WO1999013019A1 - Procede de production de films minces a partir d'une dispersion non aqueuse et pigments a effet produits a partir de ces films et dont la coloration depend de l'angle d'observation - Google Patents

Procede de production de films minces a partir d'une dispersion non aqueuse et pigments a effet produits a partir de ces films et dont la coloration depend de l'angle d'observation Download PDF

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Publication number
WO1999013019A1
WO1999013019A1 PCT/EP1998/005420 EP9805420W WO9913019A1 WO 1999013019 A1 WO1999013019 A1 WO 1999013019A1 EP 9805420 W EP9805420 W EP 9805420W WO 9913019 A1 WO9913019 A1 WO 9913019A1
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polymer
cholesteric liquid
mol
film
aromatic
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PCT/EP1998/005420
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German (de)
English (en)
Inventor
Bernd Dewald
Andreas Stohr
Axel Schönfeld
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Clariant Gmbh
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Publication of WO1999013019A1 publication Critical patent/WO1999013019A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
    • C09B67/00—Influencing the physical, e.g. the dyeing or printing properties of dyestuffs without chemical reactions, e.g. by treating with solvents grinding or grinding assistants, coating of pigments or dyes; Process features in the making of dyestuff preparations; Dyestuff preparations of a special physical nature, e.g. tablets, films
    • C09B67/0098—Organic pigments exhibiting interference colours, e.g. nacrous pigments
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/36—Pearl essence, e.g. coatings containing platelet-like pigments for pearl lustre

Definitions

  • the invention relates to a process for the production of thin films and effect pigments made therefrom from thermoplastic cholesteric liquid crystal polymers (cLCPs) with optically variable properties.
  • cLCPs thermoplastic cholesteric liquid crystal polymers
  • Cholesteric main chain polymers are known and can be prepared analogously to nematic main chain polymers by using an additional chiral comonomer (US-A-4,412,059; EP-A-0 196 785; EP-A-0 608 991; EP-A-0 391 368) or by reacting nematic main chain polymers (LCP) with additional chiral comonomers (EP-A-0 283 273).
  • LCP nematic main chain polymers
  • EP-A-0 283 273 additional chiral comonomers
  • Cholesteric main chain polymers are characterized by their helical superstructure. On the one hand, this means that the material no longer has the anisotropy of mechanical properties that is customary in nematic liquid crystal polymers.
  • the material shows pronounced color effects, which are based on the selective reflection on the helical superstructure.
  • the exact reflection color depends on the viewing angle and above all on the pitch of the helix.
  • a vertical view of a specimen - a color with a wavelength that corresponds to the pitch of the helical superstructure appears as the reflection color. This means that the reflected light has a shorter wavelength, the smaller the pitch of the
  • Helix is.
  • the pitch of the helix that forms essentially depends on the proportion of the chiral comonomer, the type of incorporation into the polymer, the degree of polymerization and the structure of the chiral comonomer.
  • an absorbent, in particular black, background is generally necessary, since otherwise the non-selective part of the light is reflected on the background due to insufficient coverage of the cholesteric liquid crystals, which weakens the color impression .
  • Liquid crystal polymers are knife-coated onto a tape in the melt. After cooling, the thin films are e.g. separated from the belt by scrapers or by ultrasonic treatment and then broken into platelets.
  • the process described has the disadvantage that it can only be used with low-melting polymers with low melt viscosity. Effect pigments based on low-melting cholesteric liquid crystal polymers, however, show insufficient temperature stability in lacquer layers.
  • EP-A-0 601 483 describes a process by which a polyorganosiloxane is knife-coated and crosslinked at about 120 ° C. on a polyethylene terephthalate film. The mechanical separation of the film obtained from the film is achieved in that the film is guided over a small diameter deflection roller, the crosslinked material peeling off the carrier.
  • This document describes the knife application of a viscous liquid onto a carrier film and subsequent crosslinking to form a thin film. The process is not suitable for converting thermoplastic, solvent-insoluble cholesteric liquid crystal polymers into thin films.
  • the object of the present invention is to provide a method which avoids the disadvantages listed in the prior art, and to produce pigments dependent on the viewing angle, which have high temperature stability and high chemical resistance (insolubility).
  • this object can be achieved by applying a non-aqueous dispersion of a thermoplastic, cholesteric liquid-crystalline polymer to a planar substrate.
  • the present invention relates to a method for producing thin films of thermoplastic cholesteric liquid-crystalline polymers, characterized in that one or more thermoplastic cholesteric liquid-crystalline polymers are applied as a non-aqueous dispersion to a planar substrate and heated to or above the chiralization temperature.
  • polymer particles are dispersed in organic solvents and applied to a planar substrate with the desired layer thickness. After the applied dispersion has dried, the polymer layer is heated to or above the chiralization temperature.
  • Organic solvents in particular aliphatic hydrocarbons, such as hexane, heptane, cyclohexane, terpenes, liquid paraffins, oils, come as non-aqueous liquids which serve as the dispersion medium for the finely divided polymer particles; aromatic hydrocarbons, such as benzene, toluene,
  • Alcohols such as methanol, ethanol, isopropanol, butanol, octanol; Esters such as ethyl acetate, butyl acetate, amyl acetate, dioctyl phthalate; halogenated hydrocarbons such as chloroform, methylene chloride, perchlorethylene, trichlorethylene, chlorobenzene; Ketones such as methyl isobutyl ketone, methyl ethyl ketone, acetone, cyclohexanone, isophorone; and liquid polyhydroxy alcohols, such as
  • Ethylene glycol, propylene glycol, glycerin and polyethylene glycol are considered.
  • other additives in particular dispersing additives and thickeners, such as, for example, polyether compounds, as described in EP 0 359 034 B1, or organically soluble cellulose ethers or fatty acid alkanolamides can be used to prepare non-aqueous dispersions.
  • the added amounts of the other additives are between 0 to 5% by weight, in particular between 0.01 to 3% by weight, based on the total amount of the dispersion.
  • the non-aqueous dispersion can be prepared using all known dispersing and homogenizing units which are suitable for this purpose. Examples include dissolvers, Ultraturrax and agitator ball mills.
  • the aim is ad 50 value less than 30 ⁇ m, preferably less than 15 ⁇ m, in particular less than 10 ⁇ m.
  • the non-aqueous dispersion contains the thermoplastic cholesteric liquid crystal polymer in an amount of 5 to 60% by weight, in particular 10 to 50% by weight, based on the total weight of the dispersion.
  • the ground and sifted cholesteric liquid crystal polymer is dissolved in an organic solvent using a dissolver or Ultraturrax, optionally with the addition of a dispersing additive dispersed.
  • the dispersion is then applied to the carrier substrate using a doctor blade, dried and heated to the chiralization temperature.
  • the layer thickness can be achieved not only by varying the doctor blade gap, but also via the concentration of the dispersion. However, the layer thickness can also be adjusted using an air brush. Other methods of applying the non-aqueous dispersion to the substrate may also be mentioned, such as spraying, printing or rolling.
  • the substrate is coated not only on one side but on both sides.
  • the carrier substrate is to remain in the effect pigment, e.g. transparent particles (thin glass plates) or opaque particles, or a separation of the cLCP from the substrate on both sides is possible, e.g. by dissolving the
  • the thickness of the polymer layer after drying is normally between 1 and 100 ⁇ m, preferably between 1 and 25 ⁇ m, in particular between 3 and 15 ⁇ m.
  • Temperature-stable materials are suitable as planar carrier substrates for the process according to the invention. Temperature-stable polymer films or strips, metal foils or strips and glass plates or strips are preferably used. Polyimide films, cellulose films and
  • metal foils both pure metal foils and laminated metal foils can be used.
  • Leveling additives are polyacrylates and polyesters, some of which are based on
  • Silicon dioxide can be adsorbed, as in conventional
  • Powder coating systems are used.
  • Foil covered and rolled at the chiralization temperature Foil covered and rolled at the chiralization temperature.
  • the polymer films are preferably still removed after the cover film has been removed
  • All temperature-resistant polymer films or strips, as well as metal foils or strips, which may also have special coatings, are suitable as cover films for the rolling process.
  • Polyimide foils and silicone-coated aluminum foils are preferred.
  • the formation of the helical structure can also be promoted by substrates with polymeric layers, such as, for example, polyvinyl alcohol, cellulose derivatives or polyimides.
  • polymeric layers such as, for example, polyvinyl alcohol, cellulose derivatives or polyimides.
  • the orientation process of the polymer molecules can be positively influenced by electrical and magnetic fields.
  • thermoplastic cholesteric polymers which can be used according to the invention include both cholesteric liquid-crystalline main chain polymers, cholesteric liquid-crystalline side group polymers and combined liquid-crystalline main chain / side group polymers.
  • Cholesteric liquid-crystalline side group polymers are, for example, polysiloxanes, cyclic siloxanes, polyacrylates or polymethacrylates with mesogens in the side groups.
  • the mesogens in the side group are, for example, phenylbenzoates or biphenols substituted with cholesterol.
  • the main chain polymers are preferably liquid-crystalline polyesters, polyamides or polyesteramides, the aromatic and / or cycloaliphatic hydroxycarboxylic acids, aromatic aminocarboxylic acids; aromatic and / or cycloaliphatic dicarboxylic acids, and aromatic and / or cycloaliphatic diols and / or diamines; as well as chiral, bifunctional comonomers.
  • Cholesteric liquid-crystalline main chain polymers are generally produced from a chiral component and from hydroxycarboxylic acids and / or a combination of dicarboxylic acids and diols.
  • the polymers consist essentially of aromatic constituents.
  • aliphatic and cycloaliphatic components such as, for example, cyclohexanedicarboxylic acid.
  • Preferred cholesteric polymers for the purposes of the present invention are cholesteric liquid-crystalline main chain polymers consisting essentially of a) 0 to 99.8 mol% of one or more compounds from the group of aromatic hydroxycarboxylic acids, cycloaliphatic hydroxycarboxylic acids and aromatic aminocarboxylic acids; b) 0 to 50 mol% of one or more compounds from the group of aromatic dicarboxylic acids and cycloaliphatic dicarboxylic acids; c) 0 to 50 mol% of one or more compounds from the group of aromatic and cycloaliphatic diols and diamines; d) 0.1 to 40 mol%, preferably 1 to 25 mol%, of chiral, bifunctional
  • the polymers can Contain components with only one functional group or with more than two functional groups, such as dihydroxybenzoic acid, trihydroxybenzenes or trimellitic acid. In this way, the molecular weight of the polymers can be influenced.
  • the components with more than two functional groups act as a branching point in the
  • Polymer and may only be added in small concentrations, for example 0 to 5 mol%, if crosslinking of the material is to be avoided during the condensation.
  • Cholesteric main chain polymers which are built up from the following building blocks of the individual monomer groups are particularly preferred:
  • Aromatic hydroxycarboxylic acids, aminocarboxylic acids hydroxybenzoic acids, hydroxynaphthalenecarboxylic acids, hydroxybiphenylcarboxylic acids, aminobenzoic acids, hydroxycinnamic acids
  • Aromatic dicarboxylic acids aliphatic dicarboxylic acids, erephthalic acid, isophthalic acid, biphenyldicarboxylic acids, naphthalenedicarboxylic acids, cyclohexanedicarboxylic acids, pyridinedicarboxylic acids, diphenylether dicarboxylic acids, carboxycinnamic acids and
  • aromatic diols aminophenols, diamines: hydroquinones, dihydroxybiphenyls, tetramethyldihydroxybiphenyls, naphthalenediols, dihydroxydiphenylsulfones, diihydroxydiphenyl ethers, dihydroxyterphenyls,
  • R and R ' are each independently H, C ⁇ Ce alkyl or phenyl, preferably H or CH 3 .
  • sulfonic acid groups When using sulfonic acid groups as a functional group for condensation, it may be advantageous to use them in an activated form, for example as sulfochloride or as sulfonic acid ester.
  • polymer building blocks described can also contain further substituents, such as, for example, methyl, methoxy, cyano or halogen.
  • the polycondensation can be carried out by all customary methods. For example, melt condensation with acetic anhydride, which is described, for example, in EP-A-0 391 368, is suitable. Condensation with acetic anhydride is also possible in solution or in the disperse or emulsified phase.
  • the monomers are preferably linked via ester bonds (polyester), amide bonds (polyesteramide / polyamide) and / or via imide bonds (polyesterimide / polyimide), but the linkage can also take place via other known types of linkage.
  • Number of carboxyl groups corresponding number of hydroxyl groups be present.
  • targeted excesses of functional groups for example more carboxy groups than hydroxyl groups, can also be used in order to control the achievable molecular weight, for example.
  • carboxylic acids carboxylic acid derivatives such as acid chlorides or carboxylic acid esters can also be used.
  • carboxylic acid derivatives such as acid chlorides or carboxylic acid esters can also be used.
  • hydroxy components corresponding hydroxy derivatives, such as, for example, the acetylated hydroxy compounds, can also be used.
  • the cholesteric liquid-crystalline polymers can also contain crosslinkable groups, so that it is possible to fix an oriented liquid-crystal polymer by, for example, photo-crosslinking, which preferably takes place after extrusion.
  • the cLCPs have a very low solubility, so that their molecular weights cannot be determined using commercially customary methods (GPC, light scattering).
  • the intrinsic viscosity of the polymers in a solution of pentafluorophenol / hexafluoroisopropanol can be used as a measure of the molecular weight.
  • suitable Polymers with an intrinsic viscosity between 0.1 dl / g and 10 dl / g at a temperature of 25 ° C.
  • the cholesteric liquid crystal polymers described above can be used directly in the context of the invention. However, it is also possible to produce thermoplastic blends from the cholesteric liquid-crystalline polymers.
  • the blends can either consist of various thermoplastic cholesteric liquid-crystalline polymers, but it is also possible to mix the cholesteric liquid-crystalline polymers with cholesteric or nematic polymers.
  • thermoplastic cholesteric polymers it is also possible to mix the thermoplastic cholesteric polymers with colorants, it being possible to achieve special coloristic effects.
  • Colorants are understood here to mean both pigments and dyes.
  • the pigments can be inorganic or organic in nature. Examples of inorganic pigments are: titanium dioxide, iron oxides, mixed metal oxide pigments, cadmium sulfides, ultramarine blue or chromate molybdate pigments.
  • organic pigments all can be known to the person skilled in the art from the relevant literature, e.g. W. Herbst, K. Hunger, Industrial Organic Pigments, VCH Verlag, 1987, well-known pigments are used, e.g.
  • Suitable dyes are, for example, quinophthalene, perinone, anthraquinone, azomethine complex, azlactone and azo dyes. The dyes can be completely or partially dissolved in the cholesteric liquid crystal polymer.
  • the colored polymer contains 0.1 to 10% by weight of colorant.
  • leveling additives e.g. polyacrylates, polyesters
  • stabilizers e.g. UV or heat stabilizers, antioxidants
  • antistatic agents and optical brighteners in the cholesteric liquid crystal polymer
  • Colorants and / or auxiliaries and additives are mixed with the cholesteric liquid crystal polymer until a homogeneous distribution is obtained.
  • Mixing is most advantageously carried out in the melt of the cholesteric liquid crystal polymer.
  • Mixing can be carried out with all suitable mixing units, such as dispersion kneaders, ⁇ Banbury kneaders or screw kneaders, or by extrusion. In the case of extrusion in particular, a powdery mixture of the additives with the cholesteric liquid-crystalline polymer can also be assumed.
  • the colorant can also be added directly during the preparation of the cholesteric liquid-crystalline polymer, advantageously towards the end of the polycondensation reaction, preferably immediately before the finished polymer is discharged.
  • the colorant into the cholesteric liquid crystal polymer in the form of a master batch.
  • Synthetic and natural waxes, polymers and rubbers can be used as carriers for a masterbatch.
  • the preferred carrier for a masterbatch is the cholesteric liquid crystal polymer itself.
  • the masterbatch can contain a pigment or a dye or else a mixture of different pigments and / or dyes. You can also add more to the masterbatch Auxiliaries and / or additives are incorporated.
  • Such masterbatches can be produced by all known processes, for example by intimately mixing the colorants with the carrier in the melt in suitable mixing units, for example dispersion kneaders, Banbury kneaders or screw kneaders, for example twin-screw kneaders.
  • the cholesteric liquid-crystalline polymer can be colored with the masterbatch by mixing the two materials and then extruding them.
  • the masterbatch can also be metered in as a melt into the melt of the cholesteric liquid crystal polymer via a side extruder and / or a melt pump. The most economical way to do this is with
  • the colored liquid-crystalline polymers produced by the processes described above are normally in the form of a physical mixture
  • the present invention also relates to a process for the production of effect pigments, characterized in that, as described above, one or more thermoplastic cholesteric liquid-crystal polymers are processed as non-aqueous dispersion on a planar support substrate to give thin films, and then the liquid-crystalline polymer films are separated from the support substrate and the polymer films are brought into the platelet size and shape suitable for effect pigments.
  • Liquid crystal polymers are themselves unsuitable to use them according to the conventional processes, such as bubble extrusion or flat film extrusion, to produce thin films.
  • the special optical properties of the cholesteric liquid crystal polymers are only observed when the molecules form the helical structure at or above the chiralization temperature of the polymer.
  • the thermoplastic cholesteric liquid crystal polymers are therefore preferably processed into thin films at temperatures which are above the chiralization temperature and thus significantly above their melting temperatures.
  • the wavelength of the selective reflection of the cholesteric liquid crystal polymers used is determined by the pitch of the helical structure.
  • the pitch depends on the structure of the polymer, the melt viscosity, the presence of solvents and in particular on the twisting power of the chiral monomer ("helical twisting power"). It is also a function of the temperature.
  • the polymer film obtained according to the invention is separated from the carrier substrate.
  • the mechanical separation of the brittle cholesteric liquid crystal polymer from the base can e.g. in that the
  • Underlay is guided over a pulley with a small diameter. This causes the liquid crystal polymer to peel off the carrier film.
  • the flaking can be improved by using a liquid jet or by treatment in an ultrasonic bath. Any other method with which the liquid-crystalline polymer can be removed from the base is, however, also suitable.
  • the substrate is coated with a release layer which, as an intermediate layer between the cLCP and the substrate, facilitates the detachment of the cLCP from the substrate.
  • a release layer which, as an intermediate layer between the cLCP and the substrate, facilitates the detachment of the cLCP from the substrate.
  • a thin layer of a polymer that is soluble in water or in an organic solvent can serve as the release layer. It is about ensure that the melting and flow properties of the release layer polymers are matched to the chiralization temperature of the cLCP. Care must also be taken to ensure that the release layer is not destroyed when the non-aqueous dispersion is applied.
  • Water-soluble polymers are homo- and copolymers with water-soluble ones
  • the carrier material is dissolved.
  • the liquid-crystalline polymer film can be separated from the carrier foil by passing the tape into an acid or base bath after the baking process, the metal dissolving.
  • the liquid crystalline polymer flakes obtained can be brought to the desired particle size by grinding and / or sieving, a platelet-shaped geometry should be obtained, i.e. a platelet diameter that is at least twice, preferably at least three times, the platelet thickness.
  • the effect pigments In order to obtain an optimal color impression through selective reflection, the effect pigments must have a flat shape as flat as possible.
  • the thickness of such flake-like effect pigments is generally between 1 ⁇ m and 100 ⁇ m, preferably between 1 ⁇ m and 25 ⁇ m and in particular between 3 ⁇ m and 15 ⁇ m. Depending on the desired application, deviating layer thicknesses can also be appropriate.
  • Effect pigments with a color impression depending on the viewing angle can be used for coloring paints, cosmetics and as printing pigments, for example for security printing or decorative packaging printing. Paints which contain the effect pigments according to the invention can be used for painting natural and synthetic materials, for example wood, metal or glass, in particular the body or body parts of motor vehicles.
  • thermoplastic cholesteric liquid crystal polymers examples include thermoplastic cholesteric liquid crystal polymers
  • acetic anhydride 103 moles were added and flushed through with a gentle stream of nitrogen.
  • the mixture is heated to 140 ° C. with stirring in the course of 15 minutes and this temperature is maintained for 30 minutes.
  • the temperature is then raised to 325 ° C. in the course of 165 minutes and the melt is stirred further at this temperature for 30 minutes.
  • Acetic acid begins to distill off at approx. 220 ° C.
  • the nitrogen purge is then stopped and a vacuum is slowly applied.
  • the melt is stirred for a further 30 minutes under vacuum (approx. 5 mbar). It is then aerated with nitrogen and the polymer is discharged and pelletized using an extruder.
  • the polymer has a brilliant, reddish-yellow color that appears bluish green when viewed at an angle. The color already appears during the condensation in a vacuum and is retained after cooling.
  • Example B 30 moles of 2-hydroxy-6-naphthoic acid, 50 moles of 4-hydroxy-benzoic acid, 10 moles
  • Terephthalic acid 2 moles of 4,4'-dihydroxybiphenyl and 8 moles of 1,4: 3,6-dianhydro-D-sorbitol (isosorbide) are mixed in a reactor with 103 moles of acetic anhydride and flushed through with a gentle stream of nitrogen.
  • the mixture is heated to 140 ° C. with stirring in the course of 15 minutes and this temperature is maintained for 30 minutes.
  • the temperature is then raised to 325 ° C. in the course of 165 minutes and the melt continues at this temperature for 30 minutes touched.
  • Acetic acid begins to distill off at approx. 220 ° C.
  • the nitrogen purge is then stopped and a vacuum is slowly applied.
  • the melt is used for more
  • the polymer has a brilliant, yellow color that appears bluish green when viewed at an angle. The color already appears during the condensation in a vacuum and is retained after cooling.
  • the polymer has a brilliant, yellowish green color that appears blue when viewed obliquely. The color already appears during the condensation in a vacuum and is retained after cooling.
  • Example 1 The cholesteric liquid crystal polymer described in Example A is used
  • the cLCP granules are ground using an ultracentrifugal mill with a 0.1 mm sieve.
  • the regrind is then sifted, the sifter setting being selected so that the average grain size is between 5 and 10 ⁇ m.
  • a 35% non-aqueous dispersion in isobutanol is mixed with the viewed material.
  • the dispersion is applied to a Kapton film using a doctor blade, the gap width of which is 24 ⁇ m. After the dispersion application has dried, the powder is baked at 280 ° C. for 5 minutes. The film shows an orange color that appears green when viewed obliquely.
  • the cLCP layer is very well developed and homogeneous. The layer thickness is 8 to 11 ⁇ m.
  • the carrier film is passed over a small-diameter deflection roller, the cholesteric polymer film peeling off.
  • the polymer particles are ground in a universal mill.
  • the millbase is sieved through a sieve with a mesh size of 63 ⁇ m.
  • the effect pigment obtained is divided into a 2-
  • Component clear varnish incorporated, sprayed onto a black-primed sheet and coated with clear varnish. After baking, the varnish shows a copper color, which appears green when viewed at an angle.
  • the cLCP dispersion job is prepared as described in Example 1.
  • the polymer described in Example B is used as the cholesteric liquid crystal polymer.
  • the polymer powder is covered with a second Kapton film and rolled over at 280 ° C. using a hand roller.
  • the cover film After cooling, the cover film is removed.
  • the cLCP film shows a green color that appears blue when viewed obliquely.
  • the layer thickness is 7
  • Effect pigment is prepared as described in Example 1. After baking in the varnish on a black background, the effect pigment shows a yellowish green color, which when viewed obliquely appears greenish blue.
  • Example 3
  • the cLCP dispersion job is prepared as described in Example 1.
  • the polymer described in Example A is used as the cholesteric liquid crystal polymer.
  • the polymer powder is covered with a silicon-coated aluminum foil and rolled over at 280 ° C. using a hand roller.
  • the aluminum cover film is removed and the cLCP film is post-annealed at 280 ° C. for 20 seconds.
  • the film shows a brilliant orange color that appears green when viewed obliquely.
  • the layer thickness is 8 to 17 ⁇ m.
  • Effect pigment is prepared as described in Example 1. After baking in the paint on a black background, the effect pigment shows a copper color that appears green when viewed at an angle.
  • the cLCP granules are ground using an ultracentrifugal mill with a 0.1 mm sieve.
  • the regrind is then sifted, the sifter setting being selected so that the average grain size is between 5 and 10 ⁇ m.
  • the dispersion is applied to a doctor blade with a gap width of 24 ⁇ m
  • the cLCP layer is very well developed and homogeneous.
  • the layer thickness is 8 - 11 ⁇ m.
  • Polymer particles are ground in a universal mill.
  • the regrind becomes Narrowing the particle size distribution through a sieve with a mesh size of 63 ⁇ m.
  • the effect pigment obtained is worked into a two-component clear coat, sprayed onto a black-primed sheet and coated with clear coat. After baking, the varnish shows a copper color, which appears green when viewed at an angle.
  • the coated aluminum foil is dried over a hot metal surface and the lower liquid crystal polymer layer is produced.
  • the dwell time on the hot surface is 3 - 5 seconds at a surface temperature of 350 ° C.
  • the film shows a green color, which appears blue when viewed obliquely.
  • the cLCP layer is very well developed and homogeneous.
  • the layer thickness is 3 - 5 ⁇ m.
  • a 1% by weight dispersion of platelet-shaped graphite particles for example Graphitan 7700®, commercially available from Ciba SC
  • 2% aqueous carboxymethyl cellulose Teylose H200X®, commercially available from Clariant
  • Dispersion of the cholesteric liquid crystal polymer is applied with a 24 ⁇ m doctor blade and, after drying, again by pulling the film over a metal surface of 350 ° C. surface temperature with an average residence time of 3-5 seconds, the upper liquid crystal polymer layer is produced.
  • the middle, light-absorbing graphite layer gives a covering
  • Example 6 Polymer film that appears dark green when viewed vertically and dark blue when viewed obliquely.
  • the total layer thickness is 7 - 12 ⁇ m.
  • the effect pigment is prepared as described in Example 4. However, the aluminum foil is dissolved in semi-concentrated sodium hydroxide solution. The effect pigment shows a dark green color after baking in the varnish, which appears dark blue when viewed at an angle.
  • Example 6
  • Example A The polymer described in Example A is used as the cholesteric liquid crystal polymer.
  • the cLCP granules are ground using an ultracentrifugal mill with a 0.1 mm sieve.
  • the regrind is then sifted, the sifter setting preferably being chosen so that the average grain size is between 5 and 10 ⁇ m.
  • a 35% non-aqueous dispersion in isobutanol is mixed with the viewed material.
  • the dispersion is applied to a doctor blade with a gap width of 24 ⁇ m
  • the coated film is drawn through an alkaline solution (5% sodium hydroxide solution) and the cholesteric polymer film is separated with a brush.
  • the polymer particles are ground in a universal mill.
  • the regrind is used to narrow the particle size distribution through a 63 ⁇ m sieve

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Abstract

L'invention concerne un procédé de production de films minces de polymères à cristaux liquides cholestériques (PCLc) thermoplastiques. Dans le procédé selon l'invention, on applique un ou plusieurs PCLc thermoplastiques sous forme de dispersion non aqueuse sur un substrat planaire et on les chauffe jusqu'à atteindre ou dépasser la température de chiralisation.
PCT/EP1998/005420 1997-09-08 1998-08-26 Procede de production de films minces a partir d'une dispersion non aqueuse et pigments a effet produits a partir de ces films et dont la coloration depend de l'angle d'observation WO1999013019A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19739263.6 1997-09-08
DE1997139263 DE19739263A1 (de) 1997-09-08 1997-09-08 Verfahren zur Herstellung von dünnen Filmen aus nicht-wäßriger Dispersion und daraus hergestellte Effektpigmente mit vom Betrachtungswinkel abhängiger Farbigkeit

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DE19940682A1 (de) * 1999-08-27 2001-03-01 Basf Ag Cholesterisches Schichtmaterial mit verbessertem Farbeindruck und Verfahren zu dessen Herstellung
TWI240672B (en) * 2000-06-20 2005-10-01 Sumitomo Chemical Co Elastomer molded product
ES2615215T3 (es) * 2011-09-16 2017-06-05 Basf Se Sistema de recubrimiento
CA3039666C (fr) 2016-10-28 2022-08-23 Ppg Industries Ohio, Inc. Revetements d'augmentation des distances de detection proche infrarouge
KR20210087991A (ko) 2018-11-13 2021-07-13 피피지 인더스트리즈 오하이오 인코포레이티드 은닉 패턴을 검출하는 방법
US11561329B2 (en) 2019-01-07 2023-01-24 Ppg Industries Ohio, Inc. Near infrared control coating, articles formed therefrom, and methods of making the same

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DE19612975A1 (de) * 1996-04-01 1997-10-02 Hoechst Ag Effektbeschichtungen mit vom Betrachtungswinkel abhängigem Farbeindruck
EP0872534A1 (fr) * 1997-04-17 1998-10-21 Clariant GmbH Revêtement à effets, dont la couleur perçue dépend de l'angle d'observation
EP0872336A2 (fr) * 1997-04-17 1998-10-21 Clariant GmbH Laminé polymère ayant un pouvoir couvrant amélioré

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DE19612975A1 (de) * 1996-04-01 1997-10-02 Hoechst Ag Effektbeschichtungen mit vom Betrachtungswinkel abhängigem Farbeindruck
EP0872534A1 (fr) * 1997-04-17 1998-10-21 Clariant GmbH Revêtement à effets, dont la couleur perçue dépend de l'angle d'observation
EP0872336A2 (fr) * 1997-04-17 1998-10-21 Clariant GmbH Laminé polymère ayant un pouvoir couvrant amélioré

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103249758A (zh) * 2010-12-10 2013-08-14 沙伯基础创新塑料知识产权有限公司 包含异山梨醇的聚碳酸酯和它们的制备

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