WO2001053390A1

WO2001053390A1 - Amorphous, transparent tinted, thermoformable film which absorbs uv-light, a method for the production thereof and the use of the same

Info

Publication number: WO2001053390A1
Application number: PCT/EP2001/000176
Authority: WO
Inventors: Ursula Murschall; Ulrich Kern; Günther Crass
Original assignee: Mitsubishi Polyester Film Gmbh
Priority date: 2000-01-20
Filing date: 2001-01-10
Publication date: 2001-07-26
Also published as: DE10002152A1

Abstract

The invention relates to an amorphous, transparent tinted, thermoformable film which absorbs UV-light, consisting of a crystallisable thermoplastic whose thickness ranges between 30 and 1000 νm, to a method for the production thereof and to the use of the same. The film contains at least one UV-absorber which can be dissolved in the thermoplastic and a soluble dye. Said film is characterised by excellent optical characteristics, a high level of light transmission in the wavelength range ≥ 400 nm and by the absorption of short-wave UV-light in the wavelength range below 380 nm.

Description

Amorphous, transparently colored, UV light absorbing, thermoformable film, a process for its production and its use

The invention relates to an amorphous, transparently colored, UV light absorbing thermoformable film made of a crystallizable thermoplastic, the thickness of which is in the range from 30 to 1000 μm, a process for its production and its use. The film contains at least one thermoplastic-soluble dye and a soluble UV absorber and is characterized by good optical properties, high light transmission in the wavelength range from> 400 nm, preferably 420 to 800 nm, by economical thermoformability and by the absorption of short-wave UV -Lights in the wavelength range of less than 380 nm.

Transparent and transparent colored polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC) and polyethylene terephthalate (PET) plates with thicknesses greater than 1 mm are well known. These plates are uneconomical to produce on slow-running machines. The plates are inflexible, cannot be wound up, are only available by the meter and coated with a protective film. The transportation of these huge plates is uneconomical. In addition, these plates show a low light transmission, i. H. they are cloudy and have an unsatisfactory optical surface quality. The plates are not equipped with antiblocking and lubricants, so that they stick to rollers during the production process and thus show defects on the surface. The sheets can only be thermoformed as a cut and under uneconomical conditions.

Transparent films are also known. The films are usually oriented and therefore have a crystallinity of between 30 and 50%. These foils are crystalline or semi-crystalline structures. These films also absorb not the short-wave, aggressive UV light. From a wavelength of 280 nm, these foils let UV light through.

The films contain no soluble dye.

The object of the present invention is to avoid the disadvantages of the prior art described.

The invention therefore relates to an amorphous, transparently colored, UV light-absorbing, thermoformable film with a thickness in the range from 30 μm to 1000 μm, which contains a crystallizable thermoplastic as the main component and which is characterized in that it additionally contains at least one in the thermoplastic contains soluble UV stabilizer and at least one soluble dye, also a process for their preparation and their use.

The film according to the invention has both good optical properties and a high light transmission in the wavelength range from> 400, preferably 420 to 800 nm, has a barrier against the short-wave, aggressive UV light in the wavelength range from <380 nm and combines a high combination UV stability with a colored appearance that can be used effectively for advertising.

The good optical properties included, for example, high light transmission, low haze, high surface gloss and a homogeneous, transparent color.

Thermoformability means that the film can be thermoformed or thermoformed on commercially available thermoforming machines without complex pre-drying to form complex and large-area shaped articles. A high UV stability means that the film and the moldings made from it are extremely little damaged by sunlight or other UV radiation, making them suitable for outdoor and critical indoor applications. The film or the molded body should not yellow during several years of external use and should not show any cracks or embrittlement of the surface.

A barrier against UV light means that the film completely absorbs the aggressive short-wave radiation, which is responsible, for example, for fat oxidation in foods, in the wavelength range <380 nm.

The film according to the invention contains a crystallizable thermoplastic as the main component. Suitable crystallizable or partially crystalline thermoplastics are, for example, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, with polyethylene terephthalate being preferred.

According to the invention, crystallizable polyester is understood to mean crystallizable homopolymers, crystallizable copolymers, crystallizable compounds (mixtures), crystallizable recyclate and other variations of crystallizable thermoplastics.

The film according to the invention can be either single-layer or multi-layer. It can also be coated with various copolyesters or adhesion promoters. For the purpose of economical production, the film contains the antiblocking and lubricants that are customary for films.

It contains at least one UV stabilizer as a light stabilizer, the concentration of the UV stabilizer preferably in the range from 0.01% by weight to 5.0% by weight, in particular in the range from 0.1% by weight to 3 % By weight, based on the weight of the layer of the crystallizable thermoplastic, is. Light, in particular the ultraviolet portion of solar radiation, ie the wavelength range from 280 to 400 nm, initiates degradation processes in thermoplastics, as a result of which not only the visual appearance changes as a result of color change or yellowing, but also negatively influences the mechanical-physical properties become.

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.

Polyethylene terephthalates, for example, begin to absorb UV light below 360 nm, their absorption increases considerably below 320 nm and is very pronounced below 300 nm. The maximum absorption is between 280 and 300 nm.

In the presence of oxygen, mainly chain cleavages are observed, but no cross-links. Carbon monoxide, carbon dioxide and carboxylic acids are the predominant quantities of photooxidation products. In addition to the direct photolysis of the ester groups, oxidation reactions must also be considered, which also result in the formation of carbon dioxide via peroxide radicals.

The photooxidation of polyethylene terephthalates can also lead to hydroperoxides and their decomposition products and the associated chain cleavages via elimination of hydrogen in the α-position of the ester groups (H. Day, D. M. Wiles: J. Appl. Polym. Sei 16, 1972, page 203).

UV stabilizers or UV absorbers as light stabilizers are chemical compounds that are involved in the physical and chemical processes of light-induced degradation can intervene. Soot and other pigments can partially protect against light. However, these substances are unsuitable for transparent films because they lead to discoloration or color change. For transparent, matt films, only organic and organometallic compounds are suitable which give the thermoplastic to be stabilized no or only an extremely slight color or color change, ie which are soluble in the thermoplastic.

UV stabilizers suitable as light stabilizers for the purposes of the present invention are UV stabilizers which absorb 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. These are particularly suitable if they are thermally stable in the temperature range from 260 to 300 ° C. H. do not decompose and do not lead to outgassing. Suitable UV stabilizers as light stabilizers are, for example, 2-hydroxybenzophenones, 2-hydroxybenzotriazoles, organo-nickel compounds, salicylic acid esters, cinnamic acid ester derivatives, resorcinol monobenzoates, oxalic acid anilides, hydroxybenzoic acid esters, sterically hindered amines and triazines, the 2-hydroxybenzotriazoles being preferred.

Furthermore, the amorphous film according to the invention contains a dye which is soluble in the thermoplastic, the concentration of the soluble dye preferably being in the range from 0.1% by weight to 20.0% by weight, in particular in the range from 0.5 to 10% 0 wt .-%, based on the weight of the crystallizable thermoplastic, is.

Soluble dye is understood to mean substances that are molecularly dissolved in the polymer (DIN 55949).

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

Coloring with dye is a solution process. As a result of this solution process, the dye is molecularly dissolved, for example, in the crystallizable thermoplastic. Such coloring is referred to as transparent, translucent, translucent or opal.

Of the various classes of soluble dyes, the fat and aromatic soluble dyes are particularly preferred. These are, for example

Azo and anthraquinone dyes. They are particularly suitable e.g. for coloring

PET, because due to the high glass transition temperatures of PET, the migration of the

Dye is restricted.

(Literature J. Koerner: Soluble dyes in the plastics industry in "VDI-Gesellschaft Kunststofftechnik:": Coloring plastics, VDI-Verlag, Düsseldorf 1975).

Examples of suitable soluble dyes are: C.I. Solventgelb 93 (a pyrazolone derivative), C.I. Solvent Yellow 16 (a fat-soluble azo dye), Fluorol Green Gold (a fluorescent polycyclic dye), C.I. Solvent red 1 (an azo dye), azo dyes such as Thermoplastrot BS, Sudanrot BB, C.I. Solvent red 138 (an anthraquinone derivative), fluorescent benzopyran dyes such as fluorol red GK and fluorol orange 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.

It is essential to the invention that the crystallizable thermoplastic has a diethylene glycol content of> 1.0% by weight, preferably> 1.2% by weight, in particular> 1.3% by weight and / or a polyethylene glycol content of> 1.0% by weight , preferably> 1, 2% by weight, in particular> 1.3% by weight and / or an isophthalic acid content of 3% by weight to 10% by weight.

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) oxyphenol of the formula

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

In a preferred embodiment, mixtures of these two UV stabilizers or mixtures of at least one of these two UV stabilizers with other UV stabilizers can also be used, the total concentration being Light stabilizers are preferably between 0.01% and 5.0% by weight, based on the weight of crystallizable polyethylene terephthalate.

It is completely surprising that the use of the above-mentioned UV stabilizers in conjunction with the soluble dye in films leads to the desired result.

However, if other commercially available UV stabilizers are used that absorb the UV light and thus generally offer protection, it is found that the film quickly turns yellow after weathering and thus the color is shifted, - the UV stabilizer has a poor thermal stability and yourself at

Temperatures between 200 ° C and 240 ° C decomposed or outgassed, large quantities (approx. 10 to 15% by weight) UV stabilizer must be incorporated so that the UV light is absorbed and the film is not damaged.

At these high concentrations, the film already has a yellow appearance after production, with yellowness index differences (YID) around 25. Furthermore, the mechanical properties are negatively affected.

It was therefore more than surprising that even low concentrations of the UV stabilizer used according to the invention and the use of the soluble dye provided excellent UV protection. It was very surprising that with this excellent UV protection the yellowness of the film does not change compared to a non-stabilized film within the scope of the measurement accuracy, - no outgassing, no nozzle deposits, which means that the film has an excellent appearance and an excellent profile and has an excellent flatness, the UV-stabilized film is characterized by excellent running reliability, so that it is reliable and stable on high speed film lines up to can be produced reliably at speeds of 120 m / min.

This means that the film is also economically viable.

It was also very surprising that the film absorbs the aggressive, short-wave light in the wavelength range up to 380 nm, preferably up to 360 nm. H. does not let through.

Furthermore, it is very surprising that the regrind can also be used again without negatively influencing the color value of the film.

At least one surface layer can be coated or vapor-coated with ethylene-vinyl alcohol copolymer, ethyl-vinyl alcohol, polyvinyl alcohol or polyvinylidene dichloride, ethylene-vinyl alcohol copolymer being preferred. In a preferred embodiment, the thickness of the barrier layer is in the range from 10 nm to 8000 nm, in particular from 30 to 4000 nm.

The barrier layer serves as a gas, in particular oxygen or aroma barrier and has an oxygen permeability of <10 cm ³ / (m ² -24 hbar). It is based on an ethylene-vinyl alcohol copolymer with an ethylene content of 15-60 mol% and a degree of saponification of at least 90 mol%, preferably greater than 96 mol%, in particular about 99 mol%. These copolymers include e.g. B. ethylene-propylene-vinyl alcohol copolymers and reaction products of ethylene-vinyl alcohol copolymers with lower aldehydes or ketones, as described in DE-OS 29 31 035 or US Pat. No. 4,212,956.

The ethylene-vinyl alcohol copolymers can contain water during the extrusion, preferably in an amount of 1 to 10% by weight. To achieve a high Orientation effect and thus a good gas barrier, however, it is preferable if the water content is less than 5%, preferably less than 3.5%, in particular even less than 2% by weight, or approaches zero.

The barrier layer based on ethylene-vinyl alcohol copolymers can contain monomeric, oligomeric or polymeric substances to reduce the crystallinity. The amount added depends on the tolerance, i.e. H. the incorporability and miscibility with the main component and the influence on oxygen permeability.

Examples of such products are substances containing hydroxyl and carbonyl groups, such as trimethylolpropane, neopentyl glycol and polyethylene glycols, and in particular substances which in turn already have barrier properties, e.g. As polyvinyl alcohol or polyamides, mixtures of ethylene-vinyl alcohol copolymers and 10 to 50 wt .-% polyvinyl alcohol with a degree of hydrolysis of> 80, in particular greater than / equal to 88 mol%, and a viscosity of 0.4 10 ^"2 to 4 10 ^"2 , especially 0.4. 10 ^"2 to 1 ^■ 10 ^{" 2} Pa ^■ s are particularly advantageous.

The barrier layer based on ethylene-vinyl alcohol copolymers may contain further additives in the form of monomeric, oligomeric or polymeric substances which promote adhesion to the adjacent layers.

For the purposes of the present invention, amorphous film means films which, although the crystallizable thermoplastic has a crystallinity of 20% to 65%, preferably 30% to 50%, are not crystalline. Non-crystalline, ie essentially amorphous, means that the degree of crystallinity is generally below 5%, preferably below 2%. Such a film is essentially in the unoriented state. The thermoforming process usually includes the steps of predrying, heating, molding, cooling, demolding, tempering. During the thermoforming process, it was found that the films according to the invention can surprisingly be thermoformed without prior predrying. This advantage compared to thermoformable polycarbonate or polymethyl methacrylate films, which require pre-drying times of 10 - 15 hours, depending on the thickness, at temperatures from 100 ° C to 120 ° C, drastically reduces the costs of the forming process. It was also very surprising that the detail reproduction of the molded body is excellent. The film can also be fed to the thermoforming process, for example as a roll.

The surface gloss measured according to DIN 67530 (measuring angle 20 °) is greater than 120, preferably greater than 140, the light transmission L ^* , measured according to ASTM D 1003, is more than 82%, preferably more than 84% and the haze of the film, measured according to ASTM D 1003, is less than 10%, preferably less than 8%, which is surprisingly good for the UV stability achieved.

The standard viscosity SV (DCE) of the thermoplastic measured in dichloroacetic acid according to DIN 53728 is 600 to 1000, preferably 700 to 900.

It was more than surprising that the films according to the invention can be thermoformed economically on commercially available deep-drawing systems and provide excellent detail reproduction due to a higher diethylene glycol content and / or polyethylene glycol content and / or IPA content compared to the standard thermoplastic.

The transparent colored thermoplastic film, which contains at least one UV stabilizer and a dye, can be either single-layer or multi-layer.

In the multilayer embodiment, the film is composed of at least one core layer and at least one cover layer, in particular a three-layer one ABA or ABC structure is preferred. In the multilayer case, one of the two outer layers, which can be corona-treated, can be vapor-coated with ethylene-vinyl alcohol copolymer, ethyl-vinyl alcohol, polyvinyl alcohol or polyvinylidene dichloride. The cover layers are formulated with the antiblocking agents and / or lubricants customary for thermoplastic films.

For this embodiment it is essential that e.g. The thermoplastic of the core layer has a standard viscosity similar to that of the thermoplastic of the cover layer (s) which adjoins the core layer.

In a particular embodiment, the cover layers can also consist of a polyethylene naphthalate homopolymer or of a polyethylene terephthalate-polyethylene naphthalate copolymer or compound.

In this embodiment, the thermoplastics of the cover layers also have a standard viscosity similar to that of the thermoplastic of the core layer.

In the multilayer embodiment, the UV stabilizer and the dye are preferably contained in the top layer or layers. However, the core layer can also be equipped with UV stabilizers and dye as required.

Unlike the single-layer embodiment, the concentration of the stabilizer (s) and the concentration of the dye (s) refer to the weight of the thermoplastic in the layer equipped with UV stabilizer (s) and dye.

Quite surprisingly, weathering tests according to the test specification ISO 4892 with the Atlas CI65 Weather Ometer have shown that in the case of a three-layer It is quite sufficient for the film to equip the 0.5 μm to 10 μm thick cover layers with UV stabilizers in order to achieve improved UV stability.

As a result, the multilayer films according to the invention produced using the known coextrusion technology become economically interesting in comparison with the completely UV-stabilized monofilms, since significantly less UV stabilizer is required for comparable UV stability.

The film can also be provided on at least one side with a scratch-resistant coating, with a copolyester or with an adhesion promoter.

Weathering tests have shown that the films according to the invention themselves

Weathering tests after an estimated 5 to 7 years of outdoor use generally show no yellowing or color change in the direction of yellow, no embrittlement, no loss of gloss on the surface and no cracking on the surface.

During the production of the film, it was found that the UV-stabilized film can be produced reliably. Furthermore, no outgassing of the UV stabilizer was found in the production process, which is essential to the invention, since most UV stabilizers at annealing temperatures above 260 ° C. give off unpleasant outgassing and are therefore unsuitable.

Furthermore, the film according to the invention can be easily recycled without environmental pollution and without a noticeable loss of the mechanical properties, which makes it suitable, for example, for use as a short-lived article.

The following process parameters have generally proven to be suitable for thermoforming: Process step film according to the invention

Predrying is not necessary

Mold temperature ° C 100 to 140

Heating time per 10 μm film thickness <5 sec per 10 μm film thickness film temperature during forming ° C 100 to 160

Possible stretch factor 1, 5 to 4.0

Excellent detail reproduction

Shrinkage (shrinkage)% <1, 5

Since the film also absorbs the short-wave UV light in the wave range from 260 nm to 360 nm, in particular up to 380 nm, the film offers a barrier against the aggressive short-wave light which, for. B. causes the dreaded fat oxidation in food. Consequently, the film according to the invention is outstandingly suitable as packaging film for sensitive goods on packaging machines in the vertical and horizontal range (vFFs and hFFs machines).

Furthermore, the film is suitable as a composite film, the composite consisting of the film according to the invention, optionally with ethylene-vinyl alcohol copolymer, ethyl-vinyl alcohol, polyvinyl alcohol or polyvinylidene dichloride coating and a second film. This second film can e.g. can also be a UV-stable thermoplastic film, a standard thermoplastic film or a polyolefin film.

The second film can be single-layer or multi-layer and, like the first UV-stable film, can be amorphous, i. H. be disoriented and can have at least one sealing layer. The second film can be connected to the first UV-stable barrier film according to the invention with or without adhesive.

The thickness of this second film is preferably in the range from 30 to 500 μm. The composite film is generally obtained by laminating or laminating the two films to one another, with or without an intermediate layer of adhesive, by passing them between rollers heated to 30 ° C. to 90 ° C.

The two films can be connected to one another, for example, with or without an adhesive layer, by a lamination process. However, it is also possible, for example, to apply the second, colored layer to the first, coated layer by in-line coating (melt extrusion onto an existing layer).

If adhesives are used, they are applied to a film surface by known methods, in particular by application from solutions or dispersions in water or organic solvents. The solutions usually have an adhesive concentration of 5 to 40% by weight to give an amount of adhesive of 1 to 10 g / m ² on the film.

Adhesives made from thermoplastic resins, such as cellulose esters and ethers, alkyl and acrylic esters, polyamides, polyurethanes or polyesters, or from thermosetting resins, such as epoxy resins, urea / formaldehyde, phenyl / formaldehyde or melamine / - Formaldehyde resins, or consist of synthetic rubbers.

Suitable solvents for the adhesive are e.g. Hydrocarbons such as ligroin and toluene, esters such as ethyl acetate or ketones such as acetone and methyl ethyl ketone.

The film according to the invention can be produced, for example, by known extrusion processes in an extrusion line. According to the invention, the light stabilizer and the soluble dye can be metered in at the thermoplastic raw material manufacturer or can be metered into the extruder during film production.

It is preferred to add the light stabilizer and the dye via masterbatch technology. The additives are first fully dispersed in a solid carrier material. The thermoplastic itself comes as carrier materials, e.g. B. the polyethylene terephthalate or other polymers that are sufficiently compatible with the thermoplastic, in question. After metering into the thermoplastic for film production, the components of the masterbatch melt during the extrusion and are thus dissolved in the thermoplastic.

The concentrations of the individual additives in addition to the thermoplastic in the masterbatch are: UV absorber 2.0 to 50.0% by weight, preferably 5.0 to 30.0% by weight, optical brightener 0.05 to 5.0% by weight .-%, preferably 0.1 to 2.0 wt .-% and soluble dye 1, 0 to 20.0 wt .-%, preferably 1, 5 to 15.0 wt .-%, the sum of the components always Is 100% by weight.

It is important with masterbatch technology that the grain size and bulk density of the masterbatch is similar to the grain size and bulk density of the thermoplastic, so that homogeneous distribution and thus homogeneous UV stabilization can take place.

The films according to the invention can, according to the extrusion process, consist of a thermoplastic raw material with optionally further raw materials, the UV stabilizer, the dye and / or other conventional additives in a customary amount of 0.1 to a maximum of 10.0% by weight both as monofilms and also as multilayer, optionally coextruded films with the same or differently shaped surfaces are produced, one surface being pigmented, for example, and the other surface containing no pigment. Likewise, one or both surfaces of the film can be provided with a conventional functional coating by known methods.

The polymers or raw material mixtures are fed to an extruder or, in the case of multilayer films, to a plurality of extruders. Any foreign bodies or impurities that may be present can be filtered out of the polymer melt before extrusion. The melt (s) are then formed into flat melt films in a mono nozzle or, in the multilayer case, in a multilayer nozzle, and in the multilayer case are layered one on top of the other. Subsequently, the monofilm or the multilayer film is quenched with the help of a cooling roll and considered largely amoφhe, i.e. unoriented film solidified. The cooled, amorphous film is then hemmed and wound up.

The film can also be coated on at least one of its surfaces, so that the coating on the finished film has a thickness of 5 to 100 nm, preferably 20 to 70 nm, in particular 30 to 50 nm. The coating is preferably applied in-line, ie during the film production process, expediently after solidification. It is particularly preferred to apply the “reverse gravure roll coating” method, in which the coatings can be applied extremely homogeneously in the layer thicknesses mentioned. The coatings are preferably applied as a solution, suspension or dispersion, in particular as an aqueous solution, suspensions or dispersions. The coatings mentioned give the film surface an additional function, for example making the film sealable, printable, metallizable, sterilizable, antistatic or, for example, improve the aroma barrier or enable adhesion to materials that would otherwise not adhere to the film surface (e.g. photographic emulsion). Examples of substances / compositions that provide additional functionality:

Acrylates as described, for example, in WO 94/13476, ethyl vinyl alcohols, PVDC, water glass (Na ₂ Si0 ₄ ), hydrophilic polyesters (5-sodium sulfoisophthalic acid-containing PET / IPA polyesters as described, for example, in EP-A-0 144 878 , US-A-4,252,885 or EP-A-0296620, vinyl acetates as described, for example, in WO 94/13 481, polyvinyl acetate, polyurethanes, alkali or alkaline earth metal salts of C ₁₀ -C ₁₈ fatty acid, butadiene copolymers with acrylonitrile or methyl methacrylate, methacrylic acid , Acrylic acid or its esters.

The substances / compositions mentioned are applied as a dilute solution, emulsion or dispersion, preferably as an aqueous solution, emulsion or dispersion, to one or both surfaces of the film and then the solvent is evaporated. If the coatings are applied in-line, a heat treatment after solidification is usually sufficient to volatilize the solvent and to dry the coating. The dried coatings then have the desired layer thicknesses mentioned.

Can further of the sheets - preferably in an off-line process with metals wwiiee AAlluummiinniiuumm ooddeerr kkeerraammiisscchheenn MMaatteerriiaalliieenn wwiiee SSiiOO _xx _xx ooddeerr AAll ^(O _y are coated This improves in particular their gas barrier properties..

Due to the surprising combination of excellent properties, the film according to the invention is outstandingly suitable for a large number of different applications, for example for interior cladding, for trade fair construction and trade fair articles, as displays, for signs, for protective glazing of machines and vehicles, in the lighting sector, in the store and shelf construction, as a promotional item, laminating medium, for thermal applications of all kinds, as packaging film for sensitive and effective advertising products. Due to the good UV stability, the film is also suitable for outdoor applications, e.g. B. for greenhouses, in the advertising sector, roofing, external cladding, covers, applications in the construction sector and illuminated advertising profiles.

The individual embodiments are measured in the following exemplary embodiments

Properties according to the following standards or procedures.

measurement methods

DEG content PEG content / IPA content

The DEG / PEG / I PA content is determined by gas chromatography after saponification in methanolic KOH and neutralization with aqueous HCl.

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

light transmission

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

The light transmission is measured with the measuring device "® Hazegard plus" according to ASTM D 1003.

Haze Haze is the percentage of transmitted light that deviates from the incident light beam by an average of more than 2.5 °. The image sharpness is determined at an angle of less than 2.5 °. The haze is measured using the "Hazegard plus" measuring device in accordance with ASTM D 1003.

surface defects

The surface defects are determined visually.

SV (DCE), IV (DCE)

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

The intrinsic viscosity (IV) is calculated as follows from the standard viscosity (SV)

IV (DCE) = 6.67 ^• 10 ^"4 SV (DCE) + 0.18

Weathering, UV stability

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

Atlas Ci 65 Weather Ometer test device

Test conditions ISO 4892, i.e. H. artificial weathering

Irradiation time 1000 hours on the non-vaporized 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 UV light, then 18 minutes UV light with water spraying of the samples, then again 102 minutes UV light etc. yellowness

The yellowness index (YID) is the deviation from the colorlessness in the "yellow" direction and is measured in accordance with DIN 6167. Yellowness indexes (YID) of <5 are not visually visible.

Examples

The following examples and comparative examples are each transparent films of different thicknesses, which are produced on the extrusion line described.

All films were weathered according to the test specification ISO 4892 for 1000 hours with the Atlas Ci 65 Weather Ometer from Atlas and then checked for discoloration, surface defects, haze and gloss.

Example 1 There is prepared a 150 .mu.m thick, red transparent colored film comprising, as main constituent, polyethylene terephthalate, 0.2 wt .-% Sylobloc ^®, 1, 0 wt .-% of the UV stabilizer 2- (4,6-diphenyl 1, 3,5-triazin-2-yl) -5- (hexyl) oxyphenol (Tinuvin ^® 1577 from Ciba-Geigy) and 1, 5 wt .-% of the soluble dye Solvent Red Cl 138, an anthraquinone derivative of the Fa. BASF AG ( ^® Thermoplastrot G) contains.

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

For the purpose of homogeneous distribution, 0.2% by weight of Sylobloc, 1.5% by weight of C.I. Solventrot 138 and 1, 0 wt .-% of the UV stabilizer incorporated into the polyethylene terephthalate.

The polyethylene terephthalate from which the transparently colored film is made has a standard viscosity SV (DCE) of 810, which corresponds to an intrinsic viscosity IV (DCE) of 0.658 dl / g. The amorphous, transparently colored, UV-stabilized PET film produced has the following property profile:

Thickness 150 μm

Surface gloss 1st page 155

( ^' unstructured side, measuring angle 20 °) 2. Page 150

Light transmission (420 - 800 nm) 89%

Turbidity 4.0%

Surface defects per m ² none

Yellowness index (YID) 3.1

Color homogeneous, red transparent

Absoφtion of UV light all wavelengths <380 nm

Example 2

Analogously to Example 1, a transparently colored film is produced, the UV stabilizer being 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) -oxyphenol (Tinuvin 1577) and Dye Cl Solventrot 138 is metered in in the form of a masterbatch. The masterbatch (100% by weight) consists of 5% by weight of Tinuvin 1577 as an active ingredient, 15.0% by weight of the dye C.I. Solventrot 138 and the polyethylene terephthalate from Example 1 together.

Before the extrusion, 90% by weight of the polyethylene terephthalate from Example 1 with 10% by weight of the masterbatch are dried at 170 ° C. for 5 hours. The extrusion and film production is carried out analogously to Example 1.

The transparent, colored, UV-stable PET film produced has the following property profile:

Thickness 150 μm

Surface gloss 1st page 160

(unstructured side, measuring angle 20 °) 2nd side 155 Light transmission (420 - 800 nm) 91%

Turbidity 3.8%

No surface defects

(Specks, orange peel, blisters, etc.)

Yellowness Index (YID) 3.4

Color homogeneous, red transparent

Absorption of UV light all wavelengths <380 nm

Example 3

Analogously to Example 2, a transparently colored 350 μm thick film is produced. The amorphous PET film produced has the following property profile:

Thickness 350 μm

Surface gloss 1st page 149

(unstructured side, measuring angle 20 °) 2nd side 1 142

Light transmission (420 - 800 nm) 85.1%

Turbidity 5.1%

Surface defects per m ² none

(Specks, orange peel, blisters, etc.)

Yellowness Index (YID) 4.5

Coloring homogeneous

Absorption of UV light all week

Example 4

According to co-extrusion technology, a 150 μm thick multilayer PET film with the layer sequence ABA is produced, where B represents the core layer and A the cover layers. The core layer B is 146 μm thick and the two outer layers that cover the core layer are each 2 μm thick. The polyethylene terephthalate used for core layer B is identical to that from example 2, but does not contain any sylobloc. The polyethylene terephthalate of the outer layers A is identical to the polyethylene terephthalate from Example 2, ie the outer layer raw material is equipped with 0.2% by weight of Sylobloc.

Analogously to Example 2, the 5.0% by weight of Tinuvin 1577 and 15.0% by weight of C.I. Solventrot 138 masterbatch used, but only 20 wt .-% of the masterbatch are added to the 2 μm thick cover layers using the masterbatch technology.

The transparently colored, multilayer PET film that is UV-stabilized in the outer layers has the following property profile:

Layer structure A-B-A

Overall thickness 150 μm

Surface gloss on page 164

(unstructured side, measuring angle 20 °)

2nd side (coated) 162

Light transmission mission 92.2%

Turbidity 2.2%

No surface defects

(Specks, orange peel, blisters, etc.)

Yellowness index (YID) 2.9

Coloring homogeneous

Absorption of UV light all week

Example 5

Example 4 is repeated. A cover layer A is coated with ethyl vinyl alcohol, the thickness of the coating being 1000 nm. The amorphous, transparently colored, UV-stabilized, thermoformable multilayer barrier film has the following property profile:

Overall thickness 150 μm

Surface gloss 1st side (measuring angle 20 °) 158

2nd side (coated) 124

Light transmission 85%

Turbidity 5.1%

No surface defects

(Specks, orange peel, blisters, etc.)

Color homogeneous, red transparent

Absorption of UV light all wavelengths <380 nm

Oxygen barrier <5 cm ³ / (m ^{2 ■} 24h ^■ bar) at 23 ° C

The examples according to the invention show that the optical properties of the films meet the high requirements, while at the same time the UV stability is significantly increased. The films from Examples 1 to 5 completely absorb the UV light in the wavelength range up to 380 or 390 nm and after 1000 hours of weathering with the Atlas Cl 65 Weather Ometer show no embrittlement, no noticeable loss of gloss and no change in the transparent coloration in the direction of yellow ,

thermoformability

The films from Examples 1 to 5 can be thermoformed into molded articles on commercial deep-drawing machines, for example from Illig / Heilbronn, without predrying. The detailed rendering of the deep-drawn moldings is excellent with a homogeneous surface. The films can be processed economically on continuously working thermoforming machines. Comparative Example 1

Analogously to Example 1, a 150 μm thick PET monofilm is produced. In contrast to Example 1, the film does not contain a UV stabilizer.

The unstabilized film produced has the following property profile:

Thickness 150 μm

Surface gloss 1st page 160

(Measuring angle 20 °) 2nd page 155

Light transmission 89%

Turbidity 4.6%

No surface defects

(Specks, orange peel, blisters, etc.)

Yellowness Index (YID) 2.7

Color homogeneous, red transparent

The film allows the short-wave radiation to pass through from 280 nm.

After weathering one side with Atlas Cl 65 Weather Ometer for 1000 hours, the film shows cracks and embrittlement on this surface. A precise property profile - especially the mechanical properties - can therefore no longer be measured. The film also shows a visually visible yellowing (YID)> 8.

Claims

claims

1. Amorphous, transparently colored, UV light absorbing, thermoformable film with a thickness in the range from 30 μm to 1000 μm, which contains a crystallizable thermoplastic as the main component, characterized in that it additionally contains at least one thermoplastic soluble UV stabilizer and at least contains a soluble dye.

2. Film according to claim 1, characterized in that the crystallizable thermoplastic made of polyethylene terephthalate, polybutylene terephthalate or polyethylene naphthalate or mixtures thereof, preferably polyethylene terephthalate with a diethylene glycol content of> 1.0% by weight and / or a polyethylene glycol content of> 1.0% by weight. -% and / or an isophthalic acid content of 3.0 to 10.0% by weight.

3. Film according to claim 1 or 2, characterized in that the crystallizable thermoplastic has a diethylene glycol content of preferably> 1.2% by weight, in particular> 1.3% by weight and / or a polyethylene glycol content of preferably> 1.2% by weight , in particular> 1.3% by weight and / or an isophthalic acid content of 3.0% by weight to 10.0% by weight.

4. Film according to claim 3, characterized in that the diethylene glycol and / or the polyethylene glycol content is in the range of 1.3% by weight to 5.0% by weight.

5. Film according to one or more of claims 1 to 4, characterized in that the concentration of the UV absorber in the range from 0.01% by weight to 5.0% by weight, preferably 0.1% by weight to 3% by weight and the concentration tration of the soluble dye in the range of 0.1 wt .-% to 20.0 wt .-%, based on the weight of the crystallizable polyester.

6. Film according to one or more of claims 1 to 5, characterized in that the UV absorbers as 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 and triazines, preferably 2-hydroxybenzotriazoles and triazines and in particular 2- (4,6-diphenyl-1, 3,5-triazin-2-yl) -5- (hexyl) oxyphenol or 2,2'- Methylene bis (6- (2H-benzotriazol-2-yl) -4- (1,1,2,2-tetramethylpropyl) phenol are present.

7. Film according to one or more of claims 1 to 6, characterized in that as dyes fat- and aromatic-soluble azo, benzopyrene and anthraquinone dyes, in particular C.I. Solvent Yellow 93, C.I. Solvent yellow 16,

Fluorol green gold, C.I. solvent red l, thermoplastic red BS, Sudan red BB, C.I. Solvent red 138, fluorol red GK and fluorol orange GK, C.I. Solvent blue 35, C.I. Solvent blue 15: 1 are included.

8. Film according to one or more of claims 1 to 7, characterized in that the regenerate is used.

9. A process for producing an amorphous, transparently colored, UV light absorbing, thermoformable film with a thickness in the range from 30 μm to 1000 μm, which contains a crystallizable thermoplastic as the main component, characterized in that a thermoplastic with at least one in the thermoplastic soluble UV absorber and at least one soluble dye is formed into a film by an extrusion process.

10. The method according to claim 9, characterized in that the UV absorber and the soluble dye are metered in at the thermoplastic raw material manufacturer or during film production in the extruder, an addition via the masterbatch technology being preferred.

11. The method according to claim 10, characterized in that the masterbatch in addition to the thermoplastic 2.0 to 50.0 wt .-%, preferably 5.0 to 30.0 wt .-% UV absorber and 1, 0 to 20, 0% by weight, preferably 1.5 to 15.0% by weight, of soluble dye, the sum of the constituents always being 100% by weight.

12. The method according to one or more of claims 9 to 11, characterized in that a crystallizable thermoplastic with a diethylene glycol content of> 1.0% by weight, preferably> 1.2% by weight, in particular> 1.3% by weight and / or a polyethylene glycol content of> 1.0% by weight, preferably

> 1.2% by weight, in particular> 1.3% by weight and / or an isophthalic acid content of 3% by weight to 10% by weight is used.

13. Use of the film according to one or more of claims 1 to 8 for use indoors and outdoors.

14. Use according to claim 13 in the interior for interior cladding, for trade fair construction and trade fair articles, as displays, for signs, for protective glazing of machines and vehicles, in the lighting sector, in shop and shelf construction, as promotional items, laminating medium, for thermal applications of all kinds , as packaging film for sensitive and effective advertising products and outdoors for greenhouses, in the advertising sector, roofing, external cladding, covers in the construction sector and illuminated advertising profiles.