DE102005025233A1 - White opaque foil for electrical isolating, protection glazings and signboard, comprises crystallizable thermoplastic polyester having soluble dye, barium sulfate, titanium dioxide and brightener - Google Patents

Abstract

The foil has 50 wt% of crystallizable thermoplastic polyester, 1-20 wt% of barium sulfate and titanium dioxide and 1-25000 ppm of optical brighteners related to the weight of the thermoplastics of a pigmented layer. The polyester units are ethyleneglycol and terephthal acid and/or isophthal acid, naphthalin-1,5-dicarbonicacid or naphthalin-2,6-dicarbonicacid. The polyester (greater than 50 wt%) is polyethylene terephthalate, polyethylene naphthalate or their mixtures. The foil further comprises a base layer, sealable surface layers. The surface layer contains polyethylene terephthalate, polyethylene naphthalate or a copolymer of polyethylene terephthalate-polyethylene naphthalate. The foil exhibits 1-20% of transparency and yellow value with a thickness of 50 mu m, white degree of greater than 85%, dielectric strength of larger than 150 kv/mm, void-index of larger than 87% and density of larger than 1.39 kg/dm3>. The foil: is corona treated for the additional functionality; exhibits an additional functionality and shrinks of smaller than 2.5% in longitudinal and transverse direction when it is heated at 150[deg]C for 15 minutes; has adhesive coating with aminosilane or silicone; and is equipped with hydrolysis stabilizers, ultraviolet stabilizers and flame retardant for obtaining the additional functionality. An independent claim is included for production a white opaque foil.

Description

The The invention relates to a white-opaque Film with low transparency and improved dielectric strength from a crystallizable thermoplastic, which is an additional functionality having. The foil contains at least barium sulfate and titanium dioxide as pigments and at least an optical brightener and optionally one or more soluble in thermoplastics Dyes and has at least one additional functionality. The Film is characterized by good stretchability, by a low transparency, improved dielectric strength as well very good optical properties. The invention further relates a method of making this film and its use.

opaque Films with a thickness between 10 and 500 microns are known.

In EP-A-1 125 967 are likewise white-opaque films of crystallisable Thermoplastics described. However, there is no such thing in this document Statement about the dielectric strength or density of the films produced made. About that In addition, these films contain only barium sulfate and an optical Brighteners. The transparency of these films is in all the examples listed at> 12% and is therefore not for the applications required here suitable.

US 4,780,402 describes white films with barium sulfate, optionally optical brightener and optionally incompatible polymer to adjust the transparency. The density of all these films is in the range of 1.1 to 1.33 kg / dm ³ . This low density indicates a very large number of voids (vacuoles), which leads to a significantly reduced dielectric strength. In addition, the yellowness index of these films is in the negative range, ie the film is bluish.

task The present invention was to provide a white-opaque film having a thickness of preferably 10 to 500 microns to provide, in addition to a good drawability, good optical Properties, a low yellowness index especially a high whiteness, a additional functionality as well as a low transparency and a good electrical breakdown strength having.

A additional functionality means that the film according to the invention Flame retardant and / or with additional Equipped with UV stabilizers is and / or sealable is and / or coated on one or both surfaces and / or Corona treated on one or both sides and / or with hydrolysis stabilizers equipped and / or shrunk.

To the good optical properties include, for example, a homogeneous, streak-free coloring, a low light transmission / transparency (thickness dependent, at 50 μm film: preferably 1 to 20%, in particular 2 to 17%, particularly preferably 3 to 15%; for 200 μm film: preferably 0.5 to 8%, in particular 0.6 to 7%, particularly preferably 0.7 to 6%), as well as a low yellowness index YID (depending on thickness, at 50 μm film: preferably 1 to 15, in particular 2 to 14, particularly preferred 3 to 13; for 200 μm film: preferably 1 to 50, in particular 2 to 45, particularly preferably 3 to 40).

One high whiteness means the whiteness the films according to Berger according to the invention preferred at> 85 %, preferably> 87 %, especially at> 90 % lies.

To Good drawability counts, that the film in its production both in longitudinal and can also be oriented well in the transverse direction and without breaks.

A high dielectric strength means that the dielectric strength a 50 μm thick Foil measured according to DIN 53481 according to the ball / plate method Alternating voltage (AC) preferably> 150 kV / mm, preferably> 160 kV / mm, more preferably> 170 kV / mm. The dielectric strength is thickness-dependent. The thicker the film, the lower the dielectric strength.

The density of the film according to the invention is preferably greater than 1.390 kg / dm ³ , in particular greater than 1.392 kg / dm ³ , particularly preferably greater than 1.394 kg / dm ³ .

The density of the film is largely determined by the number and size of the vacuoles. The more Vacuoles and the larger the vacuoles, the lower the density. For example, the calculated density of a film containing 18% by weight of barium sulfate or titanium dioxide is 1.60 kg / dm ³ . As a measure of the formation of vacuoles (Voids) applies the so-called void index. The void index is defined as the quotient of measured density and calculated density.

Of the Void index of the films of the invention is preferably> 87 %, especially at> 88 %, more preferably> 89 %. If the void index is 100%, then measured density and calculated density equal, i. there is a vacuole.

Furthermore should the film of the invention be recyclable, in particular without deterioration of the dielectric strength and loss of optical and mechanical properties, with it They also for example Electrical insulation applications, indoor applications and used in exhibition construction can be.

Is solved this task by a white-opaque Film having a thickness in the range of preferably 10 to 500 microns, as Main component contains a crystallizable thermoplastic (main component means> 50% by weight based on the total weight of the film). The film also contains at least barium sulfate and titanium dioxide as pigments, at least an optical brightener, optionally at least one in the thermoplastic soluble Dye and has at least one additional functionality. The Barium sulfate and / or the titanium dioxide and / or the optical brightener and / or the dyes can can be incorporated directly with the raw material manufacturer, or they can as Masterbatches are added directly during film production. The desired low transparency in addition to that Longitudinal stretch ratio of Slide can be adjusted.

The Film according to the invention contains as main component a crystallizable thermoplastic polyester (crystallizable thermoplastics). The polyester of the invention contains preferably units of ethylene glycol and terephthalic acid and / or Units of isophthalic acid, Naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid and / or biphenyl (= Bibenzoic acid) and / or units of aliphatic or cycloaliphatic diols having from 2 to 8 carbon atoms, in particular from propylene glycol, methylpropylene glycol, Butylene glycol and / or cyclohexanedimethanol. It is accordingly the thermoplastic according to the invention Polyester is preferably polyethylene terephthalate, polytrimethylene terephthalate, Polybutylene terephthalate, poly (1,4-cyclohexanedimethylene terephthalate), Polyethylene naphthalene-2,6-dicarboxylate, polyethylene naphthalene-1,5-dicarboxylate, Polytrimethylene naphthalate, polyethylene naphthalate / bibenzoate or other combinations of the monomers mentioned as well as mixtures this polyester. Polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) and mixtures thereof are preferred. In a further preferred embodiment contains the polyester in addition at least 5% by weight of isophthalic acid.

For the purpose The invention also mixtures of crystallizable thermoplastic Polyesters referred to as (crystallizable) thermoplastic or polyester.

Under the term polyethylene terephthalate or polyethylene naphthalate homopolymers, compounds, copolymers, recyclates and other variations are understood.

The polyester according to the invention can e.g. from dimethyl terephthalate by known methods, e.g. to the transesterification process (DMT process), wherein as transesterification catalysts zinc, magnesium, calcium, manganese, Lithium or germanium salts are suitable. You can also by direct esterification produced (PTA method). Furthermore, polyesters according to the invention available as commercial products.

used Polycondensation catalysts in the context of the invention are included Antimony or titanium compounds or mixtures thereof in a concentration in the polyester from 1 to 350 ppm (based on the metal), preferably 2 to 250 ppm, and more preferably 5 to 200 ppm.

The Film according to the invention can be both single-layered and multi-layered.

The Contains foil at least barium sulfate and titanium dioxide as pigments, wherein the Total concentration of the pigments preferably between 0.1 and 40 Wt .-%, based on the weight of the crystallizable thermoplastic, lies. Preferably, titanium dioxide and also barium sulfate on the so-called masterbatch technology either separately or together directly at the Added film production.

The Contains foil at least one optical brightener, wherein the optical brightener preferably in amounts of from 1 to 25,000 ppm, more preferably from 2 to 15,000 ppm, more preferably from 3 to 10,000 ppm, based on the weight of the crystallizable thermoplastic used becomes. Preferably, the optical brightener on the so-called masterbatch technology dosed directly during film production.

The according to the invention optical Brighteners are capable of producing UV rays in the range of 360 to 380 nm to absorb and as a long-wave, to give off visible blue-violet light again.

Suitable optical brighteners are, for example, bis-benzoxazoles, coumarin derivatives (benzotriazole-coumarin, naphthotriazole-coumanin) or also bis (styryl) biphenyls. Particularly preferred are ^® Uvitex OB-One (Ciba Specialties, Basel, CH), ^® Hostalux KS (Clariant, Germany), and ^® Eastobrite OB-1 (Eastman). These and other suitable systems are also described in "Plastics Additives Handbook", 5th Edition, Carl Hanser Verlag, Germany, 2001.

Provided appropriate can beside the optical brightener also one or more in the inventive polyester soluble Dyes are added. The dyes are available in quantities of preferably 1 to 100 ppm, more preferably 1 to 30 ppm, especially preferably 1 to 20 ppm, based on the weight of the crystallizable Thermoplastics, used.

It was completely surprising that the use of the above-mentioned combination of barium sulfate, Titanium dioxide, optical brightener and optionally added Dyes in the films preferably in conjunction with an increased Längsstreckverhältnis the film production to the desired Result led.

Of Another one is very surprising that also the regenerate can be used again, without the yellow value and the dielectric strength of the film appreciably negative to influence.

In a preferred embodiment be felled Barium sulfate types used. Precipitated barium sulfate is obtained Barium salts and sulfates or sulfuric acid as a finely divided colorless Powder whose grain size is due the precipitation conditions is to control. felled Barium sulphates can after the usual Procedures described in Plastic Journal 8, No. 10, 30-36 and No. 11, 36-31 (1974).

The Amount of barium sulfate is preferably 0.1 to 40 wt .-%, preferably 0.5 to 25 wt .-%, especially preferably 1 to 20 wt .-% based on the weight of the thermoplastic.

The mean particle size is relatively small and is in the range of preferably 0.1 to 5 .mu.m, in particular in the range of 0.2 to 3 microns. The density of the barium sulfate used is preferably between 4 and 5 g / cm ³ .

In a particularly preferred embodiment, the inventive film comprises, as main constituent, a crystallizable polyethylene terephthalate and 0.1 to 40 wt .-% of precipitated barium sulfate, conveniently microns with a particle diameter of 0.2 to 1, wherein ^® Blanc fixe XR-HX or ^® Blanc fixe HXH from the company Sachtleben Chemie is particularly preferred.

The used titanium dioxide particles consist either of the anatase or the rutile modification or Mixtures thereof, with rutile being preferred. Rutile shows in comparison to Anatas a higher one Opacity. In a preferred embodiment, the titania particles are at least 95% by weight of rutile. You can search for a usual one Method, for. B: after the chloride or sulfate process become. Your amount is preferably 0.1 to 40 wt .-%, based on the weight of the thermoplastic. The mean particle size is relative small and is preferably in the range of 0.1 to 1.0 microns.

By Titanium dioxide of the type described arise within the polymer matrix hardly vacuoles during the film production.

The titanium dioxide particles may have a coating of inorganic oxides commonly used as a coating for TiO ₂ white pigment in papers or paints to improve light fastness.

TiO ₂ is known to be photoactive. When exposed to UV rays, free radicals form on the surface of the particles. These free radicals can migrate into the polymer matrix, resulting in degradation reactions and yellowing. To avoid this, the TiO ₂ particles can be oxidized. Particularly suitable oxides for the coating include the oxides of aluminum, silicon, zinc or magnesium or mixtures of two or more of these compounds. TiO ₂ particles with a coating of several of these compounds are described, for example, in EP-A-0 044 515 and EP-A-0 078 633. Furthermore, the coating may contain or consist of organic compounds with polar and non-polar groups.

The organic compounds need in the production of the film by extrusion of the polymer melt be sufficiently thermostable. For example, polar groups are -OH; -OR; --COOX; (X = R, H or Na, R = alkyl having 1 to 34 carbon atoms). Preferred organic compounds are alkanols and fatty acids with 8 to 30 carbon atoms in the alkyl group, especially fatty acids and primary n-alkanols with 12 to 24 carbon atoms, as well as polydiorganosiloxanes and / or polyorganohydrogensiloxanes such as. Polydimethylsiloxane and polymethylhydrogensiloxane.

The coating for the titanium dioxide particles preferably consists of 1 to 12 g, in particular 2 to 6 g of inorganic Oxides and / or 0.5 to 3 g, in particular 0.7 to 1.5 g of organic Compound based on 100 g of titanium dioxide particles. The coating usually becomes on the particles in aqueous Suspension applied. The inorganic oxides can be made water-soluble Compounds, e.g. Alkali, in particular sodium nitrate, sodium silicate (Water glass) or silica in the aqueous Suspension precipitated become.

By inorganic oxides such as Al ₂ O ₃ or SiO ₂ are also the hydroxides or their various dewatering stages such as oxide hydrate to understand, without knowing their exact composition and structure. After annealing and grinding in aqueous suspension, the oxide hydrates, for example of aluminum and / or silicon, are precipitated on the TiO ₂ pigment, and the pigments are then washed and dried. This precipitation can thus be done directly in a suspension, as obtained in the manufacturing process after the annealing and the subsequent wet grinding. The precipitation of the oxides and / or oxide hydrates of the respective metals is carried out from the water-soluble metal salts in the known pH range, for aluminum, for example, aluminum sulfate in aqueous solution (pH less than 4) is used and by addition of aqueous ammonia solution or sodium hydroxide in the pH range between 5 and 9, preferably between 7 and 8.5, the oxide hydrate like. Assuming a water glass or alkali aluminate solution, the pH of the TiO ₂ suspension submitted should be in the strongly alkaline range (pH greater than 8). The precipitation is then carried out by addition of a mineral acid such as sulfuric acid in the pH range 5 to 8. After the precipitation of the metal oxides, the suspension is stirred for about 15 minutes to about 2 hours, the precipitated layers undergo aging. The coated product is separated from the aqueous dispersion and after washing at elevated temperature, in particular at 70 to 100 ° C, dried.

In a preferred embodiment, the film according to the invention contains, in addition to the crystallizable thermoplastic, which is preferably polyethylene terephthalate, from 0.1 to 40% by weight of rutile-type titanium dioxide having a particle diameter of from 0.1 to 0.5 μm, which acts as a masterbatch the film preparation is metered, with titanium dioxide from Kerr McGee ^(® Tronox RFK2) or Sachtleben ^(® Hombitan classes of R or RC) is preferred.

Furthermore, the film according to the invention preferably contains from 1 to 25,000 ppm of an optical brightener which is soluble in the crystallisable thermoplastic, whereby ^® Uvitex OB-One (Ciba Specialties, Basel, CH), ^® Hostalux KS and ^® Eastobrite OB-1 (Eastman) are particularly preferred. ppm means parts by weight based on the weight of the crystallizable thermoplastic or polyester. It is also possible to use mixtures of different brighteners.

The inventive film contains optionally one or more polyester-soluble dyes. The amount of the dyes preferably 1 to 100 ppm, in particular 1 to 30 ppm, particularly preferably 1 to 20 ppm. Below ppm, parts by weight are by weight the polyester containing the dyes understood. It can too Mixtures of different dyes are used.

It is advantageous for the film according to the invention that the dye (s) in addition to their solubility in polyester have a high thermal stability and do not migrate out of the film or evaporate out of the film during the production process and thus lead to undesirable deposits in the production plants. Furthermore, the dyes used for the polyester films according to the invention should be approved for food contact and for medical applications or suitable for approval be.

Under soluble Dyes are substances that are molecular in the polymer solved are (DIN 55949, EN12887).

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

at the coloring Dye is a solution process. As a result this solution process For example, the dye is molecularly dissolved, for example, in the polyester. such Become colorations as transparent or translucent or translucent or opal.

From the different classes of soluble Dyes are particularly preferred for the fat and aromatic soluble dyes. These are, for example, azo, phthalocyanine, isoquinoline, Methine and anthraquinone dyes or perinones. They are suitable especially for coloring of PET, because of the high glass transition temperatures of PET the migration of the dye is limited. (Literature J. Koerner: soluble Dyes in the plastics industry in "VDI-Gesellschaft Kunststofftechnik:": Dyeing of Plastics, VDI-Verlag, Dusseldorf 1975).

Suitable are also mixtures of two or more of these soluble Dyes.

Especially suitable dyes are those which have a high molecular weight, because these dyes have a lower tendency, from the polyester matrix to migrate or during to evaporate out of the polyester from the manufacturing process. Furthermore Such dyes are usually thermally stable and thus for the high Processing temperatures of polyesters more suitable.

Suitable soluble dyes are, for example, those sold by Clariant under the trade name ^® Polysynthren or by Lanxess under the trade name ^® Macrolex. The dyes of Ciba Specialties with the trade name ^® Filester are also suitable.

When Polysynthren Red FBL (anthraquinone derivative, Clariant), Polysynthren Red GFP (Perinon, Clariant), Polysysthrene Blue RBL and RLS (both anthraquinone derivatives, Clariant Co.), Macrolex Red 5B Gran (anthraquinone derivative, Lanxess), Macrolex Red E2G Gran and EG Gran (Perinone, Fa. Lanxess), Macrolex Blue 3R Gran (Anthraquinone derivative, Fa. Lanxess), Macrolex Blue RR Gran (anthraquinone derivative, Fa. Lanxess), Filester Red GA (Perinon, Fa. Ciba Specialties) and Filester Blue GN (phthalocyanine, Ciba Specialties) proved.

By the synergistic effect of the additives barium sulfate, titanium dioxide, optical brightener, and optionally soluble dye in conjunction with an optimized longitudinal stretch ratio the film is white, i.e. less yellowish, and less translucent, i. it has a lower transparency than one with barium sulfate only equipped Foil.

in the Compared to a barium sulfate-only finished film has the film according to the invention at comparable total pigment content a significantly lower number of vacuoles and thus a higher one Density. As a result, the film has a significantly improved dielectric strength on.

The standard viscosity SV (DCE) of the polyethylene terephthalate used as a preferred main component for the film, measured in dichloroacetic acid according to DIN 53728, is preferably between 600 and 1100, in particular between 700 and 1000.

The intrinsic viscosity IV (DCE) is calculated from the standard viscosity SV (DCE) as follows: IV = [η] = 6.907 x 10 -4 SV SVE) + 0.063096 [dl / g]

A inventive film can be both single-layered and multi-layered.

In the multilayered embodiment is the film of at least one core layer (B) and at least a cover layer (A or C) constructed, in particular a three-layered A-B-A or A-B-C structure is preferred.

For this embodiment it is advantageous if the polyester (preferably PET) of the core layer a similar standard viscosity possesses like the polyester of the cover layers, which to the core layer adjoin.

In a particular embodiment can the cover layers also of a polyethylene naphthalate homopolymer or of a polyethylene terephthalate-polyethylene naphthalate copolymer or a compound. The core layer is then preferred made of PET.

In this embodiment The thermoplastics of the outer layers also have a similar one standard viscosity like the polyethylene terephthalate of the core layer.

In the multilayered embodiment are the barium sulfate, the titanium dioxide and the optical brightener and optionally the dye or dyes preferably in the core layer contain. If necessary you can also equipped the outer layers be.

Different as in the single-layered embodiment Here, the concentration of additives refers to the weight the thermoplastic in the layer provided with the additives or the equipped layers.

Of Further is the film according to the invention without environmental impact and without loss of dielectric strength Easily recyclable, making them suitable for use, for example as electrical insulating foil, for short-lived advertising signs, labels or other promotional items, for food packaging, as a foil for medical applications and much more.

The Production of the film according to the invention can be done for example by an extrusion process in an extrusion line.

According to the invention can Barium sulfate, the titanium dioxide, the optical brightener and optionally the dye or dyes already at the thermoplastic raw materials manufacturer be metered or in the film production in the extruder be dosed. The additives can also over Extrusionsmasterbatche be metered. In the production of such Extrusion masterbatches are the additives directly to the polyester added and compounded together. Also the addition of dyes is over this variant possible.

Especially preferred are the addition of barium sulfate, titanium dioxide, the optical brightener and optionally the one or more dyes on the Masterbatch technology. The additives are in a solid carrier material fully dispersed. As carrier materials the thermoplastic itself, e.g. the polyethylene terephthalate or other polymers that are sufficient with the thermoplastic compatible are in question.

Important is that the grain size and the bulk weight similar to the masterbatch the grain size and the bulk weight of the thermoplastic, so that a homogeneous distribution and thus a homogeneous whiteness and thus a homogeneous opacity and dielectric strength can be achieved.

Additional functionality

coating

To improve the adhesion, the polyester film can be provided on one or both sides by known methods with a customary functional coating. For example, acrylates according to WO 94/13476, ethylvinyl alcohols, PVDC, water glass (Na ₂ SiO ₄ ), hydrophilic polyesters such as 5-sodium-sulfoisophthalic acid containing PET / IPA polyesters (EP-A 144 878, US Pat. A 4 252 885 or EP-A 296 620), vinyl acetates (WO 94/13481), polyvinyl acetates, polyurethanes, alkali metal or alkaline earth metal salts of (C ₁₀ -C ₁₈ ) fatty acids, silanes, butadiene copolymers with acrylonitrile or methyl methacrylate, methacrylic acid, acrylic acid or their esters. In addition, the coating may contain conventional additives (eg anti-blocking agents, pH stabilizers) in proportions of about 0.05 to 5.0 wt .-%, preferably 0.1 to 3.0 wt .-%, each based on the weight of the coating liquid , contain.

The substances or compositions mentioned are applied as dilute-preferably aqueous-solution, emulsion or dispersion to one or both surfaces of the film. Subsequently, the solvent is volatilized. The coating is preferably applied in-line, ie during the film production process, expediently before the transverse extension. Particularly preferred is the application after Inverse coatings are applied after longitudinal stretching, usually prior to transverse stretching to achieve sufficient volatilization of the solvent and drying of the coating The dried coatings then have layer thicknesses of preferably 5 to 100 nm, more preferably 20 to 70 nm, in particular 30 to 50 nm.

In a particular embodiment the film is coated with an aminosilane, as described in more detail below becomes.

In U.S. Patent 4,663,228 is the use of N-2-aminoethyl-3-aminopropyltrimethoxysilane described under the trademark Z-6020 by the companies Dow Corning and Worlee. It describes the primer an ionomer resin (salt of an ethylene-methacrylic acid copolymer) on glass and polycarbonate films.

In DE 689 26 896 T2 the use of the coating on polyester films is described. In this case, a polyester film is coated with a hydrolyzed amino-functional silane. The coating serves to directly extrude films without additional corona treatment or additional primer, especially on polyethylene, ethylene copolymer and ionomer or other polymeric films.

None the publications describes the very good enzyme adhesion of the coating, which surprisingly on a biaxially oriented polyester film with the hydrolyzed amino-functional silane coating was detected.

The amino-functional silanes suitable as coating for the purposes of the present invention are in the unhydrolyzed state by the general formula (R ¹ ) _x Si (R ² ) _y (R ³ ) _z wherein R ^{1 is} a functional group having at least one primary amino group such as ethylamine, R ^{2 is} a hydrolyzable group such. A lower alkoxy group, an aceto group or a halide, and R ^{3 represents} an unreactive, nonhydrolyzable group such as a lower alkyl group or a phenyl group; Where (x) is greater than or equal to 1; (y) greater than or equal to 1; (z) is greater than or equal to zero and x + y + z = 4. By lower alkoxy or alkyl group are preferably understood chain lengths of C ₁ to C ₈ .

in the Generally, the aminosilane is hydrolyzed in water and it becomes according to conventional Methods, e.g. by spraying or roll coating, on one or more sides of the oriented Polyester film applied. After drying the Aminosilanbeschichtung you can easily on the polyester film one or more polymers extrude or this as a polyester film with a functional Use coating with very good enzyme adhesion.

silanes are soluble in water after hydrolysis or dispersible, including aminofunctional silanes are particularly readily soluble in water. Hydrolyzed aminosilanes are characterized as polyester films very good adhesion promoter for the extrusion of polymers from, without that while a corona treatment or further coating required is. Surprisingly, it has been found in the present invention that that the enzymes are very good on the surface of such a coated Adhere film.

The in the form of an aqueous solution and / or dispersion according to the invention hydrolyzed coating Aminosilane can be in-line during be applied to one of three stages of film production, namely in the stage before the first stretching, as for example in GB-PS 1,411,564, or after the draw step following the biaxial stretching, but before winding up the Foil. In general, that of the film during stretching or the sufficient final Fed conditioning Heat to Expulsion of water and other volatile components and the Drying of the coating. Would the coating only in Applied to such heating steps would be a separate Drying step required. Preferably, the coating is applied after uniaxial stretching of the film, that is after stretching the film in one direction, up. Preferably, the stretching is carried out initially in longitudinal direction before the coating is applied. The coating can do this for example, by roller coating, spray coating, Schlitzgießerauftrag or dip coating done. In this case, the coating is preferred with gravure rollers. Before coating, you may undergo the uniaxial stretched film of a corona treatment in a corona discharge device. The corona treatment reduces the hydrophobicity of the surface, so that the watery Coating the surface can be better wetted, thereby increasing the adhesion of the coating on the surface improved.

The hydrolyzed aminosilane is used as an aqueous solution with a concentration of preferably 0.2 to 6 wt .-% of hydrolyzed aminosilane applied to the film. Thereafter, to facilitate the hydrolysis, about 0.2% by weight of a weak acid such as acetic acid, phosphoric acid or the like is added thereto. The preferred concentration is such that a coating weight of the dry coating of preferably 0.5 mg / m ² results. However, if the coating is applied off-line, ie in a separate coating process after completion of the film, the coating weight may also be substantially higher, with good results being achieved with dry weights of 50 mg / m ² or more. The coating can be applied to the film on one or both sides; However, it is also possible to provide one side with the described coating and the other side with a different coating.

The Coating composition may additionally contain other ingredients provided that they have the adhesion-promoting effect of the hydrolyzed Do not interfere with aminosilane. This includes e.g. small amounts of colloidal silica, dyes, pH regulators, wetting agents and the like. The coating is on the film surface as a continuous layer before, under this term also coatings with island structure or separate layer areas.

The Production arrears of coated polyester films can be regenerated. The regenerate can be melted again and be re-extruded to produce oriented film.

In another particular embodiment is the film of the invention silicone-coated. Siliconized polymer films are known and available in the stores. The silicone coating is used as a "release" layer for labels or finds, for example for decorative Laminates use. The silicone coating of the siliconized Foil allows adhering to the adhesive-coated side of the labels and The siliconized film can be easily removed by the end user. Siliconized film can also be used as a coating of containers that for the Food contact are intended to be used. In pizza packaging For example, the siliconized film is used. The Foil can through the "release" layer very easily from the melted cheese be deducted on the pizza. The pizza can be easier be served without causing the melted to sticking Cheese with the packaging comes.

A Series of "release" coatings based on silicone are already known and have been described. These silicone coatings include formulations with crosslinkers, Substances that cure with UV light and heat, solvent-free and containing Systems and combinations, such as solvent-free systems, the cure in UV light.

In US 5,350,601 For example, a primer coating containing a glycidoxysilane and a copolyester is described. This primer coating, which is applied under the silicone layer, improves the adhesion and integrity of the silicone layer, which is subsequently applied.

In US 5,350,601 describes a primer coating applied to both sides of the film and a silicone coating which is subsequently applied on both sides. US 5,350,601 does not describe the primer coating only from one side of the film, while the other side is uncoated or provided with another coating.

EP-A 1,013,703 describes a polyester film on one side a silicone coating and on the other side contains a sliding layer or on the other side is uncoated.

The commercially available Hostaphan ^® 3SAC film is equipped with a finished primer coating for subsequent siliconization on both sides. The primer coating includes an isophthalic acid / sodium salt of 5-sulfoisophthalic acid / malonic acid / ethylene glycol copolyester, a glycidoxypropyltrimethoxysilane, a colloidal silica, and sodium lauryl sulfate. The glycidoxypropyltrimethylsilane of Messrs. Dow Corning (Z-6040) and the colloidal silica Nalco ^® 1060. A subsequent coating used in the invention for the siliconization preferably commercially, for example from Wacker Silicones Company, General Electric Silicones and Dow Corning available. An example of a silicone-coated polyester film constituting the Hostaphan ^® 2SLK.

In another particular embodiment Can the film on both sides with the same coating or but also be provided with different coatings.

The polyester film may also be optionally coated with SiO _x , aluminum or Al ₂ O _x . The thickness of this coating is generally in the range of about 10 to 8000 nm, preferably 30 to 4000 nm.

Corona treatment

to Setting further desired Properties, the film may also be corona or flame treated. The treatment intensity is preferably chosen that the surface tension the film in general about 45 mN / m is located.

hydrolysis

In one embodiment, the thermoplastic film can be provided resistant to hydrolysis. As hydrolysis stabilizers are effective compounds that suppress or slow down the hydrolysis of ester bonds. These are, for example, phenolic stabilizers. These include sterically hindered phenols, thiobisphenols, alkylidene bisphenols, alkylphenols, hydroxybenzyl compounds, acylamino-phenols and hydroxyphenylpropionates (in particular (3,5-di-tert-butyl-4-hydroxyphenyl) -propionic acid esters of pentaerythritol or of 1-octadecanol , sold under the name Irganox ^® from Ciba Specialty Chemicals). These compounds are described, for example, in the monograph "Kunststoffadditive" by Gächter and Müller, 2nd ed., Carl Hanser Verlag. The proportion of the phenolic stabilizers is generally from 0.1 to 8.0 wt .-%, preferably 0.2 to 5.0 wt .-%, each based on the weight of the film or the so-equipped layer (in the case of the multilayer Foil).

The phenolic stabilizers mentioned are preferably combined with organic phosphites, especially triaryl phosphites with (for example, available under the name ^® Irgafos 168 of Ciba Specialty Chemicals). These are able to break down peroxides and thus act as secondary stabilizers. The weight ratio of phenolic stabilizers to organic phosphites is generally 10:90 to 90:10. Mixtures of primary and secondary hydrolysis stabilizers are also commercially available, for example under the names ^® Irganox B 561 or ^® Irganox B 225.

On the other hand, compounds which are able to restore bonds broken by hydrolysis are effective as hydrolysis stabilizers. To prepare a Esterbindung again from a hydroxy and a carboxyl group, suitable monomers also include or polymeric carbodiimides (particularly dicyclohexylcarbodiimide or aromatic polymeric carbodiimides, wherein, of the polymeric carbodiimides, those having a molecular weight of 2,000 to 50,000 available ^® under the name Stabaxol P by Rhein Chemie GmbH, Mannheim, are particularly preferred), besides oxazolines. The proportion of these compounds is generally 0.1 to 5.0 wt .-%, preferably 0.2 to 3.0 wt .-%, each based on the weight of the monolayer film or the thus equipped layer of the multilayer film.

A preferred film according to the invention contains both compounds that lower the rate of hydrolysis, as well as compounds that can restore ester bonds. she is particularly resistant to moisture or water. In a preferred embodiment contains the film accordingly 0.1 to 5% by weight of polymeric aromatic carbodiimides and 0.1 to 5% by weight a blend of 30 to 90 wt .-% of an organic phosphite (in particular a triaryl phosphite) and 70 to 10% by weight of a hydroxyphenylpropionate.

wobei
R_E = CH₃ oder H und
m = 1 bis 40, bevorzugt 7 bis 20, besonders bevorzugt 10 bis 16
n = 0 bis 10, bevorzugt 1 bis 4, besonders bevorzugt 2 bis 3,
o = 0 bis 4, bevorzugt 0, ist und
wobei die Reihenfolge der einzelnen Methylen (-CH₂)- (1), Epoxid (CHOCH)- (2) und (CHCH₃)- (3) Gruppen beliebig ist, wobei aber bevorzugt mindestens 2 Methylengruppen (1) und besonders bevorzugt 7 Methylengruppen (1) auf die Carbonylgruppe folgen, bevor eine oder mehrere der Gruppen (2) oder (3) und wieder (1) folgen.Further suitable hydrolysis stabilizers are mixtures of glycerol esters or pure glycerol esters, wherein glycerol esters are described by the following formula: CH ₂ OR ₁ -CHOR ₂ -CH ₂ OR ₃ , where R ₁ , R ₂ and R _{3 are} identical or different and have the following meaning to have:

in which
R _E = CH ₃ or H and
m = 1 to 40, preferably 7 to 20, particularly preferably 10 to 16
n = 0 to 10, preferably 1 to 4, particularly preferred 2 to 3,
o = 0 to 4, preferably 0, and
wherein the order of the individual methylene (-CH ₂ ) - (1), epoxide (CHOCH) - (2) and (CHCH ₃ ) - (3) groups is arbitrary, but preferably at least 2 methylene groups (1) and more preferably 7 Methylene groups (1) follow the carbonyl group before one or more of the groups (2) or (3) and again (1) follow.

Suitable epoxidized fatty acid glycerides of the abovementioned type are, for example, epoxidized soybean oil, epoxidized linseed oil, epoxidized sunflower oil and epoxidized fish oil. The product ^® Polybio Hystab 10 from Schäfer Additivsysteme GmbH (Altrip, DE) has proven particularly suitable.

Of the Proportion of all hydrolysis stabilizers together is preferred 0.2 to 16.0% by weight, preferably 0.5 to 14.0 wt .-%, each based on the weight of Foil or the thus equipped Layer of the multilayer film.

In the multilayered embodiment Preferably, the hydrolysis stabilizer (s) are in the base layer contain. However, you can if necessary, the cover layers and / or possibly existing Interlayers be equipped with hydrolysis stabilizers.

Low shrinkage

Of the Shrink the film leaves itself by appropriate choice of the fixing temperature and the frame geometry over a set a wide range from 0 to about 5% in the longitudinal and transverse directions. Preferably, the film shows a low shrinkage. That means, that in longitudinal as well as in the transverse direction less than 2.5%, preferably less than 2.0%, more preferably less than 1.8%, shrinks when 15 minutes at 150 ° C was heated (DIN 40 634). These shrinkage values can be over the Production process as well as by a subsequent off-line aftertreatment be achieved. In the off-line aftertreatment, the film is largely without pulling through a heating oven guided, being at a temperature in the range of 160 to 210 ° C for 30 seconds exposed for up to 2 minutes. In the manufacturing process, the Shrinkage set by setting the heat setting temperature become. The heat setting temperature is between 180 and 260 ° C, in particular between 220 and 250 ° C.

UV stabilizer

The inventive film can be equipped UV stable be. Light, in particular the ultraviolet portion of solar radiation, d. H. the wavelength range from 280 to 400 nm, induces degradation processes in thermoplastics, as whose consequence is not only the visual appearance by entering Color change or Yellowing changes, but also by the mechanical-physical properties the films made of thermoplastics are extremely negatively influenced. The suppression of these photooxidative degradation processes is of considerable technical and economic importance, otherwise the applications are drastically limited by numerous thermoplastics. For example, polyethylene terephthalates already begin below of absorbing 360 nm of UV light, its absorption decreases below 320 nm and is very pronounced below 300 nm. The maximum absorption is in the range between 280 and 300 nm. In In the presence of oxygen, chain scissions are mainly observed. but no links. Carbon monoxide, carbon dioxide and carboxylic acids the quantitatively predominant Photooxidation products. In addition to the direct photolysis of the ester groups have to still considering oxidation reactions be pulled over Peroxide radicals also result in the formation of carbon dioxide to have. Photooxidation of polyethylene terephthalates may also be via hydrogen abstraction in the a-position of the ester groups to hydroperoxides and their decomposition products as well as associated chain cleavages (H. Day, D. M. Wiles, J. Appl. Polym. Sci. 16 [1972] p. 203).

UV stabilizers, ie UV absorbers as light stabilizers, are chemical compounds that interfere with the physical and chemical processes of light-induced degradation. Soot and other pigments can partially cause a sunscreen. 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. In addition, particularly suitable UV stabilizers are thermally stable in the temperature range from 260 to 300 ° C., ie they do not decompose into cleavage products and do not gase out. Suitable UV stabilizers as light stabilizers, for example, 2-hydroxy-benzophenones, 2-hydroxy-benzotriazole, organo-nickel Ver compounds, salicylic acid esters, cinnamic acid ester derivatives, resorcinol monobenzoates, oxalic anilides, hydroxybenzoic acid esters, benzoxazinones, sterically hindered amines and triazines, with the 2-hydroxybenzotriazoles, the benzoxazinones and the triazines being preferred. It was surprising that the use of UV stabilizers in combination with hydrolysis stabilizers leads to useful films with excellent properties.

Out The literature discloses UV stabilizers which absorb UV radiation and thus provide protection. The expert would then probably have one of these known and commercially available UV stabilizers used, but found that the UV stabilizer has a lack of thermal stability and is at temperatures between 200 and 240 ° C decomposed or outgassed. In order not to damage the film, it would have large amounts (about 10 to 15 wt .-%) need to work on UV stabilizer, so that it effectively absorbs UV light effectively. In these high concentrations, however, the film yellows in a short time Time after production. Also the mechanical properties become negatively influenced. When stretching appear unusual Problems such as breaks due to lack of strength, i. Modulus of elasticity, Die deposits which leads to profile fluctuations, Deposition of UV stabilizer on the rollers, causing impairment the optical properties (strong turbidity, adhesive defect, inhomogeneous Surface) leads, and deposits in the stretching and fixing frames, which are on the film drops. It was therefore surprising that even with low concentrations of UV stabilizers according to the invention excellent UV protection is achieved.

oder 0,1 bis 5,0 Gew.-% 2,2'-Methylen-bis-[6-benzotriazol-2-yl-4-(1,1,2,2-tetramethylpropyl)-phenol] der Formel

oder 0,1 bis 5,0 Gew.-% 2,2'-(1,4-Phenylen)-bis-([3,1]benzoxazin-4-on) der Formel

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

or 0.1 to 5.0% by weight of 2,2'-methylenebis [6-benzotriazol-2-yl-4- (1,1,2,2-tetramethylpropyl) -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 Mischun conditions of at least one of these UV stabilizers with other UV stabilizers are used, wherein the total concentration of light stabilizer preferably between 0.1 and 5.0 wt .-%, particularly preferably in the range of 0.5 to 3.0 wt. %, based on the weight of the finished layer.

flame retardants

In a further embodiment can the film of the invention be equipped flame-retardant. Flame retardant means that the film in a so-called fire protection test the Conditions according to DIN 4102 Part 2 and in particular the conditions complies with DIN 4102 Part 1 and in the building material class B2 and B1 in particular the flame retardant Substances can be classified. The film in this case contains a flame retardant, that preferably over the so-called masterbatch technology directly in film production is added, wherein the proportion of the flame retardant in the range from about 0.2 to 30.0 wt%, preferably 0.5 to 25 wt%, especially preferably from 1.0 to 20.0% by weight, based on the weight of it equipped Layer, lies. The proportion of the flame retardant in the masterbatch is generally 5 to 60 wt .-%, preferably 10 to 50 wt .-%, each based on the total weight of the masterbatch. Suitable flame retardants For example, bromine compounds, chloroparaffins and others Chlorine compounds, antimony trioxide and aluminum trihydrate. The halogen compounds have u. U. the disadvantage that while halogenated by-products can arise. In case of fire can form hydrogen halides. Another disadvantage is the lower one light resistance a so equipped Foil. Other suitable flame retardants are, for example, organic Phosphorus compounds such as carboxyphosphinic acids, their anhydrides and Methanphosphonsäuredimethylester. It is essential that the organic phosphorus compound in the thermoplastic soluble otherwise, the required optical properties are not Fulfills become.

When Particularly suitable organic phosphorus compounds have been shown which are polymerized into the thermoplastic chain, as this outgassing can be avoided in the manufacturing process.

In a particular embodiment contains bis (2-hydroxyethyl) - (6H-dibenz [c, e] [1,2] oxaphosphorin-6-ylmethyl) succinate P-oxide as a flame retardant.

sealability

Where a very good sealability is required and where this property does not have an on-line coating can be achieved, the film of the invention is preferably in three layers constructed and then includes in a particular embodiment the base layer B, a sealable Cover layer A and an optionally sealable cover layer C. Is the Cover layer C also sealable, then the two cover layers are preferably identical.

The preferably by coextrusion applied to the base layer B. sealable Cover layer A is preferably based on polyester copolymers and consists essentially of copolyesters, predominantly from isophthalic acid, Bibenzolcarbonsäure- and / or terephthalic acid units and from ethylene glycol units are composed. The remaining monomer units come from other aliphatic, cycloaliphatic or aromatic diols or dicarboxylic acids, as they may also occur in the base layer. The preferred copolyesters, the desired ones Provide sealing properties are those 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%. Preference is given to copolyesters in which the proportion of ethylene terephthalate 50 to 90 mol% and the corresponding proportion of ethylene isophthalate is 50 to 10 mol%, and are quite preferable Copolyesters in which the proportion of ethylene terephthalate is 60 to 85 mol% and the corresponding proportion of ethylene isophthalate 40 bis 15 mol%.

For the top layer C and for possible intermediate layers can in principle the same polymers are used, which are also in the base layer find use.

The desired Sealing and processing properties of the film according to the invention are the combination of the properties of the copolyester used for the sealable topcoat and the topographies of the sealable Cover layer A and the optionally sealable topcoat C obtained.

The sealing temperature of preferably 110 ° C and the seal strength of preferably at least 1.3 N / 15mm z. B. achieved if for the sealable top layer A, the copolymers described in more detail above are used. The best sealing properties of the film are obtained when the Co polymers no further additives, in particular no inorganic or organic fillers are added. For this case, given a given copolyester, the lowest seal initiation temperature and highest seal seam strengths are obtained. However, in this case, the handling of the film is deteriorated, since the surface of the sealable cover layer A tends to become clogged. The film can be wrapped more difficult and is suitable for further processing on high-speed packaging machines only limited. To improve the handling of the film and the processability, it is necessary to modify the sealable top layer A. This is best done with the help of suitable antiblocking agents of a selected size, which are added in a certain concentration of the sealing layer, in such a way that on the one hand minimizes blocking and on the other hand, the sealing properties are only slightly deteriorated. Antiblocking agents such. For example, silica are described in EP-A-0 515 096.

method

The Polyester films can according to known methods of a polyester raw material with optionally further raw materials and the optical brightener, barium sulfate, titanium dioxide, if appropriate, the dye or dyes and / or further additives, such as flame retardant, UV stabilizer or hydrolysis stabilizer in the quantities described and other customary additives in conventional Amount of preferably 0.1 to 10 wt .-% both as monofilms and also as multilayer, possibly coextruded films with the same or differently shaped surfaces are produced.

In the preferred extrusion process for producing the polyester film, the molten polyester material is extruded through a slot die together with the other constituents (preferably masterbatches) and quenched as a largely amorphous prefilm on a chill roll. This film is then reheated and stretched in the longitudinal and transverse directions or in the transverse and longitudinal direction or in the longitudinal, in the transverse and again in the longitudinal direction and / or transverse direction. The stretching temperatures are preferably T _g + 10 ° C. to T _g + 60 ° C. (T _g = glass transition temperature), the draw ratio of the longitudinal stretching is preferably from 2 to 5, in particular from 2.5 to 4.5, that of the transverse extension 2 to 5, in particular at 3 to 4.5, and that of the optionally performed second longitudinal stretching at 1.1 to 3. The first longitudinal stretching may optionally be carried out simultaneously with the transverse extension (simultaneous stretching). Subsequently, the heat-setting of the film at oven temperatures of preferably 200 to 260 ° C, especially at 220 to 250 ° C. Subsequently, the film is cooled and wound up.

It has completely changed unexpectedly found that a significant factor influencing the optical properties (transparency), the dielectric strength, the density and the formation of vacuoles the process parameters the longitudinal extension are. The process parameters of the longitudinal direction include in particular the longitudinal stretch ratio and the longitudinal stretching temperature. Completely surprising could by varying the longitudinal stretching ratio the transparency, the dielectric strength, the density and the Training of vacuoles are strongly influenced.

By the surprising Combination of the properties mentioned, the films of the invention are suitable for one Variety of different indoor and outdoor applications, for example Electrical insulation applications, for Interior panels, for Trade fair construction and trade fair products, for Displays, for Signs, for Labels, for Protective glazing of machinery and vehicles, in the lighting sector, in shop and shelf construction, as promotional items, laminating medium, for medical Applications and for Food applications.

The The table below (Table 1) summarizes the most important film properties according to the invention once together.

Table 1

The Invention will be explained in more detail below with reference to exemplary embodiments. The Measurement of the individual properties takes place according to the following Standards or procedures.

measurement methods

Light transmission / transparency

Under the light transmission / transparency is the ratio of the total transmitted Light to understand the amount of light.

The Light transmission is measured with the measuring device "Hazegard plus" from Byk-Gardner GmbH, DE, according to ASTM D 1003-00 measured.

Average thickness

wobei gilt:

m

= Masse des untersuchten Folienstückes

l

= Länge der Probe

b

= Breite der Probe

d

= Dichte des untersuchten Materials (für Polyester z.B. 1,395 g/cm³

The average thickness d _F is determined with known length, width and density of a film from the weight. The weight of a film strip prepared on the trimming table, which is taken from the middle of a pattern that goes across the entire width of the roll, is measured. The calculation of d _F is done according to the formula

where:

m

= Mass of the film piece examined

l

= Length of the sample

b

= Width of the sample

d

= Density of the tested material (for polyester eg 1.395 g / cm ³

The individual sample strips are made after trimming on an analytical balance the company Mettler PM 200 (maximum load 200 g). An attached HP Vectra computer ES / 12 takes over after entering machine and roll number all parameters are off the OPUS program and thus calculates the average thickness.

yellow values

The yellowness index YID is given in transmission for according to standard ASTM 1925-70 with the measuring instrument Co lor-Sphere from Byk-Gardner.

measurement conditions for device Color-Sphere Byk-Gardner: The geometry used is d / 8 with gloss, the measuring range is 400 to 700 nm, which is spectral resolution 20 nm, the type of light used is D65, the observer used is 10 °, the diameter of the metering orifice is 30 mm.

whiteness

The degree of whiteness is determined by Berger, with more than 20 layers of film usually being stacked on top of each other. The whiteness is determined by means of the electric remission photometer ^® "ELREPHO" from Zeiss, Oberkochem (DE), standard illuminant C, 2 ° normal observer The whiteness is defined as WG = RY + 3RZ - 3RX.

WG = Whiteness, RY, RZ, RX = corresponding reflection factors when using the Y-, Z and X color filter. As white standard is a compact from barium sulfate (DIN 5033, part 9) used. A detailed Description is e.g. in Hansl Loos "color measurement", publishing house profession and school, Itzehoe (1989), described.

Standard viscosity (SV) and intrinsic viscosity (IV)

The standard viscosity SV was - based on DIN 53726 - 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 from the standard viscosity (SV) as follows: IV = [η] = 6.907 x 10 -4 SV (DCE) + 0.063096 [dl / g]

Surface defects, homogeneous coloring The surface defects and the homogeneous coloring visually determined.

Dielectric strength

The electrical breakdown strength is according to DIN 53481 at AC voltage (50 Hz) as the mean value of 10 measuring points.

density

The Density is determined according to ASTM-D 1505 method C.

The basis for the calculated density is a density of PET of 1.40 kg / dm ³ and for barium sulphate of 4.4 kg / dm ³ and for titanium dioxide of 4.2 for the rutile modification and of 3.9 kg / dm ³ for the anatase modification.

Climate test (wet long-term test)

in the Klimatest (wet long-term test), the film 1000 h at 85 ° C and 95 % relative humidity stored in an autoclave. After this storage becomes the tear strength in longitudinal and transverse direction measured according to ISO 527-1-2. The tear strength must be> 100 N / 15mm, to meet the requirements of the automotive industry.

High temperature strength

The High temperature strength becomes 2.4.9 after 1000 according to IPC TM 650 h annealing at 130 ° C determined in the circulating air dryer. After this annealing, the must tear strength according to ISO 527-1-2 at> 100 N / 15mm to meet the requirements of the automotive industry.

Mechanical properties

Of the Modulus of elasticity and tear strength are used in longitudinal and transverse direction according to ISO 527-1-2 measured.

shrink

Of the Shrinkage is in accordance with DIN 40634 at 150 ° C and 15 minutes residence time.

Weathering (on both sides), UV stability

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

All equipped with UV stabilizer Films were double-sided according to the test specification ISO 4892 1000 hours per page with the Atlas Ci 65 Weather Ometer of the Fa. Atlas weathered and then in terms of mechanical properties, discoloration, surface defects, the cloudiness and the gloss tested.

fire behavior

The Fire behavior was in accordance with DIN 4102 Part 2, building material class B2 and according to DIN 4102 Part 1, building material class B1.

Determination of the sealing temperature (Minimum sealing temperature)

With the sealing device HSG / ET from Brugger (DE) were heat-sealed samples (sealed seam 20 × 100 mm), 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 was sealed. From the sealed samples were test strips cut 15 mm wide. The T-seal strength was like measured in the determination of the seal strength. The sealing temperature is the temperature at which a sealed seam strength of at least 0.5 N / 15 mm is achieved.

Seal strength

to Determination of the seal seam strength two 15 mm wide film strips were superimposed and at 130 ° C, a sealing time of 0.5 s and a sealing pressure of 2 bar (device: Brugger, Type NDS, DE, one side heated sealing jaw) sealed. The seal seam strength was determined by the T-Peel method.

surface tension

The surface measurement is measured by the contact angle measurement method. The determination takes place with the goniometer G1 of the company Krüss GmbH, DE. As a liquid distilled water is used. The sample is taken from the middle taken a layer package and measured directly.

In the following examples and comparative examples are each white-opaque Films produced on the described extrusion line. The Longitudinal stretch ratio is always 1: 3.1.

RS1

Rohstoff, der neben PET 18 Gew.-% Bariumsulfat (Blanc fixe XR-HX, Sachtleben Chemie), 600 ppm optischen Aufheller (Hostalux, Clariant, DE) und 4 ppm blauen Farbstoff (^®Polysynthren Blue RLS, Fa. Clariant) enthält. Der SV-Wert des Rohstoffes liegt bei 810.

RS2

Rohstoff, der neben PET 50 Gew.-% Titandioxid enthält (Rutil-Typ, 0,2 μm Teilchendurchmesser, Fa. Kerr McGee). Der Rohstoff hat einen SV-Wert von ca. 730.

RS3

Rohstoff, der neben PET 4 ppm blauen Farbstoff (^®Polysynthren Blue RLS, Fa. Clariant) sowie 2 ppm roten Farbstoff (^®Macrolex Rot 5B Gran, Fa. Lanxess) enthält, jedoch keinerlei Pigmente („Klarrohstoff"). Der SV-Wert liegt bei 810. Der Rohstoff wurde mittels eines Titan-Polykondensationskatalysators hergestellt.

RS4

Rohstoff, der neben PET 22.500 ppm an Siliziumdioxid (^®Sylobloc, Fa. Grace, DE) als Antiblockmittel enthält.

RS5

Rohstoff, der neben PET 20 Gew.-% des UV-Stabilisators ^®Tinuvin 1577 (Ciba Specialities, Basel, CH) und 10 ppm blauen Farbstoff (^®Polysynthren Blue RLS, Fa. Clariant) enthält.

RS6

Rohstoff, der neben PET 17,2 Gew.-% Bis(2-hydroxyethyl)-(6H-dibenz[c,e][1,2]oxaphosphorin-6-ylmethyl)succinat-P-oxid enthält, das in die Polymerkette einkondensiert ist.

RS7

Copolyester aus 78 Mol.-% Ethylenterephthalat und 22 Mol-% Ethylenisophthalat (hergestellt über das Umesterungsverfahren mit Mn als Umesterungskatalysator, Mn-Konzentration: 100 ppm).

RS8

Rohstoff, der neben PET 20 Gew.-% ^®Polybio Hystab 10 (Schäfer Additiv-Systeme GmbH, Altrip, DE) enthält.

RS9

Analog RS3, enthält zusätzlich 1000 ppm des Hydrolysestabilisators ^®Irganox 1010 (Ciba Specialities, Basel, CH).

The following raw materials were used for the production of the white-opaque films:

RS1

Raw material containing, in addition to PET, 18% by weight of barium sulfate (Blanc fixed XR-HX, Sachtleben Chemie), 600 ppm of optical brightener (Hostalux, Clariant, DE) and 4 ppm of blue dye ( ^® Polysynthren Blue RLS, Clariant). The SV value of the raw material is 810.

RS2

Raw material containing 50 wt .-% titanium dioxide in addition to PET (rutile type, 0.2 micron particle diameter, Fa. Kerr McGee). The raw material has an SV value of about 730.

RS3

Raw material, which in addition to PET 4 ppm blue dye ( ^® Polysynthren Blue RLS, Fa. Clariant) and 2 ppm red dye ( ^® Macrolex Red 5B Gran, Fa. Lanxess), but no pigments ("clear raw material") .The SV value is 810. The raw material was produced by means of a titanium polycondensation catalyst.

RS4

Raw material, which in addition to PET contains 22,500 ppm of silicon dioxide ( ^® Sylobloc, Grace, DE) as antiblocking agent.

RS5

Raw material containing, in addition to PET, 20% by weight of the UV stabilizer ^® Tinuvin 1577 (Ciba Specialties, Basel, CH) and 10 ppm of blue dye ( ^® Polysynthren Blue RLS, Clariant).

RS6

Raw material which, besides PET, contains 17.2% by weight of bis (2-hydroxyethyl) - (6H-dibenz [c, e] [1,2] oxaphosphorin-6-ylmethyl) succinate P-oxide, which is incorporated into the polymer chain is condensed.

RS7

Copolyester of 78 mole% ethylene terephthalate and 22 mole% ethylene isophthalate (prepared via the transesterification process with Mn as transesterification catalyst, Mn concentration: 100 ppm).

RS8

Raw material, which in addition to PET contains 20% by weight of ^® Polybio Hystab 10 (Schäfer Additiv-Systeme GmbH, Altrip, DE).

RS9

Analog RS3, additionally contains 1000 ppm of the hydrolysis stabilizer ^® Irganox 1010 (Ciba Specialties, Basel, CH).

Example 1 (B1)

A 50 μm thick film was produced with the following recipe:
20% by weight of clear raw material RS3
50 wt .-% species-specific regenerate, which was prepared from inherent accumulated Folienverschnitt
22 wt .-% of the raw material RS1
8% by weight of the raw material RS2

In Contains sum the film thus 8 wt .-% barium sulfate, 8 wt .-% titanium dioxide and 264 ppm optical brightener and red and blue dye.

After longitudinal stretching, the film is coated on one side by means of reverse gravure-roll coating processes with an aqueous dispersion containing, in addition to water, 4.2% by weight of hydrophilic polyester (5-Na-sulfoisophthalic acid-containing PET / IPA polyester, ^® SP41, Ticona, US), 0.15 wt .-% colloidal silica (Nalco ^® 1060, German Nalco Chemicals, DE) as an antiblocking agent and 0.15 wt .-% ammonium carbonate (Merck, DE) 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 (B2)

A 50 μm thick film was produced with the following recipe:
17% by weight of clear raw material RS3
50 wt .-% species-specific regenerate, which was prepared from inherent accumulated Folienverschnitt.
22 wt .-% of the raw material RS1
8% by weight of the raw material RS2
3% by weight of the raw material RS5

In Contains sum the film thus 8 wt .-% barium sulfate, 8 wt .-% titanium dioxide, 264 ppm optical brightener, 1.2 wt.% UV stabilizer and red and blue dye.

Example 3 (B3)

A 50 μm thick film was produced with the following recipe:
22 wt .-% of the raw material RS1
8% by weight of the raw material RS2
50 wt .-% species-specific regenerate, which was prepared from inherent accumulated Folienverschnitt.
20 wt .-% of the raw material RS6

In Contains sum the film thus 8 wt .-% barium sulfate, 8 wt .-% titanium dioxide, 264 ppm optical brightener, 6.9 wt .-% flame retardant and red and blue dye.

Example 4 (B4)

A 50 μm thick ABC film was produced with the following recipe:
Coex layer A, 2 μm thick
93% by weight of the raw material RS3
7% by weight of the raw material RS4
Base layer B, 46 μm thick
Identical with recipe from Example 1
Coextreme C, 2 μm thick
97 wt .-% of the raw material RS7
3% by weight of the raw material RS4

Example 5 (B5)

A 50 μm thick film was produced with the following recipe:
20% by weight of clear raw material RS9
50 wt .-% species-specific regenerate, which was prepared from inherent accumulated Folienverschnitt.
22 wt .-% of the raw material RS1
8% by weight of the raw material RS2

In Contains sum the film thus 8 wt .-% barium sulfate, 8 wt .-% titanium dioxide and 264 ppm optical brightener, 400 ppm Irganox 1010 and red and blue dye.

Example 6 (B6)

A 50 μm thick film was produced with the following recipe:
10% by weight of clear raw material RS3
50 wt .-% species-specific regenerate, which was prepared from inherent accumulated Folienverschnitt.
22 wt .-% of the raw material RS1
8% by weight of the raw material RS2
10% by weight of the raw material RS8

In Contains sum the film thus 8 wt .-% barium sulfate, 8 wt .-% titanium dioxide, 264 ppm optical brightener, 4 wt .-% hydrolysis stabilizer and red and blue dye.

Example 7 (B7)

foil from Example 1 is in a heating oven largely zuglos at a temperature of 200 ° C and a Retention time of 60 seconds aftertreated.

Example 8 (B8)

Analogous Example 2 becomes a 50 μm thick, white-opaque, UV-stabilized film produced. The film is corona treated on one side. The intensity is chosen that the surface tension is> 45 mN / m.

Comparative Example 1 (VB1)

A 50 μm thick film was produced with the following recipe:
34% by weight of clear raw material RS3
50 wt .-% species-specific regenerate, which was prepared from inherent accumulated Folienverschnitt.
16% by weight of the raw material RS2

In sum, the film thus contains 16% by weight of titanium dioxide and red and blue dye, but none Barium sulfate and no optical brightener.

Comparative Example 2 (VB2)

A 50 μm thick film was produced with the following recipe:
3% by weight of clear raw material RS3
50 wt .-% species-specific regenerate, which was prepared from inherent accumulated Folienverschnitt.
44 wt .-% of the raw material RS1
3% by weight of the raw material RS5

In Contains sum the film thus 16 wt .-% barium sulfate, UV stabilizer, optical Brightener and red and blue dye, but no titanium dioxide.

Comparative Example 3 (VB3)

It was prepared in analogy to Comparative Example 2, a 50 micron thick film with the following recipe:
6% by weight of clear raw material RS3
50 wt .-% species-specific regenerate, which was prepared from inherent accumulated Folienverschnitt.
44 wt .-% of the raw material RS1

In Contains sum the film thus 16 wt .-% barium sulfate, optical brightener as well red and blue dye but no titania and no UV stabilizer.

The The most important properties of the films mentioned are in the following Table 2 summarized.

there shows that the films according to VB1 to VB3 in particular in the combination of the properties of transparency, Yellowness and dielectric strength deficiencies over the inventive films B1 to B8.

Claims (23)

White opaque Foil with at least one additional functionality containing a crystallizable thermoplastic, barium sulfate and titanium dioxide and at least one optical brightener. A film according to claim 1, characterized in that the proportion of crystallizable thermoplastic greater than 50% by weight, based on the total weight of the film. Foil according to claim 1 or 2, characterized that it contains at least one thermoplastic-soluble dye. A film according to one or more of claims 1 to 3, characterized in that as a crystallizable thermoplastic a crystallizable thermoplastic polyester is used. A film according to one or more of claims 1 to 4, characterized in that the thermoplastic polyester units of ethylene glycol and terephthalic acid and / or units Isophthalic acid, naphthalene-1,5-dicarboxylic acid or Naphthalene-2,6-dicarboxylic having. A film according to one or more of claims 1 to 5, characterized in that as thermoplastic polyester Polyethylene terephthalate, polyethylene naphthalate or mixtures thereof be used. A film according to one or more of claims 1 to 6, characterized in that the film 1 to 20 wt .-% barium sulfate and 1 to 20 wt .-% titanium dioxide, each based on the Weight of the pigmented layer thermoplastic. A film according to one or more of claims 1 to 7, characterized in that the film 1 to 25000 ppm optical Contains brightener, based on the weight of the thermoplastic of the thus equipped layer. A film according to one or more of claims 1 to 8, characterized in that the film 1 to 100 ppm in the thermoplastic soluble Contains dyes, based on the weight of the thermoplastics containing the dyes. A film according to one or more of claims 1 to 9, characterized in that the film next to a base layer B has one or two outer layers which are the same or different could be. A film according to one or more of claims 1 to 10, characterized in that the cover layers polyethylene terephthalate, Polyethylene naphthalate or a polyethylene terephthalate-polyethylene naphthalate copolymer contain. A film according to one or more of claims 1 to 11, characterized in that the film at a thickness of 50 microns, a transparency from 1 to 20%. A film according to one or more of claims 1 to 12, characterized in that the film at a thickness of 50 microns a yellow value YID from 1 to 15. A film according to one or more of claims 1 to 13, characterized in that the film has a whiteness of greater than 85%. A film according to one or more of claims 1 to 14, characterized in that the film at a thickness of 50 microns an electric Dielectric strength greater than 150 kV / mm. A film according to one or more of claims 1 to 15, characterized in that the film has a void index of greater than 87%. Film according to one or more of claims 1 to 16, characterized in that the film has a density of greater than 1.39 kg / dm ³ . A film according to one or more of claims 1 to 17, characterized in that the film to achieve an additional functionality one or both sides an adhesive coating, a coating with a Aminosilane or a coating with silicone has. A film according to one or more of claims 1 to 18, characterized in that the film to achieve an additional functionality Corona treated, hydrolysis resistant equipped, UV-stabilized or flame-retardant. A film according to one or more of claims 1 to 19, characterized in that the film in the longitudinal and transverse directions a Has shrinkage of less than 2.5%, when 15 min. is heated to 150 ° C. A film according to one or more of claims 1 to 20, characterized in that the film has at least one sealable cover layer having. Process for producing a film according to one or more of the claims 1 to 21 comprising the steps a) producing a film Extrusion or coextrusion b) biaxial stretching of the film and c) Thermofixing the stretched film Use of a film after one or more the claims 1 to 21 for Electrical insulation applications, interior trim, protective glazing, Signs, labels, medical and food-technical purposes.