DE2337232A1 - FILM-LIKE COMPOSITE MATERIAL FOR THE MANUFACTURING OF PACKAGING FOR OILY SUBSTANCES AND PROCESS FOR ITS MANUFACTURING - Google Patents

Description

DR. INQ. HANS LICHTI DIFL.-INQ. HEINER LICIITI

KARLSRUHE - DURLAClI QRÖTZINQF.R STRASSE 61

TE Li.FON (0 7f i) i 11 24

18th July 1973

2631/73

i.a. Robinson (Canada) Ltd. , 69 Laird Drive Toronto 17, Ontario, Canada

Foil-like composite material for the production of packaging for oily substances and processes its manufacture.

The invention relates to flexible film-like composite material for the production of packaging for oily or fatty substances, especially for engine oil, and a process for its production.

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Polyethylene films have, due to their flexibility, Transparency, low moisture and vapor permeability, its resistance to the effects of many chemicals and similar properties Found widespread use as wrapping and packaging material for many commercial items. However is Polyethylene film permeable to oil and therefore unsuitable for packaging oily materials such as motor oil.,

There are already proposals to improve the resistance of polyethylene films to oil and similar substances been made, e.g. by applying a coating of vinylidene dichloride polymer, such as e.g. 3. Saran, on that Polyethylene film used as a barrier against penetration of oil works. Such a two-layer film is for example in the Canadian patent 797.904 'of Union Carbide C. corporation, issued October 29, 1968.

However, it has been found that such a polyethylene film laminated with a coating has disadvantages, which makes them unsuitable for packaging engine oil and the like. In particular, it was found that the coating with Polyvinylidene dichloride polymer on the polyethylene film in sufficient thickness to prevent the penetration of oil in the to prevent essential, has the consequence that the polyethylene loses its elasticity, embrittles and tears tends, so that a packaging for motor oil made of such a laminated polyethylene film tears easily. It is also difficult to produce the required tight weld seams in the manufacture of a bag from the laminated film and the welds produced in this way tear open easily. As a result, two-layer films are made of this type of film

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Bags containing motor oil fail a certain standard drip test, i.e. they tear easy when they are filled and from a certain level on they start to drip; have such bags That is why it has not found its way into the oil industry. To a To obtain sufficient resistance to the penetration of oil, the thickness of a vinylidene dichloride polymer coating would have to be obtained be considerable, which - as already mentioned - the elasticity and flexibility of the polyethylene film greatly diminishes.

In contrast, the invention proposes a film-like composite material which is used for the production of packaging for alie or fatty substances, especially for engine oil is suitable, which has a high resistance to the penetration of. Oil possesses the drip test without tearing the wall or the welds of a bag made from it, and which can be processed on conventional packaging equipment, i.e. properties owns, - z.3. also sufficient rigidity - that it is in commercial packaging equipment, such as those used conventionally for packaging milk in bags, is manageable with a minimum of change effort.

According to the invention, as a film-like composite material for the production of packaging for oily substances, A multilayer film has been proposed, in particular for motor oil, with two outer layers of solid polyethylene film and at least one inner layer embedded between these and made of a dried emulsion of vinylidene dichloride polymer, those with the inner surfaces of the polyethylene film layers is firmly connected, with the various

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Layers are of substantially uniform thickness.

The invention also proposes a method of manufacture of the film-like composite material, or more specifically the multilayer film serving as such, after which on a first polyethylene film an aqueous emulsion of Polyvinylidene dichloride is applied and left to dry, whereupon a second polyethylene film with a Glue between it and the dried emulsion coating is pressed hot on the first.

The polyethylene films that can be used according to the invention as the outer layers of the multilayer film, are not limited in terms of their chemical character to unmodified polyethylene, such as low-pressure polyethylene, but can preferably also consist of copolymers, such as those of mixtures of ethylene, propylene or butene monomers or polymers are obtained. The preferred polyethylene to be used is a copolymer of Ethylene and butene and a trade mark M 1 or M 3 from E.I. Du Pont de Nemouis & Co. traded Film provides a multilayer material with high toughness and elasticity that is oil-tight - even when hot

- is and has good sliding properties, so that from it The multilayer film produced is easy to process on conventional packaging machines. Preferably consists in the production of packaging, e.g. bags, the inside layer of the multilayer film from M 1 film, which has lower lubricity, while the outer layer consists of M 3 film of higher lubricity. the Polyethylene films should suitably have a thickness on the order of 0.025 to 0.125 mm, preferably 0.05 to

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0.10 mm, with the inside film being useful a thickness of about 0.075 mm, the outside film should have a thickness of 0.05 mm. Overall, the Thickness of the multilayer film should not be more than about 0.18 mm.

It is of crucial importance for the invention that the covering of vinylidene dichloride polymer from a aqueous emulsion is left that contains 30% to 60% solids. As representative examples of useful Copolymers of vinylidene dichloride for the purposes of the invention are those with the following body classes:

Acrylonitrile, methacrylonitrile, methyl acrylate, Ethyl acrylate, butyl acrylate, isobutyl acrylate, Methyl methacrylate, ethyl methacrylate, butyl methacrylate, isobutyl methacrylate, methyl vinyl ketone, vinyl acetate, Vinyl chloride, styrene, dichloro yinylidene chloride, chloroprene and butadiene.

In general, the copolymer should not contain less than 50% by weight of polyvinylidene dichloride.

A suitable vinylidene dichloride copolymer is the product Saran, which is in the form of an emulsion under the Designation "Daran" (Dewey and Alny) is available. The emulsion is expediently in an amount of 0.34 to 1.34 kg

2 2

applied per 100 m, preferably 0.50 to 0.67 kg per 100 m of the polyethylene film. When used in lesser

2
Amount than 0.34 kg / 100 m of the polyethylene film, it has been found that the barrier effect of the film against the penetration of oil is decisively deteriorated while in use

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If the amount is greater than 1.34 kg / 100 m, the film tends to become brittle, tears open easily and is not easy to handle on conventional packaging machines.

It has been found that the inner layer is made of vinyl dichloride polymer as a remaining covering of dried emulsion between the outer layers of the multilayer film other types of internal covering of vinylidene dichloride polymer for use as a barrier layer is superior «For example, it has been found to be difficult when the inner layer is considered to be left behind from solution Deposit is formed to remove the solvent from the polyethylene film forming the outer layer, and then at When the covering dries, some solvent remains in the multilayer film. So there could be a residue: solvent the bond between the layers of the multilayer film adversely affect and / or affect the content of bags formed from the multilayer film, since many solvents have an adverse effect on engine oil and the like. It is also used in the manufacture of the inner layer a solution necessary to remove the solvent in the usual way by heating. Through such bake-out, the polyethylene film destroyed and the expelled solvent undesirably pollutes the surrounding atmosphere. On the other hand, it was also found that when the inner layer from the emulsion it is possible to apply a higher quantity of solids from the dried Emulsion and dar.it to obtain a heavier coating in a single application, resulting in a better barrier effect for oil with a smaller thickness of the vinylidene dichloride polymer layer has the consequence.

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Also joint extrusion of the multilayer film and especially the extrusion of molten vinylidene dichloride polymer results in the same amount of material a less effective barrier to oil compared to the emulsion. In particular, it is normally the case with such coextrusion It is necessary to add a plasticizer to the inner layer of polyvinylidene dichloride, which, however, reduces its oil barrier effect decreased. Such a plasticizer is not necessary for a barrier layer made of polyvinylidene dichloride emulsion. It is also difficult to obtain a coating of small thickness by coextruding, and it is impossible when common extrusion printing the inner surface of the outer layers of polyethylene to provide what naturally desirable and easy in the method of emulsion coating with polyvinylidene dichloride of the present invention is possible.

The production of the multilayer film from films corresponding Materkls has the disadvantage that the possibly according to the polyvinylidene dichloride film to be used It is difficult to handle other electrostatic charges attached to it. Also requires the polyvinylidene dichloride film usually a plasticizer, which, however, as stated above, reduces its oil barrier effect. After all, that is Fo Ii s draw one for the production of the multilayer film elaborate 'procedure.

It is to be regarded as a very essential feature of the invention that the polyvinylidene dichloride coating that the inner layer forms ^ is embedded between two outer layers of sturdy polyethylene. The two outer ones

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Layers give the multilayer film a good Flexibility so that it can be subjected to the above-mentioned drip test able to withstand «The additional outer layer made of polyethylene mediates in the manufacture of bags on conventional Packaging machines have good flexibility and water tightness, regardless of whether the corners overlap be welded, or whether the tube from which the bags are made is glued with an adhesive film, since the two outer layers of Folyaethylene are welded together by means of a weld seam. The one across the so shaped The tube-running weld seam for forming and separating the bags from the tube is also one of the outer layers of polyethylene connecting seam, which in turn is a soft, pliable weld seam. These soft supple Weld seams of the filled pouch packs give them a high level of resistance to breakage and tearing during transport, e.g. during their shipment · It was further found that the outer layer made of polyethylene, which is itself oil-permeable, but the barrier effect of Multi-layer film against oil improved.

Although the aqueous emulsion of the vinylidene dichloride polymer applied directly to the polyethylene film to produce the covering from dried emulsion can be, but the bond of the dried emulsion coating to the polyethylene film can turn out different and in In some cases it is therefore advisable to apply an adhesive primer to provide for the binding of the dried polyvinylidene dichloride emulsion to improve the polyethylene film. The adhesion primer not only causes the Bond between dried emulsion coating and polyethylene film better, but also that it should be even. Suitable

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Primers are known in the art and are described, for example, in: ■

U.S. Patent 833,494, National Distillers, dated February 3, 1970 U.S. Patent 3,231,411, R.B.TyIe et al., V. January 25, 1966 U.S. Patent 3,968,576, Keller et al., V. January 17, 1961. ·

To improve the bonding or adhesion of the coating made of ^{;:; i} dried poly-vinylidene-dichloride emulsion to the film, it can also be exposed to radiation before the foundation is applied.

The <3rundierung can be applied to the polyethylene film by means of a scooter or the like. be applied. A suitable primer is, for example, an isocyanate prepolymer, such as one marketed under the designation NA 141 K by Talon Adhesives Corporation.

Adequate ^ adhesion between the outer " The polyethylene layer and the emulsion layer can be achieved by applying an adhesive, preferably to the layer provided with the dried emulsion coating an oil-resistant adhesive such as those well known in the art and, for example, in U.S. Patent; 3,445,324 dated May 20, 1969. The adhesive "is expediently a crosslinked polymer, e.g. a polyester adhesive. The Glue is expediently in an amount of 0.17 to 0.67 kg / 100 m, preferably 0.17 to 0.34. kg / 100 m of the polyethylene film is applied. A particularly suitable adhesive is under the trade name "Unoflex" from the Polymer .. Industries Inc. placed on the market. . . · ... ■ -

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According to a first embodiment of the invention, a single coating is a dried polyvinylidene dichloride emulsion applied to the inner surface of one of the polyethylene films, expediently after priming and firmly bonded to the other polyethylene film by means of an adhesive.

According to another embodiment sfornwier invention are

'■ * ■'"· the inner surfaces of both polyethylene films, expediently provided with a coating of dried polyvinylidene dichloride emulsion after application of an adhesive primer and an adhesive is introduced between the dried emulsion coverings. The second cover made of dried polyvinylidene dichloride emulsion naturally improves the barrier effect of the multi-layer film against the penetration of oil and the like, however, increases the production costs of the same. To produce such a multi-layer film, the process for producing it must be modified in that both polyethylene films are provided with a coating of dried polyvinylidene dichloride emulsion must be, whereupon the adhesive is introduced into the multilayer film between the two dried emulsion layers.

Although the flexible composite material according to the invention is primarily used for packaging oily or fatty substances, As · Β · motor oil is intended, it can of course be used more generally for packaging other materials, e.g. Can be used for vacuum packaging of food, such as cheese or meat, as it has a good barrier effect for moisture and gas unfolds

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The invention is illustrated below with the aid of the examples. each explained in connection with the associated drawing.

example 1

A roll of polyethylene film approx.0.075 mm thick, (M 1 from E.I. Dupont de Nemours) is exposed to radiation treatment by corona discharge on one side and then passed through a coating machine in a first coating station. In the coating machine, an application roller rotates in a basin that a solution of a primer (NA 141 K from Talon Adhesive Corporation), namely an isocyanate prepolymer, and applies this to the pretreated side of the film. Excess solution is then removed by a with Qaht wrapped rod and the primed film then happens a tunnel in which it is dried by warm air. The primed film is received in a second coating station Then, in a similar manner, an application of a 50% solid polyvinylidene dichloride ("Daran 225") containing aqueous

Dispersion, which is applied in such an amount that the

• 2

then dried topping 0.5 kg "Daran 225" per 100 cn contains. The coated film is then rolled up.

A 25% solids solution of a thermosetting adhesive ("Unoflex" from Polymer Industries, Inc.) in one Mixture of toluene and ethyl acetate is applied to the layer side of the coated film by means of an engraving cylinder applied and the solvent removed in a drying tunnel j the adhesive solution is applied in such an amount that

that a dry adhesive layer of about 0.25 kg / 100 m

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remains behind. At the exit from the tunnel the coated Film brought into contact with that irradiated from a corona discharge Side of a polyethylene film about 0.05 mm thick (M 3 from E.I. Dupont de Nemours) and made in such a way obtained flexible film is through the nip one of a rubber roller and a steel roller, the latter on a Temperature of 85 ° C, heated, existing roller pair happened. The multilayer film then remains for at least Left to age for 24 hours for the purpose of hardening the adhesive and the roll is then cut into suitable dimensions for the production of packaging units for conventional machines for packaging oil, as in US Pat. No. 2,260,064 described.

Example 2

The multilayer film is produced in a manner similar to that in Example 1, but instead of the 0.05 mm film made of polyethylene (M 3), a film of 0.075 mm thickness [is used, which before contact with the adhesive-coated film on the latter facing side with a dried covering made of an emulsion of poly-vinylidene

j dichloride ("Saran 225") in a manner similar to Example 1

is coated in an application thickness of 0.5 kg / 100 m.

The drawing shows schematically:

Fig. 1 shows a first embodiment of a multi-rail

film, in longitudinal section, according to example 1 |

2 shows a second embodiment of the multilayer film, likewise in a longitudinal section, correspondingly

j Example 2.

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The upper polyethylene film 10 is on our part with one,. Primer 11 provided, on which a layer 12 of dried polyvinylidene dichloride emuläon is applied · The Lower polyethylene film 10 * is on top with an adhesive layer 13 provided, which mediates the adhesion to the emulsion layer 12 and thus to .die polyethylene film 10.

In Pig. 2 20, 20 * denote the two outer polyethylene films, 21, 21 * the primer applied to both, 22, 22 'the emulsion layer of dried polyvinylidene dichloride emulsion applied to each polyethylene film over the primer and 23 the adhesive layer between them.

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Claims (1)

- 14 - 2631/73 Claims ) Foil-like composite material for the production of packaging for oily or greasy substances, e.g. engine oil, characterized by a multilayer film with two outer layers of solid polyethylene film and at least an inner layer of a dried emulsion of polyvinylidene dichloride, which is attached to the inner surfaces of the polyethylene film layers is firmly bonded, the layers being of substantially uniform thickness 2 · composite material according to claim 1, characterized in that one of the outer layers on its inside by means of an oil-resistant adhesive is connected to the inner layer of dried polyvinylidene dichloride emulsion. 3. Composite material according to claims 1 and 2, characterized characterized in that the other outer layer of polyethylene film with the inner layer of dried polyvinylidene dichloride is connected by means of a primer effective as an adhesive. 4. Composite material according to claim 1, characterized in that each of the outer layers of polyethylene film is provided with a coating of dried polyvinylidene dichloride emulsion on the inside, and that the composite layers thus obtained are connected to one another by means of an oil-resistant adhesive arranged between the emulsion layers . - 15 - 409807/0786 - 15 - 2631/73 5. Composite material according to claim 1, characterized in that *, that the outer layers of polyethylene film have a thickness in the range from 0.025 to 0.125 mm and that the Layer of dried polyvinylidene dichloride emulsion has a mass of 0.5 kg to 1.0 kg of polymer resin per 100 m of the composite material. '· 6. Composite material according to claim 1, characterized in that the outer layers of polyethylene film have a thickness in Range between 0.05 mm and 0.100 mm and that the layer of dried polyvinylidene dichloride emulsion has a mass of 0.34 kg to 0.67 kg of polymer resin per 100 m of the composite material. 7. Composite material according to claims 5 and 6, characterized in that that the multilayer film has a total thickness of not more than 0.18 mm. 8. Composite material according to one of claims 1 to 7, characterized characterized in that the polyethylene film consists of a copolymer of ethylene and butylene. 9. Packaging for oily or fatty substances, e.g. Motor oil, characterized in that it consists of composite material according to one of Claims 1, 2 or 3. 10. A method for producing the composite material according to claim 1, characterized in that on a first Polyethylene film is an aqueous emulsion of polyvinylidene dichloride applied, then dried to form a coating on the polyethylene film, followed by a second, on its inner, the first polyethylene film - 16 409807/0786 - 16 - 2631/73 facing surface with an adhesive, polyethylene film is brought into contact with the first ^. . j ■ 11 · The method according to claim 10, characterized in that on the inner surface of the second polyethylene film before applying the adhesive an aqueous emulsion of polyvinylidene dichloride is applied and dried 12. The method according to claims 10 and 11, characterized in that an aqueous emulsion of polyvinylidene dichloride with at least 50% dry residue is used. 13. The method according to claims 10 and 11, characterized in that the adhesive used is oil-resistant, preferably an oil-resistant, thermosetting synthetic resin 14. The method according to claims 11 and 12, characterized in that the first polyethylene film prior to application the emulsion is provided with a primer 15. The method according to claims 10 and 11, characterized in that the aqueous emulsion of polyvinylidene dichloride is an aqueous emulsion of saran 16. The method according to claims 10 and H _9, characterized in that each of the Polyaethyienf Umschichten has a thickness of 0.025 to 0.125 mm and the emulsion is brought in an amount of 0.34 to I ₉ 34 kg per 100 m of the composite material. . 17 «Process according to claims 10 and 11, characterized in that the polyethylene is a Copolymexisat of Is ethylene and butylene. ^Wra 409807/0786