GB2415407A - Cover for sealing food containers - Google Patents

Cover for sealing food containers Download PDF

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Publication number
GB2415407A
GB2415407A GB0512958A GB0512958A GB2415407A GB 2415407 A GB2415407 A GB 2415407A GB 0512958 A GB0512958 A GB 0512958A GB 0512958 A GB0512958 A GB 0512958A GB 2415407 A GB2415407 A GB 2415407A
Authority
GB
United Kingdom
Prior art keywords
layer
cover
sealing
polyester
cover according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB0512958A
Other versions
GB0512958D0 (en
GB2415407B (en
Inventor
Christian Richter
Helmut Resch
Franz Reiterer
Andreas Niederer
Markus Fellner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Teich AG
Original Assignee
Teich AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Teich AG filed Critical Teich AG
Publication of GB0512958D0 publication Critical patent/GB0512958D0/en
Publication of GB2415407A publication Critical patent/GB2415407A/en
Application granted granted Critical
Publication of GB2415407B publication Critical patent/GB2415407B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
    • B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
    • B32B3/30—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by a layer formed with recesses or projections, e.g. hollows, grooves, protuberances, ribs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B32B27/10—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of paper or cardboard
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/34—Layered products comprising a layer of synthetic resin comprising polyamides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
    • B65D65/38—Packaging materials of special type or form
    • B65D65/40—Applications of laminates for particular packaging purposes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2250/00—Layers arrangement
    • B32B2250/40—Symmetrical or sandwich layers, e.g. ABA, ABCBA, ABCCBA
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2367/00—Polyesters, e.g. PET, i.e. polyethylene terephthalate
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2391/00—Waxes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2439/00—Containers; Receptacles
    • B32B2439/70—Food packaging

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Laminated Bodies (AREA)

Abstract

A cover 1 for sealing food containers comprises an at least triple layer support material 2, which is provided with a sealing material 5 on its side facing the container. The support material is a symmetrical composite with a core layer of paper and polyester layers 4, 4' applied to this on both sides. The sealing layer e.g. wax may have surface roughened areas 12 or a surface roughened pattern 13. This composite is metal free and can thus be checked for severe damage in a simple manner by any detection device. In addition as a result of the symmetrical structure, the occurrence of internal stresses (dishing) usual in plastics is hindered, and this is also achieved by stepwise cross-linkage and stretching during storage. The cover is microwave safe.

Description

J
1 241 5407 Sealing Cover The invention relates to a cover for sealing food containers with an at least triple- layered support material, which is provided with a sealing layer on its side facing the container. The invention additionally relates to a process for the production of the aforementioned cover.
It is known to produce covers for sealing food containers from aluminium foils, since these are easily processed, i.e. punched to form covers, and moreover, after the containers have been sealed, satisfactorily protect the foodstuffs stored therein against the entry of air or contaminants. Since the aluminium foils used are also relatively thin, they have the disadvantage that the aluminium covers can be destroyed either unintentionally or intentionally. This is achieved, for example, by the surface of the aluminium foil being slit during transport, i.e. unintentionally after purchase of the food containers or intentionally by tampering. In this case foreign objects such as nails have been inserted through the slits in the surface to enable money to be extorted from the food chains or manufacturers after tampering. As a result, there has been a move towards providing detection devices on store shelves or at the check-out counters to enable these acts of tampering to be tracked. However, as these detection devices generally react to metal, it is not possible to satisfactorily detect foreign objects in the foodstuffs when aluminium foils are used. The invention intends to remedy this.
Therefore, according to the invention, a cover of the aforementioned type is proposed, which is characterised in that the support material is a symmetrical composite with a core layer of paper and polyester layers attached thereto on both sides. Advantageous configurations of the cover according to the invention are disclosed according to sub- claims.
The invention additionally relates to a process for the production of the aforementioned cover, which is characterised in that an adhesive is applied to the first surface of a paper layer and a polyester foil is laminated on this, wherein in a further laminating step after initial cross-linkage a further polyester foil is applied to the second surface of the paper layer.
Further configurations of the process according to the invention are disclosed according to sub-claims.
The invention shall be explained in further detail below on the basis of Figures 1 and 2 and also on the basis of practical examples. In this case, Figure 1 shows a possible embodiment of the cover according to the invention using an untreated polyester foil 4 in the support material 2, whereas according to Figure 2 a chemically and/or physically pretreated polyester foil 4' is used.
To produce a cover 1 according to the invention, as shown in accordance with Figure 1, an adhesive layer 7 is applied to both sides of a paper layer 3, which has a grammage of 40 g/m2, for example. In this case, it has been found that the addition of white pigments to each adhesive layer facing the printer's varnish layer 6 provides a particular brilliance in the finished imprint 11. A polyester layer 4, preferably of polyethylene terephthalate, is then laminated on the first surface of the paper layer 3 and pressed onto this. This preliminary composite is then stored for about 48 hours to achieve an initial cross-linkage of the adhesive 7. In a further laminating step a further adhesive layer 7 is applied to the second surface of the paper layer 3 and also a polyester layer 4 is applied to this by cold pressing. To produce the support material 2 in the form of the composite, this is stored at room temperature for at least one week to achieve a complete cross-linkage of the composite in the form of the support material 2.
To prevent the known dishing in plastics, i.e. changes to their shape as a result of internal stresses, the composite in the form of the support material 2 is stretched into plastic foils, for example, during storage. These instances of dishing are prevented by the pressure exertion of the stretch foil. Moreover, the entry of moisture from the air is prevented by We stretch foils made of plastics.
The printer's varnish layer 6 or sealing layer 5 can subsequently be applied to the support material 2. For better adhesion in this case, a pore filler layer 10 or otherwise a primer layer 8 is applied using application rollers. A usual imprint 11 arranged to face the observer is then generated by means of pressing rollers, whereas a sealing layer 9 is applied to the primer layer 8. By selection of the pressing rollers, a surface roughened pattern can be achieved both on the printer's varnish layer 6 and on the sealing layer 5. The configuration of a surface roughened pattern in the sealing wax layer S is particularly advantageous in this case to allow covers that are usually stored in punched out form after production to be unstacked. Preformed pressing rollers are used in this case, for example, which allow the generation of surface roughened areas in the form of spacers 12. The air enclosed between the spacers 12 enables the cover elements in the stack to slide relative to one another so that they can be easily lifted off each another during unstacking. However, it is also possible to provide a surface roughened stamp pattern 13 in the sealing wax layer 5 by appropriate roll embossing.
A further advantageous configuration is shown in Figure 2, wherein chemically and/or physically pretreated polyester foils 4' are used. The chemical pretreatment can be achieved, for example, by coextrusion of the polyester foils with copolymers adhering to these or by physical methods such as etching. This increases the adhesion of the polyester foils 4' in such a way that the additional bonding materials such as the printer's varnish 10 and the primer 8 can be omitted. This enables a simplified procedure in the production of the cover according to the invention while retaining uniform stable properties.
The stability of the cover according to the invention in relation to destruction is achieved on the basis of a test of the puncturing resistance of surface-punched plates with a diameter of 95.5 mm compared to known aluminium covers with a thickness of 1lm. In this case, the samples are subjected to a bolt with a weight of 66.4 g with an impact surface of 6 mm in diameter. This bolt is attached to a column with centimetre display so that the respective drop height can be adjusted and also measured by way of this column. It has been revealed in this case that the known aluminium covers were punctured after being subjected to the bolt at a drop height of only 15 cm.
However, with the covers according to the invention the drop height amounted to 35 cm so that destruction of the covers was indicated when subjected to the aforementioned weight units. As a result of this, it can be shown that the covers according to the invention exhibit a higher mechanical load capacity than the aluminium covers known per se.
In summary, it can be shown that the cover element according to the invention meets the requirements for material properties since this has a symmetrical structure in its support material, which is achieved by generating a symmetrical composite between a core layer of paper and polyester layers attached to this on both sides. This composite is metalfree and can thus be easily checked for severe damages by any detection devices provided. In addition, as a result of the symmetrical structure, the occurrence of internal stresses (dishing) usual in plastics is hindered, and this is also achieved by the procedure according to the invention, namely the stepwise cross-linkage of the composite structures. The cover according to the invention is suitable for sealing food containers and is moreover microwave-safe.
List of Reference Numerals I cover 2 support material 3 core layer/paper 4, 4' polyester layers (pretreated) sealing layer 6 printer's varnish layer 7 adhesive 8 primer 9 sealing wax pore filler I I imprint 1 2 spacer 13 surface roughened stamp pattern

Claims (25)

  1. Patent Claims 1. Cover (1) for sealing food containers with an at least
    triple-layer support material (2), which is provided with a sealing layer (5) on its side facing the container, characterised in that the support material (2) is a symmetrical composite with a core layer of paper (3) and polyester layers (4, 4') attached thereto on both sides.
  2. 2. Cover according to Claim 1, characterised in that the polyester layers (4, 4') are made of polyethylene terephthalate.
  3. 3. Cover according to Claim 1 or 2, characterised in that the polyesters used in the polyester layers (4, 4') are chemically and/or physically pretreated on one or both surfaces.
  4. 4. Cover according to one of Claims 1 to 3, characterised in that the mass per unit area of the core layer of paper (3) lies in a range of 20g/m2.
  5. 5. Cover according to one of Claims 1 to 4, characterised in that the thickness of the polyester layers (4, 4') lies in a range of 8-50 1lm.
  6. 6. Cover according to one of Claims 1 to 5, characterised in that the sealing layer (5) is a co-extrudate with the adjoining polyester layer (4, 4').
  7. 7. Cover according to one of Claims 1 to 5, characterised in that the sealing layer (5) is made of sealing wax.
  8. 8. Cover according to one of Claims 1 to 7, characterised in that the sealing layer (5) is stamped to be surface roughened.
  9. 9. Cover according to one of Claims 1 to 7, characterised in that the sealing layer (5) has a surface roughened imprint.
  10. 10. Cover according to Claim 9, characterised in that the surface roughened imprint is provided in the form of geometrically arranged spacers (12).
  11. 11. Cover according to one of Claims 1 to 10, characterised in that the cover (1) has an imprint (11) on the side remote from the container.
  12. 12. Cover according to one of Claims 1 to 1 1, characterised in that this is microwave-safe.
  13. 13. Process for the production of a cover according to one of Claims 1 to 12, characterised in that an adhesive (7) is applied to the first surface of a paper layer (3) and a polyester foil (4, 4') is laminated on this, wherein in a further laminating step after initial cross-linkage a further polyester foil (4, 4') is applied to the second surface of the paper layer (3) by means of an adhesive layer (7).
  14. 14. Process according to Claim 13, characterised in that a polyethylene terephthalate is used as polyester.
  15. 15. Process according to Claim 13 or 14, characterised in that the polyester is chemically and/or physically pretreated on one or both surfaces.
  16. 16. Process according to one of Claims 13 to IS, characterised in that paper with a mass per unit area of 20-80 g/m2 is used for production of the support material (2).
  17. 17. Process according to one of Claims 13 to 16, characterised in that polyester foils (4, 4') with a layer thickness of 8-50 Am are used for production of the support material (2) .
  18. 18. Process according to one of Claims 13 to 17, characterised in that the sealing layer (5) is applied onto the polyester layer (4, 4') facing the container by co- extrusion.
  19. 19. Process for the production of a cover according to one of Claims 13 to 18, characterized in that the sealing layer (5) is applied by painting on a sealing wax (9).
  20. 20. Process according to one of Claims 13 to 19, characterized in that the sealing wax layer (9) is surface roughened by means of roll embossing.
  21. 21. Process according to one of Claims 13 to 20, characterized in that the sealing wax is applied by means of cup embossing in surface roughened form, preferably in the form of surface roughened spacers (12).
  22. 22. Process for the production of a cover according to one of Claims 13 to 21, characterized in that a decorative imprint (11) is applied to the side of the support material (2) remote from the container.
  23. 23. A cover substantially as hereinbefore described with reference to Figure 1 of the attached drawings.
  24. 24. A cover substantially as hereinbefore described with reference to Figure 2 of the attached drawings.
  25. 25. A process for the production of a cover for sealing food containers substantially as hereinbefore described with reference to Figure 1 and/or Figure 2 of the attached drawings.
GB0512958A 2004-06-24 2005-06-24 Sealing cover Expired - Fee Related GB2415407B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT4422004 2004-06-24

Publications (3)

Publication Number Publication Date
GB0512958D0 GB0512958D0 (en) 2005-08-03
GB2415407A true GB2415407A (en) 2005-12-28
GB2415407B GB2415407B (en) 2009-04-29

Family

ID=34842257

Family Applications (1)

Application Number Title Priority Date Filing Date
GB0512958A Expired - Fee Related GB2415407B (en) 2004-06-24 2005-06-24 Sealing cover

Country Status (1)

Country Link
GB (1) GB2415407B (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1536556A (en) * 1974-12-17 1978-12-20 Trentesaux Toulemonde Sa Heat sealable multi-layer sheet
EP0687636A1 (en) * 1994-06-15 1995-12-20 Du Pont De Nemours International S.A. Lid for container
JPH0948468A (en) * 1995-08-07 1997-02-18 Dainippon Printing Co Ltd Lid material
US6440530B1 (en) * 1998-12-16 2002-08-27 Alcan Technology & Management Ltd. Lids for closing off containers
JP2004196381A (en) * 2002-12-20 2004-07-15 Toppan Printing Co Ltd Lid material

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1536556A (en) * 1974-12-17 1978-12-20 Trentesaux Toulemonde Sa Heat sealable multi-layer sheet
EP0687636A1 (en) * 1994-06-15 1995-12-20 Du Pont De Nemours International S.A. Lid for container
JPH0948468A (en) * 1995-08-07 1997-02-18 Dainippon Printing Co Ltd Lid material
US6440530B1 (en) * 1998-12-16 2002-08-27 Alcan Technology & Management Ltd. Lids for closing off containers
JP2004196381A (en) * 2002-12-20 2004-07-15 Toppan Printing Co Ltd Lid material

Also Published As

Publication number Publication date
GB0512958D0 (en) 2005-08-03
GB2415407B (en) 2009-04-29

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 20190624