DE19610956A1 - Amorphous plate made of a crystallizable polyalkylene naphthalate - Google Patents

Abstract

The invention concerns an amorphous plate which is between 1 and 20 mm thick and is characterized in that its main component is at least one polyalkylene naphthalate. The invention further concerns a process for producing this plate.

Description

The invention relates to an amorphous plate made of at least one crystallizable polyalkylene naphthalate, the thickness of which ranges from 1 to 20 mm lies. The plate is characterized by very good optical and mechanical Properties. The invention further relates to a method of manufacture this plate.

Amorphous plates with a thickness between 1 and 20 mm are sufficient known. These flat structures consist of amorphous, not crystallizable Thermoplastics. Typical examples of such thermoplastics that form sheets are processed, for. B. polyvinyl chloride (PVC), polycarbonate (PC) and Polymethyl methacrylate (PMMA). These semi-finished products are based on so-called Extrusion lines manufactured (see Polymer Materials, Volume II, Technology 1, P. 136, Georg Thieme Verlag, Stuttgart, 1984). The melting of the powder or granular raw material takes place in an extruder. The amorphous Thermoplastics are after extrusion as a result of decreasing 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. At easily decomposable materials such. B. PVC are special in extrusion Processing aids such. B. processing stabilizers against decomposition and Lubricant against excessive internal friction and therefore 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. costly 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 Deterioration of mechanical properties 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 that they can be used for Indoor applications and in exhibition stand construction may not be used.

PMMA and PC sheets are also not cold-formable. Cold forming break PMMA sheets into dangerous fragments. When cold forming PC boards experience 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 the crystallization of the molded PET sheet is in the range of 25 to 50%.

The PET sheets disclosed in EP-A-0 471 528 have a thickness of 1 to 10 mm. Because the thermoformed molded article made from this 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.

In US-A-3,496,143 the vacuum deep drawing of a 3 mm thick PET sheet, 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 object of the present invention is to provide an amorphous plate with a thickness from 1 to 20 mm to provide both good mechanical as well has optical properties.

Depending on the embodiment, the good optical properties include for example a high light transmission, a high surface gloss, a extremely low haze and high clarity.

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.  

This task is solved by an amorphous plate with a thickness in the area from 1 to 20 mm, which is characterized in that it is the main component contains at least one crystallizable polyalkylene naphthalate.

The main component of the amorphous plate contains at least one crystallizable one Polyalkylene naphthalate. Preferred are polyethylene naphthalate, Polypropylene naphthalate and polybutylene naphthalate, wherein Polyethylene naphthalate (PEN) is particularly preferred.

The amorphous plate can be colored transparent, colored or covered be colored.

In the transparent embodiment, the amorphous plate has one Surface gloss, measured according to DIN 67530 (measuring angle 200), the larger than 110, preferably greater than 120. The light transmission, measured according to ASTM D 1003 is more than 80%, preferably more than 82% and the turbidity of the plate, also measured according to ASTM D 1003, is less than 15%, preferably less than 11%.

The sharpness of the transparent plate, which is also called Clarity, and is determined at an angle smaller than 2.5 (ASTM D 1003) preferably over 90% and particularly preferably over 92%.

In the transparent colored embodiment, the amorphous plate contains at least one soluble dye. The concentration of soluble dye is preferably in the range from 0.001 to 20% by weight, based on the Weight of the polyalkylene naphthalate.

Soluble dyes are substances in the polymer are molecularly solved (DIN 55949).  

The color change as a result of the coloring of the amorphous plate is due on the wavelength-dependent absorption and / or scattering of light. Dyes can only absorb light, not scatter it, because the physical A certain minimum particle size is required for scattering.

Coloring with dyes is a solution process. As The result of this solution process is the dye, for example in solved the PEN polymer. Such coloring is transparent or translucent or translucent or opal.

Of the different classes of soluble dyes, especially those fat and aromatic soluble dyes preferred. It is about for example azo and anthraquinone dyes. They are suitable especially for coloring PEN, because of the high Glass transition temperature of PEN, the migration of the dye is restricted is (literature J. Koerner: Soluble dyes in the plastics industry in "VDI society Plastics technology: coloring of plastics, VDI-Verlag, Düsseldorf 1975).

Suitable soluble dyes are, for example: Solvent yellow 93 a Pyrazolone derivative, solvent yellow 16 a fat-soluble azo dye, fluorol green gold a fluorescent polycyclic dye, solvent red 1 an azo dye, Azo dyes such as Thermoplastrot BS, Sudanrot BB, Solventrot 138 Anthraquinone derivative, fluorescent benzopyran dyes such as fluorol red GK and fluorine orange GK, solvent blue 35 an anthraquinone dye, solvent blue a phthalocyanine dye and many others. Mixtures are also suitable of two or more of these soluble dyes.

According to the invention, the soluble dye can be used in the desired concentration already metered in at the raw material manufacturer or during plate production be metered into the extruder.  

However, the addition of the color additive via the Master batch technology. The soluble dye is in a solid Carrier material fully dispersed and / or dissolved. Come as a backing certain resins, the polyalkylene naphthalate itself or other polymers, which are sufficiently compatible with the polyalkylene naphthalate.

It is important that the grain size and the bulk weight of the masterbatch are similar to the grain size and bulk density of the polyalkylene naphthalate, so that a homogeneous distribution and thus a homogeneous, transparent Coloring can take place.

The surface gloss of the transparent colored panel, measured according to DIN 67530 (measuring angle 20 °) is greater than 100, preferably greater than 110, that Light transmission, measured according to ASTM D 1003, is in the range from 5 to 80%, preferably in the range from 10 to 70% and the cloudiness of the plate, measured according to ASTM D 1003, is in the range from 2 to 40%, preferably in the range of 3 to 35%.

In the colored embodiment, the amorphous plate contains at least one organic and / or inorganic pigment as a colorant. The concentration the colorant is preferably in the range from 0.5 to 30% by weight on the weight of the polyalkylene naphthalate.

In terms of colorants, a distinction is made between dyes according to DIN 55944 and pigments. Pigments are under the respective processing conditions almost insoluble in the polymer, while dyes are soluble (DIN 55949). 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 53206, 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 optionally organic and / or can be inorganic 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 organic compounds with polar and non-polar groups contain. The organic compounds must be used in the manufacture of the plate be sufficiently thermostable 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 C 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, as well Polydiorganosiloxanes and / or polyorganohydrogensiloxanes such as. 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 The coating is preferably applied to the particles in an aqueous suspension upset. The inorganic oxides are made from water-soluble Connections, e.g. B. alkali, in particular sodium aluminate, aluminum hydroxide, Aluminum sulfate, aluminum nitrate, sodium silicate (water glass) or silica precipitated in the aqueous suspension.

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 the subsequent wet grinding occurs. 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 as well as copper, chrome and 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 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 system Nickel-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 sulfide, sodium aluminum silicate with sulfur bound like polysulfide in the grid.  

Examples of chromates are the lead chromates that exist in the crystal forms can be monoclinic, 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 dyes and mixtures of the azo pigments.

The amorphous colored plate contains at least one inorganic and / or organic pigment. In special embodiments, the amorphous plate also mixtures of inorganic and / or organic pigments as well additionally contain soluble dyes. 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 polyalkylene naphthalate.

According to the invention, the colorants (inorganic and / or organic Pigments and optionally dyes) in the desired concentration already metered in at the raw material manufacturer or during plate production be metered into the extruder.

However, the addition of the color additive (s) via the Masterbatch technology or via the solid pigment preparation. The organic and / or inorganic pigment and optionally the soluble dye are fully dispersed in a solid carrier material. Come as a carrier certain resins, the polymer to be colored itself or other polymers, which are sufficiently compatible with the polyalkylene naphthalate.  

It is important that the grain size and the bulk density of the solid pigment preparation or the masterbatch similar to the grain size and the Bulk weight of the polyalkylene naphthalate are, so that a homogeneous Distribution and thus coloring can take place.

The surface gloss of the colored panel, measured according to DIN 67530 (Measuring angle 20 °) is preferably greater than 90 and the light transmission, measured according to ASTM D 1003, is preferably less than 5%.

In addition, the colored plate has a muted, homogeneous look.

In a further preferred embodiment, the amorphous plate contains furthermore at least one UV stabilizer as a light stabilizer, the Concentration of the UV stabilizer, preferably between 0.01 and 5% by weight, based on the weight of the polyalkylene naphthalate.

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

Polyalkylene naphthalates, 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 quantities Photo oxidation products. In addition to the direct photolysis of the ester groups still need to be considered, oxidation reactions that are about Peroxide radicals also result in the formation of carbon dioxide.

The photooxidation of polyalkylene naphthalates can also Hydrogen splitting in the α-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).

UV stabilizers or UV absorbers as light stabilizers 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. However, these substances are for Transparent sheets are unsuitable as they can discolor or change color to lead. For transparent, amorphous plates only organic and organometallic compounds suitable to the stabilized Thermoplastics no or only an extremely slight color or color change to lend.

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

In a particularly preferred embodiment, the inventive The main component of the amorphous plate is a crystallizable polyethylene naphthalate  and 0.01% to 5.0% by weight of 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) oxy-phenol or 0.01% by weight to 5.0% by weight of 2,2'-methylene-bis (6- (2H- benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol. In a preferred one Embodiments can also be mixtures of these two UV stabilizers or mixtures of at least one of these two UV stabilizers other UV stabilizers are used, the total concentration of light stabilizers, preferably between 0.01% by weight and 5.0% by weight, based on the weight of crystallizable polyethylene naphthalate.

According to the invention, crystallizable polyalkylene naphthalate is understood

• crystallizable polyalkylene naphthalate homopolymers,
• crystallizable polyalkylene naphthalate copolymers,
• crystallizable polyalkylene naphthalate compounds,
• - Crystallizable polyalkylene naphthalate recyclate and
• - other variations of crystallizable polyalkylene naphthalate.

Preferred copolymers or compounds are mixtures of Polyalkylene naphthalates and polyalkylene terephthalates, in particular Mixtures of polyethylene naphthalate (PEN) and polyethylene terephthalate (PET).

For the purposes of the present invention, amorphous plates are such Sheets understood that, although the crystallizable thermoplastic used preferably has a crystallinity between 10 and 65%, not crystalline are. Not crystalline, i.e. H. essentially amorphous means that the Degree of crystallinity is generally below 5%, preferably below 2% and is particularly preferably 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 invention Polyalkylene naphthalate plate is flame-retardant and flame-retardant, so that it is suitable for indoor applications and trade fair construction, for example.

Furthermore, the plate according to the invention is without environmental pollution and without Loss of mechanical properties easily recyclable, making them for example for use as short-lived advertising signs or other promotional items.

In a particularly preferred embodiment, the inventive Amorphous plate as the main component of crystallizable polyethylene naphthalate.

In the case of polyethylene naphthalate 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 2.0 to 12.0 kJ / m², particularly preferably in the range from 3.0 to 8.0 kJ / m².

Polyethylene naphthalates 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 300 ° C, preferably from 250 ° C to 290 ° C, with a crystallization temperature range Tc between 100 ° C and 290 ° C, a glass transition temperature T _g between 100 ° C and 140 ° C and with a density, measured according to DIN 53479, from 1.30 to 1.45 g / cm³ and a crystallinity between 10% and 65% preferred starting materials for the production of the plate are polymers.

The standard viscosity SV (DCE) of polyethylene naphthalate, measured in  Dichloroacetic acid according to DIN 53728, is between 600 and 1400, preferably between 750 and 1250 and particularly preferably between 800 and 1100.

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

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

The bulk density, measured according to DIN 53466, 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 of the polyethylene naphthalate M _w / M _n measured by GPC is preferably between 1.5 and 4.0 and particularly preferably between 2.0 and 3.5.

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

Such an extrusion line is shown schematically in FIG. 1. 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 polyalkylene naphthalate  optionally drying, then in the extruder, optionally together with the soluble dye, the colorant and / or the UV stabilizer melts, forms the melt through a nozzle and then in the smoothing unit calibrated, smoothed and cooled before the plate is made to measure.

The addition of the soluble dye, the colorant and / or the UV stabilizers are preferably made using masterbatch technology. Doing so the soluble dye, the colorant and / or the UV stabilizer in one solid carrier material fully dispersed. Certain come as carrier materials Resins, the polyalkylene naphthalate itself or other polymers with are sufficiently compatible with the polyalkylene naphthalate.

The process for producing the plate of the invention is as follows for polyethylene naphthalate (PEN) described in detail.

The drying of the PEN's before the extrusion is preferably carried out for 4 to 6 Hours at 160 to 180 ° C.

The PEN and, if applicable, the additive masterbatches are then in the Extruder melted. The temperature of the PEN melt is preferably in the range of 250 to 320 ° C, the temperature of the melt in essentially both by 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 PEN is calibrated by smooth calender rolls, i.e. H. intensely chilled and smoothed. The calender rolls can for example be in an I, F, L or S-shape can be arranged.  

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

The thickness of the PEN plate is essentially the deduction that the end of the Cooling zone is arranged, the cooling (smoothing) rollers coupled with it in terms of speed 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 dismountable Tool body, the lips and the dust bar for flow regulation over the Width. For this purpose, the control bar can be bent by tension and pressure screws will. The thickness is adjusted by adjusting the lips. Important is make sure that the temperature of the PEN and the lip is even, because otherwise the PEN melt through the different flow paths of different thickness flows out.

The calibration tool, d. H. the smoothing calender gives shape to the PEN melt and the dimensions. This is done by freezing below the Glass transition temperature by cooling and smoothing. Be deformed should no longer be 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 PEN melt be less than the crystallite melting temperature. The PEN melt leaves with the slot die at a temperature of 240 to 300 ° C. The first smoothing-cooling roller has a temperature between 50 ° C depending on the output and plate thickness and 80 ° C. The second, somewhat cooler roller cools the second or the other Surface.  

While the calibration device smooths the PEN 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 PEN plate to almost room temperature from. After-cooling can be done on a roller board. The speed the take-off should be accurate with the speed of the calender rolls be coordinated to avoid defects and thickness fluctuations.

Additional equipment can be used in the extrusion line for the production of PEN panels 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 Amorphous polyalkylene naphthalate plate according to the invention excellent for one Many different uses, for example for Interior cladding, for stand construction and articles, as displays, for Signs, for protective glazing of machines and vehicles, in Lighting sector, in shop and shelf construction, as promotional items, as Menu card stands, as basketball goal boards, as room dividers and for Outdoor applications, for example as a glass replacement.

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.

Light transmission

Under the light transmission is the ratio of the total let through To understand light to the incident amount of light.

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

Turbidity and Clarity

Haze is the percentage of light that passes through the radiated light beam deviates on average by more than 2.5. The Sharpness is determined at an angle less than 2.5.

The haze and clarity are measured using the "Hazegard plus" measuring device ASTM 1003 measured.

Whiteness

The degree of whiteness is determined using the electrical "ELREPHO" remission photometer from Zeiss, Oberkochem (DE),  Standard illuminant C, 2 ° normal observer. The whiteness is defined as

WG = RY + 3RZ - 3RX

WG = whiteness, RV, 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 179/1 D.

Notched 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 based on DIN 53 726 in Dichloroacetic acid measured.

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

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.

Color change

The color change of the samples after artificial weathering is included measured using a spectrophotometer according to DIN 5033.  

The following applies:

ΔL: difference in brightness
+ ΔL: The sample is lighter than the standard
-ΔL: The sample is darker than the standard

ΔA: difference in the red-green area
+ ΔA: The sample is redder than the standard
-ΔA: The sample is greener than the standard

ΔB: difference in the blue-yellow range
+ ΔB: The sample is more yellow than the standard
-ΔB: The sample is bluer than the standard

ΔE: total color change

The greater the numerical deviation from the standard, the greater the Color difference.

Numerical values of 0.3 are negligible and mean that none significant color change is present.

Yellowness index

The yellowness index G is the deviation from the colorlessness in the direction of "yellow" and is measured according to DIN 6167. Yellow value G values of 5 are visual not visible.

The following are examples and comparative examples in each case around single-layer panels of different thickness, which on the extrusion line described are produced.

example 1

The polyethylene naphthalate from which the transparent plate is made has a standard viscosity SV (DCE) of 810, which corresponds to an intrinsic viscosity IV (DCE) of 0.65 dl / g. The moisture content is <0.2% and the density (DIN 53479) is 1.33 g / cm³. The crystallinity is 15%, the crystallite melting point according to DSC measurements being 270 ° C. The polydispersity M _w / M _{n of} the polyethylene naphthalate is 2.14. The glass transition temperature is 119 ° C.

Before extrusion, the polyethylene naphthalate is 5 hours at 170 ° C. dried in a dryer and then in a single screw extruder at a Extrusion temperature of 286 ° C through a slot die on one Smoothing calender whose rolls are arranged in an S-shape, extruded and into one 2 mm thick plate smoothed. The first calender roll has a temperature of 65 ° C and the subsequent rollers each have a temperature of 58 ° C.

The speed of the take-off and the calender rolls is 4.0 m / min.

After cooling, the transparent, 2 mm thick PET plate Edged, cut to length and stacked with saws on the edges.

The transparent PEN sheet produced has the following property profile:

- Thickness: 2 mm
- Surface gloss 1st page: 170
(Measuring angle 20 °) 2nd side: 165
- Light transmission: 86%
- Clarity: 98%
- turbidity: 1.5%
- Surface defects per m² (specks, orange peel, blisters, etc.): none
- impact strength a _n Charpy no break
- Cold formability: good, no defects
- Crystallinity: 0%
- Density: 1.31 g / cm³.

Example 2

Analogous to Example 1, a transparent plate is produced, with a Polyethylene naphthalate is used, which has the following properties:

SV (DCE): 1100
IV (DCE): 0.85 dl / g
Density: 1.32 g / cm³
Crystallinity: 24%
Crystallite melting point T _m : 254 ° C
Polydispersity M _w / M _n : 2.02
Glass transition temperature: 117 ° C

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 1.9 m / min.

The transparent PEN sheet produced has the following property profile:

- Thickness: 6 mm
- Surface gloss 1st page: 172
(Measuring angle 20 °) 2nd side: 170
- Light transmission: 88.1%
- Clarity: 99.6%
- turbidity: 2.6%
- Surface defects per m² (specks, orange peel, blisters, etc.): none
- impact strength a _n Charpy no break
- Cold formability: good, no defects
- Crystallinity: 0%
- Density: 1.32 g / cm³

Example 3

Analogous to example 2, a transparent plate is produced. The Extrusion temperature is 275 ° C. The first calender roll has one Temperature of 57 ° C and the subsequent rollers have a temperature of 50 ° C. The speed of the take-off and the calender rolls is included 1.7m / min.

The PEN board produced has the following property profile:

- Thickness: 10 mm
- Surface gloss 1st page: 151
(Measuring angle 20 °) 2nd side: 148
- Light transmission: 86.5%
- Clarity: 99.2%
- Turbidity: 4.95%
- Surface defects per m² (specks, orange peel, blisters, etc.): none
- impact strength a _n Charpy no break
- Cold formability: good, no defects
- Crystallinity: 0.1%
- Density: 1.33 g / cm³

Example 4

Analogous to example 2, a transparent plate is produced. 70% Polyethylene naphthalate from Example 2 with 30% recyclate from this  Mixed polyethylene naphthalate.

The transparent PEN sheet produced has the following property profile:

- Thickness: 6 mm
- Surface gloss 1st page: 168
(Measuring angle 20 °) 2nd side: 166
- Light transmission: 87.3%
- Clarity: 99.4%
- turbidity: 3.2%
- Surface defects per m² (specks, orange peel, blisters, etc.): none
- impact strength a _n Charpy no break
- Cold formability: good, no defects
- Crystallinity: 0%
- Density: 1.32 g / cm³

Example 5

A 6 mm thick, transparently colored, amorphous plate is produced, which as the main constituent is the polyethylene naphthalate from Example 2 and 2% by weight of the soluble dye Solventrot 138, an anthraquinone derivative from BASF (®Thermoplast G) contains.

The soluble dye Solventrot 138 is in the form of a masterbatch admitted. The masterbatch consists of 20% by weight of the dye Solvent red 138 and 80 wt .-% of that described above Polyethylene naphthalate together.

Before the extrusion, 90% by weight of the polyethylene naphthalate and 10% by weight the master batch is dried in a dryer at 170 ° C. for 5 hours and then in a single screw extruder at an extrusion temperature of 280 ° C  through a slot die on a smoothing calender, the rollers of which are S-shaped are arranged, extruded and smoothed into a 6 mm thick plate. The first Calender roll has a temperature of 66 ° C and the subsequent rolls each have a temperature of 60 ° C. The speed of the trigger and the calender roll is 2.9 m / min.

After the cooling, the transparent colored, 6 mm thick PEN board lined with cutting saws on the edges, cut to length and stacked.

The PEN plate produced, colored red-transparent, has the following Property profile:

- Thickness: 6 mm
- Surface gloss 1st page: 118
(Measuring angle 20 °) 2nd side: 115
- Light transmission: 28.1%
- Clarity: 97.1%
- turbidity: 9.6%
- Surface defects per m² (specks, orange peel, blisters, etc.): none
- impact strength a _n Charpy no break
- Cold formability: good, no defects
- Crystallinity: 0%
- Density: 1.34 g / cm³

Example 6

A 3 mm thick, white colored, amorphous plate is produced, which as The main component is the polyethylene naphthalate from Example 2 and 6% by weight  Contains titanium dioxide.

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.

The titanium dioxide is added in the form of a master batch. The master batch consists of 30 wt .-% of the described titanium dioxide and 70 wt .-% of described polyethylene naphthalate together.

Before the extrusion, 80% by weight of the polyethylene naphthalate and 20% by weight the titanium dioxide masterbatch in a dryer at 170 ° C. for 5 hours dried and then in a single screw extruder at a Extrusion temperature of 286 ° C through a slot die on one Smoothing calender, the rollers of which are arranged in an S-shape, extruded and into one 3 mm thick plate smoothed. The first calender roll has a temperature of 73 ° C and the subsequent rollers each have a temperature of 67 ° C. The speed of the take-off and the calender rolls is 6.5 m / min.

After the after-cooling, the white, 3 mm thick PEN 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: 123
(Measuring angle 20 °) 2nd side: 122
- light transmission: 0%
- Whiteness: 110
- Coloring: white, homogeneous
- Surface defects (specks, blisters, orange peel, etc.): none
- impact strength a _n Charpy no break
- Cold formability: good
- Crystallinity: 0%

Example 7

A 3 mm thick, transparent, amorphous plate is produced, which as The main component is the polyethylene naphthalate from Example 2 and 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.

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

For the purpose of homogeneous distribution, 1.0% by weight of the UV stabilizer is used directly incorporated into the polyethylene naphthalate at the raw material manufacturer.

Before extrusion, the polyethylene naphthalate is 5 hours at 170 ° C. dried in a dryer and then in a single screw extruder at a Extrusion temperature of 286 ° C through a slot die on one Smoothing calender whose rolls are arranged in an S-shape, extruded and into one 3 mm thick plate smoothed. The first calender roll has a temperature of 73 ° C and the subsequent rollers each have a temperature of 67 ° C. The speed of the take-off and the calender rolls is 6.5 m / min.

After cooling, the transparent, 3 mm thick PEN plate Edged, cut to length and stacked with saws on the edges.

The transparent, amorphous PEN plate produced has the following Property profile:

- Thickness: 3 mm
- Surface gloss 1st page: 168
(Measuring angle 20 °) 2nd side: 161
- Light transmission: 85%
- Clarity: 97%
- turbidity: 1.8%
- Surface defects per m² (specks, orange peel, blisters, etc.): none
- impact strength a _n Charpy no break
- Cold formability: good, no defects
- Crystallinity: 0%
- Density: 1.33 g / cm³

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

- Thickness: 3 mm
- Surface gloss 1st page: 162
(Measuring angle 20 °) 2nd side: 153
- Light transmission: 84.1%
- Clarity: 96%
- turbidity: 2.0%
- Total discoloration ΔE: 0.22
- Dark discoloration ΔL: -0.18
- Red-green discoloration ΔA: -0.08
- Blue-yellow discoloration ΔB: 0.10
- Surface defects (cracks, embrittlement): none
- Yellowness index G: 4
- impact strength a _n Charpy no break
- Cold formability: good

Claims (12)

1. Amorphous plate, with a thickness in the range of 1 to 20 mm, characterized in that it contains at least one polyalkylene naphthalate as the main component. 2. Plate according to claim 1, characterized in that it is at least contains a dye soluble in polyalkylene naphthalate. 3. Plate according to claim 1 or 2, characterized in that it at least one organic and / or inorganic pigment as Contains colorants. 4. Plate according to at least one of claims 1 to 3, characterized characterized in that they have at least one UV stabilizer Contains sunscreen. 5. Plate according to at least one of claims 1 to 4, characterized characterized in that the polyalkylene naphthalate is polyethylene, Polypropylene and / or polybutylene naphthalate is used. 6. Plate according to one of claims 1 to 5, characterized characterized in that as polyalkylene naphthalate, polyethylene naphthalate is used. 7. A method for producing an amorphous plate according to at least one of claims 1-6, characterized in that the Polyalkylene naphthalate melts in the extruder, the melt through a Molds nozzle and then in the smoothing unit with at least two Rollers are calibrated, smoothed and cooled before the plate is made to measure.   8. The method according to claim 7, characterized in that one Polyalkylene naphthalate together with the soluble dye, the Colorant and / or the UV stabilizer melts. 9. The method according to claim 7 or 8, characterized in that the polyalkylene naphthalate dries before being melted in the extruder. 10. The method according to at least one of claims 7 to 9, characterized characterized in that as polyalkylene naphthalate Polyethylene naphthalate (PEN) is used. 11. The method according to claim 10, characterized in that the Temperature of the PEN melt is in the range from 250 to 320 ° C. 12. The method according to claim 10 or 11, characterized in that the first roller of the calender has a temperature which is in the range of 50 to 80 ° C is.