DE10002177A1 - Amorphous, clear, thermoformable oriented film, used for interior and exterior purposes, e.g. cladding, advertising, display and lighting, based on crystallizable thermoplastics, contains ultraviolet absorber and gas barrier layer - Google Patents

Abstract

Amorphous, clear, ultraviolet (UV) light-absorbing, thermoformable oriented film with a thickness of 30-1000 mu m, which is based on a crystallizable thermoplastics material (I), contains UV absorber(s) soluble in (I) and has gas-barrier layer(s). An Independent claim is also included for the production of this film.

Description

The invention relates to an amorphous, transparent, UV-stabilized, thermoformable Barrier film of a crystallizable thermoplastic, whose thickness is in the range of 30 is up to 1000 microns. The film contains at least one barrier to gases and a Thermoplastically soluble UV absorber and is characterized by good optical Characteristics, by an economic Thermoformbarkeit and in particular by the Absorption of short-wave UV light in the wavelength range of less than 380 nm. The invention further relates to a process for the preparation of this film and their Use.

Transparent films are well known. The slides are usually oriented and have a crystallinity between 30 and 50%. These slides are crystalline or semi-crystalline structures. Furthermore, these films do not absorb that short-wave, aggressive UV light. From a wavelength of 280 nm, these films leave the UV light through.

Object of the present invention is the disadvantages of the prior Technology to avoid.

The invention therefore relates to an amorphous, transparent, UV-absorbing, thermoformable film having a thickness in the range of 30-1000 microns, as Main component contains a crystallizable thermoplastic, which thereby characterized in that they additionally comprise at least one UV-soluble thermoplastic Absorber contains and with at least one barrier or barrier layer against gases  and a process for their preparation and their use.

The film according to the invention has both good optical properties, has a Barrier against short-wave, aggressive UV light in the wavelength range of <380 nm and combines in combination a high UV stability with a barrier to oxygen and gases.

The good optical properties include, for example, a high light transmission, a low haze and a high surface gloss.

The film is also economically thermoformable, i. H. it settles on commercial Thermoforming machines without uneconomical pre-drying to complex and large-scale Deep-draw or thermoform moldings.

High UV stability means that the film and the moldings produced from it extremely little damage by sunlight or other UV radiation, so that they are suitable for outdoor and critical indoor applications. You should join perennial outdoor use does not yellow and no cracks or embrittlement of Show surface.

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

The good barrier effect against gases means that the oxygen permeability is <10 cm ³ / (m ² .24 h.bar).

The transparent film according to the invention contains a main component  crystallizable thermoplastics. Suitable crystallizable or semi-crystalline Thermoplastics are, for example, polyethylene terephthalate, polybutylene terephthalate, Polyethylene naphthalate, with polyethylene terephthalate (PET) being preferred.

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

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

The thermoplastic is z. B. in that the diethylene glycol content (DEG Content) and / or polyethylene glycol content (PEG content) greater than or equal to 1.0% by weight, in particular greater than or equal to 1.2 wt .-% is. In a particularly preferred Embodiment is the DEG content and / or PEG content in the range of 1.3 wt .-% to 5% by weight. He may additionally or instead of DEG and / or PEG also Isophthalic acid (IPA) in a concentration of 3 wt .-% to 10 wt .-%.

It was more than surprising that the slides were compared to the Standard Thermoplastics higher diethylene glycol content and / or polyethylene glycol content and / or IPA content economically thermoforming on commercially available thermoforming equipment and provide excellent detail reproduction.

Under amorphous film in the context of the present invention, such films although the crystallizable thermoplastic has a crystallinity of between 30% and and 65%, are not crystalline. Not crystalline, d. H. essentially amorphous means that the degree of crystallinity is generally below 5%, preferably below 2%, especially at 0%. Such a film is essentially in the unoriented  Condition before.

The film according to the invention may be both single-layered and multi-layered. The transparent film can also be used with various copolyesters or adhesion promoters be coated. The amorphous film contains for the purpose of economical production for Foils conventional antiblocking and lubricants.

The film according to the invention contains at least one UV stabilizer as Light stabilizer, wherein 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 crystallizable thermoplastic.

Light, in particular the ultraviolet portion of solar radiation, d. H. the Wavelength range of 280 to 400 nm, induces degradation of thermoplastics, as a result, not only the visual appearance due to color change or yellowing changes, but also the mechanical-physical properties be negatively affected.

The inhibition of these photooxidative degradation processes is of considerable technical and economic importance, otherwise the possible applications of numerous Thermoplastics are drastically limited.

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

In the presence of oxygen, chain scissions become major, but none  Crosslinks observed. Carbon monoxide, carbon dioxide and carboxylic acids represent the quantitatively predominant Photooxidationsprodukte dar. In addition to the direct photolysis The ester groups still have to be considered oxidation reactions, the via peroxide radicals also result in the formation of carbon dioxide.

Photooxidation of polyethylene terephthalates may also be via hydrogen abstraction in α-position of the ester groups to hydroperoxides and their decomposition products and lead to associated chain cleavage (H.Day, D.M. Wiles: J. Appl. Polym. Sci 16, 1972, page 203).

UV stabilizers or UV absorbers as light stabilizers are chemical compounds, which interfere with the physical and chemical processes of light-induced degradation can. Soot and other pigments can partially cause a sunscreen. These However, substances are unsuitable for transparent films, as they discolor or Change the color. For transparent, matt films are only organic and organometallic compounds suitable for the thermoplastic to be stabilized give no or only an extremely small color or color change, d. H. the one in the Thermoplastics are soluble.

For the purposes of the present invention, UV stabilizers are suitable as light stabilizers UV stabilizers containing at least 70%, preferably 80%, more preferably 90%, of UV light in the wavelength range of 180 nm to 380 nm, preferably 280 to Absorb 350 nm. These are particularly suitable if they are in the temperature range from 260 to 300 ° C are thermally stable, d. H. do not decompose and not to Outgassing lead. 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 anilides, Hydroxybenzoic acid esters, sterically hindered amines and triazines, where the 2-  Hydroxybenzotriazole and the triazines are preferred.

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

or 0.01% to 5.0% by weight of 2,2-methylenebis (6- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) - 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 be used with other UV stabilizers, the total concentration of Light stabilizer preferably between 0.01 wt .-% and 5.0 wt .-%, based on the Weight of crystallizable polyethylene terephthalate, lies.

It is quite surprising that the use of the above UV stabilizers in Slides to the desired result. When trying to get some UV To achieve stability via an antioxidant, the film quickly turns yellow after weathering.

If commercially available UV stabilizers are used which absorb the UV light and thus generally provide protection, it is found that

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

At these high concentrations, the film already has a yellow after production Appearance on, with yellow value differences (YID) around 25.

Therefore, it was more than surprising that even with low concentrations of the UV stabilizer according to the invention an excellent UV protection was achieved. Very surprising was that with this excellent UV protection

• The yellowness of the film compared to a non-stabilized film in the frame the measurement accuracy does not change,
• - no outgassing, no nozzle deposits set, causing the film a has excellent appearance and excellent profile and excellent Flatness has,  
• - The UV-stabilized film is characterized by excellent running safety, making them safe to process and stable on high speed film lines can be produced.

This makes the film economically viable.

It was also very surprising that the film was the aggressive, short - wave light in the Wavelength range up to 380 nm, preferably absorbed to 360 nm, d. H. Not pass through.

Furthermore, it is very surprising that the regenerated material can also be used again without negatively influence the yellow value of the film.

The film according to the invention contains at least one barrier layer which is applied by coating or vapor deposition. It consists of ethylene Vinyl alcohol copolymer, ethyl vinyl alcohol, polyvinyl alcohol or polyvinylidene dichloride, wherein ethylene-vinyl alcohol copolymer is preferred. In a preferred Embodiment, the thickness of the barrier layer is in the range of 10 nm to 8000 nm, in particular 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 h.bar). It is based on at least one ethylene-vinyl alcohol copolymer having an ethylene content of 15-60 mol% and a degree of saponification of at least 90 mol%, preferably greater than 96 mol%, in particular greater than 99 mol% , These copolymers include, for. 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 Patent 4,212,956.

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

The barrier layer based on ethylene-vinyl alcohol copolymers can be used to improve their thermoformability d. H. to reduce the crystallinity monomeric, oligomeric or contain polymeric substances. The amount added depends on the Compatibility, d. H. incorporability and miscibility with the main component as well the influence on the oxygen permeability.

Examples of such products are hydroxyl- and carbonyl-containing substances such as trimethylolpropane, neopentyl glycol and polyethylene glycols and in particular substances which in turn already have barrier properties, for. As polyvinyl alcohol or polyamides, mixtures of ethylene-vinyl alcohol copolymers and 10 to 50% by weight of polyvinyl alcohol having a degree of hydrolysis of <than 80, in particular greater than or equal to 88 mol%, and a viscosity of 0.4. 10 ^-2 to 4. 10 ^-2 in particular 0.4. 10 ^-2 to 1. 10 ^-2 Pa.s are particularly advantageous.

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

Under amorphous film in the context of the present invention, such films Although, the crystallizable thermoplastic has a crystallinity of 20% 65%, preferably from 30% to 50%, are not crystalline. Not crystalline, d. H. in the substantially amorphous, means that the degree of crystallinity is generally below 5%,  preferably less than 2%. Such a film is essentially in the unoriented Condition before.

The thermoforming process usually involves the steps of predrying, heating, molding, Cooling, demolding and tempering. In this process was surprisingly determined that the film according to the invention without prior predrying deep draw. This advantage compared to thermoformable polycarbonate and Polymethyl methacrylate films, where drying times of 10-15 hours - depending on Thickness - at temperatures of 100 ° C to 120 ° C are required, dramatically reduces the Cost of the forming process.

The surface gloss of the uncoated side, 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 74%, preferably more than 76% and the turbidity of the film measured according to ASTM D 1003 is less than 20%, preferably less than 15%, which is surprisingly good for the UV stability achieved.

The film according to the invention containing at least one UV stabilizer can be both be single-layered as well as multi-layered.

In the multilayer embodiment, the film is at least one core layer and at least one cover layer, wherein in particular a three-layered A-B layer A or A-B-C structure is preferred. In the multilayer case, one of the two Topcoats which may be corona treated with ethylene-vinyl alcohol copolymer, Ethyl vinyl alcohol, polyvinyl alcohol or polyvinylidene dichloride steamed. The Topcoats are with the usual anti-blocking agents for thermoplastic films and / or Lubricants are formulated.  

For this embodiment, it is essential that the thermoplastic of the core layer a similar standard viscosity possesses as the thermoplastic of the cover layer (s) to the Core layer adjacent (adjoining).

For the thermoforming process, the following parameters give the best results:

step Film according to the invention Pre-drying Not mandatory Temperature of the mold ° C 100-160 Heating time per 10 μm film thickness <5 sec per 10 μm thickness Film temperature at ° C 160-200 AL = L <deforming Possible draw factor 1.5-2.0 Detail reproduction Well Shrinkage (shrinkage)% <1.5

In a particular embodiment, the cover layers can also be made of a Polyethylene naphthalate - homopolymers or from a polyethylene terephthalate Polyethylene naphthalate - copolymers or compound exist.

In this embodiment, the thermoplastics of the cover layers also have one similar standard viscosity as the thermoplastic of the core layer.

In the multilayer embodiment, the UV stabilizer is preferably in or contain the cover layers. However, if required, the core layer may also be UV-cured. Stabilizers be equipped.

Unlike in the single-layered embodiment, the concentration of the  or the stabilizers on the weight of the thermoplastics in the with UV stabilizer (s) equipped layer.

Quite surprisingly, weathering tests according to the test specification ISO 4892 have The Atlas CI 65 Weather Ometer showed that in the case of a three-layer film is quite sufficient, the 0.5 μm to 10 μm thick outer layers with UV To equip stabilizers for improved UV stability.

As a result, the amorphous, produced by the known coextrusion technology, UV-stabilized, multi-layered films compared to the completely UV-stabilized ones Monofoils economically interesting, since significantly less UV stabilizer to a comparable UV stability is needed.

The film can also be at least one-sided with a scratch-resistant coating, with a Copolyester or be provided with a coupling agent.

Weathering tests have shown that the films according to the invention even at Weathering tests after extrapolated 5 to 7 years outdoor use in general no yellowing, no embrittlement, no gloss loss of the surface and none Have cracking on the surface.

During the production of the film, it was found that the film was process-safe produce. Furthermore, no outgassing of the UV stabilizer in Production process found what is essential to the invention, since in general the most UV stabilizers at extrusion temperatures above 260 C interfering, show unpleasant gas emissions and thus are unfit.

Furthermore, the film according to the invention without environmental impact and without  noticeable loss of mechanical properties easily recyclable, making them For example, it is suitable for use as a short-lived article.

Since the film in addition to the oxygen permeability and the short-wave UV light in Wavelength range from 260 nm to 380 nm, in particular absorbed up to 360 nm, offers the Foil a barrier against the aggressive short-wave light, the z. B. the dreaded Fat oxidation caused by food. Consequently, the invention is suitable Film outstanding as a packaging film for sensitive goods Vertical and horizontal packaging machines (vFFs and hFFs) Machinery).

Furthermore, the film according to the invention is suitable as a composite film, wherein the Composite of the film with ethylene-vinyl alcohol copolymers, ethyl vinyl alcohol, Polyvinyl alcohol or polyvinylidene dichloride coating and a second film. This second film can also be a UV-stable thermoplastic film, for. B. a polyester film or a standard polyester film or a polyolefin film.

The second film may be single-layered or multi-layered and may be like the first UV-stable Film amorphous, d. H. be unoriented and can have at least one sealant layer. The second film can with or without adhesive with the first invention UV-stable Barrier film be connected.

The thickness of this second film is preferably in the range of 30 to 500 microns.

The composite film is generally obtained by laminating or laminating of the two films with or without intermediate adhesive layer, by this passed between 30 ° C to 80 ° C tempered rollers.  

The two films can, for example, with or without adhesive layer by a Laminating be joined together. It is, for example, too possible, the second, transparent layer on the first, coated layer by in-line Apply coating (melt extrusion to an existing layer).

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

Particularly useful adhesives have proven that of thermoplastic Resins, such as cellulose esters and ethers, alkyl and acrylic esters, polyamides, Polyurethanes or polyesters, or thermosetting resins such as epoxy resins, Urea / formaldehyde, phenyl / formaldehyde or melamine / formaldehyde resins, or consist of synthetic rubbers.

As a solvent for the adhesive itself z. As hydrocarbons, such as ligroin and Toluene, esters, such as ethyl acetate, or ketones, such as acetone and methyl ethyl ketone.

The production of the film according to the invention can, for example, according to known Extrusion process in an extrusion line done.

According to the invention, the light stabilizer can already be used by the thermoplastic raw material manufacturer be dosed or metered in the film production in the extruder.

Preference is given to adding the light stabilizer via the masterbatch technology. in this connection the additive is first fully dispersed in a solid carrier material. When  Carrier materials are the thermoplastic itself, z. As the polyethylene terephthalate or Other polymers that are sufficiently compatible with the thermoplastic, in question. After metered addition to the thermoplastic for film production melt the Components of the masterbatch during extrusion and are so in the Thermoplastics solved.

The concentration of the UV absorber next to the thermoplastic in the masterbatch is 2.0 to 50.0 wt .-%, preferably 5.0 to 30.0 wt .-%, wherein the sum of the ingredients always 100 wt .-% is.

The DEG content and / or PEG content and / or IPA content of the thermoplastic are set at the raw material manufacturer during the polycondensation process.

Important in the case of masterbatch technology is that the grain size and the bulk density of the masterbatch is similar to the grain size and the bulk density of the thermoplastic, so that a homogeneous distribution and thus a homogeneous UV stabilization take place can.

The thermoplastic films can be prepared by the extrusion process from a Thermoplastic raw material with optionally further raw materials, the UV stabilizer and / or other conventional additives in the usual amount of from 0.1 to a maximum of 10% by weight both as monofilms and as multilayer, optionally coextruded films be made with the same or differently shaped surfaces, wherein For example, one surface is pigmented and the other surface is not a pigment contains. Likewise, one or both surfaces of the film may be prepared by known methods be provided with a conventional functional coating.

The polymers or raw material mixtures are an extruder or in multilayer  Sheets fed to multiple extruders. About existing foreign body or Impurities can be filtered out of the polymer melt prior to extrusion. The Melt (s) are then in a Monodüse or in a multilayer case in one Multilayer nozzle formed into flat melt films and in the multilayer case layered on top of each other. Subsequently, the monofilm or the multilayer film with Help a take-off roll and possibly other rollers, if necessary, too can be structured, peeled off and solidified as an amorphous film. Subsequently, will the cooled, amorphous film lined and wound up.

In the preferred extrusion process for producing the thermoplastic film according to the Invention, the molten thermoplastic material through a slot die extruded and largely amorphous, d. H. unoriented film on a chill roll quenched and wound up. Subsequently, at least one surface layer with ethylene-vinyl alcohol copolymers, ethyl vinyl alcohol, polyvinyl alcohol or Polyvinylidene dichloride coated.

The film may carry another coating, 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, i. H. during the Film production process, expediently after solidification. Especially preferred is the application of the "reverse gravure-roll coating" process, in which the Coatings can be applied very homogeneously in the mentioned layer thicknesses. The Coatings are preferably applied as a solution, suspension or dispersion, in particular as aqueous solution, suspensions or dispersions. The mentioned Coatings give the film surface an additional function, for example the film is thereby sealable, printable, metallizable, sterilizable, antistatic or improve z. B. the aroma barrier or allow adhesion to materials that otherwise would not adhere to the film surface (eg, photographic emulsion).  

Examples of substances / compositions which confer additional functionality are:
Acrylates, such as For example, WO 94/13476 describes ethylvinyl alcohols, PVDC, water glass (Na ₂ SiO ₄ ), hydrophilic polyesters (5-sodium sulfoisophthalic acid-containing PET / IPA polyesters as described, for example, in EP-A-144 878, US Pat. US-A-4,252,885 or EP-A-0 296 620, vinyl acetates as described, for example, in WO 94/13481, polyvinyl acetate, polyurethanes, alkali metal or alkaline earth metal salts of C ₁₀ -C ₁₈ fatty acid, butadiene copolymers with acrylonitrile or methyl methacrylate, methacrylic acid, acrylic acid or their esters.

The substances / compositions mentioned are as dilute solution, emulsion or Dispersion, preferably as an aqueous solution, emulsion or dispersion on one or applied both film surfaces and then volatilized the solvent. When the coatings are applied in-line, one usually suffices Temperature treatment after solidification to volatilize the solvent and to dry the coating. The dried coatings then have the mentioned desired layer thicknesses.

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

Due to the surprising combination of excellent properties is the Film according to the invention excellent for a variety of applications, For example, for interior trim, for trade fair construction and trade show products, as displays, for signs, for protective glazing of machinery and vehicles, im Lighting sector, in shop and shelf construction, as promotional items, laminating medium, for Thermo applications of all kinds, as packaging film for sensitive products.  

Due to the good UV stability, the film is also suitable for outdoor applications, z. For greenhouses, in the advertising sector, roofing, exterior cladding, Covers, applications in the construction sector and illuminated advertising profiles.

In the following embodiments, the measurement of the individual takes place Properties according to the following standards or procedures.

Measurement Method DEG content / PEG content / IPA content

The DEG / PEG / IPA content is determined by gas chromatography after solution of the thermoplastic Raw material in cresol determined.

surface gloss

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

light transmission

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

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

cloudiness

Haze is the percentage of transmitted light from the incident Light beam deviates on average by more than 2.5 °. The focus will be at an angle less than 2.5 ° determined.  

The haze is measured with the "Hazegard plus" measuring instrument according to ASTM D 1003.

surface defects

The surface defects are determined visually.

SV (DCE), IV (DCE)

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

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

IV (DCE) = 6.67.10 ^-4 SV (DCE) +0.118

Weathering, UV stability

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

Test device: Atlas Ci 65 Weather Ometer Test conditions: ISO 4892, d. H. artificial weathering Irradiation time: 1000 hours on the uncoated side irradiation: 0.5 W / m ² , 340 nm Temperature: 63 ° C Relative humidity: 50% Xenon lamp: inner and outer filter made of borosilicate Irradiation cycles: 102 minutes of UV light, then 18 minutes of UV light with water spraying of the samples, then again 102 minutes of UV light, etc.

oxygen barrier

The oxygen permeability is measured according to DIN 53380.

yellowness

The yellow value (YID) is the deviation from the colorlessness in the direction of "yellow" and becomes measured according to DIN 6167. Yellow values (YID) of <5 are not visually visible.

Examples

In the following examples and comparative examples are each transparent films of different thickness on the described extrusion line getting produced.

All films were tested according to the test specification ISO 4892 on the uncoated side 1000 Hours with the Atlas Ci 65 Weather Ometer of the company Atlas weathered and then for discoloration, surface defects, haze and gloss.

example 1

It is made a 150 micron thick, transparent film, the main component Polyethylene terephthalate (DEG content 1.5%), 0.3 wt .-% ®Sylobloc and 1.0 wt .-% of UV stabilizer 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) oxyphenol (®Tinuvin 1577 der Company Ciba-Geigy).

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

For the purpose of homogeneous distribution, 0.3% by weight of Sylobloc and 1.0% by weight of UV Stabilizer incorporated into the polyethylene terephthalate.  

The polyethylene terephthalate from which the transparent film is made has a Standard viscosity SV (DCE) of 810, giving an intrinsic viscosity IV (DCE) of 0.658 dl / g.

A surface layer is coated with ethylene-vinyl alcohol copolymer, wherein the Thickness of the coating is 1000 nm.

The produced PET film has the following property profile:

Thickness: 150 μm Surface gloss 1st side: 155 (Measuring angle 20 °) 2nd side (coated): 95 Thickness: 150 μm Surface gloss 1st side: 155 (Measuring angle 20 °) 2nd side (coated): 95 Light transmission (420-800 nm): 87% turbidity: 8.0% Surface defects per m ² : none Yellow value (YID): 3.1

After 1000 hours of weathering the uncoated side with Atlas Cl 65 Weather Ometer, the PET film shows the following characteristics:

Thickness: 150 μm Surface gloss 1st side: 145 (Measuring angle 20 °) 2nd side (coated): 95 Light transmission (420-800 nm): 86% turbidity: 8.5% Surface defects per m ² (cracks, embrittlement): none Yellow value (YID): 3.6

Example 2

Analogously to Example 1, a transparent film is produced, wherein the UV stabilizer 2- (4,6- Diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) -oxyphenol (Tinuvin 1577) in the form of a Masterbatches is added. The masterbatch is composed of 5% by weight Tinuvin 1577 as Active component and 95 wt .-% of polyethylene terephthalate from Example 1 together.

Before extrusion, 90% by weight of the polyethylene terephthalate from Example 1 with 10% by weight of the masterbatch dried at 170 ° C for 5 hours. The extrusion and Film production takes place analogously to Example 1.

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

Thickness: 150 μm Surface gloss 1st side: 160 (Measuring angle 20 °) 2nd side (coated): 90 Light transmission 86% turbidity: 8.8% Surface defects per m ² (specks, orange peel, blisters, etc.): none Yellow value (YID): 3.4

After 1,000 hours of weathering of the uncoated side as in Example 1, the PET film exhibits the following properties:

Thickness: 150 μm Surface gloss 1st side: 148 (Measuring angle 20 °) 2nd side (coated): 90 Light transmission 85% turbidity: 6.1% Surface defects per m ² (specks, orange peel, blisters, etc.): none Yellow value (YID): 4.3

Example 3

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

Thickness: 350 μm Surface gloss 1st side: 149 (Measuring angle 20 °) 2nd side (uncoated): 84 Light transmission 74.1% turbidity: 5.1% Surface defects per m ² (specks, orange peel, blisters, etc.): none Yellow value (YID): 4.5

After 1000 hours of weathering as in Example 1, the PET film has the following properties:

Thickness: 350 μm Surface gloss 1st side: 136 (Measuring angle 20 °) 2nd side (uncoated): 83 Light transmission 73.3% turbidity: 16.0% Surface defects per m ² (specks, orange peel, blisters, etc.): none Yellow value (YID): 5.4

Example 4

After the coextrusion technology is a 150 micron thick multilayer PET film with layer sequence A-B-A, where B is the core layer and A the cover layers represent. The core layer B is 148 μm thick and the two cover layers which cover the core layer, each 1 micron thick.

The polyethylene terephthalate used for the core layer B is identical to that of Example 2, but contains no Sylobloc. The polyethylene terephthalate of the outer layers A is identical to the polyethylene terephthalate of Example 2, d. H. the coverstock raw material is equipped with 0.3 wt .-% Sylobloc.

Analogously to Example 2, the 5 wt .-% Tinuvin 1577 masterbatch is used, but only the 1 micron thick outer layers 20 wt .-% of the masterbatch on the Masterbatch technology be dosed. A cover layer is analogous to Example 1 with Coated ethylene-vinyl alcohol copolymer.

The produced transparent, multi-layered UV-stabilized PET film has the following property profile:

Layer structure: A-B-A Total thickness: 150 μm Surface gloss 1st side: 164 (Measuring angle 20 °) 2nd side (coated): 90 Light transmission 90.2% turbidity: 3.1% Surface defects per m ² (specks, orange peel, blisters, etc.): none Yellow value (YID): 2.9

After 1000 hours of weathering as in Example 1, the multilayer film exhibits the following properties:

Layer structure: A-B-A Total thickness: 50 μm Surface gloss 1st side: 152 (Measuring angle 20 °) 2nd side (coated): 90.2 Light transmission 89.6% turbidity: 4.0% Surface defects per m ² (specks, orange peel, blisters, etc.): none Yellow value (YID): 3.0

The examples show that the optical properties of the films meet the high requirements, while at the same time the UV stability is substantially increased. The films of Examples 1 to 4 completely absorb the UV light in the wavelength range up to 380 nm and show an oxygen permeability of <5 cm ³ / (m ² .24h.bar) at 23 ° C.

The amorphous, UV-stabilized, with an ethylene-vinyl alcohol copolymer barrier layer provided films from Examples 1-4 can be commercially available Thermoforming machines from Illig / Heilbronn, without pre-drying to form bodies thermoforming. The detail reproduction of the deep-drawn moldings is at a homogeneous surface excellent.

Comparative Example 1

Analogously to Example 1, a 150 micron thick PET monofilm is produced. In contrast to Example 1, the film contains no UV stabilizer.  

The produced unstabilized, transparent film has the following property profile:

Thickness: 150 μm Surface gloss 1st side: 160 (Measuring angle 20 °) 2nd side (coated): 95 Light transmission (420-800 nm): 86% turbidity: 7.6% Surface defects per m ² (specks, orange peel, blisters, etc.): none Yellow value (YID): 2.7

The foil transmits the short-wave radiation already from 280 nm.

After 1000 hours weathering a page with Atlas CI 65 Weather Ometer, the Film on this surface cracks and embrittlement phenomena. A precise Property profile - especially the mechanical properties - therefore can not be measured more. In addition, the film shows a visually visible yellowing.

Claims (15)

1. Amorphous, transparent, UV light-absorbing, thermoformable film having a thickness in the range of 30-1000 microns, containing as the main component a crystallizable thermoplastic, characterized in that it additionally contains at least one thermoplastic-soluble UV absorber and with at least a barrier or barrier layer is provided against gases. 2. A film according to claim 1, characterized in that the crystallizable Thermoplastic polyethylene terephthalate, polybutylene terephthalate or Polyethylene naphthalate or mixtures thereof, preferably Polyethylene terephthalate, having a diethylene glycol content of ≧ 1.0% by weight and / or a polyethylene glycol content of ≧ 1.0 wt .-% and or one Isophthalic acid content of 3.0 to 10.0 wt .-%, consists. 3. A film according to claim 1 or 2, characterized in that the crystallizable Thermoplastic a diethylene glycol content of preferably ≧ 1.2 wt .-%, in particular ≧ 1.3 wt .-% and / or a polyethylene glycol content of preferably ≧ 1.2 wt .-%, in particular ≧ 1.3 wt .-% and / or an isophthalic acid content of 3.0 wt .-% to 10.0 wt .-% has. 4. A film according to claim 3, characterized in that the diethylene glycol and / or the polyethylene glycol content in the range of 1.3% by weight to 5.0% by weight lies. 5. Film according to one or more of claims 1 to 4, characterized  the concentration of the UV absorber is in the range from 0.01% by weight to 5.0% by weight preferably 0.1% by weight to 3% by weight, based on the weight of the crystallizable thermoplastics, lies. 6. film according to one or more of claims 1 to 5, characterized that they are UV absorbers 2-hydroxybenzophenones, 2-hydroxybenzotriazoles, organo-nickel compounds, salicylic acid esters, cinnamic acid ester derivatives, Resorcinol monobenzoates, oxalic acid anilides, hydroxybenzoic acid esters, steric hindered amines and / or triazines, preferably 2-hydroxybenzotriazoles and Triazines and especially 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) oxy-phenol or 2,2'-methylenebis (6- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) -phenol contains. 7. A film according to one or more of claims 1 to 6, characterized that the barrier layer is based on an ethylene-vinyl alcohol Copolymers, polyvinyl alcohol or polyvinylidene chloride, preferably one Ethylene-vinyl alcohol copolymers having an ethylene content of 15-60 mol% and a saponification degree of at least 90 mol%, preferably greater than 96 mol% %, in particular greater than 99 mol%. 8. A film according to claim 7, characterized in that it ethylene-propylene Vinyl alcohol copolymers and reaction products of ethylene-vinyl alcohol Copolymers with lower aldehydes or ketones according to DE-OS 29 31 035 or US PS 42 12 956 contains. 9. film according to one or more of claims 1 to 8, characterized that the regenerate is used.   10. Method for producing an amorphous, transparent, UV light absorbent, thermoformable thermoplastic film made of a crystallizable Thermoplastics with a thickness in the range of 30 microns to 1000 microns, thereby characterized in that a thermoplastic with at least one in the thermoplastic soluble UV absorber molded into a film by an extrusion process and subsequently with a barrier layer based on an ethylene-vinyl alcohol Copolymers is coated. 11. The method according to claim 10, characterized in that a crystallizable Thermoplastic with a diethylene glycol content of ≧ 1.0 wt .-%, preferably ≧ 1.2 wt .-%, in particular ≧ 1.3 wt .-% and / or a polyethylene glycol content of ≧ 1.0 wt .-%, preferably ≧ 1.2 wt .-%, in particular ≧ 1.3 wt .-% and / or an isophthalic acid content of 3 wt .-% to 10 wt .-% is used. 12. The method according to claim 11 or 12, characterized in that the UV Absorber at the thermoplastic raw material manufacturer or in the film production in the Extruder is dosed, with the addition of the masterbatch technology is preferred. 13. The method according to claim 12, characterized in that the Materbatch next 2.0 to 50.0 wt.%, preferably 5.0 to 30.0 wt. Absorber contains, wherein the sum of the components is always 100 wt .-%. 14. Use of the film according to one or more of claims 1 to 9 for the Indoor and outdoor use. 15. Use according to claim 14 indoors for interior trim, for Trade fair construction and trade fair products, as displays, for signs, for protective glazing from  Machines and vehicles, in the lighting sector, in shop and shelf construction, as Promotional products, laminating medium, for thermal applications of any kind, as Packaging film for sensitive and promotional products and im Exterior for greenhouses, in the advertising sector, canopies, Exterior cladding, coverings in the construction sector and illuminated advertising profiles.