NL8503549A - FOLDABLE CONTAINER MADE OF ETHYLENE-PROPYLENE-COPOLYMER. - Google Patents

Description

V.0.7543

Collapsible container made from ethylene-propylene copolymer.

The present invention generally relates to the technique of manufacturing containers and more particularly relates to a collapsible administration container having a laminated wall construction in its body portion, permeation and absorption of the product, as well as oxygen absorption in all sensitive areas of the container structure are substantially prevented.

Collapsible tubes made of metal and plastic materials have long been known in the field of packaging, Extruded metal tubes are naturally brittle and repeated use often results in wall cracks, so that from another location, the essentially rigid delivery opening product is separated. Of the metal tubes known in the art, aluminum tubes, although probably the least brittle, have been somewhat limited in their applications, as hitherto it has not been possible to achieve a completely satisfactory on their internal surfaces. apply a coating when required to prevent attack and corrosion of the metal by an alkaline or acidic content, as well as contamination of the content by reaction products. Despite the relatively brittle nature of a metal tube, the said interior coating operation necessitates an additional processing step, which necessarily increases the price of the final article.

Tubes formed from polyethylene and other plastics have had widespread commercial success in packaging many products, however, when certain other products were contained therein, they were found to deteriorate in quality after some time.

Plastics, such as polyethylene, for example, are permeable to a certain extent when used in the wall thicknesses used for tubular containers, and of the essential oils present in most flavoring dentifrices, the volume is increased during storage of the container is smaller, making the dentifrice less pleasant in taste. Also, the plastic container wall absorbs oxygen for a certain period of time and can finally decompose the product, which has actually been found to be the case with fluoride-containing toothpaste. Another drawback of a 35 plastic tube lies in the inability of the surface to press “T” Γ * ** Γ * / Λ

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• * 4 -2- material and decorative material easy to absorb. In addition, plastic tubes, for example those made of polyethylene, have a memory effect; that is, when squeezed, they do not remain compressed, which is a particular drawback for dentifrice tubes.

To counteract the above-mentioned problems, it has therefore been proposed to provide a metal foil as a barrier between the product and the polyethylene tube body. This would counteract the compressibility problem in that the metal layer would impose its compressibility on the plastic. In addition, the metal foil barrier between the product and the polyethylene tube body would prevent said essential oil loss and oxygen absorption. It has been proposed to design the metal barrier as an intermediate layer between coating layers of polyethylene and to form a laminate thereof by heat with or without suitable adhesives. However, although a structure of this general character is effective in preventing any product permeation and oxygen absorption through the tube body, and especially when the inner thermoplastic layer is a copolymer of ethylene and a copolymerizable therewith monomer with a polar group, the possibility of product degradation persists, although to a much lesser extent.

Attention is drawn to the following state of the art.

US-A-3,295,725 discloses a tube in which the above-mentioned advantages of an aluminum tube are combined with the advantages of a plastic tube. This tube is a laminated, collapsible administration container, containing both a metal barrier and a polyethylene inner wall. The thermoplastic layer is generally described as consisting of polyolefin and a copolymer of an olefin and a polar group-containing monomer which is copolymerizable therewith. This laminate overcomes the limitations described above except for absorption of the essential oils from the dentifrices.

Canadian Patent 728,525 discloses a laminated tube containing an inner layer of polyethylene. This acknowledged the 3403343 * -3 problem of flavoring oil absorption by the thermoplastic wall.

U.S. Patent 4,096,946 discloses a laminated package using polyvinylidene chloride as the inner layer 5 and an outer layer of copolymer of ethylene and propylene. However, this packaging is not a tube; it contains no metal; and there is no mention of the properties of the copolymer as a flavoring barrier.

U.S. Patent 4,207,363 discloses a laminated film 10 which is used for packaging meats, which film contains a propylene-ethylene copolymer as the outer layer. This laminate is not a tube either; it does not contain metal; and this patent does not disclose the properties of the copolymer as a flavor barrier.

In addition, U.S. Patents 4,405,677, 4,308,084 and 4,279,344 disclose laminated packaging articles containing ethylene-propylene copolymer. None of these articles, however, were tubes and no mention was made of the properties of the copolymer as a flavor barrier.

It is therefore an important object of the present invention to provide a collapsible administration container with a laminated wall construction in the body portion.

Another object of the invention is to provide a tubular container wherein its body portion contains a plurality of adhesive layers, one of said layers providing a barrier against product migration and oxygen absorption, such as a metal foil, and other such layers consist of ethylene-propylene copolymer or a mixture thereof, which varies in density and crystallinity. The latter layer is used as an inner layer and preferably also as an outer layer, with various additional laminae interposed therebetween.

Such additional layers include paper and suitable adhesives. adhesives, such as a copolymer of ethylene and acrylic acid. The collapsible administration container of the present invention can be cored. 35 are constructed from the laminated substrate of the present invention by conventional and known devices. Examples of such an installation and method can be found in U.S. Patent 3,832,964.

Another object of the present invention is to provide a method for the production of laminated tubes, whereby a barrier layer and an ethylene-propylene-copolymer laminated thereto are formed into a tubular body. the laminated tube body is then placed on a molding element next to a barrier element also thereon.

Other objects and advantages of the invention will become more apparent as the description progresses.

In the drawings, in which the same numbers are always used to indicate the same parts: Fig. 1 is a cross section of a fragmentary part. of a laminated substrate of the present invention; FIG. 2 is a side view of a collapsible administration container embodying the novel views of this invention, with parts of the body walls broken away to more fully illustrate the laminated structure.

The thermoplastic of the present invention 20 is ethylene-propylene copolymer.

Reference is now first made to Fig. 1 of the drawings, in which a substrate is shown in cross-section, revealing the components of the sandwich, which will assemble the laminated configuration.

It will be understood that the bottom layer 11 consists of an ethylene-propylene copolymer. The superimposed second layer 12 is an adhesive layer which connects the ethylene-propylene copolymer layer 11 to the third layer 13, which is a metal foil, such as aluminum foil. The fourth layer 14 is again an adhesive which adheres the other surface of the metal foil layer 13 to a paper layer 15. The top layer 16 consists of ethylene-propylene copolymer.

The ethylene-propylene copolymer is particularly suitable because it has very weak flavor absorption characteristics, as shown in the following tables, where ethylene-propylene copolymer is compared with polyethylene, the thicknesses of the layers or coating the same are: 1:: ', η' ·. -i v -5-

T A 3 Ξ L A

Absorption of uncut flavoring oil by polymer Γ (2-week contact) I Polymer weight gain (%)

Aluminum 0 ethylene-propylene copolymer

RigideX 40 (British Petroleum) 4.8 low density polyethylene

Tenite 154 (Eastman) 5.5 low density polyethylene

Lupolen 1804 (BASF) 5.6 ± 0.14 high density polyethylene LR (USD 5.9 ionomer

Surlyn 1707 (Dupont) 15.7 ionomer

Surlyn 1605 (Dupont) 19.0 ionomer

Surlyn 1706 (Dupont) 24.03 _TABLE B_

Relative flavor absorption by polymers after contact with dentifrice for three months. *

Polymer absorbed flavoring

Ethylene-propylene copolymer

Rigidex 40 (British Petroleum) 59 High Density Polyethylene LR (USI) 84 Low Density Polyethylene NA (USD 100 ± 13 ionomer

Surlyn 1706 893

Surlyn 1707 1557 ionomer

Surlyn 1605 1672 ". - - Λ f> * '·. * 1 w * -6-

* at 32 ', 2 ° C

** relative to low density polyethylene, the absorption of which was arbitrarily set at 100; the lower the number, the less flavor was absorbed.

It has been taken into account that, in the context of the invention, the adhesives may be a copolymer of ethylene and acrylic acid or methacrylic acid, or sodium or zinc salts thereof in a diluent system.

The metal foil is preferably aluminum foil.

It is desirable that the paper layer consists of kraft paper.

The thickness range of each of the layers is as follows: ethylene-propylene copolymer layer 11: 0.0127 mm to 0.0762 mm, preferably 0.0254 mm. Bonding layer 12: sufficient to ensure bonding. Metal foil layer 13: 0.0127 mm to 0.0508 mm, preferably 0.0254 mm. Bonding layer 14: sufficient to ensure bonding. Paper layer 15: 0.0381 mm to 0.0635 mm, preferably 0.0508 mm. Ethylene-propylene-copolymer layer 16: 0.0889 mm to 0.1270 mm, preferably 0.1016 mm.

The top ethylene-propylene copolymer layer 16 is adhered to the paper layer 15 by applying sufficient heat and pressure to the substrate. In case application of heat and pressure is not suitable, a suitable adhesive should be used.

Pig. 2 is an example of the laminated structure of a collapsible container, wherein the layers are shown as in FIG. 1 with layer 11 as the inner, and the other layers are of the same materials and are in the same order as shown therein.

It is believed that it is clear from the foregoing that the Applicant has provided a collapsible container structure which substantially reduces the hitherto unresolved problems. The laminated substrate and the laminated shoulder pad 20 substantially eliminate product permeation and oxygen absorption.

The outer layer, consisting of an ethylene-propylene copolymer, is a thermoplastic layer, which can melt during a side-sizing step and provides adequate protection to the paper interlayer and the interlayer;

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£ * metal foil interlayer can provide. The zoom technique on a collapsible dentifrice tube of the general type described herein can be derived from U.S. Patent 3,295,725.

However, the outer layer of ethylene-propylene copolymer and paper can be eliminated if the foil barrier has sufficient thickness to resist damage and to flow a thermoplastic material into the wrap-over seam during welding when such a system is used is used.

Furthermore, in a three-layer laminate formed of paper, foil and an ethylene-propylene copolymer in the manner described, the outer layer may be of paper. Since the outer and inner layers are preferably made of the same material, the folded edges of the tube made from the substrate are easily heat-bonded together. A suitable adhesive can be used when heat bonding is not possible. This modification is an additional modification in addition to the aforementioned four-layer laminate, consisting of, from the outside in, ethylene-propylene copolymer, paper, foil, and ethylene-propylene copolymer. It has been taken into account that suitable adhesives will be used between the laminae if necessary.

Ethylene-propylene copolymers can also be used for the yoke, cap, neck, plunger, and in the construction of delivery valves for other dentifrice delivery devices, particularly in connection with the interior portions attached to the dentifrice contained therein have been exposed and, again, of course, compatible adhesives will be used where required.

When the material is cast as a film on the inner surfaces of fiber drums used for storage of flavored dentifrice, that material will retard the loss of flavor within the drums, thereby extending the storage time.

Several modifications of the invention have been described herein, and these and other changes may of course be accomplished without departing from the new concepts of the present contribution.

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Claims (10)

A substrate of layers of materials comprising: a first layer of an ethylene-propylene copolymer, a second layer of metal foil, a third layer of paper and a fourth layer of an ethylene-propylene copolymer. The substrate according to claim 1, wherein the first layer of the ethylene-propylene copolymer is attached to the metal foil with an adhesive. The substrate of claim 1 or 2, wherein the third layer of paper is attached to the fourth layer of the ethylene-propylene copolymer with an adhesive. The substrate of any one of claims 1 to 3 wherein the first layer of the ethylene-propylene copolymer is attached to the metal foil with an adhesive and wherein the third layer of paper is attached to the fourth layer of the ethylene-propylene copolymer with an adhesive. 15 The substrate according to claim 4, wherein the adhesive is a copolymer of ethylene and acrylic acid. 6. A collapsible paste administration container, consisting of layers of materials, comprising a first inner layer of an ethylene-propylene copolymer, a second layer of metal foil, a third layer of paper, and an outer fourth layer of an ethylene-propylene. copolymer. The container according to claim 6, wherein the first layer of the ethylene-propylene copolymer is attached to the metal foil with an adhesive. The container according to claim 6 or 7, wherein the third layer of paper is attached to the fourth layer of the ethylene-propylene copolymer with an adhesive. The container according to any one of claims 6-8, wherein the first drawer; of the ethylene-propylene copolymer is attached to the metal foil; : 30 with an adhesive and in which the third layer of paper to the fourth layer var. the ethylene-propylene copolymer is attached with an adhesive. The container according to claim 9, wherein the adhesive is a copolymer of ethylene and acrylic acid. r ·· - · ’· ·· '! V /