EP0889778A2

EP0889778A2 - Amorphous plate of a crystallizable polyalkylene naphthalate

Info

Publication number: EP0889778A2
Application number: EP97914249A
Authority: EP
Inventors: Ursula Murschall; Rainer Brunow
Original assignee: Hoechst Research and Technology Deutschland GmbH and Co KG
Current assignee: Aventis Research and Technologies GmbH and Co KG
Priority date: 1996-03-20
Filing date: 1997-03-13
Publication date: 1999-01-13
Also published as: KR20000064699A; BR9708138A; WO1997034759A3; PL329028A1; CN1216950A; DE19610956A1; AU2156897A; JP2000507285A; WO1997034759A2; TR199801858T2; TW413689B

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

description

Amorphous plate made of a crystallizable polyalkylene naphthalate

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

Amorphous plates with a thickness between 1 and 20 mm are well known. These flat structures consist of amorphous, non-crystallizable thermoplastics. Typical examples of such thermoplastics that are processed into sheets are, for example, polyvinyl chloride (PVC), polycarbonate (PC) and polymethyl methacrylate (PMMA). These semi-finished products are manufactured on so-called extrusion lines (cf. Polymer Werkstoffe, Volume II, Technologie 1, p. 136, Georg Thieme Verlag, Stuttgart, 1984). The powdered or granular raw material is melted in an extruder. After extrusion, the amorphous thermoplastics can be easily reshaped using smoothing units or other shaping tools due to the steadily increasing viscosity as the temperature decreases. After shaping, amorphous thermoplastics then have sufficient stability, ie a high viscosity, to "stand by themselves" in the calibration tool. But they are still soft enough 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 it cools down. With easily decomposable materials such. B. PVC are special processing aids in extrusion, such as. B. Processing stabilizers against decomposition and lubricants against excessive internal friction and thus uncontrollable heating necessary. External lubricants are required to prevent snagging on walls and rollers. When processing PMMA z. B. used a degassing extruder for dehumidification.

In the production of plates from amorphous thermoplastics, for. T. costly additives are required, some of which migrate and can lead to production problems due to evaporation and surface coatings on the semi-finished product. PVC sheets are heavy or can only be recycled using special neutralization or electrolysis processes. PC and PMMA boards are also poor and can only be recycled if the mechanical properties are lost or extremely deteriorated.

In addition to these disadvantages, PMMA sheets also have extremely poor impact strength and shatter when broken or subjected to mechanical stress. In addition, PMMA panels, such as wood, are flammable, so that they must not be used, for example, for indoor applications or in trade fair construction.

PMMA and PC sheets are also not cold-formable. During cold forming, PMMA sheets break into dangerous fragments. When cold-forming PC sheets, hairline cracks and whitening occur.

EP-A-0 471 528 describes a method for molding an article from a polyethylene terephthalate (PET) plate. The PET sheet is heat treated in a deep-drawing mold on both sides in a temperature range between the glass transition temperature and the melting temperature. The molded PET sheet is taken out of the mold when the degree of crystallization of the molded PET sheet is in the range of 25 to 50%. The PET sheets disclosed in EP-AO 471 528 have a thickness of 1 to 10 mm. Since the deep-drawn molded article produced from this PET sheet is partially crystalline and therefore no longer transparent, and it is the surface properties of the molded article that are determined by the deep-drawing process, the given temperatures and shapes irrelevant what optical properties (e.g. gloss, haze and light transmission) the PET sheets used have. As a rule, the optical properties of these plates are poor and need to be optimized.

US Pat. No. 3,496,143 describes the vacuum deep drawing of a 3 mm thick PET sheet, the crystallization of which should be in the range from 5 to 25%. The crystallinity of the deep-drawn molded body is greater than 25%. No demands are made on the optical properties of these PET sheets either. Since the crystallinity of the plates used is already between 5 and 25%, these plates are cloudy and opaque.

The object of the present invention is to provide an amorphous plate with a thickness of 1 to 20 mm, which has both good mechanical and optical properties.

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

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

In addition, the plate according to the invention should be recyclable, in particular without loss of the mechanical properties, and also flame-retardant, so that it can also be used, for example, for interior applications and in trade fair construction.

This object is achieved by an amorphous plate with a thickness in the range from 1 to 20 mm, which is characterized in that it contains at least one crystallizable polyalkylene naphthalate as the main component. The main component of the amorphous plate contains at least one crystallizable polylakenyl naphthalate. Polyethylene naphthalate, polypropylene naphthalate and polγbutylene naphthalate are preferred, with polyethylene naphthalate (PEN) being particularly preferred.

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

In the transparent embodiment, the amorphous plate has a surface gloss, measured according to DIN 67530 (measuring angle 20 °), which is greater 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 haze of the plate, also measured according to ASTM D 1003, is less than 15%, preferably less than 11%.

The image sharpness of the transparent plate, which is also called Clarity, and is determined at an angle of less than 2.5 ° (ASTM D 1003), is 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 that are molecularly dissolved in the polymer (DIN 55949).

The color change as a result of the coloring of the amorphous plate is based on the wavelength-dependent absorption and / or scattering of the light. Dyes can only absorb light, not scatter, since the physical requirement for scattering is a certain minimum particle size. Coloring with dyes is a solution process. As a result of this solution process, the dye is molecularly dissolved in the PEN polymer, for example. Such coloring is referred to as transparent or translucent or translucent or opal.

Of the various classes of soluble dyes, the fat and aromatic soluble dyes are particularly preferred. These are, for example, azo and anthraquinone dyes. They are particularly suitable for coloring PEN, because due to the high glass transition temperature of PEN, the migration of the dye is restricted (literature J. Koerner: Soluble dyes in the plastics industry in "VDI-Gesellschaft Kunststofftechnik: coloring plastics, VDI-Veriag, Düsseldorf 1975).

Suitable soluble dyes are, for example: solvent yellow 93 a pyrazolone derivative, solvent yellow 16 a fat-soluble azo dye, fluorole green gold a fluorescent polycyclic dye, solvent red 1 an azo dye, azo dyes such as thermoplastic red BS, Sudan red BB, solvent red 138 an anthraquinone derivative, and fluorescent fluorophenane fluorophores such as fluorophenane GK, solvent blue 35 an anthraquinone dye, solvent blue a phthalocyanine dye and many others. Mixtures of two or more of these soluble dyes are also suitable.

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

However, the addition of the color additive via masterbatch technology is particularly preferred. The soluble dye is fully dispersed and / or dissolved in a solid carrier material. Certain resins, the polyalkylene naphthalate itself or other polymers, come as the carrier material. which are sufficiently compatible with the polyalkylene naphthalate.

It is important that the grain size and the bulk density of the masterbatch are similar to the grain size and the 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 plate, measured according to DIN 67530 (measuring angle 20 °) is greater than 100, preferably greater than 110, the 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 turbidity of the plate, measured according to ASTM D 1003, is in the range from 2 to 40%, preferably in the range from 3 to 35%.

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

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

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

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

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

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

In the case of pigments, an improvement in the properties of use can be achieved by coating, ie by post-treatment of the pigment particle surface, with organic or inorganic agents. This improvement lies in particular in facilitating the dispersion and increasing the resistance to light, weather and chemicals. Typical coating agents for pigments are, for example, fatty acids, fatty acid amides, siloxanes and aluminum oxides. Suitable inorganic pigments are, for example, the white pigments titanium dioxide, zinc sulfide and tin sulfide, which can optionally be coated organically and / or inorganically.

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

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

The titanium dioxide particles can have a coating of inorganic oxides, as is usually used as a coating for TiO ₂ white pigment in papers or paints to improve the lightfastness. As is well known, Ti0 ₂ is photoactive. When exposed to UV rays, free radicals form on the surface of the particles. These free radicals can migrate to the film-forming components of the paint, which leads to degradation reactions and yellowing. The particularly suitable oxides include the oxides of aluminum, silicon, zinc or magnesium or mixtures of two or more of these compounds. TiO ₂ particles with a coating of several of these compounds are described, for example, in EP-A-0 044 515 and EP-A-0 078 633. Furthermore, the coating can contain organic compounds with polar and non-polar groups. The organic compounds must be sufficiently thermostable in the manufacture of the plate by extrusion of the polymer melt. Polar groups are, for example, -OH, -OR, -COOX (X = R, H or Na, R = alkyl with 1 to 34 carbon atoms). Preferred organic compounds are alkanols and fatty acids with 8 to 30 carbon atoms in the alkyl group, in particular fatty acids and primary n-alkanols with 12 to 24 carbon atoms, and also polydiorganosiloxanes and / or polyorganohydrogensiloxanes such as, for example, polydimethylsiloxane and polymethylhydrogensiioxane.

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

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

Typical inorganic black pigments are carbon black modifications, which can also be coated, carbon pigments that differ from the carbon black pigments in their higher ash content and oxidic black pigments such as iron oxide black as well as copper, chromium 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-antimony oxide mixed-phase pigments, titanium dioxide-chromium oxide-antimony oxide mixed-phase pigments, mixtures of the oxides of iron, zinc and titanium, chromium oxide iron oxide brown, spinels of the cobalt-aluminum-titanium-nickel-zinc oxide system and mixed-phase pigments based on other metal oxides.

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

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

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

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

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

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

The amorphous colored plate contains at least one inorganic and / or organic pigment. In special embodiments, the amorphous plate can also contain mixtures of inorganic and / or organic pigments and additionally 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) can be metered in at the desired concentration at the raw material manufacturer or metered into the extruder during plate manufacture.

However, the addition of the color additive (s) via the masterbatch technology or via the solid pigment preparation is particularly preferred. The organic and / or inorganic pigment and optionally the soluble dye are fully dispersed in a solid carrier material. Suitable carriers are 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 are similar to the grain size and the bulk density of the polylactic naphthalate, so that a homogeneous distribution and thus coloring can take place. The surface gloss of the colored plate, 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 further contains at least one UV stabilizer as light stabilizer, the concentration of the UV stabilizer preferably being 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. the wavelength range from 280 to 400 nm initiates degradation processes in thermoplastics, as a result of which not only the visual appearance changes as a result of color change or yellowing, but also the mechanical-physical properties are adversely affected.

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

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

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

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

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

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

In a particularly preferred embodiment, the amorphous plate according to the invention contains, as the main component, a crystallizable polyethylene naphthalate 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 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 embodiment, mixtures of these two UV stabilizers can also be used or mixtures of at least one of these two UV stabilizers 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 naphthalate .

According to the invention, crystallizable polyalkylene naphthalate is understood to mean 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 plate is understood to mean those plates which, although the crystallizable thermoplastic used preferably has a crystallinity of between 10 and 65%, are not crystalline. Not crystalline, i.e. H. essentially amorphous means that the degree of crystallinity is generally below 5%, preferably below 2% and particularly preferably 0%.

In addition, good cold formability without breakage, without hairline cracks and / or without white breakage was found completely unexpectedly, so that the plate according to the invention can be deformed and bent without the effect of temperature.

In addition, measurements have shown that the polyalkylene naphthalate plate according to the invention is flame-retardant and flame-retardant, so that it is suitable, for example, for interior applications and in trade fair construction. Furthermore, the plate according to the invention can be easily recycled without environmental pollution and without loss of the mechanical properties, which makes it suitable, for example, for use as short-lived advertising slider or other promotional items.

In a particularly preferred embodiment, the amorphous plate according to the invention contains crystallizable polyethylene naphthalate as the main constituent.

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 / m ² , particularly preferably in the range from 3.0 to 8.0 kJ / m ^2nd

Polyethylene naphthalates with a crystallite melting point T _m , measured with DSC (differential scanning calorimetry) with a heating rate of 10 ^β C / min, from 240 ° C to 300 ° C, preferably from 250 ° C to 290 ° C, with a crystallization temperature range T _c between 100 ° C and 290 ° C, a glass transition temperature T _fl between 100 ^β C and 140 ° C and with a density, measured according to DIN 53479, of 1, 30 to 1, 45 g / cm ³ and a crystallinity between 10% and 65 % represent preferred polymers as starting materials for the production of the plate.

The standard viscosity SV (DCE) of the 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 ^• 10 ^'4 SV (DCE) + 0.118 The bulk density, measured according to DIN 53466, is preferably between 0.75 kg / dm ³ and 1.0 kg / dm ³ , and particularly preferably between 0.80 kg / dm ³ and 0.90 kg / dm ³ .

The polydispersity of the 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, by 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 cutting device (9), and optionally a stacking device (8).

The process is characterized in that the polyalkylene naphthalate is optionally dried, then melted in the extruder, optionally together with the soluble dye, the colorant and / or the UV stabilizer, the melt is shaped through a nozzle and then calibrated, smoothed and cooled in the calender before you get the plate to size.

The soluble dye, the colorant and / or the UV stabilizer are preferably added using masterbatch technology. The soluble dye, the colorant and / or the UV stabilizer are combined in one solid carrier material fully dispersed. Suitable carrier materials are certain resins, the polyalkylene naphthalate itself or other polymers which are sufficiently compatible with the polyalkylene naphthalate.

The process for producing the plate according to the invention is described in detail below for polyethylene naphthalate (PEN).

The PEN is dried before extrusion, preferably for 4 to 6 hours at 160 to 180 ° C.

The PEN and optionally the additive masterbatches are then melted in the extruder. The temperature of the PEN melt is preferably in the range from 250 to 320 ° C., the temperature of the melt being able to be set essentially both by the temperature of the extruder and by the residence time of the melt in the extruder.

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

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

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 determined by the take-off, which is arranged at the end of the cooling zone, the cooling (smoothing) rolls coupled with it in terms of speed and the conveying speed of the extruder on the one hand and the distance between the rolls on the other hand. Both single-screw and twin-screw extruders can be used as extruders.

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

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

While the calibration device freezes the PEN surfaces as smoothly as possible and cools the profile to such an extent that it is dimensionally stable, the post-cooling device lowers the temperature of the PEN plate to almost room temperature. After-cooling can be done on a roll board. The speed of the take-off should be exactly matched to the speed of the quayander rollers in order to avoid defects and thickness fluctuations. A separating saw as a cutting device, the side trimming, the stacking system and a control point can be located in the extrusion line for the production of PEN plates as additional devices. The side or edge trimming is advantageous because the thickness in the edge area can be uneven under certain circumstances. The thickness and appearance of the plate are measured at the control point.

Due to the surprising number of excellent properties, the amorphous polyalkylene naphthalate plate according to the invention is excellently suitable for a large number of different uses, for example for interior cladding, for trade fair construction and trade fair articles, as displays, for signs, for protective glazing of machines and vehicles, in the lighting sector, in the store. and shelf construction, as a promotional item, as a menu card stand, as a basketball goal board, as a room divider and for outdoor applications, for example as a glass replacement.

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

The individual properties are measured in accordance with the following standards and procedures.

Measurement methods

Surface gloss:

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

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 measured with the "Hazegard plus" measuring device in accordance with ASTM 1003.

Turbidity and Clarity:

Haze is the percentage of the transmitted light that deviates by more than 2.5 ° on average from the incident light beam. The image sharpness is determined at an angle of less than 2.5 °.

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

Whiteness

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

WG = RY + 3RZ - 3RX.

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

The surface defects are determined visually.

Charpy impact strength a _n:

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

Notched impact strength a _k according to Izod:

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

Density:

The density is determined according to DIN 53479.

SV (DCE), IV (DCE):

The standard viscosity SV (DCE) is based on DIN 53726 in

Dichloroacetic acid measured.

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

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

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

Atlas Ci 65 Weather Ometer test device

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

Irradiation time 1000 hours (per side)

Irradiation 05 W / m ² , 340 nm

Temperature 63 ^β C

Relative humidity 50%

Xenon lamp inner and outer filter made of borosilicate

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

Color change:

The color change of the samples after artificial weathering is measured with 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

ΔE = V ΔL ² + ΔA ² + ΔB ²

The greater the numerical deviation from the standard, the greater the

Color difference.

Numerical values of ≤0.3 are negligible and mean that there is no significant color change.

Yellowness index:

The yellowness index G is the deviation from the colorlessness in the "yellow" direction and is measured in accordance with DIN 6167. Yellow value G values of ≤5 are not visually visible.

The examples and comparative examples below each relate to single-layer sheets of different thicknesses which are produced on the extrusion line described.

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 / cm ³ . 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 1 19 "C.

Before extrusion, the polyethylene naphthalate is dried in a dryer at 170 ° C for 5 hours and then extruded in a single-screw extruder at an extrusion temperature of 286 ° C through a slot die onto a smoothing calender, the rollers of which are arranged in an S-shape, and into a 2 mm thick plate smoothed. The first calender roll has a temperature of 65 ^β 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 the after-cooling, the transparent, 2 mm thick PET plate is trimmed at the edges with separating saws, cut to length and stacked.

The transparent PEN sheet produced has the following property profile:

- thickness 2 mm

- Surface gloss on page 170

(Measuring angle 20 °) 2nd page 165

- light transmission 86%

- Clarity 98%

- turbidity 1.5%

- Surface defects per m ² none

(Specks, orange peel, blisters, etc.)

- impact strength a _n Charpy no break

- Good cold formability, no defects

- crystallinity 0%

- Density 1.31 g / cm ³

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 / cm ³

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 a temperature of 66 ° C and the subsequent rolls have a temperature of 60 ° C. The speed of the take-off and the calender rolls is 1.9 m / min.

The transparent PEN sheet produced has the following property profile:

- thickness 6 mm

- Surface gloss on page 172

(Measuring angle 20 °) 2nd page 170

- light transmission 88.1%

- Clarity 99.6%

- turbidity 2.6%

- Surface defects per m ² none

(Specks, orange peel, blisters, etc.)

- impact strength a _n Charpy no break

- Good cold formability, no defects

- crystallinity 0%

- Density 1.32 g / cm ³

Example 3:

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

The PEN board produced has the following property profile:

- thickness 10 mm

- Surface gloss 1st page 151 (measuring angle 20 ^β ) 2nd page 148

- light transmission 86.5% Clarity 99.2%

Turbidity 4.95%

Surface defects per m ² none

(Specks, orange peel, blisters, etc.)

Charpy impact strength a _n no break

Cold formability good, no defects

Crystallinity 0.1%

Density 1.33 g / cm ³

Example 4:

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

The transparent PEN sheet produced has the following property profile:

- thickness 6 mm

- Surface gloss on page 168

(Measuring angle 20 °) 2nd page 166

- light transmission 87.3%

- Clarity 99.4%

- turbidity 3.2%

- Surface defects per m ² none

(Specks, orange peel, blisters, etc.)

- impact strength a _n Charpy no break

- Cold formability: good, no defects

- crystallinity 0%

- Density 1.32 g / cm ³

Example 5:

A 6 mm thick, transparently colored, amorphous plate is produced, the main component of which is the polyethylene naphthalate from Examples 2 and 2 wt. % of the soluble dye Soiventrot 138, an anthraquinone derivative from BASF ("Thermoplast G) contains.

The soluble dye Solventrot 138 is added in the form of a masterbatch. The masterbatch is composed of 20% by weight of the solvent red 138 dye and 80% by weight of the polyethylene naphthalate described above.

Before the extrusion, 90% by weight of the polyethylene naphthalate and 10% by weight of the masterbatch are 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 onto a smoothing calender, the rollers of which S-shaped, 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 take-off and the calender rolls is 2.9 m / min.

After the after-cooling, the transparently colored, 6 mm thick PEN plate is trimmed at the edges with separating saws, cut to length and stacked.

The manufactured, red-transparent colored PEN plate has the following property professional !:

- thickness 6 mm

- Surface gloss 1st side 118 (measuring angle 20 °) 2nd side 115

- light transmission 28.1%

- Clarity 97.1%

- turbidity 9.6%

- Surface defects per m ² none (specks, orange peel, blisters, etc.)

- impact strength a _n Charpy no break Cold formability good, no defects

Crystallinity 0%

Density 1.34 g / cm ³

Example 6:

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

The titanium dioxide is of the rutile type and is coated with an inorganic coating made of Al ₂ 0 ₃ and with an organic coating made of polydimethylsiloxane. 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 masterbatch is composed of 30% by weight of the titanium dioxide described and 70% by weight of the polyethylene naphthalate described.

Prior to extrusion, are wt .-% of the polyethylene naphthalate 80 and 20% by weight of the titanium dioxide masterbatch for 5 hours at 170 C ^β dried in a dryer and then in a single screw extruder at an extrusion temperature of 286 ° C through a slot die onto a polishing calender, whose rollers are arranged in an S-shape, extruded and smoothed into a 3 mm thick plate. The first Kaianderwalze has a temperature of 73 ° C and the subsequent rolls each have a temperature of 67 ^C C. The speed of the draw-off and of the calender rolls is 6.5 m / min.

After the after-cooling, the white, 3 mm thick PEN plate is trimmed at the edges with separating saws, cut to length and stacked. The white colored plate produced shows the following properties:

3 mm thick

Surface gloss 1st page 123

Measuring angle 20 °) 2nd page 122

Light transmission 0%

Whiteness 110

Coloring white, homogeneous

No surface defects

(Specks, blisters, orange peel, etc.)

Charpy impact strength a _n 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 contains 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) oxyphenol® (Tinuvin 1577 from Ciba-Geigγ).

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

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

Before the extrusion, the polyethylene naphthalate is dried for 5 hours at 170 ° C in a dryer and then extruded in a single-screw extruder at an extrusion temperature of 286 ° C through a slot die onto a smoothing calender, the rollers of which are arranged in an S-shape, and extruded to form a 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.

Following the after-cooling, the transparent, 3 mm thick PEN plate is trimmed at the edges with separating saws, cut to length and stacked.

The transparent, amorphous PEN plate produced has the following

Property profile:

- thickness 3 mm

- Surface gloss 1st page 168

(Measuring angle 20 °) 2nd page 161

- light transmission 85%

- Clarity 97%

- turbidity 1.8%

- Surface defects per m ² none

(Specks, orange peel, blisters, etc.)

- impact strength a _n Charpy no break

- Good cold formability, no defects

- crystallinity 0%

- density 1.33 g / cm ³

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 page 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

No surface defects

(Cracks, embrittlement)

Yellowness index G 4

Charpy impact strength a _n no break

Cold formability good

Claims

Claims:

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 contains at least one dye soluble in polyalkylene naphthalate.

3. Plate according to claim 1 or 2, characterized in that it contains at least one organic and / or inorganic pigment as a colorant.

4. Plate according to at least one of claims 1 to 3, characterized in that it contains at least one UV stabilizer as a light stabilizer.

5. Plate according to at least one of claims 1 to 4, characterized in that polyethylene, polypropylene and / or polybutylene naphthalate is used as the polyalkylene naphthalate.

6. Plate according to at least one of claims 1 to 5, characterized in that polyethylene naphthalate is used as the polyalkylene naphthalate.

7. A method for producing an amorphous plate according to at least one of claims 1-6, characterized in that the polyalkylene naphthalate is melted in the extruder, the melt is shaped by a nozzle and then calibrated, smoothed and cooled in the smoothing unit with at least two rollers before one brings the plate to size.

8. The method according to claim 7, characterized in that melting the polyalkylene naphthalate together with the soluble dye, the colorant and / or the UV stabilizer.

9. The method according to claim 7 or 8, characterized in that the polyalkylene naphthalate is dried before it is melted in the extruder.

10. The method according to at least one of claims 7 to 9, characterized in that ais used as polyalkylene naphthalate polyethylene naphthalate (PEN).

11. The method according to claim 10, characterized in that the temperature of the PEN melt is in the range of 250 to 320 ° C.

12. The method according to claim 10 or 11, characterized in that the first roller of the smoothing unit has a temperature which is in the range of 50 to 80 ° C.