WO2004101279A1

WO2004101279A1 - Packaging material consisting of an at least double-layered composite material for producing containers for packing liquids

Info

Publication number: WO2004101279A1
Application number: PCT/EP2004/004820
Authority: WO
Inventors: Simon Champ; Roland Ettl
Original assignee: Basf Aktiengesellschaft
Priority date: 2003-05-16
Filing date: 2004-05-06
Publication date: 2004-11-25
Also published as: BRPI0410262A; US20070010386A1; EP1626866A1; CA2525626A1; JP2007500628A

Abstract

The invention relates to a packaging material consisting of an at least double-layered composite comprising paper or cardboard which is glued into the mass by means of a polymer gluing agent and at least one film which is impermeable to water, for producing containers for packing liquids. The invention also relates to the use of paper products for producing containers for packing liquids, especially drinks, said paper products being respectively obtained by (i) gluing a paper material consisting of an aqueous suspension of cellulose fibres into the mass by means of at least one polymer gluing agent or a polymer gluing agent and an aqueous dispersion of an alkyl ketene dimer or the mixtures thereof in the presence of a retention agent and optionally a water-soluble aluminium compound and optionally at least one cationic polymer, (ii) the paper material is drained on the wire of a paper machine, (iii) the paper product is dried, and (iv) the paper product is laminated on one or both sides with a plastic or metal film.

Description

Packaging material from an at least two-layer composite material for the production of containers for packaging liquids

description

The invention relates to a packaging material made of an at least two-layer composite of glued paper or glued cardboard and at least one water-impermeable film for the packaging of liquids and the use of paper products which are glued in bulk and which are coated on one or both sides with a film made of plastic or Metal are laminated for the production of containers for the packaging of liquids, in particular beverages.

EP-B-0 292 975 discloses the use of an emulsion of an alkyl ketene dimer in combination with a cationic resin size and an insolubilizing agent such as alum for the production of cardboard for the packaging of liquids. The cardboard is produced by adding sizing agents and alum to an aqueous slurry of cellulose fibers and dewatering the paper stock on a sieve.

EP-A-1 091 043 discloses a process for producing a coated packaging carton, in which an aqueous slurry of cellulose fibers is glued in bulk with an aqueous dispersion of a resin glue, a synthetic sizing agent such as alkyl ketene dimer and at least one aluminum compound, and the aqueous slurry drained on a sieve. The aqueous dispersions of bulk sizing agents may optionally contain a dispersing agent, e.g. cationic starch, casein, cellulose derivatives, polyvinyl alcohols, polyacrylamides or polyethyleneimines. The cardboard is usually coated after the sizing.

Paper products for packaging foodstuffs laminated on both sides with a liquid-impermeable layer are known from WO-A-02/090206. The paper products are glued in bulk with aqueous dispersions of alkyl ketene dimers. The amount of alkyl ketene dimers is at least 0.25% by weight, preferably 0.25-0.4% by weight, based on the weight of the dry paper products.

Further multilayer packaging materials, the base layer of which consists of paper or cardboard, are described, for example, in WO-A-97/02140, WO-A-97/02181 and WO-A-98/18680.

It is also known from the prior art to use sizing agent mixtures from aqueous dispersions of alkyl ketene dimers and polymer sizing agents for mass to use gluing of paper and cardboard, cf. DE-A-32 35 529, WO-A-94/05855 and WO-A-96/31650.

A process for the production of cardboard for packaging liquids is known from the older DE application 10237913.0. In this process, the cardboard is produced by mass sizing an aqueous slurry of cellulose fibers with at least one mass sizing agent in the presence of at least one retention agent and at least one cationic polymer and optionally a water-soluble aluminum compound and dewatering the paper stock on a sieve. Sizing agents are alkyl ketene dimers, alkyl and alkenyl succinic anhydrides, alkyl isocyanates, combinations of resin glue and alum and combinations of reaction products of resin glue with carboxylic acid anhydrides and alum.

The object of the present invention is to provide further packaging materials based on paper products, the packaging in particular being to have improved edge penetration and improved adhesion of the laminates to paper or cardboard.

The object is achieved according to the invention with a packaging material made of an at least two-layer composite of sized paper or sized cardboard and at least one water-impermeable film for the production of containers for the packaging of liquids if the paper or the box is sized in the mass with a polymer sizing agent.

The invention also relates to the use of paper products which are each obtainable from

Bulk sizing of a paper stock from an aqueous slurry of cellulose fibers with at least one polymer sizing agent as bulk sizing agent or with a polymer sizing agent and an aqueous dispersion of an alkyl ketene dimer or mixtures thereof in the presence of a retention aid and optionally a water-soluble aluminum compound and optionally at least one cationic polymer, dewatering the paper stock the sieve of a paper machine, drying the paper product and laminating the paper product on one or both sides with a film made of a plastic or metal, for the production of containers for the packaging of liquids, in particular beverages. For the production of glued paper or glued cardboard all cellulose fibers commonly used in the paper industry can be used, for example fibers made from wood pulp and all annual plants. Wood pulp is understood to mean, for example, wood pulp, thermomechanical pulp (TMP), chemothermomechanical pulp (CTMP), pressure grinding, semi-pulp, high-yield pulp, refiner mechanical pulp (RMP) and waste paper. Also suitable are pulps that can be used in bleached or unbleached form. Examples of these are sulfate, sulfite and sodium pulps. Unbleached pulps, which are also referred to as unbleached kraft pulp, are preferably used. The fibrous materials can be used alone or as a mixture with one another.

In the case of mass sizing of paper or cardboard, sizing takes place during the manufacturing process of these materials by adding a so-called mass sizing agent to the paper stock and dewatering it on the sieve of a paper machine with sheet formation. According to the invention, a polymer sizing agent made from synthetic polymers is used as the mass sizing agent. The polymer sizing agents known from JP-A-58/115 196 are aqueous polymer dispersions which are a sizing agent for paper and at the same time increase the strength of paper. These dispersions are prepared by polymerizing, for example, styrene and alkyl acrylates in the presence of starch and radical-forming polymerization initiators in an aqueous medium. The starch used in each case is broken down or broken down before the polymerization, so that it is soluble in water. The polymers of these dispersions are graft polymers of styrene and alkyl acrylates on starch or modified starch.

Further polymer sizing agents are known from EP-B-0257412 and EP-B-0267770. They are obtained by copolymerizing acrylonitrile and / or methacrylonitrile and at least one acrylic acid ester of a monohydric, saturated C ₃ to C ₈ alcohol in the manner of an emulsion polymerization in an aqueous solution which contains a degraded starch, in the presence of free radical initiators, preferably hydrogen peroxide or redox initiators. The degraded starches have viscosities / 7, from 0.04 to 0.50 dl / g. Such starches are obtained, for example, in the case of oxidative, thermal, acidolytic or enzymatic degradation of a native, cationically or anionically modified starch. Native starches from potatoes, wheat, corn are advantageous. Rice or tapioca used. An enzymatically degraded potato starch is preferred. The degraded starches act as emulsifiers in the copolymerization of, for example, styrene and n-butyl acrylate in an aqueous medium. The aqueous solution in which the copolymerization is carried out contains, for example, 1 to 25% by weight of at least one degraded starch. In 100 parts by weight of such a solution is polymerized, for example, 10 to 150, preferably 40 to 100 parts by weight of the above monomers. Instead of acrylonitrile and / or methacrylonitrile, styrene can also be used in the copolymerization, cf. WO-A-94 / 05,855th Aqueous dispersions of copolymers with an average particle diameter of, for example, 50 to 500 nm, preferably 100 to 300 nm, are obtained. These polymer dispersions are presumably graft polymers of the monomers used in each case on degraded starch.

Further polymer sizing agents based on copolymers of styrene and C ₃ -C ₈ -alkyl (meth) acrylates are known from WO 02/14393. They are prepared by copolymerizing the monomers mentioned in an aqueous medium in the presence of degraded starch and radical-forming polymerization initiators using a two-stage process.

Aqueous polymer dispersions which can be prepared in the presence of synthetic polymeric protective colloids are also suitable as polymer sizing agents. They can be obtained, for example, by copolymerizing 2 to 32 parts of a mixture of

(a) styrene, acrylonitrile and / or methacrylonitrile,

(b) acrylic acid and / or methacrylic acid esters of d to C ₁₈ alcohols and / or vinyl esters of saturated C ₂ to C ₄ carboxylic acids and optionally

(c) other monoethylenically unsaturated copolymerizable monomers

in aqueous solution in the presence of 1 part by weight of a solution copolymer

(1) di-Ci to C-alkylamino-C ₂ to C ₄ -alkyl (meth) acrylates, which can optionally be protonated or quaternized,

(2) nonionic, hydrophobic, ethylenically unsaturated monomers, in the case of these monomers, if they are polymerized on their own, form hydrophobic polymers and, if appropriate,

(3) monoethylenically unsaturated C ₃ to C ₅ carboxylic acids or their anhydrides, the molar ratio of (1): (2): (3) = 1: 2.5 to 10: 0 to 1.5 being co- polymerized. A solution copolymer is first prepared by copolymerizing the monomers of groups (1) and (2) and, if appropriate, (3) in a water-miscible organic solvent. Suitable solvents are, for example, C to C ₃ carboxylic acids, such as formic acid, acetic acid and propionic acid, or C to C alcohols, such as methanol, ethanol, n-propanol or isopropanol, and ketones such as acetone. The group (1) monomers used are preferably dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylate and dimethylaminopropyl acrylate. The monomers of group (1) are preferably used in protonated or quaternized form. Suitable quaternizing agents are, for example, methyl chloride, dimethyl sulfate or benzyl chloride.

The group (2) monomers used are nonionic, hydrophobic, ethylenically unsaturated compounds which, when polymerized on their own, form hydrophobic polymers. These include, for example, styrene, methylstyrene, C to Cis-alkyl esters of acrylic acid or methacrylic acid, for example methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, tert-butyl acrylate and isobutyl acrylate as well as isobutyl methacrylate, n-butyl methacrylate and tert. butyl methacrylate. Acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate and vinyl butyrate are also suitable. Mixtures of the group 2 monomers can also be used in the copolymerization, for example mixtures of styrene and isobutyl acrylate. The solution copolymers used as emulsifiers may optionally also contain monomers of group (3) in copolymerized form, for example monoethylenically unsaturated C ₃ -C ₅ -carboxylic acids or their anhydrides, for example acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride or itaconic anhydride. The molar ratio of (1): (2): (3) is 1: 2.5 to 10: 0 to 1.5. The copolymer solutions thus obtained are diluted with water and, in this form, serve as a protective colloid for the polymerization of the above-mentioned monomer mixtures of components (a) and (b) and, if appropriate, (c). Monomers of group (a) are styrene, acrylonitrile, methacrylonitrile or mixtures of styrene and acrylonitrile or of styrene and methacrylonitrile. The monomers of group (b) used are acrylic acid and / or methacrylic acid esters of d to C ₁₈ alcohols and / or vinyl esters of saturated C ₂ to C ₄ carboxylic acids. This group of monomers corresponds to the monomers of group (2), which has already been described above. Preferably used as the monomer of group (b) are acrylic acid butyl ester and methacrylic acid butyl ester, for example acrylic acid isobutyl acrylate, acrylic acid n-butyl acrylate and methacrylic acid isobutyl acrylate. Monomers of group (c) are, for example, C ₃ -C ₅ -monoethylenically unsaturated carboxylic acids, acrylamido-methylpropanesulfonic acid, sodium vinyl sulfonate, vinyl imidazole, N-vinyl formamide, acrylic amide, methacrylamide and N-vinyl imidazoline. 1 to 32 parts by weight of a monomer mixture of the components are used per 1 part by weight of the copolymer. ten (a) to (c). The monomers of components (a) and (b) can be copolymerized in any ratio, for example in the molar ratio 0.1: 1 to 1: 0.1.

If necessary, the monomers of group (c) are used to modify the properties of the copolymers.

Sizing agents of this type are described, for example, in EP-B-0 051 144, EP-B-0 058313 and EP-B-0 150 003.

Aqueous polymer dispersions which are obtained by copolymerizing

20 to 65% by weight of styrene, acrylonitrile and / or methacrylonitrile,

80 to 35% by weight of acrylic acid and / or methacrylic acid esters of monovalent saturated C ₃ to C ₈ alcohols and

0 to 20% by weight of other monoethylenically unsaturated copolymerizable monomers such as acrylamide, methacrylamide, vinylformamide, acrylic acid, methacrylic acid, maleic acid, itaconic acid, 2-acrylamido-2-methylpropanesulfonic acid or basic monomers such as dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminopropyl acrylate or dimethylaminoethyl acrylate basic monomers are mostly used as hydrochlorides or in a form quaternized with methyl chloride, dimeethyl sulfate or benzyl chloride,

are available as protective colloid in the presence of free radical initiators in the manner of an emulsion polymerization in an aqueous solution of a degraded starch.

Furthermore, aqueous polymer dispersions which are obtained by copolymerizing

60 to 90% by weight of styrene and / or methylstyrene,

10 to 40 wt .-% butadiene-1, 3 and / or isoprene and

0 to 20% by weight of other monoethylenically unsaturated copolymerizable monomers such as acrylic acid, methacrylic acid, itaconic acid, acrylamide, methacrylamide or N-vinylpyrrolidone,

are available as protective colloid in the presence of free radical initiators in the manner of an emulsion polymerization in an aqueous solution of a degraded starch. The polymer sizing agents are preferably cationic or anionic. The charge of the aqueous dispersions is based either on the type of comonomers polymerized into the copolymers, for example when using basic monomers Polymer sizing agent dispersion cationic, while it becomes anionic by copolymerizing, for example, acrylic acid or its salts, or on the charge of the protective colloid used in each case. For example, the use of cationic starch as an emulsifier leads to cationically adjusted polymer size dispersions.

For mass sizing of paper or cardboard, for example, 0.1 to 2.0, preferably 0.2 to 0.75% by weight of polymer sizing agent (i.e. 100% polymer), based on dry paper product, is used.

The bulk sizing of paper and cardboard can additionally in the presence of aqueous dispersions of reactive sizing agents such as alkyl ketene dimers, C ₅ - to C ^ alkyl and / or C ₅ - to C22-alkenyl succinic anhydrides, chloroformic acid esters and C ₁₂ - to C ₃₆ - alkyl isocyanates and in In the presence of combinations of resin glue and alum or combinations of reaction products of resin glue with carboxylic acid anhydrides and alum. Instead of alum or in combination with alum, other aluminum-containing compounds such as polyaluminium chlorides or the polyaluminium compounds known from EP-B-1 091 043 can be used.

Of the reactive sizing agents, preference is given to using C ₁₂ to C ₂₂ alkyl ketene dimers, for example stearyl diketene, lauryl diketene, palmityldiketene, oleyl diketene, behenyl diketene or mixtures thereof.

Suitable succinic anhydrides are e.g. Decenyl succinic anhydride, octenyl succinic anhydride, dodecenyl succinic anhydride and n-hexadecenyl succinic anhydride.

The reactive sizes are usually used in the form of an aqueous dispersion. For example, alkyl ketene dimers are dispersed in an aqueous solution of a cationic starch, or nonionic or anionic emulsifiers are used to stabilize the alkyl ketene dimers. Depending on the type and amount of emulsifiers used or mixtures of mutually compatible emulsifiers, the resulting reactive size dispersions are cationically, neutral or anionically charged.

For example, anionic emulsifiers can be added to alkyl ketene dimer dispersions which have been emulsified in water with the aid of cationic starch. If the charge of the anionic emulsifiers outweighs the charge of the cationic emulsifiers, an anionically charged alkyl ketene dimer dispersion is obtained. anionic charged aqueous alkyldiketene dispersions are preferably prepared by emulsifying alkylketene dimers in aqueous solutions of anionic emulsifiers. Anionic emulsifiers which can be used are, for example, condensates of naphthalene sulfonic acid and formaldehyde, sulfonated polystyrene, C ₁ -C ₂₂ -alkylsulfuric acids, lignosulfonic acid, phenolsulfonic acid, naphthalenesulfonic acid or the sodium, potassium or ammonium salts of the acids mentioned. Copolymers of acrylic acid and maleic acid, homopolymers of acrylic acid, homopolymers of methacrylic acid, copolymers of isobutene and maleic acid and / or acrylic acid, hydrolyzed copolymers of isobutene or diisobutene and maleic anhydride are suitable emulsifiers for the preparation of anionic alkyl ketene dimer dispersions. The acid groups of the homo- and copolymers can, for example, be partially or completely neutralized with sodium hydroxide solution, potassium hydroxide solution or with ammonia and can be used in this form as anionic emulsifiers. The molecular weight M _{w of} the homo- and copolymers is, for example, 1000 to 15000 and is preferably in the range from 1500 to 10000. The emulsifiers are used, for example, in amounts of up to 3.5% by weight, preferably up to 2% by weight. -%, based on the reactive sizing agent to be dispersed.

The reactive sizing agents are optionally used in the mass sizing of the paper products to be used according to the invention as carrier material for the packaging materials. They are used particularly when packaging materials with particularly good edge penetration are required. They are then used in amounts that are usually required for the production of sized paper products, e.g. 0.1 to 2.0, preferably 0.1 to 0.5 wt .-%, based on dry cellulose fibers. Per 100 parts by weight of polymer sizing agent, for example 0 to 90 parts by weight, preferably 50 to 90 parts by weight, of reactive sizing agents are used. If mixtures of a polymer sizing agent dispersion and an aqueous dispersion of a reactive sizing agent are used, the mixtures each contain, based on the polymer content, for example 5 to 50, preferably 10 to 30% by weight of polymer (100%).

If reactive sizing agents are used together with a polymer sizing agent, the reactive sizing agents, preferably alkyl ketene dimer dispersions, can first be added to the paper stock and then the polymer sizing agent dispersions can be metered in. However, the alkyl ketene dimer dispersion and at least one polymer sizing agent dispersion can also be added to the paper stock at the same time and then dewatered to form a sheet, or a mixture of a reactive sizing agent such as at least one alkyl sizing agent dispersion and at least one polymer sizing agent dispersion is added to the paper stock and dewatered. then put it under leaf formation. The polymer sizing agents can of course also be used as surface sizing agents, for example by applying them to the surface of the paper using a size press or spraying them onto the surface of the paper.

The paper stock is additionally dewatered in the presence of a retention agent. In addition to anionic retention aids or nonionic retention aids such as polyacrylamides, cationic polymers are preferably used as retention aids and as drainage aids. This leads to a significant improvement in the runnability of the paper machines. All commercially available products for this purpose can be used as cationic retention agents. These are, for example, cationic polyacrylamides, polydiallyldimethylammonium chlorides, polyethyleneimines, polyamines with a molecular weight of more than 50,000, polyamines which may have been modified by grafting on ethyleneimine, polyetheramides, polyvinylimidazoles, polyvinylpyrrolidines, polyvinylimidazolines, polyvinyltetrahydropyrylamino, poly ( Poly (dialkylaminoalkyl (meth) acrylates) in protonated or quaternized form and also polyamidoamines from a dicarboxylic acid such as adipic acid and polyalkylene polyamines such as diethylenetriamine amine which are grafted with ethyleneimine and crosslinked with polyethylene glycol dichlorohydrin ethers according to the teaching of DE-B-24348amamido which have been reacted with epichlorohydrin to form water-soluble condensation products and copolymers of acrylamide or methacrylamide and dialkylaminoethyl acrylates or methacrylates, for example copolymers of acrylamide and dimethylamino ethyl acrylate in the form of the salt with hydrochloric acid or in the form quaternized with methyl chloride. Other suitable retention agents are so-called microparticle systems made from cationic polymers such as cationic starch and finely divided silica or from cationic polymers such as cationic polyacrylamide and bentonite.

The cationic polymers which are used as retention agents have, for example, K values according to Fikentscher of at least 140 (determined in 5% strength aqueous saline solution at a polymer concentration of 0.5% by weight, a temperature of 25 ° C. and a pH of 7). They are preferably used in amounts of 0.01 to 0.3% by weight, based on dry cellulose fibers.

At least one cationic polymer can optionally be added to the aqueous slurry of cellulose fibers in addition to the substances already mentioned. Examples of cationic polymers are polymers containing vinylamine units, polymers containing vinylguanidine units, polymers containing dialkylaminoalkyl (meth) acrylamide units, polyethyleneimines, polyamidoamines grafted with ethyleneimine and / or polydiallyldimethylammonium chlorides. The men The amount of cationic polymers is, for example, 0.001 to 2.0% by weight, preferably 0.01 to 0.1% by weight, based on dry cellulose fibers.

Polymers containing vinylamine units are known, cf. US-A-4,421,602, US-A-5,334,287, EP-A-0216387, US-A-5,981, 689, WO-A-00/63295 and US-A-6,121, 409. They are produced by hydrolysis of open-chain polymers containing N-vinylcarboxamide units. These polymers are e.g. obtainable by polymerizing N-vinylformamide, N-vinyl-N-methylformamide, N-vinylacetamide, N-vinyl-N-methylacetamide, N-vinyl-N-ethylacetamide and N-vinylpropionamide. The monomers mentioned can be polymerized either alone or together with other monomers.

Suitable monoethylenically unsaturated monomers which are copolymerized with the N-vinyicarboxamides are all compounds which can be copolymerized therewith. Examples include vinyl esters of saturated carboxylic acids of 1 to 6 carbon atoms such as vinyl formate, vinyl acetate, vinyl propionate and vinyl butyrate and vinyl ethers such as C to C ₆ alkyl vinyl ether, for example methyl or ethyl vinyl ether. Further suitable comonomers are esters, amides and nitriles of ethylenically unsaturated C ₃ to C ₆ carboxylic acids, for example methyl acrylate, methyl methacrylate, ethyl acrylate and ethyl methacrylate, acrylamide and methacrylamide and also acrylonitrile and methacrylonitrile.

Other suitable carboxylic acid esters are derived from glycols or polyalkylene glycols, only one OH group being esterified in each case, e.g. Hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate and acrylic acid monoesters of polyalkylene glycols with a molecular weight of 500 to 10000. Other suitable comonomers are esters of ethylenically unsaturated carboxylic acids such as dimethylamethylamethylethylaminoethylaminoethylaminoethylaminoethylamethylethylamate, such as aminoethylaminoethyl , Dimethylaminopropyl acrylate, Dimethylaminopropyl methacrylate, Diethylaminopropylacrylat, Dimethylaminobutylacrylat and Diethyaminobutylacrylat. The basic acrylates can be used in the form of the free bases, the salts with mineral acids such as hydrochloric acid, sulfuric acid or nitric acid, the salts with organic acids such as formic acid, acetic acid, propionic acid or the sulfonic acids or in quaternized form. Suitable quaternizing agents are, for example, dimethyl sulfate, diethyl sulfate, methyl chloride, ethyl chloride or benzyl chloride.

Other suitable comonomers are amides of ethylenically unsaturated carboxylic acids such as acrylamide, methacrylamide and N-alkyl mono- and diamides of monoethylenically unsaturated carboxylic acids with alkyl radicals of 1 to 6 carbon atoms, for example N- Methyl acrylamide, N, N-dimethylacrylamide, N-methyl methacrylamide, N-ethyl acrylamide, N-propylacrylamide and tert. Butylacrylamide and basic (meth) acrylamides, such as dimethylaminoethyl acrylamide, dimethylaminoethyl methacrylamide, diethylaminoethyl acrylamide, diethylaminoethyl methacrylamide, dimethylaminopropylacrylamide, diethylaminopropylacrylamide, dimethylaminopropyl methacrylamide and diethylaminopropyl methacrylamide.

Also suitable as comonomers are N-vinylpyrrolidone, N-vinylcaprolactam, acrylonitrile, methacrylonitrile, N-vinylimidazole and substituted N-vinylimidazoles such as e.g. N-vinyl-2-methylimidazole, N-vinyl-4-methylimidazole, N-vinyl-5-methylimidazole, N-vinyl-2-ethylimidazole and N-vinylimidazolines such as N-vinylimidazoline, N-vinyl-2-methylimidazoline and N- vinyl-2-ethylimidazoline. In addition to the free bases, N-vinylimidazoles and N-vinylimidazolines are also used in neutralized or in quaternized form with mineral acids or organic acids, the quaternization preferably being carried out with dimethyl sulfate, diethyl sulfate, methyl chloride or benzyl chloride. Diallyldialkylammonium halides such as e.g. Diallyldimethylammonium chloride.

The copolymers contain, for example

95 to 5 mol%, preferably 90 to 10 mol% of at least one N-vinylcarboxamide and

5 to 95 mol%, preferably 10 to 90 mol% of other monoethylenically unsaturated monomers copolymerizable therewith

in polymerized form. The comonomers are preferably free from acid groups.

In order to prepare polymers containing vinylamine units, one preferably starts from homopolymers of N-vinylformamide or from copolymers which are obtained by copolymerizing

N-vinylformamide with

Vinyl formate, vinyl acetate, vinyl propionate, acrylonitrile, N-vinyl caprolactam, N-vinyl urea, N-vinyl pyrrolidone or d- to C ₆ -alkyl vinyl ethers

and subsequent hydrolysis of the homo- or of the copolymers to form vinylamine units from the polymerized N-vinylformamide units are, the degree of hydrolysis being, for example, 5 to 100 mol%, preferably 70 to 100 mol%. The polymers described above are hydrolysed by known processes by the action of acids, bases or enzymes. When acids are used as hydrolysis agents, the vinylamine units of the polymers are present as ammonium salts, while the free amino groups are formed in the hydrolysis with bases.

In most cases, the degree of hydrolysis of the homo- and copolymers is 80 to 95 mol%. The degree of hydrolysis of the homopolymers is synonymous with the vinylamine units in the polymers. In the case of copolymers which contain vinyl esters in copolymerized form, in addition to the hydrolysis of the N-vinylformamide units, hydrolysis of the ester groups can occur with formation of vinyl alcohol units. This is particularly the case if the copolymers are hydrolysed in the presence of sodium hydroxide solution. Polymerized acrylonitrile is also chemically changed during the hydrolysis. This creates, for example, amide groups or carboxyl groups. The homo- and copolymers containing vinylamine units can optionally contain up to 20 mol% of amidine units which are formed, for example, by reaction of formic acid with two adjacent amino groups or by intramolecular reaction of an amino group with a neighboring amide group, for example of polymerized N-vinylformamide. The moimass M _{w of} the polymers containing vinylamine units is, for example, 500 to 10 million, preferably 1000 to 5 million (determined by light scattering). This molar mass range corresponds, for example, to K values of 5 to 300, preferably 10 to 250 (determined according to H. Fikentscher in 5% aqueous sodium chloride solution at 25 ° C. and a polymer concentration of 0.5% by weight).

The polymers containing vinylamine units are preferably used in salt-free form. Salt-free aqueous solutions of polymers containing vinylamine units can be prepared, for example, from the salt-containing polymer solutions described above with the aid of ultrafiltration on suitable membranes at separation limits of, for example, 1000 to 500,000 daltons, preferably 10,000 to 300,000 daltons. The aqueous solutions of other polymers containing amino and / or ammonium groups described below can also be obtained with the aid of ultrafiltration in a salt-free form.

Derivatives of polymers containing vinylamine units can also be used as cationic polymers. For example, it is possible to produce a large number of suitable derivatives from the polymers containing vinylamine units by amidation, alkylation, sulfonamide formation, urea formation, thiourea formation, carbamate formation, acylation, carboxymethylation, phosphonomethylation or Michael addition of the amino groups of the polymer. Are of particular interest here uncrosslinked polyvinylguanidines, which are obtained by reaction of polymers containing vinylamine units, preferably polyvinylamines, with cyanamide (R ¹ R ² N-CN, where R ¹ , R ² = H, d- to C -alkyl, C ₃ - to C ₆ -cycloalkyl , Phenyl, benzyl, alkyl-substituted phenyl or naphthyl) are accessible, cf. US-A-6,087,448, column 3, line 64 to column 5, line 14.

The polymers containing vinylamine units also include hydrolyzed graft polymers of, for example, N-vinylformamide on polyalkylene glycols, polyvinyl acetate, polyvinyl alcohol, polyvinylformamides, polysaccharides such as starch, oligosaccharides or monosaccharides. The graft polymers can be obtained by free-radically polymerizing, for example, N-vinylformamide in an aqueous medium in the presence of at least one of the graft bases mentioned, together with copolymerizable other monomers, and then hydrolyzing the grafted vinylformamide units to vinylamine units in a known manner.

Polymers of dialkylaminoalkyl (meth) acrylamides are also suitable as cationic polymers. Suitable monomers for the production of such polymers are, for example, dimethylaminoethyl acrylamide, dimethylaminoethyl methacrylamide, dimethylaminopropylacrylamide, dimethylaminopropyl methacrylamide, diethylaminoethyl acrylamide, diethylaminoethyl methacrylamide and diethylaminopropyl acrylamide. These monomers can be used in the polymerization in the form of the free bases, the salts with inorganic or organic acids or in quaternized form. They can be radically polymerized to give homopolymers or together with other copolymerizable monomers to give copolymers. The polymers contain, for example, at least 30 mol%, preferably at least 70 mol%, of the basic monomers mentioned in copolymerized form.

Other suitable cationic polymers are polyethyleneimines, which can be prepared, for example, by polymerizing ethyleneimine in aqueous solution in the presence of acid-releasing compounds, acids or Lewis acids as a catalyst. Polyethyleneimines, for example, have molecular weights of up to 2 million, preferably from 200 to 1,000,000. Polyethyleneimines with molecular weights of 500 to 750,000 are particularly preferably used. The polyethyleneimines can optionally be modified, for example alkoxylated, alkylated or amidated. They can also be subjected to Michael addition or plug synthesis. The derivatives of polyethyleneimines obtainable here are also suitable as cationic polymers. Polyamidoamines grafted with ethyleneimine are also suitable, which can be obtained, for example, by condensing dicarboxylic acids with polyamines and subsequently grafting ethyleneimine. Suitable polyamidoamines are obtained, for example, by reacting dicarboxylic acids with 4 to 10 carbon atoms with polyalkylene polyamines which contain 3 to 10 basic nitrogen atoms in the molecule. Examples of dicarboxylic acids are succinic acid, maleic acid, adipic acid, glutaric acid, suberic acid, sebacic acid or terephthalic acid. Mixtures of dicarboxylic acids can also be used in the preparation of the polyamidoamines, as can mixtures of several polyalkylene polyamines. Suitable polyalkylene polyamines are, for example, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenetriamine, tripropylenetetramine, dihexamethylenetriamine, aminopropylethylenediamine and bis-aminopropylethylenediamine. To produce the polyamidoamines, the dicarboxylic acids and polyalkylene polyamines are heated to higher temperatures, for example to temperatures in the range from 120 to 220, preferably 130 to 180 ° C. The water generated during the condensation is removed from the system. Lactones or lactams of carboxylic acids having 4 to 8 carbon atoms can optionally also be used in the condensation. For example, 0.8 to 1.4 moles of a polyalkylene polyamine are used per mole of a dicarboxylic acid. These polyamidoamines are grafted with ethyleneimine. The grafting reaction is carried out, for example, in the presence of acids or Lewis acids such as sulfuric acid or boron trifluoride etherates at temperatures of, for example, 80 to 100.degree. Compounds of this type are described for example in DE-B-24 34 816.

The optionally crosslinked polyamidoamines, which may have been additionally grafted with ethyleneimine before crosslinking, are also suitable as cationic polymers. The crosslinked polyamidoamines grafted with ethyleneimine are water-soluble and have, for example, an average molecular weight M _w of 3000 to 2 million daltons. Typical crosslinkers are, for example, epichlorohydrin or bischlorohydrin ethers of alkylene glycols and polyalkylene glycols.

Polyallylamines are also suitable as cationic polymers. Polymers of this type are obtained by homopolymerizing allylamine, preferably in a form neutralized with acids, or by copolymerizing allylamine with other monoethylenically unsaturated monomers described above as comonomers for N-vinylcarboxamides.

Also suitable are water-soluble crosslinked polyethyleneimines which are obtainable by reacting polyethyleneimines with crosslinkers such as epichlorohydrin or bischlorohydrin ethers of polyalkylene glycols having 2 to 100 ethylene oxide and / or propylene oxide units and still have free primary and / or secondary amino groups. Amidic polyethyleneimines which are obtainable, for example, by amidating polyethyleneimines with d- to ds-monocarboxylic acids are also suitable. Other suitable cationic polymers are alkylated polyethyleneimines and alkoxylated polyethyleneimines. In alkoxylation, 1 to 5 ethylene oxide or propylene oxide units are used, for example, per NH unit in polyethyleneimine.

The above-mentioned cationic polymers have e.g. K values from 8 to 300, preferably 15 to 180 (determined according to H. Fikentscher in 5% aqueous saline solution at 25% and a polymer concentration of 0.5% by weight). At a pH of 4.5, for example, they have a charge density of at least 1, preferably at least 4 meq / g polyelectrolyte.

Cationic polymers which are preferred are polymers containing vinylamine units and polyethyleneimines. Examples for this are:

Vinylamine homopolymers, 10 to 100% hydrolyzed polyvinylformamides, partially or completely hydrolyzed copolymers of vinylformamide and vinyl acetate, vinyl alcohol, vinylpyrrolidone or acrylamide, each with molecular weights from 3,000 to 2,000,000 and

Polyethyleneimines, crosslinked polyethyleneimines or amidated polyethyleneimines, each of which has a molecular weight of 500 to 3,000,000.

The polymer content of the aqueous solution is, for example, 1 to 60, preferably 2 to 15 and usually 5 to 10% by weight.

Cardboard is usually produced by dewatering a slurry of cellulose fibers. The use of kraft pulp is preferred. The use of TMP and CTMP is also of particular interest. The pH of the cellulose fiber slurry is, for example, 4 to 8, preferably 6 to 8. The paper stock can be dewatered discontinuously or continuously on a paper machine. The order of addition of cationic polymer, bulk sizing agent and retention agent can be chosen arbitrarily. However, a procedure is preferred in which the retention agent and then the cationic polymer, preferably polyvinylamine, and then at least one reactive sizing agent such as alkyl ketene dimer, alkyl or alkenyl succinic anhydride in combination with an aluminum compound or a mixture of these sizing agents and a polymer sizing agent are added to the aqueous cellulose fiber slurry added. According to another embodiment, at least one polymer sizing agent is metered in first, then the retention agent and finally the cationic polymer. In the production of the paper products to be used according to the invention, other auxiliaries which are usually suitable can also be used, for example fixing agents, dyes, bactericides and dry and / or wet strength agents for paper.

After the paper stock has been dewatered and the paper product has been dried, a cardboard which is sized in mass and has a basis weight of 80 to 400 g / m ² , preferably 120 to 220 g / m ^{2, is obtained} . The box is coated on one or both sides with a film made of plastic or metal such as aluminum.

Suitable plastic films can be made from polyethylene, polypropylene, polyamide or polyester. For example, the foils can be bonded to the glued paper products using an adhesive. In such cases, films are usually used, which are coated with an adhesive, and the composite is pressed. However, one can also coat the surface of the sized paper products with an adhesive and then apply the films on one or both sides and press the resulting composite. However, the films can also be processed directly by the action of heat and pressure with the cardboard to form a composite, from which the suitable structures for the production of the packaging for liquids are then cut out. The packaging is preferably used in the food sector, e.g. for packaging drinks such as mineral water, juices or milk or for the production of drinking vessels such as cups. It is important for these packages that they have good edge penetration, i.e. the box should absorb as little or practically no liquid as possible. The adhesion of foils to paper products sized with polymer sizing agents is better than that of foils to paper products sized exclusively with alkyl ketene dimers.

Unless the context indicates otherwise, the percentages in the examples mean percentages by weight. The K values were determined according to H. Fikentscher, Cellulose-Chemie, Vol. 13, 58-64 and 71-74 (1932) in 5% aqueous saline solution at a temperature of 25 ° C. and a pH of 7 determined at a polymer concentration of 0.5 wt .-%. The molecular weights Mw of the polymers were measured by light scattering. Examples

Determination of edge penetration

The cardboard produced is laminated on both sides with an adhesive tape made of polyethylene. The thickness of the cardboard is then determined. Test strips of size 25 x 75 mm are then cut from the box and weighed in each case. In order to determine the edge penetration, the test strips are immersed in a bath containing a 30% hydrogen peroxide solution heated to 70 ° C. The test strips are removed from the bath after a dwell time of 10 minutes. Excess hydrogen peroxide is absorbed with filter paper. The test strips are weighed again. The edge penetration in kg / m ² is then calculated from the weight increase.

Ink flotation time

The ink floating time (measured in minutes) is the time it takes a test ink according to DIN 53126 to reach 50% through a test sheet.

Cobb value

Determination was carried out in accordance with DIN 53 132 by storing the paper sheets in water for a period of 60 seconds. The water absorption is given in g / m ² .

Examples 1 to 6

To a paper stock with a consistency of 10 g / l made of 100% unbleached pine sulfate pulp with a freeness of 20 ° SR (Schopper-Riegler), 0.75% of a cationic starch (Solvitose BPN ) as a retention agent and adjusted the pH of the mixture to 7. The amounts of stearyldiketene given in the table were then metered in in the form of an aqueous dispersion (Basoplast® 4118MC) and an aqueous dispersion of the polymer sizing agents also listed in Table 1. The fiber slurries were each mixed and dewatered on a Rapid-Koethen sheet former. Sheets with a basis weight of 150 g / m ^{2 were obtained} .

The following polymer sizes were used:

Polymer sizing agent A: Basoplast® 250D (aqueous dispersion of a copolymer, produced by emulsion polymerization of acrylonitrile and n-butyl acrylate in Presence of degraded cationic starch as an emulsifier and hydrogen peroxide as an initiator).

Polymer sizing agent B: Basoplast® 265D (aqueous dispersion of a copolymer, produced by emulsion polymerization of styrene and n-butyl acrylate in the presence of degraded cationic starch as emulsifier and hydrogen peroxide as initiator).

Polymer sizing agent C: Basoplast® PR8172 (aqueous dispersion of a copolymer, produced by emulsion polymerization of styrene and n-butyl acrylate in the presence of cationic starch as emulsifier and hydrogen peroxide as initiator).

Table 1

The leaves were then dried on a steam-heated drying cylinder at a temperature of 90 ° C to a water content of 6-10%. After drying, the Cobb value of the leaves was determined. The sheets were then laminated on both sides with an adhesive tape made of polyethylene with a density of 0.918 g / cm ³ (heating the composite under pressure to 30 ° C.). The edge penetration of the three-layer composite was then determined. The results are shown in Table 3.

Comparative Examples 1 to 4

To a paper stock with a consistency of 10 g / l made from 100% unbleached pine sulfate pulp with a freeness of 20 ° SR (Schopper-Riegler), 0.75% of a cationic starch (Solvitose BPN) was added, each based on dry paper stock as a retention aid and adjusted the pH of the mixture to 7. The amounts of stearyl diketene given in Table 2 were then metered in in the form of an aqueous dispersion (Basoplast® 4118MC). Then they were mixed aqueous fiber slurries and dewatered them on a Rapid-Koethen sheet former to give a paper product with a basis weight of 150 g / m ² .

Table 2

The leaves were then dried on a steam-heated drying cylinder at a temperature of 90 ° C to a water content of 6-10%. After drying, the Cobb value of the leaves was determined. The sheets were then glued on both sides with an adhesive tape made of polyethylene (pressing the composite under pressure). The edge penetration of the three-layer composite against hydrogen peroxide was then determined. The results are shown in Table 3.

Table 3

Claims

claims

1. Packaging material made of an at least two-layer composite of sized paper or sized cardboard and at least one water-impermeable film for the production of containers for the packaging of liquids, characterized in that the paper or the box is sized with a polymer sizing agent.

2. Packaging material according to claim 1, characterized in that the paper or the cardboard is sized in the mass with a polymer sizing agent.

3. Packaging material according to claim 1, characterized in that the paper or the cardboard is sized in the surface with a polymer sizing agent.

4. Packaging material according to claim 1, characterized in that the paper or cardboard is additionally sized in the presence of aqueous dispersions of reactive sizing agents and / or combinations of resin size and alum.

5. Packaging material according to claim 1 or 2, characterized in that the paper or cardboard is obtainable by adding aqueous alkyl ketene dispersions and aqueous polymer sizing agent dispersions in succession to the pulp and dewatering the pulp on the wire of a paper machine.

6. Packaging material according to one of claims 1 or 2, characterized in that the paper or the cardboard is obtainable by simultaneous addition of aqueous alkyl ketene dimer dispersions and aqueous polymer size dispersions for the paper stock and dewatering of the paper stock on the wire of a paper machine ,

7. Packaging material according to claim 1 or 2, characterized in that the paper or the cardboard is obtainable by sizing with a sizing agent mixture of an aqueous polymer sizing agent dispersion and an aqueous alkyl ketene dimer dispersion.

8. Packaging material according to one of claims 1 to 7, characterized in that the paper or cardboard is additionally sized in the presence of cationic polymers.

9. Packaging material according to one of claims 1 to 8, characterized in that the paper or the cardboard is laminated on both sides with a water-impermeable film made of plastic and / or metal.

10. Packaging material according to one of claims 1 to 9, characterized in that the paper or the cardboard on one or both sides with a film of polyethylene, polypropylene, copolymer of ethylene and propylene, polyester, polyvinyl alcohol, copolymer of ethylene and Vinyl acetate, copolymer of ethylene and vinyl alcohol, polyamide and / or aluminum is laminated.

11. Packaging material according to one of claims 1 to 8, characterized in that the paper or cardboard has a basis weight of 80 to 400 g / m ² and is laminated on both sides with a film made of polyethylene.

12. Use of paper products that are available through

(i) mass sizing of a paper stock from an aqueous slurry of cellulose fibers with at least one polymer sizing agent or with a polymer sizing agent and an aqueous dispersion of an alkyl ketene dimer or mixtures thereof in the presence of a retention aid and optionally a water-soluble aluminum compound and optionally at least one cationic polymer, (ii) dewatering the Paper stock on the wire of a paper machine, (iii) drying the paper product and

(iv) laminating the paper product on one or both sides with a film made of a plastic or metal,

for the production of containers for the packaging of liquids, in particular beverages.