DE10043779A1 - Multi-layered film useful e.g. in displays or protective glazing, comprises bibenzene-modified thermoplastic and a covering layer - Google Patents

Abstract

Multilayered film (A) comprises: (1) a base layer (A1), the main component of which is a crystallizable, 'bibenzene'-modified thermoplastic (I); and (2) at least one covering layer (A2) that is a mixture, or blend, of two components (1, 2) and has at least one additional functionality. Independent claims are also included for the following: (1) method for preparing (A); and (2) shaped objects prepared from (A).

Description

The invention relates to a biaxially oriented film which has a base layer which contains at least 50% by weight of a bibenzene-modified thermoplastic, and has at least one matt cover layer, which is a mixture or a blend contains two components I and II. The film is inherently UV stable and shows at least one additional functionality. The invention further relates to a Process for producing the film and its use.

Component I of the mixture or blend is preferably a Polyethylene terephthalate homopolymer or polyethylene terephthalate copolymer or a mixture of polyethylene terephthalate homo- and / or copolymers.

Component II of the mixture or blend is preferably a Polyethylene terephthalate copolymer, which preferably from the condensation product of the following monomers or their derivatives capable of forming polyesters consists of: isophthalic acid, aliphatic dicarboxylic acid, sulfomonomers, the one Metal sulfonate group on the aromatic part of an aromatic dicarboxylic acid has and aliphatic or cycloaliphatic glycol.

The top layer according to the invention is characterized by a characteristic matt Surface or optics and is particularly suitable for use as Packaging film or well suited for applications in the industrial sector where in particular UV protection or non-permeability of the UV light is required becomes.

Films made of crystallizable thermoplastics with a thickness between 1 and 500 microns known. These foils are not inherently UV stable, so neither the foils nor the articles made from it are suitable for outdoor use. at  Outdoor applications, these films show yellowing and after a short time a deterioration in mechanical properties due to a photooxidative Degradation by sunlight. The foils are also not flame retardant, which makes them unsuitable for areas where high flame retardancy is required. The films are also insufficiently sealable.

The industry has a high need for transparent, high-gloss Plastic films, such as B. biaxially oriented polypropylene or biaxially oriented Polyester films. In addition, there is an increasing need for such foils, where there is protection against ultraviolet radiation and at least where a surface layer is not high-gloss, but stands out through distinguishes characteristic matt appearance and thereby z. B. the Packaging a particularly attractive and therefore effective advertising appearance at the same time provides protection against UV radiation.

No. 4,399,179 describes a coextruded biaxially oriented polyester film described, which consist of a transparent base layer and at least one matt Layer consists essentially of a certain Polyethylene terephthalate copolymer exists and also inert particles with a Contains diameter from 0.3 to 20 microns in a concentration of 3 to 40 wt .-%. The special copolymer is a processing aid through which the viscosity of the melt containing inert particles is reduced, so that a flawless Extrusion of this layer is possible. The mattness of the film is increased by adding the inert particles reached in the corresponding layer.

EP 0 144 978 describes a self-supporting oriented film made of thermoplastic Described plastic, which one on at least one of its two surfaces continuous polyester coating that acts as an aqueous dispersion on the film is applied before the last stretching step. The polyester coating consists of a condensation product of various monomers that are used to form  Are capable of polyesters, such as isophthalic acid, aliphatic dicarboxylic acids, Sulfomonomers and aliphatic or cycloaliphatic glycols.

EP-A 0 620 245 describes films made of polyethylene terephthalate, which are improved in terms of their thermal stability. These slides included Antioxidants which are suitable for trapping radicals formed in the film and break down formed peroxide. A proposal on how the UV stability of such films there is no need to improve this document.

DE 198 23 991 describes amorphous plates which contain a bibenzene-modified polyalkylene terephthalate and / or a bibenzene-modified polyalkylene naphthalate as the main constituent. These plates are 0.1 to 20 mm thick, amorphous, ie not crystalline, undrawn and unoriented. The plates are particularly characterized by good mechanical properties in a wide temperature range. Under good mechanical properties is understood to mean that in the measurement of impact strength a _n Charpy (ISO 179 / 1D), no breakage occurs and that the Izod impact strength according to ISO 180 at -40 ° C preferably in the range from 10 to 140 kJ / m ² lies. The amorphous plates described are produced using smoothing calender technology and by freezing below the glass transition temperature by means of cooling and smoothing.

DE OS 23 46 787 describes a flame-retardant raw material. In addition to the raw material, its use for the production of films and fibers is also claimed. The following deficits emerged in the production of a film from this phospholane-modified raw material:

• - The raw material is very sensitive to hydrolysis and must be pre-dried very well become. When drying the raw material with dryers that are state of the art Technique correspond, the raw material glues, so that only under the most difficult Conditions a film can be produced.
• - The films produced in this way become brittle when exposed to temperature, i.e. H. the mechanical properties deteriorate due to embrittlement, so  that the film becomes unusable. Already occurs after 48 h of thermal stress this embrittlement.

GB-A 1 465 973 describes a coextruded, two-layer polyester film described, the one layer of isophthalic and copolyesters containing terephthalic acid and their other layer There is polyethylene terephthalate. About the sealing behavior of the film can be found in the Font no usable information. Due to the lack of pigmentation, the film is not Can be produced reliably (film cannot be wound) and only with restrictions further processed.

EP 0 035 835 describes a coextruded, sealable polyester film which to improve the winding and processing behavior in the sealing layer Particles are added whose average particle size is the layer thickness of the Sealing layer exceeds. Due to the particulate additives Surface protrusions formed that prevent unwanted blocking and sticking to rollers or prevent tours. Over the other, non-sealable layer of the film, no further details are given on the incorporation of antiblocking agents. It It remains open whether this layer contains antiblocking agents. By choosing particles with larger diameter than the thickness of the sealing layer and in the in the examples specified concentrations, the sealing behavior of the film deteriorates. The script does not give any information on the sealing temperature range of the film. The seal seam strength is measured at 140 ° C and is in a range of 63 up to 120 N / m (0.97 N / 15 mm to 1.8 N / 15 mm film width).

EP 0 432 886 describes a coextruded multilayer polyester film which has a first surface on which a sealable layer is arranged and which has a second surface on which an acrylate layer is arranged. The sealable top layer can also be made of isophthalic acid and copolyesters containing terephthalic acid. Thanks to the coating on the back the film gets an improved processing behavior. Sealing area information  the film is not made in the script. The seal seam strength is at 140 ° C measured. For an 11 µm thick sealing layer, a sealing seam strength of 761.5 N / m (11.4 N / 15 mm). A disadvantage of the acrylic coating on the back is that this side no longer seals against the sealable top layer. The foil can only be used to a limited extent.

EP 0 515 096 describes a coextruded, multilayer, sealable polyester film described, which contains an additional additive in the sealable layer. The Additive can e.g. B. contain inorganic particles and is preferably in a aqueous layer applied to the film during its manufacture. This is supposed to Foil maintain the good sealing properties and be easy to process. The Back contains very few particles that are mainly in the regranulate get this layer. Information on the sealing temperature range of the film is also given not made in this writing. 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 sealing layer one Seal seam strength of 275 N / m (4.125 N / 15 mm) specified.

WO 98/06575 describes a coextruded multilayer polyester film which has a sealable top layer and a non-sealable base layer. The The base layer can be constructed from one or more layers, the interior of the layers is in contact with the sealable layer. The other (outer) Layer then forms the second non-sealable top layer. The sealable The top layer can also consist of isophthalic acid and terephthalic acid There are copolyesters that do not contain antiblocking particles. The slide contains also at least one UV absorber, which is the base layer in one Weight ratio of 0.1 to 10% is added. As a UV absorber preferably triazines, e.g. B. Tinuvin® 1577 from Ciba. The base layer is equipped with common antiblocking agents. The film is characterized by a good one Sealability, but does not have the desired processing behavior and exhibits also deficits in the optical properties (gloss and cloudiness).  

In the cases described there is no evidence of how a film at least on a film surface a low gloss with a high gloss Transparency of the film and how the film at the same time sufficient UV can be stabilized.

The object of the present invention was therefore to provide a film with at least one matt surface and with at least one additional functionality to provide the simple and economical to manufacture, the good has physical properties of the known films, none Disposal problems caused and especially by the absorption of UV Light and characterized by a high inherent UV stability.

Additional functionality means that the film according to the invention is flame-retardant and / or is equipped with additional UV stabilizers and / or is sealable and / or is coated on one or both surfaces and / or on one or is corona treated on both sides.

A high inherent UV stability means that the films are exposed to sunlight or other UV radiation are not or only extremely little damaged, so that the Films are suitable for outdoor applications and / or critical indoor applications.

In particular, the films should not yellow when used outdoors for several years, show no embrittlement or cracking on the surface and also none Have deterioration in mechanical properties. High UV stability means that the film absorbs UV light and light only in the visible Area lets through.

The good mechanical properties preferably include a high modulus of elasticity (E _MD <3200 N / mm ² ; E _TD <3500 N / mm ² ) and good tensile strength values (in MD <100 N / mm ² ; in TD <130 N / mm ² ).

Good stretchability includes e.g. B. that the film in its manufacture excellent in both longitudinal (MD) and transverse (TD) directions and without breaks can orient.

The task is solved by a coextruded and biaxially oriented film The type according to the invention is inherently UV-stable and can additionally flame retardant and / or equipped with additional UV stabilizers and / or is sealable and / or is coated on one or both surfaces and / or is corona treated on one or both sides.

Component I of the mixture or blend is preferably a Polyethylene terephthalate homopolymer or polyethylene terephthalate copolymer or a mixture of polyethylene terephthalate homo- and / or copolymers.

Component II of the copolymer or of the mixture or of the blend is preferably a polymer containing at least one sulfonate group, in particular a condensation product of the following monomers or their derivatives capable of forming polyesters:

• A) 65 to 95 mol% isophthalic acid;
• B) 0 to 30 mol% of at least one aliphatic dicarboxylic acid with the formula HOOC (CH ₂ ) _n COOH,
  where n ranges from 1 to 11;
• C) 5 to 15 mol% of at least one sulfomonomer containing an alkali metal sulfonate group on the aromatic portion of a dicarboxylic acid;
• D) the stoichiometric amount necessary to form 100 mol% condensate a copolymerizable aliphatic or cycloaliphatic glycol with 2 up to 11 carbon atoms;

where the percentages are based on the total amount of Monomers forming component II.  

Mechanical mixtures are among mixtures for the purposes of the present invention to understand which are made from the individual components. In general For this purpose, the individual components as pressed molded articles of small size, for. B. lenticular or spherical granules, poured together and with a suitable Vibrating device mechanically mixed. Another way for that Creation of the mixture consists in that the respective components I and II in Granulate form separately for the extruder for the invention Cover layer are fed and the mixture in the extruder, or in the subsequent melt-carrying systems is carried out.

A blend in the sense of the present invention is an alloy-like composite of individual components I and II, which are no longer in the original components can be disassembled. A blend has properties like a homogeneous substance and can be characterized accordingly by suitable parameters.

According to the invention, the film has at least two layers. It then comprises layers a layer B (= base layer) and the matt cover layer A according to the invention. In In a further preferred embodiment of the invention, the film has three layers built up and has on one side of layer B the top layer A and on the another side of layer B on another layer C. In this case, the both layers A and C are the outer layers, which can be the same or different.

The film according to the invention contains as a main component, at least in the Base layer, a crystallizable, bibenzol-modified thermoplastic. suitable are crystallizable or partially crystalline bibenzol-modified thermoplastics for example polyesters such as bibenzene-modified polyethylene terephthalate (PETBB), Bibenzol-modified polybutylene terephthalate (PBTBB), bibenzol-modified Polyethylene naphthalate (PENBB), with bibenzene-modified polyethylene terephthalate (PETBB) is preferred.  

According to the invention, bibenzene-modified crystallizable thermoplastics are understood

• Crystallizable bibenzene-modified copolymers,
• - crystallizable bibenzol-modified compounds,
• - Crystallizable bibenzene-modified recyclate and
• - other variations of crystallizable bibenzol-modified thermoplastics.

For the production of the copolymers polyalkylene terephthalate or polyalkylene naphthalate can in addition to the main monomers such. B. dimethyl therephthalate (DMT), Bisbenzenic acid (BB), ethylene glycol (EG), propylene glycol (PG), 1,4-butanediol, Terephthalic acid (TA), and / or 2,6-naphthalene dicarboxylic acid (NDA), too Isophthalic acid (IPA), trans and / or cis-1,4-cyclohexanedimethanol (c-CHDM, t-CHDM or c / t-CHDM) can be used.

The main ingredient is that the amount of bibenzene-modified thermoplastic preferably between 50 and 99.9% by weight, particularly preferably between 75 and 99% by weight is based on the weight of the layers equipped with it. The the remaining amount of 100% can be conventional additives for biaxially oriented films.

Bibenzene-modified polyethylene terephthalate polymers with a crystallite melting point Tm, measured with DSC (differential scanning calorimetry) at a heating rate of 20 ° C./min. from 180 ° C to over 365 ° C, preferably from 180 ° C to 310 ° C, depending on the bibenzenic acid content, with a crystallization temperature range Tc between 75 ° C and 280 ° C, a glass transition temperature Tg between 65 ° C and 130 ° C and with a density, measured according to DIN 53479, of 1.15 to 1.40 g / cm ³ and a crystallinity between 5% and 65%, preferably 20% and 65%, are preferred starting materials for the production of the film according to the invention.

Bibenzene-modified polyethylene naphthalate polymers with a crystallite melting point Tm, measured with DSC (Differential Scanning Calorimetry) at a heating rate of 10 ° C / min. from 120 ° C to 310 ° C, preferably from 140 ° C to 280 ° C, depending on the bibenzenic acid content, with a crystallization temperature range Tc between 75 ° C and 280 ° C, a glass transition temperature Tg between 65 ° C and 120 ° C and with a density, measured according to DIN 53479, of 1.20 to 1.45 g / cm ³ and a crystallinity of between 5% and 65%, preferably 20% and 65%, are preferred starting materials for the production of the film according to the invention.

It is essential to the invention that the bibenzol-modified thermoplastic used is crystallizable. According to the invention, the bibenzenic acid content is preferably between 1 and 50 wt .-%, preferably between 5 and 45 wt .-%, in particular between 10 and 40 wt .-%, based on the weight of the bibenzol-modified thermoplastic. If the bibenzenic acid content is <50% by weight, the film according to the invention is u. U. insufficiently crystallizable after orientation. In this case, the mechanical properties deteriorate significantly.

The standard viscosity SV (DCE) of the bibenzene-modified polyethylene terephthalate, measured in dichloroacetic acid according to DIN 53728, lies between 600 and 1000, preferably between 700 and 900.

The bulk density, measured according to DIN 53466, is preferably between 0.70 kg / dm ³ and 1.0 kg / dm ³ , and particularly preferably between 0.75 kg / dm ³ and 0.90 kg / dm ³ .

At least one cover layer of the multilayer film according to the invention contains an im following mixture or a blend of two components I described and II and optionally additional additives.

Component I of the top layer mixture or of the blend preferably contains such described a thermoplastic polyester. This can be a polyester like it is for the base layer was described in more detail. For the generation of high matt degrees it has  proved to be favorable if the polyester polymer for component I of top layer according to the invention has a relatively low viscosity per se having. A modified one is used to describe the viscosities of the melts Solvent viscosity (SV value) used. For commercially available polyethylene terephthalate The SV values are latex, which are suitable for the production of biaxially oriented films in the range from 500 to 1200. In order to achieve a high mattness of the film in the sense of To get the present invention, it has proven to be beneficial if the SV Value of the polymers for component I of the top layer according to the invention in Range from 500 to 800, preferably in the range from 500 to 750, in particular are preferably in the range from 500 to 700.

As already stated, component II of the top layer mixture is obtained by condensation of the following monomers or their derivatives capable of forming polymers:

• A) isophthalic acid,
• B) optionally an aliphatic dicarboxylic acid,
• C) a sulfomonomer, and
• D) the amount necessary to form 100 mol% condensate aliphatic or cycloaliphatic glycol.

The total acid equivalents present should be essentially on a molar basis correspond to the total glycol equivalents present.

Dicarboxylic acids suitable as component B) of the copolyester are e.g. B. Malon, Adipic, azelaic, glutaric, sebacic, cork, amber and brassylic acid as well Mixtures of these acids or their derivatives capable of forming polyesters. Of the acids mentioned, sebacic acid is preferred.  

Examples of sulfomonomers which have a metal sulfonate group on the aromatic part of an aromatic dicarboxylic acid (component C) are those monomers which correspond to the following general formula:

In this formula is
M is a monovalent cation of an alkali metal,
Z is a trivalent aromatic radical, and
X and Y are carboxyl groups or polyester-forming equivalents.

Monomers of this type are described in US-A 3,563,942 and 3,779,993. Examples of such monomers are sodium sulphoterephthalic acid, sodium 5-sulfoisophthalic acid, sodium sulfophthalic acid, 5- (p-sodium sulfphenoxy) isophthalic acid, 5- (sodium sulfopropoxy) isophthalic acid and the like monomers and their derivatives capable of forming polyesters, such as e.g. , B. the dimethyl ester. M is preferably Na ⁺ , Li ⁺ or K ⁺ .

The term “derivatives capable of forming polyesters” are preferred here Respondents understand with such groups that too Condensation reactions, especially transesterification reactions, to form Are capable of polyester bonds. Such groups include carboxyl groups as well whose lower alkyl esters, e.g. B. dimethyl terephthalate, diethyl terephthalate and numerous other esters, halides or salts. The acid monomers are preferred as Dimethyl ester is used because in this way the condensation reaction is better can be controlled.

Glycols suitable as component D) are e.g. B. ethylene glycol, 1,5-pentadiol, 1,6- Hexanediol, neopentylglycol, 1,10-decanediol, cyclohexane-dimethanol and the like Substances. Ethylene glycol is preferably used.  

The copolyesters can be made by known polymerization techniques. In general, the procedure is such that the acid components with glycol brought together and heated in the presence of an esterification catalyst, with subsequent addition of a polycondensation catalyst.

It has been shown that the relative proportions of components A, B, C and D, which are used to produce the mixtures according to the invention, are decisive for achieving the matt top layer. So z. B. isophthalic acid (Component A) be present at least about 65 mol% as the acid component. Component A is preferably pure isophthalic acid, in an amount of about 70 up to 95 mol% is present.

For component B it applies that any acid with the formula mentioned brings satisfactory results, with adipic acid, azelaic acid, sebacic acid, Malonic acid, succinic acid, glutaric acid and mixtures of these acids are preferred become. The amount is preferably 1 to 20 mol% when component B in the Composition is included.

The glycol component is present in a stoichiometric amount.

The copolyesters suitable for the purposes of the invention continue to stand out preferably characterized in that it has an acid number below 10, preferably from 0 to 3, an average mole weight below about 50,000 and an SV value in the range of about 300 to 700, preferably about 350 to 650.

The ratio (weight ratio) of the two components I and II The top layer mixture or blend can vary within wide limits depends on the intended use of the multilayer film. Preferably lies the ratio of components I and II in a range from I: II = 10:90 to I: II = 95: 5, preferably between I: II = 20: 80 to I: II = 95: 5 and in particular between I: II = 30: 70 to I: II = 95: 5.  

Light, especially the ultraviolet portion of solar radiation, i.e. H. the Wavelength range from 280 to 400 nm, initiates degradation processes with thermoplastics, as a result not only the visual appearance due to color change or yellowing changes, but also the mechanical-physical properties be adversely affected.

The inhibition of these photooxidative degradation processes is of considerable technical and economic importance, since otherwise the application possibilities of numerous thermoplastics are drastically restricted.

Unmodified polyethylene terephthalates, for example, only start below Absorb 360 nm UV light, their absorption takes below 320 nm considerably and is very pronounced below 300 nm. The maximum absorption is between 280 and 300 nm.

In the presence of oxygen there are mainly chain cleavages, but none Networking observed. Carbon monoxide, carbon dioxide and carboxylic acids are the quantitatively predominant photo-oxidation products. In addition to the direct Photolysis of the ester groups still need to consider oxidation reactions that also lead to the formation of carbon dioxide via peroxide radicals to have.

The photooxidation of e.g. B. polyethylene terephthalates can also over Hydrogen elimination in the α-position of the ester groups to form hydroperoxides and their Decomposition products and the associated chain cleavages (H. Day, DM. Wiles: J. Appl. Polym. Sci 16, 1972, page 203).

UV stability can in principle be achieved by adding UV stabilizers become. UV stabilizers, d. H. UV absorbers as light stabilizers are chemical Compounds that are involved in the physical and chemical processes of light Degradation can intervene. Soot and other pigments can partially  Effect sun protection. However, these substances are for transparent films unsuitable as they lead to discoloration or color change. For transparent films only organic and organometallic compounds that are suitable for this stabilizing thermoplastics no or only an extremely low color or Give color change.

UV stabilizers are very expensive, some of them evaporate during film production or migrate over time, so the film e.g. B. after 1 to 2 years unwanted coating shows. This increases the gloss and transparency of the film adversely affected.

In view of the fact that UV stabilizers can offer protection, the person skilled in the art would have used commercially available UV stabilizers. He would have noticed that

• - The UV stabilizer has a lack of thermal stability and at Temperatures decomposed or outgassed between 200 ° C and 240 ° C,
• - Large amounts (approx. 10 to 15% by weight) of UV stabilizer are incorporated so that the UV light is absorbed and the film is not damaged.

At these high concentrations, the film is yellowish or the color has changed after production. Furthermore, the mechanical properties of such a film are adversely affected. Problems arise during stretching such as e.g. B.

• - Demolition due to lack of strength, d. H. Modulus of elasticity,
• - nozzle deposits, which leads to profile fluctuations,
• - Roller deposits from the UV stabilizer, which affects the optical properties (cloudiness, adhesive defect, inhomogeneous surface),
• - Deposits in stretching and fixing frames that drip onto the film.

It was therefore surprising that excellent UV protection could already be achieved by using the bibenzene-modified thermoplastics according to the invention without the addition of UV stabilizers. It was also surprising that this high UV protection

• - The color of the film compared to a non-stabilized film in the context of Measurement accuracy does not change;
• - no outgassing, no nozzle deposits, no frame evaporation set, which gives the film an excellent appearance and a has an excellent profile and flatness;
• - The inherently UV-stabilized film due to its excellent stretchability in Longitudinal and transverse direction, so that they are reliable and stable on so-called high speed film lines with speeds of 420 m / min can be produced reliably. This is the invention Film also economically profitable.

It should also be mentioned that the regenerated material is again used in the production of the film can be used without negatively influencing the color of the film.

In a preferred embodiment, the film according to the invention can still contain additional UV stabilizers.

UV stabilizers suitable as light stabilizers for the purposes of the present invention are UV stabilizers that are soluble in Bibenzol-modified thermoplastics preferably at least 70%, preferably 80%, particularly preferably 90%, of the UV Light in the wavelength range from 180 nm to 380 nm, preferably 280 to 350 nm absorb. These are particularly suitable if they are in the temperature range are thermally stable from 260 to 300 ° C, d. H. do not decompose and not to Outgassing. Suitable UV stabilizers are, for example, 2- Hydroxybenzophenones, 2-hydroxybenzotriazoles, nickel-organic compounds, Salicylic acid esters, cinnamic acid ester derivatives, resorcinol monobenzoates, oxalic acid anilides, Hydroxybenzoic acid esters, sterically hindered amines, benzoxazinones and triazines, the 2-hydroxybenzotriazoles and the triazines being preferred. It can too Mixtures of UV stabilizers are used.  

The UV stabilizer or stabilizers are preferably contained in the cover layers. at The base layer and any existing intermediate layers with UV Stabilizer must be equipped.

It was surprising that the use of the above UV stabilizers in Combination with the inherently UV-stable thermoplastic in films into one more led to better UV protection.

In a very particularly preferred embodiment, the film according to the invention contains 0.01% by weight to 5.0% by weight of 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- ( hexyl) oxy phenol of the formula

or 0.01% to 5.0% by weight of 2,2-methylene-bis (6- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) - phenol of the formula

or 0.01% to 5.0% by weight of 2,2 '- (1,4-phenylene) to [4H-3,1-benzoxazin-4-one]

In a preferred 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 Light stabilizers are preferably between 0.01% by weight and 5.0% by weight, based on the weight of the layers equipped with it.

The films according to the invention can additionally be flame-retardant, d. H. they then contain at least one flame retardant or mixtures various flame retardants. The flame retardant is preferred in the Base layer included, but can also in all or only in individual film layers (e.g. in the cover and / or intermediate layers).

A flame retardant effect means that the film according to the invention in one so called fire protection test the requirements according to DIN 4102 part 2 and especially meets the requirements of DIN 4102 Part 1 and in the building material class B2 and in particular B1 of the flame retardant substances can be classified.

Furthermore, the flame-retardant film should meet UL test 94 "horizontal Burning Test for Flammability of Plastic Material "so that it can pass into the class 94 VTM-0 can be classified.

The film according to this embodiment of the invention contains at least one Flame retardant, which is preferred directly via the so-called masterbatch technology is metered in during film production. The concentration of the flame retardant is preferably 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 layers equipped with it. In the Production of the master batch is generally a ratio of Flame retardants for thermoplastic in the range from 60 to 40% by weight to 10 to 90% by weight respected.

Typical flame retardants include bromine compounds, chlorinated paraffins and other chlorine compounds, antimony trioxide, aluminum trihydrates, the Halogen compounds due to u. The resulting halogen-containing by-products can be disadvantageous. Furthermore, the low light resistance is one of them equipped film in addition to the development of hydrogen halide in the event of a fire disadvantageous.

Suitable flame retardants, which are preferably used according to the invention, are, for example, organic phosphorus compounds such as carboxyphosphinic acids, their anhydrides and dimethyl methylphosphonate. It is advantageous if the organic Phosphorus compound is soluble in the thermoplastic, since otherwise the required optical properties u. May not be met.

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

As hydrolysis stabilizers, phenolic stabilizers, alkali / Alkaline earth stearates and / or alkali / alkaline earth carbonates in amounts of preferably 0.01 up to 1.0 wt .-%, based on the weight of the so equipped Layers. Phenolic stabilizers are used in an amount of 0.05 to 0.6% by weight, in particular 0.15 to 0.3 wt .-% and with a molecular weight of more than 500 g / mol prefers. Pentaerythrityl tetrakis-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate or 1,3,5-trimethyl-2,4,6-tris (3,5-di-tertiary-butyl-4-hydroxybenzyl) benzene particularly advantageous. Mixtures of different types can also be used Hydrolysis stabilizers are used.  

In a preferred embodiment, the invention contains heavy flammable film is a crystallizable, bibenzene-modified polyethylene terephthalate, 1% by weight to 20% by weight of an organic phosphorus compound soluble in PETBB as a flame retardant and 0.1% to 1.0% by weight of a hydrolysis stabilizer. Dimethyl methylphosphonate is preferred as the flame retardant.

This information regarding flame retardants and hydrolysis stabilizers also applies with regard to other thermoplastics to be used according to the invention.

Fire protection tests according to DIN 4102 and the UL test are very surprising showed that in the case of a three-layer film, it is quite sufficient that the 0.5 up to 2 mm thick top layers with flame retardants to provide a to achieve improved flame retardancy. If necessary and at high Fire protection requirements can also include the base layer with flame retardant be equipped, d. H. include so-called basic equipment.

In addition, measurements showed that the film of the invention Temperature loads of 100 ° C do not become brittle over a longer period of time.

No embrittlement after temperature exposure means that the film after 100 Hours of annealing at 100 ° C in a forced air oven, no embrittlement and none has adverse mechanical properties.

An economical production includes. B. that the raw materials or Raw material components that are used to manufacture the possibly flame-retardant film are required with commercially available industrial dryers, such as vacuum dryers, Fluidized bed dryer, fluid bed dryer or fixed bed dryer (shaft dryer), can be dried. It is essential that the raw materials do not stick together be thermally degraded. The dryers mentioned work at temperatures between about 100 and 170 ° C, at which those mentioned in the prior art  glue the flame-retardant raw materials and the dryers or extruders can clog that no film production is possible.

The raw material goes through one in the most gently drying vacuum dryer Temperature range from approx. 30 ° C to 130 ° C at a vacuum of 50 mbar. After that is a so-called drying in a hopper at temperatures from 100 to 130 ° C and a residence time of approx. 3 to 6 hours is required. Even here it sticks in the stand raw materials described in technology.

During the production of the film according to the invention, it was also found that preferably using masterbatch technology, a suitable predrying or Precrystallization of the masterbatch and, if necessary, by using small Concentrations of hydrolysis stabilizer without the flame retardant film Can be glued in the dryer. Furthermore, no outgassing and Deposits found in the production process.

Surprisingly, films according to the invention in the thickness range 10-350 μm the requirements of building material classes B2 and B1 according to DIN 4102 and UL test 94.

Where a very good sealability is required and where this property does not have The film according to the invention is an online coating at least three layers and then includes the base layer B as layers, the sealable top layer C and the matt top layer A.

The sealable cover layer applied to base layer B by coextrusion C is preferably based on polyester copolymers and then consists of essentially from copolyesters, predominantly from isophthalic acid, Bibenzolcarboxylic acid and terephthalic acid units and from ethylene glycol units are composed. The remaining monomer units come from others aliphatic, cycloaliphatic or aromatic diols or dicarboxylic acids, such as they can also occur in the base layer. The preferred copolyesters that  provide the desired sealing properties are those which are made from ethylene terephthalate and ethylene isophthalate units are constructed. The proportion of ethylene terephthalate is preferably 40 to 95 mol% and the corresponding proportion of ethylene isophthalate 60 to 5 mol%. Copolyesters in which the proportion of Ethylene terephthalate 50 to 90 mol% and the corresponding proportion Ethylene isophthalate is 50 to 10 mol% and copolyesters are very preferred which the proportion of ethylene terephthalate 60 to 85 mol% and the corresponding proportion of ethylene isophthalate is 40 to 15 mol%.

The desired sealing and processing properties of the inventive film are from the combination of the properties of the for sealable top layer used copolyesters and the topographies of sealable top layer C and the matt top layer A obtained.

A seal starting temperature of preferably less than 110 ° C and one Seal seam strength of at least 1.3 N / 15 mm can be achieved if for the sealable top layer C uses the copolymers described in more detail above become. The best sealing properties of the film are obtained when the copolymer no other additives, especially no inorganic or organic fillers be added. In this case, you get the given copolyester lowest sealing starting temperature and highest sealing seam strengths. In this case, however, the handling of the film deteriorates because of the surface the sealable cover layer A tends to block. The film can be bad wrap and is for further processing at high-speed Packaging machines not suitable. To improve the handling of the film and Processability, it is necessary to modify the sealable top layer C. This is best done with the help of suitable antiblocking agents from a selected one Size that are added to the sealing layer in a certain concentration and in such a way that on the one hand the blocking is minimized and on the other hand the Sealing properties are only slightly deteriorated.  

According to the invention, the film can be coated on at least one of its surfaces, so that the coating on the finished film has a thickness of preferably 5 to 100 nm, preferably 20 to 700 nm, in particular 30 to 50 nm. The coating is preferably applied in-line, ie during the film production process, expediently before transverse stretching. Application by means of the so-called "reverse gravure-roll coating" method, in which the coatings can be applied extremely homogeneously in the layer thicknesses mentioned, is particularly preferred. The coatings are preferably applied as solutions, suspensions or dispersions, particularly preferably as an aqueous solution, suspension or dispersion. The coatings mentioned give the film surface an additional function such. B. the film is sealable, printable, metallizable, sterilizable, antistatic, or they improve z. B. the aroma barrier or allow adhesion to materials that would otherwise not adhere to the film surface (z. B. photographic emulsions). Examples of substances / compositions that add additional functionality are:
Acrylates such as z. B. are described in WO 94/13476, ethyl vinyl alcohols, PVDC, water glass (Na ₂ SiO ₄ ), hydrophilic polyesters (5-Na-sulfoisophthalic acid-containing PET / IPA polyesters as described, for example, in EP-A-0 144 878, US-A-4,252,885 or EP-A-0 296 620, vinyl acetates as described, for example, in WO 94/13481, polyvinyl acetates, polyurethanes, alkali metal 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 The substances / compositions which impart the additional functionality can contain the usual additives, such as antiblocking agents, pH stabilizers in amounts of preferably 0.05% by weight Up to 5 wt .-%, preferably 0.1 wt .-% to 3 wt .-%, wt .-% are each based on the weight of the coating agent (z. B. solution, emulsion, dispersion).

The substances / compositions mentioned are a dilute solution, emulsion or dispersion preferably as an aqueous solution, emulsion or dispersion on a or both film surfaces are applied, and then the solvent volatilized. If the coatings are applied in-line before transverse stretching,  Usually the thermal treatment in the transverse stretching and subsequent is sufficient Heat fixation to volatilize the solvent and the coating too dry. The dried coatings then have preferred layer thicknesses 5 to 100 nm, preferably 20 to 70 nm, in particular 30 to 50 nm.

Furthermore, the films can preferably be coated with metals such as aluminum or ceramic materials such as SiO _x or Al _x O _y in an off-line process. This improves their gas barrier properties in particular.

In another embodiment, the film can also be colored transparently his. For this purpose, the film according to the invention can be soluble in the thermoplastic Contain dye, the concentration of the soluble dye preferably in Range from 0.01% by weight to 20.0% by weight, in particular in the range from 0.05 to 10.0% by weight, based on the weight of the layers equipped with it.

Soluble dyes are substances that are molecular in the polymer are solved (DIN 55949).

The color change of the film is based on the wavelength-dependent absorption and / or scattering of light. Dyes can only absorb light, but not scatter, because a certain particle size is the physical requirement for a Scattering is.

Coloring with dye is a solution process. As The result of this solution process is the dye, for example in the Crystallizable thermoplastics solved. Such coloring is considered transparent, translucent, translucent or opal.

Of the various classes of soluble dyes, the fat and aromatic-soluble dyes are preferred. These are, for example Azo and anthraquinone dyes. They are particularly suitable for. B. for coloring  PET or PETBB, because of the high glass transition temperatures of PET Migration of the dye is restricted. (Literature J. Koerner: Soluble dyes in the plastics industry in "VDI-Gesellschaft Kunststofftechnik:" coloring of Plastics, VDI-Verlag, Düsseldorf 1975).

Suitable soluble dyes are, for example: C.I. Solvent Yellow 93 (a Pyrazolone derivative), C.I. Solvent Yellow 16 (a fat-soluble azo dye), fluorolegreen gold (a fluorescent polycyclic dye), C.I. Solvent Red 1 (an azo dye), Azo dyes such as Thermoplastic Red BS, Sudan Red BB, C.I. Solvent Red 138 (a Anthraquinone derivative), fluorescent benzopyran dyes such as fluorol red GK and Fluorolange GK, C.I. solvent blue 35 (an anthraquinone dye), C.I. solvent blue 15: 1 (a phthalocyanine dye) and many others.

Mixtures of two or more of these soluble dyes are also suitable.

The soluble dye is preferably metered in using masterbatch technology but can also be incorporated directly at the raw material manufacturer. The concentration of Color additives in the masterbatches are preferably between 0.01% by weight and 40% by weight, preferably between 0.05% and 25% by weight, based on the weight of the crystallizable thermoplastics.

The film can also be corona or be flame treated. The treatment intensity is chosen so that the Surface tension of the film is generally over 45 mN / m.

The base layer and the top layers and any intermediate layers that may be present can also contain conventional additives such as stabilizers and antiblocking agents. You are expedient to the polymer or the polymer mixture before Melt added. As stabilizers, for example Phosphorus compounds, such as phosphoric acid or phosphoric acid esters, are used. Typical antiblocking agents (also referred to as pigments in this context)  are inorganic and / or organic particles, for example calcium carbonate, amorphous silica, talc, magnesium carbonate, barium carbonate, calcium sulfate, Barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, Aluminum oxide, lithium fluoride, calcium, barium, zinc or manganese salts of the set dicarboxylic acids, carbon black, titanium dioxide, kaolin or cross-linked polystyrene or Acrylate particles.

Mixtures of two or more different ones can also be used as additives Antiblocking agents or mixtures of antiblocking agents of the same composition, however, different particle sizes can be selected. The particles can individual layers in the usual concentrations, e.g. B. as a glycolic dispersion added during polycondensation or via masterbatches during extrusion become. Pigment concentrations of 0.0001 to have been found to be particularly suitable 10 wt .-% proven, based on the weight of the layers equipped with it. By adding these particles z. B. in the top layer A according to the invention another advantageous way to vary the degree of matting of the film. With the An increase in pigment concentration is usually an increase in Matt degrees of the film connected. A detailed description of the antiblocking agents can be found, for example, in EP-A 0 602 964.

The present invention also relates to a method for producing the film according to the invention. It includes that

• a) Production of a film from base and top layers and any existing Intermediate layers by coextrusion,
• b) biaxial stretching of the film and
• c) heat setting of the stretched film.

To produce the matt top layer according to the invention are useful Granules from mixture component I and granules from Mixing component II in the desired mixing ratio directly to the extruder fed. It has proven useful for the extrusion of the  to use a matte top layer according to the invention a twin-screw extruder, how he z. B. is described in EP-A 0 826 478. The two materials can be melt at about 300 ° C and with a residence time of about 5 min and extrude. Under these conditions, transesterification reactions can take place in the extruder expire in which further copolymers of the homopolymers and Can form copolymers.

The polymers for the base layer are fed via a further extruder. Approximately Existing foreign bodies or impurities can be removed from the polymer melt Filter off before extrusion. The melts are then in a multi-layer die formed into flat melt films and layered on top of each other. Subsequently the multilayer film with the help of a cooling roller and optionally other rollers peeled and solidified.

The flame retardant is preferably added via masterbatch technology. The flame retardant is dispersed in a carrier material. As a carrier material come the bibenzol-modified thermoplastic itself or other polymers that with which thermoplastics are compatible, in question.

The colorant is also preferably metered in via masterbatch technology but can also be incorporated directly at the raw material manufacturer.

The light stabilizer, which may be added, can already be added to the thermoplastic Raw material manufacturers are metered in or in the film production in the extruder be dosed. The addition of the light stabilizer via is particularly preferred Masterbatch technology. The light stabilizer is in a solid carrier material dispersed. The bibenzene-modified thermoplastic comes as the backing material or other polymers that are sufficiently compatible with the thermoplastic, in question.  

The advantage of masterbatch technology is if the grain size and that Bulk weight of the masterbatch similar to the grain size and bulk density of the Thermoplastics are, so that a homogeneous distribution and thus z. B. a homogeneous Flame resistance is guaranteed.

It is also advantageous if the masterbatch containing the flame retardant and optionally contains the hydrolysis stabilizer, pre-crystallized or pre-dried becomes. This predrying involves gradual heating of the masterbatch reduced pressure (20 to 80 mbar, preferably 30 to 60 mbar, in particular 40 to 50 mbar) and with stirring and, if necessary, drying at constant, elevated temperature also under reduced pressure. The masterbatch will preferably at room temperature from a dosing container in the desired one Mixing together with the polymers of the base and / or cover layers and / or intermediate layers and possibly further raw material components in batches a vacuum dryer that turns on during the drying or dwell time Temperature range from approx. 10 ° C to 160 ° C, preferably 20 ° C to 150 ° C, passes through in particular 30 ° C to 130 ° C, filled. During the approximately 6-hour the residence time is preferably 5 hours, in particular 4 hours Raw material mixture with 10 to 70 rpm, preferably 15 to 65 rpm, in particular 20 stirred up to 60 rpm. The raw material mixture thus pre-crystallized or pre-dried in a downstream likewise evacuated container at 90 ° to 180 ° C, preferably 100 ° C to 170 ° C, in particular 110 ° C to 160 ° C for 2 to 8 hours, preferably post-dried for 3 to 7 hours, in particular 4 to 6 hours.

The film according to the invention is multi-layered. The film is made of at least one Base layer and at least one matt cover layer A, but has preferably also a second cover layer C. Structure, thickness and The composition of this second cover layer can be independent of that already existing top layer can be selected, the second top layer also the already mentioned polymers or polymer mixtures for the base or may contain the first cover layer according to the invention, but which is not with those of  first cover layer must be identical. The second top layer can also be different common top layer polymers contain.

If necessary, there may still be between the base layer and the cover layers one or more intermediate layers. You can e.g. B. from for Polymers described base layers exist. In a particularly preferred Embodiment they consist of the polymer used for the base layer. They can also contain the usual additives described. The thickness of the Interlayer is generally larger than 0.3 microns and is preferably in Range from 0.5 to 15 µm, especially 1.0 to 10 µm.

The thickness of the cover layers is generally greater than 0.1 μm and lies preferably in the range from 0.2 to 5 μm, in particular 0.2 to 4 μm, the Cover layers can be of the same or different thickness.

The total thickness of the film according to the invention can vary within wide limits and depends on the intended use. It is preferably 4 to 500 µm, in particular 5 to 450 µm, preferably 6 to 300 µm, wherein the base layer is preferably about 40 to 90% of the Total thickness.

In a special embodiment, a cover layer can also consist of a unmodified polyalkylene terephthalate homopolymers, from a isophthalic acid-modified polyalkylene terephthalate, from a bibenzene-modified and / or unmodified polyalkylene naphthalate polymers or from a bibenzene-modified and / or unmodified polyalkylene therapy- Polyalkylene naphthalate copolymers or compound exist. Here too are PET and PEN preferred polymers.

In this embodiment, the thermoplastics of the cover layers preferably have one Standard viscosity similar to the bibenzol-modified thermoplastic of the base layer.  

The films according to the invention can be prepared by known methods by coextrusion from a bibenzol-modified thermoplastic with possibly further masterbatches and / or raw materials / polymers and / or other conventional additives in the usual way Quantity of about 0.1 to a maximum of 10 wt .-% produced as multilayer films be, the multilayer, coextruded films with the same or differently designed surfaces can be produced, one For example, the surface is pigmented and the other surface is not a pigment contains. Likewise, one or both surfaces of the film can be made according to known ones Process can be provided with the functional coatings described.

Biaxial stretching is generally carried out sequentially or simultaneously. With sequential stretching, it is preferably only in the longitudinal direction (i.e. in Machine direction) and then in the transverse direction (i.e. perpendicular to Machine direction). This leads to an orientation of the molecular chains. The Stretching in the longitudinal direction can be done with the help of two according to the desired one Carry out stretching ratio of rolls running at different speeds. To the cross stretching generally uses a corresponding tenter frame. In the The film is simultaneously stretched simultaneously in the longitudinal and transverse directions in one Tenter frame stretched.

The temperature at which the drawing is carried out can be in a relative vary widely and depends on the desired properties of the Foil. In general, the longitudinal stretching at about 80 to 135 ° C and the Cross stretching is carried out at approx. 90 to 150 ° C. The longitudinal stretch ratio is generally in the range from 2.5: 1 to 6: 1, preferably from 3: 1 to 5.5: 1 Cross-stretch ratio is generally in the range from 3.0: 1 to 5.0: 1, preferably from 3.5: 1 up to 4.5: 1. If desired, another can be added to the transverse stretch Connect longitudinal stretching and even a further transverse stretching.  

In the subsequent heat setting, the film is held at about 0.1 to 10 s Temperature kept from about 150 to 250 ° C. Then the film is in the usual Way wrapped up.

Weathering tests have shown that the matt films according to the invention themselves after 5 to 7 years (extrapolated from weathering tests) outdoor use in generally no increased yellowing, no embrittlement, no cracking on the Surface and have no deterioration in mechanical properties.

Another advantage is that the manufacturing cost of the invention Film is only slightly above that of a film made of standard polyester raw materials. The other processing and use properties of the The film according to the invention remains or remains essentially unchanged even improved. In addition, the manufacture of the film ensures that this Regenerate in a proportion of up to 50% by weight, preferably 10 to 50% by weight, in each case based on the total weight of the film, can be reused without the physical properties of the film are negatively affected become.

The film is therefore ideal for packaging light and / or air sensitive food and beverages.

Because of the good UV stability and flame stability, the invention is suitable Film also for outdoor applications, such as. B. for greenhouses, canopies, Exterior cladding, covers, applications in the construction sector and in the Electrical industry, for applications in the refrigerator and freezer sector and for Illuminated advertising profiles.

In summary, the film according to the invention is characterized by a UV light Impermeability, high inherent UV stability, low gloss, in particular a low gloss of the film surface A, and by  comparatively low turbidity. It also has a good winding and Processing performance. The film can also be flame-retardant and / or colored transparent and / or provided with a sealing layer and / or line coated and / or corona treated. The high inherent UV stability can be further improved by the additive addition of a UV stabilizer. Farther it is worth mentioning that the top layer A according to the invention works well with ballpoint pens, Felt-tip pen or fountain pen can be labeled.

The gloss of the film surface A is preferably less than 70. In a preferred one Embodiment, the gloss of this side is less than 60 and in one particular preferred embodiment less than 50. This film surface thus has a particularly high advertising character and is therefore particularly suitable as outer surface of a packaging.

The haze of the film is preferably less than 40%. In a preferred one In one embodiment, the haze of the film is less than 35% and in one particularly preferred embodiment less than 30%. By comparative low cloudiness of the film, the film can e.g. B. can be printed in reverse printing or it Viewing windows can be installed through which z. B. to recognize the contents very well is.

Due to the surprising combination of excellent properties, the film according to the invention excellent for a large number of different applications, for example for interior cladding, for exhibition stand construction and exhibition items, as Displays, for signs, for protective glazing of machines and vehicles, in Lighting sector, in shop and shelf construction, for promotional items, as a lamination medium, for greenhouses, roofing, external cladding, covers, Applications in the construction sector and illuminated advertising profiles, shadow mats, Electrical applications and for a variety of other molded articles.  

Further areas of application are the use for the production of labels (Labels), as a release film for the production of GRP semi-finished products, as an embossing film or in- Mold-Labeling.

The table below (Table 1) summarizes the most important of the invention Film properties together again.  

Table 1

The following methods were used to characterize the raw materials and the foils:
measurement methods:
DIN = German Institute for Standardization
ISO = International Organization for Standardization
ASTM = American Society for Testing and Materials.

surface gloss

The surface gloss is measured at a measuring angle of 60 ° according to DIN 67530.  

Light transmission (turbidity)

Below the light transmission is the ratio of the total transmitted light to understand the amount of incident light.

The light transmission is carried out with the "Hazegard plus" measuring device in accordance with ASTM D 1003 measured.

surface defects

The surface defects are determined visually.

Mechanical properties

The modulus of elasticity, the tensile strength and the elongation at break are in longitudinal and Transverse direction measured according to ISO 527-1-2.

SV (DCE), IV (DCE)

The standard viscosity SV (DCE) is based on DIN 53726 in dichloroacetic acid measured.

The intrinsic viscosity (IV) is calculated from the standard viscosity (SV) as follows:
IV (DCE) = 6.67.10 ^-4 .SV (DCE) + 0.118

Weathering (both sides), UV stability

The UV stability is tested according to the test specification ISO 4892 as follows:
Test device: Atlas Ci 65 Weather Ometer
Test conditions: ISO 4892, ie artificial weathering
Irradiation time: 1000 hours (per side)
Irradiation: 0.5 W / m ² , 340 nm
Temperature: 63 ° C
Relative humidity: 50%
Xenon lamp: inner and outer filter made of borosilicate
Irradiation cycles: 102 minutes of UV light, then 18 minutes of UV light with water spraying the samples, then again 102 minutes of UV light, etc.

Yellowness Index (YID)

The yellowness index YID is the deviation from the colorlessness in the direction of "yellow" and will measured according to DIN 6167.

fire behavior

The fire behavior is according to DIN 4102 part 2, building material class B2 and DIN 4102 Part 1, building material class B1 and determined 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 (Sealing seam 20 mm × 100 mm) made, the film 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 is sealed. From the sealed samples were Cut test strips 15 mm wide. The T-seal strength was the same as for the Determination of the seal seam strength measured. The seal starting temperature is that Temperature at which a seal seam strength of at least 0.5 N / 15 mm is reached becomes.

Seal strength

Two 15 mm wide film strips were used to determine the seal seam strength one on top of the other and 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) sealed. The Seal seam strength was determined by the T-Peel method.

All foils were processed on both sides per 1000 hours per the test specification ISO 4892 Weathered side with the Atlas Ci 65 Weather Ometer from Atlas and then  in terms of mechanical properties, discoloration, surface defects, of turbidity and gloss checked.

The invention is explained in more detail below on the basis of exemplary embodiments.

Examples example 1 A) Preparation of component II for the top layer mixture according to the invention

A copolyester with 90 mol% of isophthalic acid and 10 mol% of the sodium salt of 5-sulfoisophthalic acid as the acid component and 100 mol% of ethylene glycol as the glycol component was prepared by the following procedure:
A 2 liter stainless steel reaction vessel equipped with an anchor stirrer, a thermocouple to measure the temperature of the vessel contents, an 18 inch Claisen / Vigreux distillation column with a cooler and receiver, an inlet opening and a heating jacket was preheated to 190 ° C , flushed with nitrogen and filled with 1065.6 g of dimethyl isophthalate, 180.6 g of dimethyl 5-sulfoisophthalate sodium salt and 756.9 g of ethylene glycol. A buffer (Na ₂ CO ₃ .10 H ₂ O - 0.439 g) and a transesterification catalyst (Mn (OAc) ₂ .4 H ₂ O - 0.563 g) were also added to the vessel. The mixture was heated with stirring while methanol was distilled off. During the distillation, the vessel temperature was gradually raised to 250 ° C. When the weight of the distillate corresponded to the theoretical methanol yield, an ethylene glycol solution containing 0.188 g of phosphorous acid was added. The distillation column was replaced with a curved steam outlet with template. 20 g of pure ethylene carbonate were added to the reaction mixture, and violent gas evolution (CO ₂ ) started immediately. The CO ₂ development subsided after about 10 minutes. A vacuum of 240 mm Hg was then drawn and the polycondensation catalyst (0.563 g Sb ₂ O ₃ ) added in an ethylene glycol slurry. The reaction mixture was stirred for 10 minutes while maintaining the negative pressure of 240 mm Hg, after which the pressure was further reduced in steps of 10 mm Hg / min from 240 mm Hg to 20 mm Hg. As soon as the vacuum in the system was reduced to 20 mm Hg, the vessel temperature was raised from 250 ° C to 290 ° C at a rate of 2 ° C / min. At a temperature of 290 ° C in the vessel, the stirrer speed was reduced and the pressure was reduced to a maximum of 0.1 mm Hg. At this point an ammeter reading of the stirrer motor was carried out. The viscosity of the polymer was controlled by letting the polycondensation proceed according to fixed values for the change in the amperage of the stirrer motor of (in each case) 2.3 A. When the desired molecular weight was reached, the vessel was pressurized with nitrogen to force the liquid polymer from the bottom plug of the vessel into a quench bath of ice water.

B) Mixture preparation for the cover layer A according to the invention

85% by weight of component I (polyethylene terephthalate with an SV value of 680) with 15% by weight of component II Twin-screw extruder fed and both components together at about 300 ° C. extruded and fed to the top layer channel A of a multi-layer nozzle.

Through coextrusion and subsequent stepwise orientation in longitudinal and The transverse direction then became a matt three-layer film with ABC structure and one Total thickness of 12 microns. The cover layers had a thickness of each 1.5 µm.

Base layer B:
95% by weight bibenzene modified polyethylene terephthalate (PETBB). The PETBB has a standard viscosity SV (DCE) of 810, which corresponds to an intrinsic viscosity IV (DCE) of 0.658 dl / g. The bisbenzene acid content is 15% by weight, the glass transition temperature is 86 ° C.
5% by weight of masterbatch made of 99% by weight of PETBB and 1.0% by weight of silica particles (Sylobloc® 44 H from Grace, Germany) with an average particle size of 4.5 μm.

Top layer A:
85% by weight of component I and
15% by weight of component II

Top layer C:
90% by weight PETBB and
10% by weight of masterbatch made from 99% by weight of PETBB and 1.0% by weight of silica particles (Sylobloc® 44 H from Grace) with an average particle size of 4.5 μm.

The individual process steps were:
longitudinal stretching
Temperature: 85-135 ° C
Longitudinal aspect ratio: 4.0: 1
transverse stretching
Temperature: 85-135 ° C
Lateral stretch ratio: 4.0: 1
fixation
Temperature: 230 ° C

After the longitudinal stretching, the film is coated on both sides with an aqueous dispersion by means of the “reverse gravure-roll coating” method. In addition to water, the dispersion contains 4.2% by weight of hydrophilic polyester (5-Na-sulfoisophthalic acid-containing PET / IPA polyester, SP41®, from Ticona, USA), 0.15% by weight of colloidal silicon dioxide (Nalco 1060®, Deutsche Nalco Chemie, Germany) as an antiblocking agent and 0.15% by weight ammonium carbonate (Merck, Germany) as a pH buffer. The wet application weight is 2 g / m ² per coated side. After the transverse stretching, the calculated thickness of the coating is 40 nm.

Example 2

Analogously to Example 1, a 50 μm thick A-B-C film is produced. In contrast to Example 1 contains an additional 0.6% by weight to improve the UV stability of the UV stabilizer 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) oxyphenol (®Tinuvin  1577 from Ciba-Geigy) in the base layer B and the top layer C. The UV Stabilizer is in the form of a masterbatch (20% by weight Tinuvin, 80% by weight PETBB) added.

Tinuvin® 1577 has a melting point of 149 ° C and is thermal up to approx. 330 ° C stable.

Example 3

A 19 µm thick co-extruded A-B-C film is produced.

The main component of the 16 μm thick base layer B is PETBB, 0.2% by weight Hydrolysis stabilizer and 4% by weight flame retardant. The layer still contains 30% by weight of the self-generated regenerative material inherent in film production.

The outer layers A and C are identical to the outer layers from example 1.

The PETBB from which the transparent film is made has one Standard viscosity SV (DCE) of 810, indicating an intrinsic viscosity IV (DCE) of 0.658 dl / g.

The hydrolysis stabilizer and the flame retardant are in the form of a Masterbatches added. The masterbatch consists of 20% by weight Flame retardant, 1 wt .-% hydrolysis stabilizer and 79 wt .-% PETBB together.

The hydrolysis stabilizer is pentaerythrityl tetrakis-3- (3,5-di- Tertiarybutyl-4-hydroxyphenyl) propionate. The flame retardant is the organic phosphorus compound dimethyl methylphosphonate.

Example 4

Analogously to example 3, a 19 μm thick ABC film is produced. In contrast to Example 3, after longitudinal stretching, the film is coated on one side on the top layer C using an “reverse gravure-roll coating” method with an aqueous dispersion. In addition to water, the dispersion contains 4.2% by weight of hydrophilic polyester (5-Na-sulfoisophthalic acid-containing PET / IPA polyester, SP41®, Ticona, USA), 0.15% by weight of colloidal silicon dioxide (Nalco 1060®, Deutsche Nalco Chemie, Germany) as an antiblocking agent and 0.15% by weight ammonium carbonate (Merck, Germany) as a pH buffer. The wet application weight is 2 g / m ² per coated side. After the transverse stretching, the calculated thickness of the coating is 40 nm.

Example 5

A 12 µm thick, coextruded, sealable A-B-C film is produced.

The 10 μm thick base layer B contains PETBB as the main component and 30% by weight. of the inherent regenerate that is inherent in film production.

For the 1 µm thick sealable cover layer C, a copolyester is used as the thermoplastic from 78 mol% ethylene terephthalate and 22 mol% ethylene isophthalate (produced via the transesterification process with Mn as transesterification catalyst, Mn- Concentration: 100 ppm).

It also contains 3.0% by weight of a masterbatch of 97.75% by weight of copolyester and 1.0% by weight of ®Sylobloc 44 H (synthetic SiO ₂ from Grace) and 1.25% by weight ®Aerosil TT 600 (pyrogenic SiO ₂ from Degussa, Germany).

Cover layer A is identical to cover layer A from example 1.

The PETBB from which the transparent film is made has one Standard viscosity SV (DCE) of 810, indicating an intrinsic viscosity IV (DCE) of 0.658 dl / g.  

Example 6

Analogously to example 5, a 12 μm thick, transparent, coextruded, sealable ABC film is produced. In contrast to Example 5, the non-sealable top layer A is coated with an aqueous dispersion after the longitudinal stretching by means of the “reverse gravure-roll coating” method. In addition to water, the dispersion contains 4.2% by weight of hydrophilic polyester (5-Na-sulfoisophthalic acid-containing PET / IPA polyester, SP41®, Ticona, USA), 0.15% by weight of colloidal silicon dioxide (Nalco 1060®, Deutsche Nalco Chemistry, Germany) as an antiblocking agent and 0.15% by weight ammonium carbonate (Merck, Germany) as a pH buffer. The wet application weight is 2 g / m ² per coated side. After the transverse stretching, the calculated thickness of the coating is 40 nm.

Example 7

Analogously to Example 6, a 12 µm thick, transparent, coextruded, sealable A-B C-film produced, which is also on the top layer C with the SP41 adhesion promoter is coated.

In contrast to the film from Example 6, the base layer B contains 1.5% by weight Solvent Blue 35 (fat-soluble anthraquinone dye, ®Sudan Blue 2, BASF, Germany). The colorant is added in the form of a masterbatch, which is next to PETBB contains 20 wt .-% blue colorant.

Example 8

Analogously to Example 7, a 12 µm thick, transparent, coextruded, colored, sealable A-B-C film produced. In contrast to example 7, the film is uncoated.

The film is corona-treated on the top layer C. The intensity is chosen so that the surface tension is <45 mN / m.

Example 9

Analogously to Example 2, a 50 μm thick A-B-C film is produced.  

Analogous to Example 2, the film already contains inherently to further improve existing UV stability an additional 0.6% by weight of the UV stabilizer 2- (4,6-diphenyl- 1,3,5-triazin-2-yl) -5- (hexyl) oxyphenol (®Tinuvin 1577 from Ciba-Geigy). The UV Stabilizer is in all layers ABC in the form of a 20 wt .-% masterbatch added.

The film also contains 0.2% by weight of hydrolysis stabilizer and 4% by weight. Flame retardants. The hydrolysis stabilizer and the flame retardant are in Formed into a master batch in all layers ABC. The masterbatch settles from 20% by weight flame retardant, 1% by weight hydrolysis stabilizer and 79% by weight PETBB together. The hydrolysis stabilizer is pentaerylthrityl Tetrakis-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate. With the flame retardant it is the organic phosphorus compound dimethyl methylphosphonate.

The films also contain 1.5% by weight of solvent blue 35 (fat-soluble anthraquinone Dye, ®Sudan Blue 2, BASF, Germany). The colorant is in the form of a Masterbatches metered into all layers of ABC, the 20% by weight blue in addition to PETBB Contains colorants.

After the longitudinal stretching, the film is coated on both sides with an aqueous dispersion by means of the “reverse gravure-roll coating” method. In addition to water, the dispersion contains 4.2% by weight of hydrophilic polyester (5-Na-sulfoisophthalic acid-containing PET / IPA polyester, SP41®, Ticona, USA), 0.15% by weight of colloidal silicon dioxide (Nalco 1060®, Deutsche Nalco Chemistry, Germany) as an antiblocking agent and 0.15% by weight ammonium carbonate (Merck, Germany) as a pH buffer. The wet application weight is 2 g / m ² per coated side. After the transverse stretching, the calculated thickness of the coating is 40 nm.

Comparative Example 1 (VB1)

Analogously to example 1, a 12 μm thick A-B-C film is produced. Instead of PETBB becomes an unmodified PET homopolymer with the same thermoplastic Viscosity used.

The properties of the films produced are shown in Table 2 below remove.  

Show after every 1000 hours of weathering per side with Atlas Ci 65 Weather Ometer hardly changed the bibenzol-modified PET films from Examples 1 to 9 Characteristics.

After 1000 hours of weathering per side with Atlas Ci 65 Weather Ometer, the Film from comparative example 1 on the surfaces of cracks and Signs of embrittlement. A precise property profile - especially regarding the mechanical properties - can therefore no longer be measured. This film also shows a visually visible yellow color.

Claims (36)

1. Multi-layer film, characterized in that it has a base layer, which contains a crystallizable, bibenzol-modified thermoplastic as the main component, and at least one matt cover layer, which contains a mixture or a blend of two components I and II, and at least one additional functionality. 2. Film according to claim 1, characterized in that the amount of Bibenzol-modified thermoplastics, based on the weight of the finished layers, 50 to 99.9% by weight, preferably 75 to 99% by weight, is. 3. Film according to claim 1 or 2, characterized in that it consists of a Base layer B and two cover layers A and C with the layer sequence A-B-C is constructed, the cover layers can be the same or different. 4. Film according to one or more of claims 1 to 3, characterized characterized in that they have additional intermediate layers, preferably 2nd additional intermediate layers. 5. Film according to one or more of claims 1 to 4, characterized characterized that as a thermoplastic a bibenzol-modified polyester is used. 6. Film according to one or more of claims 1 to 5, characterized characterized as bibenzol-modified polyester Polyethylene terephthalate, bibenzene-modified polybutylene terephthalate or Bibenzol-modified polyethylene naphthalate is used.   7. Film according to one or more of claims 1 to 6, characterized characterized that as a bibenzol-modified thermoplastic Bibenzol-modified polyethylene terephthalate is used. 8. Film according to one or more of claims 1 to 7, characterized characterized that the standard viscosity SV (DCE) of the bibenzene-modified polyethylene terephthalate between 600 and 1000, preferably between 700 and 900. 9. Film according to one or more of claims 1 to 8, characterized characterized in that the bibenzenic acid content, based on the weight of the bibenzene-modified thermoplastics, 1 to 50% by weight, preferably 5 to 45% by weight, in particular 10 to 40% by weight. 10. Film according to one or more of claims 1 to 9, characterized characterized that a top layer and any existing Intermediate layers a bibenzol-modified thermoplastic, preferred that of the base layer. 11. Film according to one or more of claims 1 to 10, characterized characterized that a top layer and any existing Intermediate layers of unmodified polyalkylene terephthalate, bibenzene-modified and / or unmodified polyalkylene naphthalate or bibenzene-modified and / or unmodified polyalkylene terephthalate Contain polyalkylene naphthalate copolymer. 12. Film according to one or more of claims 1 to 11, characterized characterized in that as component I a thermoplastic polyester, preferably polyethylene terephthalate homopolymer, polyethylene terephthalate Copolymer or a mixture of polyethylene terephthalate homo- and / or Copolymers.   13. Film according to one or more of claims 1 to 12, characterized characterized in that a polymer is used as component II, the one Has sulfonate group. 14. Film according to one or more of claims 1 to 13, characterized in that the condensation product of the following monomers or their derivatives capable of forming polyesters is used as component II:

• a) 65 to 95 mol% of isophthalic acid,
• b) 0 to 30 mol% of at least one aliphatic dicarboxylic acid of the formula HOOC (CH ₂ ) _n COOH, where n is a number from 1 to 11,
• c) 5 to 15 mol% of at least one sulfomonomer which has an alkali metal sulfonate group on the aromatic part of an aromatic dicarboxylic acid, and
• d) the amount of a copolymerizable aliphatic or cycloaliphatic glycol having 2 to 11 carbon atoms necessary to form 100 mol% of condensation product.

15. Film according to one or more of claims 1 to 14, characterized characterized in that as component II b) malon, adipine, azelaine, glutaric, Sebacic, cork, amber or brassylic acid or their for the formation of Polyester-enabled derivatives or mixtures of these substances are used become. 16. Film according to one or more of claims 1 to 15, characterized in that as component II c) monomers of the formula
are used, where M is alkali metal, preferably Na, Li or K, Z is a trivalent aromatic radical and X and Y are carboxyl groups or polyester-forming equivalents. 17. Film according to one or more of claims 1 to 16, characterized characterized in that as component II d) ethylene glycol, 1,5-pentanediol, 1,6- Hexanediol, neopentylglycol, 1,10-decanediol or cyclohexane-dimethanol, preferably ethylene glycol is used. 18. Film according to one or more of claims 1 to 17, characterized characterized in that the weight ratio of component I: component II 10: 90 to 95: 5. 19. Film according to one or more of claims 1 to 18, characterized characterized that the standard viscosity SV (DCE) of component I 500 to 800, preferably 500 to 700. 20. Film according to one or more of claims 1 to 19, characterized characterized that the standard viscosity SV (DCE) of component II 300 to 700, preferably 350 to 650. 21. Film according to one or more of claims 1 to 20, characterized characterized in that the film has at least one flame retardant and / or contains at least one UV stabilizer and / or is sealable and / or on one or both surfaces is coated and / or corona treated. 22. Film according to one or more of claims 1 to 21, characterized characterized in that the film as a UV stabilizer or 2-hydroxybenzotriazoles Contains triazines or mixtures of various UV stabilizers. 23. Film according to one or more of claims 1 to 22, characterized characterized in that the film contains the UV stabilizer in a concentration of 0.01 to 5 wt .-%, based on the weight of the so equipped Layers.   24. Film according to one or more of claims 1 to 23, characterized characterized that the film as a flame retardant organic Phosphorus compounds, preferably carboxyphosphinic acids or their Anhydrides, especially dimethyl methylphosphonate, or mixtures contains various flame retardants. 25. Film according to one or more of claims 1 to 24, characterized characterized in that the film contains the flame retardant in a concentration from 0.5 to 30% by weight, preferably from 1 to 20% by weight, based on the Weight of the layers equipped with it. 26. Film according to one or more of claims 1 to 25, characterized characterized in that the film is a hydrolysis stabilizer, preferably in a Concentration of 0.01 to 1 wt .-%, based on the weight of it equipped layers. 27. Film according to one or more of claims 1 to 26, characterized characterized in that the sealable film has a seal starting temperature of less than 110 ° C and a seal seam strength of at least 1.3 N / 15 mm having. 28. Film according to one or more of claims 1 to 27, characterized characterized that the film is colored transparent. 29. Film according to one or more of claims 1 to 28, characterized characterized in that the film is functional on one or both surfaces is coated. 30. Film according to one or more of claims 1 to 29, characterized characterized in that the matt film surface has a gloss of less than 70, preferably less than 50.   31. Film according to one or more of claims 1 to 30, characterized characterized in that it has a haze of less than 40%, preferably less than 30%. 32. Film according to one or more of claims 1 to 31, characterized characterized in that the film usual additives such as antiblocking agents, Contains stabilizers or lubricants. 33. Inherently UV-stabilized film, characterized in that it is a film according to one or more of claims 1 to 32. 34. A method for producing a film according to one or more of the claims 1 to 33, characterized in that one for the production of the film required raw materials co-extruded through a slot die, the obtained Biaxially stretched and heat-set film and, if necessary, on one or both sides coated. 35. Use of a film according to one or more of claims 1 to 33 for Manufacture of moldings. 36. Moldings produced using a film according to one or more of claims 1 to 33.