LU86232A1 - LAMINATE SUBSTRATE CONTAINING FLUORINATED POLYETHYLENE AND CONTAINER COMPRISING APPLICATION - Google Patents

Description

..

The present invention relates, in general, the container technique and, more particu-ΐ ly, a collapsible dispenser container whose wall is laminated in the body portion of it! 05 itself, whereby penetration and absorption of the product and absorption of oxygen are largely avoided in all regions of the structure of the | i container that are sensitive to it.

! ! Crushable tubes made of metal materials-

! I

I 1 10 plastics and plastics have been known for a long time in the field of packaging. The tubes of extruded metal are intrinsically brittle, and their repeated use frequently leads to cracks in the wall, so | that the product exudes from a place other than the practically rigid dispensing orifice. Among the metal tubes of the prior art, aluminum tubes, although probably the least brittle, have rather limited applications, because so far it has not been possible to apply a completely satisfactory coating to their interior surfaces, when necessary to prevent attack and corrosion of the metal by alkaline or acidic contents and contamination of the content by the products of the reaction. Despite the relatively brittle nature of the metal tubes, the mentioned internal coating operation requires an additional processing step which necessarily increases the cost of the final article.

Tubes made of polyethylene and other plastics have had wide commercial success in the packaging of many products. However, it was noted that some other products deteriorate after some time when they are contained.

Plastics like polyethylene are permeable in; to a certain extent when used in the wall thicknesses used in tubular containers and the essential oils contained in most toothpastes for scenting see their volume reduced during storage of the container , this mistletoe makes the dentition less palatable. Likewise, the wall of the plastic container absorbs oxygen over time, and can ultimately decompose the product; this mistletoe has been found to be the case with fluoride containing pastes. Another disadvantage of plastic tubes lies in the inability of the surface to easily receive a printing or decorative material. In addition, plastic tubes such as polyethylene, have a memory effect, that is to say that they do not remain compressed when crushed, which is a particular disadvantage for toothpaste tubes.

To overcome the above problems, it has therefore been proposed to provide a metal foil as a barrier between the product and the body of the polyethylene tube. This would solve the compressibility problem, in the sense that the metal layer would impose its compressibility on the plastic. In addition, the metallic barrier film between the product and the polyethylene tube body would prevent the loss of essential oils and the absorption of oxygen mentioned above. It has been suggested to use the metal barrier as an intermediate layer between outer layers of polyethylene, and to form a laminate by heating, with or without suitable adhesives. However, although a structure having this general character is effective in preventing a certain penetration of the product and an absorption of oxygen through the body of the tube, and in particular when the internal thermoplastic layer is a copolymer of 1 ' ethylene and a polar group-containing monomer which is copolymerizable with it, there remains the possibility of product deterioration, although to a much lesser extent.

35 Attention is drawn to the following prior art: 3 ι

Brandt (U.S. Patent No. 3,295,725) has developed a tube that combines the above advantages of aluminum tubes with the advantages of tubes! j! plastic. It is a crushable, laminated sand dispenser container containing both a metal barrier and an inner polyethylene wall. The thermoplastic layer is generally described as being a polyolefin and a copolymer of an olefin and a polar group-containing monomer which is copolymerizable with it. This laminate overcomes the limitations described above, except for the absorption of essential oils from toothpaste.

Marchak (Canadian Patent No. 728,525) has also developed a laminate tube containing an inner layer of polyethylene. He recognized the problem of the absorption of odoriferous oil by the thermoplastic wall.

Other inventors have studied surface-treated polymers in their manufactured products. D'Angelo (U.S. Patent No. 4,142,032), in his study of films and containers, noted that barrier properties are improved by surface treatment with fluorine and bromine . However, he did not manufacture a tube; his article did not contain aluminum, and he did not recognize the barrier properties of this polymer for flavorings.

Boultinghouse (U.S. Patent No.A 4.2926,151), Gilmour (US-A-4,110,518), Dixon (U.S. Patent

j 30 No. 4.020.223), Scotland (US patent No. 3,647,613) ii and Anand (brevet patent. UA No. 4,404,256), have also described manufactured products involving i polymers surface treated with fluorine. Boultinghouse! .. „has demonstrated that the treatment makes surfaces receptive. 35 adhesives, coatings, paints, inks, decorations, etc., Gilmour has shown that the surface behaves like an electrical insulator, the Dixon treatment | i. * i / 4 conferred characteristics of ability to remove oil stains; Scotland's treatment provided resistance to solvents. None of these products, however, were a tube; none of them contained a layer of aluminum; and none of the inventors noted the flavor resistance of these articles.

An important object of the present invention is therefore to provide a collapsible dispensing container with a laminated wall in the body part.

Another object of the invention is to provide a tubular container comprising several adherent layers in its body part, one of these layers constituting a barrier with regard to the migration of the product and to the absorption of oxygen, such as a metal foil, and another "of these layers being a fluorinated polyethylene or a mixture based thereon, of variable density and high-density. This latter layer being the most internal and preferably the most external, with various additional layers sandwiched together.

These additional layers include paper and a suitable adhesive, and bonding agents such as a copolymer of ethylene and acrylic acid.

The collapsible dispensing container of the present invention can be made from the laminate substrate of the present invention using conventional and known apparatus. Examples of this apparatus and process are found in U.S. Patent No. 3,832,964, which is incorporated herein by reference.

Another object of the present invention is to provide a method of manufacturing laminate tubes in which a tubular body is formed of a barrier layer and a laminated fluorinated polyethylene thereon; the laminated tube is then placed on a shaping element against a barrier element also placed thereon.

The invention will be better understood on reading; . of the description which will follow, given only at ti-! be an example and made with reference to the accompanying drawings.

In the drawings, in which like reference numerals are used to designate like parts in Figure 1 is a cross-sectional view of a fragment of a laminate substrate of the present invention, * Figure 2 is a side elevation view of one; collapsible dispensing container embodying the new concepts of this invention, parts of the walls of the | body being torn off to illustrate more fully: the layered structure.

The thermoplastic material of the present invention is a fluorinated polyethylene.

In Figure 1 of the drawings, a substrate 10 'is shown in cross section, thus revealing the constituents of the sandwich which forms the layered structure.

: It can be seen that the lower layer 11 is a fluorinated polyethylene. The second layer 12 above; this is an adhesive layer which connects the layer of fluorinated polyethylene 11 to the third layer 13 which is a metal sheet such as an aluminum sheet.

The fourth layer 14 is another adhesive which fixes the other face of the layer of metal foil 13 by adhesion to a layer of paper 15. The upper layer 16 is fluorinated polyethylene.

i 30 Fluorinated polyethylenes are particularly useful because they have very low flavor absorption characteristics, as can be seen from the! following tables, in which polyethylene fluo-! res are compared with polyethylene, the thicknesses of the layers or coating being the same: j r "

F

h

î / J

I 'i; "

TABLE I

RELATIVE ABSORPTION OF FLAVOR BY POLYMERS FROM PERFUMED TOOTHPASTS *

22.2 ° C 32.2 ° C 48.9 ° C

05 Aluminum 0.4 0 0.4

High density polyethylene surface treated with HD-3 fluorine (Air Products) 22 37 90

High density polyethylene 10 HD-0 (Air Products) 98 94 100

Low density polyethylene LD-0 (Air Products) 100 94 111 * All numbers refer to low density polyethylene 15 at 22.2 ° C, arbitrarily set as 100; the lower the number, the less the amount of flavor absorbed.

! TABLE II

20 ABSORPTION BY POLYMERS OF A

UNDILUTED ODORIFERANT OIL

Absorption (%)

Aluminum 0

High density HD-3 polyethylene surface treated with fluorine (Air Products) 3.3

HD-0 high density polyethylene. (Air Products) 4.8

Low density polyethylene LD-0 30 (Air Products) 7.9

Low density polyethylene NA

(USI) 10.0

Ionomer

Surlyn 1707 (DuPont) 15.7 35 Ionomer

Surlyn 1605 (DuPont) 19.0

P

t:>; ? v Ionomer 4

Surlyn 1706 (DuPont) 24.3

TABLE III

05 ABSORPTION BY POLYMERS OF A

UNDILUTED ODORIFYING OIL

% d1 ar & me absorbed N ° 74 Low density polyethylene surface treated with fluorine2,6 N ° 76 Low density polyethylene surface treated with fluorine (a> 2.6

Low density polyethylene ^ 5.5 15 Low density polyethylene (control) 5.6 i '0.14 (e)

Ionomer (c) 7.4, Ionomer (^) 12.2 20 a) low density polyethylene is Lupolen 1804 H (BASF), b) Tenite 154 (Eastman), c) Surlyn 8940 (DuPont), d) Surlyn 8920 (DuPont), 25 e) n = 3.

TABLE IV

LOSS OF AROMA FROM A PERFUMED TOOTHPASTE-IN POLYMERS LOSS OF D1 AROMA3 * 30 'N ° 76 Low density polyethylene surface treated with fluorine56 - No. 74 Low density polyethylene 35 surface treated with fluorine IonomereΦ) 88 ^ / / / j I ,, lonomërevc) 96

Low density polyethylene (control) ^ 100

Low density polyethylene ^ 136 05 J * Compared to the low polyethylene control! BASF density arbitrarily set as 100? I the lower the number, the less the amount of aroma • lost by the toothpaste.

10 a) Low density polyethylene is Lupolen 1804 H (BASF), b) Surlyn 8920 (DuPont), c) Surlyn 8940 (DuPont), 15 d) Tenite 154 (Eastman).

It is envisaged that in the context of the invention; - tion, the adhesives can be a copolymer of ethylene and acrylic acid or methacrylic acid, '-. Or the sodium or zinc salts thereof in a diluent system.

The metal sheet may preferably be; aluminum foil.

The layer of paper is advantageously a pa-, 25 pier.kraft.

| The thickness range of each of the layers is advantageously as follows: fluorinated polyethylene layer 11: 12.7 microns to 76.2 microns (0.5 to 3.0 thousandths of an inch), preferably 30 to 24 , 4 microns (1.0 thousandths of an inch), adhesive layer 12: sufficient to ensure adhesion,, »metal foil layer 13: 12.7 microns at i; 50.8 microns (0.5 to 2.0 thousandths of an inch), preferably 25.4 microns (1.0 thousandths of an inch), adhesive layer 14: sufficient to ensure adhesion, he! 9 layer of paper; 38.1 microns to 63.5 microns (1.5 to 2.5 thousandths of an inch), preferably 50.8 microns (2.0 thousandths of an inch), fluorinated polyethylene layer 16; 88.9 microns to 05 127 microns (3.5 to 5.0 thousandths of an inch), preferably 101.6 microns (4.0 thousandths of an inch) '.

The upper fluorinated polyethylene layer 16 is bonded to the paper layer 15 by applying sufficient heat and pressure to the substrate. Where the application of heat and pressure is inappropriate, an appropriate adhesive should be used.

Figure 2 is an example of the layered structure of a collapsible container in which the layers are designated as in Figure 1, the layer 11 being the innermost and the other layers being made of the same materials and being placed in the same order as indicated. It is clear from the above that the Applicant has provided a collapsible container structure which significantly reduces the problems not solved hitherto by the prior art. The laminate substrate and the laminate shoulder piece substantially suppress product penetration and oxygen absorption.

The outer layer of fluorinated polyethylene is a thermoplastic material capable of melting during a lateral welding operation and ensuring adequate protection for the paper and the intermediate layer of metal foil. The technique of welding a collapsible toothpaste tube of the general type described herein is found in the U.S. patent. A. No. 3.2S5.725, incorporated in the present document for reference. However, the outer layer of fluorinated polyethylene and paper can be removed if the barrier sheet 35 has a thickness sufficient to resist damage, and by flowing a thermoplastic material in the side overlap weld during sealing. ° of it when using such a system.

In addition, the inner layer may be paper in a 3-layer laminate formed from paper, metal foil and fluorinated polyethylene as described. Since the outermost and innermost layers are preferably the same, the folded edges of the tube produced from the substrate are conveniently bonded by heat. A suitable adhesive can be used when heat bonding is not possible. This variant is in addition to the 4-layer laminate mentioned above, consisting, from the outside to the inside, of fluorinated polyethylene, paper, a metal foil and fluorinated polyethylene.

It is envisaged to use if necessary between the layers of the appropriate adhesives. Fluorinated polyethylene can also be used, if desired, for shoulder pieces, plugs, necks, it pistons and in the manufacture of dispensing valves for other toothpaste dispensers, in particular in the interior parts exposed to the toothpaste contained, and we will naturally use here again, if necessary, compatible adhesives.

In addition, when cast as a film on the inner faces of plywood drums used for storing scented toothpaste, the material will retard the loss of aroma in the drums, thereby extending the shelf life.

Λ (I -!

Claims (6)

11 1. Substrate composed of layers of materials, characterized in that it comprises a first layer (11) of fluorinated polyethylene, a second layer (13) 05 of metallic foil, a third layer of paper (15) and a fourth layer (16) of a fluorinated polyethylene. 2. Substrate according to claim 1, characterized in that the first layer of fluorinated polyethylene is fixed on the metal sheet with an adhesive. 3. Substrate according to claim 1, characterized in that the third layer of paper is fixed to the fourth layer of fluorinated polyethylene with an adhesive. 4. Substrate according to claim 1, characterized in that the first layer of fluorinated polyethylene is fixed on the metal sheet with an adhesive and in that the third layer of paper is fixed on the fourth layer of fluorinated polyethylene with an adhesive . 5. Substrate according to claim 4, characterized in that the adhesive is a copolymer of ethylene and acrylic acid. 25 6. Crushable paste dispenser container, characterized in that it is formed using a substrate as claimed in any one of the preceding claims. ........ Λ d / 4 AC A t * oc as <SS! / '