GB2184395A

GB2184395A - Collapsible dispensing container

Info

Publication number: GB2184395A
Application number: GB08701596A
Authority: GB
Inventors: Edward A Tavss; Samuel C Temin
Original assignee: Colgate Palmolive Co
Current assignee: Colgate Palmolive Co
Priority date: 1983-12-30
Filing date: 1987-01-26
Publication date: 1987-06-24
Also published as: SE463868B; DE3445815A1; NO845266L; DK618184D0; NO163763B; ZW22284A1; FR2557503B1; IE843351L; JPS60220748A; SE8406432L; AT386563B; GR82563B; GB2151986A; BR8406756A; IT8449360A0; GB2184395B; IN162574B; ZA849957B; BE901405A; DK618184A

Abstract

A collapsible dentifrice tube has an inner layer of a polyester. Preferably the tube consists of a substrate of inner and outer layers (11, 16) of polyethylene terephthalate or another polyester, having sandwiched therebetween a metal foil layer (13) and a paper layer (15). <IMAGE>

Description

1 GB2184395A 1

SPECIFICATION

Laminated substrate and collapsible dispensing container made therefrom k The present invention relates broadly to the container art, and is more particularly concerned 5 with a collapsible dispensing container of laminated wall construction in the body portion thereof, 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 long been known in the packaging field. Extruded metal tubes are inherently brittle and repeated use not infrequently results in wall cracks so that product is extruded from a location other than the essentially rigid dispensing orifice. Of the prior art metal tubes, aluminium tubes, while 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 re quired to prevent attack and corrosion of the metal by alkaline or acid contents and contamina tion 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 step which necessarily increases the cost of the final articles.

Tubes formed of polyethylene and other plastic materials have enjoyed wide commercial success in the packaging of many products; however, certan other products after a time have 20 been noted to deteriorate when contained therein. Plastic as exemplified by polyethylene are permeable to a degree when employed 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 absorbs oxygen over a period of time and ultimately may decompose the product, which 25 has actually been found to be the case with fluoride-containing toothpastes.

It has accordingly been proposed to provide a relatively thin metallic foil barrier between the product and the polyethylene tube body to prevent the mentioned loss of essential oils and the absorption of oxygen. The metallic barrier has been suggested as an inteflayer between facing sheets of polyethylene, and that a laminate be formed by heat with or without suitable adhe- 30 sives. 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 an olefin and a polar group containing monomer which is co-polymerizable therewith, there remains the possibility of product deterioration albeit to a much lesser extent.

A disadvantage in a polyolefine surface resides in the inability of the surface to readily receive printing or decorative material. In addition, polyolefin has a memory effect; that is, it does not remain compressed when squeezed, a particular disadvantage for dentifrice tubes. To counter such lack of compressibility the metal layer must be relatively thick so that its compressibility is imposed on the plastic.

An object of the present invention lies in the provision of a tubular container having a plurality of adherent layers in the body portion thereof, one of said layers providing a barrier to product migration and oxygen absorption such as a metallic foil and another of said layers being of a material which avoids the above disadvantages.

According to one aspect of the invention, the other layer is a polyester, and preferably a polyalkylene material, for example polyethylene terephthalate or polybutylene. terephtha late, or a copolymer with a minor amount of another dicarboxylic acid with variable density, melting point, and crystallinity. The said other layer will generally be the innermost layer, but it may also comprise the outermost layer, with different additional laminae sandwiched between the inner and outer layers.

Such additional layers may comprise 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 apparatus. Examples of such apparatus and method can be discerned from U.S. patent No.3,832,964, which is incorporated herein by reference.

The invention includes the multi-layer substrate for forming the container.

A further aspect of the instant invention is a method of producing laminated tubes in which a tubular body is formed of a barrier layer and a polyester thereof laminated thereto; the laminated tube body is then located on a forming member in adjacency to a barrier member also positioned thereon.

The invention may be carried into practice in various ways and one embodiment will be described by way of example with reference to the accompanying drawings, in which:

Figure 1 is a cross-sectional view of a fragmentary portion of a laminated substrate of the present invention; and Figure 2 is a side elevational view of a collapsible dispensing container embodying the novel 65 2 GB2184395A 2 concepts of this invention, with portions of the body walls being broken away to more fully illustrate the laminated structure.

Referring now first to Fig. 1 of the drawings, a substrate 10 is shown in cross-section whereby to reveal the components of the sandwich that goes to make up the laminated 5 configuration.

The bottommost layer 11 is a polyester. The second layer 12 thereabove is an adhesive layer which joins the polyester layer 11 with a third layer 13 which is a metal foil such as aluminium foil. The fourth layer 14 is another adhesive that secures the other surface of the metal foil layer 13 to a paper layer 15. The topmost layer 16 is a polyester.

The thermoplastic polyester of the present invention encompass such polyalkylene terephtha- 10 fates as polyethylene terephthalate and polybutylene terephthalate.

Some polyester resins suitable for this kind of container are disclosed in U.S. Patent Specifications Nos. 3,152,515 and 4,197,326, and the disclosures are incorporated into this specification by reference.

It is contemplated that within the purview of the invention the adhesives may be a copolymer 15 of ethylene and acrylic acid or methacrylic acid, or sodium or zinc salts thereof in a diluent system.

The metal foil may be preferably aluminium foil.

The paper layer is desirably a kraft paper.

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

Polyester layer 11-0.5 mils to 3.0 mils, preferably 1.0 mils; Adhesive layer 12-sufficient to ensure adherence; Metal foil layer 13-0.5 mils to 2.0 mils, preferably 1.0 mils; Adhesive layer 14-sufficent to ensure adherence; Paper layer 15-1.5 mils to 2.5 mils, preferably preferably 2.0 mils; Polyester layer 16-3.5 mils to 5.0 mils, preferably 4.0 mils.

The topmost acetal polyester 16 adheres to the paper layer 15 by means of the application of sufficient heat and pressure to the substrate. If the application of heat and pressure is not appropriate a suitable adhesive is to be employed.

Fig. 2 is an example of the laminated structure of a collapsible container with the layers being 30 demonstrated as in Fig. 1 with layer 11 being inner most and the other layers being of the same materials and in the same order as shown.

It is believed manifest from the foregoing that a collapsible container structure has been provided which substantially reduces the problems heretofore unsolved by the prior art. The laminated substrate and laminated shoulder piece 20 substantially eliminate product permeation 35 and oxygen absorption, and this highly desirable result is achieved by the use of low cost materials which preferably are combined into laminated form in the manner indicated in Fig. 2.

The polyester of the outer layers is a thermoplastic capable of fusion during a side seaming step and giving adequate protection to the paper and metallic foil interlayers. The art of seaming of a collapsible dentifrice tube of the general type herein disclosed can be seen in U.S. Patent 40 No. 3,295,725, incorporated herein by reference.

However, the outer layer of polyester and paper may be eliminated if the foil barrier is of sufficient thickness to resist damage; if the tube is made with an overlapping side seam, a thermoplastic material may be caused to flow into the overlapping side seam during the sealing operation.

Further, the outer layer may be paper in a three-ply laminate form of paper, foil and polyalky lene terephthalate or other polyester as described. As the outermost and innermost layers are preferably the same, the folded over overlapped edges of tubes produced from the substrate are conveniently formed by heat bonding. A suitable adhesive can be used when heat bonding is not possible. This modification is in addition to the aforementioned four-ply laminates comprised of-from outside to in-polyester, paper, foil, and polyester; or polyester, foil, paper, and polyester. It is contemplated that suitable adhesives will be employed between the laminae whenever necessary. Similar laminated structures can be employed for such components as shoulder pieces, caps necks, rods, pistons and dispensing valves, particularly where an interior surface is exposed to the contained dentifrice, and, again, where required, compatible adhesives would naturally be employed.

When cast as a film on the interior surface of a fibre drum used for the storage of flavoured dentifrice, the'material will retard flavour loss into the drum, thereby extending storage life.

The polyethylene terephthalate (PET) is particularly useful because it has very low flavour absorption characteristics as can be seen from the following tables where PET is compared with 60 polyethelene where the thicknesses of layers or coating are the same:

-.4, 3 GB2184395A 3 v 1 t TABLE 1 ABSORPTION OF FLAVOUR FROM A DENTIFRICE PASTE (Aging Condition: 1 week at Room Temperature) Flavour Absorbed 0.1 0.0 0.0 0.5 2.4 PET PET aluminized (1112-2 ohm) PET Aluminized (2-3 ohm) Nylon 6,6 10 Polyethylene TABLE 11 ABSORPTION OF FLAVOUR FROM A DENTIFRICE GEL 15 (Aging Condition: 2 weeks at Room Temperature) Flavour Absorbed 0.0 0.0 0.0 0.2 1.0 PET PET Aluminized (11/2-2 ohm) PET Aluminized (2-3 ohm) 20 Nylon 6,6 Polyethylene

Claims

1. A substrate of layers of materials comprising a first layer of a polyester, a second layer of metal foil, a third layer of paper and a fourth layer of a polyester.

2. The substrate of Claim 1, wherein the polyester is a copolymer of a polyalkylene terephthalate.

3. The substrate of Claim 2, wherein the polyester is polyethylene terephthalate.

4. The substrate of Claim 2, wherein the polyester is polybutylene terephthalate.

5. The substrate of any preceding claim, wherein the first layer of the polyester is secured to 30 the metal foil with an adhesive.

6. The substrate of any of the preceding claims, wherein the third layer of paper is secured to the fourth layer of the polyester with an adhesive.

7. The substrate of any preceding claim, wherein the first layer of the polyester is secured to the metal foil with an adhesive and wherein the third layer of paper is secured to the fourth 35 layer of the polyester with an adhesive.

8. The substrate of any of Claims 5-7, wherein the adhesive is a copolymer of ethylene and acrylic acid.

9. A collapsible paste dispensing container of multi-layer material, of which the innermost layer is a polyester.

10. A container as claimed in Claim 9, in which the outermost layer is a polyester.

11. A container as claimed in Claim 9 or Claim 10, including an intermediate layer of paper.

12. A container as claimed in any of Claims 9 to 11, including an intermediate layer of metal foil.

13. A collapsible paste dispensing container of layers of materials comprising a first inner- 45 most layer of a polyester, a second layer of metal foil, a third layer of paper and an outermost fourth layer of a polyester.

14. The container of any of Claims 9 to 13, wherein the polyester is a copolymer of a polyalkylene terephthalate.

15. The container of any of Claims 9 to 14, wherein the polyester is polyethylene terephtha- 50 late.

16. The container of any of Claims 9 to 14, wherein the polyester is polybutylene terephtha late.

17. The container of any of Claims 12 to 16, wherein a layer of the polyester is secured to the metal foil with an adhesive.

18. The container of any of Claims 11 to 17, wherein the layer of paper is secured to a layer of the polyester with an adhesive.

19. The container of Claim 17 or Claim 18, wherein the adhesive is a copolymer of ethylene and acrylic acid.

20. A substrate of layers of materials substantially as herein specifically described with 60 reference to Fig. 1 of the accompanying drawings.

21. A paste dispensing container constructed and arranged substantially as herein specifically described with reference to Fig. 2 of the accompanying drawings.

4 GB2184395A 4 Printed for Her Majesty's Statiogery Office by Burgess & Son (Abingdon) Ltd, Dd 8991685, 1987. Published at The Patent Office, 25 Southampton Buildings, London, WC2A 1 AY, from which copies may be obtained.

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