KR20000064699A - Amorphous Plates of Crystalline Polyalkylenenaphthalates - Google Patents

Abstract

The present invention relates to an amorphous plate-like article characterized in that the thickness is 1 to 20mm and the main component is at least one polyalkylene naphthalate. The present invention also relates to a method for producing the plate-like article.

Description

Amorphous plates of crystalline polyalkylene naphthalates

The present invention relates to at least one crystalline polyalkylene naphthalate amorphous sheet having a thickness in the range of 1 to 20 mm. The sheet has excellent optical and mechanical properties. The invention also relates to a method of making the sheet.

Amorphous sheets having a thickness of 1 to 20 mm are well known. These sheet-like structures are made of amorphous amorphous thermoplastics. Typical examples of thermoplastics processed into such sheets are polyvinyl chloride (PVC), polycarbonate (PC) and polymethyl methacrylate (PMMA). These semifinished products are produced in so-called extrusion lines (PolymerWerkstoffe [Polymericmaterials], Volume II, Technology 1, p. 136, georg Thieme Verlag, Stuttgart, 1984). Powdery or granular crude material is melted in an extruder. After extrusion, the amorphous thermoplastic material can easily be reshaped through polishing stacks or other forming dies, resulting in a constant increase in viscosity as the temperature decreases. After molding, the amorphous thermoplastic material has a high viscosity such that it can be " self settled " in a suitable stability, ie sizing die. However, they are still soft enough to be shaped by the die. The melt viscosity and internal stiffness of the amorphous thermoplastics in the sizing die are so high that the semi-finished product does not collapse before cooling in the sizing die. For example, in the case of materials that are easily decomposed, such as PVC, certain processing aids are required during extrusion, such as, for example, processing stabilizers for degradation and lubricants for unadjustable heat due to too high internal friction. External lubricants are essential to prevent material from sticking to walls and rolls.

For PMMA processing, for example, a devolatilizing extruder is used to remove moisture.

In the production of amorphous thermoplastic sheets, sometimes expensive additives may be needed, which in some cases may migrate and evaporate causing surface deposit problems on semi-finished products. PVC sheets are difficult to recycle or can only be recycled by special neutralization or electrolysis processes. PC and PMMA sheets are likewise difficult to recycle and can only be recycled with loss of mechanical properties or extreme degradation.

In addition to these disadvantages, PMMA sheets are also extremely poor in impact strength and split under fracture or mechanical stress. In addition, since PMMA sheets are combustible like wood, they cannot be used, for example, for interior use and for decorative structures.

PMMA and PC sheets also cannot be molded under cooling. During room temperature molding, the PMMA sheet is broken into dangerous pieces. During normal temperature molding of the PC sheet, hairy cracks and white crushing occur.

EP-A-0 471 528 describes a method of forming a product from a polyethylene terephthalate (PET) sheet. The PET sheet is heat treated on both sides in the thermoforming mold in the temperature range between the glass transition temperature and the melting point. The molded PET sheet is removed from the mold when the degree of crystallization of the molded PET sheet is in the range of 25 to 50%. The thickness of the PET sheet described in EP-A-0 471 528 is 1 to 10 mm. The thermoformed article made from the PET sheet is partially crystalline and therefore no longer transparent and the surface properties of the molded article are determined by the thermoforming method and the temperature and shape presented by it, and the optical properties of the PET sheet used (eg For example, polishing degree, clouding and light transmission) are not important. In general, the optical properties of these sheets are poor and need to be optimized.

US-A-3,496,143 describes a vacuum thermoforming method of 3 mm thick PET sheets, which has a crystallization range of 5 to 25%. The crystallinity of the thermoformed molded article is at least 25%. Also for these PET sheets, it is not necessary to impose requirements on the optical properties. Since the crystallinity of the sheets used is already 5 to 25%, these sheets are cloudy and not transparent.

It is an object of the present invention to provide an amorphous sheet having both excellent mechanical and optical properties and having a thickness of 1 to 20 mm.

Good optical properties are, for example, high light transmittance, high surface polishing, extremely low haze and high transparency, depending on the embodiment.

Good mechanical properties are high impact strength and high breaking strength.

In addition, the sheet according to the present invention should be recyclable, in particular without losing mechanical properties, and with low flammability, for example for interior use and decorative structures.

This object is achieved by an amorphous sheet having a thickness of 1 to 20 mm, containing at least one crystalline polyalkylene naphthalate as a main component.

The amorphous sheet contains at least one crystalline polyalkylene naphthalate as a main component. Polyethylene naphthalate, polypropylene naphthalate and polybutylene naphthalate are preferred, and polyethylene naphthalate (PEN) is particularly preferred.

The amorphous sheet of the invention can be transparent, can be colored transparently or can be colored opaque.

In a transparent embodiment, the surface polishing degree (measurement angle 20 °) of the amorphous sheet measured according to DIN 67530 is 110 or more, preferably 120 or more. The light transmittance measured according to ASTM D 1003 is at least 80%, preferably at least 82%, and likewise the haze of the sheet measured according to ASTM D 1003 is less than 15%, preferably less than 11%.

The transparency of the transparent sheet, measured at an angle of less than 2.5 ° (ASTM D 1001), is preferably at least 90%, particularly preferably at least 92%.

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

Soluble dye refers to a substance dissolved molecularly in a polymer (DIN 55949).

Color change as the amorphous sheet is colored is based on wavelength-dependent absorbance and / or light scattering. Since a constant minimum particle size is a physical requirement for scattering, the dye should only be able to absorb without scattering light.

Coloring with a dye is a dissolution process. As a result of this dissolution process, the dye is dissolved in molecular units, for example, in a PEN polymer. Such dyes are referred to as transparent or translucent or opalescent.

From various classes of soluble dyes, fatty- and aromatic-soluble dyes are particularly preferably provided. These are for example azo and anthraquinone dyes. They are particularly suitable for dyeing PEN because of the high glass transition temperature of PEN and the limited migration of dyes (see J. Koerner: Soluble dyes in the plastics industry in "VDI-Gesellschaft Kunststofftechnik: Einfarben von Kuststoffen, VDI) Verlag, Dusseldorf 1975).

Examples of suitable soluble dyes are: Solvent Yellow 93, pyrazolone derivatives, Solvent Yellow 16, oil soluble azo dyes, Fluorolgreen-Gold, fluorescent polycyclic dyes, Solvent Red 1, azo dyes, azodais, eg thermoplastics Red BS, Sudan Red BB, Solvent Red 138, anthraquinone derivatives, fluorescent benzopyran dyes such as Fluorol RedgK and Fluorol OrangegK, Solvent Blue 35, anthraquinone dyes, Solvent Blue, phthalocyanine dyes and the like. Mixtures of two or more of these soluble dyes are also suitable.

According to the invention, soluble dyes can be pre-added to the desired concentration by the raw material supplier or can be added to the extruder during sheet production.

However, dye additives are particularly preferably added via masterbatch techniques. The soluble salts are completely dispersed and / or dissolved in the solid carrier material. Suitable carrier materials are certain resins, polyalkylene naphthalates themselves or other polymers that are sufficiently compatible with polyalkylene naphthalates.

The particle size and bulk density of the masterbatch are similar to those of the polyalkylene naphthalate, allowing for a homogeneous distribution and thus homogeneous and transparent coloring.

The surface polishing degree of the transparently colored sheet measured according to DIN 67530 (measuring angle 20 °) is 100 or more, preferably 110 or more, and the range of light transmittance measured according to ASTM D 1003 is 5 to 80%, Preferably it is 10 to 70%, and the haze range of the sheet measured according to ASTM D 1003 is 2 to 40%, Preferably it is 3 to 35%.

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

When considering colorants, dyes and pigments are distinguished according to DIN 55944. The pigment is substantially insoluble in the polymer under the respective processing conditions, while the dye is soluble (DIN 55949). The coloring action of the pigment is caused by the particles themselves. Pigments are generally associated with particle sizes of 0.01 μm to 1.0 μm. According to DIN 53206, the definition of pigment particles distinguishes initial particles, aggregates and agglomerates.

Early particles, as generally produced synthetically, tend to aggregate as a result of their extremely small particle size. Local aggregation of the initial particles produces an agglomerate, which has a smaller surface area than corresponding to the sum of the surface areas of the initial particles. As agglomerates of initial particles and / or aggregates in the corners and ends, agglomerates are formed, the total surface area of which differs only slightly from the sum of the respective areas. When referring to the pigment particle size without a more detailed indication, this refers to the aggregates which are essentially present after implantation.

In powdered pigments, agglomerates always form with the formation of agglomerates, which disintegrate during the coloring process and must be wetted and homogeneously distributed by the polymer. These simultaneous processes are called dispersion. On the other hand, in the case of coloring with a dye, the related process is one of the dissolution processes, and as a result, the salt channel exists in a dissolved form in molecular units.

In contrast to inorganic pigments, there is no complete insolubility in the case of certain organic pigments, and especially in the case of pigments of simple composition having a small molecular weight.

Dyes are suitably described by their chemical structures. However, pigments in each case of the same chemical composition can be present by making them by different crystal modification methods. A typical example thereof is a white pigment, titanium dioxide, which may be present in the rutile and apyramidal forms.

In the case of pigments, the utility can be improved by coating, ie by post-treating the surface of the pigment particles with an organic or inorganic agent. Such an improvement is particularly helpful in facilitating dispersion and improving light stability and weather resistance and chemical resistance. Representative coating agents for pigments are, for example, fatty acids, fatty acid amides, siloxanes and aluminum oxides.

Examples of suitable inorganic pigments are the white pigments titanium dioxide, zinc sulfide and tin sulfide, which may be coated with organic and / or inorganic materials.

Titanium dioxide particles may comprise anatase or rutile, but preferably comprise rutile, which is greater in opacity than anatase. In a preferred embodiment, at least 95% by weight of the titanium dioxide particles are rutile. These can be prepared by conventional processes, for example by chlorinated or sulfided processes. The average particle size is relatively low and the range of 0.10 to 0.30 μm is preferred.

By using titanium dioxide of the above type, no vacuoles are formed in the polymer matrix during the production of the sheet.

Titanium dioxide particles may have a coating of an inorganic oxide commonly used as a coating or coating composition for TiO ₂ white pigments in paper, thereby improving light fastness. TiO ₂ is known to be photoactive. Under the action of UV rays, free radicals form on the particle surface. These free radicals migrate to the film-forming component of the coating composition, causing the reactants to degrade and yellow. Particularly suitable oxides are oxides of aluminum, silicon, zinc or magnesium, or mixtures of two or more of these compounds are described, for example, in EP-A-0 044 515 and EP-A 0 078 633. The coating may also include organic compounds having polar and nonpolar groups. During the preparation of the sheet by extrusion of the polymer melt, the organic compound should have sufficient thermal stability. Examples of polar groups are -OH, -OR, -COOX (X = R, H or Na, R = alkyl having 1 to 34 carbon atoms). Preferred organic compounds are alkanols and fatty acids having 8 to 30 carbon atoms in the alkyl group, especially fatty acids and primary n-alkanols having 12 to 24 carbon atoms, and also polydiorganosiloxanes and / or polyorganohydridesiloxanes, eg For example polydimethylsiloxane and polymethylhydridesiloxane.

The coating on titanium dioxide particles usually consists of from 1 to 12 g of inorganic oxide, in particular from 2 to 6 g and from 0.5 to 3 g of organic compound, in particular from 0.7 to 1.5 g, based on 100 g of titanium dioxide particles. The coating is preferably applied to the particles in an aqueous suspension. Inorganic oxides are precipitated in aqueous suspensions from water soluble compounds, for example alkali metal aluminates, in particular sodium aluminate, aluminum hydroxide, aluminum sulfate, aluminum nitrate, water silicate or silicic acid.

The term inorganic oxides, such as Al ₂ O ₃ and SiO ₂ , are also understood to include hydroxides or their various dehydration steps, for example oxide hydrates, although their exact composition and structure are not known. For example, oxide hydrates of aluminum and / or silicon are precipitated on TiO ₂ pigments after sintering and polishing in an aqueous suspension, after which the pigments are washed and dried. The precipitation can thus take place directly in suspension as prepared by a synthetic process and then sintered and subsequently wet polished. Precipitation of oxides and / or oxide hydrates of the respective metals takes place from water-soluble metal salts within a known pH range, in the case of aluminum, for example using aluminum sulphate (less than pH 4) in an aqueous solution, pH 5-9, preferably Preferably, an aqueous ammonia or sodium hydroxide solution in the range of 7 to 8.5 is added to precipitate the oxide hydrate. Starting from waterglass or alkali metal aluminate solutions, the pH of the initially charged TiO ₂ suspension should be in the strong alkaline range (pH 8 or higher). In this case, precipitation occurs by adding an inorganic acid, such as sulfuric acid, in the pH range 5-8. After the metal oxide has precipitated, the suspension is continuously stirred for 15 minutes to about 2 hours, at which time the precipitated coating is aged. The coated product is separated from the aqueous dispersion and after washing, it is dried at elevated temperature, in particular 70-110 ° C.

Typical inorganic black pigments are carbon black modifiers, which differ from carbon black pigments in that they have a higher ash content and black oxide pigments such as iron oxide black and copper, chromium and iron oxide mixtures (mixed phase pigments) as well. Can be coated.

Suitable inorganic colored pigments are colored oxide pigments, hydroxyl-containing pigments, yellowing pigments and chromates.

Examples of colored oxide pigments include iron oxide red, titanium dioxide-nickel oxide-antimony oxide mixed phase pigments, titanium dioxide-chromium oxide-antimony oxide mixed phase pigments, mixtures of iron, zinc and titanium oxides, chromium iron oxide brown, systems Spinel of cobalt-aluminum-titanium-nickel-zinc oxide, and other mixed phase pigments based on metal oxides.

An example of a typical hydroxyl-containing pigment is an oxide hydroxide of trivalent iron such as FeOOH.

Examples of yellow pigments include cadmium sulfide selenide in the form of lattice, cadmium-zinc sulfide, sulfur containing sodium aluminum silicate bonded polysulfide-style in the lattice.

Examples of chromates are lead chromates, which may exist in monoclinic, tetragonal and tetragonal crystalline forms.

The color pigments can all be uncoated or coated with inorganic and / or organic materials, similar to both white and black pigments.

Organic color pigments are generally divided into azo pigments and so-called bizo pigments.

A characteristic aspect of the azo pigment is the azo group (-N = N-). Azo pigments include monoazo pigments, diazo pigments, diazo condensation pigments, salts of anzo dye acids and mixtures of azo pigments.

The amorphous colored sheet contains at least one of inorganic and / or organic pigments. In certain embodiments the amorphous sheet may also contain mixtures of inorganic and / or organic pigments, and also soluble dyes. The concentration of the soluble dye in the present invention is preferably 0.01 to 20% by weight, particularly preferably 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) may already be added at the desired concentration by the raw-materials manufacturer or may be added to the extruder during sheet production.

However, it is particularly preferred that the color additive (s) be added via masterbatch technology or through a solid-pigment preparation. Organic and / or inorganic pigments and, optionally, soluble dyes are fully dispersed in the solid carrier material. Suitable carriers are polymers that color certain resins, by themselves or otherwise with other polymers that are sufficiently compatible with the polyalkylene naphthalate.

It is important that the particle size and density of the solid-pigment formulations and master batches are similar to those of the polyalkylene naphthalate, so that they can be distributed homogeneously and thus colored.

The surface polishing degree of the colored sheet, measured according to DIN 67530 (measurement angle 20 °), is preferably 90 or more, and the light transmittance measured according to ASTM D 1003 is preferably less than 5%.

The colored sheet is also opaque and has homogeneous optical properties.

In a further preferred embodiment, the amorphous sheet also contains at least one of the UV stabilizers as light stabilizer, the concentration of the UV stabilizer being preferably 0.01 to 5% by weight, based on the weight of the polyalkylene naphthalate to be.

The ultraviolet region of light, in particular the ultraviolet region, ie the wavelength range of 280 to 400 nm, initiates the decomposition process in the thermoplastic material, which not only changes the visible appearance due to color change or yellowing as a result of whitening, but also mechanical-physical properties It is badly affected.

Because these photochemical decomposition processes dramatically limit the possible uses of many thermoplastics, it is of great importance industrially and economically to inhibit them.

Polyalkylene naphthalates, for example, begin to absorb UV light even below 360 nm and their absorbances increase significantly below 320 nm and are very pronounced below 300 nm. Maximum absorbance is from 280 to 300 nm.

In the presence of oxygen, mainly chain splitting is observed and no crosslinking is observed. Carbon monoxide, carbon dioxide and carboxylic acids are the main photoacidification products in terms of quantity. In addition to the direct photolysis of ester groups, oxidation reactions that similarly form carbon dioxide via peroxide radicals should also be considered.

The photooxidation reaction of polyalkylene naphthalate can also produce peroxides and their decomposition products and cause related chain decomposition reactions through the decomposition of hydrogen in the α-position of the ester group (see H. Day, DMWiles: J. Appl.Polym. Sci 16, 1972, p. 203).

UV light stabilizers or UV absorbers as light stabilizers are chemical compounds that can mediate the physical and chemical processes of photo-induced decomposition reactions. Carbon black and other pigments may have a partial light protective effect. However, these materials are not suitable for transparent sheets because they discolor or cause a change in color. Only organic and organometallic compounds which give no color to the thermoplastics to be stabilized or only give very little color or only slight color changes are suitable for transparent amorphous sheets.

Examples of suitable UV stabilizers as light stabilizers include 2-hydroxybenzophenone, 2-hydroxybenzotriazole, organonickel compounds, salicylic acid esters, cinnamic acid ester derivatives, resorcinol monobenzoate, oxalic acid anhydride, hydride Hydroxybenzoic acid esters, steric hindered amines and triazines, with 2-hydroxybenzotriazoles and triazines being preferred.

In a particularly preferred embodiment, the amorphous sheet according to the invention comprises, as main components, crystalline polyethylene naphthalate and 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) 0.01-5.0 wt% of oxy-phenol or 2,2'-methylene-bis (6-2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) -phenol 0.01- 5.0 weight%. In a preferred embodiment, it is also possible to use mixtures of these two UV stabilizers or mixtures of at least one of these two UV stabilizers with other UV stabilizers, the total concentration of the light stabilizers being crystalline polyethylene naphthalate 0.01 to 5.0% by weight is preferred based on the weight of.

According to the invention, crystalline polyalkylene naphthalate is understood in the following meanings:

Crystalline polyalkylene naphthalate homopolymers,

Crystalline polyalkylene naphthalate copolymers,

Crystalline polyalkylene naphthalate compound materials,

Crystalline polyalkylene naphthalate regenerating materials and

Other variants of crystalline polyalkylene naphthalates.

Preferred copolymers and compound materials in the present invention are mixtures of polyalkylene naphthalates and polyalkylene terephthalates, in particular mixtures of polyethylene naphthalate (PEN) and polyethylene terephthalate (PET).

The amorphous sheet in the present invention is preferably understood to mean an amorphous sheet, although the crystallinity of the crystalline thermoplastics used is preferably 10% to 65%. Amorphous, ie essentially amorphous, crystallinity is generally at most 5%, preferably at most 2%, particularly preferably at 0%.

In addition, the possibility of good room temperature shaping without cracks, hair cracks and / or white cracks is surprisingly found so that the sheet according to the invention can be molded and bent without the action of temperature.

In addition, the measurements indicate that the polyalkylene naphthalate sheet according to the invention is of low flammability and flammability, for example suitable for interior use and decorative structures.

The sheet according to the invention can also be recycled without problems, without pollution of the environment and loss of mechanical properties, which means that it is suitable for use as short term advertising signs or other advertisements, for example.

In a particularly preferred embodiment, the amorphous sheet according to the invention contains, as a main component, crystalline polyethylene naphthalate.

In the case of polyethylene naphthalate, it is preferable that no crack occurs on the sheet during the measurement of Charpy impact strength a _n (measured according to ISO 179 / 1D). In addition, the range of Izod notched impact strength _ak (measured according to ISO 180 / 1A) of the sheet is preferably 2.0 to 12.0 kJ / m 2, particularly preferably 3.0 to 8.0 kJ / m 2.

The microcrystalline melting point T _m measured by DSC (differential scanning calorimetry) at a heating rate of 10 ° C./min is 240 to 300 ° C., preferably 250 to 290 ° C., and the crystallization temperature T _c measured according to DIN 53479 is 100 to Polyethylene naphthalate, having a glass transition temperature T _g of 100 to 140 ° C. and a density of 1.3 to 1.45 g / cm 3, is a preferred polymer as a starting material for sheet production of the present invention.

The standard viscosity SV (DCA) 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.

Intrinsic viscosity IV (DCA) is calculated from the standard viscosity SV (DCA) as follows:

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

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

The polydispersity m _w / M _n of the polyethylene naphthalate, measured using GPC, is preferably 1.5 to 4.0, in particular 2.0 to 3.5.

The production of the amorphous sheet according to the invention can be carried out by extrusion process, for example in an extrusion line.

1 is a diagram of an extrusion line for producing an amorphous sheet of the present invention.

Such an extrusion line is shown in schematic form in FIG. 1, which is essentially

An extruder (1) as a plasticizing unit,

Slot die (2) as a die for molding;

A polishing stack / calender 3 as a sizing die,

Post-cooling cooling bed 4 and / or roller conveyor 5,

-Removal rolls (6),

-Separation saw (7),

An end trimming device 9 and optionally

A stacking device (8).

The process comprises the steps of drying the polyalkylene naphthalate, optionally if necessary, melting it in an extruder with soluble dyes, colorants and / or UV stabilizers, extruding the melt through a die and Sizing, polishing and cooling in the polishing stack prior to cutting the sheet to size.

Soluble dyes, colorants and / or UV stabilizers are preferably added via masterbatch techniques. In this case, the soluble dyes, colorants and / or UV stabilizers are fully dispersed in the solid carrier material. Suitable carrier materials are certain resins, polyalkylene naphthalates themselves, or other polymers that are sufficiently compatible with polyalkylene naphthalates otherwise.

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

PEN is preferably dried at 160-180 ° C. for 4-6 hours before extruding.

PEN and, optionally, additive masterbatch are melted in an extruder. The melting temperature range of the PEN is preferably 250 to 320 ° C., which is possible if the temperature of the melt is essentially determined by both the temperature of the extruder and the residence time of the melt in the extruder.

The melt is then released from the extruder through a die. The die is preferably a slot die.

The PEN melted by the extruder and shaped by the slot die is sized with a polishing calender roll, i.e. reliably cooled and polished. The calender rolls can be arranged, for example, in I-, F-, L- or S-shape.

The PEN material is then post-cooled on a roller conveyor, trimmed to size at the end, cut to length and finally loaded.

The thickness of the PEN sheet is essentially determined by the take-off located on the cooling (polishing) roll, which is the end of the cooling zone, coupled to it in terms of speed, and on the one hand the conveying speed and the distance between the rolls on the other do.

Both single and twin screw extruders can be used as the extruder.

The slot die preferably includes a restrictor rod for regulating flow rate through the removable die body, ribs and width. In this case, the adjusting rod can be bent with tension and pressure screws. The thickness is set by adjusting the lip. It is important to ensure that the PEN granules have a uniform temperature because the PEN melt flows at different thicknesses resulting in different flow paths.

The sizing die, ie the polishing calendar, provides the shape and dimensions to the PEN melt. This is accomplished by cooling below the glass transition temperature using a cooling and polishing machine. Since no surface defects are formed in the cooled state, molding should no longer occur at this stage. For this reason, it is desirable to drive the calender rolls together. To avoid sticking of the PEN melt, the temperature of the calender roll should be lower than the microcrystalline melting temperature. The PEN melt leaves the slot die having a temperature of 240 to 300 ° C. The temperature of the first polishing / cooling roll is 50 to 80 ° C. depending on the discharge and sheet thickness. A second, slight chiller roll cools the second or other surface.

While the sizing device freezes the PEN surface as smoothly as possible and cools the profile to a dimensionally stable degree, the aftercooling device lowers the temperature of the PEN sheet substantially to room temperature. Aftercooling can occur on roller boards. The removal rate must be precisely matched with the speed of the calender roll to avoid defects and thickness variations.

As a further device, the extrusion line for making PEN sheets may comprise a separating saw, end trimmer, loading unit and adjustment station as a device for cutting to length. End or edge trimmers are advantageous because under certain circumstances the thickness of the edge region may not be uniform. The thickness and visible properties of the sheet are measured at the adjusting station.

Due to the surprisingly large number of excellent properties, the amorphous polyalkylene naphthalate sheets according to the invention are used in a number of different applications, for example for interior panels, decorative structures and decorative products, displays, signs, machinery and automobiles. Particularly suitable for protective glazes, for lighting sectors, for shop fitting and shelving, for advertisements, menu stands, basketball backboards, interior partitions and also for external use, for example as glass substitutes.

The present invention is described in more detail below by way of examples, but is not limited thereto.

Measurement of each property is performed according to the following standards or techniques.

<Measurement>

Surface Polishing Degree:

Surface polishing is measured according to DIN 67 530. The reflection value is measured as an optical variable for the sheet surface. According to the standards ASTM-D 523-78 and ISO 2813, the angle of incidence is fixed at 20 °. Under a fixed angle of incidence, the light strikes the plane and thereby reflects or scatters. Incident light on the photoreceptor is represented by a proportional electrical figure. The measurement has no magnitude and should be mentioned with the angle of incidence.

Light transmittance:

Light transmittance refers to the ratio of the total amount of transmitted light and the amount of incident light.

Light transmittance is measured with a "Hazeguard plus" measuring device according to ASTM 1003.

Haze and transparency:

Haze is the percentage of transmitted light that deviates from the incident light bundle by more than 2.5 ° on average. Transparency is measured at an angle of less than 2.5 °.

Haze and transparency are measured using a "Hazeguard plus" measuring device according to ASTM 1003.

Whiteness:

Whiteness was measured using an electronic attenuation photometer from Zeiss, Oberkochem (DE), and whiteness was defined by Equation 2 using a standard light source C, 2 ° normal observer.

WG = RY + 3RZ-3RX

Where RG = whiteness, RY, RZ, RX = Y, Z, and the corresponding reflection factor when using a color measurement filter. The white standard used is compression molding formed from barium sulfate (DIN 5033, Part 9).

Surface defects:

Surface defects are measured visually.

Charpy Impact Strength a _n :

This value is measured according to ISO 179/1 D.

Izod notched impact strength a _k :

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

density:

Density is measured according to DIN 53479.

SV (DCA), IV (DCA):

Standard viscosity SV (DCA) is determined in dichloroacetic acid according to DIN 53726.

Intrinsic viscosity (IV) is calculated from the following equation (1) from the standard viscosity (SV).

Equation 1

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

Thermal properties:

Thermal properties such as the microcrystalline melting point T _m , the crystallization temperature range T _c , the post- (cold) crystallization temperature T _CN and the glass transition temperature T _g are measured using a differential scanning calorimeter (DSC) at a heating rate of 10 ° C./min. do.

Molecular Weight, Polydispersity:

The molecular weights m _w and m _n and the resulting polydispersity m _w / M _n are determined using gel permeation chromatography (g).

Weather Resistance (Double Sided), UV Stability:

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

Test Device: Atlas Ci 65 Weather Ometer

Test conditions: ISO 4892, i.e. simulating climate

Survey time: 1000 hours (per face)

Probe: 05W / ㎡, 340nm

Temperature: 63 ℃

Relative atmospheric humidity: 50%

Xenon lamps: internal and external filters of boron silicate

Irradiation cycle: 102 min UV light, followed by 18 min UV light with water spraying the specimen, followed by 102 min UV light.

Color change:

After exposure to artificial outside air the color change of the sample is measured using a spectrophotometer according to DIN 5033.

The meaning of the symbols is as follows:

ΔL: luminance difference

+ ΔL: Sample is brighter than standard.

-L: The sample is darker than the standard value.

ΔA: difference in red-green region

+ ΔA: The sample is more red than the standard value.

-A: The sample is greener than the standard value.

ΔB: difference in blue-yellow region

+ ΔB: The sample is more yellow than the standard value.

-ΔB: The sample is bluer than the standard value.

ΔE: Overall color change

△ E = √ △ L ² + △ A ² + △ B ²

The larger the numerical deviation from the standard value, the larger the color difference.

A value of ≤0.3 is negligible and means no significant color change.

Yellow figures:

The yellow value g is measured according to DIN 6167 as a deviation from the colorlessness towards the "yellow" side. A yellowness g value of ≤ 5 is visually unperceptible.

In the following and comparative examples, the sheet is the case where the monolayer, opaque colored sheets of different thicknesses produced on the described extrusion lines are used.

Example 1

From this the polyethylene naphthalate producing a transparent sheet has a standard viscosity SV (DCA) of 810, which corresponds to an intrinsic viscosity IV (DCA) of 0.65 dl / g. The moisture content is 15% and the crystalline melting point according to the DSC measurement is 270 ° C. The polydispersity m _w / M _n of polyethylene naphthalate is 2.14. The glass transition temperature is 119 ° C.

Prior to extrusion, polyethylene naphthalate is dried in a dryer for 5 hours at 170 ° C. and then extruded into a single screw extruder through a flat calendered flat film die with a wall in S-shape at an extrusion temperature of 286 ° C., evenly thickened. A sheet of 2 mm is obtained. The temperature of the first calender roll is 65 ° C, and the temperature of each subsequent roll is 58 ° C. The removal rate and the speed of the calender roll are 4.0 m / min.

After cooling, a 2 mm thick transparent PEN sheet was trimmed at the end and cut and loaded to length using a separating saw.

The characteristic profile of the produced transparent PEN sheet is as follows:

Thickness: 2mm

-Surface polishing degree first surface: 170

(Measurement angle 20 °) 2nd side: 165

-Light transmittance: 86%

Transparency: 98%

Haze: 1.5%

-Surface Defect / ㎡: None

(Speak, Orange-Skin, Bubble, etc.)

-Charpy impact strength a _n : No crack

-Room temperature molding possibility: Good, no defect

Crystallinity: 0%

Density: 1.31 g / ㎥

Example 2

Using a polyethylene naphthalate having the following properties, a transparent sheet was prepared similarly to Example 1:

SV (DCA): 1100

IV (DCA): 0.85 dl / g

Density: 1.32 g / cm 3

Crystallinity: 24%

Crystal phase melting point Tm: 254 ℃

Polydispersity m _w / M _n : 2.02

Glass transition temperature: 117 ℃

Extrusion temperature is 280 degreeC. The temperature of the first calender roll is 66 ° C., and the temperature of the subsequent roll is 60 ° C. The removal speed and the speed of the calender roll are 1.9 m / min.

The characteristic profile of the produced transparent PEN sheet is as follows:

Thickness: 6mm

Surface Polishing Degree, First Side: 172

(Measurement angle 20 °) Second Surface: 170

-Light transmittance: 88.1%

Transparency: 99.6%

Haze: 2.6%

-Surface Defect / ㎡: None

(Speak, Orange-Skin, Bubble, etc.)

-Charpy impact strength a _n : No crack

-Room temperature molding possibility: Good, no defect

Crystallinity: 0%

Density: 1.32g / ㎥

Example 3

Similar to Example 2, a transparent sheet was prepared.

Extrusion temperature is 275 degreeC. The temperature of the first calender roll is 57 ° C, and the temperature of the subsequent roll is 50 ° C. The removal rate and the speed of the calender rolls are 1.7 m / min.

The characteristic profile of the produced transparent PEN sheet is as follows:

Thickness: 10㎜

Surface Polishing Degree, First Side: 151

(Measurement angle 20 °) Second Surface: 148

-Light transmittance: 86.5%

Transparency: 99.2%

Haze: 4.95%

-Surface Defect / ㎡: None

(Speak, Orange-Skin, Bubble, etc.)

-Charpy impact strength a _n : No crack

-Room temperature molding possibility: Good, no defect

Crystallinity: 0.1%

Density: 1.33g / ㎥

Example 4

Similar to Example 2, a transparent sheet was prepared. 70% polyethylene naphthalate from Example 2 is mixed with 30% recycled material made from the above polyethylene naphthalate.

The characteristic profile of the produced transparent PEN sheet is as follows:

Thickness: 6mm

Surface Polishing Degree, First Side: 168

(Measurement angle 20 °) 2nd side: 166

-Light transmittance: 87.3%

Transparency: 99.4%

Haze: 3.2%

-Surface Defect / ㎡: None

(Speak, Orange-Skin, Bubble, etc.)

-Charpy impact strength a _n : No crack

-Room temperature molding possibility: Good, no defect

Crystallinity: 0%

Density: 1.32g / ㎥

Example 5

6 mm thick, transparently colored, amorphous sheet containing polyethylene naphthalate from Example 2 and 2 wt% of an soluble dye Solvent Red 138, anthraquinone derivative from BASF® Thermoplastg To produce.

Soluble dye Solvent Red 128 is added in the form of a masterbatch. The masterbatch consists of 20% by weight of the dye Solvent Red 138 and 80% by weight of polyethylene naphthalate as described above. Prior to extrusion, 90% by weight polyethylene naphthalate and 10% by weight masterbatch were dried in a drier for 5 hours at 170 ° C. and then uniaxially through a flat calendered flat film die on which the walls were arranged in S-shape at extrusion temperature 280 ° C. Extrude with an extruder and make even to obtain a sheet having a thickness of 6 mm. The temperature of the first calender roll is 66 ° C and the temperature of each subsequent roll is 60 ° C. The removal speed and the speed of the calender roll are 2.9 m / min.

After cooling, a transparent colored PEN sheet 6 mm thick was trimmed at the end and cut and loaded to length using a separating saw.

The property profile of the produced transparent PEN sheet, colored transparently red, is as follows:

Thickness: 6mm

Surface Polishing Degree, First Side: 118

(Measurement angle 20 °) Second Surface: 115

-Light transmittance: 28.1%

Transparency: 97.1%

Haze: 9.6%

-Surface Defect / ㎡: None

(Speak, Orange-Skin, Bubble, etc.)

-Charpy impact strength a _n : No crack

-Room temperature molding possibility: Good, no defect

Crystallinity: 0%

Density: 1.34g / ㎥

Example 6

A white colored, amorphous sheet was produced, containing 3 weights of polyethylene naphthalate and 6% by weight of titanium dioxide from Example 2 as the main component.

Titanium dioxide is of rutile type and is coated with an inorganic coating of Al ₂ O ₃ and an organic coating of polydimethylsiloxane. The average particle diameter of titanium dioxide is 0.2 micrometer.

Titanium dioxide is added in the form of a silver masterbatch. The masterbatch consists of 30% by weight titanium dioxide and 70% by weight of polyethylene naphthalate as described above.

Prior to extrusion, 80% by weight polyethylene naphthalate and 20% by weight titanium dioxide masterbatch were dried in a drier at 170 ° C. for 5 hours and then at a extrusion temperature of 286 ° C., a flat calender flat film die with a wall arrayed in S-shape. Through a single screw extruder and evenly to obtain a sheet having a thickness of 3 mm. The temperature of the first calender roll is 73 ° C, and the temperature of each subsequent roll is 67 ° C. The removal rate and the speed of the calender roll are 6.5 m / min.

After cooling, the white colored PEN sheet having a thickness of 3 mm is trimmed at the end and cut into lengths using a separating saw and loaded.

The characteristic profile of the produced transparent PEN sheet, colored white, is as follows:

Thickness: 3mm

Surface Polishing Degree, First Side: 123

(Measurement angle 20 °) Second Surface: 122

-Light transmittance: 0%

Whiteness: 110

Color: White

-Surface Defect / ㎡: None

(Speak, Orange-Skin, Bubble, etc.)

-Charpy impact strength a _n : No crack

-Room temperature molding possibility: Good, no defect

Crystallinity: 0%

Example 7

Polyethylene naphthalate and UV stabilizer from Example 2 as main components, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) oxyphenol (registered trademark: Tinuvin 1577, Ciba-Geigy) A transparent amorphous sheet having a thickness of 3 mm, containing 1.0% by weight.

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

In order to obtain a homogeneous distribution, 1.0% by weight UV stabilizer is directly incorporated into polyethylene naphthalate by the raw material producer.

Prior to extrusion, polyethylene naphthalate is dried for 5 hours at 170 ° C. in a dryer and then extruded into a single screw extruder through a flat calendered flat film die with a wall arranged S-shaped at an extrusion temperature of 286 ° C., and made evenly thick. A sheet of 3 mm is obtained. The temperature of the first calender roll is 73 ° C, and the temperature of each subsequent roll is 67 ° C. The removal rate and the speed of the calender roll are 6.5 m / min.

After cooling, the transparent colored PEN sheet having a thickness of 3 mm is trimmed at the end and cut into lengths using a separating saw and loaded.

The characteristic profile of the produced transparent PEN sheet is as follows:

Thickness: 3mm

Surface Polishing Degree, First Side: 168

(Measurement angle 20 °) Second Surface: 161

-Light transmittance: 85%

Transparency: 97%

Haze: 1.8%

-Surface Defect / ㎡: None

(Speak, Orange-Skin, Bubble, etc.)

-Charpy impact strength a _n : No crack

-Room temperature molding possibility: Good, no defect

Crystallinity: 0%

Density: 1.33g / ㎥

After weathering for 1000 hours on each side using an Atlas Ci 65 Weather Ometer, the properties of the PEN sheet were as follows:

Thickness: 3mm

Surface Polishing Degree, First Side: 162

(Measurement angle 20 °) 2nd side: 153

-Light transmittance: 84.1%

Transparency: 96%

Haze: 2.0%

Overall Discoloration E: 0.22

Dark Discoloration △ L: -0.18

Red-Green Discoloration ΔA: -0.08

Blue-Yellow Discoloration ΔB: 0.10

-Surface defects

(Cracks, brittleness): none

Yellow value g: 4

-Charpy impact strength a _n : No crack

-Possibility of forming at room temperature: good

Claims (12)

An amorphous sheet having a thickness of 1 to 20 mm and containing at least one polyalkylene naphthalate as a main component. The sheet according to claim 1, which contains at least one dye soluble in polyalkylene naphthalate. The sheet according to claim 1 or 2, wherein the sheet contains at least one organic and / or inorganic pigment as a colorant. The sheet according to claim 1 or 3, wherein the sheet contains at least one UV stabilizer as the light stabilizer. The sheet according to any one of claims 1 to 4, wherein the polyalkylene naphthalate used is polyethylene naphthalate, polypropylene naphthalate and / or polybutylene naphthalate. The sheet according to any one of claims 1 to 5, wherein the polyalkylene naphthalate used is polyethylene naphthalate. Melting the polyalkylene naphthalate in an extruder, extruding the melt through a die, sizing it before cutting the sheet to size, and polishing and cooling with two or more rolls in a polishing stack The manufacturing method of the amorphous sheet in any one of Claims 1-6. 8. The process of claim 7, wherein the polyalkylene naphthalate is melted with soluble dyes, colorants and / or UV stabilizers. The process according to claim 7 or 8, wherein the polyalkylene naphthalate is dried before melting in the extruder. The process according to claim 7, wherein the polyalkylene naphthalate used is polyethylene naphthalate (PEN). The process of claim 10 wherein the temperature range of the PEN melt is 250 to 320 ° C. The method according to claim 10 or 11, wherein the temperature range of the first roll of the polishing stack is 50 to 80 ° C.