WO2009090154A1 - Use of solid polyvinyl ester resins in printing inks - Google Patents

Abstract

The invention relates to the use of inks for printing polymer substrates. Said printing inks contain one or more cellulose derivatives, one or more coloring agents, organic solvents, and other optional additives and are characterized in that the same additionally contain one or more solid polyvinyl ester resins based on: a) one or more vinyl esters, b) one or more optional hydrophilic monomers, and c) one or more optional hydrophobic monomers, the percentages by weight relating to the total weight of the solid polyvinyl ester resins. The invention also relates to solid polyvinyl acetate resins which can be obtained by means of radically initiated polymerization of vinyl acetate, one or more hydroxy-functional methacrylic esters or acrylic esters of alcohols comprising 1 to 15 C atoms, and one or more other optional monomers, and which are characterized in that a) 90 to 99.9 percent by weight of vinyl acetate and ß) 0.1 to 10 percent by weight of one or more hydroxy-functional methacrylic esters or acrylic esters of alcohols comprising 1 to 15 C atoms are copolymerized, the added percentages by weight amounting to a total of 100 percent by weight.

Description

Use of polyvinyl ester solid resins in printing inks

The invention relates to the use of solid polyvinyl ester resins in printing inks for printing on polymer substrates, the so-available printed polymer substrates and printed composites of a plurality of polymer substrates and solid polyvinyl acetate resins and methods for producing the solid polyvinyl acetate resins.

Printing inks usually contain polymeric binders, solvents and pigments or dyes and are applied to polymer substrates, for example by the flexographic or gravure printing method. In this way, printed polymer substrates can be produced which carry single or multi-colored texts, pictorial representations or ornaments as imprints.

Cellulose derivatives such as cellulose nitrates, cellulose acetates, cellulose propionate (CP) or cellulose acetobutyrate (CAB) are frequently used as polymeric binders for printing inks. Cellulose nitrate, also known as nitrocellulose, is the most common. Advantages of cellulose nitrate are excellent solvent release, good pigment dispersion, high blocking stability and good compatibility with many common resins and additives. Moreover, cellulose nitrate is available on the market at economically favorable conditions.

The application requirements for printing inks for printing on polymer substrates, such as plastic films or plastic packaging material, are becoming ever higher. Thus, a strong adhesive strength of the applied printing inks on the polymer substrates and a high flexibility of the printed polymer substrates is increasingly required.

In order to achieve sufficient adhesion to polymer substrates, low molecular weight adhesion promoters are usually added to printing inks based on cellulose derivatives. Thus, DE-A 3525925 recommends the addition of special organ Notitanaten as a primer for cellulose nitrate-based inks, which may be additionally modified with polyurethanes or polyamides. Unfortunately, organotitanates are often not compatible with the other formulation ingredients of printing inks.

As a further additive, printing inks based on cellulose nitrate often contain low molecular weight plasticizers in order to improve the flexibility or flexural strength of the print or to reduce the brittleness of the print. Common low molecular weight plasticizers are dibutyl phthalate, dioctyl phthalate and tricresyl phosphate. However, the dosage of plasticizers in the particular ink formulation is critical because too little plasticizer eventually leads to a brittle print with poor adhesion to the polymer substrates. However, the use of too large an amount of plasticizers increases the blocking tendency of the printing inks. In addition, plasticizers tend to migrate from the printed polymer substrates or the printed composites, which is problematical in particular in their use in the food sector.

The printed polymer substrates are increasingly being processed into printed composites. For this purpose, one or more further polymer substrates are applied to the printed surface of polymer substrates by means of lamination or extrusion. This has the advantage, for example, that the product packaged with a corresponding printed composite does not come into direct contact with the imprint. In addition, special optical effects can be achieved with composites. However, especially with printed composites, a strong adhesive strength between the individual polymer substrates and the imprinting is of particular importance.

Particular problems are encountered in achieving a high bond strength of the imprint on critical polymer substrates, such as, for example, polyethylene (PE), polypropylene (PP) or polyvinyl chloride (PVC), without the addition of further resins, low molecular weight plasticizers or adhesion promoters may be added.

Against this background, the object was to provide printing inks based on cellulose derivatives for printing on polymer substrates, in particular of critical polymer substrates, such as polyethylene (PE), polypropylene (PP) or polyvinyl chloride (PVC), with which flexible, not brittle printed polymer substrates or printed composites are obtained, which should be characterized by strong adhesive strengths between the imprint and the polymer or the polymer substrates, so that ideally can be dispensed with the addition of low molecular weight adhesion promoters or plasticizers completely.

Surprisingly, this object was achieved by the addition of polyvinyl ester solid resins to printing inks based on cellulose derivatives.

Cellulose derivatives are used in a variety of applications and in different formulations. Thus, for example, GB 369260 describes color formulations containing cellulose nitrate and polyvinyl acetate as lacquers for the coating of leather, resulting in products with a particular luster. DE-A 709395 describes color photographic films which contain, as an adhesion-promoting layer between the cellulose ester-based carrier and the light-sensitive material, a formulation of cellulose nitrate and, for example, polyvinyl acetate. GB 525671 describes processes for coating rubber articles, in which the rubber surface is first coated with an aqueous polyvinyl alcohol-stabilized polyvinyl acetate emulsion and then overcoated with, for example, a cellulose nitrate-based coating formulation. GB 562098 describes protective coatings for wooden aircraft propellers by applying a thermoplastic primer and a thermally crosslinking topcoat. The thermoplastic primer preferably consists of a mixture of cellulose nitrate and polyvinyl acetate. The finished coating is characterized by a high mechanical stability. GB 597425 describes processes for producing luminescent coatings, in which a fluorescent powder in a binder of cellulose nitrate and polyvinyl acetate is applied to the fluorescent tubes and the binders are subsequently removed by thermal decomposition. The addition of polyvinyl acetate is advantageous for the production of homogeneous and less water-sensitive layers. No. 3,197,325 describes primers for wood floors based on polyvinyl acetate and nitrocellulose. Ru 2278024 describes the coloring of wood with mixtures of aqueous polyvinyl acetate dispersions and nitrocellulose pieces.

To modify cellulose nitrate, it is also common to use alkyd, ketone or acrylate resins or polyamides or polyurethanes. An overview of corresponding formulations for a wide variety of applications can be found in "Ullmann's Encyclopedia of Industrial Chemistry - Release 2007", 7 ^th Edition, Section 2.2.1.1.

DE-A 1520416 describes terpolymers based on vinyl acetate, acrylic acid hydroxyalkyl esters and crotonic acid and vinyl acetate-hydroxyacrylic acid alkyl ester copolymers having a content of vinyl acetate of less than 40% by weight and their conversion into polyvinyl alcohols for use as coating compositions. medium. US 3208963 describes processes for the preparation of terpolymers based on vinyl acetate, hydroxyalkyl acrylate and crotonic acid or Crotonsäurealkylestern and vinyl acetate-Hydroxyacrylsäurealkylester copolymers having a vinyl acetate content of 90 mol%. US Pat. No. 3,532,708 describes crosslinkable polymer compositions which may contain copolymers of vinyl acetate and hydroxyalkyl (meth) acrylates, the content of vinyl acetate being less than 55% by weight.

The invention relates to the use of printing inks for printing on polymer substrates, the inks comprising one or more cellulose derivatives, one or more colorants, contain organic solvents and optionally further Zusatzstof ^¬ fe, characterized in that additionally one or more polyvinyl ester solid resins based on a) one or more vinyl esters, optionally b) one or more hydrophilic monomers and optionally c) one or more hydrophobic monomers , where the data in wt .-% on the total weight of the polyvinyl ester solid resin relate.

In the production of solid polyvinyl ester resins by means of radi ^¬ lisch initiated polymerization are as Vinylester a) preferably one or more Vinylester of unbranched or branched carboxylic acids having 2 to 15 carbon atoms are used.

Examples of preferred Vinylester are vinyl acetate, isopropyl penylacetat (IPAC), vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate, 1-methylvinyl acetate, vinyl pivalate and Vinylester of CC-branched monocarboxylic acids having 5 to 13 carbon atoms, for example VeoVa9 ^R or VeoValO ^R (trade name of the company Shell). Particularly preferred are vinyl acetate, Veo- VA9 ^R VeoValO ^R, isopropenyl acetate (IPAC), vinyl pivalate and Vi ^¬ laurate. Most preferred is vinyl acetate.

Preferably ≥ 40 wt .-% Vinylester a) are used, be ^¬ Sonders preferably 70 to 100 wt .-% and most preferably 70 to 99.9 wt .-%, each based on the total weight of solid polyvinyl ester resin.

Preferred hydrophilic monomers b) are selected from the group consisting of hydroxy or amino-functional methacrylic esters and acrylic esters of alcohols having 1 to 15 carbon atoms, ethylenically unsaturated mono- and dicarboxylic acids or their anhydrides, ethylenically unsaturated carboxylic acid amides and Cabonsäurenitrile, monoesters of Fumaric acid and maleic acid and ethylenically unsaturated sulfonic acids. Particularly preferred hydrophilic monomers b) are substituted or unsubstituted tuierte hydroxy or amino-alkyl methacrylate or - acrylic acid esters of alcohols having 1 to 15 carbon atoms.

Examples of preferred hydrophilic monomers b) are hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate, crotonic acid, acrylic acid, methacrylic acid, fumaric acid, maleic acid, N-vinylformamide, acrylamide, N-vinylpyrrolidone, acrylonitrile, maleic anhydride, vinylsulfonic acid, Acrylamido-2-methyl-propanesulfonic acid and salts thereof. Examples of particularly preferred hydrophilic monomers b) are hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate and hydroxypropyl methacrylate.

Preferably, from 0 to 40% by weight of hydrophilic monomers b) are used, more preferably from 0 to 30% by weight, and most preferably from 0.1 to 10% by weight, based in each case on the total weight of the polyvinyl ester solid resin.

The hydrophobic monomers c) are preferably selected from the group comprising methacrylic acid esters and acrylic esters of alcohols having 1 to 15 carbon atoms, olefins, dienes, vinyl aromatics and vinyl halides.

Preferred methacrylic esters or acrylates are methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, n-, iso- and t-butyl acrylate, n-, iso- and t-butyl methacrylate, 2-ethylhexyl acrylate, norbornyl acrylate. Particularly preferred are methyl acrylate, methyl methacrylate, n-, iso- and t-butyl acrylate, 2-ethylhexyl acrylate and norbornyl acrylate.

Suitable dienes are 1,3-butadiene and isoprene. Examples of polymerizable olefins are ethene and propene. As vinyl aromatics styrene and vinyl toluene can be polymerized. From the group of vinyl halides usually vinyl chloride, vinylidene chloride or vinyl fluoride, preferably vinyl chloride, are used. Other suitable monomers c) are also polymerizable silanes or mercaptosilanes. Preference is given to γ-acryl or γ-methacryloxypropyltri (alkoxy) silanes, α-methacryloxymethyltri (alkoxy) silanes, γ-methacryloxypropylmethyldi (alkoxy) silanes, vinylalkyldi (alkoxy) silanes and vinyltri (alkoxy) silanes, it being possible to use, for example, methoxy, ethoxy, methoxyethylene, ethoxyethylene, methoxypropylene glycol ether or ethoxypropylene glycol ether radicals as alkoxy groups. Examples of these are vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltris (1-methoxy) isopropoxysilane, vinyltributoxysilane, vinyltriacetoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, methacryloxymethyltrimethoxysilane, 3-methacryloxypropyltris ( 2-methoxyethoxy) silane, vinyltrichlorosilane, vinylmethyldichlorosilane, vinyltris (2-methoxyethoxy) silane, trisacetoxyvinylsilane, 3- (triethoxysilyl) propylsuccinic anhydride. Also preferred are 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane and 3-mercaptopropylmethyldimethoxysilane.

Preferably, 0 to 40 wt .-% of hydrophobic monomers c) are used, more preferably 0 to 30 wt .-% and most preferably 0 to 10 wt .-%, each based on the total weight of the solid polyvinyl ester resin.

Examples of suitable homopolymers and copolymers are vinyl acetate homopolymers,

Copolymers of vinyl acetate and one or more other vinyl esters, copolymers of vinyl acetate and one or more

Hydroxy- or amino-functional methacrylic esters or acrylic esters of alcohols having 1 to 15 carbon atoms or copolymers of vinyl acetate, one or more further vinyl esters and one or more hydroxy- or amino-functional methacrylic acid esters or acrylic acid esters of alcohols having 1 to 15 carbon atoms ,

Preference is given to vinyl acetate homopolymers; Copolymers of vinyl acetate and 0.1 to 15 wt .-% of one or more vinyl esters having 1 to 12 carbon atoms in the carboxylic acid such as isopropenyl acetate, vinyl propionate, Vinyllau- rat, vinyl esters of alpha-branched carboxylic acids having 5 to 13 carbon atoms such VeoVa9R, VeoValOR, VeoVallR;

Copolymers of vinyl acetate and 0.1 to 30% by weight of one or more hydroxy- or amino-functional methacrylic esters or acrylic esters of alcohols having 1 to 15 carbon atoms, in particular hydroxyethyl acrylate; or copolymers with vinyl acetate, 0.1 to 15 wt .-% of one or more vinyl esters having 1 to 12 carbon atoms in the carboxylic acid radical, in particular isopropenyl acetate, and 0.1 to 30 wt .-% of one or more hydroxy or amino -functional methacrylic acid esters or acrylic acid esters of alcohols having 1 to 15 C atoms, in particular hydroxyethyl acrylate; wherein the polymers may each contain the monomers c) in the stated amounts, and the information in wt .-% add up to each 100 wt .-%.

Another object of the invention are polyvinyl acetate

Solid resins obtainable by free-radically initiated polymerization of vinyl acetate, one or more hydroxy-functional methacrylic acid esters or acrylic esters of alcohols having 1 to 15 C atoms and optionally one or more further monomers, characterized in that α) 90 to 99.9% by weight Vinyl acetate and β) 0.1 to 10 wt .-% of one or more hydroxy-functional methacrylic acid esters or acrylic acid esters of alcohols having 1 to 15 carbon atoms are copolymerized, wherein the data in wt .-% to 100 wt. Add%.

For the preparation of the solid polyvinyl acetate resins by means of free-radically initiated polymerization, the monomers β) which are preferred are the same or particularly preferred hydroxy-functional methacrylic acid esters or acrylic esters which are correspondingly listed for the preparation of the solid polyvinyl ester resins. As further monomers for the preparation of the solid polyvinyl acetate resins, it is possible to use one or more monomers selected from the group comprising such monomers a), b) and c), which are different from the monomers α) and β). From this group, the monomers are preferred and particularly preferred, which are also listed correspondingly for the preparation of the polyvinyl ester solid resins.

However, the solid polyvinyl acetate resins preferably contain no carboxylic acid units and particularly preferably no crotonic acid units. The polyvinyl acetate solid resins preferably also contain no units of crotonic acid derivatives, particularly preferably no units of esters of crotonic acid, such as their methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl or octyl esters.

For the preparation of the solid polyvinyl acetate resins preferably 92 to 99.9 wt .-% and particularly preferably 95 to 99.9 wt .-% vinyl acetate α) are used. The monomers β) are preferably used at 0.1 to 8 wt .-% and particularly preferably at 0.1 to 5 wt .-%. The data for vinyl acetate .alpha. And the monomers .beta.) In% by weight each relate to the total weight of the particular polyvinyl acetate solid resin.

Examples of preferred polyvinyl acetate solid resins are

Copolymers of vinyl acetate and one or more hydroxy or amino-functional methacrylic acid esters or acrylic acid esters of alcohols having 1 to 15 carbon atoms and optionally one or more further vinyl esters.

Particularly preferred are copolymers of vinyl acetate, 0.1 to 8 wt .-% of one or more hydroxy or amino-functional methacrylic acid esters or acrylic acid esters of alcohols having 1 to 15 carbon atoms, in particular hydroxyethyl acrylate, and 0.1 to 9 9% by weight of one or more vinyl esters having 1 to 12 C atoms in the carboxylic acid radical, such as isopropenyl acetate, vinyl propionate, vinyl laurate, vinyl esters of alpha-branched carboxylic acids having 5 to 13 C atoms, such as VeoVa9R, VeoValOR, VeoVallR, wherein the polymers can each contain the monomers c) in the stated amounts, and the information in wt .-% add up to 100 wt .-%.

The polyvinyl ester solid resins or the polyvinyl acetate

Solid resins preferably have a weight average molecular weight Mw of 5,000 to 500,000 g / mol, more preferably 10,000 to 150,000 g / mol, and most preferably 50,000 to 100,000 g / mol. Polyvinyl ester solid resins with molecular weights Mw of more than 500,000 g / mol usually lead to printing inks with too high a viscosity. Polyvinyl ester solid resins having a molecular weight Mw of less than 5,000 g / mol usually do not have the desired mechanical properties.

Examples of suitable cellulose derivatives are cellulose esters, such as cellulose nitrate, cellulose propionate, cellulose acetobutyrate (CAB), or cellulose ethers, such as methylcellulose, ethylcellulose or hydroxypropylmethylcellulose (HPMC). Preference is given to cellulose esters. Particularly preferred is cellulose nitrate.

For the printing inks, organic solvents or components for mixtures of several organic solvents are preferably esters, such as methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, sec-butyl acetate, isobutyl acetate, alcohols, such as ethanol, n Propanol, i-propanol, ethoxypropanol, or glycol, ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, Disiobutylketon, cyclohexanone, aliphatic or aromatic hydrocarbons, such as toluene or xylene used. Preference is given to solvent mixtures of esters and alcohols. Particularly preferred solvent mixtures are mixtures of

Ethanol and ethyl acetate or of i-propanol and propyl acetate.

Suitable colorants are all customary pigments or dyes or mixtures of pigments and dyes. The dyes are generally soluble in the organic solvents and the pigments are generally dispersible therein. The dyes have under normal conditions 23/50 according to DIN 50014 in the organic solvents preferred has a solubility of ≥ 10 g / l. The pigments preferably have a solubility of ≦ 5 g / l under normal conditions 23/50 in accordance with DIN 50014 in the organic solvents.

Suitable dyes are, for example, anthraquinone, sulfur, indigoid, triphenylmethane or phthalocyanine dyes. Suitable pigments are both inorganic and organic pigments.

Examples of suitable inorganic pigments are white pigments, such as titanium dioxide, zinc sulfide pigments or lithopones, colored pigments, such as ultramarine pigments, chrome yellow or cobalt blue, black pigments, such as carbon black or iron oxide black, or metallic effect pigments. Preferred inorganic pigments are Pigment White 6 (titanium dioxide, titanium white), Pigment Red 101 and 102, Pigment Brown 6 and 7 (iron oxide and iron silicate pigments), Pigment Blue 2.7, Pigment Black 7 (carbon black). Examples of suitable organic pigments are tetrachloroisoindolinone pigments, isoindoline pigments, phthalocyanine pigments, quinacridone pigments, perinone pigments, perylene pigments, anthraquinone pigments, triphenylmethane pigments, quinophthalone pigments, naphthol pigments, azo pigments, polycyclic pigments and arylamide yellow pigments. Examples of preferred organic pigments are Pigment Yellow 12 and 13 (diaryl yellow), Pigment Orange 34, Pigment Red 2, Pigment Red 57: 1, Pigment Red 81, Pigment Blue 15: 3 (phthalocyanine blue), Pigment Blue 56 , Pigment Green 7 (phthalocyanine green) and Pigment Violet 19.

Typical formulations for the printing inks contain from 0.1 to 20% by weight of cellulose derivatives, from 0.1 to 30% by weight of polyvinyl ester solid resin, from 0.1 to 30% by weight of colorants, from 0 to 10% by weight of additives, such as other polymers, retarders (retarders), waxes, wetting or dispersing agents, plasticizers, adhesion promoters or surface additives, and 30 to 90 wt .-% of an organic solvent or a mixture of several organic solvents, wherein the data in wt. -% of the total weight of the respective printing ink and total add up to 100 wt .-%.

Plasticizers may be contained in the printing inks to 0 to 10 wt .-%. Adhesion promoters can be present in the printing inks at 0 to 2% by weight, preferably at 0 to 1% by weight. The data for the plasticizers and the adhesion promoters in% by weight relate in each case to the total weight of the respective printing ink.

Examples of polymer substrates are polyalkylenes, polyamides, polyesters or polyvinyl halides, which are optionally metallized. Preferred polymer substrates are polyethylene terephthalate (PET), oriented polypropylene (OPP), polyethylenes (PE), polyamide (PA), polyvinylene dichloride (PVDC).

The invention further provides processes for preparing the solid polyvinyl acetate resins by free-radically initiated polymerization of vinyl acetate, one or more hydroxy-functional methacrylic acid esters or acrylic acid esters of alcohols having from 1 to 15 carbon atoms and optionally one or more further monomers in that α) 90 to 99.9% by weight of vinyl acetate and β) 0.1 to 10% by weight of one or more hydroxy-functional methacrylic acid esters or acrylic acid esters of alcohols having 1 to 15 C atoms are copolymerized add the data in wt .-% to each 100 wt .-%.

The polyvinyl ester solid resins or polyvinyl acetate solid resins are obtainable by means of free-radical substance, suspension, emulsion or solution polymerization processes of the monomers in the presence of free-radical initiators. When carrying out the solution polymerization process, preference is given to using alcohols, ketones or esters as solvents or as components for solvent mixtures. The reaction temperature is usually from 20 ⁰ C to 100 ⁰ C, preferably 40 ⁰ C to 80 ⁰ C. In general, polymerized at atmospheric pressure. The copolymerization of gaseous monomers at room temperature, such as ethylene, is carried out under pressure, generally between 1 and 100 bar.

Suitable radical initiators are oil-soluble initiators, such as t-butyl peroxy-2-ethylhexanoate, t-butyl peroxypivalate, t-butyl peroxyneodecanoate, dibenzoyl peroxide, t-amyl peroxypivalate, di (2-ethylhexyl) peroxydicarbonate, 1,1-bis (t-butyl peroxy) -3, 3, 5-trimethylcyclohexane and di (4-t-butylcyclohexyl) peroxydicarbonate. Also suitable are azo initiators such as azobisisobutyronitrile. The initiators are generally used in an amount of 0.005 to 5.0% by weight, preferably 0.1 to 2.0% by weight, based on the total monomer.

The adjustment of the molecular weight can be carried out in a known manner by addition of regulator, by the solvent content, by varying the initiator concentration and by varying the temperature. Suitable regulators are, for example, methanol, ethanol, propanol, isopropanol or acetaldehyde.

After completion of the polymerization, the residual monomer removal can be postpolymerized using known methods. Volatile residual monomers and further volatile constituents, such as solvents or regulators, can also be removed by means of distillation, preferably under reduced pressure. In the case of suspension polymerizations, this can also be done by supporting the introduction of steam (= stripping).

When using hydroxy-functional methacrylic esters or acrylates, preferably more than 75% by weight of the total amount of hydroxy-functional monomers used is metered in after initiation of the polymerization, ie during the polymerization. The other monomers can be completely or partially charged and the remaining amount of the other monomers can be added. To prepare the printing inks, it is possible to mix the cellulose derivatives, the colorants, the organic solvents, the solid polyvinyl ester resins and optionally the further additives in any desired manner. Thus, the cellulose derivatives, the polyvinyl ester solid resins and optionally the colorants can be dissolved or dispersed separately or together in an organic solvent or a mixture of organic solvents. Preferably, first solutions of the cellulose derivatives and the solid polyvinyl ester resins are prepared in an organic solvent or a mixture of organic solvents, in which subsequently one or more colorants are dissolved or dispersed. The dispersion of the pigments is carried out by customary dispersion techniques, for example using bead mills, basket mills or dissolvers.

Optionally, before, during or after the addition of organic solvents further polymeric or low molecular weight additives such as polyurethanes, retarders (retarders), waxes, wetting and dispersing agents, plasticizers, adhesion promoters or surface additives may be added.

The production of the printing inks can be carried out under normal conditions according to DIN50014 or with heating.

Another object of the invention are printed polymer substrates obtainable by applying one or more printing inks on polymer substrates and subsequent drying.

Printed polymer substrates are obtained by applying the printing inks to the polymer substrates by conventional methods and using the usual apparatus. Preferred methods are the flexographic printing method or the gravure printing method. The film thickness of the printing inks applied to polymer substrates (wet film thickness) is preferably 0.1 to 100 μm, more preferably 1 to 30 μm. Drying of the printing inks applied to the polymer substrates takes place preferably under normal conditions according to DIN50014 or with heating.

Another object of the invention are printed polymer composites, characterized in that one or more further polymer substrates are applied to a printed polymer substrate.

All customary processes for the production of polymer composites can be used for producing the printed polymer composites. For example, one or more polymer substrates may be laminated to the printed polymer substrates with common adhesives or may be melt extruded onto the printed polymer substrates.

The procedure according to the invention gives printed polymer substrates or printed polymer composites in which the imprints adhere strongly to the polymer substrates, even if printing inks containing no adhesion promoter are used. High adhesive strengths on the polymer substrates are achieved in particular when printing inks containing polyvinyl acetate solid resins with hydroxy-functional methacrylic ester or acrylic ester units are used. In particular, this applies when using polymer substrates on which printing inks generally adhere only poorly, such as on polyalkylenes, polyamides, polyesters or polyvinyl halides.

The adhesive strengths are preferably ≥ 0.6 N / 15 mm, more preferably ≥ 1 N / 15 mm, and most preferably ≥ 2

N / 15 mm characterized (determined according to DIN 53357 according to method A for "testing of plastic sheets and films, separation test of the layers").

In addition, the imprint obtainable by the use of the printing inks according to the invention is not brittle but flexible, so that it is possible to dispense with the addition of plasticizers or adhesion promoters to the printing inks. The printed poly- mersubstrate or the printed polymer composites have a uniform color image, which is due to the good compatibility and uniform mixing or dispersion of the components of the printing inks.

The following examples serve to further illustrate the invention without limiting it in any way.

Preparation of polyvinyl ester solid resins

Example 1 Polyvinyl Ester Solid Resin 1 (PVE 1): 691.97 g vinyl acetate, 9.29 g acetaldehyde and 0.197 g t-butyl peroxy-2-ethylhexanoate (TBPEH) were placed in a 3 l laboratory reactor. While stirring, it was heated to reflux (= start of the reaction). It was polymerized under reflux for 4 h. Then the solvent and unreacted monomer were removed by distillation, first under normal pressure then in vacuo. Analyzes: Viscosity: 5.91 mPas (Höppler viscosity: determined according to DIN 53015 in a 10% strength solution in ethyl acetate at 20 ^° C.); Mw = 92,592 g / mol; Mn = 35 056 g / mol (Mw and Mn determined (by SEC "Size Exclusion Chromatography") using a polystyrene standard in THF at 60 ⁰ C); polydispersity = 2.64, glass transition temperature Tg = 42.0 C ⁰ ,

Example 2: Polyvinyl Ester Solid Resin 2 (PVE 2): In a 3 liter laboratory reactor, 136.43 g of ethanol; 7.18 g of hydroxyethyl acrylate; 72.53 g isopropenyl acetate; 610.355 g of vinyl acetate and 2.87 g of tert-butyl per-2-ethylhexanoate (TBPEH). While stirring, it was heated to reflux (= start of reaction). At the beginning of the reaction, a dosage of 28.72 g of hydroxyethyl acrylate was added. The monomer was metered at a uniform rate and extended over a period of 4 h. After the end of the monomer metering, the mixture was stirred under reflux for a further 2 hours. Subsequently, the solvent and unreacted monomer was removed by distillation, first under normal pressure then in vacuo. Analyzes: Viscosity: 4.6 mPas (Höppler viscosity: determined according to DIN 53015 in a 10% strength solution in ethyl acetate at 20 ^° C.); Mw = 77.769 g / mol; Mn = 25 243 g / mol (Mw and Mn determined (by SEC "Size Exclusion Chromatography") using a polystyrene standard in THF at 60 ⁰ C); polydispersity = 3.1; glass transition temperature Tg = 40.6 C ⁰ ,

Example 3 Polyvinyl Ester Solid Resin 3 (PVE 3):

In a 3 liter laboratory reactor, 138.43 g of ethanol; 7.29 g of hydroxyethyl acrylate; 692.13 g of vinyl acetate and 2.91 g of tert-butyl per-2-ethylhexanoate (TBPEH) submitted. While stirring, it was heated to reflux (= start of reaction). At the beginning of the reaction, a dosage of 29.14 g of hydroxyethyl acrylate was added. The monomer metering was carried out at a uniform metering rate and extended over a period of 4 hours. After the end of the monomer metering, the mixture was stirred under reflux for a further 2 hours. Subsequently, the solvent and unreacted monomer was removed by distillation, first under normal pressure then in vacuo. Analyzes: Viscosity: 5.3 mPas (Höppler viscosity: determined according to DIN 53015 in a 10% strength solution in ethyl acetate at 20 ° C.); Mw = 89,090 g / mol; Mn = 22,089 g / mol (Mw and Mn determined (by SEC "Size Exclusion Chromatography") using a polystyrene standard in THF at 60 ⁰ C); polydispersity = 4.0; glass transition temperature Tg = 39.0 C ⁰ ,

Example 4 Polyvinyl Ester Resin 4 (PVEs 4):

In a 3 liter laboratory reactor, 154.186 g of ethanol; 7.00 g

Hydroxyethyl acrylate; 560.68 g of vinyl acetate and 1.40 g of tert-butyl per-2-ethylhexanoate (TBPEH) submitted. While stirring, it was heated to reflux (= start of reaction). At the beginning of the reaction, a dosage of 133.16 g of hydroxyethyl acrylate was added. The monomer was metered at a uniform rate and extended over a period of 4 h. After the end of the monomer metering, the mixture was stirred under reflux for a further 2 hours. Subsequently, the solvent and unreacted monomer is removed by distillation, first under atmospheric pressure then in vacuo. Analyzes: Viscosity: = 4.2 mPas (Höppler viscosity: determined according to DIN 53015 in a 10% strength solution in ethyl acetate at 20 ^° C.); Mw = 94,743 g / mol; Mn = 35,529 g / mol (Mw and Mn determined (by SEC "Size Exclusion Chromatography") using a polystyrene standard in THF at 60 ⁰ C); poly dispersity = 2.7; glass transition temperature Tg = 36.9 ° C ,

Production of the varnishes

Varnish 1 (Fl):

15 parts by weight of the solid polyvinyl ester resin from Example 1 and 7.14 parts by weight of ester-soluble nitrocellulose NC E24 (65%) from Synthesia were added in a mixture of 38.9 parts by weight of anhydrous ethanol and 38.9 parts by weight of ethyl acetate with stirring Normal conditions according to DIN50014 solved.

Varnish 2 (F2): 15 parts by weight of the polyvinyl ester solid resin from Example 2 and 7.14 parts by weight of ester-soluble nitrocellulose NC E24 (65%) from Synthesia were dissolved in a mixture of 38.9 parts by weight of anhydrous ethanol and 38.9 parts by weight of E Ethyl acetate dissolved under stirring at normal conditions according to DIN50014.

Varnish 3 (F3):

15 parts by weight of the solid polyvinyl ester resin from Example 3 and 7.14 parts by weight of ester-soluble nitrocellulose NC E24 (65%) from Synthesia were stirred in a mixture of 38.9 parts by weight of anhydrous ethanol and 38.9 parts by weight of ethyl acetate with stirring under normal conditions DIN50014 solved

Varnish 4 (F4):

15 parts by weight of the solid polyvinyl ester resin from Example 4 and 7.14 parts by weight of ester-soluble nitrocellulose NC E24 (65%) from Synthesia were mixed in a mixture of 38.9 g of anhydrous ethanol and 38.9 parts by weight of ethyl acetate are dissolved with stirring under normal conditions according to DIN50014.

Varnish 5: (VF5):

35. 97 parts by weight of the polyurethane resin Versamid PUR 1020 (42% FG), Cognis and 7.74 parts by weight of ester-soluble nit- rocellulose NC E24 (65%) from. Synthesia were in a mixture of 20.07 parts by weight of 2-propanol and 18.44 parts by weight of n-propyl acetate are dissolved with stirring under normal conditions according to DIN50014.

Production of printing inks

Printing ink 1 (DF 1):

9 parts by weight of the pigment Irgalith Blue GLO Fa. Ciba SC were in 41 parts by weight of varnish 1 for 60 minutes under normal conditions according to DIN50014 in Disperser Fa. Lau using glass beads as regrind (diameter: 2mm, in the volume ratio 1: 1 ) dispersed.

Printing ink 2 (DF 2):

9 parts by weight of the pigment Irgalith Blue GLO from Ciba SC were added in 41 parts by weight of varnish 2 for 60 minutes

Normal conditions according to DIN50014 in the disperser of Fa. Lau using glass beads as regrind (diameter: 2 mm, in a volume ratio 1: 1) dispersed.

Printing ink 3 (DF 3):

9 parts by weight of the pigment Irgalith Blue GLO Fa. Ciba SC were in 41 parts by weight of the varnish 3 for 60 minutes under normal conditions according to DIN50014 in the disperser from Fa. Lau using glass beads as regrind (diameter: 2mm, in the volume ratio 1 : 1) dispersed. Printing ink 4 (DF 4):

9 parts by weight of the pigment Irgalith Blue GLO Fa. Ciba SC were in 41 parts by weight of the varnish 4 for 60 minutes under normal conditions according to DIN50014 in the disperser from Fa. Lau using glass beads as regrind (diameter: 2mm, in the volume ratio 1: 1 ) dispersed.

Comparative printing ink 1 (VDF 1)

18.33 parts by weight of the pigment Irgalith Blue GLO Fa. Ciba SC were in 82.22 parts by weight of the varnish 5 for 60 minutes under normal conditions according to DIN50014 in the disperser of Fa.

Lau using glass beads as regrind (diameter:

2mm, in the volume ratio 1: 1) dispersed.

Subsequently, 21.00 parts by weight of a mixture of 10.5 parts by weight of 2-propanol and 10.5 parts by weight of n-

Propyl acetate added and mixed well.

Comparative printing ink 2 (VDF 2)

18.33 parts by weight of the pigment Irgalith Blue GLO Fa. Ciba SC were in 82.22 parts by weight of the varnish 5 for 60 minutes under normal conditions according to DIN50014 in the disperser of Fa.

Lau using glass beads as regrind (diameter:

2mm, in the volume ratio 1: 1) dispersed.

Subsequently, 21.00 parts by weight of a mixture of 9.0 parts by weight of 2-propanol, 9.0 parts by weight of n-propyl acetate and 3.0 parts by weight of Vertec IAlO (adhesion promoter) of the Fa.

Johnson Matthey added and mixed well.

Printing ink 5 (DF 5): 9 parts by weight of the pigment Irgalith Rubin 4BGL from Ciba SC were used in 41 parts by weight of the varnish 2 for 60 minutes under normal conditions according to DIN50014 in the disperser from Lau using glass beads as ground material (diameter: 2 mm). in the volume ratio 1: 1) dispersed.

Ink 6 (DF 6):

9 parts by weight of the pigment Irgalith Rubin 4BGL from Ciba

SC were added in 41 parts by weight of the varnish 3 for 60 minutes Normal conditions according to DIN50014 in the disperser of Fa. Lau using glass beads as regrind (diameter: 2 mm, in a volume ratio 1: 1) dispersed.

Production of the printed polymer substrates

In each case, one of the printing inks DF1 to DF6 or VDF1 or VDF2 was knife-coated by Erichsen in the form of a bubble-free film and has a wet film thickness of 24 μm

OPP film (oriented polypropylene) or a PET film (polyethylene terephthalate) applied, then dried for 20 seconds with hot air (about 50 ⁰ C) and finally stored for 16 hours under normal conditions according to DIN50014. The resulting printed polymer substrates were further processed into printed polymer composites.

Production of printed polymer composites

On a PE film (polyethylene) or an OPP film (oriented polypropylene), the adhesive Liofol UK 3640 and the hardener UK 6800 Fa. Henkel were applied with a squeegee in the form of a bubble-free film and a wet film thickness of 12 microns wet and 30 seconds under normal conditions

DIN50014, resulting in a film coated with adhesive.

The respective printed polymer substrate (printed OPP film or printed PET film) was produced as described above and laid with the non-printed side on a flat and clean surface.

The respective adhesive-coated film was placed with its adhesive-coated side on the printed side of the printed polymer substrate and rolled over with a roll without additional pressure. The composite thus obtained was then cured for 24 hours under normal conditions according to DIN50014. Subsequently, from the printed polymer composite with 5 punched test pieces with a width of 15 mm and a length of 50-100 mm.

The printed polymer composites thus produced are listed in Tabel ^¬ le second

Application technical tests

Gloss, transparency, colorimetry: The results of the performance testing of the ink to Dfl DF6 or VDFl and VDF2 grew ^¬ results in Table 1 below. The measurements were measured with the Spectro-guide sphere gloss spectrometer (Byk Gardner, color system: CIELab, gloss measurement angle: 60 °). The gloss given in Table 1 is dimensionless

Code and was determined photometrically from the ratio of the overall teaching ended reflected portion of the diffusely reflected portion of a light incident on the respective ink ^¬ light beam determined (determined by Din67530). The transparency of the respective printing ink was determined according to DIN 55988 ("Determination of the transparency number (glaze) of pigmented and unpigmented systems; colorimetric methods") The dimensionless coordinates L *, a *, b * given in Table 1 correspond to the standard coordinates of the CIELAB. Color space (DIN 7174).

Table 1:

Aus Tabelle 1 geht hervor, dass der Glanz der erfindungsgemä^¬ ßen Druckfarben (DFl bis DF4) gegenüber herkömmlichen Druckfarben (VDFl und VDF2) enthaltend jeweils dasselbe Pigment hö^¬ her ist. Mit den erfindungsgemäßen Polyvinylacetat-Festharzen enthaltend Hydroxy-funktionelle Acrylsäureester-Einheiten (DF3 bis DF4) sind im Vergleich zu Festharzen von Polyvinylacetat- Homopolymerisaten (DFl) Druckfarben mit höherer Transparenz zugänglich.

From Table 1 it appears that the gloss of the invention ^shown SEN printing inks in each case the same pigment HOE (DFL to DF4) compared with conventional printing inks (VDFl and VDF2) containing ^¬ forth. With the polyvinyl acetate solid resins according to the invention containing hydroxy-functional acrylic acid ester units (DF3 to DF4) printing inks having higher transparency are obtainable in comparison with solid resins of polyvinyl acetate homopolymers (DF1).

Measurement of the bond strength of the printed polymer composites

To determine the bond strength of the printed polymer composites, the peel resistance for the respective test specimen was determined in accordance with DIN 53357. The measurement of the peeling resistance, at ^¬ given in N / 15mm was measured with a tensile tester (Zwick Universalzugprüfmaschine) at a peel angle of 180 ° and a speed of 100 mm / min carried out. The results listed in Table 2 are averages of 5 measurements per printed polymer composite.

Table 2:

The comparative printing ink 1 (VDF1) contained PUR with Versamid

1020 a commercially available polyurethane resin as a polymeric binder, which according to the manufacturer's instructions for the Use in printing inks and is well tolerated with cellulose nitrate. However, the adhesive strengths of the imprints of VDF1 on the various polymer substrates were far lower than in the case of the use of printing inks according to the invention (Table 2, VDF1, DF1 to DF6).

The reference ink VDF2 additionally contained the titanate-based adhesion promoter Vertec IA10. Although the adhesive strengths of imprints on polymer substrates were higher when using the printing ink VDF2 compared to the corresponding use of the reference printing ink VDF1, they generally remained far behind the imprints obtainable according to the invention. This is all the more remarkable, as were used in the procedure according to the invention printing inks without adhesion promoter.

The results summarized in Table 2 thus illustrate the increase in adhesive strengths associated with the use of printing inks according to the invention (printing inks DF1 to DF6). The increase in adhesive strengths is evident when printing the critical polymer substrates PE and PET (Table 2, DF1 to DF6, VDF1 and VDF2), regardless of the pigment used (Table 2, DF1 to DF4 or DF5 to DF6).

Printing inks based on cellulose nitrate as the sole binder give, after application to polymer substrates, brittle imprints which flake off polymer substrates even under low mechanical stress, as is known, for example, from DE-A 3525925. On the other hand, the printed polymer substrates or printed polymer composites obtained with the printing inks DF1 to DF6 according to the invention were flexible and not brittle, so that the prints did not peel off on mechanical loading of the substrates printed according to the invention, although the printing inks DF1 to DF6 contained no plasticizers or adhesion promoters.

Claims

Claims: 1. The use of printing inks for printing on polymer substrates, wherein the inks contain one or more cellulose derivatives, one or more colorants, organic Lösemit ^¬ tel and optionally other additives, characterized in that additionally one or more polyvinyl ester solid resins based on a ) one or more vinyl esters, if appropriate b) one or more hydrophilic monomers and optionally c) one or more hydrophobic monomers, wherein the data in% by weight relate to the total weight of the polyvinyl ester solid resin. 2. Use of printing inks according to claim 1, characterized in that as vinyl ester a) one or more vinyl esters of unbranched or branched carboxylic acids having 2 to 15 carbon atoms are used. 3. Use of printing inks according to claim 1 or 2, characterized in that as hydrophilic monomers b) one or more monomers are used selected from the group consisting of hydroxy- or amino-functional methacrylic acid esters and acrylic esters of alcohols having 1 to 15 C Atoms, ethylenically unsaturated mono- and dicarboxylic acids or their anhydrides, ethylenically unsaturated carboxylic acid amides and Cabonsäurenitrile, monoesters of fumaric acid and maleic acid and ethylenically unsaturated sulfonic acids. 4. Use of printing inks according to claim 1 to 3, characterized in that are used as cellulose derivatives cellulose esters, such as cellulose nitrate, cellulose propionate, cellulose acetobutyrate (CAB), or cellulose ethers, such as methylcellulose, ethylcellulose or hydroxypropylmethylcellulose (HPMC). 5. Use of printing inks according to claim 1 to 4, characterized in that are used as colorants pigments, dyes or mixtures of pigments and dyes. 6. Use of printing inks according to claim 1 to 5, characterized in that are used as polymer substrates polyalkylenes, polyamides, polyesters or polyvinyl halides, which are optionally metallized. 7. Polyvinyl acetate solid resins obtainable by free-radically initiated polymerization of vinyl acetate, one or more hydroxy-functional methacrylic acid esters or acrylic acid esters of alcohols having 1 to 15 carbon atoms and optionally one or more further monomers, characterized in that α) 90 to 99.9 wt .-% vinyl acetate and ß) 0.1 to 10 wt .-% of one or more hydroxy-functional methacrylic acid esters or acrylic acid esters of alcohols having 1 to 15 carbon atoms are copolymerized, wherein the information in wt. Add% to 100% by weight each. 8. A process for preparing the solid polyvinyl acetate resins by free-radically initiated polymerization of vinyl acetate, one or more hydroxy-functional methacrylic acid esters or acrylic acid esters of alcohols having 1 to 15 carbon atoms and optionally one or more other monomers, characterized in that α) 90 bis 99.9 wt .-% of vinyl acetate and ß) 0.1 to 10 wt .-% of one or more hydroxy-functional methacrylic acid esters or acrylic acid esters of alcohols having 1 to 15 carbon atoms are copolymerized, wherein the data in wt. Add% to each 100 wt .-%. 9. Printed polymer substrates obtainable by applying one or more printing inks to polymer substrates and then drying. 10. Printed polymer substrates according to claim 9, characterized in that one or more printing inks are applied to the polymer substrates by film printing or gravure printing processes. 11. Printed polymer composites, characterized in that one or more further polymer substrates are applied to a printed polymer substrate.