CA1222687A

CA1222687A - Laminated polyester containing substrate and collapsible dispensing container made therefrom

Info

Publication number: CA1222687A
Application number: CA000471142A
Authority: CA
Inventors: Edward A. Tavss; Samuel C. Temin
Original assignee: Colgate Palmolive Co
Current assignee: Colgate Palmolive Co
Priority date: 1983-12-30
Filing date: 1984-12-28
Publication date: 1987-06-09
Also published as: SE463868B; DE3445815A1; GB2184395A; NO845266L; DK618184D0; NO163763B; ZW22284A1; FR2557503B1; IE843351L; JPS60220748A; SE8406432L; AT386563B; GR82563B; GB2151986A; BR8406756A; IT8449360A0; GB2184395B; IN162574B; ZA849957B; BE901405A

Abstract

ABSTRACT OF THE DISCLOSURE

There is disclosed a substrate of layers of materials comprising polyester layers having sandwiched therein between a metal foil layer and a paper layer all suitably adhered to one another, the substrate being employed in fabricating a dent-ifrice tube having substantially no product permeation and ab-sorption, or oxygen absorption.

Description

LAMINATED POLYESTER CONTAINING SUBSTRATE AND
COLLAPSIBLE DISPENSING CONTAIMER MADE THEREFROM

The present invention relates broadly to the container art, and is more particularly concerned with a collapsible dis-pensing 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 mater-ials have long been known in the packaging field. Extruded metal tubes are inherently brittle and repeated use not in-frequently results in wall cracks so that product is exuded from a location other than the essentially rigid dispensing orifice. Of the prior art metal tubes, aluminum tubes, while probably being the least brittle, are somewhat limited in their applications since up to the present time it has not been pos-sible to apply to the interior surfaces thereof a completely satisfactory coating, when required to prevent attack and cor-rosion of the metal by alkaline or acid contents and contamin-ation of the contents by the reaction products. Nokwithstandingthe relatively brittle nature of a metal tube, the mentioned internal coating operation requires an additional processing step which necessarily increases the cost of the flnal article.
I'ubes formed of polyethylene and other plastic mater-ials have enjoyed wide commercial success in the packaging of many products;however, certain other products after a time have been noted to deteriorate when contained therein. Plastics as exemplified by polyethylene are permeable to a degree when em-ployed in the wall thicknesses used in tubular containers, and the essential oils embodied in most dentifrices for flavoring 26~37 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 ult-imately may decompose the product, which has actually been found to be the case with fluoride-containing toothpastes.

-la-~2Z~:6~7 It has accordingly been proposed to provide a rela-tively thin metallic foil barrier between the product and the polyethylene tube body to prevent the mentioned loss if essential oils and the absorption of oxygen. The metallic barrier has been suggested as an interlayer between acing sheets of polye~hylene, and that a laminate 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 an olefin and a polar group containing monomer which is co-polymerizable therewith, there remains the possibili~y of product deteterioration albeit to a much lesser extent.
A disadvantage in a polyolefin 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.
20 To counter such lack of compressibility the metal layer must be relatively thick so that its compressibility is imposed on the plastic.
SUMM~RY OF THE INVENTION
It is, therefore, an important aim of the present invention to provide a collapsible dispensing container of laminated wall construction in the body portion.
Another object of this 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 a polyal~ylene material selected from the group consisting of polyethylene terephthalate and polybutylene terephthalate or copolymer with a minor amount of other dicarboxylic acid of a varying in density, melting point and crystallinity.
The latter layer being innermost and preferably outermost with different aclditional laminae sandwiched therein between.
Such additional layers comprise paper and suitable adhesive and bonding a~er.ts such as copolymer of ethylene and acrylic acid. The collapsible clispensing container of the present invention may be constructed from the laminated sub-strate of the present invention by conventional and known appar-atuses.
According to the present invention, there is provided 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.
There is also provided a collapsible paste dispensing container of layers of materials comprising a first innermost layer of a polyester, a second layer of metal foil, a third layer of paper and an outermost fourth layer of a polyester.
In another aspect, the invention provides a method of producing laminated tubes in which a tubular body is formed of a barrier layer and a polyester laminated thereto; the laminated tube body is then located on a forming member in adjacency to a barrier member also positioned thereon.
In the drawings wherein like numerals are employed to designate like parts throughout the same: Figure l is a cross-sectional view of a fragmentary portion of a laminated substrateof the present invention. Figure 2 is a side elevational view of a collapsible dispensing container embcdying the novel con-cepts oE this invention, with portions of the body walls being broken away to more fully illustrate the laminated structure.
Referring now first to Figure 1 of the drawings, a sub-strate lO is shown in cross-section whereby to reveal the compon-ents of the sandwich that goes to make up the laminated config-uration.
It will be seen that the bottommost layer ll is a poly-ester. The second layer 12 thereabove is an adheslve layer Z22~7 which joins the polyester layer 11 with a third layer 13 whichis a metal foil such as aluminum foil. The fourth layer 1~ is another adhesive that adhesively secures the other surface o~
the metal foil layer 13 to a paper layer 15. The topmost layer 16 is a polyester.
The thermoplastic polyester of the present invention encompasses polyalkylene terephthalate such as polyethylene terephthalate and polybutylene terephthalate.

-3a-12226~3'7 The applicable polyester resins are disclosed with regard to container usage in U.S. Patents 3,152,515 and 4,197,326.
These patents disclose, for instance, as a polyester polyethylene terephthalate.
It is contemplated that within the purview 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 may be preferably aluminum Eoil.
The paper layer is desirably a kraft paper.
The thickness range of each of the layers is as follows:
Polyethylene terephthalate layer 11 0.5 mils to 3.0 mils, preferably 1.0 mils.
Adhesive layer 12 - sufficient to assure adherence Metal foil layer 13 - 0.5 mils to2.0 mils, preferably 1.0 mils Adhesive layer 14 - sufficient to assure adherence Paper layer 15 - 1.5 mils to 2.5 mils, preferably 2.0 mils.
Polyethylene terephthalate layer 16 - 3.5 mils to 5.0 mils, preferably 4.0 mils.
The topmost Polyethylene terephthalate layer 16 adheres to the paper layer 15 by means of the application of sufficient heat and pressure to the suhstrate. In the event the ; application of heat and pressure is not appropriate a suitable adhesive is to be employed.
Figure 2 is an example of the laminated structure of a collapsible container with the layers being demonstrated as in Figure 1 with layer 11 being inner most and the other layer being of the same materials and in the same order as shown.
It is believed manifest from the foregoing that 122~t~8~

applicant has provided a collapsible container structure which substantially reduces the problems heretofore unsolved by the prior art. The laminated substrate and laminated shoulder piece 20 completely eliminates product permeation 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 Figure 2.
The outer layer of an polyethylene terephthalate thereof is a thermoplastic capable of fusion during a side seaming 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. 3,295,725.
However, the outer layer of polyalkylene terephthalate 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 during the sealing thereof when such a system is employed~
Further, the outer layer may be paper in a three-ply laminate Eorm of paper, foil and a polyalkylene terephthalate as described. As the 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 20 possible. This modification is in addition to the aforementioned four-ply laminates comprised of from outside to in, polyalkylene terephthalate, paper, foil and polyalkylene terephthalate; or polyalkylene terephthalate, foil, paper and polyethylene terephthalate. It is contemplated 25 that suitable adhesives will be employed between the laminae whenever necessary. Like structures can be employed for the shoulder piece, cap, neck, rod, piston and in the construction of dispensing valves for such containers, particularly in con-1~

~Z6~7 -5a-junction with the interior portions 30 exposed to the contained dentifrice, and, again, where required, compatible adhesives would naturally be employed.
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 instant contribution. Additionally when cast as a film on the interior surfaces of fiber drums used for the storage of flavored denti-frice, the material will retard flavor loss into the drums, thereby extending storage life.
The polyethylene terephthalate (PET) is particularly 12ZZ~7 useful because it has very low flavor absorption characteristics as can be seen ~rom the following tables where PET is compared with polyethylene where the thicknesses of layers or coating are the same:
TABLE I
., ABSORPTION OF FLAVOR FROM A DENTIFRICE PASTE
(Aging Condition: 1 Week at Room Temperature) Flavor Absorbed (%) PET 0.1 PET Alum~nized (1~ - 2 ohm) 0.O
PET Aluminized (2 - 3 ohm) 0.O
Nylon 6,6 0 5 Polyethylene 2.4 TABLE II
ABSORPTION OF FLAVOR FROM A DENTIFRICE GEL
~Aging Condition: 2 Weeks at Room Temperature~ .

Flavor Absorbed (~) PET
PET Aluminized (1~ - 2 ohm) o.o PET Aluminized (2 - 3 ohm) 0.0 Nylon 6,6 0.2 Polyethylene 1.0

Claims

What is claimed is:

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

2. The substrate of claim 1 wherein the polyester is a copolymer of an polyalkylene terephthalate.

3. The substrate of claim 2 wherein the polyalkylene terephthalate is polyethylene terephthalate.

4. The substrate of claim 3 wherein the first layer of the polyethylene terephthalate is secured to the metal foil with an adhesive.

5. The substrate of claim 4 wherein the third layer of paper is secured to the fourth layer of the polyethylene terephthalate with an adhesive.

6. The substrate of claim 5 wherein the first layer of the polyethylene terephthalate is secured to the metal foil with an adhesive and wherein the third layer of paper is secured to the fourth layer of the polyethylene terephthalate with an adhesive.

7. The substrate of claim 6 wherein the adhesive is a copolymer of ethylene and acrylic acid.

8. A collapsible paste dispensing container of layers of materials comprising a first innermost layer of a polyester, a second layer of metal foil, a third layer of paper and an outermost fourth layer of a polyester.

9. The container of claim 8 wherein the polyester is a polyalkylene terephthalate.

10. The container of claim 9 wherein the polyester is a polyethylene terephthalate.

11. The container of claim 10 wherein the first layer of the polyester is secured to the metal foil with an adhesive.

12. The container of claim 10 wherein the third layer of paper is secured to the fourth layer of the polyester with an adhesive.

13. The container of claim 10 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 layer of the polyester with an adhesive.

14. The substrate of claim 13 wherein the adhesive is a copolymer of ethylene and acrylic acid.