DE2348931C3 - Method of manufacturing a body for moisture-impermeable packaging - Google Patents

Description

Recently, the requirements for highly moisture-impermeable packaging have increased for medical tablets, foodstuffs, sensitive machine parts and other moisture-sensitive goods.

From US-PS 33 31 495 a body made of a thermoplastic film with two or more bulges is known on the flat side with a Aluminum foil is covered and on the side having the bulges outside of an aluminum foil is encased, whereby the plastic film is completely connected to the aluminum foil

In US-PS 36 84 610 a method for producing a five-layer composite film is be wrote. A thermoplastic film is used on both sides coated with metal foils by means of adhesive interlayers

In DE-PS 5 88 953 a process for the production of both sides coated with metal foil is Cardboard container described in which one of the two metal foils is first applied with a vegetable glue the cardboard is glued on, while the other only after the pasted cardboard has completely dried out is glued on with a binding agent. As the cardboard is completely dry, there are no undesirable side effects such as blistering or cracks in the metal foil. In addition, flawless containers can be used shape when the a metal foil is applied with a binder and heated, as the metal foil on the The heated binding agent can be moved. This process creates fold-free boxes with smooth Revenge, but by no means produce moldings with indentations that are lined with recesses in a cut metal foil.

The production of "moisture-permeable bodies with only one indentation is, apart from Exceptional cases, not practically carried out, however, bodies for packaging with two or more, especially many indentations to accommodate the

Package contents widespread

In the known process for the production of moisture-impermeable body is generally a thermoplastic film, which is already for itself moisture-impermeable is z. B. a polyvinylchlo rid film, or a moisture-proof polyvinyl nyichloridfolie, or a moisture-impermeable finished thermoplastic film, z. B. a polyvinyl chloride film with polyvinylidene chloride in the form of a coating or film is covered until

* 5 softening heated, whereupon the softened film means Applying pressure or negative pressure to a moisture-impermeable body with one or more Indentations to accommodate the contents of the package are molded.

so These known processes are Stretch deformations, and these methods are therefore well applicable to those materials that are used in Heating and softening as thermoplastic films stretch 100 to 200 percent or more can.

However, it has not been possible to make the moisture-proof body with two or more Indentations to accommodate the contents of the package using a composite film len, which in a conventional manner by gluing a thermoplastic film and a metal foil has been produced as the metal foil in the course of Stretch forming tears.

The reason why this body is not after

conventional deformation methods can be produced, is that here the elasticity of the material to be deformed must be 100% or more, but only the maximum elongation of the metal foil

is about 20 to 30% even if the deformation is done in heat. Accordingly, the Metal foil destroyed during deformation

The invention is based on the object of a method for producing a moisture-impermeable Body with at least two indentations using a composite film to create the has been produced by gluing a thermoplastic film to a metal foil without the Metal foil is destroyed, with the occurrence of wrinkles in the area of curvature of the indentations should be avoided for taking up the contents of the package. This object is achieved according to the invention solved by the features in the characterizing part of claim 1

The approach disclosed in US Pat. No. 3,331,495 differs from the method according to the invention with regard to the means which ensure the impermeability of a molded article to moisture a thermoplastic film must be used. From the teaching of US-PS 33 31 495 and the other publications that are completely different from the subject of the application in terms of task and solution the solution of the problem was by no means obvious to the average person skilled in the art. Since a metal foil in a Stretching of more than 20 to 30% breaks, recesses that can be deformed without tearing can be cut into the metal foil, so the metal foil must be pre-cut. Is also none of the patents to infer that a deformation of recesses of a metal foil with With the help of a hot melt adhesive, the hot melt adhesive acts as a lubricant.

In the method of the invention, the surrounding edges of the recess areas of the metal foil are stretched with progressive deformation towards the center of the dies, since the hot melt adhesive is softened and the softened adhesive serves as a lubricant, and the surrounding edges the recess areas have already been cut. Therefore, the recess areas can be used without being destroyed the metal foil are stretch-deformed.

Examples of thermoplastic films that can be used in the process according to the invention, are foils made of polyvinyl chloride, polyethylene, polypropylene, polyesters or polycarbonates. Preferably Polyvinyl chloride films are used as thermoplastic films. The thickness of the thermoplastic films is generally 100 to 500 μ, preferably 150 to 300 μ and in particular 150 to 200 μ.

Examples of the metal foils which can be used in the process according to the invention are foils made of aluminum, Tin, copper or iron. Aluminum foils are preferred. The metal foils preferably have a Thickness of 30 to 150 μ, in particular 40 to 70 μ.

Preferably hot melt adhesives based on ethylene-vinyl acetate copolymers are used for the method of the invention, Polyvinyl acetate Polyvinyl butyral, polyethylene or polyamides used, these polymers as the main component r. B. with Colophony, ester gums or paraffin are mixed as additives. The thickness of the hot melt adhesive is preferably 3 to 30 μ, in particular 10 to 15 μ.

The occurrence of wrinkling or shrinking is effectively prevented if one is already familiar with the The composite foil provided with the incisions in the metal foil on the metal side with a further thermoplastic The film is glued and the five-layer composite film obtained in this way is subjected to stretching deformation the compressive force of the holding jaws or the sheet metal holder can be increased during the stretching deformation, so that the stretching deformation of the composite film without the occurrence of wrinkles or shrinkage is possible

For bonding the thermoplastic film to the metal film, an adhesive is preferably made of a

ίο saturated polyester resin or an adhesive made of saturated polyester / isocyanate is used. The thickness of this adhesive layer is preferably 3 to 30 μ, in particular 5 to 10 μ.
Due to the fact that the metal foil has already been cut, the gluing of the lowermost thermoplastic foil to the metal foil is carried out using a hot-melt adhesive. According to the invention, the metal foil can then be stretch-deformed without tearing. A hotmelt adhesive or normal adhesive can be used to bond the thermoplastic film to the surface of the metal film. If a hot-melt adhesive is used, both the hot-melt adhesive on the surface and the hot-melt adhesive on the rear side of the metal foil are softened at the time of stretching. Thus, the hot-melt adhesive on the rear side of the metal foil serves as a lubricant. The force applied when pressing the jaws or sheet metal holders together can be increased due to the presence of the thermoplastic film on the surface of the metal foil, and the occurrence of wrinkles or shrinkage in the edge or curvature area can be avoided. In the case of using the aforementioned "Vylon 300" or adhesive based on saturated polyesters and isocyanates, the metal foil and the thermoplastic foil are simultaneously deformed towards the center of the die during deformation Time of deformation to be reinforced. In addition, due to the fact that the force applied when compressing the jaws or sheet metal holders can be increased, there is no wrinkling or shrinkage in the edge or curvature area of the indentations described with reference to the drawings.

It shows

F i g. 1 shows a plan view of an embodiment of a composite film,

F i g. T. a section along the line II of FIG. 1,
F i g. 3 shows a plan view of a moisture-impermeable body with two indentations for receiving the package contents, which after the deformation of the parts shown in FIGS. 1 and 2 shown composite film has been obtained,

F i g. 4 shows a section along the line H-II in FIG. 3, Fig. 5 shows a cross section of a stretch forming machine, the mainly two punches and the corresponding die as well as the Zusiana of the composite film shows how it can be seen from FIGS. 1 and 2 results before the stretching deformation.

6 shows a cross section of a stretch forming machine, the mainly two punches and the corresponding die as well as the condition of the composite film shows after the stretching deformation,

F i g. 7 shows a cross section of another embodiment of a composite film;

F i g. 8 shows a plan view of a further embodiment of a composite film;

9 shows a section along the line IM-III in FIG. 8th.

Fig. 10 is a plan view of a moisture impermeable Body with two indentations to accommodate the contents of the package, which are after the Deformation of the composite film of Fig. 8 has been obtained,

11 shows a cross section along the line IV-IV of FIG Fig. 10,

Figure 12 shows a cross section of a further embodiment a composite film and

Fig. 13 is a cross-section of a package made using the moisture-impermeable Body with two indentations has been made. and which contains the package contents.

In Fig. 1 A represents a composite film in the state before stretch deformation, a thermoplastic film 1 being glued to a metal film 3 by means of a hot melt adhesive 2 and two recess areas A 'and A " consisting of cutting only the metal film 3, as indicated by the line Sin F. i g. 2 is indicated.

In the F i g. 3 and 4, A represents the moisture-impermeable body for the packaging, which has been obtained by stretching according to FIGS. 1 and 2. The body consists of a thermoplastic film I, a hot-melt adhesive 2, a metal film 3, the edge areas 4, indentations for receiving the package contents 5 and gaps 6, which are caused by the wandering of the peripheral edges of the two recess areas A ' and A "(see FIG. I) the metal foil 3 was created at the time of the stretching deformation. B denotes the cutting line of the metal foil 3.

In the following, the process of stretching deformation is described by the methods shown in FIGS. 1 and 2 shown Composite films for the in the F i g. 3 and 4 shown moisture-impermeable bodies with two indentations for recording the contents of the package based on FIG. 5 and 6, the main show the punch and die of the stretch forming machine.

In FIGS. 5 and 6, Λ represents a composite film. A jaw or a sheet metal holder 7 is used to prevent wrinkling or shrinkage. The stretch-forming machine contains a die 8 with a cooling device 10, a punch 9. a heating device 11 which is provided in the jaw 7, and a plate 12 as a support for the punch 9. The jaw 7 has a flat recess C in the lower part, to facilitate the stretching deformation.

When the method is carried out in practice, the composite film A is placed on the die 8, which is cooled by means of the cooling device 10. The recess areas A ' and A "of the composite film are arranged so that they are located under the punches 9 and 9. The composite film is arranged between the die 8 and the jaw 7, which is heated by the heating device 11. This prevents wrinkles from occurring In this case, a temperature is used for the deformation at which the hot-melt adhesive 2 and the thermoplastic film are softened.

As shown in FIG. 6, the stamps 9 and 9 connected to the plate 12 are then lowered, the recess areas A and .4 "of the composite film A being stretched. The stamps 9 and 9 are then raised again, and the moisture-impermeable body with two book hangers to take up the contents of the package is removed after the hot melt adhesive 2 has solidified.

Instead of the composite film described above, the composite film according to FIG. 7th be used.

In FIG. 7, the composite film consists of thermoplastic films 1 and Γ, the hot-melt adhesive 2, a metal foil 3 and an ordinary adhesive 13. The cutting line for producing the recess areas is denoted by β. In the case of the composite film, there is an advantage that the metal film 3 can be reinforced during and / or after the stretching deformation, since the thermoplastic film 1 is glued to the metal film 3.

Furthermore, the method can also be carried out with the composite film shown in FIGS will.

8 shows the composite film A in the state before the stretch deformation, which is obtained by the following method: A thermoplastic film 1 is bonded to a metal film 3 using a hot-melt adhesive, and only the metal film is applied, forming the recess areas A ' and A "cut into the metal foil, as shown by a broken line E and also a solid line B , and the thermoplastic film 15 is bonded to the surface of the metal foil 3 with an adhesive 14.

In FIGS. 10 and 11, A represents a moisture-impermeable body for packaging purposes, which is obtained by stretching the composite film of FIG. 8 and 9 is obtained. In the Fi g. 10 and 11, the body consists of a thermoplastic film I, a hot-melt adhesive 2, a metal foil 3, a hot-melt adhesive or ordinary adhesive 14, a thermoplastic film 15, an edge or curvature area 16, an indentation 17 for receiving the package contents and a Gap 18 which has arisen due to the migration of the peripheral edges of the two recess areas A 'and A ″ (cf. FIG. 8) of the metal foil 3 at the time of the stretching deformation. £ means the cutting line of the metal foil 3.

Furthermore, the method can also be carried out using a seven-layer composite film according to FIG Fig. 12 instead of the aforementioned, shown in Fig.9 Composite film.

In Fig. 12 consists of the body of a Thermop ¹ .istischen film 1, a hot melt adhesive 2, a metal foil 3, an ordinary adhesive 19, a thermoplastic film 20, a hot melt adhesive or ordinary adhesive 21 as well as a thermoplastic film 22 B, the cutting line of the metal foil to form the recess areas.

To produce a complete package using the produced body, ζ. Β a moisture-proof film in which a metal foil is coated with a heat-sealable adhesive, with the more moisture-proof Body glued for packaging purposes according to FIG. 13. The packaging of FIG. 13 consists of one piece thermoplastic film 1, a hot-melt adhesive 2, a metal foil 3, a heat-sealable adhesive 23 an edge or curvature area 24, an indentation for receiving the package contents 25

a gap 26 caused by the migration of the peripheral edges the two recess areas of the metal foil was created, a heat-sealable adhesive 27, one Metal foil 2t · and the contents 29.

The number is self-evident in the procedure the indentations are not restricted. Accordingly, the bodies produced can be a variety of FU indentations, in particular 100 or more indentations for taking up the contents of the package.

As mentioned earlier, the body is manufactured Impermeable to moisture, as the metal foil is not destroyed and no wrinkles or shrinkage occurs in the edge or curvature area of the indentations for receiving the package contents.

By cutting into the metal foil alone, recess areas are formed on the composite foil correspond in size to the contents of the package.

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a body with several indentations is obtained, which is lined with a wrinkle-free and non-torn metal foil. The edges of the metal foil at the gaps are still in the undeformed plane of the composite foil and can be covered directly with an aluminum foil so that it is impermeable to moisture. Each indentation is therefore completely surrounded by a metal foil, that is, completely protected from moisture. The opening of one indentation and removal of any agent has no consequences for the other indentations, since all indentations are separately surrounded and closed with a tetallic foil.

example 1

A hotmelt adhesive made from ethylene-vinyl acetate copolymer with a softening point of 60 to 70 ^° C. is applied in an amount of 15 g / m ² to a rigid polyvinyl chloride film with a thickness of 150 μ; then the coated PVC film is glued to a 60 μ thick, soft aluminum film. The aluminum surface of the three-layer composite film is coated with a heat-sealable vinyl chloride-vinyl acetate lacquer. Then only the aluminum foil is cut in such a way that two circular recess areas with a diameter of 24 mm are created.

Using a die with a clear width of 12.6 mm and a punch with an outer diameter of 12.0 mm, the composite film obtained is arranged between the die and the jaw, which, as shown in FIG. 5, is heated by a heating device . While the temperature of the die is kept below 50 ° C., the punch is pressed into the die, as shown in FIG As a result, the outer diameter of the recess areas of the soft aluminum foil is drawn to an outer diameter of 14 mm, and the hard PVC film is also stretch-deformed.

Example 2

Instead of the aluminum foil of Example 1, a soft aluminum foil is used μ with a thickness of 50 and is thick with the polyvinyl chloride, the μ 30, using a polyester

(saturated) / isocyanate adhesive bonded in place of the heat-sealable lacquer from example 1. Then will the rigid polyvinyl chloride film with a thickness of 150 μ glued to the aluminum surface using the hot melt adhesive from Example 1. With the so obtained composite film are both the polyvinyl chloride film with a thickness of 30 μ and the cut into soft aluminum foil with a thickness of 50 μ, so that circular recess areas

ίο arise with a diameter of 24 mm. the Recess areas of the composite film are in accordance with Example I stretched. A result similar to that in Example 1 is obtained.

Example 3

A hot-melt adhesive consisting of ethylene-vinyl acetate copolymer with a softening point of 60 to 7 (TC is applied in an amount of ^{10 g / m 2} to pinp hard vinyl vinyl film with a thickness of 150 μ. An aluminum foil with a thickness of 70 μ is then applied In the composite film obtained, only the aluminum foil is incised, so that two circular recess areas with a diameter of 24 mm are obtained.

The aluminum surface of the composite film consisting of three layers is then ^{coated with a polyester adhesive in an amount of 10 g / m 2} , whereupon a rigid polyvinyl chloride film with a thickness of 30 μ is formed to form one of five layers

jo existing composite film is glued on.

A die with a clear width of 12.6 mm and a punch with an outer diameter of 12.0 mm are used. The jaw is heated so that a temperature of 80 to 90 ⁰ C is maintained. At the time of deformation, the temperature of the die is kept at a temperature of below 50 ^° C. by means of cooling. The composite film is placed between the jaw and the die. During the deformation, the thermoplastic film and the hot-melt adhesive are softened, and two punches are pressed into the die, so that two indentations with a depth of 5 mm are created on the two recess areas of the composite film. As a result, the drawing reduces the outer diameter of the aluminum foil from 24 mm to 14 mm, and the rigid polyvinyl chloride sheet is stretch-deformed. The aluminum foil of the body obtained is not torn, and no wrinkling or shrinkage is observed in the edge or curvature area of the two indentations.

Example 4

Example 3 is replaced using a hot melt adhesive made of ethylene-vinyl acetate copolymer of the polyester adhesive repeated. Similar results as in Example 3 are obtained.

The moisture impermeability of the body obtained in Examples 3 and 4 with two indentations for receiving the contents of the packaging is only about '/ n that of a commercially available body of the same shape with the lowest moisture permeability. The known body is manufactured in such a way that one a polyvinyl chloride film with a thickness of 150 μ with polyvinylidene chloride resin in a thickness of 25 μ coated and glued with a similarly coated Poiyvinyichioridfoue

For this purpose 3 sheets of drawings

Claims (9)

Patent claims: 1. A method of manufacturing a body for moisture-proof packaging, the two or has more indentations for receiving the contents of the package and one with one Metal foil covered thermoplastic film, characterized in that you first glue the metal foil to the thermoplastic film with a hot melt adhesive on the obtained composite film by cutting only the metal foil two or more recess areas forms, which correspond to the size of the package contents, and the recess areas of the composite film at a temperature at which the The hotmelt adhesive and the thermoplastic film soften, stretch-deformed to form the indentations 2. The method according to claim 1, characterized in that the already with the incisions in the metal foil provided composite foil on the metal side with a further thermoplastic The film is glued and the five-layer composite film obtained in this way is subjected to stretching deformation. 3. The method according to claim 1 or 2, characterized in that the thermoplastic film a film made of polyvinyl chloride, polyethylene, polypropylene, polyester or polycarbonate is used 4. The method according to claim 3, characterized in that ma.ι thermoplastic films with a Thickness from 100 to 500 μ, preferably 150 to 300 μ and in particular 150 to 200 μ used. 5. The method according to claim 1 of 2, characterized in that a metal foil is made Aluminum, tin, copper or iron are used 6. The method according to claim 5, characterized in that metal foils with a thickness of 30 to 150 μ, preferably 40 to 70 μ used. 7. The method according to claim 1 or 2, characterized in that there is a hot melt adhesive used, the main component of ethylene-vinyl acetate copolymers, polyvinyl acetate, polyvinyl butyral, polyethylene or polyamides and as Contains additives colophony, ester gums or paraffin. 8. The method according to claim 7, characterized in that the hot melt adhesive in a thickness from 3 to 30 μ, preferably 10 to 15 μ, used. 9. The method according to claim 2, characterized in that the provided without incisions five-layer composite film provided with incisions, one of the thermoplastic films and the Penetrate metal foil, and the surface of the incised thermoplastic film underneath Use of a hot melt adhesive or an ordinary adhesive bonded to another thermoplastic film, and the resulting seven-layer composite film subjected to stretch deformation.