JPH04242560A - Sealable laminate, pack made of said laminate and manufacture of said laminate - Google Patents

Abstract

PURPOSE: To resolve some problems in storing and transportation of a cooked pizza and other foods requiring a certain degree of thermal insulating characteristic and a mechanical shock-resistance. CONSTITUTION: This sealing laminate is used for packaging a cooked pizza and other products. This laminate comprises a laminate including a metallic layer 13, an intermediate polymer layer 15 and a formed web 14 having a gas cushion valve.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to packaging materials, and more particularly to packaging materials suitable for making packs with sealing and cushioning properties.

0002

BACKGROUND OF THE INVENTION Prepared pizzas for home delivery or customer pick-up at a store are often packaged in shallow cardboard boxes with cover openings or in envelope-shaped packs for delivery to customers. ing. The corrugated pleated box provides little thermal insulation to keep the pizza warm. Envelope packs are relatively expensive, so after they are distributed and the pizzas are removed, the packs are returned to the restaurant for reuse.

[0003] It is therefore desirable to provide inexpensive and insulating containers for the storage and delivery of cooked pizza and other food products or non-food products that require thermal insulation.

[0004] It would also be desirable to provide a container that can be distributed directly with the loaded food product and that can remain in the customer's possession.

[0005] Further desired properties of such a container are:
While some resistance to mechanical shock protects the products contained within the pack, it must also withstand tampering during transport and delivery of the contained items.

The present invention solves problems in the storage and transportation of cooked pizza, other food products, and non-food products that require some degree of thermal insulation and mechanical impact resistance.

US Pat. No. 4,576,669 (Ca.
(Puto) discloses an apparatus and method for manufacturing air cushion materials. In this case, a first membrane is heated and then thermoformed on a cooling roll having a cavity therein, and a second membrane is heated on a heating roll and then heat sealed to the first membrane. .

US Pat. No. 4,579,516 (Ca.
U.S. Pat. No. 4,576,669 discloses a forming roll used as a cooling roll for thermoforming the first thin film described in US Pat. No. 4,576,669.

US Pat. No. 4,192,669 (Le
Wicki et al. disclose a method of manufacturing an expanded cellular assembly of plastic material, which plastic material includes the use of multiple sheet materials.

US Pat. No. 4,415,398 (Ot.
Taviano discloses an air cell cushion dunnage formed from two sheets of flexible plastic material, one of which has already been embossed to define cells with trapped air. There is.

US Pat. No. 3,508,992 (Ch.
avannes) discloses a method of manufacturing a cellular material using multiple laminates, at least one of the laminates being embossed prior to sealing the laminates together.

US Pat. No. 3,142,599 (Ch.
avannes) discloses a stacked cushioning material and method for manufacturing hemispherical sealed elements.

US Pat. No. 3,208,898 (Ch.
avannes et al.) includes an embossed or molded plastic layer, a sealing layer, and a plurality of cells, and a second sealing layer is sealed on top of the cells. Discloses the items that were purchased.

US Pat. No. 3,285,793 (Ch.
Avanes discloses an embossed cushion material made by bonding two thin films of plastic, one of the thin films being embossed into a hemispherical shape.

US Pat. No. 3,586,565 (Fi
elding) discloses sealing a first sheet to a second embossed sheet to create a plurality of hemispherical sealed cells.

US Pat. No. 3,616,155 (Ch.
avannes) discloses a cellular product formed by stacking laminates. At least one of the laminates is embossed and the other laminate seals the embossed member. Each laminate has a plastic base and a gas-impermeable coating.

US Pat. No. 2,020,639 (Gr.
Ayson et al. disclose a sealed cardboard having a skeleton structure composed of a cell system filled with a fibrous insulating material.

Canadian Patent No. 1,191,437 (O
ttaviano discloses a cushioned dunnage material comprising a first single membrane layer embossed to form air cells therein and a second membrane adhered to the first membrane. ing.

Canadian Patent No. 1,186,204 (O
ttaviano) comprises a first multilayer thin film embossed to form air cells therein;
A cushioned dunnage material is disclosed comprising a second membrane adhered to the membrane.

British Patent No. 908,579 discloses a laminated multi-cell sheet packaging material. The material is made up of a first web embossed on an embossing drum and a second web adhered to the first web.

[0021] US Pat. No. 4,181,548 (We
(ingarten) discloses a three-layer stacked plastic cushioning material comprising: on either side of a central layer;
It has a flat central layer containing sealed air pockets.

US Pat. No. 4,855,186 (Gr.
olig et al.) disclose a transport plastic film having a first insulating layer adhered to the transport film and a heat reflective metal layer adhered to the first insulating layer.

[0023] International application WO 82/00020 (Nel
son-Ashley et al.) describe bonding a linear low-density polyethylene film to a metal sheet or metal box by engaging the film and the metal sheet, heating at least the metal sheet, and then applying pressure to the opposing free surfaces. Disclosed. This item can also be folded to make a pack.

French Patent Summary No. FR 2618382
No.-A discloses a packaging material made by adhering a layer of heat-shrinkable plastic material to a metal layer, preferably aluminum foil. The preferred heat shrinkable layer is polyethylene.

[0025]Sournal of Applied
Polymer Science, Volume 37
, No. 5, February 5, 1989 issue, 1183-11
Hjertberg, Sultan and So on page 95.
rvik describes the effect of corona discharge treatment of ethylene copolymers on the adhesion of this material to aluminum. Ethylene copolymers containing vinyl acetate are examples of polyolefins with increased adhesion.

[0026]Sournal of Applied
Polymer Science, Volume 37
, No. 5, February 5, 1989 issue, 1287-12
On page 97, Hjertberg and Lako disclose the effect of different functional groups on the adhesion between polyethylene containing ethylene co-vinyl acetate and aluminum foil.

[0027]

SUMMARY OF THE INVENTION The present invention is a hermetic laminate that includes a metal layer, an intermediate polymer layer adhered to the inner surface of the metal layer, and a molded web with gas cushion bubbles adhered to the intermediate layer. be.

The invention also includes packs made from the hermetic laminate.

The method for producing a hermetic laminate includes a step of heating a formed web, a step of feeding the heated formed web to an embossing roll, and a step of subjecting the heated formed web to a vacuum treatment with respect to the embossing roll. and vacuum treating the heated formed web to form bubbles within the thin film, such that the air in the bubbles in the formed web is trapped between the formed web and the laminate. bonding the laminate of the metal layer and the polymer layer to the laminate.

[0030]

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be explained in more detail with reference to the accompanying drawings, in which: FIG.

Referring to FIG. 1, a hermetic pack 10 is made from a hermetic laminate 8 (see also FIG. 4), which includes an outer layer 12 of laminate having an outer metal layer and an inner polymer layer. . Glued to this laminate is a molded web 14 with gas cushion bubbles. After folding along the fold line 20 to form the pack 10, the hermetic laminate 8 is sealed along the bottom seal 22 and side seals 24. A flap 16 extends beyond the mouth of the pack and is optionally provided with a sealing strip 18 for closing the sealing flap after loading a food product such as pizza (not shown).

FIG. 2 shows the hermetic pack 10 with the flap 16 in the closed position.

FIG. 3 shows the pack 10 with the top portion of the pack cut away to reveal the insert 32. The insert is optionally used in combination with an occlusive pack 10 to avoid direct contact of the cooked food product, such as pizza, with the formation of the gas-cushioned bubble web 14 of the pack.

The metal layer 13 of the hermetic laminate provides thermal insulation for the charged product, and the formed web 14 of gas cushion bubbles provides resistance to tampering during storage and handling.

FIG. 4 is a schematic cross-section of a preferred hermetic laminate 8 of the present invention.

Outer laminate 12 includes a metal layer 13 and an intermediate polymer layer 15. By corona treating the surface of the intermediate layer 15 in order to adhere it to the metal layer 13,
These layers are preferably adhered to each other.

The intermediate layer 15 may be monolayer or multilayer in construction, preferably a layer of ethylene vinyl acetate copolymer or layer 1 which will be in contact with the metal layer 13.
5 is another material layer whose surface can be corona treated. Various polymeric resins may be used to produce the intermediate layer 15, such as polyethylene with linearly low density, polypropylene, polyether block amide copolymers, polyamides, vinylidene chloride copolymers, and chemically modified Chemically modified ethylene copolymers such as ethylene vinyl acetate copolymers.

[0038] The metal layer 13 is preferably aluminum,
Aluminum foils or sheets of various thicknesses, or non-metallic substrates to which a metal layer or coating has already been applied or otherwise adhered. Such metal/polymer layer laminates are more particularly described in co-pending application US Pat. No. 449,617, which is incorporated by reference into this application. The laminate compositions and techniques of the co-pending application are still suitable for the present invention.

Molded web 14 may also include a single layer or multiple layers, and preferably includes a polyamide layer such as nylon 6. More preferably the nylon is such that it is adhered to the outer tamper resistant layer and the inner sealant layer via an intermediate adhesive layer. Ethylene polymers and copolymers are suitable for construction of the formed web 14, and ethylene alpha olefin copolymers can be used as linear low density polyethylene and very low density polyethylene.

FIG. 5 shows a schematic diagram of the apparatus and method for manufacturing the hermetic laminate of the present invention. Formed web 14 starts from roll 50 and passes to connection roll 52, preheat roll 54, and then to vacuum roll 56. The vacuum roll includes
A hemispherical cavity 58 is provided to form a bubble in the final laminate. Devices for this purpose are well known in the prior art, eg U.S. Pat.
No. 6,669 and No. 4,579,516.

Bubble density (ie, number of bubbles per unit area) and bubble dimensions (ie, bubble height) can be designed according to the desired end use. For cooked pizza, a bubble height of 3/16 inch is preferred, but greater than or equal to 1/2 inch or less than 3/16 inch is also acceptable.

Outer laminate 12 of FIG. 4 is fed off roll 60 and bonded to forming web 14 after bubbles are formed on the forming web. heated sandwich roll 6
2 selectively presses against the outer laminate 12 as it adheres to the forming web 14. This operation facilitates the lamination process.

One or more additional layers may optionally be laminated to forming web 14, to outer laminate 12 (along the metal surface of metal layer 13), or to both. For example, the formed web 14 is actually placed between the bonding layers of polymer layers, so in the final pack the formed web with the gas cushion bubble will not be the innermost part of the hermetic laminate.

Although the present invention has been described with reference to preferred embodiments, those skilled in the art will appreciate the gist of the invention with respect to sealable laminates, packs made from the laminates, and methods of making sealable laminates. Modifications may be made without departing from the scope of the claims.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a hermetic pack of the present invention.

2 is a plan view of the pack of FIG. 1 with the flap closed; FIG.

FIG. 3 is a plan view of the pack of the invention with the upper part of the pack cut away to show the inserts for holding the items carried in the pack;

FIG. 4 is a schematic cross-sectional view of a laminate of the invention.

FIG. 5 is a schematic diagram of the apparatus for the laminate manufacturing method of the present invention.

[Explanation of symbols]

8 Sealing laminate 10 Sealed pack 12 Outer layer 13 Metal layer 14 Molded web 15 Intermediate polymer layer 16 Flap 18 Seal strip 32 Insert

Claims (9)

[Claims] 1. A hermetic laminate comprising a metal layer, an intermediate polymer layer adhered to the inner surface of the metal layer, and a molded web with gas cushion bubbles adhered to the intermediate layer. 2. The hermetic laminate of claim 1 further comprising an additional polymer layer adhered to the inner surface of the formed web. 3. The hermetic laminate of claim 1 further comprising an additional polymer layer adhered to the outer surface of the metal layer. 4. The hermetic laminate of claim 1, wherein the intermediate polymer layer comprises a surface layer of ethylene vinyl acetate copolymer. 5. The intermediate polymeric layer comprises a layer of polymeric material selected from the group consisting of linear low density polyethylene, polypropylene, polyether block amide copolymers, polyamides, saran, and chemically modified ethylene vinyl acetate copolymers. The hermetic laminate of claim 1 comprising: 6. A pack made from a hermetic laminate according to claim 1, which is sealed to itself to form a container. 7. A method of manufacturing a hermetic laminate, comprising: heating a formed web; feeding the heated formed web to an embossing roll; and applying a vacuum to the embossing roll of the heated formed web. processing and vacuum treatment of the heated formed web to form bubbles within the thin film;
A method comprising adhering a laminate of a metal layer and a polymer layer to a formed web such that air in bubbles in the formed web is trapped between the formed web and the laminate. 8. The method of claim 7, further comprising the step of bonding the metal layer and the polymer layer together. 9. The surface of the polymer layer is corona treated,
9. The method of claim 8, wherein the treated surface is also brought into contact with the surface of the metal layer.