FI85121C - Fluorinated polyethylene laminated container - Google Patents

Description

1 85121

This invention relates generally to the container field, and more particularly to a collapsible dispensing container having a body laminated wall structure that prevents the passage and absorption of a product in substantially all sensitive areas of the container.

The packaging industry has long known for collapsible tubes made of metal and plastic materials. Extruded metal tubes are inherently brittle and repeated use often results in cracks in the wall so that the product exudes from a location other than a substantially rigid dispensing opening. Of the prior art metal tubes, aluminum tubes, although probably the least brittle, have somewhat limited applications, as it has not hitherto been possible to apply a completely satisfactory coating to their inner surfaces when it is required to prevent alkali and acidic corrosion of the metal and contamination of the contents of the reaction products. Despite the relatively fragile nature of the metal tube, said internal coating operation requires an additional process step, which necessarily increases the cost of the final product.

Tubes formed of polyethylene and other plastic materials have enjoyed general commercial success in the packaging of many products; certain other products have been found to degrade after a certain period of time when they are included. Plastics, such as polyethylene, are to some extent permeable when used as wall fillings used in tubular containers, and the volume of essential oils contained in most toothpastes for seasoning decreases during container storage, making toothpaste less desirable. Likewise, the wall of the plastic container absorbs oxygen over time and can eventually decompose the product, as has actually been observed with fluoride 2 85121 toothpastes. An additional disadvantage of a plastic tube is that the surface is not easily able to receive printing or decorative material. In addition, the plastic tube created by 11a, exemplified by polyethylene, has a memory effect; i.e., they do not remain compressed when compressed, which is a particular disadvantage of toothpaste tubes.

to counter the above problems, it has therefore been proposed to attach a metal foil barrier layer between the product and the body of the polyethylene tube. This alleviates the compressibility problem so that the metal layer would give its compressibility to the plastic. In addition, a metal foil barrier layer between the product and the body of the polyethylene tube would prevent said loss of essential oils and oxygen absorption. A metal barrier layer has been proposed as an intermediate layer between opposing polyethylene films and to form the laminate by heat with or without suitable adhesives. However, although such a structure is effective in preventing the passage of the product and the absorption of oxygen through the tube body to some extent, and especially when the inner thermoplastic layer is a copolymer of ethylene and a polar group-containing monomer copolymerizable therewith, decomposes, albeit to a much lesser extent.

: Attention is drawn to the following prior art: · U.S. Pat. No. 3,295,725 has developed a tube which combines the above advantages of an aluminum tube and a plastic tube. This is a laminated, collapsible dispensing container that includes both a metal barrier and a polyethylene inner wall. The thermoplastic layer is generally described as a polyolefin and a copolymer ____: formed by an olefin and a polar group-containing monomer copolymerizable therewith. This laminate avoids the limitations described above except for the absorption of essential oils from toothpastes.

CA Patent 728,525 also develops a laminated tube that * -. contains an inner layer of polyethylene. Here, there is a recognized problem that the thermoplastic wall absorbs spice oil.

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Other patents have examined surface-treated polymers in their articles of manufacture (U.S. Patent 4,142,032). When examining films and containers, it was found that barrier properties are improved when surface-treated with both fluorine and bromine. However, no tube was made here; this product did not contain aluminum; and there was no awareness of the aroma barrier properties of this polymer.

U.S. Patents 4,292,151, 4,110,518, 4,020,223, 3,647,613 and 4,404,256 also contained articles of manufacture comprising fluorinated surface-treated polymers. U.S. Patent No. 4,292,151 showed that the treatment made the surfaces susceptible to adhesives, coatings, paints, spices, decorations, etc .; U.S. Patent 4,110,518 showed that the surface behaves as an electrical insulator; The treatment of U.S. Patent 4,020,223 gave oil stain removal properties; and the treatment of U.S. Patent 3,647,613 provided solvent resistance. However, none of these products were a tube; nothing contained a layer of aluminum; and none of these patents found the flavor of these products.

Therefore, it is an important object of the present invention to provide a collapsible dispensing container having a laminated wall structure in the body portion.

Another object of the present invention is to provide a tubular: container having a plurality of adhesive layers in a body, one of said layers providing a barrier to product migration and oxygen absorption, such as a metal foil, and the other of said layers being fluorinated polyethylene or a mixture thereof; whose density and crystallinity vary. The latter layer is inwardly and preferably outermost with various additional lamellae being sandwiched between them.

:: Such additional layers include paper and suitable adhesives and binders, such as a copolymer of ethylene and acrylic acid.

4 85121 The collapsible dispensing container of the present invention can be formed from the laminated substrate of the present invention by conventional and known devices. Examples of such an apparatus and method can be found in U.S. Patent 3,832,964, which is incorporated herein by reference.

Another object of the present invention is to provide a method of making laminated tubes, wherein the tubular body is formed of a barrier layer and fluorinated polyethylene laminated thereto; the laminated tube body is then placed on the forming member against a barrier layer member also disposed thereon.

Other objects and advantages of the present invention will become more apparent as the description proceeds.

In the drawings, in which the same numerals are used to refer to the same parts in both: Figure 1 is a cross-sectional view of a small portion of the laminated substrate of the present invention, Figure 2 is a side elevational view of a collapsible dispensing container incorporating the novel ideas of the present invention.

The thermoplastic of this invention is fluorinated polyethylene.

Referring now first to Figure 1 of the drawings, there is shown a cross-section of the base 10 which reveals the components of the slice structure required to form the laminated structure.

It is found that the bottom layer 11 is fluorinated polyethylene. The second layer 12 on top of it is an adhesive layer connecting the fluorinated polyethylene layer 11 to a third layer 13, which is a metal foil such as aluminum foil. The fourth layer 14 is a second adhesive that firmly joins the second surface of the metal foil layer 13 to the paper layer 15. The top layer 16 is fluorinated polyethylene.

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Fluorinated polyethylenes are particularly useful because they have very low flavor absorption properties, as can be seen from the following tables in which fluorinated polyethylenes are compared to polyethylene when the thicknesses of the layers or coating are the same:

table 1

Relative absorption of flavoring from polymers * flavored toothpaste__

22.2 ° C 32.2 ° C 48.9 ° C

Aluminum 0.4 0 0.4

Fluorine surface treated high density polyethylene HD-3 (Air Products) 22 37 90

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

Low density polyethylene LD-0 (Air Products) 100 94 111 * o

All numbers relative to low density polyethylene at 22.2 ° C, arbitrarily set to 100; the lower the number, the less flavor is absorbed.

Table II

Absorption of undiluted spice oil in the polymer - Absorption (¾)

Aluminum 0

Fluorinated surface treated high density. polyethylene HD-3 (Air Products) 3.3

High density polyethylene HD-0 (Air Products) 4.8

Low density polyethylene LD-0 (Air Products) 7.9

Low density polyethylene NA (USI) 10.0

Ionomer Surlyn 1707 (DuPont) 15.7

Ionomer Surlyn 1605 (DuPont) 19.0; : Ionomer Surlyn 1706 (DuPont) 24.3 6 85121

Table III

Absorption of undiluted spice oil into the polymer

Spice absorbed% No. 74 fluorine surface treated low density polyethylene a 2.6 No. 76 fluorine surface treated low density polyethylene a a 2.6

Low density polyethylene '5.5

Low density polyethylene (comparison) ^ a ^ 5.6 + 0.14 ^ e ^ • (c)

Ionomer 7.4

Ionomer ^^ 12.2 (a)

The low density polyethylene is Lupolen 1804 H (BASF)

Tenite 154 (Eastman)

Surlyn 8940 (DuPont) (d) Surlyn 8920 (DuPont) (e) n - 3.

Table IV

Loss of aroma from flavored toothpaste to polymers ★

Flavor Loss No. 76 Fluorine Coated Low Density Polyethylene α '56 No. 74 Fluorine Coated Low Density Polyethylene α' 64; Ionomer 88:: fr) - - Ionomer 96 - (3)

Low density polyethylene (comparison) 100 - - 1 / J \

Low density polyethylene '' 136 li

Relative to BASF's low density polyethylene reference sample, which was arbitrarily set to 100; the lower the “figure,” the less aroma is lost from the toothpaste.

(A) is LDPE Lupolen 1804 H (BASF)

Surlyn 8920 (DuPont) (c) Surlyn 8940 (DuPont)

Tenite 154 (Eastman) 7 85121

It is intended that within the scope of this invention the adhesives may be copolymers of ethylene and acrylic acid or methacrylic acid or their sodium or zinc salts in a diluent system.

The metal foil may preferably be an aluminum foil.

The paper layer is preferably kraft paper.

The thickness range of each layer is as follows:

Fluorinated polyethylene layer 11 to 0.013 to 0.076 mm, preferably 0.025 mm.

Adhesive layer 12 - sufficient to ensure adhesion. Metal foil layer 13 to 0.013 to 0.051 mm, preferably 0.025 mm. Adhesive layer 14 - sufficient to ensure adhesion.

Paper layer 15 to 0.038 to 0.064 mm, preferably 0.051 mm. Fluorinated polyethylene layer 16 to 0.089 to 0.127 mm, preferably 0.102 mm.

The uppermost fluorinated polyethylene layer 16 adheres to the paper layer .15 by applying sufficient heat and pressure to the substrate. In the event that the use of heat and pressure is not appropriate, a suitable adhesive must be used. Figure 2 is an example of a laminated structure of a collapsible container in which the layers are shown as in Figure 1 with layer 12 inward and the other layers being of the same materials and in the same order as shown therein.

- It is considered clear from the above that the application contains-; resulting in a collapsible tank structure that substantially reduces problems not previously solved in the art. The laminated substrate and laminated protrusion 20 substantially eliminate product permeation and oxygen absorption.

The outer layer of fluorinated polyethylene is a thermoplastic that is able to fuse together during the side-sealing step and provides adequate protection between the paper and metal foil interlayer.

The sealing technique for a collapsible toothpaste tube of the general type disclosed herein can be found in U.S. Patent 3,295,725, which is incorporated herein by reference. However, the outer layer of fluorinated polyethylene and paper can also be omitted if the foil barrier layer is of sufficient thickness to resist damage and by pouring the thermoplastic material into the adhesive side seam during sealing when such a system is used.

Further, the outer layer may be paper in a three-layer laminate formed of paper, foil and fluorinated polyethylene as described. Since the outer and inner layers are preferably the same, the folded edges of the tube formed from the base are easy to heat seal. A suitable adhesive can be used when heat sealing is not possible. This modification is in addition to the above-mentioned four-layer laminate consisting of externally internally fluorinated polyethylene, paper, foil and fluorinated polyethylene.

The intention is that suitable adhesives are used between the lamellae whenever necessary. Fluorinated polyethylene can also be used in the manufacture of dispensing valves for cantilever, cap, neck, plunger and other toothpaste dispensers, especially when the interiors are exposed to the toothpaste contained therein and again, when required, naturally occurring adhesives are used.

In addition, when the material is cast as a film on the inner surfaces of the pulp barrels used to store flavored toothpaste, it slows down the loss of flavor to the barrels, which extends the shelf life.

Various modifications of the invention are set forth herein, and these and other modifications may, of course, be made without departing from the novel ideas of this disclosure.

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Claims (6)

A container consisting of laminated material layers, the container comprising a first layer (11) of fluoridated polyethylene, a second layer (13) of metal foil, a third layer (15) of paper, and a fourth layer (16) of fluoridated polyethylene, characterized in that the layer (11) in contact with the substance in the container consists of fluorinated polyethylene. 10 851 21 Container according to claim 1, characterized in that the first layer (11) of fluorinated polyethylene is bonded to the metal foil by means of a binder (12). Container according to claim 1 or 2, characterized in that the third layer (15) of paper is connected to the fourth layer (16) of fluorinated polyethylene by means of a binder. Container according to claim 1, characterized in that the first layer (11) of fluoridated polyethylene is bonded to the metal foil (13) by means of a binder and that the third layer (15) of paper is connected to the fourth layer (16) of fluoridated polyethylene by binder. Container according to claim 4, characterized in that the binder (12) is a copolymer of ethylene and acrylic acid. Container according to any one of claims 1-5, characterized in that it is a pasteable container for dispensing material for paste. Il