WO1998037129A1

WO1998037129A1 - Plastics film, its use in processes for producing 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: WO1998037129A1
Application number: PCT/EP1998/000974
Authority: WO
Inventors: Harald Borgholte; Christopher Hilger; Horst HINTZE-BRÜNING; Peter Eric Van Rijn
Original assignee: Ppg Industries Ohio, Inc.
Priority date: 1997-02-22
Filing date: 1998-02-20
Publication date: 1998-08-27
Also published as: DE19707186A1; AU6722598A

Abstract

The present invention relates to a plastics film for producing packaging containers, one outer side of the film being coated with a sealable coating and the opposite outer side being coated with an outside coating composition, wherein the outside coating composition contains 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-free polyolefin and (C) from 0.1 to 10 % by weight of at least one free-radical generator and dispersing in water the polymerization product obtained, where the percentages by weight for components (A), (B) and (C) are based on the total weight of (A), (B) and (C).

Description

PLASTICS FILM, ITS USE IN PROCESSES FOR PRODUCING 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 outer side of the film being coated with a sealable coating and the opposite outer side of the film being coated with an aqueous acrylate-based composition for outside coating ("outside coating composition") .

The present invention moreover relates to a process for producing packaging containers using these plastics films, to the packaging containers thus produced, and to the use of aqueous coating compositions to coat plastics films for producing packaging containers.

Plastics films which are intended to be used, for example, for packaging 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, the plastics films are provided with adhesive coatings.

The adhesive coatings in particular cases are either hot-sealable coatings, which can be sealed at elevated temperatures, or cold-sealable coatings, which are sealed at temperatures of from about 0 to 40°C.

Cold-sealable coatings and their properties are described, for example, in L. Placzek, Coating, 18 (4), pages 94 - 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. for packaging of chocolates and ice cream.

Seal able 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 prolonged period under normal storage conditions in the form of rolls, show a tendency to stick to the mutually superposed layers of film.

Cold-sealable coatings therefore require the application of a protective layer on the other side of the film. The outside coating compositions used for this purpose usually 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 coatings which are known and usually used, however, have the disadvantage that the wax used in the outside coating can be transferred to some extent onto the seal able coating, resulting in an adverse effect on the sealing properties. The mixtures of the wax and the acrylate copolymer usually used in these outside coatings moreover have unsatisfactory shelf life. Finally, DE-A-4412655 and the as yet unpublished German Patent Application P 19538147.5 disclose aqueous coating compositions based on polyacrylate resins which have been prepared by polymerizing ethylenically unsaturated monomers in the presence of halogen-free polyolefins. These coatings are used to coat plastics. However, the texts do not describe the use of these coatings for coating plastics films which are used for producing packaging containers.

The object on which the present invention is based is therefore to provide plastics films suitable for producing packaging containers and having 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 printable on the side facing away from the sealable coating. They should, furthermore, be odorless, so as to be suitable also for food packaging. They should moreover have very good optical properties. In addition, the plastics films should, if they are used directly to produce packaging containers, be sealable under the conditions usually used. Finally, the aqueous outside coatings used to coat the plastics films should have very long shelf lives.

Surprisingly, this object is achieved by means of the plastics films of the type described at the outset, wherein the outside coating contains, as binder, an aqueous acrylate dispersion, which is obtainable by free- radical polymerization of

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

(al) from 1 to SOX by weight, based on the total weight of component (A), of acrylic acid, methacrylic acid or 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-free polyolefin or of a halogen-free copolymer or of a mixture of 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 dispersing in water the polymerization product obtained, after neutralization of at least 20# of the carboxyl groups present in the polymerization product, where the percentages by weight for components (A), (B) and (C) are based on the total weight of (A), (B) and (C) .

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

The present invention therefore provides, in addition, a process for producing packaging containers using these plastics films, the packaging containers thus produced, and also the use of aqueous coating compositions to coat plastics films for producing packaging containers.

The mixture (A) used for preparing the acrylate dispersion used according to the invention comprises (al) from 1 to 50% by weight, based on the total weight of component (A), of acrylic acid, methacrylic acid or 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 0.14 to 7 milliequivalents of one or more of the following functional groups: -C00H, -OH, -NR_3> -CN, -C0NH₂, -CO-, -NHC0NH-, -0C0NH-, -0P0₃H₂, -0S0₃H and -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 temperature of polymers prepared from ethylenically unsaturated monomers may be calculated from the equation

1/Tg = Σ W_n/Tg_n

Tg = glass transition temperature of the copolymer in °K Wn = 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, -0SO₃H 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, the person skilled in the art can readily select the composition of the mixture of components (al) and (a2) in such a way that if the mixture of (al) and (a2) is polymerized alone the resulting polymer has the parameters mentioned.

Taking into account the selection criteria described above, examples of compounds which may be used as component (a2) are: acrylates or methacryl ates, in particular aliphatic acrylates or methacryl ates having up to 20 carbon atoms in the alcohol radical, such as methyl, ethyl, propyl, butyl, hexyl, ethyl hexyl, octyl, decyl and dodecyl acrylate or methacrylate, 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, vinylaromatic hydrocarbons, such as styrene, α-alkylstyrene and vinyltoluene, monomers containing amide groups, such as acrylamide, methacrylamide, N-methylolacrylamide and N- ethylolmethacrylamide, 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-free polyolefin or a halogen- free copolymer or a mixture of halogen-free polyolefins and/or halogen- free copolymers. A homopolymer of propylene or a copolymer of propylene and at least one coonomer, such as ethylene, butylene or isoprene, or a mixture of such polyolefins and/or copolymers is preferably used as component (B) . The polyolefins and copolymers used according to the invention as component (B) preferably have a weight-average molecular weight of from 1000 to 100,000, preferably from 3000 to 55,000 (determined by gel permeation chromatography using a polypropylene standard) and/or an iodine number of up to 0.3 mg I₂/g, preferably from 0.005 to 0.05 mg I₂/g, and they may have been subjected to a grafting reaction with maleic anhydride.

It is also possible to use, as component (B), a halogen-free copolymer of

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

(b2) from 0 to 99% by weight, preferably from 10 to 50% by weight, based on the total weight of component (B), of at least one olefin, other than isoprene, copolymerizable with (bl) and containing, per molecule, from 5 to 20 carbon atoms, preferably from 6 to 8 carbon atoms, and

(b3) from 0 to 50% by weight, preferably from 0 to 25% by weight, based on the total weight of component (B), of ethylene and/or butylene

or a mixture of such copolymers.

As component (b2), use is made of at least one olefin, other than isoprene, which is copolymerizable with (bl) and contains, per molecule, from five to twenty carbon atoms, preferably from six to eight carbon atoms. The olefin used as component (b2) 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, cyc oheptene, cyclooctene, cyclononene, cyclodecene and norbornene. Use is preferably made, as component (b2), of branched or unbranched acyclic olefins which have from five to twenty carbon atoms, preferably from six to eight carbon atoms, per molecule, and only one olefinically unsaturated double bond, preferably in the exposition. Examples of such olefins are 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene and 1-decene. Particular preference is given to the use of 1-hexene, 1-heptene and 1-octene as component (b2).

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 dispersing in water the polymerization product obtained, after neutralization of at least 20% of the carboxyl groups present in the polymerization product. 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.

Compounds used as component (C) may in principle be any known free- radical generators. 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, at the polymerization temperature, have a half-life time of from 15 to 180 minutes. Examples of free-radical generators which may be used are: dial yl 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, and also azo compounds, such as azobis(isobutyronitrile). Compounds particularly preferably used as component (C) are di-tert-butyl peroxide, tert-butyl perethylhexanoate and tert-butyl peracetate.

Polymerization regulators, in particular those based on ercaptans, may moreover be used in these systems. The polymerization regulators are usually used in an amount of from 0.1 to 5% by weight, based on the total weight of the monomers used.

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

The resultant acrylate dispersions are used according to the invention as binders in aqueous coating compositions for coating plastics films. These aqueous coating compositions usually contain from 10 to 40% by weight, preferably from 15 to 25% by weight, of the acrylate copolymer described above (used as aqueous dispersion), based on solid resin and on the total weight of the aqueous coating composition.

These aqueous coating compositions moreover usually also contain from 40 to 90% by weight of water and from 0 to 20% by weight, based in each case on the total weight of the aqueous coating composition, of usual auxiliaries and additives. Examples of suitable auxiliaries and additives are hydrophobicizers, flow control agents, stabilizers, thickeners, defoamers and additives which have a favorable effect on slip performance. The aqueous 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.

These aqueous coating compositions are used according to the invention for coating plastics films. In the case of the plastics films referred to, one outer side of the plastics film is coated with a seal able coating and the opposite outer side of the plastics film is coated with the aqueous coating composition described above. The resulting coating prevents the mutually superposed layers of film 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. The aqueous outside coating is also intended to allow the application of a printing ink to this outside coating layer.

Before application of the aqueous coating composition and of the seal able coating to the plastics films, the surface of the films is generally pretreated 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.

The plastics films are generally precoated after the pretreatment, in order to secure adhesion of the coating to the substrate film. Suitable precoating agents or primers are known from the literature and encompass, for example, alkyl 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 solution. The concentration of the polyethyleneimine in the aqueous or in the organic solution here is, 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 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 flexo printing or reverse-roll coating. The excess of aqueous solution may be removed by squeegee rollers or doctors. The coating compositions are usually applied in an amount which, on drying, gives a smooth, uniformly distributed layer with a weight of from 0.5 to 5 g/m², preferably with a weight of from 1 to 2 g/m².

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

The seal able coatings used for producing the plastics films are likewise known and are described, for example, in DE-A-4341815.

Use is made, in particular, of aqueous compositions for seal able coatings based on an acrylate dispersion. The seal able 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 for subsequent printing of the plastics films are likewise known and therefore do not require more detailed description. The printed plastics films are usually then provided with a release coat. These release coats used are likewise known and therefore do not require more detailed description.

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

1.1. Preparation of acrylate dispersions 1 to 3

The amounts given in Table 1 of a mixture of aromatic solvents having a boiling range of from 165 to 185°C (SHELLSOL® A) and the wax 1 or 2 given in Table 1 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 the temperature given in Table 1. The mixture is stirred for 1 hour at this temperature. A mixture of the parts given in Table 1 of initiator and solvent is then added dropwise to the homogeneous mixture at a constant rate within the time given, the temperature of the reaction mixture being held constant. 15 minutes after the addition of the initiator solution has begun, a mixture of the monomers given in Table 1 is added within the time stated. After the initiator feed has ended, polymerization is continued for the time stated in each case. Reduced pressure is then applied so that a sufficient amount of solvent is distilled off to give a resin solution with a content of non-volatile constituents of 95% by weight. This solution is then diluted with the amount stated in each case of butyl acetate 98/100, or in Example 1 with the amount given in Table 1 of Shellsol® A, to a content of non-volatile constituents of 60% by weight, and in Example 1 then with the amount stated in each case of butyl acetate 98/100 to a content of non-volatile constituents of 40% by weight, and heated to the temperature stated in each case. This solution is then mixed with dimethylethanolamine and stirred for the time stated. Deionized water is then added, with stirring, at 80°C. Finally, the organic solvents are distilled off from the resultant aqueous dispersion until a residual solvent content of less than 5% by weight has been achieved. The resultant aqueous dispersion has the content of non- volatile fractions (1 h/130°C), the acid number, and the pH value which are given in each case.

Table 1: Preparation of acrylate dispersions 1 to 3

Key to Table 1:

SV IC: amount in parts of Shell sol® A added in the initial charge

Wax 1 IC: amount in parts of a commercially available polypropylene wax added in the initial charge, the wax having a high polyethylene fraction and a weight-average molecular weight of 55,000, a melting point of 130°C and a viscosity at 180°C of 9,500 mPa.s; bracket value: amount of wax based on total amount of monomers

Wax 2 IC: amount in parts of a commercially available isotactic polypropylene wax added in the initial charge, the wax having a weight- average molecular weight of about 20,000 (GPC against polypropylene standard), a melting point of 155°C and a viscosity at 180°C of 0.2 Pa.s; bracket value: amount of wax based on total amount of monomers

SV init: amount in parts of Shell sol® A added to initiator feed

DTBP: amount in parts of di -tert-butyl peroxide (amount in %, based on total amount of monomers)

TBPEH: amount in parts of tert-butyl perethyl hexanoate (amount in %, based on total amount of monomers)

T IC: temperature to which the initial charge is heated

T react: reaction temperature

Duration mon: duration in hours of the monomer feed

Duration init: duration in hours of the initiator feed Duration cont: duration in hours of the continued polymerization

Duration DMEA: duration of stirring after dimethylethanolamine addition

MA: amount in parts of methyl acrylate added

MMA: amount in parts of methyl methacrylate added

MAA: amount in parts of methacrylic acid added

EHA: amount in parts of ethylhexyl acrylate added

CHMA: amount in parts of cyclohexyl methacrylate added

BMA: amount in parts of butyl methacrylate added

AA: amount in parts of acrylic acid added

Xylene: amount in parts of xylene added

BA: amount in parts of butyl acetate 98/100 added

Shell sol® A: amount in parts of Shellsol® A added

DMEA: amount in parts of dimethylethanolamine added

Water: amount in parts of water added

SC (%): solids content in % at 60 min, 130°C

AN (mg KOH/g) : acid number in mg KOH/g pH: pH value

Shelf life at 40°C: shelf life of the dispersion when stored at 40°C

2. Preparation of aqueous coating compositions 1 to 3

Using acrylate dispersions 1 to 3, aqueous coating compositions 1 to 3 were prepared by adjusting with water to a solids content of 20%.

3. Application of aqueous coating compositions 1 to 3 and test results from the resultant coatings

Each of coating compositions 1 to 3 is applied with a wire-wound draw bar to oriented polypropylene from Mobil Plastics, Belgium, provided with a polyethylenei ine-based primer. The coating weight is 1.5 ± 0.5 g/m². The film is dried for 1 minute at an air temperature of 120°C in a Heraeus laboratory heating cabinet.

The resistance to blocking of these coated films with respect to the packaging film coated with a seal able coating (resulting from application of an aqueous coating composition) is determined by pressing together, under the conditions given in Table 2, the film coated with coating 1 to 3 and an OPP film made from oriented polypropylene 33MW247 from Mobil Plastics, Belgium, which has been coated with a seal able coating according to DE-A-4341185, based on an acrylate copolymer containing acrylonitrile groups. Test strips of width 25 mm are then cut from the test surface, and resistance to blocking is then determined by peeling with the aid of an apparatus for measuring tension/ elongation. The results of this measurement are given in Table 2. Table 2: Results of the blocking resistance test (in g/25 mm)

The films coated with aqueous coating compositions 1 to 3 are moreover printable with the printing inks usually used.

Claims

1. A plastics film for producing packaging containers, one outer side of the film being coated with a sealable coating and the opposite outer side being coated with an aqueous acrylate-based outside coating composition, characterized in that the outside coating composition comprises, as binder, an aqueous acrylate dispersion which is 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, methacrylic acid or 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 - free polyolefin or of a halogen - free copolymer or of a mixture of 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 dispersing in water the polymerization product obtained, after neutralization of at least 20% of the carboxyl groups present in the polymerization product, where the percentages by weight for components (A), (B) and (C) are based on the total weight of (A), (B) and (C).

2. The plastics film as claimed in claim 1, characterized in that it is obtainable by using component (A) in an amount of from 54 to 85% by weight and/or component (B) in an amount of from 14 to 45% by weight and/or component (C) in an amount of from 1 to 7% by weight, based in each case on the total weight of components (A), (B) and (C).

3. The plastics film as claimed in claim 1 or 2, characterized in that it is obtainable by using component (al) in an amount of from 2 to 15% by weight and component (a2) in an amount of from 85 to 98% by weight, based in each case on the total weight of component (A).

4. The plastics film as claimed in any one of claims 1 to 3, characterized in that it is obtainable by using, as component (B), one or more polyolefin waxes having a weight-average molecular weight of from 1000 to 100,000, preferably from 3000 to 55,000, and/or an iodine number of up to 0.3 mg of I₂/g, preferably from 0.005 to 0.05 mg of

Vg.

5. The pl astics film as cl aimed in any one of cl aims 1 to 4, characterized in that it is obtainable by using, as component (B) , a halogen-free copolymer of (bl) from 1 to 99% by weight, based on the total weight of component (B) , of propylene,

(b2) from 0 to 99% by weight, based on the total weight of component (B), of at least one olefin, other than isoprene, copolymerizable with (bl) and containing, per molecule, from five to twenty carbon atoms, preferably from six to eight carbon atoms and

(b3) from 0 to 50% by weight, based on the total weight of component (B), of ethylene and/or butylene.

6. The plastics film as claimed in any of claims 1 to 5, characterized in that the sealable coating is prepared from a coating composition based on an acrylate dispersion.

7. The plastics film as claimed in any of claims 1 to 6, characterized in that the plastic film has been coated with a primer before application of the sealable coating and the aqueous outside coating composition.

8. The plastics film as claimed in any of claims 1 to 7, characterized in that a printing ink has been applied to the outside coating resulting from application of the aqueous outside coating composition and a release coat has been applied over the printing ink.

9. A process for producing packaging containers from plastics films, characterized by using the plastics film as claimed in any of claims 1 to 8.

10. The process as claimed in claim 9, 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.

11. A packaging container obtainable by the process as claimed in claims 9 or 10.

12. The use of an aqueous acrylate dispersion which is 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-free polyolefin or of a halogen -free copolymer or of a mixture of 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 dispersing in water the polymerization product obtained, after neutralization of at least 20% of the carboxyl groups present in the polymerization product, where the percentages by weight for components (A), (B) and (C) are based on the total weight of (A), (B) and (C), as a binder in an aqueous coating composition for coating plastics films which are used for producing packaging containers, in particular for producing food packaging containers.