DE102006025481A1 - Process for the preparation of a colored film of thermoplastics, film and use of the film - Google Patents

Abstract

The invention relates to a method for producing a colored film of thermoplastic material, wherein the thermoplastic material on an extrusion line, comprising an extruder, an extrusion die with an outlet opening in slot shape and a tempered roll (chill-roll roll) attached to a roll mill is, is melted and conveyed and emerges in the form of a flat colored melt web from the outlet opening of the extrusion die, the dyed melt web is applied to the tempered roll (chill-roll roll) and cooled, characterized in that the tempered roll (chill roll -Walze) has a concentricity of ± 10 microns or less and the mean distance between the outlet opening of the extrusion die and the tempered roller (chill-roll roller) in the operating state varies by no more than ± 25 microns. The invention further relates to the colored film itself and its uses as a colored film for data carriers.

Description

The invention relates to a method for producing a colored, optically isotropic film made of thermoplastic materials, the film itself and the use of the film as a cover film in optical data carriers, such as the Blu-ray Disc ^® and the disk equipped therewith.

State of the art

EP 1 117 731 B1 describes optically nearly isotropic polycarbonate films and a chill-roll process for their preparation. The films consist of linear or branched polycarbonate having an average molecular weight M _w of 10,000 to 40,000. Inventive films can, for. B. a shrinkage of <1% / <1% (190 ° C / 30 min machine-direction (MD) / Traverse-direction (TD)) have. The film according to the invention preferably does not have a deflection of linearly polarized light of greater than 2 angular minutes in any area of the surface. The path difference can z. B. 31 nm, the birefringence delta n 4 × 10 ^-4 . In the tensile test z. B. an elongation at break according to ISO 527-3 MD / TD of 39 and 35% measured. In order to avoid nozzle lines or extrusion strips, it is recommended to use an extrusion die whose inside surface in the die lip area has a roughness depth in accordance with DIN 4768 of 0.025 to 0.002. This can be achieved by chrome plating and polishing.

EP 1 285 742 A2 describes films for optical applications in the thickness range below 100 microns with a low phase difference of not more than 10 nm, an "optical axis deviation" of +/- 10 angular minutes and small thickness variations in the range of a maximum of 2.4 microns per 2 cm in width The films are produced by means of a chill-roll process, the favorable properties of the material being able to be achieved, in particular, by increasing the temperature of the polymer melt after leaving the extrusion die to at least 30 ° C. above contact with the chill-roll roll For this purpose, the path from the exit of the extrusion die and the touchdown point on the chill-roll roll can be chosen to be relatively short, for example in the range of, for example, 30 to 150 mm. The outgoing melt film can also be thermally shielded or additionally heated by means of an enclosure The method is suitable for a large number of Ku nststoffen, in particular for norbornene plastics.

US 5,476,134 describes chromium nitride coated extruders for the production of parts from aluminum-iron alloys. These are particularly suitable for reducing the erosion of the extruded parts in the production of aluminum alloys with low proportions of iron below 0.3%.

EP 351 886 (Bayer AG) describes a casting or extrusion process for the production of optically uniaxial, birefringent polycarbonate films, which are heated by means of a Quarzheizstrahlers. This achieves a reduction of the unwanted birefringence to no longer disturbing values.

JP 8336883 describes a process for the extrusion of thermoplastic films using an extrusion die wherein the edges of the exit orifice have a radius of 30 microns or less with an unevenness of not more than +/- 20%. The nozzle geometry described counteracts in particular the formation of undesirable deposits.

JP 6335949 describes a process for the extrusion of films of thermoplastic material, preferably z. As polyethersulfones, polyphenylene oxides or polyether ketones, wherein an extrusion die is used, wherein the edges of the outlet opening have a radius of 30 microns or less at a non-uniformity of not more than +/- 20. The extrusion die can be made of steel or ceramic. Coatings with chromium, nickel, titanium, copper, zinc, etc. can counteract possible interactions of the nozzle material with the extruded plastic materials. The nozzle geometry described counteracts in particular the formation of nozzle lines.

JP 2002-028941 describes a process for the production of films of polyvinyl alcohol used as polarizing films can. Films with reduced thickness variations can be obtained if an extrusion nozzle is used, in which the edges of the outlet opening a Radius of 200 μm or less.

JP 2003-267758 describes a process for coating optical fibers with a plastic coating. In this case, an extrusion die is used, in which the edges of the outlet opening have a radius of 10 to 30 microns. The nozzle geometry described in particular affects the formation of Plastic deposit in the area of the nozzle edge, so that the process can now be operated trouble-free over a longer production period. Another advantage is that the plastic coating has lower thickness variations.

EP 0 547 562 A1 describes a method for coating a unspecified flat web, which is transported deflected over a roller, wherein in the deflection region, an extrudate is applied from a slot extrusion nozzle. In order to advantageously influence the reproducibility and accuracy of the method, a distance measurement is installed to the right and left of the extrusion nozzle with a control loop. If the distance between the outlet opening of the extrusion nozzle and the roller deviates from a desired value, the position of the extrusion nozzle is correspondingly corrected by means of a servomotor.

EP 1 202 261 A1 Among others, the vertical birefringence of commercially available, extruded, chill-rolled polycarbonate films and commercial cast polycarbonate films is compared. The extruded films have vertical birefringence values of 0.00029, the cast films values of 0.00066.

EP 1 327 978 (Lintec, Sony) describes a transparent cover sheet for optical media that is weather resistant. The cover film consists of a binder layer of acrylic polymers and the actual protective layer of polyolefins or polycarbonates.

DE 102 0050 204 24 describes a process for producing a thermoplastic film, the film and the use of the film. The film consists of transparent polycarbonates having a thickness of 10 .mu.m to 150 .mu.m and an in-plane birefringence, which causes a vertical path difference of at most 25 nm when irradiated vertically, characterized in that the film in any area of the surface, based on a circular area with a diameter of 12 cm, a deflection of a perpendicularly incident light beam of greater than 0.8 angular minutes and a vertical birefringence of at most 0.0004. The film has a thickness tolerance, based on a circular area with a diameter of 12 cm, of not more than +/- 1%.

The "White Paper Blu-Ray Disc", 4th Edition published in November 2005, describes the physical requirements for the Blu-ray ^Disc® . The reflectance of the BD-ROM is set to 35% to 70% for the recording layer of a single layer BD.

Task and solution

A Range of application areas for Plastic films, in particular in the field of films for use as cover sheets for optical data carriers, require in addition to a low optical birefringence and beside an improved surface quality of the films and smaller thickness tolerances, more and more attractive features (optical eye-catcher effects) for markets such as Film industry and video game industry.

EP 1 117 731 B1 and EP 1 285 742 A2 disclose remarkable solutions for the production of films with extremely low birefringence properties in the range of a few nanometers, which meet high requirements in the optical field. In the surface properties can according to the doctrine of EP 1 117 731 B1 Produced films that have a deflection of linearly polarized light greater than 2 angular minutes in any area of the surface. According to the EP 1 285 742 A2 Thickness tolerances in the range of about 2.4 microns per 2 cm in width can be realized. The European patent applications describe transparent, undyed films, colorations are not described.

It has been seen as an object to provide a film of plastic, which has an extremely good birefringence in the field of EP 1 117 731 B1 or the EP 1 285 742 A2 On the other hand, it has a further improved surface quality and, in particular, even lower thickness tolerances over the entire film range and, moreover, it can be dyed without impairing the outstanding optical properties. The thickness tolerances should in particular meet high requirements for optical data carriers and should therefore refer to a specification within a circular area with a diameter of 12 cm. The use of dyes must under no circumstances impair the good optical properties.

The task is solved by a
A process for producing a film of colored thermoplastic material, wherein the thermoplasti plastic on an extrusion line, comprising an extruder, an extrusion die with an outlet opening in slot shape and a tempered roll (chill-roll roll), melted and conveyed and emerges in the form of a flat melt web from the outlet opening of the extrusion die, the melt web to the tempered roller (chill-roll roller) is applied and cooled,
characterized in that
the tempered roller (chill-roll roller) has a concentricity of +/- 10 microns or less and the mean distance between the outlet opening extrusion die and the tempered roller (chill-roll roller) in the operating state by not more than +/- 25 μm varies over time.

To the method according to the invention is a colored Film made of a thermoplastic material with a thickness of 10 μm to 150 μm and an in-plane birefringence when viewed vertically caused an optical retardation of at most 15 nm, as well a vertical birefringence of not more than 0.0004, can be produced or available, characterized in that the Film in any area of the surface a deflection of a vertical incident light of greater than an angular minute and a thickness tolerance relative to a circular area having a diameter of 12 cm of not more than +/- 1%.

One Advantage of the film according to the invention is that with their small lot sizes in comparison for the spincoating process when applying thin, transparent layers on disk easier to realize.

One Another advantage of the film of the invention is that it is possible over a exclusive coloring with a certain color mixture of the film according to the invention for certain Provide customers with a certificate of authenticity and origin. This Proof of authenticity is without additional Aids for to recognize everyone simply by inspection, by measurement the spectrum, you can analyze the slide more closely at any time, if the circumstances should require. The function of exclusive coloring is comparable to that of a hologram. The advantage of this proof of authenticity is that the colored Slide over the entire disk extends and not like a sticker that carries the hologram in one separate operation must be applied. The foil can not without destruction from the disk solved become.

Embodiment of the invention

method

Essential to the invention is the use of the chill-roll melt casting process, as has long been known (see, for example, US Pat. EP 1 117 731 B1 or EP 1 285 742 A2 ). In this case, a melt film emerging from an extrusion die is applied to a single cooling roll, the chill-roll roll, and cooled. Particularly preferably, the melt film should not or only slightly, not more than a factor of 5 be stretched in the extrusion direction and be exposed to any active cooling before it impinges on the chill-roll roll. This has the advantage that hardly any molecular orientations occur and the resulting film has a high degree of optical isotropy. The chill-roll process differs in particular from the so-called calendering processes, in which the melt film passes through a nip formed by two opposing rolls.

The The invention relates to a process for the preparation of the colored film according to the invention.

Of the thermoplastic colored Plastic is on an extrusion line with an extruder, a melt pump and an extrusion die with an outlet opening melted in slot shape, promoted and in the form of a flat melt web from the outlet the extrusion nozzle pushed out.

The coloring of the thermoplastic material can with all the usual Methods are done. Preference is given to the use of a masterbatch, i.e. a premix of the plastic to be extruded with the dye to be used, wherein the dye concentration higher in the master batch as in the final inked Plastic film is.

Prefers is a melt filter between the melt pump and the extrusion die provided, which holds back impurities. The mesh size of the filter insert can z. B. 5 microns up to 50 μm, preferably z. B. 10 microns up to 30 μm be.

The extrusion die can continue in the nozzle exit region in a conventional manner with a Profile tool. The profile tool is used for fine adjustment of the exiting colored melt profile by a thin-walled designed exit area under pressure of actuators, eg. As bolts, expansion bolts or piezotranslators, is deformed accordingly. Suitable is z. Example, the execution of the nozzle exit region as a flexible lip or as a so-called "superflex lip" (see, for example, EP-A 367 022) or as a membrane (see, Gross et al., Plastics 84 (1994) 10, pp 1352-1358).

The colored Melt web is fed to a single cooled roll, called a Chill-roll roller applied and cooled. The chill-roll roller can while z. B. have a temperature of 100 ° C to 200 ° C, preferably from 100 ° C to 130 ° C.

Avoidance of vibration transmission

The Advantages of the chill-roll process in producing a low oriented colored Film stands opposite as a significant disadvantage that the achievable thickness tolerances both in, as well as transversely to the extrusion direction significantly worse than in the calendering process. In the calendering process forms in the process the nip a small supply of melt. This stock and the Pressure in the nip lead to a homogenization of the Film thickness in all directions.

Due to the principle are thus the thickness tolerances usually achievable in the chill-roll process much worse.

Of the The invention is based on the finding that from the area of the extruder and in particular the melt pump vibrations transmitted to the extrusion die can be. These vibrations lead in the operating state to varying distances between the outlet opening of the extrusion die and the chill-roll roller. The varying distances in turn lead to compression or dilations of the colored ones Melt web, which in turn leads to an increase in thickness tolerances leads.

Of the Invention is further based on the finding that the chill-roll roll due to its own imbalance at varying distances between the outlet of the extrusion die and the chill-roll roll contributes. The varying distances to lead in turn to upsets or elongations of the colored melt web, which in turn leads to an increase in thickness tolerances.

It Therefore, according to the invention is an extrusion plant used or used in which the cooled roll (chill-roll roll) a concentricity of +/- 10 μm or less, preferably from +/- 5 μm or below, and the mean distance between the outlet opening of the extrusion die and the cooled Roller (chill-roll roller) in the operating state by not more than +/- 25 microns, preferably not more than +/- 15 μm, especially preferably changed by not more than +/- 10 microns. These activities lead to reduced thickness tolerances and improved surface quality of the resulting inked Films.

For the purpose The invention suitable temperable rollers (chill-roll roller) with a True running accuracy of +/- 10 μm or less, preferably from +/- 5 microns can in This accuracy can be made and are available from manufacturers of Share for Extrusion lines available. The specified concentricity refers to the built-in State or to the operating state. The roller must therefore both accurately manufactured and with high accuracy in the extrusion line be positioned and centered.

Of the mean distance or the respective minimum distance between the outlet opening the extrusion nozzle and the cooled Roller can z. B. by means of optical measuring sensors or by Laserwegemessung practically between any chosen measuring points be determined. It does not depend on the distance itself, but on the temporal variation of the distance. Appropriately, the mean distance is determined by two temperature-independent distance sensors measured, each to the right and left of the outlet of the extrusion die are positioned so that they from there, preferably the shortest distance or the shortest distances can capture the tempered roller.

The Limitation of the temporal variation or change of the mean distance between the outlet extrusion die and the tempered roller (chill-roll roller) in the operating state can be achieved in different ways.

A technical measure may be, the roll mill holding the tempered roll (chill-roll roll), at one or more points z. B. via braces, z. B. made of steel, fixed to the Ex Truss nozzle, z. B. by screwing or riveting to connect. By this simple measure, the average distance between the outlet opening extrusion nozzle and the cooled roller negative impacting vibrations are already significantly reduced.

A further technical measure may be the roll mill that holds the chilled roll (chill-roll roll), with the extrusion nozzle over at least to connect two actuators, the actuators via a Control circuit are controlled so that they actively change the distance between the outlet the extrusion nozzle and counteract the tempered roller. By this measure are the mean distance between the outlet opening of the extrusion die and the tempered roller negatively affecting vibrations again further reduced. The actuators, z. B. piezo actuators, can z. B. installed right and left of the tempered roller and at points to the right and left of the exit opening of the extrusion die be connected with this. It may possibly also additional fixed braces between the roller mill and the extrusion die attached become.

melt pump

One some effect, although not within the scope of the previously described Activities, can additionally be achieved when the extrusion line between the extruder and the extrusion die has a melt pump. The melt pump causes a leveling the otherwise fluctuating melt pressure from the extruder into the extrusion die in and carry so also to reduce vibration transmission at.

Prefers an extrusion plant is used in which the melt pump from the extrusion nozzle to Avoidance of vibration transmission is decoupled. The decoupling can be done mechanically, z. B. over flexible, high-temperature resistant lines for the colored melt.

A Reduction or avoidance of vibration transmission from the melt pump on the extrusion nozzle has the advantage that colored films obtained with further reduced thickness tolerances and improved surface quality can be.

Edge radius of the outlet opening of extrusion die

One Another feature, which in a preferred embodiment to low thickness tolerances the films of the invention can contribute, the radius of the edges of the outlet opening of the Extrusion nozzle of at the most 50 μm, preferred from at most or smaller than 30 μm, in particular of at most or less than 25 μm. The radii of the edges of the outlet opening of the extrusion nozzle point preferably over the width of the outlet opening an unevenness from at most or less +/- 5% on. The comparatively sharp and very even edges to lead probably to a particularly good detachment of the melt web, what the Preservation of films with low thickness tolerances can contribute. Preferably, the edge or both edges of the outlet opening has a Angle from 45 to 100 °, usually from 90 ° up.

The roughness of the inner surface of the die lip area can affect the surface quality of the films produced. The inner surface of the die lip area is the area behind the distribution channel and an optional jam island. Depending on the nature of the extrusion nozzle, the inner surface of the die lip region extends approximately 0.5 cm to 5 cm from the outlet opening into the interior of the extrusion die. The inner surface of the die lip region should preferably have roughness R _a to DIN 4768 of 0.01 microns to 0.002 microns or less, R _z of 0.08 microns to 0.015 microns and R _max 0.10 microns to 0.025 microns.

Friction reducing coatings

Prefers is the inner surface of the nozzle lip area the extrusion nozzle equipped with a friction-reducing coating. This has the advantage that the Process safety, especially in long-term operation is increased. After prolonged operation the extrusion system, for. B. after 20 to 60 hours of continuous operation, can unwanted Deposits in the nozzle lip area train, the nozzle lines on the film surface can cause. these can decisively diminished or even completely avoided, if the inner surface of the nozzle lip area the extrusion nozzle equipped with a friction-reducing coating. To the elasticity of the nozzle lip area not to impair the coating should not be too thick. Cheap are coatings with a total thickness in the range of 10 microns to 30 microns, preferably from 15 microns to 25 microns.

Of the Lip area of the nozzle is preferably divided into separable elements and thus allows a better accessibility when working on the inner surface.

The preferred roughness depth range can be achieved by polishing or by coating the inner surface of the die lip area. According to the EP 1 117 731 B1 For example, the inner surface of the die lip region may be z. B. be equipped with a chrome plating, which can be additionally polished.

The coating may preferably consist of Ni, CrN, TiCN, TiC, TiAlN, DLC (diamond-like carbon) or another diamond-like carbon coating. These coatings have over a chromium coating as in the EP 1 117 731 B1 described, the advantage of higher, up to ten times longer service life. Corresponding coatings and their application to steel surfaces are known in the art in principle, for. B. off US 5,476,134 or US 4,637,477 ,

A suitable method for applying a corresponding coating to the inner surface of the die lip area is z. B. the "physical vapor deposition" method (PVD method, see B. US 5,476,134 or US 4,637,477 ). The coating can be carried out on one or preferably several layers. In the multi-layer coating can preferably on the relatively soft steel or the steel alloy of the extrusion die, first a hard layer, for. B. a 10 microns to 20 microns thick layer of nickel are applied, which then with an even harder layer, for. B. a 2 microns to 5 microns thick layer TiN, CrN or DLC is coated. A multilayer coating of the inner surface of the inner nickel layer and a layer of TiN, CrN or DLC applied thereon is particularly advantageous for the extrusion of polycarbonate films.

The inner surface the extrusion nozzle in the extrusion die lip area may be metallurgically or chemically altered or doped.

The inner surface the extrusion nozzle in the extrusion die lip area can with a single or multi-layer coating of a fluorine compound be provided.

Heating of the exiting inked melt film

Prefers is the colored Melt web on the way between the exit from the extrusion die and the Touching point heated on the chill-roll roller. This has the advantage that inner molecular stresses only occur diminished. Cheap is it, the colored ones To heat the melt path so that they are in or just before the touchdown on the chill-roll roll a temperature of at least 30 ° C, at least 40 ° C, at least 50 ° C, at least 60 ° C or at least 80 ° C has above the glass transition temperature of the extruded plastic.

By glass temperature is meant in particular the midpoint temperature T _mg according to ISO 11357-2, point 3.3.3. The measurement is carried out without addition of plasticizer, with residual monomer contents (REMO) of less than 100 ppm, at a heating rate of 10 ° C / min and under a nitrogen atmosphere.

Enclosure / inert gas atmosphere

Prefers an extrusion plant is used or used in which the colored Melt web between the exit from the extrusion die and the Placement point on the chill-roll roller surrounded by an enclosure is. this makes possible on the one hand an effective heating of the colored melt web and opened at the same time the possibility, the colored ones Melt web on the way between the exit from the extrusion die and the Aufsetzpunkt on the chill-roll roll with an inert gas, z. B. Nitrogen, to surround. The latter has the advantage that oxidation processes in the plastic material and in the dye that is too unwanted discoloration or cloudiness to lead can, be reduced or avoided.

The dyed foil

The Invention relates to a colored Film made of a thermoplastic material with a thickness of 10 μm to 150 μm, preferably 20 microns up to 120 μm, in particular 30 microns up to 100 μm.

In-plane birefringence

The in-plane birefringence of the colored film is determined by the optical Aisle calculated. The optical path difference due to the birefringence of a, with respect to the film surface perpendicular incident light beam z. B. according to the principle of polarization microscopy (polarimeter) can be determined. The method is familiar to the person skilled in the art (see, for example, ISO 11455).

The colored Film has a birefringence (in-plane birefringence), the with vertical transmission an optical path difference of at the most 15 nm, preferably at most 5 nm, he can z. B. 2 nm to 10 nm or 2 nm to 5 nm. colorized Films with these values are considered optically and mechanically isotropic or near isotropic and are suitable for optical applications with high requirements.

Vertical birefringence

The colored extruded film according to the invention differs, among other things, from cast films (see, for example, US Pat. EP 351 886 ) by a significantly lower vertical birefringence (see for example EP 1 202 261 A1 ). The vertical birefringence of the colored film according to the invention is at most 0.0004, preferably at most 0.0003. A suitable measurement method for determining the vertical birefringence is z. B. in detail in EP 1 202 261 A1 , P. 11, line 44-S.12, line 24. The principle is based on a light incidence angle of 45 °, in contrast to the in-plane birefringence measurement.

One low value in the vertical birefringence is in particular advantageous if the colored film according to the invention used in optical data carriers becomes. The higher the numerical aperture of the laser optics for scanning the data carrier, the more is larger the proportion of oblique incident laser radiation. Especially for optics with high Numerical aperture will increase the signal-to-noise ratio with increasing vertical Birefringence worse.

surface quality

The colored film does not have a deflection of a vertically incident light beam of greater than in any area of the surface, based on a circular area with a diameter of 12 cm, preferably based on an area of 1 m ² , more preferably based on an area of 10 m ² as an angular minute, preferably not more than 0.5 angular minutes.

The measurement takes place by means of the registration of the deflection angle, which is experienced by a laser beam of about 100 μm diameter, which penetrates the colored foil. For this purpose, the so-called laser deflection method is used. Over the entire extrusion width, the angular deviation is measured by means of a moving table operated with a stepping motor, which is experienced by a laser beam of about 100 μm in diameter when the colored foil is irradiated vertically. In order to verify the required surface quality of the colored film according to the invention, punched pieces with a circular area with a diameter of 12 cm or sections or sections of the film web of 1 or 10 m ^{2 can be} measured.

thickness tolerance

The colored In particular, foil has a thickness tolerance or differences in the thickness of the film, based on a circular area with a diameter of 12 cm, of not more than +/- 1%, preferably not more than +/- 0.5% on. The percentage deviation refers to the mean of the maximum and minimum thickness values within the circular area a diameter of 12 cm. This specification ensures that the Film z. For example the production of optical data storage with high storage density from Z. B. 25 gigabytes (GB) or more is suitable. Related to one 100 μm thick colored Film is the thickness deviation from the mean value therefore no more than +/- 1 μm within a circular one area with a diameter of 12 cm.

The Determining the thickness tolerance can be achieved by interferometric layer thickness measurement be determined, which is known in the art.

For the interferometric Layer thickness measurement can, for. B. an achromatic measuring head can be used. The layer thickness measurement is based on the superposition of the at both interfaces of colored foil reflected light. With known refractive index of the material can determined from the spectrum of the reflected light, the layer thickness become.

plastics

The colored film consists of a thermoplastic, preferably of transparent thermoplastic material. Preferably, the non-colored film has a light transmittance for daylight (standard illuminant D65) τ _D65 sz B. DIN 5033/5036 in the range of at least 60%, preferably from 65 to 92%.

The colored Slide can z. B. of polymethyl methacrylate plastic, impact modified Polymethyl methacrylate, polycarbonate plastic, polystyrene plastic, Styrene-acrylonitrile plastic, polyethylene terephthalate plastic, glycol-modified Polyethylene terephthalate plastic, polyvinyl chloride plastic, polyolefin plastic, Cycloolefinic copolymers (COC), PPS plastic or PPSU plastic, Acrylonitrile-butadiene-styrene (ABS) plastic or blends consist of various thermoplastic materials.

The colored Foil preferably consists of a linear or branched polycarbonate with a weight average molecular weight Mw of 10,000 to 45,000, preferably from 12,000 to 25,000, more preferably consists of 15,000 to 20,000.

The molecular weight M _w (weight average) can be determined, for example, by gel permeation chromatography or by scattered light method (see, for example, BHF Mark et al., Encyclopaedia of Polymer Science and Engineering, 2nd Edition, Vol , 1989).

The dyes

When Dyes can all dyes that are compatible with polycarbonates and are very good can be used.

Especially For example, dyes from Clariant (Sandoplast Dyes such as Orange 3G, Red PFS, Red Violet R, Blue 2B, Green G) or equivalent, for example Dyes of the company Ciba.

Especially Dyes of Clariant (Sandoplast) are preferably used.

uses

The colored foil according to the invention can z. B. for the construction of transparent, colored layers in optical Media, as colored Cover film of optical data carriers, as a colored cover for scratch protection of optical data carriers, as dyed carrier material for the Information layer of optical data carriers or as colored functional Film used in liquid crystal displays become. Next, the film as authenticity or proof of origin be used. For this purpose, it is colored individually.

EXAMPLES

Process for the production the dyed foil

manufacturing a colored film according to the invention by chill-roll extrusion a colored polycarbonate molding compound with an average molecular weight Mw (weight average) of approx. 20,000 (daltons).

The Extrusion plant consists of a single-screw extruder, a melt pump and a slot extrusion die with an exit port of 680 mm × 0.4 mm. The slot extrusion nozzle is designed as a superflex lip (see EP-A 367 022).

The inner surface the extrusion nozzle in the lip area is polished, so that a roughness Ra of 0.002 microns, Rz of 0.015 μm and Rmax of 0.025 μm is reached. The inner surface the extrusion die is with a duplex coating of 15 μm Nickel and 5 μm CrN provided.

Of the Radius of the nozzle lip in the exit area is between about 100 and 200 microns and has a radius uniformity of +/- 50 microns over the Width.

At a distance of 25 mm from the outlet opening of the slot extrusion die is a chill-roll roll positioned in the middle. The roller has a diameter of 400 mm and a width of 700 mm. The roll surface has a roughness Ra <= 0.003 μm, and Rmax <0.25 μm measured according to DIN 4768. The roller has a concentricity <= 3 μm.

The extrusion die is with the roller mill at two points to the right and left of the outlet opening of the extrusion nozzle on steel profile carrier with a cross section of 5 cm × 1 cm firmly connected.

The Temperature of the chill-roll roller is set between 100 ° C and 130 ° C, preferably 110 ° C up to 120 ° C.

The Temperature of the colored Melting current is about 240 ° C. The dyed Melt film lays down approximately tangential to the roll surface and wraps around the roller by about 180 ° C.

The Distance between the exit of the colored melt from the nozzle and the Anchor point to the chill roller is housed, the internal temperature is about 120 ° C. This enclosure can be heated or under a protective gas atmosphere, e.g. heated and filtered (clean room class 100) nitrogen, be filled.

To Wrap the other rolls is the thickness of the dyed film web by a traversing arranged, non-contact measuring system determined and electronically processed information the Melt distribution of the nozzle by means of a Dehnbolzensystems over the width regulated.

Example 1: reference pattern made of polycarbonates without coloring

• Examples 2, 3 and 4 are with Clariant Sandoplast Blue 2B been prepared
• Examples 5 and 6 are made with Clariant Sandoplast Green G. been
• Examples 7 and 8 are made with Clariant Sandoplast Red PFS been

The relevant measured variables of In the examples 1 to 8 obtained dyed films are based on punched circular colored Patches with a diameter of 12 cm and are the following table summarized.

Claims (31)

Colored film of a thermoplastic material with a thickness of 10 to 150 .mu.m as a colored cover sheet in optical data carriers, as a colored cover for scratch protection of optical data carriers or as a colored carrier material for the information layer of optical data carriers, characterized in that the film has a coloring and the light transmission (in the wavelength range from 385 nm to 425 nm) after double penetration of the film thickness is between 35% and 90%. colorized Film according to claim 1, characterized in that light transmission (in the wavelength range from 385 nm to 425 nm) after double penetration of the film thickness between 50% and 90%. colorized Film according to claim 1, characterized in that light transmission (in the wavelength range from 385 nm to 425 nm) after double penetration of the film thickness between 70% and 90%. colorized A film according to claim 1, characterized in that the colored film an in-plane birefringence when viewed vertically caused an optical retardation of at most 25 nm. colorized A film according to claim 4, characterized in that the colored film an in-plane birefringence when viewed vertically caused an optical retardation of at most 15 nm Colored foil according to Claim 4, characterized in that the colored foil has an in-plane birefringence which, when irradiated vertically, has an optical path difference of at most 10 nm caused colorized A film according to claim 1, characterized in that the colored film a thickness tolerance, based on a circular area with has a diameter of 12 cm, of not more than +/- 2%. colorized A film according to claim 1, characterized in that the colored film a thickness tolerance, based on a circular area with having a diameter of 12 cm, of not more than +/- 1%. colorized A film according to claim 1, characterized in that the colored film a thickness tolerance, based on a circular area with a diameter of 12 cm, of not more than +/- 0.5%. colorized Film according to claim 1, characterized in that in no Area of the surface of the inked Foil, based on a circular area with a diameter of 12 cm, a deflection of a vertically incident light beam from bigger than 0.8 angular minutes and a vertical birefringence of at most Has 0.0004. colorized Film according to claim 1, characterized in that it consists of Polymethyl methacrylate plastic, impact modified polymethyl methacrylate, Polycarbonate plastic, polystyrene plastic, styrene-acrylonitrile plastic, Polyethylene terephthalate plastic, glycol-modified polyethylene terephthalate plastic, Polyvinyl chloride plastic, Polyolefin plastic, cycloolefinic copolymers (COC), PPS plastic or PPSU plastic, Acrylonitrile-butadiene-styrene (ABS) plastic or mixtures (blends) consists of various thermoplastic materials. Colored foil according to one or more of Claims 1 to 12, characterized in that it consists of a linear or branched polycarbonate having an average molecular weight M _{w of} from 10,000 to 45,000. Use of the colored film according to one of previous claims as a cover film in optical data carriers. Use of the colored film according to claims 1 to 12 as a cover for scratch protection of optical data carriers. Use of the film dyed according to claims 1 to 12 as a carrier material for the Information layer of optical data carriers. Process for producing a colored film, characterized in that in a first step from a colored master batch and the Plastic or Kunststoffgemsich a colored granules produces and then extruded. Process for the preparation of a colored film made of thermoplastic material, wherein the colored thermoplastic Plastic on an extrusion line, containing an extruder, an extrusion die with an outlet opening in slot-shape and a tempered roller (chill-roll roller), the at one Roller mill is attached, melted and conveyed and in the form of a flat Melt web from the outlet opening the extrusion nozzle emerges, the melt web applied to the tempered roll (chill-roll roll) and cooled Is, characterized in that the tempered roller (chill-roll roller) a concentricity of +/- 10 μm or less has and the mean distance between the outlet opening extrusion die and the tempered roller (chill-roll roller) varies by no more than +/- 25 μm in the operating state. Method according to claim 16, characterized in that that the tempered roller (chill-roll roller) attached to a roller mill that's with the extrusion die is firmly connected. Method according to claim 16 or 17, characterized that the tempered roller (chill-roll roller) attached to a roller mill is that with the extrusion nozzle over at least two actuators is connected, the actuators via a Control circuit are controlled so that they change the distance between the outlet the extrusion nozzle and the cooled Counteract roller actively. Method according to one or more of claims 16 to 19, characterized in that the Edges of the outlet opening the extrusion nozzle a radius of at most 50 μm at an unevenness of not more than +/- 5% exhibit. Method according to one or more of claims 16 to 21, characterized in that the Extrusion line between the extruder and the extrusion die one Has melt pump. Method according to one or more of claims 16 to 21, characterized in that the inner surface of the nozzle lip area the extrusion nozzle equipped with a friction-reducing coating. Method according to claim 22, characterized in that that the Coating of a single or multi-layer, optionally modified Coating of Ni, CrN, TiCN, TiC, TiAlN, DLC or a diamond-like Carbon coating exists. Method according to claim 22 or 23, characterized that the inner surface the extrusion nozzle in the extrusion die lip area metallurgically or chemically altered or is doped. Method according to Claim 24, characterized that the inner surface the extrusion nozzle in the Extrusion die lip area with a single or multi-layer coating of a fluorine compound is provided. Method according to one or more of claims 16 to 25, characterized in that the colored Melt web on the way between the exit from the extrusion die and the Touchdown point is heated on the chill-roll roller. Method according to one or more of claims 16 to 26, characterized in that a Extrusion plant is used, in which the dyed melt web between the exit from the extrusion nozzle and the attachment point the chill-roll roll is surrounded by an enclosure. Method according to Claim 27, characterized that the colored Melt web on the way between the exit from the extrusion die and the Touch-down point on the chill-roll roll surrounded by an inert gas becomes. Process according to one or more of Claims 16 to 29, characterized in that the inner surface of the die lip region has roughnesses R _a to DIN 4768 of 0.01 μm to 0.002 μm or below, R _z of 0.08 μm to 0.015 μm and R _max 0.10 μm to 0.025 μm. disk, characterized in that associated with a film according to any one of the preceding claims is. disk, characterized in that associated with a film with an individual coloring.