WO1998036914A1

WO1998036914A1 - Plastics film, its use in processes to produce packaging containers, the packaging containers thus produced, and the use of aqueous coating compositions to coat plastics films for producing packaging containers

Info

Publication number: WO1998036914A1
Application number: PCT/EP1998/000975
Authority: WO
Inventors: Harald Borgholte; Michaela Walter; Jürgen Kaczun; Peter Eric Van Rijn
Original assignee: PPG Industries Ohio Inc; PPG Industries Inc
Current assignee: PPG Industries Ohio Inc; PPG Industries Inc
Priority date: 1997-02-22
Filing date: 1998-02-20
Publication date: 1998-08-27
Anticipated expiration: 1999-08-22
Also published as: DE19707137A1; AU6499198A

Abstract

The present invention relates to a plastics film for producing packaging containers, one side of the film being coated with a sealable coating and the opposite side being coated with a coating composition, wherein the coating composition comprises an aqueous acrylate dispersion which is obtainable by polymerization of (A) from 20 to 90 % by weight of a mixture comprising (a1) from 1 to 50 % by weight, based on the total weight of component (A), of (meth)acrylic acid and (a2) from 50 to 99 % by weight, based on the total weight of component (A), of at least one further monomer, in the presence of (B) from 9.9 to 79.9 % by weight of at least one halogen-containing polyolefin and (C) from 0.1 to 10 % by weight of at least one free-radical generator and dispersing the resultant polymerization product in water, where the percentages for components (A), (B) and (C) are based on the total weight of (A), (B) and (C).

Description

PLASTICS FILM, ITS USE IN PROCESSES TO PRODUCE PACKAGING CONTAINERS, THE

PACKAGING CONTAINERS THUS PRODUCED, AND THE USE OF AQUEOUS COATING COMPOSITIONS TO COAT PLASTICS FILMS FOR PRODUCING PACKAGING CONTAINERS

The present invention relates to a plastics film for producing packaging containers, one side of the film being coated with a sealable coating and the opposite side of the film being coated with an aqueous acrylate- based coating composition.

The present invention moreover relates to a process to produce packaging containers using these plastics films, to the packaging containers thus produced, and also to the use of the aqueous coating compositions to coat plastics films and for application over printing ink.

Plastics films which are intended for use in, for example, the packaging of foods, e.g. chocolate, ice cream, nuts, potato chips and the like, are provided with adhesive coatings in order to allow an effective seal.

In addition, plastics films of the type mentioned at the outset are also applied to packaging containers made from glass and/or plastic, for example drinks bottles, in order to mark these and/or to provide them with a decorative surface. In this case too, plastics films are provided with adhesive coatings.

The adhesive coatings in particular cases are either hot-seal able coatings, which can be sealed at elevated temperatures, or cold-seal able coatings, which are sealed at temperatures of from about 0 to 80°C. Cold-seal able coatings and their properties are described, for example, ^' by L. Placzek, in Coating, 18 (4), pages 94 and 95, 1985. Cold-sealable coatings are preferably applied from an aqueous phase. Pressure- sensitive adhesives, which are used in the cold-sealing process, are predominantly used in the packaging of foods, e.g. in packaging for chocolates and ice cream.

Sealable coating agents for the sealing of plastics films, such as polypropylene films, are known, for example, from US-A-4,898,787, US-A-4,888,395 and US-A-5,070, 164. The cold-sealable coatings are usually based on emulsion polymers which have an average molecular weight of from about 20,000 to 150,000 and a glass transition temperature of from about -15 to about +15°C.

However, cold-sealable coatings have the disadvantage of poor antiblocking properties, i.e. when stored, plastics films coated with cold-sealable coatings, if stored over a relatively long period under normal storage conditions in the form of rolls, show a tendency to stick to the mutually superposed layers of film. In addition, in the case of printed plastics films, there is also an undesirable transfer of printing inks from the outer side to the inner side coated with the sealable coating.

Cold-sealable coatings therefore require the application of a protective layer on the other side of the film. For this purpose, coatings may be applied directly to the appropriately pretreated plastics film. These coatings used for this purpose must be printable and are usually called outside coatings. In the case of printed films, printing inks are then applied to these outside coatings, either directly at the film producer or else by the user of the films. A protective coating (see above), usually called a release coat, must also be applied to the printing inks. In the case of unprinted films, as used, for example, for various industrial applications, the release coats may be applied without prior application of printing inks directly to the plastics film, which is generally appropriately pretreated.

The coating compositions for the printable outside coatings usually used either contain solvent or are aqueous and based on acrylate copolymers. The antiblocking properties are usually obtained by adding from 1 to 10 percent by weight, based on the solids content of wax and of acrylate copolymer, of a wax (added generally as wax dispersion), as described, for example, in DE-A-2440 112.

The release coats described above usually contain polyamide resins, often in combination with cellulose nitrate and with waxes, with fatty amides or with silicone oils. If low-molecular-weight silicone oils or waxes are used in the release coats, there is the danger of migration of these constituents into the sealable layer, resulting in an undesirable reduction in seal strength.

In other areas moreover, for example in the coating of wood, there is the need for substrates coated with printing inks to be provided with a protective layer.

The journal Polymers Paint Colour Journal, April 1996 issue, pages 27 28, discloses the use of si licones in release coats. This article, however, does not contain further details on the composition of the release coats. The object on which the present invention is based is therefore to provide plastics films which are suitable for producing packaging containers and have good resistance to blocking. The plastics films should moreover fulfill the requirements usually placed upon plastics films which are used to produce packaging containers. The plastics films should therefore, for example, be sealable under the conditions usually used and have a good seal strength. In addition, the coating materials/coatings used to produce the films should permit very easy sol ent recovery. The resultant films should moreover have very good optical properties. They should, furthermore, preferably be odorless, so as to be suitable also for producing food packaging containers. Finally, the plastics films should also show no transfer of printing inks when the printed films are stored in the form of rolls.

Surprisingly, this object is achieved by means of the plastics films of the type described at the outset, wherein the coating composition applied to the side opposite to the sealable coating layer comprises, as binder, an aqueous solution or dispersion of an acrylate copolymer, the solution or dispersion being obtainable by free-radical polymerization of

(A) from 20 to 90# by weight of a mixture comprising

(al) from 1 to 50# by weight, based on the total weight of component (A), of acrylic acid or methacrylic acid or of a mixture of acrylic acid and methacrylic acid and (a2) from 50 to 99# by weight, based on the total weight of component ^' (A), of an ethylenically unsaturated monomer different from (al) or of a mixture of such ethylenically unsaturated monomers, in the presence of

(B) from 9.9 to 79.9# by weight of a halogen-containing polyolefin or of a halogen-containing copolymer or of a mixture of halogen-containing polyolefins and/or halogen-containing copolymers or of a mixture of halogen-containing polyolefins and/or halogen-containing copolymers and halogen-free polyolefins and/or halogen-free copolymers and

(C) from 0.1 to 10% by weight of a free-radical generator or of a mixture of free-radical generators

and, after neutralizing at least 20# of the carboxyl groups present in the resultant polymerization product, dispersing the polymerization product in water, where the percentages for components (A), (B) and (C) are based on the total weight of (A), (B) and (C).

The plastics films according to the invention can be used to produce packaging containers, in particular for foods, and are distinguished by very good resistance to blocking.

The present invention therefore provides, in addition, a process to produce packaging containers using these plastics films, the packaging containers thus produced, and also the use of the aqueous coating compositions to coat plastics films and for application over printing ink. The mixture (A) used to prepare the acrylate dispersion used according to the invention comprises

(al) from ϊ to 50# by weight, based on the total weight of component (A), of acrylic acid or methacrylic acid or of a mixture of acrylic acid and methacrylic acid and

(a2) from 50 to 99# by weight, based on the total weight of component (A), of an ethylenically unsaturated monomer different from (al) or of a mixture of such ethylenically unsaturated monomers.

The composition of the mixture of (al) and (a2) is preferably selected in such a way that if the mixture of (al) and (a2) is polymerized alone the resultant polymer has a glass transition temperature of from 0 to 150°C, preferably from 10 to 80°C.

In addition, the composition of the mixture of (al) and (a2) is preferably selected in such a way that if the mixture of (al) and (a2) is polymerized alone the resultant polymer contains from 0.04 to 1.0 milliequivalents, preferably from 0.1 to 0.5 milliequivalents, of one or more of the following functional groups: -C00H, -OH, -NR₃, -CN, -C0NH₂, -CO-, -NHC0NH-, -0C0NH-, -0P0₃H₂, -0S0₃H, -R-O-R- (where R is an organic radical, preferably an alkyl or alkylene radical having from 1 to 6 carbon atoms) .

Since the glass transition temperatures of polymers prepared from ethylenically unsaturated monomers may be calculated from the equation

1/Tg = Σ Wn/Tgn Tg = glass transition temperature of the copolymer in °K n = proportion by weight of the nth monomer

Tgn = glass transition temperature of the homopolymer made from the nth monomer,

and ethylenically unsaturated monomers which contain -C00H, -OH, -NR₃, -CN, -C0NH₂, -CO-, -NHC0NH-, -0C0NH-, -0P0₃H₂, -0S0₃H or -R-O-R- (where R is an organic radical, preferably an alkyl or alkylene radical having from 1 to 6 carbon atoms) are commercially available, a person skilled in the art can readily select the composition of the mixture made from components (al) and (a2) in such a way that if the mixture of (al) and (a2) is polymerized alone the resultant polymer has the aboveentioned preferred Tg values and functional groups.

Taking into account the selection criteria described above, examples of compounds which may be used as component (a2) are: acrylates or methacrylates, in particular aliphatic acryl ates or methacrylates having up to 20 carbon atoms in the alcohol radical, such as methyl, ethyl, propyl , butyl , hexyl , ethyl hexyl , stearyl and 1 auryl acryl ate or the corresponding methacrylates, the corresponding esters of other ethylenically unsaturated acids having up to 6 carbon atoms in the molecule, such as ethacrylic acid and crotonic acid, acrylamidomethylpropanesulfonic acid, vinyl aromatic hydrocarbons, such as styrene, α-alkylstyrene and vinyltoluene, monomers containing amide groups, such as acrylamide, methacryl amide, N-methylolacryl amide and N-methylolmethacryl amide, and monomers containing nitrile groups, such as acrylonitrile and methacrylonitrile, or mixtures of the monomers mentioned. As component (B) , use is made of a halogen-containing polyolefin or of a' halogen-containing copolymer, or of a mixture of halogen-containing polyolefins and/or halogen-containing copolymers, or of a mixture of halogen-containing polyolefins and/or halogen-containing copolymers and halogen-free polyolefins and/or halogen-free copolymers.

Preference is given to the use of one or more fluorine-containing polyolefins as component (B). Particular preference is given to the use of polytetrafluoroethylene waxes as component (B).

Component (B) used may also be a mixture of

(bl) from 0 to 90# by weight, based on the total weight of component

(B), of a halogen-free polyolefin and/or of a halogen-free copolymer or of a mixture of more than one halogen-free polyolefin and/or halogen- free copolymer and

(b2) from 10 to 100# by weight, based on the total weight of component (B), of a halogen-containing polyolefin and/or of a halogen-containing copolymer or of a mixture of more than one halogen-containing polyolefin and/or halogen-containing copolymer.

The polyolefins and copolymers used according to the invention as component (B) preferably have an iodine number of up to 0.3 mg I₂/g, preferably from 0.005 to 0.05 mg I₂/g.

Preference is given to the use, as component (bl), of a homopolymer of propylene or of a copolymer of propylene and of at least one comonomer, such as ethylene, butylene or isoprene, or of a mixture of such polyolefins and/or copolymers.

Component (bl) used may also be a halogen-free copolymer of

(bbl) from 1 to 99* by weight, preferably from 50 to 90* by weight, based on the total weight of component (bl), of propylene,

(bb2) from 0 to 99* by weight, preferably from 10 to 50* by weight, based on the total weight of component (bl), of at least one olefin, other than isoprene, which is copolymerizable with (bbl) and contains from 5 to 20 carbon atoms per molecule, preferably from 6 to 8 carbon atoms per molecule, and

(bb3) from 0 to 50* by weight, preferably from 0 to 25* by weight, based on the total weight of component (bl), of ethylene and/or butylene

or a mixture of such copolymers.

As component (bb2), use is made of at least one olefin, other than isoprene, which is copolymerizable with (bbl) and contains from 5 to 20 carbon atoms per molecule, preferably from 6 to 8 carbon atoms per molecule. The olefin used as component (bb2) may be unbranched, branched, acyclic or cyclic. Examples of acyclic olefins are pentene, hexene, heptene, octene, nonene and decene. Examples of cyclic olefins are cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclononene, cyclodecene and norbornene. Olefins preferably used as component (bb2) are branched or unbranched acyclic olefins which contain, per molecule, from five to twenty carbon atoms, preferably from six to eight carbon atoms, and only one olefinically unsaturated double bond, preferably in^' the α position. Examples of such olefins are 1-pentene, 1- hexene, 1-heptene, 1-octene, 1-nonene and 1-decene. Particularly preferred components (bb2) are 1-hexene, 1- heptene and 1-octene.

The water-dilutable binders used according to the invention are prepared by free-radical polymerization of from 20 to 90* by weight, preferably from 54 to 85* by weight, of mixture (A) in the presence of from 9.9 to 79.9* by weight, preferably from 14 to 45* by weight, of component (B) and from 0.1 to 10* by weight, preferably from 1 to 7* by weight, of component (C), and, after neutralizing at least 20* of the carboxyl groups present in the resultant polymerization product, dispersing the polymerization product in water. The percentages for components (A), (B) and (C) are based on the total weight of (A), (B) and (C) .

The polymerization of mixture (A) in the presence of components (B) and (C) may be carried out in bulk, in aqueous emulsion or in an organic solvent, or in a mixture of organic solvents. The polymerization is preferably carried out in an organic solvent or in a mixture of organic solvents, in particular in apolar solvents having a boiling point in the range of from 120 to 200°C, preferably from 135 to 190°C, at polymerization temperatures of from 120 to 200°C, preferably from 130 to 160°C.

In principle, any known free-radical generator may be used as component (C). Preference is given to the use of free-radical generators based on per-compounds. In addition, preference is given to the use of free- radical generators which have a half-life time at the polymerization temperature of from 15 to 180 minutes. Examples of free-radical generators which may be used are: dialkyl peroxides, such as dicumyl peroxide and di -tert-butyl peroxide, peroxyesters , such as tert-butyl peroxybenzoate, tert-butyl peroxyoctanoate, tert-butyl peroxyacetate and tert-butyl peroxyisobutyrate, and diacyl peroxides, such as benzoyl peroxide and acetyl peroxide. Particular preference is given to the use of di-tert-butyl peroxide, tert-butyl perethyl hexanoate and tert-butyl peracetate as component (C) .

To neutralize the polymerization product, use is preferably made of organic amines, in particular of tertiary amines, such as dimethylethanol amine.

The coating compositions for the release coats according to the invention usually contain from 80 to 100* by weight of the acrylate copolymer solution or acrylate copolymer dispersion described above, based on the total weight of the coating composition. The solids content of the acrylate dispersions or solutions is generally from 10 to 30*. The coating compositions for the release coats may moreover usually also contain from 0 to 20* by weight, based on the total weight of the coating composition, of usual auxiliaries and additives.

Examples of suitable auxiliaries and additives are flow control agents, stabilizers, thickeners, defoamers, pigments, fillers and the like. The coating compositions may, for example, contain insoluble, finely dispersed inorganic substances, such as talc or silica, e.g. the commercial product Syloid 63 FP from Grace, and the like.

According to the invention, the aqueous coating compositions are used in particular for coating plastics films. Possible plastics films are preferably polyolefin films, for example polyethylene films and polypropylene films. These are particularly preferably of polypropylene, in particular of oriented polypropylene.

In the case of the plastics films referred to, one outer side of the plastics film is coated with a sealable coating and the opposite outer side of the plastics film is coated with the coating described above.

The coating described above and used according to the invention (release coat) here is usually applied to a printing ink layer. The release coat used according to the invention prevents the mutually superposed film layers from adhering to one another during use and if the plastics films are stored in the form of rolls for a relatively long period under normal storage conditions. It also serves to prevent migration of the printing ink.

In this respect, the plastics films under consideration may either be provided with a printing ink directly at the film producer, or else (as is more common) only the initial application of the sealable coating takes place at the film producer, and the printing ink (and therefore also the release coat) is applied only later by the user of the plastics film. In this second case, the film producer initially provides the plastics film with the sealable coating and with an outside coating prepared from an aqueous coating composition which, like the coating described above and used according to the invention (release coat), serves to prevent superposed film layers from adhering to one another during the storage and transport of the films on rolls. To this outside coating, the user of the film then applies firstly the printing ink and then the release coat. Wherever the coating of the plastics films with the printing ink takes place, the printed plastics films are provided, ^' after application of the printing ink, with the release coat described above and based on the dispersion/solution of the fluorine-modified acrylate.

The aqueous coating compositions referred to are moreover also suitable for the outer coating of unprinted plastics films, as used in industry, for example. In this case, the coating is applied directly, without prior or subsequent application of a printing ink, to the plastics film which may have been appropriately pretreated if desired.

To produce the plastics films according to the invention, the surface of the plastics films is usually pretreated, before applying the sealable coating or the aqueous coating composition for the outside coating, or the printing ink to the films, in order to ensure that the coating adheres firmly to the film. This is intended to prevent the coating from becoming peeled off or pulled off from the film.

This treatment is carried out by known methods, e.g. by chlorination of the plastics film, treatment with oxidants, such as chromic acid or hot air, or by steam treatment or flame treatment. A particularly preferred pretreatment used is high-voltage corona discharge.

After the pretreatment, the plastics films are generally precoated, in order to ensure adhesion of the coating to the substrate film. Suitable precoating agents or primers are known from the literature and encompass, for example, alky! titanates, and also primers based on epoxides, on mel amine- formaldehyde resins and on polyethyleneimines. The latter are particularly suitable for precoating plastics films. These polyethyleneimines may be applied to the, if desired pretreated, plastics films either from organic or else from aqueous solutions. The concentration of the polyethyleneimine in the aqueous or in the organic solution here can be, for example, 0.5* by weight. Suitable polyethyleneimine primers are described, for example, in DE-A-2440 112 and US-A-3,753,769.

The uncoated plastics films generally have a thickness of from 0.015 to 0.060 mm. The aqueous coating composition for the release coat is applied to the plastics film in a usual manner, for example by gravure coating, roller coating, dipping, spraying, or with the aid of gravure or flexoprinting or reverse-roll coating. The excess of aqueous solution may be removed by squeegee rollers or doctors. The coating composition for release coat is usually applied in an amount such that drying gives a smooth, uniformly distributed layer with a weight of from 1 to 5 g/m², preferably with a weight of from 2 to 3 g/m².

The coating formed on the plastics film by the aqueous coating composition, like the sealable coating layer, is dried separately or together with the sealable coating layer with hot air, radiant heat or by any other usual means.

The sealable coatings used to produce the plastics films are likewise known and are described, for example, in DE-A-4341815.

Use is made, in particular, of aqueous coating compositions for sealable coatings based on an acrylate dispersion. The sealable coatings are preferably sealed at a temperature of from 0 to 80°C, particularly preferably at least 30°C and very particularly preferably from 40 to

70°C.

The printing inks used to print the plastics films are likewise known.

The aqueous solution or dispersion, described above, of the acrylate copolymer is moreover also suitable as a binder in coating composition which are applied over a printing ink in processes to produce a multilayer coating on other substrates, e.g. wood.

The invention is described in more detail below using working examples, all data on parts and percentages being by weight unless expressly stated otherwise.

1.1. Preparation of acrylate dispersions 1 to 3

259 parts of a mixture of aromatic solvents having a boiling range of from 165 to 185°C (SHELLSOL^® A) and 300 parts of a commercially available polyethylene/polytetrafluoroethylene wax are weighed out in a polymerization vessel made from stainless steel, with stirrer, reflux condenser, a monomer feed and an initiator feed, and heated to a temperature of 130°C. The mixture is stirred at this temperature for 1 hour. A mixture of 72 parts of tert-butyl perethyl hexanoate and 133 parts of SHELLSOL^® A is then added dropwise to the homogeneous mixture at a constant rate within a period of 5 hours, the temperature of the reaction mixture being held constant. Thirty minutes after the addition of the initiator solution has begun, a mixture of the monomers given in Table 1 is added within a period of 4 hours. After the initiator feed has ended, polymerization is continued for 2 hours. 655 parts of SHELLSOL^® A are then used to adjust to a content of nonvolatile constituents of 60* by weight. This solution is then diluted with 873 parts of butyl acetate 98/100 to a content of nonvolatile constituents of 45* by weight. By applying reduced pressure, sufficient solvent is then distilled off to give a resin solution with a content of nonvolatile constituents of 40* by weight. The mixture is then heated to a temperature of 110°C. This solution is then mixed with 59.5 parts of dimethylethanol amine within a period of 30 in, and then stirred for 15 min. 1000 parts of deionized water are then added, with stirring, at 80°C. The organic solvents are finally distilled off from the resultant aqueous dispersion until a residual solvent content of less than 5* by weight has been achieved, adding a further 2998.0 parts of deionized water. The resultant aqueous dispersion has a content of nonvolatile fractions (1 h/130°C) of 21.5*, an acid number of 29.9 mg KOH/g and a pH value of 9.0.

Table 1: Monomer composition in parts and monomer composition in * by weight, based on the total weight of the monomers.

2. Preparation of a coating composition for the release coat and test results of the resultant coating

The coating composition for the release coat is prepared by diluting the acrylate dispersions with water to a solids content of 20*. A commercially available flexo-printing ink (commercial product Helioplastol HG A- from BASF Drucksyste e GmbH) is firstly applied with a wire-wound draw bar at a wet- film coating thickness of 6 micrometers to a commercially available oriented polypropylene 33MW247 from Mobil Plastics, Belgium which has been coated with an outside coating, and the ink is dried for 30 s at room temperature and then for 30 s at an air temperature of 60°C in a Helios laboratory heating cabinet. To the resultant printing ink layer, the coating composition for the release coat described above is applied with a wire-wound draw bar at a wet-film thickness of 12 micrometers, and dried for 30 s at room temperature and then for 30 s at an air temperature of 60°C in a Helios laboratory heating cabinet. The resistance to blocking of this coated film with respect to the packaging film coated with a cold-sealable coating according to DE-A-4341815 is determined by pressing together, for a period of 2 hours at 3.5 bar and 50°C, the film coated with the release coat and an OPP film made from oriented polypropylene 33MW247 from Mobil Plastics, Belgium, which has been coated with a cold-sealable coating according to DE-A-4341815. Test strips of widths of 25 mm are then cut from the test surface, and the resistance to blocking is then determined by peeling with the aid of an apparatus for measuring tension/elongation. The coated film shows adequate resistance to blocking. The seal strength is moreover not influenced unfavorably by the release coat.

Claims

1. A process for producing a multilayer coating on a substrate, in which a printing ink is initially applied, and an aqueous acryl ate-based coating composition is applied to the printing ink, characterized in that the coating composition applied to the printing ink comprises, as binder, an aqueous solution or dispersion of an acrylate copolymer, the solution or dispersion being obtainable by free- radical polymerization of

(A) from 20 to 90* by weight of a mixture comprising

(al) from 1 to 50* by weight, based on the total weight of component (A), of acrylic acid or methacrylic acid or of a mixture of acrylic acid and methacrylic acid and

(a2) from 50 to 99* by weight, based on the total weight of component (A), of an ethylenically unsaturated monomer different from (al) or of a mixture of such ethylenically unsaturated monomers,

in the presence of

(B) from 9.9 to 79.9* by weight of a halogen-containing polyolefin or of a halogen-containing copolymer or of a mixture of halogen-containing polyolefins and/or halogen- containing copolymers or of a mixture of halogen-containing polyolefins and/or halogen-containing copolymers and halogen-free polyolefins and/or halogen-free copolymers and (C) from 0.1 to 10* by weight of a free-radical generator or of. a mixture of free-radical generators

and, after neutralizing at least 20* of the carboxyl groups present in the resultant polymerization product, dispersing the polymerization product in water, where the percentages for components (A), (B) and (C) are based on the total weight of (A), (B) and (C).

2. The process according to claim 1, characterized in that the substrate is a plastics film, the side of the film opposite to the side with the printing ink being coated with a sealable coating.

3. The process according to claim 2, characterized in that an outside coating is applied on the side of the plastics film opposite to the sealable coating before the printing ink is applied.

4. The process according to claims 2 or 3, characterized in that the plastics film is coated with a primer before the sealable coating, if desired the outside coating, and the printing ink are applied.

5. A plastics film for producing packaging containers, one side of the film being- .coated with a sealable coating and the opposite side being coated with an aqueous acryl ate-based coating composition, characterized in that the coating composition applied to the side opposite to the sealable coating layer comprises, as binder, an aqueous solution or dispersion of an acrylate copolymer, the solution or dispersion being obtainable by free-radical polymerization of

(A) from 20 to 90* by weight of a mixture comprising

in the presence of

(B) from 9.9 to 79.9* by weight of a halogen-containing polyolefin or of a halogen-containing copolymer or of a mixture of halogen-containing polyolefins and/or halogen- containing copolymers or of a mixture of halogen-containing polyolefins and/or halogen-containing copolymers and halogen-free polyolefins and/or halogen-free copolymers and

(C) from 0.1 to 10* by weight of a free-radical generator or of a mixture of free-radical generators

6. The plastics film according to claim 5, characterized in that it has been coated with a primer before the sealable coating and the acryl ate-based coating have been applied.

7. A plastics film for producing packaging containers, one side of the film being coated with a sealable coating and the opposite side of the film being coated with a multilayer coating obtainable by the process according to any of claims 2 to 4.

8. The plastics film according to any of claims 5 to 7, characterized in that it is obtainable by using component (A) in an amount from 54 to 85* by weight and/or component (B) in an amount from 14 to 45* by weight and/or component (C) in an amount from 1 to 7* by weight, based in each case on the total weight of (A), (B) and (C).

9. The plastics film according to any of claims 5 to 8, characterized in that it is obtainable by using component (al) in an amount from 2 to 15* by weight and component (a2) in an amount from 85 to 98* by weight, based in each case on the total weight of component (A).

10. The plastics film according to any of claims 5 to 9, characterized in that it is obtainable by using, as component (B), a mixture comprising

(bl) from 0 to 90* by weight, based on the total weight of component (B) , of a hal ogen- free polyolefin and/or of a halogen-free copolymer or of a mixture of more than one halogen-free polyolefin and/or halogen-free copolymer and

(b2) from 10 to 100* by weight, based on the total weight of component (B), of a halogen-containing polyolefin and/or of a halogen-containing copolymer or of a mixture of more than one halogen-containing polyolefin and/or halogen-containing copolymer .

11. The plastics film according to any of claims 5 to 10, characterized in that the sealable coating is prepared from an aqueous coating composition based on an acrylate dispersion.

12. A process for producing packaging containers from plastics film, characterized by using the plastics film according to any of claims 5 to 11.

13. The process according to claim 12 characterized in that the sealable coatings are sealed at a temperature of from 0 to 80°C, preferably at least 30°C and particularly preferably from 40 to 70°C.

14. A packaging container obtainable by the process according to claims 12 or 13.

15. The use of an aqueous solution or dispersion of an acrylate copolymer, the solution or dispersion being obtainable by free- radical polymerization of (A) from 20 to 90* by weight of a mixture comprising

in the presence of

(C) from 0.1 to 10* by weight of a free-radical generator or of a mixture of free- adical generators

and, after neutralizing at least 20* of the carboxyl groups present in the resultant polymerization product, dispersing the polymerization product in water, where the percentages for components (A), (B) and (C) are based on the total weight of (A), (B) and (C), as binder in an aqueous coating composition for coating plastics films which are used to produce packaging containers, in particular to produce food packaging containers.