LU86230A1 - SUBSTRATE CONTAINING POLYPROPYLENE AND CONTAINER COMPRISING APPLICATION - Google Patents

Description

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The present invention relates generally to container technology and, more particularly, to a collapsible dispensing container whose wall is laminated in the body portion thereof, whereby penetration and absorption of the product, and absorption of oxygen are avoided in one; to a large extent in all regions of the container structure which are sensitive to it.

1 Crushable tubes formed from loose metal and plastic materials have been known for a long time in the field of packaging. The extruded metal tubes are inherently brittle, and their repeated use frequently leads to cracks in the wall, so that the product exudes from a place other than the substantially rigid dispensing orifice. Among the metal tubes of the prior art, aluminum tubes, although probably the least brittle, have quite limited applications, because so far it has not been possible to apply to their interior surfaces a completely satisfactory coating, 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 ! of the relatively brittle nature of 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 has been noted that some other products deteriorate after some time when contained therein.

Plastics such as polyethylene are permeable in! Î: to some extent when used in the wall thicknesses used in tubular containers and the essential oils contained in most toothpastes to scent them their size is reduced during storage of the container, which makes the dentifice less palatable. Likewise, the wall. of the plastic container absorbs oxygen over time, and can ultimately decompose the product, which 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 some penetration of the product and absorption of oxygen through the body of the tube, and in particular when the internal thermoplastic layer is a copolymer of With ethylene and a polar group-containing monomer which is copolymerizable therewith, the possibility of product deterioration remains, although to a much lesser extent.

35 Attention is drawn to the following prior art: -v.

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Marchak (Canadian Patent No. 728,525 describes a laminate tube containing an inner layer of polyethylene.

He recognizes the problem of odoriferous oil being absorbed by the thermoplastic wall and suggests the use of nylon to solve it.

Herrero (U.S. Patent No. 4,139,665) describes a laminate that does not contain metal. This laminate uses, among other things, polypropylene as an inner layer, to act as a barrier against humidity and water vapor. A thermoplastic copolymer of acrylonitrile serves as a flavor barrier. This laminate is different from the present invention in that it does not contain a metallic foil. In addition, Herrero does not recognize the effectiveness of polypropylene as a barrier for the aromas.

Yoshio et al. (US Patent No. 3,958,721) describe a collapsible laminate tube which does not contain (either metallic foil. Although this tube contains polypropylene, they note that the low odor permeability <20 and high oil resistance are provided by the polyvinyl alcohol film.

None of the references cited above specifies polypropylene as the inner layer of collapsible laminate tubes containing metal sheets. In the cases where polyolefins are mentioned, the resistance to the absorption of odoriferous essential oils is not indicated. In fact, the problem posed by polyethylene is that of its strong absorption of aromas.

It has been shown here, surprisingly, · 30 that polypropylene, a chemical closely related to polyethylene, is practically non-absorbent for odoriferous oils. The tube contains polypropylene as the innermost and outermost layers, paper, aluminum foil and adhesive as intermediate layers.

One of the important objects of the present invention is to provide a collapsible dispensing container having a laminated wall in the body portion.

Another object of the invention is to provide a tubular container comprising several adherent layers in its body part, one of these layers, such as a metallic layer, constituting a barrier to the migration of the product and to the absorption of oxygen, and another of these layers being polypropylene or a copolymer or a mixture based on one of these of variable density and crystallinity. This last layer 10 being the most internal and preferably the most external with various additional layers sandwiched between them.

These additional layers include paper and a suitable adhesive and bonding agents such as a copolymer of ethylene and acrylic acid. The collapsible dispenser container of this; The invention can be made from the laminate substrate of the present invention by means of ordinary and known apparatus. Examples of this apparatus and method can be found in the U.S. patent.

No. 3,832,964, incorporated into the present document for reference.

Another object of the present invention is to provide a method of manufacturing laminate tubes 25 in which a tubular body 10 is formed of a barrier layer and of polypropylene or a co-polymer thereof laminated thereon. ci, the laminated tube body is then placed on a shaping element, in position adjacent to a barrier element also disposed thereon.

Other objects and advantages of the invention will become more apparent on reading the description which follows, given solely by way of example, and made with reference to the accompanying drawings.

35. In the drawings, in which the same reference numerals are used to designate identical parts: Figure 1 is a sectional view of a fragment of a laminate substrate of the present invention, Figure 2 is an elevation side view of a collapsible dispenser container realizing the 05 new concepts of the invention, parts of the walls of the body being torn off to more fully illustrate the laminated structure.

The thermoplastic material of the invention is polypropylene.

Referring first to Figure 1 of the drawings, a substrate 10 is shown in cross section, thereby revealing the constituents of the sandwich which form the laminate structure.

It will be noted that the lower layer 11 15 is a polypropylene. The second layer 12 above it is an adhesive layer which joins the polypropylene layer 11 to a third layer 13 which is a metal sheet such as aluminum foil. The fourth layer 14 is another adhesive which adheres the other side of the metal foil layer 13 to a layer of paper 15. The upper layer 16 is polypropylene.

Polypropylene is particularly useful because it has very reduced flavor absorption characteristics, as shown in the following tables, in which polypropylene is compared with polyethylene, the thicknesses of the layers or coating being the same: * f v 6 TABLE 1

ABSORPTION BY POLYMERS OF AN UNDILUTED ODORIFYING OIL

Absorption%

05 Polypropylene Tenite 4230 G

(Eastman). 1.3

Polypropylene F 120 F

(United States Steel) 1.6

Polypropylene FP 200 F

10 (United States Steel) 2.3

Polypropylene Vestrolen P 3200 (Huis Plastic) 2,3

Low density polyethylene

Tenite 154 (Eastman) 5.5 15 Low density polyethylene

Anpolen 1804 H (BASF) 5.6 + 0.14 <»

TABLE II

LOSS OF TOOTH FLAVOR;

20 PERFUME IN POLYMERS

j [Per: e aroma * t '

I Polypropylene Tenite 4230 G

(Eastman) 31

25 Polypropylene F 120 F

(United States Steel) 38

Polypropylene F 200 F

(United States Steel) 38

Low density polyethylene, 30 Lupolen 1804 H (BASF) 100 d Low density polyethylene | Tenite 154 (Eastman) 130; * Compared to the low density polyethylene of 35 BASF, arbitrarily set as equal to 100; the longer the | number is small, minus the amount of aroma lost by | toothpaste is important.

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TABLE III

RELATIVE AROMA ABSORPTION IN POLYMERS FROM A PERFUMED TOOTHPASTE3 *

22.2 ° C 32.2 ° C 48.9 ° C

05 Aluminum 0 0 0

Polypropylene FP 200 F

(United States Steel) 34 51 55

Polypropylene F 120 (United States Steel) 55 68 73 10 Low density polyethylene 6560 (ARCO) 76 76 83

Low density polyethylene NPE853 (Norchem) 69 76 104

Low density polyethylene 15 Lupolen 1804H (BASF) 100 ± 19 107 t 14 119 ί 10 * All numbers are relative to low density polyethylene of BASF, set as 100 to 22.2 ° C; the lower the number, the less the amount of absorbed flavor.

In the invention: yes, the adhesives contemplated may 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 an aluminum sheet.

The layer of paper is advantageously kraft paper.

The thickness range of each of the layers is as follows: polypropylene layer 11: 12.7 to 76.2 microns (0.5 to 3 thousandths of an inch), preferably 25.0 microns (1.0 thousandth of an inch), 35 adhesive layer 12. Sufficient to ensure adhesion, metal foil layer 13: 12.7 microns to // 8 \ 50.8 microns (0.5 to 2 thousandths of an inch), preferably 25.4 microns (1.0 thousandths of an inch), adhesive layer 14. Sufficient to ensure adhesion, 05 layer of paper 15: 38.1 to 63.5 microns (1.5 to 2.5 thousandths of an inch) , preferably 50.8 microns (2.0 thousandths of an inch), polypropylene layer 16: 88.9 microns to 127 microns (3.5 to 5.0 thousandths of an inch), preferably 10,101.6 microns (4 , 0 thousandths of an inch).

! The outermost polypropylene layer 16 adheres to the paper layer 15 by applying sufficient heat and pressure to the substrate. In cases where the application of heat and pressure is inappropriate, a suitable adhesive should be used. Figure 2 is an example of the layered structure of a collapsible container, the layers being designated as i in Figure 1, the layer 11 being the innermost and the other layers being made of the same materials [20 and placed in the same order as indicated. · [It is evident from the foregoing (j that the Applicant has provided a collapsible container structure which significantly reduces the problems not previously resolved by the prior art. The laminate substrate and a shoulder piece and barrier, practically suppress product penetration and oxygen absorption.

The outer layer of polypropylene is a | thermoplastic material capable of melting during a lateral welding stage and providing adequate protection for the paper and the intermediate layer of metal foil. The technique of welding a tube, - of crushable toothpaste of the general type revealed here is described in the patent of E. ü. A. K ° 3.295.725, incorporated in this memo for reference. However, the outer layer of polypropylene and paper can be removed if the barrier sheet has a thickness sufficient to resist damage, and by flowing a thermoplastic material in the side overlap weld during its sealing when using such a system.

05 In addition, the outer layer may be paper in a three-layer laminate formed from paper, metal foil and polypropylene and one of its copolymers as described. Since the outermost layer and the innermost layer are preferably the same, the folded edges of the tube produced from the substrate are convenient to bond by heat.

A suitable adhesive can be used when heat bonding is not possible. This variant is in addition to the above-mentioned four-layer laminate, made from the outside to the inside of polypropylene, paper, metal foil and polypropylene. It is envisaged to use, if necessary, suitable adhesives between the layers.

! Polypropylene can also be used for shoulder pieces, plugs, necks, pistons and in the construction of dispensing valves for other toothpaste dispensers, especially in the interior parts exposed to the contained toothpaste, and here still, compatible adhesives will naturally be used.

In addition, when cast as a film on the interior surfaces of plywood barrels used for the storage of scented toothpaste, the material will retard the loss of aroma in the barrels, thereby extending the storage life.

Claims (6)

1. Substrate composed of layers of materials, characterized in that it comprises a first layer (11) of polypropylene, a second layer (13) of a metallic foil 05, a third layer (15) of paper and a fourth layer (10) of polypropylene. 2. Substrate according to claim 1, characterized in that the first layer of polypropylene is fixed to 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 polypropylene with an adhesive. 4. Substrate according to claim 1, characterized in that the first layer of polypropylene is fixed to the metal sheet with an adhesive, and in that the third layer of paper is fixed to the fourth layer of polypropylene with an adhesive. 5. Substrate according to claim 4, characterized in that the adhesive is a copolymer of ethylene and acrylic acid. 6. Crushable dough dispensing container, characterized in that it is formed with the aid of a substrate as claimed in any one of the preceding claims. -. .4 ‘1„ .AZu y} a • v Λ S __. ·. _ OC- jtQ. s f. '1 · fi if 1 / r L · V. / î. t £ ..: ï- - - Y /