WO1998005499A1 - Multilayered coloured plate made of a crystallising thermoplastic material, process for producing the same and its use - Google Patents

Abstract

An amorphous, coloured, multilayered plate with 1 to 20 mm thickness contains a crystallising thermoplastic material as its main component and at least one inorganic and/or organic pigment as dye in at least one of the layers. Other additives, such as UV stabilisers, antioxidants and soluble dyes may also be contained therein.

Description

 Multilayer, colored sheet made of a crystallizable thermoplastic, process for its production and use

The invention relates to an amorphous, colored, plate made of a crystallizable thermoplastic, the thickness of which is in the range from 1 to 20 mm. The invention further relates to a method for producing this plate and its use.

Multi-layer plates made of plastic materials are known per se.

Such plates made of branched polycarbonates are described in EP-A-0 247 480, EP-A-320632 and US Pat. No. 5,108,835.

DE-A-34 14 116 and US Pat. No. 4,600,632 disclose UV-stabilized polycarbonate moldings which are composed of polydiorganosiloxane-polycarbonate block copolymers.

Multilayer plastic plates are known from US Pat. No. 5,137,949, with layers of polydiorganosiloxane-polycarbonate block copolymers which contain UV absorbers. EP-A-0 416404 discloses UV-stabilized, branched polycarbonates made from special diphenols. It is mentioned that such polycarbonates can be used for the production of plates or multi-wall sheets.

All of these plates are made of polycarbonate, an amorphous thermoplastic that cannot be crystallized. Polycarbonate sheets have the disadvantage that they often show efflorescence in the form of white spots and surface coverings, especially in the UV-stabilized embodiment (cf. EP-A-0 649 724). According to EP-A-0 649 724, for example, UV absorber evaporation is strongly linked to the average molecular weight. Furthermore, these PC boards are easily flammable and therefore require the addition of flame retardants in order to be used for certain purposes such as for indoor applications. In the further processing of these sheets into molded parts, lengthy pre-drying times and relatively long processing times at high temperatures are required. In addition, degassing extruders must be used in the manufacture of plates for the purpose of moisture removal, as a result of which the additives added to the raw material can also be removed, in particular if low-molecular, volatile additives are used.

The applicant has already described single-layer, colored, amorphous plates with a thickness in the range from 1 to 20 mm, the main constituent of which is a crystallizable thermoplastic such as e.g. Contain polyethylene terephthalate and an organic and / or inorganic pigment as a colorant (German Patent Application Nos. 19519577.9, 19522116. 2,19528333.3). These plates can have a standard viscosity of 800-6000 and contain a UV stabilizer.

EP-A-0 471 528 describes a method for molding an article from a polyethylene terephthalate (PET) plate. The PET sheet is heat-treated on both sides in a deep-drawing mold in a temperature range between the glass transition temperature and the melting temperature. The molded PET sheet is taken out of the mold when the degree of crystallization of the molded PET sheet is in the range of 25 to 50%. The PET sheets disclosed in EP-A-0471 528 have a thickness of 1 to 10 mm. Since the deep-drawn molded article made from this PET sheet is semi-crystalline and therefore no longer transparent and the surface properties of the molded article are determined by the deep-drawing process, the temperatures and shapes given, it is immaterial which optical properties (e.g. gloss, haze and light transmission) ) have the PET sheets used. As a rule, the optical properties of these plates are poor and need to be optimized. These polyethylene terephthalate plates also have a single-layer structure and are not colored. US-A-3 496 143 describes the vacuum deep drawing of a 3 mm thick PET sheet, the crystallization of which is said to be in the range from 5 to 25%. The crystallinity of the deep-drawn molded body is greater than 25%. No demands are made on the optical properties of these PET sheets either. Since the crystallinity of the plates used is already between 5 and 25%, these plates are cloudy and opaque. These semi-crystalline PET sheets are also single-layer.

The Austrian patent specification No. 304 086 describes a process for the production of transparent moldings by the deep-drawing process, a PET plate or film with a degree of crystallinity below 5% being used as the starting material.

The plate or film used as the starting material has one layer and was produced from a PET with a crystallization temperature of at least 160 ° C. It follows from this relatively high crystallization temperature that this is not a PET homopolymer, but rather glycol-modified PET, or PET-G for short, which is a PET copolymer.

In contrast to pure PET, PET-G shows an extremely low tendency to crystallize due to the additional built-in glycol units and is usually in the amorphous state.

The object of the present invention is to provide a multilayer, amorphous, colored plate with a thickness of 1 mm to 20 mm, which is characterized by good mechanical and homogeneous optical properties.

Homogeneous optical properties include, for example, homogeneous light transmission with a high surface gloss.

The good mechanical properties include high impact strength and high breaking strength.

In addition, the plate of the invention should be recyclable, in particular without loss of mechanical properties, as well as difficult to burn, so that it can also be used for indoor applications and trade fair construction, for example.

This object is achieved by a multi-layer, colored, amorphous plate with a thickness of 1 to 20 mm, which contains at least one crystallizable thermoplastic as the main component, which is characterized in that the plate has at least one core layer and at least one cover layer, the standard viscosity of the crystallizable thermoplastic of the core layer is higher than the standard viscosity of the crystallizable thermoplastic of the top layer and that at least one layer contains at least one organic and / or inorganic pigment as colorant.

For the purposes of the present invention, amorphous plate is understood to mean plates which, although the crystallizable thermoplastic used preferably has a crystallinity of between 5 and 65%, are not crystalline. Not crystalline, i.e. essentially amorphous means that the degree of crystallinity is generally below 5%, preferably below 2% and particularly preferably 0% and that the plate has essentially no orientation.

According to the invention, crystallizable thermoplastic is understood to mean crystallizable homopolymers, crystallizable copolymers, crystallizable compounds, crystallizable recyclate and other variations of crystallizable thermoplastics.

Examples of suitable thermoplastics are polyalkylene terephthalates with C1 to C12 alkylene radicals, such as polyethylene terephthalate and polybutylene terephthalate, polyalkylene naphthalates with C1 to C12 alkylene radicals, such as polyethylene naphthalate and polybutylene naphthalate, crystallizable cycloolefin polymers and cycloolefin copolymers, the thermoplastic (or the thermoplastic) referred to as the base layer) and the thermoplastic or the thermoplastics for the cover layer (s) may be the same or different. Polyolefins have also proven suitable for the top layer.

Thermoplastics with a crystallite melting point T _m , measured with DSC (differential scanning calorimetry) with a heating rate of 10 ° C / min, from 220 ° C to 260 ° C, preferably from 230 ° C to 250 ° C, with a crystallization temperature range T _c between 75 ° C and 260 ° C, a glass transition temperature T _g between 65 ° C and 90 ° C and with a density, measured according to DIN 53479, of 1.30 to 1.45 g / cm ³ and a crystallinity between 5% and 65 % are preferred starting materials for the production of the plate, which are polymers for the core layer and the top layer. For the purposes of the invention, a thermoplastic with a cold (post) crystallization temperature T _CN of 120 to 158 ° C., in particular 130 to 158 ° C. , particularly preferred.

The bulk density, measured according to DIN 53466, is preferably between 0.75 kg / dm ³ and 1.0 kg / dm ³ , and particularly preferably between 0.80 kg / dm ³ and 0.90 kg / dm ³ .

The polydispersity of the thermoplastic ^ / M ,, measured by GPC is preferably between 1.5 and 6.0 and particularly preferably between 2.0 and 5.0.

A particularly preferred crystallizable thermoplastic for the core layer (s) or the cover layer (s) is polyethylene terephthalate. The polyethylene terephthalate preferably used according to the invention essentially consists of monomer units of the following formula

It is essential to the invention that the thermoplastic or the thermoplastics of the core layer (s) has a higher standard viscosity than the thermoplastic or the Thermoplastic of the top layer (s). The standard viscosities of the thermoplastics of different core and / or cover layers of a multilayer plate can be different.

The standard viscosity SV (DCE) of the crystallizable thermoplastic of the core layer or base layer, measured in dichloroacetic acid according to DIN 53728, is preferably between 800 and 5000 and particularly preferably between 1000 and 4500.

The standard viscosity SV (DCE) of the crystallizable thermoplastic of the top layer, measured in dichloroacetic acid according to DIN 53728, is preferably between 500 and 4500 and particularly preferably between 700 and 4000.

The intrinsic viscosity IV (DCE) can be calculated from the standard viscosity SV (DCE) as follows:

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

The amorphous, multilayer plate according to the invention also contains at least one organic and / or inorganic pigment. The pigment or a mixture of pigments can be added to one or more of the layers. The concentration of the colorant is preferably in the range from 0.1 to 30% by weight, based on the weight of the thermoplastic in the layer provided with pigment.

Organic and inorganic pigments suitable for the invention are described in the aforementioned German patent applications Nos. 195 195 77.9, 195 221 19.2 and 195 283 33.3. These applications are cited as belonging to the disclosure of the present application.

In terms of colorants, a distinction is made between dyes and pigments according to DIN 55944. Pigments are almost insoluble in the polymer under the respective processing conditions, while dyes are soluble (DIN 55949). The coloring effect of the pigments is caused by the particles themselves. The term pigment is generally linked to a particle size of 0.01 to 1.0 μm. According to DIN 53206, a distinction is made in the definition of pigment particles between primary particles, aggregates and agglomerates.

Because of their extremely small particle size, primary particles, which are usually obtained during production, have a pronounced tendency to aggregate. As a result, aggregates are formed from the primary particles by area-by-layer assembly, which therefore have smaller surfaces than the sum of the surface area of their primary particles. Agglomerates are formed by the stacking of primary particles and / or aggregates over corners and edges, the total surfaces of which differ only slightly from the sum of the individual areas. If one speaks - without further details - of pigment particle size, one refers to the aggregates as they exist essentially after the coloring.

In powdered pigments, the aggregates are always stored together to form agglomerates that have to be broken up during coloring, wetted by the plastic and distributed homogeneously. These simultaneous processes are called dispersion. In contrast, coloring with dyes is a solution process, as a result of which the dye is present in molecular solution.

In contrast to the inorganic pigments, there is no complete insolubility with individual organic pigments, especially not with simple pigments with low molecular weights.

Dyes are adequately described by their chemical structure. However, pigments of the same chemical composition can be produced and present in different crystal modifications. A typical example of this is the white pigment titanium dioxide, which can be in the rutile form and in the anatase form. In the case of pigments, an improvement in the properties of use can be achieved by coating, ie by post-treatment of the pigment particle surface, with organic or inorganic agents. This improvement lies in particular in facilitating the dispersion and increasing the resistance to light, weather and chemicals. Typical coating agents for pigments are, for example, fatty acids, fatty acid amides, siloxanes and aluminum oxides.

Suitable inorganic pigments are, for example, the white pigments titanium dioxide, zinc sulfide and tin sulfide, which can be coated organically and / or inorganically.

The titanium dioxide particles can consist of anatase or rutile, preferably predominantly rutile, which has a higher covering power than anatase. In a preferred embodiment, the titanium dioxide particles consist of at least 95% by weight of rutile. You can by a usual procedure, e.g. by the chloride or sulfate process. The average particle size is relatively small and is preferably in the range from 0.10 to 0.30 μm.

Titanium dioxide of the type described does not produce any vacuoles within the polymer matrix during plate production.

The titanium dioxide particles can have a coating of inorganic oxides, as is usually used as a coating for TiO ₂ white pigment in papers or paints to improve the lightfastness. As is well known, TiO ₂ is photoactive. When exposed to UV rays, free radicals form on the surface of the particles. These free radicals can migrate to the film-forming components of the paint, which leads to degradation reactions and yellowing. The particularly suitable oxides 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 can organic compounds with polar and non-polar groups contain. The organic compounds must be sufficiently thermostable in the manufacture of the plate by extrusion of the polymer melt. Polar groups are, for example, -OH, -OR, -COOX (X = R, H or Na, R = alkyl with 1 to 34 carbon atoms). Preferred organic compounds are alkanols and fatty acids with 8 to 30 carbon atoms in the alkyl group, in particular fatty acids and primary n-alkanols with 12 to 24 carbon atoms, and polydiorganosiloxanes and / or polyorganohydrogensiloxanes such as polydimethylsiloxane and polymethylhydrogensiloxane.

The coating on the titanium dioxide particles usually consists of 1 to 12, in particular 2 to 6 g of inorganic oxides and 0.5 to 3, in particular 0.7 to 1.5 g of organic compound, based on 100 g of titanium dioxide particles. The coating is applied to the particles in aqueous suspension. The inorganic oxides are made from water-soluble compounds, e.g. Alkali, in particular sodium aluminate, aluminum hydroxide, aluminum sulfate, aluminum nitrate, sodium silicate (water glass) or silica precipitated in the aqueous suspension.

Inorganic oxides such as Al ₂ O ₃ and SiO ₂ are also to be understood as the hydroxides or their various dewatering stages such as oxide hydrates, without knowing their exact composition and structure. After the glow and grinding in aqueous suspension, the oxide hydrates, for example of aluminum and / or silicon, are precipitated onto the Ti0 ₂ pigment, and the pigments are then washed and dried. This precipitation can thus take place directly in a suspension, as occurs in the manufacturing process after the annealing and the subsequent wet grinding. The oxides and / or oxide hydrates of the respective metals are precipitated 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 in the pH range between by adding aqueous ammonia solution or sodium hydroxide solution 5 and 9, preferably between 7 and 8.5, the oxide hydrate precipitates. Assuming a water glass or alkali aluminate solution, the pH of the TiO ₂ suspension presented should be in the strongly alkaline range (pH greater than 8). The precipitation then takes place through Addition of mineral acid such as sulfuric acid in the pH range from 5 to 8. After the precipitation of the metal oxides, the suspension is stirred for a further 15 minutes to about 2 hours, the precipitated layers aging. The coated product is separated from the aqueous dispersion and, after washing at elevated temperature, in particular at 70 to 110 ° C., is dried.

Typical inorganic black pigments are carbon black modifications, which can also be coated, carbon pigments that differ from the carbon black pigments in their higher ash content, and oxidic black pigments such as iron oxide black and copper, chromium, iron oxide mixtures (mixed phase pigments).

Suitable inorganic colored pigments are oxidic colored pigments, hydroxyl-containing pigments, sulfidic pigments and chromates.

Examples of colored oxide pigments are iron oxide red, titanium dioxide-nickel oxide-antimony oxide mixed-phase pigments, titanium dioxide-chromium oxide-antimony oxide mixed-phase pigments, mixtures of the oxides of iron, zinc and titanium, chromium oxide-iron oxide brown, spinels of the cobalt-aluminum-titanium-nickel-zinc oxide system and Mixed phase pigments based on other metal oxides.

Typical hydroxyl-containing pigments are, for example, oxide hydroxides of trivalent iron such as FeOOH.

Examples of sulfidic pigments are cadmium sulfide selenides, cadmium zinc sulfides, sodium aluminum silicate with sulfur bound in polysulfide form in the lattice.

Examples of chromates are the lead chromates, which can be monoclinic, rhombic and tetragonal in the crystal forms.

Like the white and black pigments, all colored pigments can be both uncoated and also inorganic and / or organically coated. The organic colored pigments are generally divided into azo pigments and so-called non-azo pigments.

The azo (-N = N -) group is characteristic of the azo pigments. Azo pigments can be monoazo pigments, diazo pigments, diazo condensation pigments, salts of azo color acids and mixtures of the azo pigments.

In special embodiments, the amorphous, multilayer plate can also contain mixtures of inorganic and / or organic pigments and additionally soluble dyes in the core layer and / or top layer.

The concentration of the soluble dye is preferably in the range from 0.01 to 20% by weight, particularly preferably in the range from 0.5 to 10% by weight, based on the weight of the crystallizable thermoplastic.

Of the soluble dyes, the fat and aromatic soluble dyes are particularly preferred. These are azo and anthraquinone dyes.

Soluble dyes suitable for the present invention are in the German

Patent applications nos. 195 195 78.7, 195221 20.6 and 195 283 34.1.

These applications belong to the disclosure content of the present by quotation

Registration.

The crystallizable thermoplastics used according to the invention can be obtained by customary processes known to the person skilled in the art.

In general, thermoplastics, such as those used according to the invention, can be obtained by polycondensation in the melt or by a two-stage process

Polycondensation can be obtained. The first step up to an average molecular weight - corresponding to an average intrinsic viscosity IV of about 0.5 to 0.7 - in the melt and the further condensation

Solid condensation carried out.

The polycondensation is usually carried out in the presence of known

Polycondensation catalysts or catalyst systems carried out. In the

Solid condensation, chips from the thermoplastic under reduced Pressurized or under protective gas at temperatures in the range of 180 to 320 ° C until the desired molecular weight is reached.

For example, the production of polyethylene terephthalate, which is particularly preferred according to the invention, is described in detail in a large number of patent applications, such as in JP-A-60-139 717, DE-C-2 429 087, DE-A-27 07 491, DE -A-23 19 089, DE-A-16 94461, JP-63-41 528, JP-62- 39621, DE-A-41 17 825, DE-A-42 26737, JP-60-141 715, DE -A-27 21 501 and US-A-5 296 586.

Polyethylene terephthalates with particularly high molecular weights can be e.g. by polycondensation of dicarboxylic acid diol precondensates (oligomers) at elevated temperature in a liquid heat transfer medium in the presence of conventional polycondensation catalysts and, if necessary, co-condensable modifiers if the liquid heat transfer medium is inert and free of aromatic components and a boiling point in the range from 200 to 320 ° C has, the weight ratio of dicarboxylic acid diol precondensate (oligomers) to liquid heat transfer medium is in the range from 20:80 to 80:20, and the polycondensation is carried out in the boiling reaction mixture in the presence of a dispersion stabilizer.

The multi-layer, colored, amorphous plate according to the invention can, if desired, also be equipped with suitable additives. Depending on requirements, these additives can be added individually or as a mixture to one or more layers of the plate, which can also be layers with colorant. Examples of suitable additives are UV stabilizers and antioxidants as described in German Patent Application No. 195 221 19.2 and the copending application by the same applicant, entitled 'Polyethylene terephthalate plate with improved hydrolysis stability'. These applications are cited as part of the disclosure content of the present application. As stated above, the multi-layer, colored, amorphous plate can additionally contain at least one UV stabilizer as light stabilizer in the top layer (s) and / or the core layer (s).

Light, especially the ultraviolet portion of solar radiation, i.e. the wavelength range from 280 to 400 nm initiate 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 the mechanical-physical properties are adversely affected.

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

A high UV stability means that the plate is not or only slightly damaged by sunlight or other UV radiation, so that the plate is suitable for outdoor applications and / or critical indoor applications and shows no or only slight yellowing even after several years of outdoor use.

For example, polyethylene terephthalates 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 acid are the predominant quantities of photo-oxidation 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 take place Hydrogen cleavage in the α-position of the ester groups leads to hydroperoxides and their decomposition products as well as to chain cleavages connected with them (H. Day, DM Wiles: J. Appl. Polym. Sei 16, 1972, page 203).

UV stabilizers, also called light stabilizers or UV absorbers, are chemical compounds that can intervene in the physical and chemical processes of light-induced degradation.

Certain pigments such as Soot can partially protect against light. However, these substances are unsuitable for the colored plates according to the invention, since they lead to discoloration or color change. For the amorphous plates according to the invention, only such UV stabilizers, e.g. from the class of organic and organometallic compounds used, which cause no or only an extremely small color or color change in the thermoplastic to be stabilized.

Examples of UV stabilizers suitable for the present invention are 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, 2-hydroxybenzotriazoles being preferred. Mixtures of several UV stabilizers can also be used.

The UV stabilizer is expediently present in one layer in a concentration of 0.01% by weight to 8% by weight, preferably from 0.01 to 5% by weight, based on the weight of the thermoplastic, in the layer with the stabilizer equipped layer, before.

However, if the UV stabilizer is added to a core layer, a concentration of 0.01% by weight to 1% by weight, based on the weight of the thermoplastic in the core layer provided with the stabilizer, is generally sufficient. According to the invention, several layers can be equipped with a UV stabilizer at the same time. In general, however, it is sufficient if the layer is on the UV radiation occurs.

The core layer (s) can be equipped in order to prevent UV radiation which occurs in the event of possible damage to the cover layer from affecting the underlying core layer.

In a particularly preferred embodiment, the colored, amorphous plate according to the invention contains, as the main constituent, a crystallizable polyethylene terephthalate for the core layer and cover layer and 0.01% to 8.0% by weight of 2- (4,6-diphenyl-1,3 , 5-triazin-2-yl) -5- (hexyl) oxyphenol or 0.01% by weight to 8.0% by weight of 2,2'-methylene-bis (6- (2H-benzotriazole- 2-yl) -4- (1, 1, 3,3-tetramethylbutyl) phenol in the top layer.

Of course, a mixture of these compounds and a mixture of at least one of these compounds with at least one other UV stabilizer can also be used.

The plate according to the invention can also be equipped with at least one antioxidant.

Antioxidants are chemical compounds that can delay the signs of oxidation and hydrolysis and the resulting aging.

Antioxidants suitable for the plate according to the invention can be divided as follows:

Additive group Substance class primary antioxidants sterically hindered phenols and / or secondary, aromatic amines secondary antioxidants phosphites and phosphonites, thioethers, carbondiimides, zinc dibutyl dithiocarbamate

Furthermore, mixtures of primary and secondary antioxidants and / or mixtures of secondary and / or primary antioxidants with UV Stabilizers are used. Surprisingly, it has been found that such mixtures show a synergistic effect.

In a preferred embodiment, the amorphous plate according to the invention contains a phosphite and / or a phosphonite and / or a carbodiimide as a hydrolysis and oxidation stabilizer.

Examples of antioxidants used according to the invention are 2 - [(2,4,8,10-tetrakis (1, 1-dimethylethyl) dibenzo [d, f] [1, 3.2] dioxaphosphepin-6-yl] oxy) -ethyethanamine and Tris (2,4-di-tert-butylphenyl) phosphite.

The antioxidant is usually present in a concentration of 0.01 to 6% by weight, based on the weight of the thermoplastic of the layer provided with it.

The thickness of the multilayer plate according to the invention varies between 1 mm and 20 mm, the thickness of the cover layer (s) depending on the plate thickness being between 10 μm and 1 mm. The cover layers preferably each have a thickness between 400 to 500 μm.

As already stated, the plate according to the invention can have a plurality of core and cover layers which are sandwiched one above the other. However, the plate can also consist of only one cover layer and one core layer.

According to the invention, a structure with two cover layers and a core layer lying between the cover layers is particularly preferred.

The individual cover and core layers can contain different or identical crystallizable thermoplastics as main components, as long as the thermoplastic of a core layer has a higher standard viscosity than the thermoplastics of the cover layers directly adjacent to this core layer. A layer can also consist of a mixture of crystallizable thermoplastics. If desired, the colored, amorphous, multilayered plate according to the invention, which optionally contains one or more additives, can be provided on one or more sides with a scratch-resistant surface.

As coating systems and materials for the scratch-resistant surface

(Coating) come in all systems and materials known to the expert

Question.

Suitable coating systems and materials are particularly in the

German Patent Application No. 196 255 34.1 of the applicant, to which reference is made in full for the present invention.

Some of the large number of possible coating systems and materials are mentioned below.

(1) US-A-4822828 discloses aqueous radiation-curable coating compositions which, each based on the weight of the dispersion, (A) from 50 to 85% of a silane with vinyl groups, (B) from 15 to 50% of a multifunctional Acrylates and optionally (C) 1 to 3% of a photoinitiator.

(2) Also known are inorganic / organic polymers, so-called Ormocere (Organically Modified Ceramics), which combine properties of ceramic materials and polymers. Ormocers are used in particular as hard and / or scratch-resistant coatings on polymethyl methacrylate (PMMA) and polycarbonate (PC). The hard coatings are bound on the basis of Al ₂ O ₃ , ZrO ₂ , TiO ₂ or SiO ₂ as network formers and epoxy or methacrylate groups with Si through ≡Si-Cs compounds.

(3) Coating agents for acrylic resin plastics and polycarbonate based on silicone resin in aqueous-organic solution, which have a particularly high storage stability, are e.g. in EP-A-0 073 362 and

EP-A-0 073 911. This technique uses the condensation products of partially hydrolyzed organosilicon compounds as Coating agents, especially for glass and especially for acrylic resin plastics and PC.

(4) Acrylic coatings such as e.g. the Uvecryl products from UCB Chemicals. One example is the Uvecryl 29203, which is hardened with UV light. This material consists of a mixture of urethane acrylate oligomers with monomers and additives. Ingredients are approximately 81% acrylate oligomers and 19% hexanediol diacrylate. These coatings are also described for PC and PMMA.

(5) The literature also describes CVD or PVD coating technologies using a polymerizing plasma and diamond-like coatings (thin-film technology, published by Dr. Hartmut Frey and Dr. Gerhard Kienel, VDI Verlag, Düsseldorf, 1987). These technologies are used here in particular for metals, PC and PMMA.

Other commercially available coatings are e.g. Peeraguard from Peerless, Clearlite and Filtalite from Charvo, coating types such as the UVHC series from GE Silicones, Vuegard such as the 900 series from TEC Electrical Components, from the Societe Francaise Hoechst Highlink OG series, PPZ® products sold by Siber Hegner (manufactured by Idemitsu) and coating materials from Vianova Resins, Toagoshi, Toshiba or Mitsubishi. These coatings are also described for PC and PMMA.

Coating methods known from the literature are e.g. Offset printing, pouring, dipping, flooding, spraying or spraying, knife coating or rolling.

Coatings applied by the described methods are then cured, for example by means of UV radiation and / or thermally. In the case of the coating processes, it can be advantageous to treat the surface to be coated with a primer, for example based on acrylate or acrylatex, before applying the coating. Other known methods are, for example:

CVD processes or vacuum plasma processes, e.g. Vacuum plasma polymerization, PVD processes, such as coating with electron beam evaporation, resistance-heated evaporator sources or coating by conventional processes in high vacuum, such as in a conventional metallization.

Literature on CVD and PVD is, for example: Modern coating processes by H.-D. Steffens and W. Brandl. DGM Information Society Verlag Oberursel. Other literature on coatings: Thin Film Technology by L. Maissei, R. Glang, McGraw-Hill, New York (1983).

Coating systems which are particularly suitable for the purposes of the present invention are systems (1), (2), (4) and (5), with coating system (4) being particularly preferred.

Suitable coating processes are e.g. also the casting, the spraying, the spraying, the immersion and the offset method, the spraying method being preferred for the coating system (4).

When coating the amorphous plates, curing can take place with UV radiation and / or at temperatures which preferably do not exceed 80 ° C., UV curing being preferred.

The coating according to system (4) has the advantage that there is no crystallization which could cause turbidity. Furthermore, the coating shows excellent adhesion, excellent optical properties, very good chemical resistance and does not impair the intrinsic color.

The thickness of the scratch-resistant coating is generally between 1 and 50 μm.

The amorphous plate according to the invention, which is a main component contains installable thermoplastics such as PET, has excellent mechanical and optical properties. Thus, when measuring the impact strength a _n according to Charpy (measured according to ISO 179/1 D), preferably no breakage occurs on the plate. In addition, the notched impact strength a _k according to Izod (measured according to ISO 180 / 1A) of the plate is preferably in the range from 2.0 to 8.0 kJ / m ² , particularly preferably in the range from 4.0 to 6.0 kJ / m ^2nd

The surface gloss, measured according to DIN 67530 (measuring angle 20 °), is preferably greater than 100 and the light transmission, measured according to ASTM D 1003, is preferably less than 60%.

Weathering tests have shown that the UV-stabilized plate according to the invention has no visible yellowing and no visible loss of gloss and no visible surface defects even after 5 to 7 years of outdoor use.

In addition, the plate according to the invention is flame-retardant and does not drip off with very little smoke, so that it is also particularly suitable for indoor applications and trade fair construction.

Furthermore, the plate according to the invention can be easily recycled without any environmental pollution and loss of mechanical properties, which is why it is suitable, for example, for the production of short-lived advertising signs or other promotional items.

In addition, an excellent and economical thermoforming behavior (thermoforming and vacuum forming behavior) was found completely unexpectedly. Surprisingly, in contrast to polycarbonate sheets, it is not necessary to predry the sheet according to the invention before thermoforming. Polycarbonate sheets, for example, have to be pre-dried at approx. 125 ° C for 3 to 50 hours, depending on the sheet thickness, before thermoforming.

In addition, the plate according to the invention can be obtained with very short thermoforming cycle times and at low temperatures during thermoforming. Because of these properties, moldings can be produced economically and with high productivity from the plate according to the invention on conventional thermoforming machines.

The multilayered, colored, amorphous plate according to the invention, optionally equipped with one or more additives, can be produced in an extrusion line, for example, by the coextrusion process known per se.

Coextrusion as such is known from the literature (see e.g. EP-110 221 and EP-110 238, to which express reference is made here).

An extruder for plasticizing and producing the core layer and an additional extruder per cover layer are connected to each coextruder adapter. The adapter is constructed in such a way that the melts forming the cover layers are adhered as thin layers to the melt of the core layer. The multilayer melt strand produced in this way is then shaped in the subsequently connected nozzle and calibrated, smoothed and cooled in the smoothing unit before the plate is cut to length.

The process for producing the plates according to the invention is explained in general below.

If necessary, the thermoplastic polymer can be dried before coextrusion.

The drying can expediently take place at temperatures in the range from 110 to

190 ° C over a period of 1 to 7 hours. The main dryer is connected to the main extruder and one dryer is connected to one coextruder per top layer.

The thermoplastic or the thermoplastics for the core layer (s) and the cover layer (s) are then melted in the main extruder and in the coextruders. Preferably the temperature of the melt is in the range of 230 to 330 ° C, the temperature of the melt can essentially be adjusted both by the temperature of the extruder and the residence time of the melt in the extruder.

If the polyethylene terephthalate used in the invention as a preferred thermoplastic, is usually 4 to 6 hours at 160 to 180 C ^β dried and the temperature of the melt is adjusted in the range of 250 to 320 ° C.

The colorant and, if appropriate, the additive, such as a UV stabilizer and / or an antioxidant, can be metered into the thermoplastic of the corresponding layer at the raw material manufacturer or metered into the extruder during plate production.

The addition of the colorant and the additives via the masterbatch technology or via the solid pigment preparation is particularly preferred. The colorant and possibly the additives are fully dispersed in a solid carrier material. Suitable carrier materials are certain resins, the thermoplastic itself or other polymers which are sufficiently compatible with the thermoplastic.

It is important that the grain size and bulk density of the masterbatch are similar to the grain size and bulk density of the thermoplastic, so that a homogeneous distribution and thus a homogeneous effect of the colorant and the additives, such as e.g. homogeneous coloring and UV and hydrolysis stabilization can take place.

As already stated above, the main extruder for producing the core layer and the coextruder (s) are connected to a coextruder adapter in such a way that the melts forming the outer layers are adhered to the melt of the core layer as thin layers. The multilayer melt strand thus produced is shaped in a connected nozzle. This nozzle is preferably a slot die. The multi-layer melt strand formed by a slot die is then calibrated by smoothing calender rolls, ie intensively cooled and smoothed. The calender rolls used can, for example, be arranged in an I, F, L or S shape.

The material can then be cooled on a roller conveyor, cut to the side, cut to length and stacked.

The thickness of the plate obtained is essentially determined by the take-off which is arranged at the end of the cooling zone, the cooling (smoothing) rolls coupled to it in terms of speed and the conveying speed of the extruder on the one hand and the distance between the rolls on the other hand.

Both single-screw and twin-screw extruders can be used as extruders.

The slot die preferably consists of the dismantled tool body, the lips and the control bar for flow regulation across the width. To do this, the control bar can be bent using tension and compression screws. The thickness is adjusted by adjusting the lips. It is important to ensure that the temperature of the multilayer melt strand and the lip is uniform, otherwise the melt strand will flow out to different thicknesses through the different flow paths.

The calibration tool, ie the smoothing calender, gives the melt strand the shape and dimensions. This is done by freezing below the glass transition temperature by cooling and smoothing. In this state, no more deformation should take place, as otherwise surface defects would occur due to the cooling. For this reason, the calender rolls are preferably driven together. The temperature of the calender rolls must be lower than the crystallite melting temperature in order to avoid sticking of the melt strand. The melt strand leaves the slot die preferably at a temperature of 240 to 300 ° C. The first Depending on the output and plate thickness, the smoothing-cooling roller has a temperature between 50 ° C and 80 ° C. The second, somewhat cooler roller cools the second or other surface.

In order to obtain a uniform thickness in the range of 1 to 20 mm with good optical properties, it is essential that the temperature of the first smooth roller is 50 to 80 ° C.

While the calibration device freezes the surfaces of the plate as smoothly as possible and cools the profile to such an extent that it is dimensionally stable, the post-cooling device lowers the temperature of the plate to almost room temperature. After-cooling can be done on a roller board.

The speed of the take-off should be exactly matched to the speed of the calender rolls in order to avoid defects and thickness fluctuations.

A separating saw as a cutting device, the side trimming, the stacking system and a control point can be located in the extrusion line for producing the plates according to the invention as additional devices. The side or edge trimming is advantageous because the thickness in the edge area can be uneven under certain circumstances. The thickness and appearance of the plate are measured at the control point.

Due to the surprising number of excellent properties, the colored, amorphous plate according to the invention is excellently suitable for a variety of different applications, for example for interior cladding, for trade fair construction and trade fair articles, as displays, for signs, in the lighting sector, in shop and shelf construction, as promotional articles, as Menu card stands, as basketball goal boards, as room dividers, as aquariums, as information boards, as brochure and newspaper stands as well as for outdoor applications such as greenhouses, canopies, exterior cladding, covers, for applications in the construction sector, illuminated advertising profiles, balcony cladding and roof hatches. The invention is explained in more detail below on the basis of exemplary embodiments, without being restricted thereby.

The individual properties are measured according to the following standards and procedures.

Measurement methods

Surface gloss:

The surface gloss is determined in accordance with DIN 67 530. The reflector value is measured as an optical parameter for the surface of a plate. Based on the standards ASTM-D 523-78 and ISO 2813, the angle of incidence was set at 20 °. A light beam hits the flat test surface at the set angle of incidence and is reflected or scattered by it. The light rays striking the photoelectronic receiver are displayed as a proportional electrical quantity. The measured value is dimensionless and must be specified together with the angle of incidence.

Whiteness

The degree of whiteness is determined using the electrical reflectance 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 measurement filter. A barium sulfate compact (DIN 5033, part 9) is used as the white standard.

Surface defects:

The surface defects are determined visually. Charpy impact strength a _n:

This size is determined according to ISO 179/1 D.

Impact strength a _k according to Izod:

The notched impact strength or strength a _k according to Izod is measured according to ISO 180 / 1A.

Density:

The density is determined according to DIN 53479.

SV (DCE), IV (DCE):

The standard viscosity SV (DCE) is measured based on DIN 53728 in dichloroacetic acid.

The intrinsic viscosity is calculated from the standard viscosity as follows

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

Thermal properties:

The thermal properties such as crystal melting point T _m , crystallization temperature range T _c , post- (cold) crystallization temperature T _CN and glass transition temperature T _g are measured by differential scanning calorimetry (DSC) at a heating rate of 10 ° C / min.

Molecular weight, polydispersity:

The molecular weights M _w and M _n and the resulting polydispersity MM _n are measured by means of gel permeation chromatography.

Weathering (both sides), 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, ie artificial weathering Irradiation time 1000 hours (per side)

Irradiation 0.5 W / m ² , 340 nm

Temperature 63 ° C

Relative humidity 50%

Xenon lamp inner and outer filter made of borosilicate

Irradiation cycles 102 minutes of UV light, then 18 minutes of UV light with water spraying the samples, then again

102 minutes of UV light, etc.

The following examples and comparative examples are each colored plates of different thicknesses which are produced on the extrusion line described.

Example 1 :

A 4 mm thick, multi-layer, colored, amorphous polyethylene terephthalate plate with the layer sequence A-B-A, is produced by the described coextrusion process, B representing the base layer and A the top layer. The base layer B is 3.5 mm thick and the two cover layers which cover the base layer are each 250 mm thick.

The polyethylene terephthalate used for the base layer B has the following properties:

SV (DCE) 1100

IV (DCE) 0.85 dl / g

Density 1.38 g / cm ³

Crystallinity 44%

Crystallite melting point T _m 245 ° C

Crystallization temperature range T _c 82 to 245 ° C

After (cold) crystal temperature range T _CN 152 ° C

Polydispersity MM _n 2.02

Glass transition temperature 82 ° C The main component of the base layer is the polyethylene terephthalate described and 8% by weight of titanium dioxide.

The titanium dioxide is of the rutile type and is coated with an inorganic coating made of Al ₂ O ₃ and with an organic coating made of polydimethylsilane. The titanium oxide has an average particle diameter of 0.2 μm.

The titanium dioxide is added in the form of a master batch. The masterbatch is composed of 40% by weight of the titanium dioxide described as the active ingredient and 60% by weight of the polyethylene terephthalate described as the carrier material.

The polyethylene terephthalate from which the outer layers are made has a standard viscosity SV (DCE) of 1010, which corresponds to an intrinsic viscosity IV (DCE) of 0.79 dl / g. The moisture content is <0.2% and the density (DIN 53479) is 1.41 g / cm ³ . The crystallinity is 59%, the crystallite melting point according to DSC measurements being 258 ° C. The crystallization temperature range T _c is between 83 ° C and 258 ° C, the post-crystallization temperature (also cold crystallization temperature) T _CN at 144 ° C. The polydispersity M ^ M ,, of the polyethylene terephthalate polymer is 2.14. The glass transition temperature is 83 ° C.

Before the coextrusion, 80% by weight of the polyethylene terephthalate for the base layer and 20% by weight of the masterbatch are mixed and dried for 5 hours at 170 ° C. in the main dryer which is connected to the main extruder.

The polyethylene terephthalate for the base or core layer and the masterbatch are melted in the main extruder and the polyethylene terephthalate for the cover layers is melted in the coextruders. The extrusion temperature of the main extruder for the core layer is 281 ° C. The extrusion temperatures of the two coextruders for the cover layers are 294 ° C. The main extruder and the two coextruders are connected to a coextruder adapter which is constructed in such a way that the melts forming the outer layers are adhered to the melt of the core layer as thin layers. The multilayer melt strand produced in this way is shaped in the connected slot die and smoothed on a smoothing calender, the rollers of which are arranged in an S shape, to form a three-layer, 4 mm thick plate.

The first calender roll has a temperature of 65 ° C and the subsequent rolls each have a temperature of 58 ° C. The speed of the trigger is 4.2 m / min.

After the after-cooling, the three-layer colored panel is lined with cut-off saws at the edges, cut to length and stacked.

The white colored, amorphous, three-layer PET sheet has the following property profile:

Layer structure A-B-A

Overall thickness 4 mm

Base layer thickness 3.5 mm

Thickness of the outer layers each 0.25 mm

Surface gloss 1st page 152

(Measuring angle 20 °) 2nd page 148

Light transmission 0%

Whiteness 118

Coloring white, homogeneous

No surface defects

(Specks, blisters, orange peel, etc.)

Charpy impact strength a _n no break

Notched impact strength a _k according to Izod 5.1 kJ / m ² Crystallinity 0%

Roller coverings after 2 hours of production none

Example 2:

A three-layer colored plate is produced analogously to Example 1, a polyethylene terephthalate having the following properties being used for the core layer:

SV (DCE) 2717

IV (DCE) 1.9 dl / g

Density 1.38 g / cm ³

Crystallinity 44%

Crystallite melting point T _m 245 ° C

Crystall I i sation temperature range T _c 82 to 245 ° C

Cold crystallization temperature T _CN 154 ^β C

M _w 175 640 g / mol _n 49 580 g / mol

Polydispersity MM _n 2.02

Glass transition temperature 82 ° C

The titanium dioxide masterbatch is composed of 40% by weight of the titanium dioxide described in Example 1 and 60% by weight of the polyethylene terephthalate of this example.

The extrusion temperature is 280 ° C. The first calender roll has a temperature of 56 ° C and the subsequent rolls have a temperature of 50 ° C. The speed of the take-off and the calender rolls is 2.9 m / min.

The three-layer PET sheet produced has the following properties:

Layer structure ABA total thickness 6 mm Base layer thickness 5.5 mm

Thickness of the outer layers each 0.25 mm

Surface gloss 1st page 149

(Measuring angle 20 °) 2nd page 143

Light transmission 0%

Whiteness 125

Coloring white, homogeneous

No surface defects

(Specks, blisters, orange peel, etc.)

Charpy impact strength a _n no break

Notched impact strength a _k according to Izod 5.2 kJ / m ²

Crystallinity 0%

Roller coverings after 2 hours of production none

Example 3:

Analogously to Example 1, a three-layer, white-colored PET sheet is produced. 50% by weight of the polyethylene terephthalate from Example 1 are mixed with 30% by weight of recyclate from the plates of Example 1 and 20% by weight of the titanium dioxide masterbatch and dried and coextruded as in Example 1.

The three-layer, colored PET sheet produced has the following properties:

Layer structure A-B-A

Overall thickness 4 mm

Base layer thickness 3.5 mm

Thickness of the outer layers each 0.25 mm

Surface gloss 1st page 150

(Measuring angle 20 °) 2nd page 144

Light transmission 0%

Whiteness 127

Coloring white, homogeneous

No surface defects

(Specks, blisters, orange peel, etc.) Charpy impact strength a _n no break

Notched impact strength a _k according to Izod 4.9 kJ / m ²

Crystallinity 0%

Roller coverings after 2 hours of production none

Example 4:

A three-layer PET panel is produced analogously to Example 1. The main component of the base layer is the polyethylene terephthalate described in Example 1 and 1.0% by weight of the titanium dioxide from Example 1. The titanium oxide is incorporated directly into the polyethylene terephthalate for the base layer at the raw material manufacturer.

The two top layers contain as a main component the polyethylene terephthalate of the top layers from Example 1 and 0.5% by weight of the titanium dioxide for the base layer. The titanium dioxide is metered in directly from the raw material manufacturer. Drying, coextrusion and plate production are carried out analogously to Example 1.

The three-layer PET sheet produced has the following properties:

Layer structure A-B-A

Overall thickness 4 mm

Base layer thickness 3.5 mm

Ti0 ₂ content in the base layer 1.0% by weight

Thickness of the outer layers each 0.25 mm

Ti0 ₂ content in the outer layers 0.5% by weight

Surface gloss 1st page 121

(Measuring angle 20 °) 2nd page 118

Light transmission 36%

Color opal, white

No surface defects

(Specks, blisters, orange peel, etc.)

Charpy impact strength a _n no break Notched impact strength a _k acc. To Izod 4.8 kJ / m ² crystallinity 0%

Example 5:

A three-layer plate is produced analogously to Example 2. The plate is not colored white but green. The main component of the base layer is the polyethylene terephthalate from Example 2 and 9% by weight of pigment green 17. Pigment green 17 is a chromium oxide (Cr ₂ 0 ₃ ) from BASF (C®Sicopal green 9996).

The chromium oxide is added in the form of a master batch. The masterbatch is composed of 45% by weight of chromium oxide and 55% by weight of the polyethylene terephthalate from Example 2.

The two top layers contain as a main component the polyethylene terephthalate from Example 2 and 2% by weight of chromium oxide, the chromium oxide being metered in directly from the raw material manufacturer.

Drying, coextrusion and plate production are carried out analogously to Example 2.

The three-layer PET sheet produced has the following properties:

Layer structure A-B-A

Overall thickness 6 mm

Base layer thickness 5.5 mm

Cr ₂ 0 ₃ content in the base layer 9% by weight

Thickness of the outer layers each 0.25 mm

Cr ₂ 0 ₃ content in the cover layers 2% by weight

Surface gloss 1st page 116

(Measuring angle 20 °) 2nd page 114

Light transmission 0%

Color green, homogeneous

No surface defects

(Specks, blisters, orange peel, etc.) Charpy impact strength a _n no break

Notched impact strength a _k according to Izod 5.3 kJ / m ²

Crystallinity 0%

Roller coverings after 2 hours of production none

Example 6:

Analogously to Example 2, a three-layer, white-colored, amorphous PET plate is produced.

The two top layers contain as a main component the polyethylene terephthalate from Example 2 and 2.5% by weight of the UV stabilizer 2- (4,6-diphenyl-1, 3,5-triazin-2-yl) -5- (hexyl) contains oxyphenol (®Tinuvin 1577 from Ciba Geigy). Tinuvin 1577 has a melting point of 149 ° C and is thermally stable up to approx. 330 ° C.

2.5% by weight of the UV stabilizer is incorporated directly into the polyethylene terephthalate at the raw material manufacturer.

The drying, coextrusion and process parameters are chosen as in Example 2.

The three-layer PET sheet produced has the following properties:

Layer structure A-B-A

Overall thickness 6 mm

Base layer thickness 5.5 mm

Thickness of the outer layers each 0.25 mm

Surface gloss 1st page 138

(Measuring angle 20 °) 2nd page 134

Light transmission 0%

Whiteness white, homogeneous

No surface defects

(Specks, blisters, orange peel, etc.)

Charpy impact strength a _n no break Notched impact strength a _k according to Izod 5.1 kJ / m ²

Crystallinity 0%

Roller coverings after 2 hours of production none

After 1000 hours of weathering per side with the Atlas Ci 65 Weather Ometer, the PET plate shows the following properties:

Surface gloss 1st page 126

(Measuring angle 20 °) 2nd page 125

Light transmission 0%

Whiteness 120

Coloring white, homogeneous

No surface defects

(Specks, blisters, orange peel, etc.)

Charpy impact strength a _n no break

Notched impact strength a _k according to Izod 4.6 kJ / m ²

Crystallinity 0%

Example 7:

A three-layer plate is produced analogously to Example 1.

The cover layers contain 3.5% by weight of the UV stabilizer 2,2'-methylene-bis (6-

(2H-Benzotriazol-2-yl) 4- (1,1,3,3-tetramethylbutyl) phenol (®Tinuvin 360 from the company

Ciba Geigy), based on the weight of the top layer.

Tinuvin 360 has a melting point of 195 ° C and is thermally stable up to approx. 250 ° C.

As in Example 6, 3.5% by weight of the UV stabilizer is incorporated directly into the polyethylene terephthalate at the raw material manufacturer.

The three-layer PET sheet produced has the following properties: Layer structure ABA

Overall thickness 4 mm

Base layer thickness 3.5 mm

Thickness of the outer layers each 0.25 mm

Surface gloss 1st page 146

(Measuring angle 20 °) 2nd page 142

Light transmission 0%

Whiteness 116

Coloring white, homogeneous

No surface defects

(Specks, blisters, orange peel, etc.)

Charpy impact strength a _n no break

Notched impact strength a _k according to Izod 4.9 kJ / m ²

Crystallinity 0%

After 1000 hours of weathering per side with the Atlas Ci 65 Weather Ometer, the PET plate shows the following properties:

Surface gloss 1st page 138

(Measuring angle 20 °) 2nd page 134

Light transmission 0%

Whiteness 113

Coloring white, homogeneous

No surface defects

(Specks, blisters, orange peel, etc.)

Charpy impact strength a _n no break

Notched impact strength a _k according to Izod 4.6 kJ / m ²

Crystallinity 0% Comparative example

A colored plate is produced as in Example 1. The polyethylene terephthalate used for the core layer has a standard viscosity SV (DCE) of 760, which corresponds to an intrinsic viscosity IV (DCE) of 0.62 dl / g. The other properties are identical to the properties of the polyethylene terephthalate from Example 1 within the scope of the measurement accuracy. The titanium dioxide masterbatch, the outer layers, the process parameters and the temperature are chosen as in Example 1. Due to the low viscosity, plate production is not possible. The melt stability is insufficient. The emerging melt strand shows a multitude of flow flows and inhomogeneities.

Claims

claims 1. Multilayer, colored, amorphous plate with a thickness in the range from 1 to 20 mm, which contains a crystallizable thermoplastic as the main component, characterized in that it has a multilayer structure comprising at least one core layer and at least one top layer, the standard viscosity of the in the core layer containing thermoplastics is greater than the standard viscosity of the thermoplastic contained in the cover layer and wherein at least one layer of the plate contains at least one colorant selected from organic and inorganic pigments. 2. The plate of claim 1, wherein the standard viscosity of the thermoplastic of the at least one core layer is in the range from 800 to 5000 and that of the thermoplastic of the at least one cover layer is in the range from 500 to 4500. 3. Plate according to claim 1 or 2, wherein the plate has two cover layers and a core layer lying between the cover layers. 4. Plate according to one of the preceding claims, wherein the concentration of the pigment is in the range from 0.5 to 30% by weight, based on the weight of the crystallizable thermoplastic of the layer provided therewith. 5. Plate according to one of the preceding claims, wherein the plate additionally contains a soluble dye. 6. Plate according to one of the preceding claims, wherein at least one of the core and / or cover layer (s) is equipped with at least one UV stabilizer. 7. Plate according to claim 6, wherein the concentration of the UV stabilizer in the at least one layer is 0.01 to 8 wt .-%, based on the weight of the thermoplastic of the layer containing the UV stabilizer. 8. Plate according to claim 6 or 7, wherein the concentration of the UV stabilizer in the at least one core layer is 0.01 to 1 wt .-%, based on the weight of the thermoplastic of the core layer containing the UV stabilizer. 9. Plate according to one of claims 6 to 8, wherein the UV stabilizer is selected from 2-hydroxybenzotriazoles, triazines and mixtures thereof. 10. Plate according to claim 9, wherein the UV stabilizer is selected from 2- (4,6-diphenyl-1, 3,5-triazin-2-yl) -5- (hexyl) oxyphenol and 2,2'-methylene -bis (6- (2H-benzotriazol-2-yl) -4- (1, 1, 3,3-tetramethylbutyl) phenol. 11. Plate according to one of the preceding claims, wherein at least one of the core and / or outer layers is equipped with at least one antioxidant. 12. The plate of claim 11, wherein the antioxidant is present in a concentration of 0.1 to 6% by weight, based on the weight of the thermoplastic of the layer provided with it. 13. Plate according to claim 11 or 12, wherein the at least one antioxidant is selected from sterically hindered phenols, secondary, aromatic amines, phosphites, phosphonites, thioethers, carbondiimides and zinc dibutyldithiocarbamate. 14. The plate of claim 13, wherein the antioxidant 2- [2,4,8,10-tetrakis (1,1-dimethylethyl) dibenzo [d, f] [1,2,2] dioxaphosphepin-6-yl] oxy) -ethyl] ethanamine and / or tris (2,4-di-tert-butylphenyl) phosphite. 15. Plate according to one of the preceding claims, wherein the crystallizable thermoplastic for the core layer is selected from polyalkylene terephthalate with C1 to C12 alkylene, polyalkylene naphthalate with C1 to C12 alkylene, a cycloolefin polymer and a cycloolefin copolymer. 16. Plate according to one of the preceding claims, wherein the crystallizable thermoplastic for the cover layer is selected from polyalkylene terephthalate with C1 to C12 alkylene radical, polyalkylene naphthalate with C1 to C12 alkylene radical, a polyolefin, a cycloolefin polymer and a cycloolefin copolymer. 17. Plate according to claim 15 or 16, wherein the alkylene radical is ethylene or butylene. 18. Plate according to one of the preceding claims, wherein the thermoplastic for the core and cover layer is the same. 19. Plate according to one of claims 15 to 18, wherein the thermoplastic is polyethylene terephthalate. 20. Plate according to one of claims 15 to 19, wherein the thermoplastic contains a recyclate of the thermoplastic. 21. Plate according to one of the preceding claims, wherein the thermoplastic has a crystallite melting point, measured by DSC with a heating rate of 10 ° C / min., In the range from 220 to 280 ^β C. 22. Plate according to one of the preceding claims, wherein the thermoplastic has a crystallization temperature, measured by DSC with a heating rate of 10 ° C / min., In the range from 75 to 280 ° C. 23. Plate according to one of the preceding claims, wherein the thermoplastic used has a crystallinity which is in the range from 5 to 65. 24. Plate according to one of the preceding claims, wherein the thermoplastic used has a cold (post) crystallization temperature T _CN in a range from 120 to 158 ° C. 25. Plate according to one of the preceding claims, wherein the plate has a surface gloss, measured according to DIN 67530 (measuring angle 20 °), of greater than 110. 26. Plate according to one of the preceding claims, wherein the plate has a light transmission, measured according to ASTM D 1003, of less than 60%. 27. Plate according to one of the preceding claims, wherein no fracture occurs when measuring the impact strength according to Charpy a _n , measured according to ISO 179/1 D. 28. Plate according to one of the preceding claims, wherein the plate has a notched impact strength a _k according to Izod, measured according to ISO 180 / 1A, in the range from 2.0 to 8.0 kJ / m ² . 29. Plate according to one of the preceding claims, wherein the plate has a scratch-resistant coating on at least one side. 30. The plate of claim 29, wherein the scratch-resistant coating contains silicon and / or acrylic. 31. A method for producing a multi-layer, colored, amorphous plate according to one of the preceding claims, wherein the thermoplastic for the at least one core layer is melted in a main extruder and the thermoplastic for the at least one cover layer in a coextruder, the melts are stacked on top of one another and the merged Layers are formed through a nozzle and then in the smoothing unit with at least two rollers calibrated, smoothed and cooled, the temperature of the first roller of the smoothing unit being in a range of 50-80 ° C. and the colorant being melted together with the thermoplastic of the layer (s) containing the colorant. 32. The method according to claim 31, wherein at least one additive is melted together with the thermoplastic of the layer to be treated with additive. 33. The method of claim 31 or 32, wherein the thermoplastic is a polyalkylene terephthalate or polyalkylene naphthalate. 34. The method of claim 33, wherein the polyalkylene terephthalate or polyalkylene naphthalate is dried for 4 to 6 hours at 160 to 180 "C before extrusion. 35. The method according to any one of claims 33 or 34, wherein the temperature of the polyalkylene terephthalate or polyalkylene naphthalate melt is in the range from 250 to 320 ° C. 36. The method according to any one of claims 31 to 35, wherein the at least one colorant and optionally the at least one additive are added via the masterbatch technology. 37. Use of a multi-layer, colored, amorphous plate according to one of the preceding claims for outdoor and indoor use.