WO2002062577A1

WO2002062577A1 - Transparent, antimicrobial, biaxially orientated, partially crystallised film made from crystallisedthermoplastic

Info

Publication number: WO2002062577A1
Application number: PCT/EP2002/000853
Authority: WO
Inventors: Ursula Murschall; Ulrich Kern; Klaus Oberländer; Harald Hessberger
Original assignee: Mitsubishi Polyester Film Gmbh
Priority date: 2001-02-05
Filing date: 2002-01-28
Publication date: 2002-08-15

Abstract

The invention relates to a single or multi-layered, transparent, biaxially orientated and thermofixed, partially crystallised film made from crystallised thermoplastic which is the main component thereof. Said thermoplastic comprises an antimicrobial active part of 2.4.4'-trichloro-2'-hydroxy-diphenyl ether (triclosan) and is optionally provided with at least one additional function. The additional function is for example, that the film is stabilised against UV radiation, is flame retarding, is coated on either one side or both sides, can be sealed and/or is corona-treated or inflammable. The film is generally produced by extrusion or coextrusion, the triclosan and the compounds provided for the additional functions being added in the form of a pre-dried or pre-crystallised master batch. The inventive film is suitable for use in the medical field, internally or externally, in addition to packaging and sanitation.

Description

Transparent, antimicrobial, biaxially oriented, partially crystalline film made of a crystallizable thermoplastic

The invention relates to a high-gloss, single- or multilayer, transparent, biaxially oriented and heat-set, partially crystalline film which contains at least one crystallizable thermoplastic as the main component. It also relates to a method for producing these films and their use.

Films of the type mentioned, in particular films based on polyethylene terephthalate, are known and have been described in large numbers. They are not protected against the growth of mold or other microorganisms.

Functionalized polyester films without antimicrobial finish are also known and are described in numerous variants. For example, the multilayer, biaxially oriented and heat-set polyester film according to GB-A 1 465973 comprises a layer of transparent polyethylene terephthalate (PET) and a layer of likewise transparent copolyester. A rough structure can be impressed on the surface of the copolyester layer with the aid of rollers, so that the film can be written on.

EP-A 035835 describes a biaxially stretched and heat-set, multilayer polyester film which comprises a layer made of a highly crystalline polyester and, in connection therewith, a sealable layer made of an essentially amorphous, linear polyester. The latter layer contains finely divided particles, the mean diameter of the particles being greater than the layer thickness. These particles form surface protrusions that prevent unwanted blocking and sticking to rollers or guides. This makes it easier to wind up and process the film. The choice of particles with a larger diameter than the sealing layer and the concentrations given in the examples worsens the sealing behavior of the film. The seal seam strength of the sealed film at 140 ° C. is in a range from 63 to 120 N / m (0.97 N / 15 mm to 1.8 N / 15 mm film width).

EP-A 432 886 describes a coextruded film with a polyester base layer, a cover layer made of a sealable polyester and a polyacrylate coating on the back. The sealable top layer can consist of a copolyester with units of isophthalic acid and terephthalic acid. The film on the back has improved processing properties. The seal seam strength is measured at 140 ° C. A seal seam strength of 761.5 N / m (11.4 N / 15 mm) is specified for an 11 μm thick sealing layer. A disadvantage of the rear acrylic coating is that this side no longer seals against the sealable top layer. The film can therefore only be used to a very limited extent.

A coextruded, multilayer, sealable polyester film is also in the

EP-A 515 096. The base layer of the film can contain pigment particles, in particular those made of aluminum oxide, titanium dioxide, alkali metal carbonate, calcium sulfate or barium sulfate. This leads to a white film. The sealable layer additionally contains pigmentation particles, preferably silica gel particles. The particles can also be applied to the already extruded film, for example by coating with an aqueous silica gel dispersion. As a result, the film should maintain the good sealing properties and be easy to process. The back contains very few particles that get into this layer mainly through the regranulate. The seal seam strength is measured at 140 ° C and is more than 200 N / m (3 N / 15 mm). For a 3 μm thick

The sealing layer is given a sealing seam strength of 275 N / m (4.125 N / 15 mm).

The coextruded, multilayer polyester film known from WO 98/06575 comprises a sealable cover layer and a non-sealable base layer. The

The base layer can be constructed from one or more layers, wherein the inner layer is in contact with the sealable layer. The other (outer) layer then forms the second, non-sealable cover layer. ^' The sealable top layer can also consist of copolyesters with units of isophthalic acid and terephthalic acid. However, the top layer contains no antiblock particles. The film also contains at least one UV absorber in the

Base layer is contained in a proportion of 0.1 to 10.0 wt .-%. Zinc oxide or titanium dioxide particles with an average diameter of less than 200 nm, but preferably triazines (for example ^® Tinuvin 1577 from Ciba) are used as UV absorbers. The base layer is equipped with common antiblocking agents. The film is characterized by a good sealability, but does not have the desired processing behavior and also has deficits in the optical properties.

Layers of copolyester can also be produced by applying an appropriate aqueous dispersion. For example, EP-A 144 978 describes a polyester film which has a continuous coating made of the copolyester on at least one side. The dispersion is applied to the film before stretching or before the last stretching step. The polyester coating consists of a condensation product of various monomers that are capable of forming polyesters, such as isophthalic acid, aliphatic dicarboxylic acids,

Sulfomonomers and aliphatic or cycloaliphatic glycols.

DE-A 23 46 787 discloses, inter alia, flame-retardant films made from linear polyesters modified with carboxyphosphinic acids. However, there are a number of problems associated with making these films. The raw material is very sensitive to hydrolysis and must be pre-dried very well. When drying the raw material with dryers that correspond to the prior art, it sticks together, so that a film can only be produced under the most difficult conditions. The films produced under extreme, uneconomical conditions also become brittle when exposed to temperature. The mechanical properties create decrease so much that the film becomes unusable. This embrittlement occurs after 48 hours of thermal stress.

The object was therefore to provide a transparent, biaxially oriented, partially crystalline film which has good mechanical and optical properties and is antimicrobially treated. The film should also be high-gloss.

The object is achieved with a foil on the basis of crystallizable thermoplastics, the 2,4,4 ^{^{'-trichloro-2'}} -hydroxy-diphenyl ether (Triclosan) as an anti-microbially effective means. This solution is surprising insofar as numerous of the antimicrobial active substances customary hitherto have had a negative effect on the production process and / or on the optical properties of the product.

The subject of the present application is accordingly a single-layer or multilayer, transparent, biaxially oriented and heat-set, partially crystalline film with a crystallizable thermoplastic as the main component, which is characterized in that the film or at least one layer therein contains an antimicrobial component of 2,4 , 4 ^' -Trichlor-2 ^' -hydroxy-diphenyl ether (triclosan).

Antimicrobial means that the growth of gram-positive and gram-negative bacteria as well as mold and yeast is greatly reduced, i.e. that the antimicrobial film is at least not overgrown by the test culture and that the growth around the film is inhibited (Hemmhof).

Gram-negative bacteria are, for example, escherichia coli, klebsiella pneumoniae, proteus vulgaris or salmonella. Gram-positive bacteria are, for example, staphylococcus aureus, streptococcus faecalis, micrococcus luteus or corynebacterium minutissimum. Pure, defined microorganisms such as pseudomonas aeruginosa, staphylococcus aureus and escherichia are used as test organisms coli, aspergillus niger, penicillium funicolosum, chaetomium globosum, trichoderme viride or candida albicans are used. If there is no active substance against the organism, the test organism will overgrow the film sample and thus the entire surface of the petri dish.

In order to achieve a sufficient antimicrobial effect, the proportion of triclosan is generally between 0.01 and 10% by weight, preferably between 0.1 and 5% by weight, in each case based on the total weight of the single-layer film or the relevant layer the multilayer film.

Despite the antimicrobial finish, the film according to the invention has good optical properties, in particular a high surface gloss of more than 100, preferably more than 110, a light transmission of more than 64%, preferably more than 66% and a haze of less than 30%, preferably less than 25%.

The good mechanical properties include a high modulus of elasticity (in the longitudinal direction = machine direction (MD) greater than 3,500 N / mm ² , preferably greater than 3,800 N / mm ² ; in the transverse direction (TD) greater than 4,200 N / mm ² , preferably greater than 4,500 N / mm ² ; each determined according to ISO 527-1-2) as well as good tensile strength values (in MD more than 100 N / mm ² ; in TD more than 180 N / mm ² ) and good elongation at break values (in MD more than 90%; in TD more than 70%).

The film can be easily and longitudinally oriented in its manufacture both in the longitudinal and in the transverse direction. The oriented (= stretched) film generally has a thickness of 1 to 500 μm.

The main component of the film is a crystallizable thermoplastic.

Suitable crystallizable or partially crystalline thermoplastics are, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), bibenzolmodisiert.es polyethylene terephthalate (PETBB), bibenzol- modified polybutylene terephthalate (PBTBB) and bibenzene-modified polyethylene naphthalate (PENBB), with polyethylene terephthalate (PET) and bibenzene-modified polyethylene terephthalate (PETBB) being preferred.

In the context of the present invention, “crystallizable thermoplastics” should be understood to mean crystallizable homopolymers, crystallizable copolymers, crystallizable compounds, crystallizable recyclate or other variations of crystallizable thermoplastics.

In addition to the main monomers such as dimethyl terephthalate (DMT), ethylene glycol (EG), propylene glycol (PG), butane-1, 4-diol, terephthalic acid (TA), benzenedicarboxylic acid and / or naphthalene-2,6 -dicarboxylic acid (NDA), also isophthalic acid (IPA) and / or eis and / or tet7s-1, 4-cyclohexane-dimethanol (c-CHDM, £ -CHDM or c / tC DM) can be used. The standard viscosity SV (DCE) of the polyethylene terephthalate is generally between 600 and 1,000, preferably between 700 and 900.

Preferred starting materials for the production of the film according to the invention are crystallizable thermoplastics with a crystallite melting temperature Tm of 180 to

365 ° C and more, preferably from 180 to 310 ° C, with a crystallization temperature range Tc between 75 ° C and 280 ° C, a glass transition temperature Tg from 65 to 130 ° C (determined by differential scanning calorimetry (DSC) at a heating rate of 20 ° C / min), with a density of 1, 10 to 1, 45 (determined according to DIN 53479) and a crystallinity between 5 and 65%, preferably 20% and 65%.

The bulk density (measured according to DIN 53466) is between 0.75 kg / dm ³ and 1.0 kg / dm ³ , preferably between 0.80 kg / dm ³ and 0.90 kg / dm ³ . The polydispersity (= ratio of Mw to Mn) of the thermoplastic, measured by gel permeation chromatography (GPC), is preferably between 1.5 and 4.0, particularly preferably between 2.0 and 3.5.

"Main component" means that the proportion of at least one partially crystalline

Thermoplastics is preferably between 50 and 99% by weight, particularly preferably between 75 and 95% by weight, in each case based on the total weight of the film or the total weight of the layer in the film. In addition to triclosan, the remaining fractions can make up other antimicrobial compounds and other additives which are customary for biaxially oriented, transparent films.

In addition to triclosan, the film according to the invention can contain other antimicrobial compounds. These are, for example, 10,10 ^{'-oxy-bisphenoxarsine,} N- trihalogenomethylthio phthalimide, Diphenylantimon-2-ethylhexanoate, copper-8-hydroxy-quinoline, tributyltin oxide and its derivatives and halogenated derivatives

Diphenyl ether compounds as described in WO 99/31036. Derivatives of 2,4,4 ^{'trichloro-2-hydroxy-diphenyl} ether (Triclosan) are particularly preferred because they have an improved migration behavior, thermally stable and are little volatile.

The film according to the invention can also be multi-layered. It then comprises a core layer and at least one cover layer. Three-layer films with an A-B-A or A-B-C structure are particularly preferred (B = core or base layer, A and C = outer layers).

For this embodiment it is essential that the crystallizable thermoplastic of the core layer has a standard viscosity similar to that in the adjacent cover layer (s). In a particular embodiment, the cover layers consist of a polyethylene naphthalate or a polyethylene terephthalate / polyethylene naphthalate or a compound. In the multi-layer embodiment, the triclosan is preferably contained in the core layer. Instead of, or in addition to, the core layer, the cover layers and / or any intermediate layers which may be present can also be equipped with it. In contrast to the single-layer embodiment, the proportions of the additives here relate to the weight of the thermoplastics in the layer in question.

Depending on the intended use, the film can also be functionalized. The additional functionality is preferably that the film is UV stabilized, flame retardant, sealable, coated on one or both sides, corona and / or flame treated. This makes the film sealable, printable, writable, antistatic, metallizable or sterilizable, for example.

A preferred embodiment is that the transparent film according to the invention is UV-stable. Light, especially the ultraviolet portion of solar radiation, i.e. H. the wavelength range from 280 to 400 nm induces degradation processes in thermoplastics. The result of this is that not only does the visual appearance change as a result of color change or yellowing, but also the mechanical-physical properties of the films made of the thermoplastics are extremely negatively influenced. The prevention of these photooxidative degradation processes is of considerable technical and economic importance, since otherwise the application possibilities of numerous thermoplastics are drastically restricted. Polyethylene terephthalates, for example, begin to absorb UV light below 360 nm; your

Absorption increases considerably below 320 nm and is very pronounced below 300 nm. The maximum absorption is in the range between 280 and 300 nm. In the presence of oxygen, mainly chain cleavages are observed, but no cross-links. Carbon monoxide, carbon dioxide and carboxylic acids are the predominant quantities of photo-oxidation products. In addition to the direct photolysis of the ester groups, oxidation reactions are considered, which also result in the formation of carbon dioxide via peroxide radicals. The photooxidation of polyethylene terephthalates can also lead to hydroperoxides and their decomposition products and the associated chain cleavages via elimination of hydrogen in the α-position of the ester groups (H. Day, DM Wiles, J. Appl. Polym. Sei. 16 [1972] S.

203).

UV stabilizers, i.e. UV absorbers as light stabilizers are chemical compounds that intervene in the physical and chemical processes of light-induced degradation. Soot and other pigments can partially protect against light. However, these substances are unsuitable for transparent films because they lead to discoloration or color change. Suitable UV stabilizers as light stabilizers are UV stabilizers which absorb at least 70%, preferably at least 80%, particularly preferably at least 90%, of the UV light in the wavelength range from 180 to 380 nm, preferably 280 to 350 nm.

Particularly suitable UV stabilizers are also thermally stable in the temperature range from 260 to 300 ° C, i.e. they do not decompose into fission products and do not outgas. Suitable UV stabilizers as light stabilizers are, for example, 2-hydroxy-benzophenones, 2-hydroxy-benzotriazoles, organo-nickel compounds, salicylic acid esters, cinnamic acid ester derivatives, resorcinol monobenzoates, oxalic acid anilides, hydroxybenzoic acid esters, benzoxazinones, sterically hindered amines and triazines, the 2 -Hydroxy-benzotriazoles, the benzoxazinones and the triazines are preferred. It was completely surprising for the experts that the use of UV stabilizers in combination with an antimicrobial finish leads to useful films with excellent properties. The person skilled in the art would probably have first tried to achieve a certain UV stability via an oxidation stabilizer, but would have found after weathering that the film quickly turns yellow.

UV stabilizers are known from the literature which absorb UV radiation and thus offer protection. The specialist would then have one of these known and commercial UV stabilizers used, but found that the UV stabilizer has a poor thermal stability and decomposes or outgasses at temperatures between 200 and 240 ° C. In order not to damage the film, he would have had to incorporate large amounts (approx. 10 to 15% by weight) of UV stabilizer so that it really absorbs the UV light effectively. At these high concentrations, however, the film yellows shortly after production. The mechanical properties are also adversely affected. Unusual problems arise during stretching, such as tears due to insufficient strength, ie modulus of elasticity, nozzle deposits, which leads to profile fluctuations, deposition of UV stabilizer on the rollers, which adversely affects the optical properties (severe clouding, adhesive defect, inhomogeneous surface) leads, and deposits in the stretching and fixing frame that drip onto the film.

It was therefore surprising that even with low concentrations of UV

Stabilizer an excellent UV protection is achieved. It was particularly surprising that the yellowness index of the film does not change compared to a non-stabilized film within the scope of the measurement accuracy. There are also no outgassing, nozzle deposits or frame evaporation, which gives the film an excellent appearance, an excellent profile and an excellent

Flatness. The UV-stabilized film can be stretched excellently, so that it can be produced reliably and reliably on so-called "high speed film lines" up to speeds of 420 m / min. This means that the film can also be produced economically. Furthermore, it is very surprising that the regenerate can also be used again without adversely affecting the yellowness index of the film.

In a very particularly preferred embodiment, the film according to the invention contains 0.1 to 5.0% by weight of 2- (4,6-diphenyl- [1,3,5] triazin-2-yl) -5- as UV stabilizer. hexyloxy-phenol of the formula

or 0.1 to 5.0% by weight of 2,2 ^, -methylene-bis- [6-benzotriazol-2-yl-4- (1, 1, 2,2-tetra-methyl-propyl) phenol] of the formula

or 0.1 to 5.0% by weight of 2,2 '- (1,4-phenylene) -bis - ([3.1] benzoxazin-4-one) of the formula

In a further embodiment, mixtures of these UV stabilizers or mixtures of at least one of these UV stabilizers with other UV stabilizers can be used, the total concentration of light stabilizers preferably being between 0.1 and 5.0% by weight, particularly preferably in the range from 0.5 to 3.0% by weight, based on the weight of the finished layer. In a further embodiment, the film according to the invention is flame-retardant. Flame retardant means that the film meets the conditions according to DIN 4102 part 2 and especially the conditions according to DIN 4102 part 1 in a so-called fire protection test and can be classified in building material class B 2 and especially B1 of the flame retardant materials. Furthermore, the optionally flame-retardant film should pass the UL test 94 "Horizontal Burning Test for Flammability of Plastic Material" so that it can be classified in class 94 VTM-0. The film accordingly contains a flame retardant which is metered in directly during film production using the so-called masterbatch technology, the proportion of the flame retardant being in the range from 0.5 to 30.0% by weight, preferably from 1.0 to 20.0 % By weight, based on the weight of the layer of the crystallizable thermoplastic, is. The proportion of the flame retardant in the masterbatch is generally 5.0 to 60.0% by weight, preferably 10.0 to 50.0% by weight, in each case based on the total weight of the masterbatch. Suitable flame retardants are, for example

Bromine compounds, chlorinated paraffins and other chlorine compounds, antimony trioxide and aluminum trihydrates. However, the halogen compounds have the disadvantage that halogen-containing by-products can arise. In the event of fire, hydrogen halides in particular arise. Another disadvantage is the low lightfastness of a film equipped with it. Other suitable flame retardants are, for example, organic phosphorus compounds such as carboxyphosphinic acids, their anhydrides and alkanephosphonic diesters, preferably methanephosphonic diesters, especially methanephosphonic acid bis- (5-ethyl-2-methyl-2-oxo-2λ ⁵ - [1, 3.2] dioxaphosphinane 5-ylmethyl ester), available under the designation ^® Amgard P1045 from Albright & Wilson, USA. It is essential that the organic phosphorus compound is soluble in the thermoplastic, since otherwise the required optical properties will not be met.

Since the flame retardants generally have a certain sensitivity to hydrolysis, the additional use of a hydrolysis stabilizer can be useful.

As a hydrolysis stabilizer, phenolic stabilizers, alkali or alkaline earth stearates and / or alkali or alkaline earth carbonates in amounts of 0.01 to 1.0% by weight. Phenolic stabilizers are preferred in an amount of 0.05 to 0.6% by weight, in particular 0.15 to 0.3% by weight and with a molar mass of more than 500 g / mol. Pentaerythritol tetrakis [3- (3,5-di-fe / t-butyl-4-hydroxyphenyl) propionate] or 1,3,5-trimethyl-2,4,6-tris are particularly advantageous

(3,5-di-te / t-butyl-4-hydroxy-benzyl) -benzene.

In this preferred embodiment, the flame-retardant film according to the invention contains, as the main constituent, a crystallizable PET, 1.0 to 20.0% by weight of an organic phosphorus compound which is soluble in the thermoplastic as a flame retardant and 0.1% by weight to 1.0% by weight. % of a hydrolysis stabilizer. Methanephosphonic acid bis- (5-ethyl-2-methyl-2-oxo-2λ ⁵ - [1, 3,2] dioxaphosphinan-5-ylmethyl ester) is preferred as the flame retardant. These proportions of flame retardant and hydrolysis stabilizer have also proven to be favorable when the main component of the film is not PET but a different thermoplastic.

Surprisingly, fire protection tests according to DIN 4102 and the UL test have shown that in the case of a three-layer film, it is quite sufficient to equip the 0.5 to 2 μm thick top layers with flame retardants in order to achieve improved flame retardancy. If required and with high fire protection requirements, the core layer can also be equipped with flame retardants. H. include so-called basic equipment.

In addition, measurements showed that the film according to the invention does not become brittle at a temperature load of 100 ° C. over a longer period of time. This result is attributed to the synergistic effect of suitable pre-crystallization, predrying, masterbatch technology and hydrolysis stabilizer. No embrittlement after thermal stress means that the film has no embrittlement and no disadvantageous mechanical properties after 100 hours of annealing at 100 ° C in a forced air oven.

The film according to the invention can be provided on one or both sides with a customary functional coating. The following can be used to produce the coating: acrylates according to WO 94/13476, ethyl vinyl alcohols, PVDC, water glass (Na ₂ Si0 ₄ ), hydrophilic polyesters such as PET / I PA polyesters containing 5-sodium sulfoisophthalic acid (EP-A 144 878 , US-A 4 252 885 or EP-A 296620), vinyl acetates (WO 94/13481), polyvinyl acetates, polyurethanes, alkali or

Alkaline earth metal salts of (C ₁₀ -C ₁₈ ) fatty acids, butadiene copolymers with acrylonitrile or methyl methacrylate, methacrylic acid, acrylic acid or their esters. In addition, the coating can contain conventional additives (for example antiblocking agents, pH stabilizers) in proportions of about 0.05 to 5.0% by weight, preferably 0.1 to 3.0% by weight, in each case based on the weight of the coating liquid , contain.

The substances or compositions mentioned are applied as a dilute - preferably aqueous - solution, emulsion or dispersion to one or both film surfaces. The solvent is then evaporated. The coating is preferably applied in-line, i.e. during the film production process, expediently before transverse stretching. Application by the "reverse gravure-roll coating" method, with which extremely homogeneous layer thicknesses are obtained, is particularly preferred. If the in-line coatings are applied after the longitudinal stretching, the temperature treatment before the transverse stretching is usually sufficient to volatilize the solvent and to dry the coating. The dried coatings then have layer thicknesses of 5 to 100 nm, preferably 20 to 70 nm, in particular 30 to 50 nm.

Wherever a very good sealability is required and where this property cannot be achieved via an in-line coating, this is the one according to the invention The film has at least three layers and then, in a particular embodiment, comprises the base layer B, a sealable cover layer A and an optionally sealable cover layer C. If the cover layer C is also sealable, then the two cover layers are preferably identical.

The sealable outer layer A applied to the base layer B by coextrusion is based on polyester copolymers and consists essentially of copolyesters which are composed predominantly of isophthalic acid, bibenzene carboxylic acid and terephthalic acid units and of ethylene glycol units. The remaining monomer units come from other aliphatic, cycloaliphatic or aromatic diols or dicarboxylic acids, as can also occur in the base layer. The preferred copolyesters which provide the desired sealing properties are those which are composed of ethylene terephthalate and ethylene isophthalate units and of ethylene glycol units. The proportion of ethylene terephthalate is 40 to 95 mol% and the corresponding proportion of ethylene isophthalate is 60 to 5 mol%. Preferred are copolyesters in which the proportion of ethylene terephthalate is 50 to 90 mol% and the corresponding proportion of ethylene isophthalate is 50 to 10 mol% and very preferred are copolyesters in which the proportion of ethylene terephthalate is 60 to 85 mol% and the corresponding The proportion of ethylene isophthalate is 40 to 15 mol%.

In principle, the same polymers that are also used in the base layer can be used for the optionally sealable cover layer C and for any intermediate layers.

The desired sealing and processing properties of the film according to the invention are obtained from the combination of the properties of the copolyester used for the sealable cover layer and the topographies of the sealable cover layer A and the optionally sealable cover layer C. The seal initiation temperature of 110 ° C. and the seal seam strength of at least 1.3 N / 15 mm is achieved if the copolymers described in more detail above are used for the sealable cover layer A. The best sealing properties of the film are obtained if no further additives, in particular no inorganic or organic fillers, are added to the copolymer. In this case, the lowest seal starting temperature and the highest seal seam strengths are obtained for a given copolyester. However, the handling of the film is poor in this case, since the surface of the sealable cover layer A tends to block. The film can hardly be wrapped and is not suitable for further processing on high-speed packaging machines. In order to improve the handling of the film and the processability, it is necessary to modify the sealable cover layer A. This is best done with the aid of suitable antiblocking agents of a selected size, which are added to the sealing layer in a specific concentration in such a way that, on the one hand, blocking is minimized and, on the other hand, the sealing properties are only insignificantly deteriorated.

In a further embodiment, the film is colored transparent. For this purpose, a dye that is soluble in the thermoplastic is generally used. The solubility of the dye is determined in accordance with DIN 55 949. Its proportion is expediently from 0.01 to 20.0% by weight, preferably 0.05 to 10.0% by weight, in each case based on the weight of the crystallizable thermoplastic. The transparent coloring of the film is due to a wavelength-dependent absorption of the light by the dye that is molecularly dissolved in the thermoplastic. Fat- or aromatic-soluble dyes, for example azo or

Anthraquinone. They are particularly suitable for coloring PET, because its high glass transition temperature Tg limits the migration of the dye (see J. Koerner, Soluble dyes in the plastics industry, in VDI-Gesellschaft Kunststofftechnik, coloring plastics, VDI-Verlag, Düsseldorf [1975]). Suitable soluble dyes are also C.I. Solvent Yellow 93 (a

Pyrazolone derivative), Cl solvent yellow 16 (a fat-soluble azo dye), fluorol green gold (a fluorescent polycyclic dye), Cl solvent red 1 (an azo dye), azo dyes such as Thermoplastrot BS, Sudan red BB, Cl solvent red 138 (an anthraquinone derivative), fluorescent benzopyran dyes such as fluorol red GK and fluorolange orange GK, Cl solvent blue 35 (an anthraquinone dye ), Cl solvent blue 15: 1 (a phthalocyanine dye) and mixtures thereof. The coloring with the soluble dyes is called transparent, translucent or translucent.

The soluble dye is preferably metered in using the masterbatch technology during film production, but can also be incorporated during the production of the raw material. The proportion of soluble dyes is generally 0.01 to 40.0% by weight, preferably 0.05 to 25.0% by weight, in each case based on the weight of the crystallizable thermoplastic.

To set further desired properties, the film can also be corona or flame treated. The treatment intensity is chosen so that the surface tension of the film is generally above 45 mN / m.

In addition to triclosan and the additives described so far, the base layer and / or top layer (s) can also contain other customary additives, such as stabilizers and

Antiblocking agents. They are expediently added to the polymer or the polymer mixture before the melting.

Mixtures of two or more different antiblocking agents or mixtures of antiblocking agents of the same composition but different particle size can also be selected as additives. The particles can be added to the individual layers in the usual concentrations, for example as a glycolic dispersion, during the polycondensation or via masterbatches during the extrusion. Pigment concentrations of 0.0001 to 10.0% by weight, based on the weight of the outer layers, have proven to be particularly suitable. The film is produced by processes known per se, for example by an extrusion process on an extrusion line. It has proven to be particularly advantageous to use the triclosan and also the other additives in the form of masterbatches. With a suitable predrying or pre-crystallization of the masterbatches, the film according to the invention can be used without

Make the glue in the dryer. Outgassing and deposits during the production process were not found. This is surprising in that the triclosan has a relatively low melting point.

An economical film production also includes that the used

Raw materials or raw material components can be dried with commercially available industrial dryers, such as vacuum, fluidized bed, fluidized bed or fixed bed dryers (shaft dryers). It is essential that the antimicrobial agents do not outgas or form wall coverings in the dryers, that the raw materials do not stick together and are not thermally broken down.

In a vacuum dryer, the raw material goes through a temperature range of approx. 30 to 130 ° C at a vacuum of 50 mbar. Afterwards, drying in a hopper at temperatures of 100 to 130 ° C and a residence time of 3 to 6 hours is required.

The triclosan can either be metered in during the raw material production or only in the extruder used during the film production. It is preferably added as a master batch. For this purpose, it is predispersed in a solid carrier material. The carrier materials for the masterbatch are the thermoplastic itself (for example polyethylene terephthalate) or other polymers which are sufficiently compatible with the thermoplastic. The proportion of antimicrobial active ingredient in the masterbatch is generally 0.4 to 30% by weight, preferably 0.8 to 15% by weight, in each case based on the weight of the thermoplastic. It is important that the grain size and bulk density of the respective masterbatch are similar the grain size and the bulk density of the thermoplastic, so that a homogeneous distribution and thus a high transparency of the film is achieved.

According to known processes, the polyester films can be made from a polyester raw material, optionally further raw materials as well as the triclosan and / or other conventional additives (the latter in a customary amount of 0.1 to a maximum of 10 wt - Films are produced with the same or different surfaces.

The polyester film according to the invention is preferably produced by an extrusion process in which the melted polyester material is extruded through a slot die and quenched as a largely amorphous pre-film on a cooling roll. This film is then heated again and in the longitudinal direction and then in the transverse direction or in the transverse direction and then in the longitudinal direction or in the longitudinal direction

Stretched crosswise and again in the longitudinal direction and / or transverse direction. The stretching temperatures are generally 10 to 60 ° C. above the glass transition temperature Tg of the film material, the stretching ratio of the longitudinal stretching is usually 2 to 6, in particular 3 to 4.5, that of the transverse stretching is 2 to 5, in particular 3 to 4, 5, and that of the second carried out if necessary

Longitudinal stretching at 1, 1 to 3. The first longitudinal stretching can also be carried out simultaneously with the transverse stretching (simultaneous stretching). The stretching is followed by the heat setting of the film at oven temperatures of 200 to 280 ° C, in particular at 220 to 270 ° C. The film is then cooled and wound up.

Due to the surprising combination of excellent properties and the antimicrobial effect, the film according to the invention is outstandingly suitable for a large number of different applications, for example for goods in the medical field, in the packaging sector, as a laminating medium, for short-lived

Article - e.g. B. in exhibition stand construction or in advertising - and as a film in waste disposal area to name a few. It can also be used as a packaging film, for example for packaging chilled or frozen goods, or as a furniture film. UV-stabilized and / or flame-retardant films are particularly suitable for indoor or outdoor applications, in the electrical industry or in the construction sector, for greenhouses, roofing, external cladding or covers. The film is easily recyclable without loss of mechanical properties and without environmental pollution.

The invention is explained in more detail below on the basis of exemplary embodiments, without being restricted thereto. The individual properties were tested as follows:

Antimicrobial effect

The film according to the invention and a non-antimicrobial reference film were examined in a shell test. It was the one to be checked

Foil is placed on the nutrient agar in a petri dish and then very thinly covered with agar, in which escherichia coli NCTC 8196 was used as test culture. If there was no active substance against the organism, the test organism grew on the film sample and thus the entire surface of the petri dish. The antimicrobial film was not overgrown by the test culture and the growth around the film was inhibited.

surface gloss

The surface gloss was measured at a measuring angle of 20 ° according to DIN 67530.

yellowness

The yellowness index (YID) is the deviation from the colorlessness in the "yellow" direction and was measured in accordance with DIN 6167. Light transmission (transparency)

Under the light transmission is the ratio of the total let through

To understand light to the incident amount of light.

cloudiness

Haze is the percentage of the transmitted light that deviates by more than 2.5 ° on average from the incident light beam. The image sharpness was determined at an angle of less than 2.5 °.

Light transmission and haze were measured using the "© Hazegard plus" measuring device

ASTM D 1003 measured.

surface defects

Possible surface defects were determined visually.

Mechanical properties

The modulus of elasticity, the tensile strength and the elongation at break were measured in longitudinal and

Transverse direction measured according to ISO 527-1-2.

Standard viscosity (SV) and intrinsic viscosity (IV):

The standard viscosity SV - based on DIN 53726 - was measured as a 1% solution in dichloroacetic acid (DCE) at 25 ° C. SV (DCE) = (η _rel -1) x 1000. The intrinsic viscosity (IV) is calculated as follows from the standard viscosity (SV)

IV (DCE) = 6.67 ^■ 10 ^"4 SV (DCE) + 0.118

Weathering (both sides), UV stability

The UV stability was tested according to the test specification ISO 4892 as follows:

fire behavior

The fire behavior was determined according to DIN 4102 part 2, building material class B2 and according to DIN 4102 part 1, building material class B1 and according to UL test 94.

Determination of the sealing start temperature (minimum sealing temperature) With the sealing device HSG / ET from Brugger, heat-sealed samples were obtained

(Sealing seam 20 mm x 100 mm), the film being sealed at different temperatures with the help of two heated sealing jaws at a sealing pressure of 2 bar and a sealing time of 0.5 s. Test strips 15 mm wide were cut from the sealed samples. The T-seal strength was measured as in the determination of the seal strength. The seal start temperature is the temperature at which a seal seam strength of at least 0.5 N / 15 mm is achieved.

Seal seam strength To determine the seal seam strength, two 15 mm wide strips of film were placed on top of each other and sealed at 130 ° C, a sealing time of 0.5 s and a sealing pressure of 2 bar (device: Brugger type NDS, one-sided heated sealing jaw). The seal seam strength was determined by the T-Peel method. All films were weathered on both sides with the Atlas Ci 65 Weather Ometer from Atlas according to the test specification ISO 4892 on both sides and then tested for mechanical properties, discoloration, surface defects, haze and gloss.

Examples

The examples and comparative examples below are single- or multi-layer, transparent films of different thicknesses, which were produced on an extrusion line.

example 1

From a mixture of

48% by weight of polyethylene terephthalate (RT 49, KoSa, Germany), 2% by weight of a masterbatch made of 90% by weight of PET (RT 49) and 10% by weight

Triclosan, and 50% by weight polyester regenerate (inherent in film production; in addition to PET also contained small amounts of triclosan)

a monofilm with a thickness of 50 μm was produced.

The polyethylene terephthalate RT49 (clear raw material) from which the transparent film was produced had a standard viscosity SV (DCE) of 810, which corresponds to an intrinsic viscosity IV (DCE) of 0.658 dl / g.

The longitudinal stretching ratio set during film production was 3.2 and the transverse stretching ratio was 3.7. The film was then heat set at 235 ° C for about 2 seconds. Example 2

A transparent, three-layer A-B-A film with a total thickness of 12 μm was produced by coextrusion and subsequent stepwise orientation in the longitudinal and transverse directions. The

Base layer B (12 μm) made from a mixture of

50% by weight PET (type 4020, KoSa, Germany) and

50% by weight of regrind (inherent in film production; in addition to PET also contained small amounts of pigment and triclosan from the

Facings)

while the outer layers A (each 1 μm) were produced from a mixture of

83% by weight PET (type 4020),

10% by weight of triclosan masterbatch (as in Example 1) and 7% by weight of a masterbatch which, in addition to PET, contained 10,000 ppm of SiO ₂ pigment ( ^® Sylobloc from Grace).

The PET from which the transparent film was produced had a standard viscosity SV (DCE) of 770, which corresponds to an intrinsic viscosity IV (DCE) of 0.632 dl / g

The longitudinal stretching ratio set during film production was 4.2%

Transverse stretch ratio 3.9. The film was then heat set at 240 ° C for about 2 seconds. Example 3

As described in Example 2, a 12 μm thick A-B-A film was produced, this time the base layer also being antimicrobially treated with triclosan and both sides of the film additionally being coated.

The base layer B was made from a mixture of

48% by weight of polyethylene terephthalate (type 4020)

2% by weight of a masterbatch composed of 90% by weight of PET and 10% by weight of triclosan and

50% by weight of regrind (inherent in film production; in addition to PET also contained small amounts of pigment and triclosan).

The cover layers A were each produced from a mixture of

90% by weight of polyethylene terephthalate (type 4020),

3% by weight of a masterbatch of 90% by weight of PET and 10% by weight of triclosan and 7% by weight of a masterbatch which, in addition to PET, contained 10,000 ppm of SiO ₂ pigment (Sylobloc).

After the longitudinal stretching, the film was coated on both sides with an aqueous dispersion using the “reverse gravure-roll coating” method. The dispersion contained water

4.2% by weight of hydrophilic polyester (containing 5-Na-sulfoisophthalic acid

PET / I PA polyester, SP41, Ticona, USA), 0.15 wt .-% colloidal silica (Nalco ^® 1060, German Nalco Chemical, Germany) as an antiblocking agent and 0.15 wt .-% ammonium carbonate (Merck, Germany) as a pH buffer. The wet application weight was 2 g / m ² per coated side. After the transverse stretching, the calculated thickness of the coating was 40 nm.

Comparative Example 1

Example 2 was repeated with the only difference that this time the film was not antimicrobially treated with triclosan.

The properties of the films according to Examples 1 to 3 and Comparative Example 1 are summarized in Table 1 below:

Table 1

++ = very good = bad nb = not coated Example 4

First of all, a 50 μm thick, transparent monofilm was produced, the main ingredient being PET, alongside 0.2% triclosan and 0.1% Si0 ₂ pigment (antiblocking agent, ^® Sylobloc from Grace, Germany). 30% of the film raw material consisted of the self-generated material that is inherent in the film production.

Triclosan was added in the form of a master batch of 90% PET and 10% triclosan. The Si0 ₂ pigment was also added in the form of a master batch of PET and 10,000 ppm pigment. The polyethylene terephthalate (clear raw material) from which the transparent film was produced had a standard viscosity SV (DCE) of 810, which corresponds to an intrinsic viscosity IV (DCE) of 0.658 dl / g.

The longitudinal stretching ratio set during film production was 3.2 and the transverse stretching ratio was 3.7. The film was then heat set at 235 ° C for about 2 seconds.

After the longitudinal stretching, the film was coated on both sides with an aqueous dispersion by means of a "reverse gravure-roll coating" process. The dispersion contained water

4.20% hydrophilic polyester (5-Na-sulfoisophthalic acid-containing PET /

I PA polyester, SP41, Ticona, USA), 0.15% colloidal silicon dioxide ( ^® Nalco 1060, Deutsche Nalco Chemie, Germany) as an antiblocking agent and

0.15% ammonium carbonate (Merck, Germany) as a pH buffer.

The wet application weight was 2 g / m ² per coated side. After the transverse stretching, the calculated thickness of the coating was 40 nm. Example 5

As described in Example 4, a 50 μm thick monofilm was produced, but this time the film was 0.6% 2- (4,6-diphenyl- [1,3,5] triazin-2-yl) -5-hexyloxyphenol ( ^® Tinuvin 1577 from Ciba-Geigy) as UV stabilizer, based on the total weight of the film. The UV stabilizer was in the form of a 20%

Masterbatches added. The stabilizer has a melting point of 149 ° C and is thermally stable up to approx. 330 ° C.

EXAMPLE 6 A 19 μm thick, three-layer, antimicrobially equipped, transparent film with a layer sequence ABA was produced by coextrusion. The base layer B had a thickness of 16 μm and contained PET as the main component, in addition 4% methanephosphonic acid bis- (5-ethyl-2-methyl-2-oxo-2λ ⁵ - [1, 3.2] dioxaphosphinane-5- ylmethyl ester) (Amgard ^® P1045 from Albright & Wilson) as a flame retardant and 0.2% pentaerythritol tetrakis [3- (3,5-di-TETF-butyl-4-hydroxy-phenyl) -propionatals hydrolysis stabilizer. Flame retardants and stabilizers were added in the form of a masterbatch made from 79% PET, 20% flame retardants and 1% hydrolysis stabilizer. Layer B also contained 30% of the self-regenerated material inherent in film production.

In addition to PET, the _two 1.5 μm thick outer layers A also contained 0.7% triclosan and 0.1% Si0 ₂ pigment ( ^® Sylobloc) as antiblocking agents. The triclosan was added in the form of a master batch of 90% PET and 10% triclosan. The PET was identical to that in Example 4 (same SV and IV).

Example 7

As described in Example 6, an antimicrobial ABA film with a thickness of 19 μm was produced. In contrast to this, however, the film was coated on one side with an aqueous dispersion which was identical to that in Example 4 by "reverse gravure-roll coating" The wet application weight was likewise 2 g / m ² and the calculated thickness of the coating after the transverse stretching was 40 nm.

Example 8

An antimicrobial, sealable, transparent A-B-C film with a thickness of 12 μm was produced. The base layer B had a thickness of 10 μm and contained PET, 0.2% triclosan and 30% self-regenerate as the main constituent. The triclosan was again metered in as a masterbatch (composition as in Example 4).

For the 1 μm thick sealable cover layer A, a copolyester of 78 mol% ethylene terephthalate and 22 mol% ethylene isophthalate was used as the thermoplastic (produced by transesterification in the presence of a manganese catalyst, Mn concentration: 100 ppm). It also contained 3.0% of a masterbatch composed of 97.75% copolyester and 1.0% of a synthetic Si0 ₂ pigment ( ^® Sylobloc 44H from Grace) and 1.25% pyrogenic Si0 ₂ ( ^® Aerosil TT 600 from Degussa AG) as an antiblocking agent.

The 1 μm thick top layer C contained, besides PET, 0.7% triclosan and 3.0% of a Si0 ₂ pigment masterbatch of the same composition as that used for layer A.

The PET from which the transparent film was produced was identical to that in Example 4.

Example 9

As described in Example 8, a 12 μm thick, antimicrobial, transparent, coextruded, sealable ABC film was produced. In contrast to Example 8, the non-sealable top layer C was coated on one side with an aqueous dispersion after the longitudinal stretching by "reverse gravure-roll coating". The dispersion had the same composition as in Example 4. The wet application weight was 2 g / m ² . After the transverse stretching, the calculated thickness of the coating was 40 nm.

Example 10 As described in Example 9, a 12 μm thick, antimicrobial, transparent, coextruded, sealable A-B-C film was produced, which was additionally coated on the top layer C with the adhesion promoter SP41.

In contrast to the film from example 9, the base layer B contained 1.5% solvent blue 35 ( ^® Sudan blue 2 from BASF AG, Germany). The colorant is in

Formed into a masterbatch that contains 20% of the blue colorant in addition to PET.

Example 11 As described in Example 10, a 12 μm thick, antimicrobial, transparent, coextruded, colored, sealable A-B-C film was produced. In contrast to Example 10, the film remained uncoated.

The film was corona treated on top layer C. The intensity was chosen so that the surface tension after the treatment was more than 45 mN / m.

Example 12

Analogously to Example 5, a 50 μm thick monofilm was produced which was antimicrobially treated with 0.2% triclosan, which was metered in in the form of a 10% masterbatch.

As in Example 5, the film to improve the UV stability contained 0.6% UV stabilizer (2- (4,6-diphenyl- [1,3,5] triazin-2-yl) -5-hexyloxyphenol, ^® Tinuvin 1577). The UV stabilizer was added in the form of a 20% master batch. The film also contained 0.2% of the hydrolysis stabilizer described in Example 6 and 4% of the flame retardant also described in this example. The hydrolysis stabilizer and flame retardant were metered in in the form of a masterbatch (composition as in Example 6).

The film also contained 5% solvent blue 35. The colorant was metered in in the form of a masterbatch which, in addition to PET, contained 20% by weight of the blue colorant.

After the longitudinal stretching, the film was coated on both sides with the aqueous dispersion already described in Example 4 by "reverse gravure-roll coating". The wet application weight was 2 g / m ² per coated side. After the transverse stretching, the calculated thickness of the coating was 40 nm.

Example 13

A 50 μm thick, coextruded film with the layer sequence A-B-C was produced.

The formulation of the 47 μm thick base layer B corresponded to the formulation of the monofilm from Example 12, so it contained, in addition to PET triclosan, UV stabilizer,

Flame retardant, hydrolysis stabilizer and soluble dye.

The formulation of the 1.5 μm thick outer layers A and C corresponds to the formulation from Example 8.

As in Example 12, the top layer C was coated with the SP41 adhesion promoter.

Comparative Example 2

As described in Example 4, a 50 μm thick transparent monofilm was produced. In contrast to Example 4, the film did not contain triclosan, so it was not antimicrobial. The film was coated on both sides as in Example 4. The properties of the films according to Examples 4 to 13 (B4 to B13) and Comparative Example 2 (VB 2) are summarized in the table below.

After 1000 hours of weathering per side with Atlas Ci 65 Weather Ometer, the PET films from Examples 5, 12 and 13 equipped with UV stabilizer showed hardly any changes in properties. After 1000 hours of weathering per side with Atlas CI 65 Weather Ometer, the films from the other examples and Comparative Example 2 showed cracks and embrittlement on the surfaces. A precise property profile - especially the mechanical properties - could therefore no longer be measured. The also showed

Film a visually visible yellowing.

Table 2

Claims

claims

1. Single or multi-layer, transparent, biaxially oriented and heat-set, partially crystalline film with a crystallizable thermoplastic as the main component, characterized in that the film or at least one

Layer therein an antimicrobially effective amount of 2,4,4 ^{^{'trichloro-2'}} - hydroxy-diphenyl ether (Triclosan) has.

2. Film according to claim 1, characterized in that the proportion of triclosan 0.01 to 10 wt .-%, preferably 0.1 to 5 wt .-%, each based on the total weight of the single-layer film or the relevant layer the multilayer film.

3. Film according to claim 1 or 2, characterized in that it has a thickness of 1 to 500 microns, preferably 5 to 250 microns, particularly preferably 10 to 100 microns.

4. Film according to one or more of claims 1 to 3, characterized in that the crystallizable thermoplastic has a standard viscosity SV of 600 to 1,000, preferably 700 to 900, each determined according to DIN 53728 in dichloroacetic acid.

5. Film according to one or more of claims 1 to 4, characterized in that it has a haze of less than 30%, preferably less than 25%, each determined according to ASTM D 1003.

6. Film according to one or more of claims 1 to 5, characterized in that it has a gloss of more than 100, preferably more than 110, each determined in accordance with DIN 67530 (measuring angle 20 °).

7. Film according to one or more of claims 1 to 6, characterized in that it is multilayer and has a structure A-B-A or A-B-C, B being the core or base layer and A and C covering layers.

8. Film according to claim 7, characterized in that only the core or base layer is antimicrobial.

9. Film according to one or more of claims 1 to 8, characterized in that it is coated on one or both sides, the coating preferably having a thickness of 5 to 100 nm.

10. Film according to one or more of claims 1 to 9, characterized in that it contains, in addition to triclosan, at least one other antimicrobial compound, preferably 10,10'-oxy-bisphenoxarsin, N-tri-halogenomethylthio-phthalimide, diphenylantimony-2- ethyl hexanoate, copper 8-hydroxy-quinoline, tributyltin oxide or a derivative thereof and / or a derivative of a halogenated diphenyl ether compound, a derivative of 2,4,4'-trichloro-2-hydroxy-diphenyl ether (triclosan) being particularly preferred.

11. Film according to one or more of claims 1 to 10, characterized in that the crystallizable thermoplastic is a crystallizable homopolymer, a crystallizable copolymer, a crystallizable compound or a crystallizable recyclate.

12. Film according to one or more of claims 1 to 11, characterized in that the crystallizable thermoplastic is a polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), bibenzene-modified polyethylene terephthalate (PETBB), bibenzolmo- is differentiated polybutylene terephthalate (PBTBB) or bibenzene-modified polyethylene naphthalate (PENBB).

13. Film according to one or more of claims 1 to 12, characterized in that the proportion of at least one crystallizable

Thermoplastics is 50 to 99% by weight, preferably 75 to 95% by weight, in each case based on the total weight of the film or the total weight of the layer in the film.

14. Film according to claim 1, characterized in that the film against UV

Radiation stabilized, flame retardant, coated on one or both sides, sealable and / or corona or flame treated.

15. Film according to one or more of claims 1 to 14, characterized in that at least one layer therein contains a UV stabilizer.

16. Film according to claim 15, characterized in that the UV stabilizer 2- (4,6-diphenyl- [1,3,5] triazin-2-yl) -5-hexyloxyphenol, 2,2 ^' - Methylene-bis- [6-benzotriazol-2-yl-4- (1, 1, 2,2-tetramethyl-propyl) phenol] or 2,2 ^' - (1, 4-

Phenylene) bis - [[3,1] benzoxazin-4-one].

17. A film according to claim 15 or 16, characterized in that the proportion of the UV stabilizer is 0.1 to 5.0 wt .-%, preferably 0.5 to 3.0 wt .-%, each based on the Total weight of at least one

Layer.

18. Film according to one or more of claims 1 to 22, characterized in that at least one layer contains a flame retardant therein.

19. A film according to claim 18, characterized in that the flame retardant is a bromine compound, a chlorinated paraffin or another chlorine compound, antimony trioxide, aluminum hydroxide or an organic phosphorus compound.

20. Film according to claim 18 or 19, characterized in that the proportion of the flame retardant 0.5 to 30.0 wt .-%, preferably 1.0 to 20.0 wt .-%, each based on the weight of the layer of crystallizable thermoplastics.

21. Film according to one or more of claims 1 to 20, characterized in that it is colored transparently with a dye soluble in the thermoplastic.

22. A film according to claim 21, characterized in that the proportion of the soluble dye is 0.01 to 20.0% by weight, preferably 0.05 to 10.0% by weight, in each case based on the weight of the crystallizable thermoplastic, is.

23. Film according to one or more of claims 1 to 22, characterized in that it comprises a sealable cover layer.

24. Film according to one or more of claims 1 to 23, characterized in that it has an additional coating on at least one side, the thickness of which is preferably 5 to 100 nm, particularly preferably 20 to 70 nm.

25. A method for producing the film according to one or more of claims 1 to 24, characterized in that the melted polyester material is extruded through a slot die, which ent- standing pre-film is quenched on a cooling roll, then stretched in the longitudinal and / or transverse direction and finally heat-set.

26. The method according to claim 25, characterized in that the stretching temperature is 10 to 60 ° C above the glass transition temperature Tg of the film material, the stretching ratio of the longitudinal stretching 2 to 6, preferably 3 to

4.5, that of the transverse stretching is 2 to 5, preferably 3 to 4.5, and that of an optionally carried out second longitudinal stretching is 1, 1 to 3.

27. The method according to claim 25 or 26, characterized in that the thermoplastic soluble dye, the UV stabilizer, the additional antimicrobial compound, the hydrolysis stabilizer and / or the flame retardant are added in the form of at least one masterbatch before the extrusion.

28. The method according to claim 27, characterized in that the masterbatch is pre-dried and / or pre-crystallized.

29. The method according to claim 25, characterized in that an additional coating is applied by "reverse gravure-roll coating".

30. Use of the film according to one or more of claims 1 to 24 in indoor and outdoor use, in the electronics industry or in the construction sector, for greenhouses, roofs, outer cladding or covers, as a film especially for chilled or frozen goods, as a furniture film, in exhibition stand construction or in advertising (especially for illuminated advertising profiles) as well as in general in the medical field as well as in the packaging and disposal area.