyl isobuyl ether, etc .; Polymers of vinylidene chloride and copolymers thereof with vinyl chloride and other polymerizable compounds; Polymers of vinyl chloroacetate and dichlorovinyl ether, chlorinated polymers of vinyl acetate., chlorinated polymeric esters of acrylic and alpha-substituted acrylic acids; Polymers of chlorinated styrenes, for example dichlorostyrene, chlorinated rubber, chlorinated polymers of chlorobutadiene and their copolymers with vinyl chloride; Rubber hydrochloride and chlorinated rubber hydrochloride; as well as mixtures of polymers with one another or with other polymerizable compounds and also the corresponding bromides and fluorides.

In the case of plastic films, laminates or film composites, a barrier layer against gases and vapors can preferably also be provided. Suitable are e.g. ceramic barrier layers, as well as plastic barrier layers.

Therefore, the present invention also relates to pouch packaging whose plastic film of the jacket part or the jacket part and the bottom part or the bottom part contains a barrier layer against gases and vapors.

Ceramic barrier layers contain, for example, oxides from the series of silicon oxides, aluminum oxides, iron oxides, nickel oxides, chromium oxides or lead oxides or mixtures thereof. The silicon oxides or aluminum oxides are expedient as ceramic barrier layers. The silicon oxides can have the formula SiO _x , where x preferably represents a number from 1 to 2, particularly preferably from 1.1 to 1.9 and in particular from 1.2 to 1.7. The aluminum oxides can have the formula Al _y O _z , where y / z is, for example, a number from 0.2 to 1.5 and preferably from 0.65 to 0.85.

The ceramic barrier layers are applied to a substrate, for example by a vacuum thin-film technique, expediently on the basis of electron beam evaporation or resistance heating or inductive heating from crucibles, e.g. applied to a plastic layer or plastic film, as mentioned above. Electron beam evaporation is preferred. The described methods can be carried out reactively and / or with ion support. The ceramic layer can have a thickness of, for example, 5 to 500 nm.

Plastic barrier layers can be made of polymers, for example are, are, or contain gas and water vapor tight. Layers or foils based on polyvinylidene chlorides, polyolefins, polyvinyl chlorides, acrylonitrile copolymers, polyethylene terephthalates or biaxially stretched polyethylene terephthalates, for example, behave particularly favorably.

Bag packaging according to the present invention, the barrier layer of which is a ceramic layer, is particularly preferred.

The thickness of the single-layer plastic films or of the individual plastic films in film composites or laminates can be, for example, 8 to 2000 μm, preferably 10 to 600 μm and in particular 10 to 80 μm.

Foil composites or laminates can have the layer structures known per se, such as e.g. containing at least two plastic layers or containing at least one cellulose-containing layer, such as paper, cardboard, nonwovens and at least one plastic layer.

In all embodiments, at least one printed, counterprinted or colored layer of a material, e.g. a plastic film may be provided.

At least one of the layers can be insulating and made of closed-cell plastic foam, e.g. made of polystyrene or other materials such as Crepe paper or similar consist.

The different layers, e.g. the plastic films or layers or composites with one another and the plastic films or layers containing ceramic barrier layers can be connected to one another with laminating adhesives and / or adhesion promoters.

Suitable adhesion promoters are, for example, vinyl chloride copolymers, vinyl chloride-vinyl acetate copolymers, polymerizable polyesters, vinyl pyridine polymers, vinyl pyridine polymers in combination with epoxy resins, butadiene-acrylonitrile-methacrylic acid copolymers, phenolic resins, rubber derivatives, acrylic resins, acrylic resins with phenol or

Epoxy resins, or organosilicon compounds, such as organosilanes.

EAA (ethylene acrylic acid) or modified polyolefins, such as e.g. modified polypropylene.

A preferred modified polypropylene is an adduct of maleic anhydride and an ethylene-propylene copolymer. Dispersions of modified polyolefins are very particularly preferred. An example of a modified polypropylene dispersion is Morprime (trademark of Morton Chemical Division of Norton Norwich Products, Inc.).

Further suitable adhesion promoters are adhesives such as nitrile rubber-phenolic resins, epoxides, acrylonitrile-butadiene rubber, urethane-modified acrylics, polyester-co-polyamides, hot melt polyester, cross-linked hot-melt polyester polyisocyanates polyisobutylenmodifizierte, styrene-butadiene rubbers, urethanes, ethylene-acrylic acid copolymers and ethylene vinyl acetate -Mixed polymers.

If, for example, laminating adhesives are used between the plastic layers, the laminating adhesives can be solvent-containing or solvent-free and also contain water. Examples are solvent-based or aqueous acrylate adhesives or solvent-free polyurethane adhesives.

Laminating adhesives based on polyurethane are preferred.

The jacket parts underneath and possibly with the bottom part are e.g. Separately connected by sealed seams. The plastic films have a tear-open layer on the surface of the plastic film coming to lie on the inside of the bag.

The tear-open layer can extend over the entire surface of the plastic film or can be present or applied only partially, in the area of the seals to be made.

The tear layer can be on the plastic film in film form or in Layer form, for example on both sides and expediently arranged on the surface of the plastic film to be located on the inside of the bag.

Tear-open layers are known per se and can, for example, be made of polyolefins or polyolefin mixtures, optionally with a filler, or contain such substances. Suitable polyolefins are, for example, LLDPE, LDPE, MDPE, HDPE, polypropylene, cast polypropylene (cPP), modified polypropylene or polypropylene copolymers, such as ethylene-propylene copolymers or polyethylene terephthalate, etc.

Other examples of tear-open layers are those containing or consisting of an ionomer resin, in particular with about 10% acid content and a high degree of ionic crosslinking; Ethylene acrylic acid copolymers; Ethylene / vinyl acetate copolymers; acid modified EVA copolymers or EVA.

Still other examples of tear layers are blends of polypropylene and high pressure polyethylene, blends of polypropylene and polyolefin rubbers.

Modified polyesters or glycol-modified polyesters or copolyesters of aromatic polycarboxyl compounds, ethylene glycol and an additional glycol are particularly preferred. The aromatic polycarboxyl compounds are e.g. aromatic dicarboxylic acids such as terephthalic acid. The additional glycols can have 3 to 20 carbon atoms and are e.g. Propanediols, butanediol, pentanediol, hexanediol or 1,4-cyclohexanedimethanol.

Preferred is, for example, a tear layer containing 40 to 97% by weight of at least one copolyester and 3 to 60% by weight of at least one thermoplastic polymer on acetal, acrylic, amide, carbonate, ester, olefin, styrene or vinyl base. The copolyester is expediently sealable.

Suitable copolyesters for such tear-open layers are copolyesters of an aromatic or aliphatic polycarboxyl compound, ethylene glycol and / or another glycol or polyglycol. The aromatic polycarboxyl compounds are expediently aromatic dicarboxylic acids. The aliphatic polycarboxyl compounds are expediently aliphatic dicarboxylic acids.

In addition to the polycarboxylic acid mainly present in the copolyester, expediently an aromatic bicarboxylic acid and preferably terephthalic acid, the copolyester can contain other polycarboxylic acids for modification. The proportion of the other polycarboxylic acid for modifying the copolyester can, for example, be up to 30 mol%. Several aliphatic, alicyclic or aromatic dicarboxylic acids with 4 to 36 carbon atoms, such as malonic acid, maleic acid, fumaric acid, succinic acid, glutaric acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, cis- or trans-1,4-cyclohexanedicarboxylic acid, 1,2- or 1,3-cyclohexanedicarboxylic acid, monochloterephthalic acid, such as 2-chloroterephthalic acid, dichloroterephthalic acid, such as 2,5-dichloterephthalic acid, methyl terephthalic acid, dimethyl terephthalic acid, tetrahydrophthalic acid, 4,4′-diphenyldicarboxylic acid, trans-4,4-stilbimedicino acid, Succic acid, sebacic acid, or dodecanedicarboxylic acid can be used. The copolyester can be produced either from the acid compound or from an ester or another reactive derivative.

The copolyester contains 5 to 97 mol% of ethylene glycol residues and 3 to 95 mol% residues of at least one additional glycol as the glycol or diol portion. Additional glycols are, for example, aliphatic and cycloaliphatic glycols with 3 to 20 C atoms, such as the aliphatic glycols 1,2- or 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,4-butanediol, 1 , 5-pentanediol, 1,6-hexanediol, 1,8-octanediol or the cycloaliphatic glycols 1,3- or 1,4-cyclohexanedimethanol, 2,2-dimethyl-1,3-propanediol, 2,2,4,4 -Tetramethyl-1,3-cyclobutanediol and also diethylene glycol or other suitable diols, as well as oligomers called diols.

The preferred copolyester for the present tear layers contains an aromatic polycarboxyl compound and in particular terephthalic acid or derivatives thereof and the additional glycol is in particular 1,4-cyclohexanedimethanol. Very preferred copolyesters are glycol-modified polyesters, which are known to experts in the field, for example, as PETG.

Particularly suitable copolyesters are, for example, the commercially available products "Kodabond 5116" from Eastman Kodak Co. or "SELAR PT 8307" from Du Pont.

Examples of thermoplastic polymers which are contained in the tear layer with the copolester (s) can be based on acetal, acrylic, amide, carbonate, ester, olefin, styrene or vinyl.

Preferred thermoplastic polymers which are contained in the tear layer with the copolester (s) are the polyolefins and in particular polyethylene or polypropylene, furthermore acid- or alcohol-modified copolymers, such as ethylene acrylic acid (EAA) or ethylene-vinyl alcohol copolymers, non-sealable polyesters, especially not sealable polyethylene terephthalates, polyamides, rubber elastomers, for example based on ethylene-propylene-diene elastomers and polycarbonates, in particular based on bisphenol A and phosgene. Polyethylenes are very particularly preferred as thermoplastic polymers which are contained in the tear layer with the copolester (s) and in particular LDPE applied.

A tear-open layer containing 75 to 90% by weight of at least one copolyester and 10 to 25% by weight of at least one thermoplastic polymer is preferred.

The tear layers can also contain, for example, 3 to 20% by weight of a filler.

Such fillers are known per se and organic fillers and / or mineral fillers with small particle size, such as chalk, talc, quartz, wollastonite, feldspar, calcined kaolinite clay and the like, can be mentioned by way of example. Other fillers are e.g. Titanium dioxide or other coloring pigments.

The tear-open layer, like the plastic films, can contain materials which are known per se and which improve properties, such as reinforcing agents, plasticizers, lubricants, antioxidants, light stabilizers, stabilizers and other polymer modifiers.

If necessary, the plastic film containing a tear layer on one side, a sealing layer on the other side, a colored, printed or counterprinted plastic film or a cellulose-containing layer such as paper, cardboard, non-woven fabric, or the plastic film can have a tear layer on both sides.

Preferred plastic films for the jacket part and the bottom part can, for example, be constructed from the outside in from a polyester layer, such as a polyester film, a barrier layer, such as a ceramic layer, a further polyester layer, such as a polyester film, and a tear-off layer, for example as described above.

Plastic foils for the jacket part and base part are particularly preferred, comprising a polyethylene terephthalate film, an SiO _x layer, from the outside in, where x is a number from 1.2 to 1.7, a further polyethylene terephthalate film and a tear-off layer, containing, for example polypropylene, cast polypropylene (cPP), polypropylene copolymer or sealable polyethylene terephthalate.

The thickness of the individual layers of this latter plastic film can be, for example, 10 μm to 50 μm for the polyethylene terephthal layers, 10 nm to 100 nm for the ceramic layer and 5 μm to 80 μm for the tear-off layer.

In practice, plastic films are, for example, containing a polyethylene terephthalate film with a thickness of 10-15 μm from the outside inwards, an SiO _x layer, where x is a number from 1.2 to 1.7 and the layer thickness is 10 nm to 100 nm, another polyethylene terephthalate film with a layer thickness of 10 to 15 μm and a tear-open layer in the form of a 40 to 60 μm thick PP or cPP film are preferred. The SiO _x layer is expediently applied to the further polyethylene terephthalate layer.

The bag packs according to the present invention are joined, for example, by sealing, welding, ultrasonic sealing or welding or gluing in the form of seams on the jacket parts and, if appropriate, the base part. Sealing and in particular thermal contact sealing is preferred. The strength of the sealing seams is influenced by the sealing geometry, the sealing temperature, the sealing pressure and the sealing time. If the seams are carried out using ultrasound, the necessary energy parameters must be observed accordingly.

The bag packages according to the present invention have e.g. separable sealed bottom and side seams.

The sealing seams are preferably set in such a way that a stand-up pouch results. For this purpose, the side seams and optionally the bottom seams are sealed, for example from a front and a rear side, which are obtained by folding a plastic film or by joining two plastic films. In the area of the bag foot part, sealing seams running diagonally from the outside downwards can be placed. This increases the inherent stability and stability of a bag. Furthermore, the side sealing seams at the transition from the 2-layer to the 4-layer bag part (in the area of the V-shaped folded bottom part) relieved. This latter embodiment is preferred for stand-up pouches.

For example, in the packaging of moisture-containing goods, e.g. from the food sector, the bag packaging can be filled, closed and, if necessary, sterilized under counter pressure. After being closed, the bag packaging is in particular gas and liquid-tight. Before the contents are consumed or consumed, the bag packaging can preferably be reheated by microwave treatment in the bag packaging. When a certain internal pressure is reached, e.g. due to the development of steam, the automatic pressure relief in the area of the bag head is released by releasing the pressure. The automatic overpressure relief can also be carried out by means of a tear-open aid, for example by means of a sealing seam between the jacket parts in the form of a tear-off tip directed towards the inside of the bag.

After the pressure relief and the required heating of the contents of the bag, the bag head seam can, if not done automatically, be opened or completely opened. This opens the bag so that the contents can be easily removed. If necessary, easy opening of the bag head seam can be additionally facilitated by a tear-open aid on the bag head seam.

Figures 1 and 1a and 2 exemplify two different embodiments of the bag packaging according to the invention.

Figure 1 shows the perspective view of a pre-folded plastic film (1). A V-shaped fold (2) is provided, for example, to design a base part. For example, a W-shaped fold can be used instead of a V-shaped one. The recesses (3) are made in the area of the V-shaped fold, here, for example, in a rectangular shape. When connecting the side seams, e.g. by sealing, touch and seal the front and back in the area of the hatched areas (4) and (4a) directly. As a result, when the volume of the bag increases, the seam in the area of the V-shaped fold cannot widen, which leads to the structural stability of the bag and to Training of a stand-up pouch contributes.

Tear tabs (5) are provided as examples on the front (1b) and the back (1a). The presence and design of these pull tabs are subject to change and are based on purpose and need. Instead of a pull tab, a carrying handle can also be provided, which can optionally also serve as a pull tab at the same time. The tear tab can also have at least one recess for hanging the bag packaging.

FIG. 1a shows a side view of a plastic film and tear strip joined to a bag according to FIG. 1.

The upper limit of the V-shaped fold (2) is indicated by a broken line, the recesses (3) and the surfaces (4) on which in the area of the V-shaped fold the front and back directly e.g. sealed, are indicated by hatching.

Via the side seams (1), the front and back of the plastic film (1) are connected to each other in a separable manner. The bevel seams (13) increase the stability of the bag and relieve the side seams (12), particularly in the area of the recesses (3). The bevel seams (13) relieve the lateral sealing seams in the area of the transition from the 2-layer to the 4-layer (area of the V-shaped bottom) bag part. Instead of the recesses 3, overlaps or tabs can also be provided.

In the region of the upper end of the bag, a top seam (14) extending over the entire width of the bag and, in particular, a sealed seam are expediently provided. The head seam (14) preferably has a tear-open aid (15), for example designed as a tear-open tip. The tear-open aid should be designed in such a way that its effect does not develop due to an increase in pressure in the bag, i.e. if the pressure in the closed bag increases, there should be no independent relief of excess pressure through a partial opening of the head seam (14), in particular in the area of the tear-open aid (15) . Therefore it is advisable for example to provide a marking tip with the tip pointing upwards. The pressure is usually built up by heating the contents, for example by microwave treatment in a closed bag, whereby water vapor develops, for example.
The side seams (12) are preferably slightly above the transverse head seam (14). This reduces the risk of the head seam tearing into the side seam.

The automatic overpressure relief (6) can be, for example, at least one recess (8) in at least one of the jacket surfaces, the recess (8) being completely sealed by a seal (7) which tightly connects the front and rear sides (16) of the jacket part, is surrounded. A recess (8) in the same geometric shape is preferably opposite each other in the front and back of the jacket part. The recess (8) is drawn as an example circular. Other geometric shapes, such as oval, polygonal, such as triangular, quadrangular, etc., can also be used. The automatic overpressure relief (6) is arranged in the area of the upper end of the bag and in particular close to the seam of the head bag. It is essential that the automatic overpressure relief (6) is arranged above the maximum filling level of the filling material in the bag, so that the filling material cannot escape through the recess (8).

A marking tip (15) is shown as an example in FIG. 1a. This configuration makes it possible to move the automatic overpressure relief far into the area of the upper end and thus to increase the maximum fill level.

As a rule, after the pressure has been released, the head seam (14) can be between the tear strip and the back of the bag, e.g. by hand, fully opened and the contents of the bag removed.

FIG. 2 shows the side view of a bag packaging made of a plastic film (21) folded in the bottom area. A V-shaped fold (22) forms the bottom of the bag.

The front and back of the bag are over the side seams (32) connected.

In the V-shaped fold (22) again recesses (23) are shown, which make it possible that the side seams of the front and back, in the area of the V-shaped fold, touch and are connected to each other. Furthermore, diagonal seams (33) are drawn in, which, as mentioned above, serve to improve the stability of a stand-up pouch and to relieve the side seams. The top seam (34) seals the back with the front of the bag due to its sealing connection.

An automatic overpressure relief (35) is shown as an example in the form of a tear-open tip. The tip expediently points towards the inside of the bag, which ensures that the pressure can be relieved at the intended point, the tear-off tip. When the pressure in the bag increases and the resulting volume expansion, the bag head seam at the tear-open point opens to the extent that pressure equalization can take place. It is then possible to open the bag over the entire bag head seam, for example by hand, and to remove the contents, provided that the entire bag head seam has not already opened.

Further modifications of the examples described above or other combinations of individual described features with one another are possible.

The parts of the bag, such as the front and back and, if appropriate, the base part, can be firmly connected via the tear-off layer attached to at least one side of the plastic film, or, even without a tear-off layer, by adhesive bonding.

Typical tear strengths of the sealed seams are greater than 5 N / 15 mm resp. the destruction of the bag next to the sealed seams, preferably tensile strengths greater than 20 N / 15 mm and in particular greater than 30 N / 15 mm.

The tensile strength of the seams in the case of sealed seams can be determined by the geometry of the sealing tool, the sealing pressure, the sealing temperature and / or the sealing time or, accordingly, by the amount of energy Ultrasonic welding or sealing can be influenced.

The sealed seams are expediently carried out using a tool with rounded edges. The sealing seams produced with such a tool have higher strengths than those which were produced with a sharp-edged tool. The latter can have a notch effect. However, this fact can be used to design the seal seams on the tear strip.

The sealing pressure depends on the material and the thickness of the plastic film and is typically 1 to 10 kg / cm² sealing area.

The sealing temperature also depends on the material and thickness and can range from 140 ° C to 240 ° C.

The sealing temperature is preferably 170 ° C to 220 ° C and in particular sealing temperatures of 180 ° C to 200 ° C are used.

The sealing is preferably controlled via the temperature and / or time.

In practice, the sealing time can be 0.3 to 3 seconds. be; a sealing time of 0.4 to 1 sec is preferred. and in particular from 0.5 to 0.8 sec.

The present invention also relates to the use of the pouch packaging according to the invention and in particular stand-up pouch packaging for packaging filling goods which are heated in particular by microwave treatment. Food and food preparations are primarily considered as filling goods. Such foods can preferably be in liquid, pasty, gelatinous or optionally in solid form or a mixture of these forms. Food preparations can likewise preferably be in liquid, pasty, gelatinous or, if appropriate, in solid or semi-solid form or represent mixtures of such forms. Furthermore, the food and food preparations can be filled into the bag packaging according to the invention in raw, semi-cooking or cooking form. The pouch packaging can be made, for example, aseptic or low-aseptic.

For example, this can be done by sterilization, such as radiation or preferably heat sterilization, pasteurization or hot filling. Other methods, such as chemical methods using preservatives, are also possible. In practice, the contents are filled into the open-ended bag packaging, the opening is sealed, for example by sealing, and the filled and closed bag packaging under counterpressure under the sterilization conditions, e.g. Warm to 121 ° C for 30 minutes, subjected. A bag packaging treated in this way can then be stored for longer periods. The filled and closed pouch packaging can be subjected to a microwave treatment in order to prepare the contents and in particular to reheat it. With increasing heat development and heating of the bag contents, the volume increases e.g. through steam development. When a certain internal pressure is reached, e.g. can be between 4 and 10 Pa, the pressure equalization takes place via the automatic pressure relief. Upon completion of the reheating procedure, all or part of the bag head seam can be easily, e.g. opened by hand.

The bags according to the invention are gastight and liquid-tight, i.e. H. After filling and closing, no more ingredients can come out of the bag, resp. Foreign substances get into the bag. The term gas-tightness is understood in particular to mean bags which, for example, have an oxygen diffusion of less than 10,000 cm³ / m² · day · atm, expediently less than 2,000 cm³ / m² · day · atm, preferably less than 100 cm³ / m² · atm Show day · atm and especially less than 10 cm³ / m² · day · atm.

Claims (8)

Bag packaging for fillings which can be heated by microwave treatment, comprising a jacket part or a jacket and a bottom part, made of flexible plastic film, the front and back of the jacket part and the bottom part being connected to one another by sealing seams,
characterized in that
the jacket part is formed from a plastic film which contains a tear-off layer on the inside and the bag packaging has a removal opening in the area of the upper end of the jacket part which is closed by a bag head seam, and the bag has an automatic overpressure relief in the area of the upper end. Bag packaging according to claim 1, characterized in that the automatic overpressure relief represents a tear-open aid on the bag head seam. Bag packaging according to claim 1, characterized in that the automatic overpressure relief is arranged within the area of the bag interior in the form of a tear-open opening. Bag packaging according to claim 3, characterized in that the automatic relief of pressure is arranged within the area of the bag interior and in the immediate vicinity of the head bag seam. Bag packaging according to claim 1, characterized in that the plastic film of the jacket part or the jacket and bottom part has a barrier layer against gases and vapors. Bag packaging according to claim 5, characterized in that the barrier layer is a ceramic layer. Bag packaging according to claim 1, characterized in that the flexible plastic film from the outside in a polyethylene terephthalate film with a thickness of 10 to 15 µm, an SiO _x layer, where x is a number from 1.2 to 1.7 and the layer thickness 10 to 100 nm, contains a further polyethylene terephthalate film with a layer thickness of 10 to 15 µm and a tear-off layer in the form of a 40 to 60 µm-thick PP film or a tear-off layer in the form of a 40 to 60 µm thick cPP film. Use of the bag packaging according to claim 1 for the packaging of filling goods which are reheated by microwave treatment.

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