DE19522119A1 - Pigmented amorphous sheet with good optical properties etc. - Google Patents

Abstract

Coloured amorphous sheet (I) with a thickness of 1-20 mm,contg. a crystallisable thermoplastic (II) as the main component, together with organic and/or inorganic pigment(s) (III). Also claimed is a process for the prodn. of (I), by (a) melting (II) with (III) in an extruder, (b) extruding the melt through a die, (c) calibrating, smoothing and cooling on a glazing mill with at least two rollers, the first of which is at a temp. of 50-80 deg C, and (d) cutting to size.

Description

The invention relates to an amorphous, colored, UV-stabilized plate a crystallizable thermoplastic, whose thickness ranges from 1 to 20 mm lies. The plate contains at least one UV stabilizer as a light stabilizer and at least one organic and / or one inorganic pigment as Colorant. It is characterized by homogeneous optical and very good mechanical properties. The invention further relates to a method for Manufacture of this plate and its use.

Amorphous, colored plates with a thickness between 1 and 20 mm well known. These flat structures consist of amorphous, not crystallizable thermoplastics. Typical examples of such thermoplastics, which are processed into plates are e.g. B. polyvinyl chloride (PVC), polycarbonate (PC) and polymethyl methacrylate (PMMA).

These semi-finished products are made on so-called extrusion lines (see Polymer Materials, Volume II, Technologie 1, Georg Thieme Verlag, Stuttgart, 1984). The melting of the raw material in powder or granule form is carried out in an extruder. The Amorphous thermoplastics are decreasing after extrusion as a result of that Temperature steadily increasing viscosity slightly over smoothing units or others Forming tools. Amorphous thermoplastics then have the formation of sufficient stability, d. H. a high viscosity to im Calibration tool "to stand by itself". But they're still soft enough around to be shaped by the tool. The melt viscosity and inherent stiffness of amorphous thermoplastics is so high in the calibration tool that the Semi-finished product does not collapse in the calibration tool before cooling. With easy decomposable materials such as PVC are special in the extrusion step  Processing aids such. B. processing stabilizers against decomposition and Lubricant against excessive internal friction and therefore with uncontrollable Warming necessary. Outer lubricants are required for this Prevent getting caught on walls and rollers.

When processing PMMA z. B. for the purpose of dehumidification Degassing extruder used.

In the production of plates from amorphous thermoplastics, for. T. cost intensive additives required, some of which migrate and too Production problems due to evaporation and surface coverings can lead on the semi-finished product. PVC sheets are heavy or only with special neutralization or electrolysis processes can be recycled. PC and PMMA plates are also bad and only at a loss or more extreme The deterioration of the mechanical properties is recyclable.

In addition to these disadvantages, PMMA sheets also have an extremely poor one Impact resistance and fragmentation in the event of breakage or mechanical stress. In addition, PMMA boards are combustible like wood, so these boards for example for indoor applications and in exhibition stand construction allowed to.

PMMA and PC sheets are also not cold-formable. Cold forming break PMMA sheets into dangerous fragments. When cold forming PC Panels appear hairline cracks and whitening.

EP-A-0 471 528 describes a method for molding an article a polyethylene terephthalate (PET) plate. The PET plate is in a deep-drawing mold on both sides in a temperature range between Glass transition temperature and the melting temperature heat treated. The molded PET sheet is removed from the mold when the size crystallization of the molded PET sheet in the range of 25% and 50%  lies. The PET sheets disclosed in EP-A-0 471 528 have a thickness of 1 to 10 mm. Because the deep-drawn molded body made from the PET sheet is partially crystalline and therefore no longer transparent and the Surface properties of the molded body by the deep-drawing process, the given temperatures and shapes, it is irrelevant which optical properties (e.g. gloss, cloudiness and Light transmission) have the PET plates used. As a rule, they are optical properties of these plates poor and in need of optimization. The Panels contain neither a dye nor an organic or inorganic pigment.

In addition, these plates do not contain any UV stabilizers Light stabilizers so that neither the plates nor the ones made from them Moldings are suitable for outdoor applications. Show in outdoor applications after a short time, these plates or molded articles have yellowing and a Deterioration in mechanical properties due to photo-oxidative Degradation by sunlight.

In US-A-3,496,143 the vacuum deep drawing of a 3 mm thick PET Plate whose crystallization should be in the range of 5% to 25%, described. The crystallinity of the deep-drawn molded body is greater than 25%. There are no requirements regarding these PET sheets either optical properties. Because the crystallinity of the plates used already between 5% and 25%, these plates are cloudy and opaque. The plates contain no dye and no organic or inorganic pigments as colorants. These plates also do not contain any Light stabilizers and are therefore not suitable for outdoor applications.

The object of the present invention is to provide an amorphous, colored plate to provide a thickness of 1 to 20 mm, which in addition to good mechanical and optical properties, above all, has a high UV stability.  

High UV stability means that the panels are exposed to sunlight or others UV radiation is not or only extremely little damaged, so that the Panels are suitable for outdoor applications and / or critical indoor applications. In particular, the panels should not be used for several years outdoors yellow, show no embrittlement or cracking of the surface and also have no deterioration in mechanical properties.

Good optical properties include, for example, a low one Light transmission and a high surface gloss.

The good mechanical properties include a high one Impact strength and high breaking strength.

In addition, the plate according to the invention should be recyclable, especially without loss of mechanical properties, as well as heavy flammable, so that they can also be used for indoor applications and Exhibition stand construction can be used.

The task is solved by an amorphous, colored plate with a thickness in the range of 1 to 20 mm, which as a main component a crystallizable Thermoplastics and at least one organic and / or inorganic pigment contains as a colorant, and which is characterized in that it at least contains a UV stabilizer as a light stabilizer.

The main component is the amorphous, UV-stabilized, colored plate a crystallizable thermoplastic. Suitable crystallizable or Semi-crystalline thermoplastics are, for example, polyethylene terephthalate, Polybutylene terephthalate, cycloolefin and cycloolefin copolymers, wherein Polyethylene terephthalate is preferred.

The concentration of the colorant is preferably in the range from 0.5 to 30 wt .-%, based on the weight of the crystallizable thermoplastic.  

In terms of colorants, a distinction is made between dyes according to DIN 55 944 and pigments. Pigments are under the respective processing conditions almost insoluble in the polymer, while dyes are soluble (DIN 55 949). The coloring effect of the pigments is caused by the particles themselves. The term pigment is generally a particle size of 0.01 microns to 1.0 µm bound. According to DIN 53 206, a distinction is made in the definition of Pigment particles between primary particles, aggregates and agglomerates.

Have primary particles, as they usually occur during production a pronounced due to their extremely small particle size Tendency to gather together. This creates the primary particles by aggregating the units, which is why they are smaller Have surfaces as the sum of the surface area of their primary particles corresponds. By stacking primary particles and / or aggregates Agglomerates form over corners and edges, the total surfaces of which deviates only slightly from the sum of the individual areas. If you - without further details Information - speaks of pigment particle size, refers to the Aggregates as they are essentially after coloring.

In powdered pigments, the aggregates are always agglomerates stored together, which split up during the coloring, wetted by the plastic and must be distributed homogeneously. These simultaneous processes are called dispersion. When coloring with dyes it is a solution process, as a result of which Dye is molecularly dissolved.

In contrast to the inorganic pigments, individual organic Pigments are not completely insoluble, especially not simple pigments with low molecular weights.

Dyes are adequately described by their chemical structure. However, pigments of the same chemical composition can in each case  various crystal modifications are produced and available. On A typical example of this is the white pigment titanium dioxide, which is in the rutile form and may be in the anatase form.

In the case of pigments, coating, i.e. H. by post-treatment of the Pigment particle surface, with organic or inorganic agents Improvement in performance characteristics can be achieved. This improvement lies particularly in facilitating dispersion and raising light, weather and chemical resistance. 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 are organic and / or inorganic can be coated.

The titanium dioxide particles can consist of anatase or rutile, preferably predominantly made of rutile, which has a higher opacity compared to anatase shows. In a preferred embodiment, the titanium dioxide particles exist at least 95% by weight of rutile. You can use a standard procedure e.g. B. after the chloride or sulfate process. The middle Particle size is relatively small and is preferably in the range of 0.10 to 0.30 µm.

Titanium dioxide of the type described produces within the polymer matrix no vacuoles during plate production.

The titanium dioxide particles can be coated with inorganic oxides have, as usually as a coating for TiO₂ white pigment in papers or paints are used to improve lightfastness. TiO₂ is known to be photoactive. When exposed to UV rays, free ones are formed Radicals on the surface of the particles. These free radicals can lead to the  film-forming constituents of the paint migrate to what Degradation reactions and yellowing. To the particularly suitable oxides include the oxides of aluminum, silicon, zinc or magnesium or Mixtures of two or more of these compounds.

TiO₂ particles with a coating of several of these compounds, for. B. in the EP-A-0 044 515 and EP-A-0 078 633. Furthermore, the Coating containing organic compounds with polar and non-polar groups. The organic compounds must pass through when manufacturing the plate Extrusion of the polymer melt must be sufficiently thermostable. 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, especially fatty acids and primary n-alkanols with 12 to 24 carbon atoms, as well as polydiorganosiloxanes and / or polyorganohydrogensiloxanes such as e.g. B. 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. Of the Coating is applied to the particles in aqueous suspension. The inorganic oxides are made from water-soluble compounds, e.g. B. alkali, especially sodium aluminate, aluminum hydroxide, aluminum sulfate, Aluminum nitrate, sodium silicate (water glass) or silica in the aqueous Suspension failed.

Among inorganic oxides such as Al₂O₃ and SiO₂ are the hydroxides or whose different drainage levels such. B. to understand oxide hydrates, without knowing their exact composition and structure. On the TiO₂ pigment are the after annealing and grinding in aqueous suspension Oxide hydrates e.g. B. of aluminum and / or silicon, then the pigments washed and dried. This precipitation can thus take place directly in a Suspension happen as in the manufacturing process after annealing and  subsequent wet grinding. The precipitation of the oxides and / or Oxide hydrates of the respective metals are made from the water-soluble metal salts in the known pH range, for the aluminum, for example Aluminum sulfate in aqueous solution (pH less than 4) and added of aqueous ammonia solution or sodium hydroxide solution in the pH range between 5 and 9, preferably between 7 and 8.5, the oxide hydrate precipitates. If you assume a water glass or alkali aluminate solution, the pH of the submitted TiO₂ suspension in the strongly alkaline range (pH greater than 8). The precipitation is then carried out by adding mineral acid such as sulfuric acid in the pH range from 5 to 8. After the precipitation of the metal oxides, the Suspension stirred for another 15 minutes to about 2 hours, the precipitated layers undergo aging. The coated product will separated from the aqueous dispersion and after washing at elevated Temperature, especially at 70 to 110 ° C, dried.

Typical inorganic black pigments are soot modifications, which are also can be coated, carbon pigments that differ from the carbon black pigments differ by a 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 oxidic colored pigments are iron oxide red, titanium dioxide-nickel oxide Mixed antimony oxide 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 system Zinc oxide and mixed phase pigments based on other metal oxides.

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

Examples of sulfidic pigments are cadmium sulfide selenides, cadmium Zinc sulfides, sodium aluminum silicate with sulfur bound like polysulfide in the grid.

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

Like the white and black pigments, all colored pigments can uncoated as well as inorganic and / or organically coated.

The organic colored pigments are usually divided into azo pigments and so-called non-azo pigments.

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

In special embodiments, the amorphous plate can also be mixtures of inorganic and / or organic pigments and additionally soluble Dyes included. The concentration of the soluble dye lies there preferably in the range from 0.01 to 20% by weight, particularly preferably in Range of 0.5 to 10 wt .-% based on the weight of the crystallizable Thermoplastics.

The soluble dyes are especially the fat and aromatic soluble Dyes preferred. These are azo and Anthraquinone dyes.

The concentration of the UV stabilizer as a light stabilizer is preferably in the range of 0.01 to 5 wt .-%, based on the weight of the crystallizable thermoplastics.  

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

The inhibition of these photooxidative degradation processes is significant technical and economic importance, otherwise the Applications of numerous thermoplastics drastically is restricted.

Polyethylene terephthalates, for example, start below 360 nm To absorb UV light, its absorption decreases below 320 nm considerably and is very pronounced below 300 nm. The maximal Absorption is between 280 and 300 nm.

In the presence of oxygen there are mainly chain splits, however no networking observed. Carbon monoxide, carbon dioxide and Carboxylic acids are the predominant quantity of photooxidation products In addition to the direct photolysis of the ester groups, Oxidation reactions are considered that involve peroxide radicals also result in the formation of carbon dioxide.

The photooxidation of polyethylene terephthalates can also take place Hydrogen splitting in the u-position of the ester groups to form hydroperoxides and their decomposition products as well as related chain cleavages (H. Day, D. M. Wiles: J. Appl. Polym. Sci 16, 1972, page 203).

Light stabilizers or UV stabilizers or UV absorbers are chemical Compounds involved in the physical and chemical processes of light-induced degradation can intervene. Carbon black and other pigments can partially cause light protection. These substances are for plates  unsuitable as they lead to color changes. For amorphous plates only organic and organometallic compounds suitable to the stabilizing thermoplastics no or only an extremely low color or Give color change.

Suitable light stabilizers or UV stabilizers are, for example 2-hydroxybenzophenones, 2-hydroxybenzotriazoles, organo-nickel Compounds, salicylic acid esters, cinnamic acid ester derivatives, Resorcinol monobenzoates, oxalic acid anilides, hydroxybenzoic acid esters, steric hindered amines and triazines, the 2-hydroxybenzotriazoles and the Triazines are preferred.

In a particularly preferred embodiment, the colored, amorphous plate according to the invention contains, as the main constituent, a crystallizable polyethylene terephthalate and 0.01% by weight to 5.0% by weight of 2- (4,6-diphenyl-1,3,5-triazine) -2-yl) -5- (hexyl) oxy-phenol (structure in Fig. 1a) or 0.01 wt .-% to 5.0 wt .-% 2,2'-methylene-bis (6- (2H -benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol (structure in Fig. 1b) In a preferred embodiment, mixtures of these two UV stabilizers or mixtures of at least one of the two can also be used UV stabilizers are used with other UV stabilizers, the total concentration of light stabilizer preferably being between 0.01% by weight and 5.0% by weight, based on the weight of crystallizable polyethylene terephthalate.

According to the invention, both the light stabilizer and the colorant can (inorganic and / or organic pigments and optionally dyes) in the desired concentration at the thermoplastic raw material manufacturer to be metered or metered into the extruder during plate production will.

The surface gloss of the plate according to the invention, measured according to DIN 67 530 (Measuring angle 20 °) is preferably greater than 90 and is particularly preferred  is greater than 100 and the light transmission, measured according to ASTM D 1003, is preferably less than 5%, particularly preferably less than 3%.

In addition, the plate according to the invention has a covered, homogeneous Optics on.

In the case of polyethylene terephthalate in the measurement of impact strength a _n occurs Charpy (measured according to ISO 179 / 1D) on the board preferably no fracture. 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 3.0 to 8.0 kJ / m², particularly preferably in the range from 4.0 to 6.0 kJ / m².

Polyethylene terephthalates with a crystallite melting point T _m , measured by DSC (differential scanning calorimetry) with a heating rate of 10 ° C / min from 240 ° C to 280 ° C, preferably from 250 ° C to 270 ° C, with a crystallization temperature range T _c between 75 ° C and 280 ° C, a glass transition temperature T _g between 65 ° C and 90 ° C and with a density, measured according to DIN 53 479, of 1.30 to 1.45 g / cm³ and a crystallinity between 25% and 65% are preferred polymers as starting materials for the production of the plate.

The standard viscosity SV (DCE) of the polyethylene terephthalate, measured in Dichloroacetic acid according to DIN 53 728, is preferably between 800 and 1800 between 950 and 1250, especially between 1000 and 1200.

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

IV (DCE) = 6.67 x 10 ^-4 SV (DCE) + 0.118.

The bulk density, measured according to DIN 53 466, is preferably between 0.75 kg / dm³ and 1.0 kg / dm³ and particularly preferably between 0.80 kg / dm³ and 0.90 kg / dm³.  

The polydispersity M _w / M _{n of} the polyethylene terephthalate measured by means of gel permeation chromatography is preferably between 1.5 and 4.0 and particularly preferably between 2.0 and 3.5.

According to the invention, crystallizable polyethylene terephthalate is understood

• crystallizable polyethylene terephthalate homopolymers,
• crystallizable polyethylene terephthalate copolymers,
• crystallizable polyethylene terephthalate compounds,
• - Crystallizable polyethylene terephthalate recyclate and
• - other variations of crystallizable polyethylene terephthalate.

For the purposes of the present invention, amorphous plates are such Sheets understood that, although the crystallizable thermoplastic used has a crystallinity between 25% and 65%, are not crystalline. Not crystalline, d. H. essentially amorphous means that the degree of crystallinity in generally less than 5%, preferably less than 2% and particularly preferred Is 0%.

In addition, good cold-formability without breaking became unexpected Hairline cracks and / or found without whitening, so that the invention Plate can be deformed and bent without the influence of temperature.

In addition, measurements showed that the PET plate according to the invention flame retardant and flame retardant, so that the plate according to the invention not only for outdoor applications but also for Suitable for indoor use and in exhibition stand construction.

Furthermore, the plate according to the invention is without environmental pollution and without Loss of mechanical properties easily recyclable, which makes them are particularly suitable for use as short-lived advertising signs or others Promotional items are suitable.  

Weathering tests have shown that the stabilized plates after 5 to 7 years of outdoor use no yellowing, no embrittlement, no Loss of gloss on the surface, no cracking on the surface and none Mechanical properties should deteriorate.

The colored, amorphous plate according to the invention can be produced for example after an extrusion process in an extrusion line respectively.

Such an extrusion line is shown schematically in FIG. 2. It essentially comprises

• an extruder ( 1 ) as a plasticizing system,
• - a slot die ( 2 ) as a tool for shaping,
• - a smoothing unit / calender ( 3 ) as a calibration tool,
• - a cooling bed ( 4 ) and / or a roller conveyor ( 5 ) for after-cooling,
• - a roller take-off ( 6 ),
• - a separating saw ( 7 ),
• - A side cutter ( 9 ), and if necessary
• - A stacking device ( 8 ).

The process is characterized in that the crystallizable Thermoplastic dries if necessary, then in the extruder together with the Colorant and the UV stabilizer melts, the melt through a nozzle molded and then calibrated, smoothed and cooled in the calender before one brings the plate to size.

The process for producing the plate of the invention is as follows described in detail for polyethylene terephthalate.

The addition of the light stabilizer and / or the is particularly preferred Colorants via masterbatch technology. This is the sunscreen and / or the colorant is fully dispersed in a solid carrier material. As  Carrier materials come with certain resins, the polyethylene terephthalate itself or other polymers with the polyethylene terephthalate are sufficiently tolerated.

It is important that the grain size and the bulk weight of the masterbatch similar to the grain size and bulk density of the crystallizable Thermoplastics are, so that a homogeneous distribution and thus a homogeneous UV stabilization and coloring can take place.

The drying of the polyethylene terephthalate and optionally the additive Masterbatches before extrusion are preferably carried out for 4 to 6 hours 160 to 180 ° C.

The polyethylene terephthalate and optionally the additive masterbatches are melted in the extruder. Preferably the temperature is Melt in the range of 250 to 320 ° C, the temperature of the melt essentially by both the temperature of the extruder and the Residence time of the melt in the extruder can be adjusted.

The melt then leaves the extruder through a nozzle. This nozzle is preferably a slot die.

The one melted by the extruder and shaped by a slot die PET is calibrated by smooth calender rolls, i.e. H. intensely chilled and smoothed. The calender rolls can be, for example, in an I, F, L or S shape be arranged.

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

The thickness of the PET plate is essentially the deduction that is made at the end of the Cooling zone is arranged, the cooling coupled with it  (Smoothing) rollers and the conveying speed of the extruder on the one hand and the Distance of the rollers on the other hand determined.

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

The slot die preferably consists of the separable tool body, the lips and the dust bar for flow regulation across the width. This can the control bar can be bent by tension and pressure screws. The The thickness is adjusted by adjusting the lips. It is important on one ensure that the temperature of the PET and the lip is even, otherwise the PET Melt flows out through the different flow paths to different thicknesses.

The calibration tool, d. H. the smoothing calender gives shape to the PET melt and the dimensions. This is done by freezing below the Glass transition temperature by cooling and smoothing. May be deformed no longer in this state, otherwise in this cooled state Surface defects would arise. For this reason, the Calender rolls preferably driven together. The temperature of the Calender rolls must be used to avoid sticking of the PET melt be less than the crystallite melting temperature. The PET melt leaves with the slot die at a temperature of 240 to 300 ° C. The first smooth cooling Depending on the output and plate thickness, the roller has a temperature between 50 ° C and 80 ° C. The second, somewhat cooler roller cools the second or the other Surface.

While the calibration device smoothes the PET surfaces as smoothly as possible Freezing brings and cools the profile so far that it is dimensionally stable, lowers the After-cooling device the temperature of the PET plate to almost room temperature from. After-cooling can be done on a roller bed.

The speed of the trigger should match the speed of the Calender rolls are precisely matched to defects and thickness fluctuations  to avoid.

Additional devices can be used in the extrusion line for the production of PET plates a cutting saw as a cutting device, the side trimming, the Stacking facility and a control point. The side or Edge trimming is advantageous because the thickness in the edge area may be can be uneven. At the control point, the thickness and appearance of the Plate measured.

Due to the surprising number of excellent properties, the , colored and amorphous PET plate according to the invention excellent for a Many different uses, for example for Interior cladding, for exhibition stand construction and exhibition items, for signs, for Protective glazing of machines and vehicles, in shop and shelf construction, as promotional items, as menu card stands, as basketball goal boards, as Room dividers, for aquariums and as brochure and newspaper stands. Because of the good UV stability, the colored one according to the invention is suitable amorphous PET sheet also for outdoor applications such as B. for Greenhouses, canopies, glazing, safety glasses, External cladding, covers, for applications in the construction sector, Illuminated advertising profiles, balcony cladding, roof hatches and caravan windows.

The invention is explained in more detail below on the basis of exemplary embodiments explained without being restricted thereby.

The individual properties are measured in accordance with the following Standards or procedures.  

Measurement methods Surface gloss

The surface gloss is determined in accordance with DIN 67 530. The is measured Reflector value as an optical parameter for the surface of a plate. Based on to the standards ASTM-D 523-78 and ISO 2813, the angle of incidence was included 20 ° set. A light beam strikes at the set angle of incidence the level test surface and is reflected or scattered by it. The light rays striking the photoelectronic receiver become 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 "ELREPHO" remission photometer from Zeiss, Oberkochem (DE), Standard illuminant C, 20 normal observers. The whiteness is defined as

WG = RY + 3RZ - 3RX.

WG = whiteness, RY, RZ, RX = corresponding reflection factors when used of the Y, Z and X color measurement filter. A compact is made as the white standard Barium sulfate (DIN 5033, part 9) used.

Surface defects

The surface defects are determined visually.

Charpy impact strength a _n

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

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 53 479.

SV (DCE), IV (DCE)

The standard viscosity SV (DCE) is based on DIN 53 726 in Dichloroacetic acid measured.

The intrinsic viscosity is calculated from the standard viscosity as follows

IV (DCE) = 6.67 x 10 ^-4 SV (DCE) + 0.118.

Thermal properties

The thermal properties such as crystallite 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 M _w / M _n are measured by means of gel permeation chromatography (GPC).

Weathering (both sides), UV stability

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

Test device: Atlas Ci 65 Weather Ometer
Test conditions: ISO 4892, ie artificial weathering
Irradiation time: 1000 hours (per side)
Irradiation: 05 W / m², 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 are examples and comparative examples around single-layer, covered colored plates of different thickness, which of the extrusion line described.

All plates were made according to the test specification ISO 4892, 1000 on both sides Hours per side weathered with the Atlas Ci 65 Weather Ometer from Atlas and then regarding the mechanical properties, the discoloration, the surface defects, the turbidity and the gloss checked.

example 1

A 3 mm thick, white colored, amorphous plate is produced, which as Main component is a polyethylene terephthalate and 6 wt .-% titanium dioxide as well 1.0% by weight of the UV stabilizer 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (Hexyl) oxyphenol (®Tinuvin 1577 from Ciba-Geigy) contains.

The titanium dioxide is of the rutile type and has an inorganic coating made of Al₂O₃ and with an organic coating of polydimethylsiloxane coated. The titanium dioxide has an average particle diameter of 0.2 µm.

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

1% by weight of the UV stabilizer Tinuvin is obtained directly from the raw material manufacturer in the polyethylene terephthalate incorporated.

The polyethylene terephthalate from which the colored plate is 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 53 479) is 1.41 g / cm³. 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 _w / M _{n of} the polyethylene terephthalate is 2.14. The glass transition temperature is 83 ° C.

The titanium dioxide is added in the form of a master batch. The master batch consists of 30% by weight of the titanium dioxide described as Active ingredient component and 70 wt .-% of that described Polyethylene terephthalate together as a carrier material.

Before extrusion, 80% by weight of Tinuvin 1577 with 1.0% by weight finished polyethylene terephthalate and 20% by weight of the titanium dioxide Masterbatches dried in a dryer at 170 ° C for 5 hours and then in a single screw extruder at an extrusion temperature of 286 ° C a slot die on a smoothing calender, the rollers of which are S-shaped are arranged, extruded and smoothed into a 3 mm thick plate. The first Calender roll has a temperature of 73 ° C and the subsequent rolls each have a temperature of 67 ° C. The speed of the trigger and the calender roll is 6.5 m / min.

After the after-cooling, the white, 3 mm thick PET plate with saws hemmed, cut to length and stacked at the edges.  

The white colored plate produced has the following properties:

- Thickness: 3 mm
- Surface gloss 1st page: 128
Measuring angle 20 °) 2nd side: 127
- light transmission: 0%
- Whiteness: 110
- Coloring: white, homogeneous
- Surface defects (specks, blisters, orange peel): none
- impact strength a _n Charpy no break
- Notched impact strength a _k acc. To Izod: 4.8 kJ / m²
- Cold formability: good
- Crystallinity: 0%

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

- Thickness: 3 mm
- Surface gloss 1st side: 125
(Measuring angle 20 °) 2nd side: 123
- light transmission: 0%
- Whiteness: 108%
- Coloring: white, homogeneous
- Surface defects (cracks, embrittlement): none
- impact strength a _n Charpy no break
- Notched impact strength a _k according to Izod: 4.6 kJ / m²
- Cold formability: good
- Crystallinity: 0%

Example 2

Analogously to Example 1, a dye stabilized with 1% Tinuvin 1577 is colored Plate made using a polyethylene terephthalate, the has the following characteristics:

SV (DCE): 1100
IV (DCE): 0.85 dl / g
Density: 1.38 g / cm³
Crystallinity: 44%
Crystallite melting point T _m : 245 ° C
Crystallization temperature range T _c : 82 ° C to 245 ° C
Post (cold) crystallization temperature T _CN : 152 ° C
Polydispersity M _w / M _n : 2.02
Glass transition temperature: 82 ° C

The titanium dioxide masterbatch is composed of 30% by weight of that in Example 1 described titanium dioxide and from 70 wt .-% of the polyethylene terephthalate this example together.

The extrusion temperature is 280 ° C. The first calender roll has one Temperature of 66 ° C and the subsequent rollers have a temperature of 60 ° C. The speed of the take-off and the calender rolls is included 2.9 m / min.

The produced, matte white colored PET sheet has the following Properties:

- Thickness: 6 mm
- Surface gloss 1st page: 121
(Measuring angle 20 °) 2nd side: 118
- light transmission: 0%
- Whiteness: 123
- Coloring: white, homogeneous
- Surface defects (specks, blisters, orange peel): none
- impact strength a _n Charpy no break
- Notched impact strength a _k acc. To Izod: 5.1 kJ / m²
- Cold formability: good
- Crystallinity: 0%

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

- Thickness: 6 mm
- Surface gloss 1st page: 118
(Measuring angle 20 °) 2nd side: 117
- light transmission: 0%
- Whiteness: 121%
- Coloring: white, homogeneous
- Surface defects (cracks, embrittlement): none
- impact strength a _n Charpy no break
- Notched impact strength a _k acc. To Izod: 5.0 kJ / m²
- Cold formability: good
- Crystallinity: 0%

Example 3

Analogously to Example 2, a UV-stabilized with 1.0% by weight of Tinuvin 1577, colored plate made. The extrusion temperature is 275 ° C. The the first calender roll has a temperature of 57 ° C and the following ones Rollers have a temperature of 50 ° C. The speed of the trigger and the calender roll is 1.7 m / min.  

The PET sheet produced has the following property profile:

- Thickness: 10 mm
- Surface gloss 1st page: 116
(Measuring angle 20 °) 2nd side: 114
- light transmission: 0%
- Whiteness: 132
- Coloring: white, homogeneous
- Surface defects (specks, blisters, orange peel): none
- impact strength a _n Charpy no break
- Notched impact strength a _k according to Izod: 5.3 kJ / m²
- Cold formability: good
- Crystallinity: 0%

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

- Thickness: 10 mm
- Surface gloss 1st page: 115
(Measuring angle 20 °) 2nd side: 112
- light transmission: 0%
- Whiteness: 128%
- Coloring: white, homogeneous
- Surface defects (cracks, embrittlement): none
- impact strength a _n Charpy no break
- Notched impact strength a _k acc. To Izod: 5.2 kJ / m²
- Cold formability: good
- Crystallinity: 0%

Example 4

Analogously to Example 3, a UV stabilized with 1% by weight of Tinuvin 1577 is used Colored plate made using a polyethylene terephthalate, which has the following characteristics:

SV (DCE): 1200
IV (DCE): 0.91 dl / g
Density: 1.37 g / cm³
Crystallinity: 36%
Crystallite melting point T _m : 242 ° C
Crystallization temperature range T _c : 82 ° C to 242 ° C
Post (cold) crystallization temperature T _CN : 157 ° C
Polydispersity M _w / M _n : 2.2
Glass transition temperature: 82 ° C

The titanium dioxide masterbatch is composed of 30% by weight of that in Example 1 described titanium dioxide and from 70 wt .-% of the polyethylene terephthalate this example together.

The extrusion temperature is 274 ° C. The first calender roll has one Temperature of 50 ° C and the subsequent rollers have a temperature of 45 ° C. The speed of the take-off and the calender rolls is included 1.2 m / min.

The white colored PET sheet produced shows the following property profile:

- Thickness: 15 mm
- Surface gloss 1st page: 112
(Measuring angle 20 °) 2nd side: 111
- light transmission: 0%
- Whiteness: 138
- Coloring: white, homogeneous
- Surface defects (specks, blisters, orange peel): none
- impact strength a _n Charpy no break
- Notched impact strength a _k according to Izod: 5.4 kJ / m²
- Cold formability: good
- Crystallinity: 0.4%

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

- Thickness: 15 mm
- Surface gloss 1st page: 110
(Measuring angle 20 °) 2nd side: 109
- light transmission: 0%
- Whiteness: 134%
- Coloring: white, homogeneous
- Surface defects (specks, blisters, orange peel): none
- impact strength a _n Charpy no break
- Notched impact strength a _k acc. To Izod: 5.2 kJ / m²
- Cold formability: good
- Crystallinity: 0.4%

Example 5

Analogously to Example 2, a UV-stabilized with 1.0% by weight ®Tinuvin 1577, colored plate made. 50 wt .-% of the polyethylene terephthalate Example 2 with 30 wt .-% recyclate from this polyethylene terephthalate and 20 wt .-% of the titanium dioxide masterbatch mixed.  

The colored PET sheet produced has the following property profile:

- Thickness: 6 mm
- Surface gloss 1st page: 119
(Measuring angle 20 °) 2nd side: 118
- light transmission: 0%
- Whiteness: 125
- Coloring: white, homogeneous
- Surface defects (specks, blisters, orange peel): none
- impact strength a _n Charpy no break
- Notched impact strength a _k acc. To Izod: 5.0 kJ / m²
- Cold formability: good
- Crystallinity: 0%

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

- Thickness: 6 mm
- Surface gloss 1st page: 116
(Measuring angle 20 °) 2nd side: 116
- light transmission: 0%
- Whiteness: 122%
- Coloring: white, homogeneous
- Surface defects (specks, blisters, orange peel): none
- impact strength a _n Charpy no break
- Notched impact strength a _k acc. To Izod: 4.7 kJ / m²
- Cold formability: good
- Crystallinity: 0%

Example 6

Analogously to example 2, a white-colored plate is produced. As UV 0.8% 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 Fa. Ciba-Geigy), based on the weight of the polymer.

Tinuvin 360 has a melting point of 195 ° C and is up to approx. 350 ° C thermally stable.

As in Example 1, 0.8% by weight of the UV stabilizer Tinuvin 360 becomes direct incorporated into the polyethylene terephthalate at the raw material manufacturer.

The UV-stabilized plate produced has the following properties:

- Thickness: 6 mm
- Surface gloss 1st page: 123
(Measuring angle 20 °) 2nd side: 122
- light transmission: 0%
- Whiteness: 128
- Coloring: white, homogeneous
- Surface defects (specks, blisters, orange peel): none
- impact strength a _n Charpy no break
- Notched impact strength a _k acc. To Izod: 5.2 kJ / m²
- Cold formability: good
- Crystallinity: 0%

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

- Thickness: 6 mm
- Surface gloss 1st page: 118
(Measuring angle 20 °) 2nd side: 117
- light transmission: 0%
- Whiteness: 123%
- Coloring: white, homogeneous
- Surface defects (specks, blisters, orange peel): none
- impact strength a _n Charpy no break
- Notched impact strength a _k acc. To Izod: 5.0 kJ / m²
- Cold formability: good
- Crystallinity: 0%

Comparative Example 1

Analogously to Example 1, a white-colored, UV-stabilized plate is produced. The polyethylene terephthalate used 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 within the measurement accuracy with the Properties of the polyethylene terephthalate from Example 1 identical. The Titanium dioxide masterbatch, the process parameters and the temperature as selected in Example 1. Due to the low viscosity there is none Plate production possible. The melt stability is insufficient, so that the The melt collapses on the calender rolls before cooling.

Comparative Example 2

Analogously to example 1, a white-colored plate is produced. In contrast to Example 1 contains the plate or the polyethylene terephthalate no UV Stabilizer. The polyethylene terephthalate used, the titanium dioxide, the  Extrusion parameters, the process parameters and the temperatures are as selected in Example 1.

The non-UV stabilized, colored plate produced has the following Property profile:

- Thickness: 3 mm
- Surface gloss 1st side: 130
(Measuring angle 20 °) 2nd side: 127
- light transmission: 0%
- Whiteness: 113
- Coloring: white, homogeneous
- Surface defects (specks, blisters, orange peel): none
- impact strength a _n Charpy no break
- Notched impact strength a _k acc. To Izod: 4.9 kJ / m²
- Cold formability: good
- Crystallinity: 0%

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

- Thickness: 3 mm
- Surface gloss 1st page: 88
(Measuring angle 20 °) 2nd side: 86
- light transmission: 0%
- Whiteness: 81%
- Color: white-yellowish
- Surface defects (cracks, embrittlement): surface is dull and shows a strong yellowing
- Impact strength a _n according to Charpy: perfect break at 44.2 kJ / m²
- Notched impact strength a _k acc. To Izod: 1.6 kJ / m²
- Cold formability: cracking
- Crystallinity: 0%

Visually, the plate shows a strong yellowing.

Claims (24)

1. Colored, amorphous plate, with a thickness in the range of 1 to 20 mm, which contains as a main component a crystallizable thermoplastic and at least one organic and / or inorganic pigment as a colorant, characterized in that it contains at least one UV stabilizer as a light stabilizer . 2. Plate according to claim 1, characterized in that the concentration of the pigment in the range of 0.5 to 30 wt .-%, based on the Weight of the crystallizable thermoplastic. 3. Plate according to claim 1 or 2, characterized in that the plate additionally contains a soluble dye. 4. Plate according to at least one of the preceding claims, characterized characterized in that the concentration of the UV stabilizer in the range from 0.01 to 5 wt .-%, based on the weight of the crystallizable Thermoplastics. 5. Plate according to at least one of the preceding claims, characterized characterized in that 2-hydroxybenzotriazoles as UV stabilizers and / or triazines can be used. 6. Plate according to at least one of the preceding claims, characterized characterized in that 2- (4,6-diphenyl-1,3,5-triazine-2- yl) -5- (hexyl) oxy-phenol and / or 2,2′-methylene-bis (6- (2H-benzotriazol-2- yl) -4- (1,1,3,3-tetramethylbutyl) phenol is used. 7. Plate according to at least one of the preceding claims, characterized characterized in that the surface gloss, measured according to DIN 67 530 (Measuring angle 20 °) is greater than 90.   8. Plate according to at least one of the preceding claims, characterized characterized in that the light transmission, measured according to ASTM D 1003, is less than 5%. 9. Plate according to at least one of the preceding claims, characterized characterized in that as a crystallizable thermoplastic Polyethylene terephthalate, polybutylene terephthalate, a cycloolefin and / or a cycloolefin copolymer is used. 10. Plate according to claim 9, characterized in that as Crystallizable thermoplastic polyethylene terephthalate is used. 11. Plate according to claim 10, characterized in that the Contains polyethylene terephthalate, polyethylene terephthalate recyclate. 12. Plate according to claim 10 or 11, characterized in that when measuring the impact strength a _n according to Charpy, measured according to ISO 179 / 1D, no breakage occurs. 13. Plate according to at least one of claims 10 to 12, characterized in that the notched impact strength a _k according to Izod, measured according to ISO 180 / 1A, is in the range from 3.0 to 8.0 kJ / m². 14. Plate according to at least one of claims 10 to 13, characterized characterized in that the polyethylene terephthalate is preferably a Crystallite melting point, measured by DSC with a Heating rate of 10 ° C / min., In the range of 240 to 280 ° C. 15. Plate according to at least one of claims 10 to 14, characterized characterized in that the polyethylene terephthalate is preferably a Crystallization temperature, measured by DSC with a  Heating rate of 10 ° C / min., In the range of 75 to 280 ° C having. 16. Plate according to at least one of claims 10 to 15, characterized characterized in that the polyethylene terephthalate used a Has crystallinity that is in the range of 25 to 65%. 17. Plate according to at least one of claims 10 to 16, characterized characterized in that the polyethylene terephthalate used a Standard viscosity SV (DCE), measured in dichloroacetic acid according to DIN 53 728, which is in the range from 800 to 1800. 18. A method for producing a colored, amorphous plate according to at least one of claims 1 to 17, characterized in that if necessary, the crystallizable thermoplastic is dried, then in Extruder together with the colorant and the UV stabilizer melts, the melt is shaped through a nozzle and then in the Smoothing calibrated with at least two rollers, smoothes and cools before the plate is made to measure. 19. The method according to claim 18, characterized in that the Crystallizable thermoplastic is polyethylene terephthalate. 20. The method according to claim 19, characterized in that one Polyethylene terephthalate before extrusion for 4 to 6 hours at 160 to Dries 180 ° C. 21. The method according to at least one of claims 18 to 20, characterized marked that the addition of the UV stabilizer over the Masterbatch technology is carried out.   22. The method according to at least one of claims 19 to 21, characterized characterized in that the temperature of the PET melt in the range of 250 to 320 ° C is. 23. The method according to at least one of claims 18 to 22, characterized characterized in that the first roller of the calender has a temperature has, which is in the range of 50 to 80 ° C. 24. Use of a colored, amorphous plate according to at least one of claims 1 to 17 outdoors.