EP1815064A1

EP1815064A1 - Packaging material comprising a coating with microcapsules

Info

Publication number: EP1815064A1
Application number: EP05820652A
Authority: EP
Inventors: Gabriele Lang-Wittkowski; Peter Schlichting; Ekkehard Jahns; Norbert Heidinger
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2004-11-17
Filing date: 2005-11-15
Publication date: 2007-08-08
Also published as: WO2006053714A1; JP2008520459A; US20090148575A1

Abstract

The invention relates to a packaging material in the form of a composite, comprising at least one support made from paper or cardboard, on which at least one layer of a paper coating slip, optionally a printed layer, optionally one or more thermoplastic layers and optionally one or more further layers are applied, whereby micro-encapsulated latent heat storage material is contained in at least one of said applied layers and the capsule wall of the micro-encapsulated latent heat storage material is made from 10 to 100 wt. % of one or more C1-C24 alkyl esters of acrylic and/or methacrylic acid (monomer I), 0 to 80 wt. % of a bi- or poly-functional monomer (monomer II), which is insoluble or barely soluble in water and 0 to 90 wt. % of other monomers (monomer III), each in relation to the total weight of the monomers, a method for production and use thereof for the packaging of foodstuffs.

Description

PACKAGING MATERIAL CONTAINS A COATING WITH MICROPHONES

description

The present invention relates to a packaging material in the form of a composite comprising at least one carrier made of paper or cardboard, to which at least one paper coating slip layer, optionally a printing layer, optionally one or more thermoplastic layers and optionally one or more further layers are applied, processes for their preparation and their use for food packaging. It further relates to a paper coating slip, a printing ink and a thermoplastic layer to be used according to the invention.

For the transport of temperature-sensitive products are well insulated packaging materials such as Styrofoam ^® (manufactured by BASF Aktiengesellschaft), Neopor ^® are typically (manufacturer BASF Aktiengesellschaft) or expanded polypropylene. The insulation is based on the poor heat conduction of these materials. However, a disadvantage is the large volume of these insulating materials. In the packaging industry, it is often important to transport or store as much product per unit volume as possible and not to generate transportation or storage costs for bulky packaging. Especially in the food sector with rather low-priced goods voluminous packaging are uneconomical.

On the other hand, foods are often very sensitive to interrupting their cold chain. In order to counterbalance such temperature jumps, there have been attempts in the past

Integrate latent heat storage material into the packaging. The operation of latent heat storage is based on the transformation enthalpy occurring during the solid / liquid phase transition, which means an energy absorption or energy release to the environment. They can thus be used for temperature maintenance in a defined temperature range.

This principle was exploited in the use of microcapsules having a capsule wall of a highly crosslinked methacrylic ester polymer and a latent heat storage core in coating compositions for paper (basis weight 40 g / m ² ) for thermal printing processes, as described in EP-A-1 029 018.

Furthermore, JP 2001 357250 describes building applications in which cardboard with microencapsulated latent heat storage material is used as floor, wall and ceiling material. The microcapsules based on urea-formaldehyde resin and melamine-formaldehyde resin are added to the paperboard during paperboard production. However, melamine- or urea-formaldehyde-based microcapsules are undesirable because of possible formaldehyde emissions. WO-A-0292911 teaches a paper or paperboard composition containing wet-laid short fibers and microencapsulated latent heat storage materials and the use of the soles or wrappers papers.

WO-A-03002424 teaches a paper-based packaging material to which microcapsules are added to the paper pulp.

EP 764 081 teaches a thermal barrier of two spaced trays with intervening compartments filled with latent heat storage material which may be microencapsulated.

JP-A-2001 097459 teaches the coating of a polyester fiber fleece with microencapsulated latent heat storage materials. The obtained nonwoven fabric is then laminated with an air cushion layer and a bag for medicaments or foodstuffs formed therefrom. Furthermore, there is talk of raw paper whose sizing agent contains microencapsulated latent heat storage material.

Attempts to integrate latent heat storage materials into packages are described in WO-A-97/23968 and GB-A-2336899. WO-A-97/23968 teaches a holding tank, in the bottom of which containers with latent heat storage material are located. GB-A-2336899 teaches a warming device, such as a plate, having in its bottom a cavity filled with latent heat storage material.

However, such additional voids or heat storage significantly increase the overall volume of the device. In addition, their construction is very complex and too complicated and expensive for simple disposable items.

Finally, JP 2003 2237848 teaches a food container with a resin composition applied to the container surface. The resin composition contains microencapsulated latent heat storage material with a capsule wall based on acrylates without going into detail on concrete acrylate compositions as wall material.

The object of the present invention was to provide a paper-based packaging material, preferably a formaldehyde-free packaging material, from which the conventional packaging containers can be molded and which can additionally store heat from the environment so as to keep the goods stored therein cool. Accordingly, a packaging material comprising at least one carrier made of paper or cardboard onto which at least one paper coating slip layer, if appropriate a printing layer, optionally one or more thermoplastic layers and optionally one or more further layers are applied, wherein at least one of the applied layers microencapsulated Latentwärme¬ storage material contains, found.

In particular, a packaging material in the form of a composite comprising at least one carrier made of paper or cardboard, to which at least one paper coating slip layer, optionally a printing layer, optionally one or more thermoplastic layers and optionally one or more further layers are applied, wherein at least one of the applied Layers micro-encapsulated latent heat storage material is contained and the capsule wall of the microencapsulated latent heat storage material is constructed

10 to 100 wt .-% of one or more dC _Σ ^ alkyl esters of acrylic and / or

Methacrylic acid (monomers I),

0 to 80% by weight of a bifunctional or polyfunctional monomer (monomer II) which is insoluble or sparingly soluble in water and 0 to 90% by weight of other monomers (monomer III)

in each case based on the total weight of the monomers found.

The microcapsules according to the invention are particles with a capsule core consisting predominantly, to more than 95 wt .-%, of latent heat storage material and a polymer as a capsule wall. The capsule core is solid or liquid depending on the temperature. The average particle size of the capsules (Z means by means of light scattering) is 0.5 to 100 μm, preferably 1 to 80 μm, in particular 1 to 50 μm. The weight ratio of capsule core to capsule wall is generally from 50:50 to 95: 5. Preferred is a core / wall ratio of 70:30 to 93: 7.

By definition, latent heat storage materials are substances which have a phase transition in the temperature range in which heat transfer is to be carried out. Preferably, the latent heat materials a solid / liquid phase transition in the temperature range of -30 to 3O ⁰ C, in particular from -30 to 2O ⁰ C and very particularly preferably from -30 to ⁰ to 10 C, depending on the desired application. As a rule, the latent heat storage material is an organic, preferably lipophilic substance.

Suitable substances may be mentioned by way of example: aliphatic hydrocarbon compounds, such as saturated or unsaturated C 10 -C ₄₀ -hydrocarbons, which are branched or preferably linear, for example, such as n-tetradecane, n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, n-nonadecane, n-eicosane, n-heneicosane, n-docosane, n-tricosane, n-tetracosane, n-pentacosane, n-hexacosane, n-heptacosane, n-octacosane and cyclic

Hydrocarbons, e.g. Cyclohexane, cyclooctane, cyclodecane;

aromatic hydrocarbon compounds such as benzene, naphthalene, biphenyl, o- or m-terphenyl, C ₁ -C ₄ o-alkyl-substituted aromatic hydrocarbons such as dodecylbenzene, tetradecylbenzene, hexadecylbenzene, hexylnaphthalene or

decylnaphthalene;

saturated or unsaturated C ₆ -C ₃ o-fatty acids such as lauric, stearic, oleic or behenic acid, preferably eutectic mixtures of decanoic acid with for example, myristic, palmitic or lauric acid;

Fatty alcohols such as lauryl, stearyl, oleyl, myristyl, cetyl alcohol, mixtures such as coconut fatty alcohol and the so-called oxo alcohols, which are obtained by hydroformylation of α-olefins and further reactions;

C ₆ -C ₃ o-fatty amines such as decylamine, dodecylamine, tetradecylamine or hexadecylamine;

Esters such as C ₁₀ alkyl esters of fatty acids such as propyl palmitate, methyl stearate or methyl palmitate and preferably their eutectic mixtures or

methyl cinnamate;

natural and synthetic waxes such as montanic acid waxes, montan ester waxes, carnauba wax, polyethylene wax, oxidized waxes, polyvinyl ether wax, ethylene vinyl acetate wax or Fischer-Tropsch wax waxes;

Method;

halogenated hydrocarbons such as chlorinated paraffin, bromoctadecane, bromopentadecane, bromononadecane, bromeicosane, bromodocosane.

Furthermore, mixtures of these substances are suitable, as long as it does not come to a melting point lowering outside the desired range, or the heat of fusion of the mixture is too low for a meaningful application.

Advantageously, for example, the use of pure n-alkanes, n-alkanes with a purity of greater than 80% or of alkane mixtures, as obtained as a technical distillate and are commercially available as such. Furthermore, it may be advantageous to add soluble compounds to the capsule core-forming substances so as to prevent the freezing point depression which sometimes occurs with the nonpolar substances. It is advantageous to use, as described in US Pat. No. 5,456,852, compounds having a melting point 20 to 120 K higher than the actual core substance. Suitable compounds are the fatty acids mentioned above as lipophilic substances, fatty alcohols, fatty amides and aliphatic hydrocarbon compounds. They are added in amounts of from 0.1 to 10% by weight, based on the capsule core.

The latent heat storage material is selected depending on the temperature range in which the heat storage is desired. For example, used for frozen food latent heat storage materials whose solid / liquid phase transition in the temperature range of -30 to 0 ⁰ C is. For temperature stabilization of fresh goods, for example dairy products, latent heat storage material with a phase transition in the temperature range from 0 to 15 ^° C. is preferably used. Trains t is Bevor¬ therefore a material having a transformation temperature in the range -30 to 30 ⁰ C, preferably ⁰ to 20 C, in particular -20 to 15 ° C. In this case, the choice of the transformation temperature may be dependent, for example, on the desired ambient temperature and the type of interruption of the cold chain. If, for example, it is to be avoided that there is no interruption during the cold chain, as when placing it on the shelves of the retailer, it is advantageous to choose a transformation temperature close to the desired storage temperature for frozen goods in the range from -20 to 0 ^° C. and for normal refrigerated goods in the range of 0 to 15 ° C. Should be on the other side in the foreground that the cooling or

Fresh produce survives a short drive in a overheated car of the buyer, so conversion temperatures up to 20 ⁰ C are sufficient. In addition, microencapsulated latent heat storage materials offer the advantage of mixing different microcapsules with latent heat storage material of different temperatures in order to meet an even more specific requirement profile.

Preferred latent heat storage material are aliphatic hydrocarbons particularly preferably those enumerated above by way of example. In particular, aliphatic hydrocarbons having 10 to 17 carbon atoms and mixtures thereof are preferred.

In principle, the materials known for the microcapsules for copying papers can be used as the polymer for the capsule wall. Thus, for example, it is possible to encapsulate the latent heat storage materials in gelatin with other polymers according to the processes described in GB-A 870476, US Pat. No. 2,800,457, US Pat. No. 3,041,289. Preferred wall materials, since they are very resistant to aging, are thermosetting polymers. Under thermosetting wall materials are to be understood that do not soften due to the high degree of crosslinking, but decompose at high temperatures. Suitable thermosetting wall materials are, for example, highly crosslinked formaldehyde resins, highly crosslinked polyureas and highly crosslinked polyurethanes and highly crosslinked methacrylic acid ester polymers.

Formaldehyde resins are understood as meaning reaction products of formaldehyde with

- Triazines such as melamine

Carbamides such as urea

Phenols such as phenol, m-cresol and resorcinol

Amino and amido compounds such as aniline, p-toluenesulfonamide, ethyleneurea and guanidine,

or their mixtures.

Formaldehyde resins which are preferred as capsule wall material are urea-formaldehyde resins, urea-resorcinol-formaldehyde resins, urea-melamine resins and melamine-formaldehyde resins. Likewise preferred are the C 1 -C ₄ -alkyl, in particular methyl ethers of these formaldehyde resins and the mixtures with these formaldehyde resins. In particular, melamine-formaldehyde resins and / or their methyl ethers are preferred.

In the methods known from copying papers, the resins are used as prepolymers. The prepolymer is still soluble in the aqueous phase and migrates in the course of the polycondensation at the interface and surrounds the oil droplets. Processes for microencapsulation with formaldehyde resins are well known and described for example in EP-A-562 344 and EP-A-974 394.

Capsule walls of polyureas and polyurethanes are also known from the copying papers. The capsule walls are formed by reaction of NH ₂ groups or OH-containing reactants with di- and / or polyisocyanates. Suitable isocyanates are, for example, ethylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate and 2,4- and 2,6-

Toluene diisocyanate. Also mentioned are polyisocyanates such as biuret derivatives, polyuretonimines and isocyanurates. Suitable reactants are: hydrazine, guanidine and its salts, hydroxylamine, di- and polyamines and amino alcohols. Such interfacial polyaddition processes are known, for example, from US 4,021,595, EP-A 0 392 876 and EP-A 0 535 384. Preference is given to microcapsules whose capsule wall is a highly crosslinked methacrylic ester polymer. The degree of crosslinking is achieved with a crosslinker> 10 wt .-% based on the total polymer.

In the preferred microcapsules, the wall-forming polymers are from 10 to

100 wt .-%, preferably 30 to 95 wt .-% of one or more C ₁ -C ₂₄ alkyl esters of acrylic and / or methacrylic acid as monomers I constructed. In addition, the polymers may contain up to 80% by weight, preferably 5 to 60% by weight, in particular 10 to 50% by weight, of a bi- or polyfunctional monomer as monomers II, which is insoluble or sparingly soluble in water, incorporated in copolymerized form. In addition, the polymers may contain up to 90% by weight, preferably up to 50% by weight, in particular up to 30% by weight, of other monomers III in copolymerized form.

Suitable monomers I are C 1 -C ₂₄ -alkyl esters of acrylic and / or methacrylic acid. Particularly preferred monomers I are methyl, ethyl, n-propyl and n-butyl acrylate and / or the corresponding methacrylates. Iso-propyl, isobutyl, sec-butyl and tert-butyl acrylate and the corresponding methacrylates are preferred. Further, methacrylonitrile is mentioned. Generally, the methacrylates are preferred.

Suitable monomers II are bi- or polyfunctional monomers which are insoluble or sparingly soluble in water but have good to limited solubility in the lipophilic substance. Sparingly is less than 60 g / l to understand at 2O ⁰ C a solubility. By bi- or polyfunctional monomers is meant compounds having at least 2 non-conjugated ethylenic double bonds. In particular, divinyl and polyvinyl monomers come into consideration, which cause cross-linking of the capsule wall during the polymerization.

Preferred bifunctional monomers are the diesters of diols with acrylic acid or methacrylic acid, furthermore the diallyl and divinyl ethers of these diols.

Preferred divinyl monomers are ethanediol diacrylate, divinylbenzene, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, methallyl methacrylamide and allyl methacrylate. Particular preference is given to propanediol, butanediol, pentanediol and hexanediol diacrylate or the corresponding methacrylates.

Preferred polyvinyl monomers are trimethylolpropane triacrylate and methacrylate, pentaerythritol triallyl ether and pentaerythritol tetraacrylate.

As monomers III, other monomers come into consideration, preference is given to monomers IHa such as vinyl acetate, vinyl propionate and vinylpyridine. _G

Particularly preferred are the water-soluble monomers INb, e.g. Acrylonitrile, methacrylamide, acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, N-vinylpyrrolidone, 2-hydroxyethyl acrylate and methacrylate and acrylamido-2-methylpropanesulfonic acid. In addition, N-methylolacrylamide, N-methylolmethacrylamide, dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate may be mentioned in particular.

According to a further preferred embodiment, the wall-forming polymers of 30 to 90 wt .-% methacrylic acid, 10 to 70 wt .-% of an alkyl ester of (meth) acrylic acid, preferably methyl methacrylate, tert-butyl methacrylate, phenyl methacrylate and cyclohexyl methacrylate, and 0 to 40 wt .-% further ethylenically unsaturated monomers formed. These further ethylenically unsaturated monomers may be the monomers I, II or III hitherto not mentioned for this embodiment. Since they usually have no significant influence on the microcapsules of this embodiment formed, their proportion is preferably <20 wt .-%, in particular <10 wt .-%. Such microcapsules and their preparation are described in EP-A-1 251 954, to which reference is expressly made.

The microcapsules suitable for use according to the invention can be prepared by a so-called in situ polymerization.

The preferred microcapsules and their preparation are known from EP-A-457 154, DE-A-10 139 171, DE-A-102 30 581 and EP-A-1 321 182, to which reference is expressly made. Thus, the microcapsules are prepared by preparing from the monomers, a radical initiator, a protective colloid and the lipophilic substance to be encapsulated a stable oil-in-water emulsion in which they are present as a disperse phase. Subsequently, the polymerization of the monomers is initiated by heating and controlled by further increase in temperature, wherein the resulting polymers form the capsule wall, which encloses the lipophilic substance.

In general, the polymerization is carried out at 20 to 100 ° C, preferably at 40 to 8O ⁰ C. Of course, the dispersion and polymerization temperature should be above the melting temperature of the lipophilic substances.

After reaching the final temperature, the polymerization is expediently continued for a time of up to 2 hours in order to reduce residual monomer contents. Following the actual polymerization reaction at a conversion of 90 to 99% by weight, it is generally advantageous to make the aqueous microcapsule dispersions substantially free of odor carriers, such as residual monomers and other organic volatile constituents. This can be done physically in a manner known per se by distillative removal (in particular via steam). distillation) or by stripping with an inert gas. Furthermore, it can be done chemically, as described in WO 9924525, advantageously by redox-initiated polymerization, as described in DE-A-4 435 423, DE-A-4419518 and DE-A-4435422.

It is possible in this way to produce microcapsules having an average particle size in the range from 0.5 to 100 .mu.m, it being possible to adjust the particle size in a manner known per se by means of the shearing force, the stirring speed, the protective colloid and its concentration.

Preferred protective colloids are water-soluble polymers, since these reduce the surface tension of the water from 73 mN / m to a maximum of 45 to 70 mN / m and thus ensure the formation of closed capsule walls and microcapsules with preferred particle sizes between 1 and 30 .mu.m, preferably 3 and 12 μm, form.

In general, the microcapsules are prepared in the presence of at least one organic protective colloid, which may be both anionic and neutral. It is also possible to use anionic and nonionic protective colloids together. Preference is given to using inorganic protective colloids, optionally mixed with organic protective colloids or nonionic protective colloids.

Organic neutral protective colloids are cellulose derivatives such as hydroxyethylcellulose, methylhydroxyethylcellulose, methylcellulose and carboxymethylcellulose, polyvinylpyrrolidone, copolymers of vinylpyrrolidone, gelatin, gum arabic, xanthan, sodium alginate, casein, polyethylene glycols, preferably polyvinyl alcohol and partially hydrolyzed polyvinyl acetates and methylhydroxypropylcellulose.

Suitable anionic protective colloids are polymethacrylic acid, the copolymers of sulfoethyl acrylate and methacrylate, sulfopropyl acrylate and methacrylate, N- (sulfoethyl) -maleimide, 2-acrylamido-2-alkylsulfonic acids, styrenesulfonic acid and vinylsulfonic acid.

Preferred anionic protective colloids are naphthalenesulfonic acid and naphthalenesulfonic acid-formaldehyde condensates and above all polyacrylic acids and phenolsulfonic acid-formaldehyde condensates.

The anionic and nonionic protective colloids are generally used in amounts of from 0.1 to 10% by weight, based on the water phase of the emulsion.

Preference is given to inorganic protective colloids, so-called Pickering systems, which allow stabilization by very fine solid particles and insoluble in water, but are dispersible or insoluble and not dispersible in water but wettable by the lipophilic substance.

The mode of action and its use is described in EP-A-1 029 018 and EP-A-1 321 182, to the contents of which reference is expressly made.

A Pickering system can consist of the solid particles alone or in addition of auxiliaries which improve the dispersibility of the particles in water or the wettability of the particles by the lipophilic phase.

The inorganic solid particles may be metal salts, such as salts, oxides and hydroxides of calcium, magnesium, iron, zinc, nickel, titanium, aluminum, silicon, barium and manganese. These include magnesium hydroxide, magnesium carbonate, magnesium oxide, calcium oxalate, calcium carbonate, barium carbonate, barium sulfate, titanium dioxide, aluminum oxide, aluminum hydroxide and zinc sulfide. Silicates, bentonite, hydroxyapatite and hydrotalcites are also mentioned. Particularly preferred are highly disperse silicas, magnesium pyrophosphate and tricalcium phosphate.

The Pickering systems can both be added to the water phase first, as well as added to the stirred oil-in-water emulsion. Some fine, solid particles are produced by precipitation as described in EP-A-1 029 018 and EP-A-1 321 182.

The highly dispersed silicas can be dispersed as fine, solid particles in water. But it is also possible to use so-called colloidal dispersions of silica in water. The colloidal dispersions are alkaline, aqueous mixtures of silica. In the alkaline pH range, the particles are swollen and stable in water. For use of these dispersions as Pickering system, it is advantageous if the pH of the oil-in-water emulsion is adjusted to pH 2 to 7 with an acid.

The inorganic protective colloids are generally used in amounts of 0.5 to 15 wt .-%, based on the water phase.

In general, the organic neutral protective colloids are used in amounts of from 0.1 to 15% by weight, preferably from 0.5 to 10% by weight, based on the water phase.

The dispersing conditions for preparing the stable oil-in-water emulsion are preferably chosen in a manner known per se such that the oil droplets have the size of the desired microcapsules. The microcapsule dispersions obtained by the polymerization give a free-flowing capsule powder when spray-dried. The spray drying of the microcapsule dispersion can be carried out in the usual way. In general, the procedure is such that the inlet temperature of the hot air flow in the range of 100 to 200 ⁰ C, preferably 120 to 160 ⁰ C, and the outlet temperature of the Warmluft¬ stream in the range of 30 to 90 ⁰ C, preferably 60 to 80 ⁰ C. , The spraying of the aqueous polymer dispersion in the stream of hot air can take place, for example, by means of single-fluid or multi-fluid nozzles or via a rotating disk. The deposition of the polymer powder is usually carried out using cyclones or filter separators. The sprayed aqueous polymer dispersion and the hot air stream are preferably conducted in parallel.

Optionally, spray-auxiliaries are added to the spray-drying in order to facilitate the spray-drying or to set certain powder properties, e.g. Low dust, free-flowing or improved redispersibility. A variety of spraying aids are familiar to the person skilled in the art. Examples thereof can be found in DE-A 19629525, DE-A 19629526, DE-A 2214410, DE-A 2445813, EP-A 407889 or EP-A 784449. Advantageous spray aids are, for example, water-soluble polymers of the polyvinyl alcohol or partially hydrolyzed polyvinyl acetates, cellulose derivatives such as Hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, methylhydroxyethylcellulose and methylhydroxypropylcellulose, polyvinylpyrrolidone, copolymers of vinylpyrrolidone, gelatin, preferably polyvinyl alcohol and partially hydrolyzed polyvinyl acetates and methylhydroxypropylcellulose.

The packaging material according to the invention is made of paper or

Carton and the paper coating layer built. In general, however, it contains the carrier and two, three or more layers.

The packaging material according to the invention contains a total of 5 to 300 g / m ² (coating weight as dry weight), preferably 15 to 200 g / m ² and particularly preferably 30 to 150 g / m ² microencapsulated latent heat storage material.

The packaging materials according to the invention, in particular those for food, have a thickness of 0.01 to 20 mm, preferably 0.1 to 10 mm, in particular 0.5 to 2 mm.

The basic structure of a food packaging material can be composed of a thermoplastic layer, preferably low-density polyethylene, a printing layer, a paper coating slip layer, a carrier layer of paper and a thermoplastic layer, from the outside to the inside. Between the thermoplastic layer and the paper support, one or more additional layers may be present to achieve special properties, for example wise as a gas barrier, a polyamide or aluminum layer usually in conjunction with another thermoplastic layer towards the paper. Exemplary layer structures can be:

Thermoplastic / printing layer / paper coating layer / paper base / thermoplastic / gas barrier (aluminum foil) / thermoplastic / thermoplastic,

Thermoplastic / printing layer / paper coating layer / paper support / thermoplastic / thermoplastic,

Printing layer / Thermoplastic / Paper coating layer / Paper carrier / Thermoplastic / Thermoplastic or thermoplastic / Printing layer / Paper coating layer / Paper carrier / Thermoplastic / Aluminum foil / Polyester (PET).

The preparation of such a packaging material is well known to those skilled in the art and described for example in EP-A-1 232 856, to which reference is expressly made.

The packaging material according to the invention preferably comprises a carrier made of paper or preferably cardboard onto which at least one paper coating slip layer and one printing layer, optionally one or more thermoplastic layers and optionally one or more further layers are applied. Also preferred is a packaging material in which at least one paper coating slip layer and one or more thermoplastic layers, optionally a printing layer, and optionally one or more further layers are applied to the carrier. Particularly preferred is a packaging material, on the support of which at least one paper coating slip layer and one printing layer, one or more thermoplastic layers and optionally one or more further layers are applied.

The paper carrier has a basis weight of> 40 g / m ² . Preferably, it has a basis weight of 150 to 600 g / m ² , which is summarized in German language under the term cardboard. A distinction is made between cardboard, which consists of bonded paper layers, and cardboard, which was produced as a simple layer of cellulose fibers, so-called cellulose cardboard. Particularly preferred is a paper support having a basis weight in the range of 150 to 250 g / m ² .

The paper carrier consists of uncoated paper or cardboard, which has been pretreated as usual and is referred to in this application as a raw paper or cardboard. The production of raw paper or cardboard is well known and usually takes place in a process in which preferably sizing agent and other adjuvants to an aqueous slurry of

Cellulose fibers are added and the pulp is dewatered on a sieve with sheet formation. Common process chemicals for papermaking are Engine sizing agents, retention aids, solidifying agents such as epichlorohydrin-crosslinked polyamidoamines, polyvinylamines of average molecular weight or strength, fixatives, biocides and dyes.

For the production of paper or paperboard, preferably sized paper or sized paperboard, one may employ any of the cellulose fibers commonly used in the paper industry, e.g. Fibers of wood pulp and all annual plants. Wood pulp is understood to mean, for example, groundwood, thermomechanical pulp (TMP), chemothermomechanical pulp (CTMP), pressure groundwood, semichemical 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 include sulphate, sulphite and soda pulps. Preferably, unbleached pulps, also referred to as unbleached kraft pulp, are used. The fibers can be used alone or mixed with each other.

In the sizing of paper or board, the sizing takes place during the manufacturing process of these materials by adding a so-called engine sizing agent to the paper stock and draining it on the wire of a paper machine with sheet formation. For the size sizing of paper or board, for example, 0.1 to 2.0, preferably 0.2 to 0.75,% by weight of polymer sizing agent (ie 100% polymer), based on dry paper product, is used. Conventional compositions are aqueous dispersions of reactive sizes such as alkyl trimers, C ₅ to C ₂₂ alkyl and / or C ₅ to C ₂₂ alkenylsuccinic anhydrides, chloroformates and C ₁₂ to C ₃₆ alkyl isocyanates, combinations of resin size and Alum, combinations of reaction products of Harzleim with carboxylic anhydrides and alum and sizing acting polymer dispersions. Instead of alum or in combination with alum, it is possible to use other aluminum-containing compounds such as polyaluminum chlorides or the polyaluminum compounds known from EP-B-1 091 043. 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 with the aid of a size press or by spraying them onto the surface of the paper.

The dewatering of the stock takes place in the presence of a retention agent. In addition to anionic retention aids or nonionic retention aids such as polyacrylic amides, preference is given to using cationic polymers as retention aids and as drainage aids. As cationic retention agents one can use all commercially available products.

Paperboard is usually made by dewatering a slurry of cellulosic fibers. Preference is given to the use of kraft pulp. Of particular interest is the use of TMP and CTMP. In the production of the paper and paperboard products to be used according to the invention, it is possible to use other adjuvants usually considered, for example fixing agents, dyes, bactericides and dry and / or wet strength agents for paper.

The microcapsules used according to the invention may be part of the applied layers selected from the paper coating slip layer, the printing layer and / or the polyethylene layer or applied as an independent microcapsule layer. According to a preferred variant, in addition to one or more of these layers, the paper or cardboard carrier also contains microencapsulated latent heat storage material. In this case, the microcapsules may be admixed with the pulp, the stock suspension in the head box or may be added to the surface sizing agent.

In a preferred embodiment, the microencapsulated

Contain latent heat storage material in the paper coating composition layer. There are one or more coating layers (eg, precoat, middle line and topcoat, also referred to as topcoat), each of which may contain microcapsules.

Paper coatings are well known. They usually consist of a) pigment and / or filler b) binders and optionally cobinders, c) optionally a thickener, d) optionally a fluorescent or phosphorescent, especially as an optical brightener, e) optionally one or more additional additives such Curing agents, defoamers, shading dyes, wetting agents, hydrophobizing agents, leveling agents, cationic additives, OBA (Optical Brideness Agent) -Carriem (PVA and starch derivatives) together.

Such a coating composition can be modified according to a variant of the invention such that a part of the filler or of the polymeric binder is replaced by microencapsulated latent heat storage materials. According to another variant of the invention, the capsules can be added to customary paper coating slips. A preferred composition contains a) pigment and / or filler

b) 1 to 40 parts by weight of binder and optionally cobinders (together as

Solid) c) 0-5 parts by weight of thickener (calculated as solid) d) 0-5 parts by weight of fluorescent or phosphorescent (calculated as

Solids) e) 0-10 parts by weight of additional additives (calculated as solids) f) 10 - 500 parts by weight of microencapsulated latent heat storage material

based on 100 parts by weight of the total amount of the pigments and fillers (a).

Such paper coating slips are also part of the present invention.

The binders and cobinders (b) are synthetically produced or naturally derived substances.

The synthetic binders and cobinders are preferably free-radically polymerized polymers which preferably consist overall of at least 30% by weight, more preferably at least 50% by weight, of the main monomers listed below.

Suitable principal monomers are selected from C ₁ to C ₆ alkyl (meth) acrylates, vinylaromatics having up hydrogens to 20 carbon atoms, vinyl esters of carboxylic acids having 1 to 20 carbon atoms, vinyl halides, ethylenically unsaturated nitriles, nonaromatic Kohlen¬ with one or two conjugated double bonds or mixtures of these monomers. Examples which may be mentioned are (meth) acrylic acid alkyl esters having a C ₁ -C ₁₀ -alkyl radical, such as methyl methacrylate, methyl acrylate, n-butyl acrylate, ethyl acrylate and 2-ethylhexyl acrylate.

In particular, mixtures of (meth) acrylic acid alkyl esters are also suitable.

As vinyl esters of carboxylic acids having 1 to 20 carbon atoms, e.g. Vinyl laurate, stearate, vinyl propionate and vinyl acetate.

Suitable vinylaromatic compounds having up to 20 carbon atoms are vinyltoluene, α-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene and preferably styrene. Examples of ethylenically unsaturated nitriles are acrylonitrile and methacrylonitrile.

Vinyl halides are chloro, fluoro or bromo substituted ethylenically unsaturated compounds, preferably vinyl chloride and vinylidene chloride.

Non-aromatic hydrocarbons having one or two conjugated olefinic double bonds may be mentioned butadiene, isoprene and chloroprene, as well as ethylene.

These are generally C 1 -C 4 -alkyl (meth) acrylates or mixtures thereof with vinylaromatics, in particular styrene, or alternatively nonaromatic hydrocarbons having two conjugated double bonds, _{, ß}

16 in particular butadiene, or mixtures thereof with vinyl aromatics, in particular styrene.

Besides the main monomers, the binder may contain other monomers, e.g. Hydroxyl-containing monomers, such as hydroxyalkyl acrylates or monomers having alkoxy groups, as obtainable by alkoxylation of hydroxyl-containing monomers with alkoxides, in particular ethylene oxide or propylene oxide, monomers having acid or anhydride groups or salts thereof, e.g. (Meth) acrylic acid, maleic acid, vinylsulfonic acid.

In addition to these described polymers, partially or completely hydrolyzed polyvinyl alcohols having different average molar masses are also used as synthetic binders in minor amounts.

Suitable natural binders and cobinders are starch (oxidized or enzymatically degraded corn, potato or wheat starch), casein and soy protein.

The preparation of the binder can according to the generally known method of emulsion polymerization carried out, usually in the presence of a union wasserlös¬ initiator, a protective colloid and emulsifiers at preferably 30 to 14O ⁰ C.

Examples of suitable initiators are sodium, potassium and ammonium persulfate, tert-butyl hydroperoxides, water-soluble azo compounds or also redox initiators, such as H ₂ O ₂ / ascorbic acid.

Suitable protective colloids and emulsifiers are e.g. Alkali salts of longer-chain fatty acids, alkyl sulfates, alkyl sulfonates, alkylated aryl sulfonates, alkylated biphenyl ether sulfonates, longer-chain fatty alcohols and the corresponding alkoxylated products of the sulfates, sulfonates and alcohols mentioned.

Preferably, the binder is at least 20 wt .-% of the Hauptmono¬ mers, more preferably at least 35 wt .-% and most preferably at least 50 wt .-%.

It has proved to be advantageous to combine binders of different composition (binders and cobinders), as described in EP 14904.

As thickener c) come in addition to widespread synthetic polymers on acrylic ester and urethane-based conventional organic and inorganic thickeners such as Carboxymethylcellulose (CMC), hydroxyethylcellulose (HEC), alginates and Schicht¬ silicates such as bentonite into consideration.

The pigment or filler (a) is generally synthetic or natural mineral white pigments, e.g. natural calcium carbonate (chalk, limestone, marble), kaolin, talc, titanium dioxide, aluminum hydroxide, zinc oxide, satin white, barium sulfate, synthetic calcium carbonate (PCC), polymer pigments, micronized silicates.

The present invention further relates to a process for producing the packaging material according to the invention by applying a paper pulp comprising microencapsulated latent heat storage material.

The paper coating slip can be applied by conventional methods to the papers to be coated (see Ullmann's Encyclopadie der Technischen Chemie, 4th Edition, Vol. 17, pp. 603 ff). The coating of the paper carrier can be carried out by applying a formulation of the above ingredients uniformly on the surface of the carrier using a doctor blade, a roller, a rod or a brush. Preferred coating apparatuses include air brushes or reverse gravure rollers or other commercially available blade or roller application systems, as well as size presses or curtain coater. Following the application of the dispersion usually follows a drying process, for example in heated channels. The drying temperatures are usually above 50 ⁰ C _{1 is} preferably from 100 to 180 ⁰ C.

In addition to the commonly used application methods (for example brushing, doctoring or spraying), a foam application is also possible. The paper coating composition is mechanically foamed, applied to the substrate and the foam dried. By a foam application, the order amount can be increased to about 200-300 g / m ² , with a corresponding increase in the layer thickness.

The paper carrier can already be used as coated paper in the production process of the packaging material. This means that in this case the paper coating composition layer is already applied at an earlier point in time and not just during the production process of the packaging material.

According to a further preferred embodiment, the microencapsulated latent heat storage material is applied as a microcapsule dispersion. Such a dispersion comprises one or more binders, optionally a thickener, optionally one or more additional additives such as defoamers, wetting agents, hydrophobizing agents, leveling agents, cationic additives, biocides and dyes, optionally mineral fillers such as CaCO ₃ , kaolin, talc, Zirconium salts to improve the blocking performance, optionally (in the case of foam application) foaming agents and foam stabilizers.

As binders, the binders listed under the paper coating compositions are suitable. Likewise, the above thickeners are preferred. If mineral fillers are added, their proportion is <20% by weight, based on the overall formulation. The application is carried out as described for the paper stroke.

A preferred composition contains:

20-80 parts by weight preferably 30-70, particularly preferably 40-60 parts by weight of microencapsulated latent heat storage material 20-80 parts by wt. Preferably 30-70, particularly preferably 40-60 parts by wt

Binder 0-5 parts by weight preferably 0-1 parts by weight thickener

0-10 parts by weight preferably 0-2 parts by weight of additional additives and 0-20 parts by weight of filler.

According to a further preferred embodiment, the microencapsulated latent heat storage material is contained in the print layer. The printing inks containing latent heat storage medium according to the invention may be liquid printing inks such as, for example, flexographic, gravure or screen printing inks, or they may be pasty inks, for example for offset or letterpress printing. In addition to the microencapsulated latent heat storage material, the printing inks comprise colorants, at least one solvent or a solvent mixture, at least one polymeric binder and optionally further additives. It may be both inks which dry by repelling and / or evaporating the solvent, by oxidatively drying or by further mechanisms drying colors or UV-curable inks. The terms "pasty inks" and liquid inks "are known in the art. Liquid printing inks contain comparatively low-viscosity and low-boiling solvents, while pasty printing inks contain comparatively high-viscosity and high-boiling solvents. Further details on the classification of printing inks are disclosed, for example, in Rompps-Lexikon "Lacke und Druckfarben", Thieme-Verlag, Stuttgart, 1998, p. 157 et seq. (In particular pages 159/160, tables 4 and 5 and illustration on page 160) ).

In the case of liquid printing inks / lacquers containing microencapsulated latent heat storage material, the amount of microcapsules according to the invention is 5 to 80% by weight with respect to the sum of all constituents of the printing ink. Preference is given to using from 20 to 75% by weight, more preferably from 30 to 75% by weight, and for example from 55 to 70% by weight. In the case of pasty printing inks or lacquers containing microencapsulated latent heat storage, the amount of microcapsules according to the invention is 5 to 60% by weight with respect to the sum of all constituents of the printing ink. Preference is given to using from 15 to 50% by weight, particularly preferably from 20 to 40% by weight.

The colorants which can be used are the usual dyes for printing inks, in particular conventional pigments. Examples are inorganic pigments such as, for example, titanium dioxide pigments or iron oxide pigments, interference pigments, carbon blacks, metal powders such as, in particular, aluminum, brass or copper powder, and also organic pigments such as azo, phthalocyanine or isoindoline pigments. It is of course also possible to use mixtures of different dyes or colorants. It is also possible to use soluble organic dyes. The amount of coloring agent is usually 5 to 25% by weight with respect to the sum of all the constituents of the printing ink. Print varnishes usually contain little or no colorants, but can be used as a base for color production.

Solvents or solvent mixture serve u.a. for dissolving the binders, but also for adjusting important application properties of the printing inks, for example the viscosity or the drying rate. The type of solvent depends on the particular intended use of the printing ink and is selected accordingly by the person skilled in the art.

Solvents or components of solvent mixtures for pasty printing inks comprise in particular high-boiling mineral oils or vegetable oils such as soybean oil. The boiling point is usually not less than 230 ⁰ C, but may also be more than 300 ⁰ C.

Solvents used for liquid printing inks such as flexographic and gravure inks include, in particular, low-boiling solvents. The boiling point is in the

Normally not more than 140 ^° C. Screen printing inks are formulated similarly to flexographic or gravure printing inks, they are merely slightly more viscous and usually have solvents with slightly higher boiling points. Examples of suitable solvents for liquid printing inks include ethanol, 1-propanol or 2-propanol, substituted alcohols such as ethoxypropanol or esters such as ethyl acetate, isopropyl acetate, n-propyl or n-butyl acetate. It is of course also possible to use mixtures of different solvents. For example, it may be a mixture of ethanol and esters such as ethyl acetate or propyl acetate. For printing with flexographic printing plates, it is regularly recommended that the proportion of esters in the total solvent does not exceed approx. 20-25% by weight. As solvents for liquid printing inks, preference is also given to using water or predominantly aqueous solvent mixtures. Depending on the type of ink usually 10 to 55 wt.% Solvents are used in terms of the sum of all components.

Radiation-curable inks generally do not contain the abovementioned solvents, but reactive diluents. Reactive diluents typically perform a dual function. On the one hand, they serve to crosslink or harden the ink, on the other hand, they also serve as conventional solvents for adjusting the viscosity. Examples include butyl acrylate, (2-ethylhexyl) acrylate, and in particular polyfunctional acrylates such as 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate or trimethylolpropane tri (meth) acrylate.

In principle, binders which are customary for liquid printing inks and pasty printing inks can be used as binders for the printing inks containing the microcapsules according to the invention. Depending on the desired application and the desired properties, the skilled person will make a suitable choice. Examples of suitable binders include polyesters, polyamides, PVC copolymers, aliphatic and aromatic ketone resins, melamine-urea resins, melamine-formaldehyde resins, maleinates, rosin derivatives, casein derivatives, ethylcellulose, nitrocellulose or aromatic or aliphatic polyurethanes. It is also possible to use polymers or copolymers of vinyl acetate, vinyl alcohol, acrylates, methacrylates, vinylpyrolidone or vinyl acetals. It is particularly advantageous to use hyperbranched polymers having functional groups, for example hyperbranched polyurethanes, polyureas or polyesteramides, as disclosed by WO 02/36695 and WO 02/36697. It is of course also possible to use mixtures of different polymeric binders, provided that the selected binders have no undesired properties in combination with one another. The amount of all binders is usually 5 to 20% by weight, based on the sum of all constituents of the printing ink.

Particularly preferred binders for liquid printing inks include, for example, nitrocellulose, ethylcellulose, hydroxyethylcellulose and also aliphatic and aromatic polyurethanes and polyureas, in particular hyperbranched polyurethanes and polyureas and mixtures thereof.

Copolymers based on (meth) acrylic acid and / or esters thereof with styrene are particularly suitable as binders for water-dilutable microencapsulated latent heat storage-containing printing inks. Such binders are commercially available as solutions or dispersions for use in inks, for example, under the name of Zinpol ^® (Fa. Worlee). Other examples include aromatic or aliphatic aqueous polyurethanes, polyesters and aqueous polyamides.

Binders preferred for pasty inks include, for example, rosins or modified rosins. Examples of modified rosin resins comprise, with polyols such as, for example, glycerol or pentaerythritol, completely or partially esterified rosin resins.

Radiation curable inks include binders comprising crosslinkable groups, such as olefinic groups, vinyl ether or epoxide groups.

The novel microencapsulated latent heat storage ink containing printing inks may further comprise one or more auxiliaries or additives. Examples of additives and auxiliaries are fillers such as calcium carbonate, alumina hydrate or aluminum or magnesium silicate. Waxes increase the abrasion resistance and serve to increase the lubricity. Examples are in particular polyethylene waxes, oxidized polyethylene waxes, petroleum waxes or ceresin waxes. Fatty acid amides can be used to increase the surface smoothness. Plasticizers serve to increase the elasticity of the dried film. For radiation-curable printing inks, at least one photoinitiator or a photoinitiator system is furthermore used as additive. For the formulation of low viscosity microencapsulated latent heat storage containing inks, such as flexographic, gravure or screen inks, the addition of anti-settling agents is usually recommended, although not always essential. The total amount of all additives and auxiliaries should usually not exceed 20% by weight with respect to the sum of all constituents of the printing ink and is preferably 0.1-10% by weight.

The preparation of the microencapsulated latent heat storage material containing printing inks according to the invention can be carried out in a manner known in principle by intensive mixing or dispersion of the components in conventional apparatus such as dissolvers or agitators.

The present invention further relates to a method for producing the packaging material according to the invention by applying a printing layer with a printing ink, the microencapsulated latent heat storage material, a colorant, a solvent or solvent mixture, at least one polymeric binder, and optionally further additives.

According to a likewise preferred embodiment, the microencapsulated

Latent heat storage contained in the thermoplastic layer. Suitable thermoplastic materials which are generally used as films are LDPE (Low Density Polyethylene), HDPE (high density polyethylene), PP (polypropylene) and PET (polyethylene terephthalate). Preference is given to using polyethylene, in particular LDPE. Suitable LDPE is described in detail on pages 7 and 8 of EP-A-1 232 856, which is incorporated herein by reference.

The thickness of the various thermoplastic layers of the packaging material is not essential. The usual thicknesses in the packaging industry can be selected.

The present invention further relates to a thermoplastic layer comprising microencapsulated latent heat storage material and to a process for producing a packaging material according to the invention by applying a thermoplastic layer comprising microencapsulated latent heat storage material. The skilled artisan distinguishes two different application methods. In the extrusion coating, the thermoplastic layer is extruded onto the respective layer, wherein the thermoplastic is pressed by the action of heat and pressure above its melting temperature with the carrier or already coated carrier to form a composite. If, on the other hand, two layers are to be "glued" together, as it were, then this is called lamination, where an adhesive layer, likewise a thermoplastic, is extruded between the two layers to be bonded.

The microencapsulated latent heat storage material may be both a component of the thermoplastic film and the thermoplastic film.

The packaging material according to the invention shows very good temperature-stabilizing properties. Breaks in the cold chain are absorbed well by the material, so that only minor changes in the temperature of the goods occur. It is therefore ideal as a packaging material for food.

The following examples are intended to explain the invention in more detail.

Unless stated otherwise, a microcapsule powder was used, as obtained according to Example 1 of DE 101 63 162 and subsequent spray drying. The microcapsules had a mean diameter of 7.8 microns. The used

Latent heat storage material or its melting point is specified separately in each experiment. example 1

Producing the packaging material by coating cardboard with an inventive microcapsule-binder dispersion (mp. Of paraffin wax core 24-26 ⁰ C)

A coating composition was prepared from the following constituents:

60 parts by weight of microcapsule powder having a particle size of 5-20 microns and a

Paraffin wax core (mp. 24-26 ⁰ C) 40 parts by weight (calculated as solids) Epotal ^® D 600, styrene-butadiene dispersion

(BASF Aktiengesellschaft), solids content 49-51% about 0.2 parts by weight Sterocoü FD ^®, thickeners based on acrylates (BASF

joint-stock company

Sterocoll FD was adjusted to about pH 9 with ammonia (100 parts by weight Sterocoll FD liquid, 150 parts by weight water, 10 parts by weight ammonia conc.) And added dropwise to the dispersion of microcapsules and epotal until the target viscosity was reached. The coating composition had a solids content of 42% by weight and a viscosity of 4300 mPas (Epprecht Rheometer Type SVT, spindle 4). ^'

The coating composition was applied by means of a spiral blade on commercial paperboard with a basis weight of 162 g / m ² and dried at 125 ⁰ C for 2 min. The application weight was 40-45 g / m ² , calculated as dry weight.

Example 2

Producing the packaging material by coating cardboard with the microcapsule-binder dispersion (mp. The paraffin wax core 28 ⁰ C)

A coating composition was prepared from the following constituents:

Paraffin wax core (mp. 28 ⁰ C) 40 parts by weight (calculated as solids) Epotal D 600, styrene-butadiene dispersion,

Solids content 49-51% 0.2 parts by weight Sterocoll FD, thickener based on acrylates

Sterocoll FD was adjusted to a pH of about 9 with ammonia (100 parts by weight Sterocoll FD liquid, 150 parts by weight water, 10 parts by weight ammonia conc.) And added dropwise to the microcapsule / epotal dispersion until the target viscosity is reached. The coating composition had a solids content of 42% by weight and a viscosity of 3200 mPas (Epprecht Rheometer Type SVT, spindle 4). The coating composition was applied by means of a wire-wound rod to commercially available cardboard with a weight per unit area of 162 g / m ² and dried at 125 ^° C. for 2 minutes. The application weight was 40-45 g / m ² , calculated as dry weight.

Example 3

Coating of cardboard with a paper coating, the microencapsulated

Contains latent heat storage material

A paper coating slip was prepared from the following components:

65 parts by weight of microcapsule powder having a mean particle size of 6.5 microns and a core of techn. n-tetradecane, about 94%, mp 6 ⁰ C 30 parts by wt of the pigment Hydrocarb ^® 90 slurry (ger. as a solid), finely divided chalk from Omya GmbH

5 parts by weight of the pigment Amazon Plus slurry (ger. As a solid), a finely divided

Clay of Kaolin International BV 10 parts Styronal ^® PR 8780 X (eng. As solid), polymer dispersion based on

Styrene / butadiene (from BASF Aktiengesellschaft) 0.2 parts by weight Sterocoll FD, thickener based on acrylates

The paper coating slip had a solids content of 54.8% by weight, a pH of 8.8 and a viscosity of 1374 mPas (100 rpm) according to Brookfield DV-II +, spindle 4, and 59.79 mPas (at 40,000 1 / s) and 85.59 mPas (at 63000 1 / s) according to Rheostress 600 from Thermo-Haake.

The substrates used were a kraft paper having a weight per unit area of 186 g / m ² , a green cardboard having a basis weight of 200 g / m ² and aluminum-coated cardboard. The application of the paper coating slip took place on one side with 50 g / m ² on a laboratory coater (application method: roller, metering method: blade). The drying took place with an IR emitter.

A special paper for coating, satined, wood-free, white, bleached, fully sized, raw weight 70-80 g / m ^{2 was} coated analogously to the raw cardboard.

Example 4

A paper coating slip was prepared from the following components:

65 parts by weight of microcapsule powder having an average particle size of 6.2 μm and a core n-dodecane; Mp -10 ⁰ C 30 parts by weight Hydrocarb. 90 slurry (eng. As solid) 5 parts by weight of Amazon Plus slurry (solid as a solid) 10 parts by weight of Styronal PR 8780 X (solid as a solid) 0.2 part by weight of Sterocoll FD, thickener based on acrylates

The paper coating had a solids content of 53.1 wt .-%, a pH of 8.7 and a viscosity of 1592 mPas (100 rpm) according to Brookfield DV-II +, spindle 4bzw. 62.73 mPas (at 40000 1 / s) and 43.90 mPas (at 63000 1 / s) according to Rheostress 600 from Thermo-Haake.

The substrates used were a kraft paper having a weight per unit area of 186 g / m ² , a green cardboard having a basis weight of 200 g / m ² and aluminum-coated cardboard. The paper coating slip was applied on one side at 50 g / m ² on a laboratory coater (application method: roller; The drying took place with an IR emitter.

Example 5

Foam coating (microcapsule binder dispersion)

A coating agent was prepared from the following constituents:

100 parts by weight aqueous acrylic dispersion FG 50% (Acronal ^® A 420 S; BASF Aktiengesellschaft

40 parts by weight of water

0.6 parts by weight of ammonia 25% strength by weight 0.5 parts by weight of Pigment Distributor A (dispersant for pigments on

Ammonium polyacrylate base of BASF Aktiengesellschaft)

0.2 parts by weight of Helizarin Blue ^® BT

75 parts by weight of the microcapsule powder (mp. 24-26 ⁰ C)

1 part by weight of Emulphor ^® FES 30 (foaming agent from BASF Aktiengesellschaft)

7 parts by weight of ammonium stearate 35% (foam stabilizer)

2 parts by weight Latekoll D ^® (thickener based on polyacrylate BASF

joint-stock company

Properties of the coating agent: pH 8.5 - 9.5

Viscosity 23 dPas (Haake VT02, spindle 1)

The coating agent was mechanically foamed (foam density 280 g / l) and applied by means of a Spaltrockels (600 microns) on one side of the substrate.

Subsequently, the coated substrate for 1 min at 90 ⁰ C and 1 min at 120 ⁰ C. dried. The foam layer was then compressed with a calender at room temperature, with a line pressure of 40 kN.

Example 6 Coating of Cardboard by PU Foam Containing Micro-encapsulated Latenwärmespeicher Material The coating composition was prepared from the following components:

100 parts by weight Emuldur ^® DS 2360 (polymer dispersion based on polyurethane, BASF Aktiengesellschaft)

30 parts by weight of water

60 parts by weight of the microcapsule powder (mp. 24-26 ⁰ C)

10 parts by weight Siligen SIO ^® (BASF Aktiengesellschaft)

2 parts by weight Saduren ^® 163 (BASF Aktiengesellschaft) 0.5 parts by weight ammonia water, 25% strength

20 parts by weight Talc IT 20 Star

20 parts by weight of C & S Stabsol

1 part by weight Latekoll D

Properties of the coating agent: pH about 9.7

Viscosity about 12 dPas (Haake VT02, spindle 1) Solids content: about 55%

The coating composition was mechanically foamed (foam density 250 g / l) and foam-coated in each case 2 samples of a carton with a wet foam support of 0.5 and 1 mm. The mixture was then predried at 90 ^° C. for 1-2 minutes and crosslinked at 160 ^° C. for 1 minute. The fixed order is 50 or 90 g / m ² .

Claims

claims

1. Packaging material in the form of a composite comprising at least one

Carrier of paper or cardboard, on the at least one paper coating mass layer, optionally a printing layer, optionally one or more

Thermoplastic layers and optionally one or more further layers are applied, characterized in that microencapsulated latent heat storage material is contained in at least one of the auf¬ applied layers and the capsule wall of the microencapsulated latent heat storage material is constructed

10 to 100 wt .-% of one or more C ₁ -C ₂₄ alkyl esters of acrylic and / or

Methacrylic acid (monomers I),

0 to 80 wt .-% of a bi- or polyfunctional monomer (monomers II), which is insoluble or sparingly soluble in water, and

0 to 90% by weight of other monomers (monomer III)

in each case based on the total weight of the monomers.

2. Packaging material according to claim 1, characterized in that the tent¬ tentwärmespeichermaterial a lipophilic substance with a solid / liquid Pha¬ senübergang in the temperature range from -30 to +30 ⁰ C.

3. Packaging material according to claim 1 or 2, characterized in that the latent heat storage material is an aliphatic Kohlenwasserstoffverbin¬ tion.

4. Packaging material according to one of claims 1 to 3, characterized gekennzeich¬ net, that the capsule wall of the microencapsulated latent heat storage material is constructed

10 to 95 wt .-% of one or more (^^.) - Alkyl esters of acrylic and / or

Methacrylic acid (monomers I),

5 to 60 wt .-% of a bifunctional or polyfunctional monomer (monomers II), which is insoluble or sparingly soluble in water, and

0 to 50% by weight of other monomers (monomer III)

in each case based on the total weight of the monomers.

5. Packaging material according to one of claims 1 to 4, characterized gekennzeich¬ net, that the capsule wall of the microencapsulated latent heat storage material is constructed 30 to 95 wt .-% of one or more dC ₂₄ alkyl esters of acrylic and / or

Methacrylic acid (monomers I),

10 to 50 wt .-% of a bi- or polyfunctional monomer (monomers II), which is insoluble or sparingly soluble in water, and

0 to 30% by weight of other monomers (monomer III)

in each case based on the total weight of the monomers.

6. Packaging material according to one of claims 1 to 5, characterized gekennzeich¬ net that 5 to 300 g / m ² micro-encapsulated latent heat storage material auf¬ wear.

7. Packaging material according to one of claims 1 to 6, characterized marked, that on the carrier at least one paper coating slip layer and a

Printing layer, optionally one or more thermoplastic layers and optionally one or more further layers are applied.

8. Packaging material according to one of claims 1 to 6, characterized marked, that on the support at least one paper coating slip layer and one or more thermoplastic layers, optionally a printing layer, and optionally one or more further layers are applied.

9. Packaging material according to one of claims 1 to 6, characterized marked, that on the carrier at least one paper coating slip layer and a

Printing layer, one or more thermoplastic layers and optionally ei¬ ne or more further layers are applied.

10. Packaging material according to one of claims 1 to 9, characterized marked, that the microencapsulated latent heat storage material in addition to the micro-capsule-containing layer is also contained in the carrier made of paper or cardboard.

11. Packaging material according to one of claims 1 to 10, characterized in that the microencapsulated latent heat storage material is contained in the paper coating slip layer.

12. Packaging material according to one of claims 1 to 10, characterized gekenn¬ characterized in that the paper coating slip pigment and / or filler (a),

b) 1 to 40 parts by weight of binder and, if appropriate, cobindent (calculated together as solid) c) 0 to 5 parts by weight of thickener (calculated as solids) d) 0 to 5 parts by weight of fluorescent or phosphorescent dye (calculated as solid), e) 0 to 10 parts by weight of additional additives (calculated as solids) and f) contains 10 to 500 parts by weight of microencapsulated latent heat storage material,

13. paper coating composition containing pigment and / or filler

b) 1 to 40 parts by weight of binder and, if appropriate, cobinders (total calculated as solids) c) 0 to 5 parts by weight of thickener (calculated as solids) d) 0 to 5 parts by weight of fluorescent or phosphorescent dye ( calculated as solids), e) 0-10 parts by weight of additional additives (calculated as solids) f) contains 10 to 500 parts by weight of microencapsulated latent heat storage material,

14. A method for producing a packaging material according to claim 1, characterized da¬, that applying a paper coating slip comprising microencapsulated latent heat storage material.

15. Packaging material according to one of claims 1 to 7, 9 or 10, characterized in that the microencapsulated latent heat storage material is contained in the printing layer.

16. Packaging material according to claim 15, characterized in that the printing layer is obtained by applying a printing ink and the printing ink comprises a colorant, microencapsulated latent heat storage material, a solvent or solvent mixture, at least one polymeric binder, and optionally further additives.

17. Printing ink, comprising a colorant, microencapsulated latent heat storage material, a solvent or solvent mixture, at least one polymeric binder, and optionally further additives.

18. A process for the preparation of a packaging material according to claim 1, characterized in that one brings auf¬ a printing layer with a printing ink, a colorant, microencapsulated latent heat storage material, a Solvent or solvent mixture, at least one polymeric binder, and optionally further additives.

19. Packaging material according to one of claims 1 to 6, characterized marked, that the microencapsulated latent heat storage material is contained in the Thermo¬ plastic layer.

20. A thermoplastic layer comprising a thermoplastic and microencapsulated latent heat storage material.

21. A method for producing a packaging material according to claim 1, da¬ characterized in that applying a thermoplastic layer comprising microencapsulated latent heat storage material.

22. Use of the packaging material according to claim 1 for packaging food.