GB2206532A - Packaging articles incorporating fluorinated polyethylene - Google Patents

Description

22206532 J 12604 1.

LAMINATING SUBSTRATE AND ARTICLE THEREFROM INCORPORATING LAMINATED POLYETHYLENE The present invention relates broadly to the container art, and is more particularly concerned with a collapsible dispensing container of laminated wall construction in the body portion thereof, 5. whereby product permeation and absorption, and oxygen absorption are substantially prevented in all regions of the container structure susceptible thereto.

Collapsible tubes formed of metallic and plastic materials have long been known in the packaging 10. field. Extruded metal tubes are inherently brittle and repeated use not infrequently results in wall cracks so that the product is exuded from a location other than the essentially rigid dispensing orifice. Of the prior art metal tubes, aluminium tubes, while

15. probably being the least brittle, are somewhat limited in their applications since up to the present time it has not been possible to apply to the interior surfaces thereof a completely satisfactory coating, when required to prevent attack and 20. corrosion of the metal by alkaline or acid contents and contamination of the contents by the reaction products. Notwithstanding the relatively brittle nature of a metal tube, the mentioned ' internal coating operation requires an additional processing 25. step which necessarily increases the cost of the final article.

Tubes formed of polyethylene and other plastic materials have enjoyed wide commercial success in the 30.

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packaging of many piodu cts; however, certain other products after a time have been noted to deteriorate when contained therdin. Plastics as exemplified by polyethylene are permeable to a degree when employed 5. in the wall thicknesses used in tubular containers, and the essential oils embodied in most dentifrices for flavouring purposes are reduced in volume during storage of the container, rendering the dentifrice less palatable. Also, the plastic container wall 10. absorbs oxygen over a period of time and ultimately may decompose the product, which has actually been found to be the case with fluoride-containing toothpastes. A further disadvantage of a plastic tube resides in the inability of the surface to readily receive printing or decorative material.

addition, plastic tubes, as exemplified by polyethylene, have a memory effect; that is, they do not remain compressed when squeezed, a particular disadvantage for dentifrice tubes.

20. To counter the above problems, it has accordingly been proposed to provide a metallic foil barrier between the product and the polyethylene tube body.

This would counter the compressibility problem in that the metal layer would impose its compressibility 25. upon the plastic. In addition, the metallic foil barrier between the product and the polyethylene tube body would prevent the mentioned lossof essential oils and the absorption of oxygen. The metallic barrier has been suggested as an interlayer between 30. facing sheets of polyethylene, and that a laminate X 1 j12604 3.

be formed by heat with or without suitable adhesives. However, while a structure of this general character is effective to prevent some product permeation and oxygen absorption through the tube body, and particularly when the inner thermoplastic layer is a copolymer of ethylene olefin and a polar group containing monomer which is co-polymerisable therewith, there remains the p ossibility of product deterioration albeit to a much lesser extent.

10. Attention is directed to the following prior art:

Brandt (U.S. Patent No. 3,295,725) developed a tube which combines advantages of an aluminium tube with advantages of a plastic tube. This is a laminated collapsible dispensing container containing 15. both a metallic barrier and a polyethylene inner wall. The thermoplastic layer is broadly described as polyolefin and copolymer of an olefin and a polar group containing monomer which is copolymerisable therewith. This laminate overcomes the above 20. described limitations, except for absorption of the essential oils from the dentifrices.

Marchak (Canadian Patent No. 728,525) discloses a laminated tube containing an inner layer of polyethylene. He recognised the problem of 25. absorption of flavour oil by the thermoplastic wall, and suggested the use of nylon to overcome this.

Other inventors investigated surface treated polymers in their articles of manufacture. D'Angelo (U.S. Patent No. 4,142,032) in iis studies with films 30. and containers noted that barrier properties are improved by surface treatment with both fluorine and I X 1 J 12604 bromine. However, he did not make a tube; his article had no aluminium; and he did not recognise the flavour barrier properties of this polymer.

Boultinghouse (U.S. Patent No. 4,296,151), 5. Gilmour (4,110,518), Dixon (U.S. Patent No.

4,020,223), Scotland (U.S. Patent No. 3,647,613), and Anand (U.S. Patent No. 4,404,256) also had articles of manufacture involving fluorine surface treated polymers. Boultinghouse demonstrated that the 10. treatment made surfaces receptive to adhesives, coating, paints, inks, decorations, and the like; Gilmour showed that the surface behaves as an electrical insulator; Dixon's treatment imparted oil stain release characteristics; Scotland's treatment 15. provided solvent resistance. None of these articles, however, were tubes; none contained a layer of aluminium; and none of the inventors noted the flavour resistance of these articles.

The present invention aims to provide a 20. collapsible dispensiAg container of laminated wall construction in the body portion.

The present invention also aims to provide a tubular container having a plurality of adherent layers in the body portion thereof, one of said 25. layers providing a barrier to product migration and oxygen absorption such as a metallic foil and another of said layers being ethylene vinyl alcohol copolymer or mixture thereof varying in density and crystallinity The fluorinated polyethylene being innermost 30. and preferably another such layer also being disposed k J 12604 5.

as the outside layer with different additional laminae sandwiched therein between.

Such additional layers may compris.e paper and suitable adhesive and bonding agents such as copolymer of ethylene and acrylic acid.

The collapsible dispensing container of the present invention may be constructed from the laminated substrate of the present invention by conventional and known apparatuses. Examples of 10. suitable equipment and a suitable method are claimed in U.S. Patent No. 3,832,964, which is incorporated herein by reference.

The procedure described in U.S. Patent No. 3,832,964 involves wrapping a sheet of flexible 15. material (in the present case this will be the material of the present invention.) about a mandrel and fastening overlapping side edges together to provide a tubular body having a longitudinal seam Cwhich can be done readily with the material of the 20. present invention because the materials of the inner and outer faces being the same can readily be bonded to each other) and then inserting and clamping one end of the formed body shell between an outer head structure element e.g. affording a neck and shoulders with an outer thread on the neck and an inner head structure element e.g. affording an inner neck and shoulders.

These components may conveniently be formed of or coated on their sheet contacting faces with the 30. polymer of the outer layer of the laminate of the present invention.

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A further object of the present invention is to provide a method of producing laminated tubes in whch a tubular body is formed of a barrier layer and a fluorinated polyethylene laminated thereto; the laminated tube body is then located on a forming member juxtaposed to-a barrier member also positioned thereon.

The invention may be put into practice in various ways and a number of specific embodiments lo., will be described to illustrate the invention with reference to the accompanying examples and drawings, in which:Figure 1 is a cross-sectional view of a fragmentary portion of a laminated substrate of the 15. present invention; and Figure 2 is a side elevational view of a collapsible dispensing container embodying the novel concepts of the present invention, with portions of the body walls being broken away to more fully 20. illustrate the laminated structure.

In the drawings like numerals are employed to designate like parts throughout the drawings.

Referring now first to Figure 1 of the drawings, a substrate 10 is shown in cross-section to reveal the components of the sandwich that go to make up the laminated configuration.

The bottommost layer 11 is a fluorinated polyethylene. The second layer 12 thereabove is an adhesive layer which joins the fluorinated 30. polyethylene layer 11 to a third layer 13 which is a X j12604 metal toil such as aluminium foil. The fourth layer 14 is another adhesive that adhesively secures the other surface of the metal foil layer 13 to a paper layer 15. The topmost layer 16 is fluorinated polyethylene.

The fluorinated polyethylene is particularly useful because it has very low flavour absorption characteristics as can be seen from the following tables where fluorinated polyethylenes are compared 10. with polyethylene where the thicknesses of the layers of coating are the same.

EXAMPLE 1

Samples of polymer were tested by a single-side contact procedure (gravimetric-flavoured dentifrice) 15. using a conventional dental cream containing 0.84% by weight of a mint-peppermint oil blend. Three 2 inch cms) diameter disks of the polymer to be tested are punched out and weighed. Three 2 oz ( g) glass ointment jars are filled to within 1/16 inch mms) 20. of the top. Each disk is placed within an aluminium cap and the cap placed on the jIar and the jar is sealed. The jars are aged for 3 months at the temperatures indicated in Table 1 below. Each disk is removed, rinsed in water, dried and weighed to determine uptake of flavour oil. The amount of flavour absorbed by each polymer after that time at that temperature relative to that absorbed by the low density polyethylene at 72F (32C) is given in Table 1.

30. It will be appreciated that the lower the number the less flavour is absorbed.

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TABLE 1

Relative Flavour Absorption into Polymers from Flavoured Dentifrice 720F 90OF 120F 5. ( OC) ( OC) ( OC) Aluminium 0.4 0 0.4 Fluorine surface-treated 22 37 90 high density polyethylene HD-3 (Air Products) 10. High density polyethylene 98 94 100 HD-O (Air Products) Low density polyethylene 100 94 ill LD-O (Air Products) 15.

EXAMPLE 2

Samples of polymer were tested by a single-side contact procedure (gravimetric-neat flavour oil). A 3/4 inch ( cms) diameter disk of the polymer to be tested is punched out and weighed. A 9 ml vial is 20. filled with neat flavour oil. The disk of polymer is sealed over the top of the vial and the vial is inverted. The vial is aged for 2 weeks at 72'F 'C). The vial is inverted. The disk is removed, rinsed with water, dried and weighed to determine 25. flavour oil uptake. The increase in weight (absorption) is given as a percentage of the original weight of the sample in Table 2 below.

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TABLE 2

Polymer Absorption of Neat Flavour Oil Aluminium 5. Fluorine surface-treated high density polyethylene HD-3 (Air Products) High density polyethylene HD-O (Air Products) Low density polyethylene 10. LD-O (Air Products) Low density polyethylene NA (USI) Ionomer Surlyn 1707 (DuPont) 15. Ionomer Surlyn 1605 (DuPont) Ionomer Surlyn 1706 (DuPont) 20.

Absorption (%) 0 3.3 4.8 7.9 10.0 15.7 19.0 24.3 EXAMPLE 3

Samples of polymer were tested by a total immersion procedure (gravimetric-irregular pieces). A sample piece of the polymer to be tested is weighed and placed in a glass jar. Sufficient neat flavour 25. oil to totally immerse the sample is introduced into the jar. The sample is aged for two weeks at 72'F ( C). The sample is removed, dried and weighed to determine the uptake of flavour oil.

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TABLE 3 Polymer Absorption of Neat Flavour Oil No. 74 fluorine surface-treated Low density polyethylene(a) No. 76 fluorine surface-treated Low density polyethylene(a) Low density polyethylene(b) Low density polyethylene 10. (control)(a) Ionomer(c) Ionomer(d) Notes on Table 3 (a) Low density polyethylene is Lupolen 1804H (BASF) (b) Tenite 154 (Eastman) (c) Surlyn 8940 (DuPont) (d) Surlyn 8920 (DuPont) n=3 % Flavour Absorbed 2.6 2.6 5.5 5.6+0.14(e) 7.4 12.2 EXAMPLE 4

A drop of conventional dental cream containing 0.84% by weight of a mintpeppermint oil blend was put onto a disk of the polymer to be tested in a 25. closed glass container which was held at 90F (32C) for fifteen minutes. An aliquot of the atmosphere above the sample was then analysed to give the absorption by the plastic. Table 4 below gives the amount of flavour oil lost by the dentifrice relative 30. to that lost by the BASF low density polyethylene, the value for which was arbitrarily set at 100.

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It will be appreciated that the lower the number the less is the flavour lost from the dentifrice. TABLE 4 Loss of Flavour from Flavoured Dentifrice into Polymers 5.

No. 76 fluorine surfacetreated low density polyethylene(a) No. 74 fluorine surface-treated 10. low density polyethylene(a) Ionomer(b) Ionomer(c) Low density polyethylene (control)(a) Low density polyethylene(d) 15.

Notes on Table 4 (a) LDPE is Lupolen 1804M (BhSF) (b) Surlyn 8920 (DuPont) (c) Surlyn 8940 (DuPont) 20. (d) Tenite 154 (Eastman) Flavour Loss 56 64 88 96 100 136 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 aluminium foil.

The paper layer is desirably a kraft paper.

The thickness range of each of the layers is as follows:

Fluor-nated polyethylene layer 11 - 0.5 mils to 3.0 mils (... mm to... mm), preferably 1.0 mils mm).

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Adhesive layer 12 - sufficient to assure adherence.

Metal foil layer 13 - 0.5 mils to 2.0 mils mm to... mm), preferably 1.0 mils 5. Adhesive layer 14 - sufficient to assure adherence.

Paper layer 15 - 1.5 mils to 2.5 mils... mm to mm), preferably 2.0 mils (. .. mm).

Fluorinated polyethylene layer 16 - 3.5 mils to 10. 5.0 mils (... mm to... mm), preferably 4.0 mils mm).

The topmost fluorinated polyethylene layer 16 is adhered to the paper layer 15 by means of the substrate. In the event the application of heat and 15. pressure is not appropriate a suitable adhesive is employed.

Figure 2 is an exampl of the laminated structure of a collapsible container with the layers being demonstrated as in Figure 1 with layer 11 being 20. innermost and the other layers being of the same materials and in the same order as shown.

It is believed manifest from the foregoing that applicant has provided a collapsible container structure which substantially reduces the problems 25. heretofore unsolved by the prior art. The laminated substrate and laminated shoulder piece 20 substantially eliminates product permeation and oxygen absorption.

The outer layer of fluorinated polyethylene is a 30. thermoplastic capable of fusion during a side seaming k 1 c 1 J12604 step and granting adequate protection to the paper and metallic foil interlayer. The art of seaming of a collapsible dentifrice tube of the general type herein disclosed can be seen in U.S. Patent No.

5. 3,295,725, incorporated herein by reference.

However, the outer layer of fluorinated polyethylene and paper may be eliminated if the foil barrier is of sufficient thickness to resist damage, and by flowing a thermoplastic material into the overlap side seam 10. during the sealing thereof when such a system is employed.

Further, the outer layer may be paper in a three-ply laminate formed of paper, foil and fluorinated polyethylene as described. As the 15. outermost and innermost layers are preferably the same, the folded edges of the tube produced from the substrate is conveniently heat bonded. A suitable adhesive can be used when heat bonding is not possible. This modification is in addition to the 20. aforementioned four-ply laminate comprised of from outside to in, fluorinated polyethylene, paper, foil and fluorinated polyethylene.

It is contemplated that suitable adhesives will be employed between the laminae whenever necesssary. Fluorinated polyethylene can be employed for the shoulder piece, cap, neck, piston and in the construction of dispensing valves for other dentifrice dispensers, particularly in conjunction with the ii-cerior portions, exposed to the contained 30. dentifrice, and, again, where required, compatible adhesives would naturally be employed.

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Additionally when cast as a film on the interior surfaces of fibre drums used for the storage of flavoured dentifrice, the material will retard flavour loss into the drums, thereby extending 5. storage life.

Various modifications of the invention-have been disclosed herein, and these and other changes can, of course, be effected without departing from the novel concepts of the present invention.

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Claims (1)

1. A package containing a composition containing one or more flavour oils, the interior surfaces of the package in contact with the said composition being afforded by fluorinated polyethylene 5.

1 tent Office.

IPYrIR 4TP- F=ther coi:)les maybe obtained from The Pa thyriR 4TP- F=trier coPies may be obtained Irom The Patent umce,