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WO2021259825A1 - Matériau polymérisable à cristaux liquides et film polymérisé à cristaux liquides - Google Patents

Matériau polymérisable à cristaux liquides et film polymérisé à cristaux liquides Download PDF

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Publication number
WO2021259825A1
WO2021259825A1 PCT/EP2021/066752 EP2021066752W WO2021259825A1 WO 2021259825 A1 WO2021259825 A1 WO 2021259825A1 EP 2021066752 W EP2021066752 W EP 2021066752W WO 2021259825 A1 WO2021259825 A1 WO 2021259825A1
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independently
group
polymerisable
compounds
groups
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PCT/EP2021/066752
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English (en)
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Jung-Min Lee
Hoo-Yong LEE
Hyun-Jin Yoon
Heui-Seok Jin
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Merck Patent Gmbh
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Publication of WO2021259825A1 publication Critical patent/WO2021259825A1/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
    • C09K19/52—Liquid crystal materials characterised by components which are not liquid crystals, e.g. additives with special physical aspect: solvents, solid particles
    • C09K19/54—Additives having no specific mesophase characterised by their chemical composition
    • 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
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K2019/0444—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit characterized by a linking chain between rings or ring systems, a bridging chain between extensive mesogenic moieties or an end chain group
    • C09K2019/0448—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit characterized by a linking chain between rings or ring systems, a bridging chain between extensive mesogenic moieties or an end chain group the end chain group being a polymerizable end group, e.g. -Sp-P or acrylate

Definitions

  • the invention relates to a polymerisable LC material comprising one or more di- or multireactive mesogenic compounds, one or more compounds of formula UVI, 10 and one or more compounds of formula TRI, 15 20 wherein the individual radicals have one of the meaning as given in the claims.
  • the present invention relates also to a method for its 25 preparation, a polymer film with improved thermal durability and UV stability obtainable from a corresponding polymerisable LC material, to a method of preparation of such polymer film, and to the use of such polymer film and said polymerisable LC material for optical, electro-optical, decorative or security devices.
  • Polymerizable liquid crystal materials are known in prior art for the preparation of anisotropic polymer films with uniform orientation. These 35 films are usually prepared by coating a thin layer of a polymerizable liquid crystal mixture onto a substrate, aligning the mixture into uniform orientation and polymerizing the mixture. The orientation of the film can be planar, i.e.
  • liquid crystal molecules are oriented substantially parallel to the layer, homeotropic (rectangular or perpendicular to the layer) or tilted.
  • Such optical films are described, for example, in EP 0940707 B1, EP 0 888565 B1 and GB 2329393 B1.
  • Polymerisable liquid crystal (LC) materials while stable at room temperature, can degrade when subjected to increased temperatures. For example, when heated for a period of time the optical properties such as dispersion or retardance decreases and as such, the performance of the optical film degrades over time. This can be attributed, in particular, to a low degree of polymerisation and a corresponding high content of residual free radicals in the polymer, polymer shrinkage, and/or thermo-oxidative degradation.
  • Thermo-oxidative degradation is the breakdown of a polymer network catalysed by oxidation at high temperatures.
  • antioxidant additives or short antioxidants, can be used to reduce the thermo-oxidative degradation of polymers when subjected to increased temperatures. This is especially important when optical films are utilized for an in-cell application due to the high temperatures. In particular, the optical film has to endure when annealing the polyimide layer in the LC cell.
  • the documents WO 2009/86911 A1 and JP 5354238 B1 describe polymerisable liquid crystal (LC) materials comprising the commercially available antioxidant Irganox®1076.
  • such polymerisable LC material should preferably be applicable for the preparation of different, uniform aligned polymer networks, such as polymer films or polymer network LC applications, and should, in particular at the same time, - show a favourable adhesion to a substrate, - be highly transparent to VIS-light, - exhibit a reduced yellow colouration over time (yellowing) and - show a favourable high temperature stability or durability, and in addition, - show a favourable high thermal and/or UV stability or durability, and in addition, - the uniform aligned polymer films should be produced by compatible, commonly known methods for the mass production.
  • Other aims of the present invention are immediately evident to the person skilled in the art from the following detailed description.
  • the present invention relates to a polymerizable LC material comprising at least one di- or multireactive mesogenic compound, one or more compounds of formula UVI, wherein the individual radicals have the following meanings:
  • R 1 to R 5 denote each independently selected from the group consisting of H, -alkyl, —OH, -alkylaryl, -alkylheteroaryl, -cycloalkyl, cycloheteroalkyl, alkenyl, aryl and -SO 3 H
  • R 6 and R 7 denote each and independently a hydrogen atom, a hydroxy group, or a halogen atom, or R 6 and R 7 form an optionally substituted cycloalkyl or cycloheteroalkyl ring, and one
  • the invention also relates to a corresponding method of production for the polymerisable LC material.
  • the invention further relates to a polymer network or polymer film obtainable, preferably obtained, from the polymerisable LC material, as described above and below and to a method of production of a polymer film, as described above and below.
  • the invention further relates to a method of increasing the UV stability of a polymer film, obtainable, preferably obtained, from a polymerisable LC material as described above and below, by adding one or more compounds of formula UVI and one or more compounds of formula TRI to the LC material before polymerisation.
  • the invention further relates to the use of a polymer network or polymer film or polymerisable LC material, as described above and below, in optical, electrooptical, information storage, decorative and security applications, like liquid crystal displays, projection systems, polarisers, compensators, alignment layers, circular polarisers, colour filters, decorative images, liquid crystal pigments, reflective films with spatially varying reflection colours, multicolour images, non-forgeable documents like identity or credit cards or banknotes.
  • a polymer network or polymer film or polymerisable LC material as described above and below, in optical, electrooptical, information storage, decorative and security applications, like liquid crystal displays, projection systems, polarisers, compensators, alignment layers, circular polarisers, colour filters, decorative images, liquid crystal pigments, reflective films with spatially varying reflection colours, multicolour images, non-forgeable documents like identity or credit cards or banknotes.
  • the invention further relates to an optical component or device, polariser, patterned retarder, compensator, alignment layer, circular polariser, colour filter, decorative image, liquid crystal lens, liquid crystal pigment, reflective film with spatially varying reflection colours, multicolour image for decorative or information storage, comprising at least one polymer network or polymer film or polymerisable LC material, as described above and below
  • an optical component or device polariser, patterned retarder, compensator, alignment layer, circular polariser, colour filter, decorative image, liquid crystal lens, liquid crystal pigment, reflective film with spatially varying reflection colours, multicolour image for decorative or information storage, comprising at least one polymer network or polymer film or polymerisable LC material, as described above and below
  • a liquid crystal display comprising at least one polymer network or polymer film or polymerisable LC material or an optical component, as described above and below.
  • the invention further relates to authentification, verification or security marking, coloured or multicolour image for security use, non-forgeable object or document of value like an identity or credit card or a banknote, comprising a polymer network or polymer film or polymerisable LC material or an optical component as described above and below.
  • polymer will be understood to mean a molecule that encompasses a backbone of one or more distinct types of repeating units (the smallest constitutional unit of the molecule) and is inclusive of the commonly known terms “oligomer”, “copolymer”, “homopolymer” and the like.
  • polymer is inclusive of, in addition to the polymer itself, residues from initiators, catalysts, and other elements attendant to the synthesis of such a polymer, where such residues are understood as not being covalently incorporated thereto. Further, such residues and other elements, while normally removed during post polymerisation purification processes, are typically mixed or co- mingled with the polymer such that they generally remain with the polymer when it is transferred between vessels or between solvents or dispersion media.
  • (meth)acrylic polymer” as used in the present invention includes a polymer obtained from acrylic monomers, a polymer obtainable from methacrylic monomers, and a corresponding co-polymer obtainable from mixtures of such monomers.
  • polymerisation means the chemical process to form a polymer by bonding together multiple polymerisable groups or polymer precursors (polymerisable compounds) containing such polymerisable groups.
  • film and “layer” include rigid or flexible, self-supporting or freestanding films with mechanical stability, as well as coatings or layers on a supporting substrate or between two substrates.
  • liquid crystal or “LC” relates to materials having liquid- crystalline mesophases in some temperature ranges (thermotropic LCs) or in some concentration ranges in solutions (lyotropic LCs). They obligatorily contain mesogenic compounds.
  • mesogenic compound and “liquid crystal compound” mean a compound comprising one or more calamitic (rod- or board/lath-shaped) or discotic (disk-shaped) mesogenic groups.
  • mesogenic group means a group with the ability to induce liquid-crystalline phase (or mesophase) behaviour.
  • the compounds comprising mesogenic groups do not necessarily have to exhibit a liquid-crystalline mesophase themselves. It is also possible that they show liquid-crystalline mesophases only in mixtures with other compounds, or when the mesogenic compounds or materials, or the mixtures thereof, are polymerised. This includes low- molecular-weight non-reactive liquid-crystalline compounds, reactive or polymerisable liquid-crystalline compounds, and liquid-crystalline polymers.
  • a calamitic mesogenic group is usually comprising a mesogenic core consisting of one or more aromatic or non-aromatic cyclic groups connected to each other directly or via linkage groups, optionally comprising terminal groups attached to the ends of the mesogenic core, and optionally comprising one or more lateral groups attached to the long side of the mesogenic core, wherein these terminal and lateral groups are usually selected e.g. from carbyl or hydrocarbyl groups, polar groups like halogen, nitro, hydroxy, etc., or polymerisable groups.
  • reactive mesogen means a polymerisable mesogenic or liquid crystal compound, preferably a monomeric compound.
  • Non-mesogenic compound or material means a compound or material that does not contain a mesogenic group as defined above.
  • Visible light is electromagnetic radiation that has wavelength in a range from about 400 nm to about 740 nm.
  • Ultraviolet (UV) light is electromagnetic radiation with a wavelength in a range from about 200 nm to about 450 nm.
  • the director In case of uniaxial ordering of such anisotropic molecules, the director is the axis of anisotropy.
  • the term “alignment” or “orientation” relates to alignment (orientational ordering) of anisotropic units of material such as small molecules or fragments of big molecules in a common direction named “alignment direction”.
  • alignment direction In an aligned layer of liquid-crystalline or RM material the liquid- crystalline director coincides with the alignment direction so that the alignment direction corresponds to the direction of the anisotropy axis of the material.
  • uniform orientation or “uniform alignment” of a liquid- crystalline or RM material, for example in a layer of the material, mean that the long molecular axes (in case of calamitic compounds) or the short molecular axes (in case of discotic compounds) of the liquid-crystalline or RM molecules are oriented substantially in the same direction. In other words, the lines of liquid-crystalline director are parallel.
  • homeotropic structure or “homeotropic orientation” refers to a film wherein the optical axis is substantially perpendicular to the film plane.
  • planar structure or “planar orientation” refers to a film wherein the optical axis is substantially parallel to the film plane.
  • negative (optical) dispersion refers to a birefringent or liquid crystalline material or layer that displays reverse birefringence dispersion where the magnitude of the birefringence ( ⁇ n) increases with increasing wavelength ( ⁇ ). I.e. ⁇ ⁇ n (450) ⁇ ⁇ ⁇ n (550) ⁇ , or ⁇ n (450)/ ⁇ n (550) ⁇ 1, where ⁇ n (450) and ⁇ n (550) are the birefringence of the material measured at wavelengths of 450nm and 550nm respectively.
  • positive (optical) dispersion means a material or layer having I ⁇ n (450) I> I ⁇ n (550) I or ⁇ n (450)/ ⁇ n (550) > 1.
  • the optical dispersion can be expressed either as the "birefringence dispersion" by the ratio ⁇ n(450)/ ⁇ n(550), or as “retardation dispersion” by the ratio R(450)/R(550), wherein R(450) and R(550) are the retardation of the material measured at wavelengths of 450nm and 550nm respectively. Since the layer thickness d does not change with the wavelength, R (450)/R (550) is equal to ⁇ n (450)/ ⁇ n (550).
  • a material or layer with negative or reverse dispersion has R (450)/R (550) ⁇ 1 or IR (450) I ⁇ IR (550) I
  • a material or layer with positive or normal dispersion has R (450)/R (550) > 1 or IR (450) I > ⁇ R (550) ⁇ .
  • optical dispersion means the retardation dispersion i.e. the ratio R (450)/R (550).
  • high dispersion means that the absolute value of the dispersion shows a large deviation from 1
  • the term “low dispersion” means that the absolute value of the dispersion shows a small deviation from 1.
  • high negative dispersion means that the dispersion value is significantly smaller than 1
  • low negative dispersion means that the dispersion value is only slightly smaller than 1.
  • the retardation (R( ⁇ )) of a material can be measured using a spectroscopic ellipsometer, for example the M2000 spectroscopic ellipsometer manufactured by J. A. Woollam Co., This instrument is capable of measuring the optical retardance in nanometres of a birefringent sample e.g. Quartz over a range of wavelengths typically, 370nm to 2000nm. From this data, it is possible to calculate the dispersion (R(450)/R(550) or ⁇ n(450)/ ⁇ n(550)) of a material.
  • a plate refers to an optical retarder utilizing a layer of uniaxially birefringent material with its extraordinary axis oriented parallel to the plane of the layer.
  • C plate refers to an optical retarder utilizing a layer of uniaxially birefringent material with its extraordinary axis oriented perpendicular to the plane of the layer.
  • A/C-plates comprising optically uniaxial birefringent liquid crystal material with uniform orientation, the optical axis of the film is given by the direction of the extraordinary axis.
  • An A (or C) plate comprising optically uniaxial birefringent material with positive birefringence is also referred to as "positive A (or C) plate” or "+ A (or +C) plate”.
  • An A (or C) plate comprising a film of optically uniaxial birefringent material with negative birefringence, such as discotic anisotropic materials is also referred to as "negative A (or C) plate” or “- A (or C) plate” depending on the orientation of the discotic materials.
  • a film made from a cholesteric calamitic material with a reflection band in the UV part of the spectrum also has the optics of a negative C plate.
  • n av. ((2n o 2 + n e 2 )/3) 1 ⁇ 2
  • n av. and n e 2 can be measured using an Abbe refractometer.
  • ⁇ n can then be calculated from the above equations.
  • All physical properties have been and are determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status Nov.1997, Merck KGaA, Germany and are given for a temperature of 20 °C, unless explicitly stated otherwise.
  • Carbyl group denotes a mono- or polyvalent organic group containing at least one carbon atom which either contains no further atoms (such as, for example, -C ⁇ C-) or optionally contains one or more further atoms, such as, for example, N, O, S, P, Si, Se, As, Te or Ge (for example carbonyl, etc.).
  • Hydrocarbyl group denotes a carbyl group, which additionally contains one or more H atoms and optionally one or more heteroatoms, such as, for example, N, O, S, P, Si, Se, As, Te or Ge.
  • a carbyl or hydrocarbyl group can be a saturated or unsaturated group. Unsaturated groups are, for example, aryl, alkenyl, or alkinyl groups.
  • a carbyl or hydrocarbyl group having more than 3 C atoms can be straight chain, branched and/or cyclic and may contain spiro links or condensed rings.
  • Preferred carbyl and hydrocarbyl groups are optionally substituted alkyl, alkenyl, alkinyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy having 1 to 40, preferably 1 to 25, particularly pref- erably 1 to 18 C atoms, optionally substituted aryl or aryloxy having 6 to 40, preferably 6 to 25 C atoms, or optionally substituted alkylaryl, arylalkyl, alkylaryloxy, arylalkyloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy having 6 to 40, preferably 6 to 25 C atoms.
  • carbyl and hydrocarbyl groups are C 1 -C 40 alkyl, C 2 -C 40 alkenyl, C 2 -C 40 alkinyl, C 3 -C 40 allyl, C 4 -C 40 alkyldienyl, C 4 -C 40 polyenyl, C 6 - C 40 aryl, C 6 -C 40 alkylaryl, C 6 -C 40 arylalkyl, C 6 -C 40 alkylaryloxy, C 6 -C 40 aryl- alkyloxy, C 2 -C 40 heteroaryl, C 4 -C 40 cycloalkyl, C 4 -C 40 cycloalkenyl, etc.
  • C 1 -C 22 alkyl Particular preference is given to C 1 -C 22 alkyl, C 2 -C 22 alkenyl, C 2 -C 22 alkinyl, C 3 -C 22 allyl, C 4 -C 22 alkyldienyl, C 6 -C 12 aryl, C 6 -C 20 arylalkyl, and C 2 -C 20 heteroaryl.
  • R x preferably denotes H, halogen, a straight-chain, branched or cyclic alkyl chain having 1 to 25 C atoms, in which, in addition, one or more non-adjacent C atoms may be replaced by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, and in which one or more H atoms may be replaced by fluorine, an optionally substituted aryl or aryloxy group having 6 to 40 C atoms or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 40 C atoms.
  • Preferred alkyl groups are, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, s-butyl, t-butyl, 2-methylbutyl, n-pentyl, s-pentyl, n-hexyl, 2-ethylhexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, dodecanyl, trifluoromethyl, perfluoro-n-butyl, 2,2,2-trifluoroethyl, perfluorooctyl, perfluorohexyl, etc.
  • Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl, etc.
  • Preferred alkinyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl, etc.
  • Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxy- ethoxy, n-propoxy, i-propoxy, n-butoxy, i-butoxy, s-butoxy, t-butoxy, 2- methylbutoxy, n-pentoxy, n-hexoxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy, n-dodecyloxy, etc.
  • Preferred amino groups are, for example, dimethylamino, methylamino, methylphenylamino, phenylamino, etc.
  • Aryl and heteroaryl groups can be monocyclic or polycyclic, i.e. they can have one ring (such as, for example, phenyl) or two or more rings, which may also be fused (such as, for example, naphthyl) or covalently linked (such as, for example, biphenyl), or contain a combination of fused and linked rings.
  • Heteroaryl groups contain one or more heteroatoms, prefera- bly selected from O, N, S, and Se. Particular preference is given to mono-, bi-, or tricyclic aryl groups having 6 to 25 C atoms and mono-, bi- or tricyclic heteroaryl groups having 2 to 25 C atoms, which optionally contain fused rings, and which are optionally substituted.
  • Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl, [1,1':3',1'']terphenyl-2'-yl, naphthyl, anthracene, binaphthyl, phenanthrene, pyrene, dihydropyrene, chrysene, perylene, tetracene, pentacene, benzo- pyrene, fluorene, indene, indenofluorene, spirobifluorene, etc.
  • Preferred heteroaryl groups are, for example, 5-membered rings, such as pyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, furan, thiophene, selenophene, oxazole, isoxazole, 1,2-thiazole, 1,3-thiazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, 1,2,5-thiadiazole, 1,3,4-thiadiazole, 6-membered rings, such as pyridine, pyridazine, pyrimidine, pyrazine, 1,3,5-triazine, 1,2,4-triazine, 1,2,3-triazine, 1,2,4,5-tetrazine, 1,2,3,4- tetrazine,
  • the heteroaryl groups may also be substituted by alkyl, alkoxy, thioalkyl, fluorine, fluoroalkyl or further aryl or heteroaryl groups.
  • the (non-aromatic) alicyclic and heterocyclic groups encompass both saturated rings, i.e. those that contain exclusively single bonds, and partially unsaturated rings, i.e. those that may also contain multiple bonds.
  • Heterocyclic rings contain one or more heteroatoms, preferably selected from Si, O, N, S, and Se.
  • the (non-aromatic) alicyclic and heterocyclic groups can be monocyclic, i.e. contain only one ring (such as, for example, cyclohexane), or poly- cyclic, i.e.
  • a plurality of rings such as, for example, decahydro- naphthalene or bicyclooctane. Particular preference is given to saturated groups.
  • Preferred alicyclic and heterocyclic groups are, for example, 5-membered groups, such as cyclopentane, tetrahydrofuran, tetrahydrothiofuran, pyr- rolidine, 6-membered groups, such as cyclohexane, silinane, cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1,3-dioxane, 1,3-dithiane, piperidine, 7-membered groups, such as cycloheptane, and fused groups, such as tetrahydronaphthalene, decahydronaphthalene, indane, bicyclo[1.1.1]- pentane-1,3-diyl, bicyclo[2.2.2]octane-1,4-diyl, spiro[3.3]heptane-2,6-diyl, octahydro-4,7-methanoin
  • the aryl, heteroaryl, (non-aromatic) alicyclic and heterocyclic groups optionally have one or more substituents, which are preferably selected from the group comprising silyl, sulfo, sulfonyl, formyl, amine, imine, nitrile, mercapto, nitro, halogen, C 1-12 alkyl, C 6-12 aryl, C 1-12 alkoxy, hydroxyl, or combinations of these groups.
  • Preferred substituents are, for example, solubility-promoting groups, such as alkyl or alkoxy, electron-withdrawing groups, such as fluorine, nitro or nitrile, or substituents for increasing the glass transition temperature (Tg) in the polymer, in particular bulky groups, such as, for example, t-butyl or optionally substituted aryl groups.
  • Substituted silyl or aryl preferably means substituted by halogen, -CN, R y , -OR y , -CO-R y , -CO-O-R y , -O-CO-R y or -O-CO-O-R y , in which R y denotes H, a straight-chain, branched or cyclic alkyl chain having 1 to 12 C atoms.
  • Halogen denotes F, Cl, Br or I, preferably F or Cl, more preferably F.
  • cycloheteroalkyl ring or ““cycloheteroalkyl” within the meaning of the present invention is denoted to mean a non-aromatic monocyclic or polycyclic alkyl ring comprising at least one heteroatom and may, also be referred to as heterocycloalkyl ring.
  • alkylaryl as used in the context of the present invention relates to radicals with the -alkyl-aryl structure which are attached via the alkyl group. Both the alkyl group and the aryl group include substituted radicals in this context.
  • alkylheteroaryl as used in the context of the present invention relates to radicals with the -alkyl-heteroaryl structure which are attached via the alkyl group. Both the alkyl group and the heteroaryl group include substituted radicals in this context.
  • substituted reference is made to the above remarks.
  • all multireactive polymerisable compounds and sub-formulae thereof contain instead of one or more radicals P-Sp-, one or more branched radicals containing two or more polymerisable groups P (multireactive polymerisable radicals).
  • Suitable radicals of this type, and polymerisable compounds containing them, are described, for example, in US 7,060,200 B1 or US 2006/0172090 A1.
  • multireactive polymerisable radicals selected from the following formulae: -X-alkyl-CHP x -CH 2 -CH 2 P y I*a -X-alkyl-C(CH 2 P x )(CH 2 P y )-CH 2 P z I*b -X-alkyl-CHP x CHP y -CH 2 P z I*c -X-alkyl-C(CH 2 P x )(CH 2 P y )-C aa H 2aa+1 I*d -X-alkyl-CHP x -CH 2 P y I*e -X-alkyl-CHP x P y I*f -X-alkyl-CP x P y -C aa H 2aa+1 I*g -X-alkyl-C(CH 2 P v )(CH 2 P w )-CH 2 OCH 2 -C(CH 2 P x )
  • X' is preferably -O-, -S- -CO-, -COO-, -OCO-, -O-COO-, -CO-NR xx -, -NR xx -CO-, -NR xx -CO-NR yy - or a single bond.
  • Typical spacer groups Sp' are, for example, -(CH 2 ) p1 -, -(CH 2 CH 2 O) q1 - CH 2 CH 2 -, -CH 2 CH 2 -S-CH 2 CH 2 -, -CH 2 CH 2 -NH-CH 2 CH 2 - or -(SiR xx R yy -O) p1 -, in which p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R xx and R yy have the above-mentioned meanings.
  • Particularly preferred groups -X'-Sp'- are -(CH 2 ) p1 -, -O-(CH 2 ) p1 -, -OCO- (CH 2 ) p1 -, -OCOO-(CH 2 ) p1 -, in which p1 is an integer from 1 to 12.
  • Particularly preferred groups Sp' are, for example, in each case straight- chain, methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxyethylene, methyleneoxybutylene, ethylenethioethylene, ethylene-N-methyliminoethylene, 1-methylalkylene, ethenylene, propenylene and butenylene.
  • trans-1,4-cyclohexylene and denote 1,4-phenylene.
  • a “polymer network” is a network in which all polymer chains are interconnected to form a single macroscopic entity by many crosslinks.
  • the polymer network can occur in the following types: -
  • a graft polymer molecule is a branched polymer molecule in which one or more the side chains are different, structurally or configurationally, from the main chain.
  • - A star polymer molecule is a branched polymer molecule in which a single branch point gives rise to multiple linear chains or arms.
  • the star polymer molecule is said to be regular. If adjacent arms are composed of different repeating subunits, the star polymer molecule is said to be variegated.
  • a comb polymer molecule consists of a main chain with two or more three-way branch points and linear side chains. If the arms are identical the comb polymer molecule is said to be regular.
  • a brush polymer molecule consists of a main chain with linear, unbranched side chains and where one or more of the branch points has four-way functionality or larger.
  • R 1 to R 5 denote each independently selected from the group consisting of H, -alkyl, -OH, -alkylaryl, -alkylheteroaryl, -cycloalkyl, cycloheteroalkyl, alkenyl, aryl and -SO 3 H
  • R 6 and R 7 denote each and independently a hydrogen atom, a hydroxy group, or a halogen atom
  • R 8 to R 13 are each independently radicals selected from the group consisting of H, alkyl, aryl, heteroaryl, alkylaryl, alkylheteroaryl, alkenyl and alkynyl
  • X 1 denotes O or S
  • R 14 and R 15 is selected from the group consisting of H, -C( ⁇ O)R 8 , alkyl, alkenyl, alkynyl, aryl, cycloalkyl, heteroaryl and cycloheteroalkyl.
  • the compounds of formula UVI are selected from the group of compounds wherein at least one of R 1 to R 5 denotes - OH; preferably at least R 1 denotes -OH. Accordingly, the compounds of formula UVI are selected from the group of compounds of the following subformulae :
  • R 2 to R 5 denote each independently selected from the group consisting of H, -alkyl, -OH, -alkylaryl, -alkylheteroaryl, -cycloalkyl, cycloheteroalkyl, alkenyl, aryl and -SO3H
  • R 6 and R 7 denote each and independently a hydrogen atom, a hydroxy group, or a halogen atom
  • R 8 to R 13 are each independently radicals selected from the group consisting of H, alkyl, aryl, heteroaryl, alkylaryl, alkylheteroaryl, alkenyl and alkynyl
  • X 1 denotes O or S
  • R 14 and R 15 is selected from the group consisting of H, -C( ⁇ O)R 8 , alkyl, alkenyl, alkynyl, aryl, cycloalkyl, heteroaryl and cycloheteroalkyl.
  • the compounds of formula UVI are selected from the group of compounds wherein at least one of R 3 or R 5 denotes -H; preferably both R 3 and R 5 denotes -H. Accordingly, the compounds of formula UVI are selected from the group of compounds of the following subformulae :
  • R 2 and R 4 denote each independently selected from the group consisting of H, -alkyl, -OH, -alkylaryl, -alkylheteroaryl, -cycloalkyl, cycloheteroalkyl, alkenyl, aryl and -SO3H
  • R 6 and R 7 denote each and independently a hydrogen atom, a hydroxy group, or a halogen atom
  • R 8 to R 13 are each independently radicals selected from the group consisting of H, alkyl, aryl, heteroaryl, alkylaryl, alkylheteroaryl, alkenyl and alkynyl
  • X 1 denotes O or S
  • R 14 and R 15 is selected from the group consisting of H, -C( ⁇ O)R 8 , alkyl, alkenyl, alkynyl, aryl, cycloalkyl, heteroaryl and cycloheteroalkyl.
  • R 2 and R 4 denote each independently selected from the group consisting of H, -alkyl, -OH, -alkylaryl, -alkylheteroaryl, -cycloalkyl, cycloheteroalkyl, alkenyl, aryl and -SO 3 H
  • R 6 and R 7 denote each and independently a hydrogen or halogen, preferably hydrogen I, k, m, n, o, and p are each independently an integer from 2 to 20, preferably 2 to 10, more preferably 2 to 5
  • X 1 denotes O or S
  • R 14 and R 15 is selected from the group consisting of H, -C( ⁇ O)alkyl, alkyl, alkenyl, alkynyl, aryl, cycloalkyl, heteroaryl and cycloheteroalkyl.
  • the compounds of formula UVI are selected from the group of compounds wherein R 2 and R 4 denotes preferably each independently alkylaryl groups, especially alkylphenyl groups, or alkyl groups, especially straight chain or branched alkyl groups having 5 to 15 carbon atoms, wherein one or more -(CH 2 )- groups might be substituted by -COO-, -OCO- in that way that no two oxygen atoms are linked together.
  • the compounds of formula UVI are selected from the group of compounds of the following subformulae:
  • the proportion of compounds of formula UVI in the LC medium is from 0.01 to 5%, very preferably from 0.05 to 3 %, in particular 0.1 to 2% by weight of the total medium.
  • the compounds of the formula UVI and sub-formulae thereof can be pre- pared analogously to processes known to the person skilled in the art and described in standard works of organic chemistry, such as, for example, in Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Thieme-Verlag, Stuttgart.
  • Tinuvin® (BASF, Germany), such as, Tinuvin®328, Tinuvin® 384, Tinuvin®900, Tinuvin®928, Tinuvin®970 and Tinuvin®1130.
  • Preferred compounds of formula TRI are selected from the following subformulae TRI-1: wherein R 2 to R 9 and R a have one of the meanings as given under formula TRI.
  • R 2 to R 9 and R a have one of the meanings as given under formula TRI or TRI-1.
  • Further preferred compounds of formula TRI are selected from the following subformula TRI-3: wherein R 2 to R 9 and R a have one of the meanings as given under formula TRI or TRI-1.
  • Further preferred compounds of formula TRI are selected from the following subformula TRI-4: wherein R 2 , R 5 , R 6 , R 8 and R 9 and R a have one of the meanings as given under formula TRI or TRI-1.
  • R 2 , R 6 , and R 9 denote each methyl, ethyl, propyl, preferably each methyl.
  • Y 1 , Y 2 and Y 3 are identical and denote -COO-, or -OCO-.
  • m, n and o are identical and denote an integer between 1 to 4, preferably 2.
  • X 1 , X 2 and X 3 are identical and each denote a straight chain or branched alkyl having 1 to 12, preferably 1 to 8 C atoms. Example for especially preferred compounds of formula TRI are given in the following list,
  • the proportion of compounds of formula TRI in the LC medium is from 0.01 to 5%, very preferably from 0.1 to 3 %, in particular 0.5 to 2%.
  • the proportion of compounds of formula TRI in the LC medium is from 10 to 5000 ppm, very preferably from 100 to 3000 ppm, in particular 500 to 2000 ppm.
  • the combination of compounds of formula TRI and UVI leads to polymerizable LC media having a further reliability in terms of UV light stress.
  • Preferred groups A 1 and A 2 include, without limitation, furan, pyrrol, thiophene, oxazole, thiazole, thiadiazole, imidazole, phenylene, cyclohexylene, bicyclooctylene, cyclohexenylene, pyridine, pyrimidine, pyrazine, azulene, indane, fluorene, naphthalene, tetrahydronaphthalene, anthracene, phenanthrene and dithienothiophene, all of which are unsubstituted or substituted by 1, 2, 3 or 4 groups L as defined above.
  • Particular preferred groups A 1 and A 2 are selected from 1,4-phenylene, pyridine-2,5-diyl, pyrimidine-2,5-diyl, thiophene-2,5-diyl, naphthalene-2,6- diyl, 1,2,3,4-tetrahydro-naphthalene-2,6-diyl, indane-2,5-diyl, bicyclooctylene or 1,4-cyclohexylene wherein one or two non-adjacent CH 2 groups are optionally replaced by O and/or S, wherein these groups are unsubstituted or substituted by 1, 2, 3 or 4 groups L as defined above.
  • Very preferred direactive mesogenic compounds of formula DRM are selected from the following formulae:
  • P 0 is, in case of multiple occurrence independently of one another, a polymerisable group, preferably an acryl, methacryl, oxetane, epoxy, vinyl, heptadiene, vinyloxy, propenyl ether or styrene group
  • L has on each occurrence identically or differently one of the meanings given for L 1 in formula DRM, and is preferably, in case of multiple occurrence independently of one another, selected from F, Cl, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 5 C atoms, r is 0, 1, 2, 3 or 4, x and y are independently of each other 0 or identical or different integers from 1 to 12, z is each and independently, 0 or 1, with z being 0 if the adjacent x or y is 0.
  • compounds of formula MRM1, MRM2, MRM3, MRM4, MRM5, MRM6, MRM7, MRM9 and MRM10 especially those of formula MRM1, MRM4, MRM6, and MRM7, and in particular those of formulae MRM1and MRM7.
  • the compounds of the formulae DRM, MRM, and sub-formulae thereof can be pre-pared analogously to processes known to the person skilled in the art and described in standard works of organic chemistry, such as, for example, in Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Thieme-Verlag, Stuttgart.
  • the proportion of said mono-, di- or multireactive liquid-crystalline compounds in a polymerisable liquid-crystalline material according to the present invention as a whole is preferably in the range from 30 to 99.9 % by weight, more preferably in the range from 40 to 99.9 % by weight and even more preferably in the range from 50 to 99.9% by weight.
  • the proportion of the di- or multireactive polymerisable mesogenic compounds in a polymerisable liquid-crystalline material according to the present invention as a whole is preferably in the range from 5 to 99 % by weight, more preferably in the range from 10 to 97 % by weight and even more preferably in the range from 15 to 95% by weight.
  • the proportion of the monoreactive polymerisable mesogenic compounds in a polymerisable liquid-crystalline material according to the present invention as a whole is, if present, preferably in the range from 5 to 80% by weight, more preferably in the range from 10 to 75 % by weight and even more preferably in the range from 15 to 70 % by weight.
  • the proportion of the multireactive polymerizable mesogenic compounds in a polymerisable liquid-crystalline material according to the present invention as a whole is, if present, preferably in the range from 1 to 30 % by weight, more preferably in the range from 2 to 20 % by weight and even more preferably in the range from 3 to 10% by weight.
  • the polymerisable LC material does not contain polymerizable mesogenic compounds having more than two polymerisable groups. In another preferred embodiment the polymerisable LC material does not contain polymerizable mesogenic compounds having less than two polymerisable groups. In another preferred embodiment the polymerisable LC material is an achiral material, i.e. it does not contain any chiral polymerizable mesogenic compounds or other chiral compounds. In a further preferred embodiment, the polymerisable LC material comprises at least one monoreactive mesogenic compound, preferably selected from formulae MRM-1, at least one direactive mesogenic compound, preferably selected from formula DRMa-1, one or more compounds of formula UVI, and one or more compound of formula TRI.
  • the polymerisable LC material comprises at least one monoreactive mesogenic compound, preferably selected from formula MRM-7, at least one direactive mesogenic compound, preferably selected from formula DRMa-1, one or more compounds of formula UVI, and one or more compound of formula TRI.
  • the polymerisable LC material comprises at least two monoreactive mesogenic compound, preferably selected from compounds of formulae MRM-1 and/or MRM-7, at least one direactive mesogenic compound, preferably selected from formula DRMa-1, one or more compounds of formula UVI, and one or more compound of formula TRI.
  • the polymerisable LC material comprises at least two monoreactive mesogenic compounds, preferably selected from compounds of formulae MRM-1 and/or MRM-7, at least two direactive mesogenic compounds, preferably selected from compounds of formula DRMa-1, one or more compounds of formula UVI, and one or more compound of formula TRI.
  • the polymerisable LC material comprises at least two direactive mesogenic compounds, preferably selected from compounds of formula DRMa-1, one or more compounds of formula UVI, and one or more compound of formula TRI.
  • the polymerisable LC material as described above comprises additionally one or more compounds of formula ND, wherein U 1,2 are independently of each other selected from including their mirror images, wherein the rings U 1 and U 2 are each bonded to the group -(B)q- via the axial bond, and one or two non-adjacent CH2 groups in these rings are optionally replaced by O and/or S, and the rings U 1 and U 2 are optionally substituted by one or more groups L, L has on each occurrence identically or differently one of the meanings given for L 1 in formula DRM, and is preferably, in case of multiple occurrence independently of one another, selected from F, Cl, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 5 C atoms, Q 1,2 are independently of each other CH or SiH, Q 3 is C or Si, B is in
  • the subgroups forming the bridging group B in formula ND are preferably selected from groups having a bonding angle of 120° or more, preferably in the range of 180°.
  • Very preferred are -C ⁇ C- groups or divalent aromatic groups connected to their adjacent groups in para- position, like e.g.1,4-phenylene, naphthalene-2,6-diyl, indane-2,6-diyl or thieno[3,2-b]thiophene-2,5-diyl.
  • bridging group, or -(B) q - in formula ND comprises one or more groups selected from the group consisting of -C ⁇ C-, optionally substituted 1,4-phenylene and optionally substituted 9H-fluorene-2,7-diyl.
  • the subgroups, or B in formula ND are preferably selected from the group consisting of -C ⁇ C-, optionally substituted 1,4-phenylene and optionally substituted 9H-fluorene-2,7-diyl, wherein in the fluorene group the H-atom in 9-position is optionally replaced by a carbyl or hydrocarbyl group.
  • the bridging group, or -(B) q - in formula ND are selected from -C ⁇ C-, -C ⁇ C-C ⁇ C-, -C ⁇ C-C ⁇ C-C ⁇ C-, -C ⁇ C-C ⁇ C-C ⁇ C-C ⁇ C-, (L) (L) (L) wherein r is 0, 1, 2, 3 or 4 and L has the meaning as described below.
  • the non-aromatic rings of the mesogenic groups where the bridging group is attached are preferably selected from 5 , wherein R 5 is as defined in formula ND.
  • the aromatic groups A 1-4 in formula ND may be mononuclear, i.e. having only one aromatic ring (like for example phenyl or phenylene), or polynuclear, i.e. having two or more fused rings (like for example napthyl or naphthylene).
  • mono-, bi- or tricyclic aromatic or heteroaromatic groups with up to 25 C atoms that may also comprise fused rings and that are optionally substituted.
  • the non-aromatic carbocyclic and heterocyclic rings A 1-4 in the compounds of formula ND include those which are saturated (also referred to as "fully saturated"), i.e.
  • non-aromatic rings may also comprise one or more hetero atoms, preferably selected from Si, O, N and S.
  • the non-aromatic and aromatic rings, or A 1-4 in formula ND are selected from trans-1,4-cyclohexylene and 1,4-phenylene that is optionally substituted with one or more groups L.
  • Very preferred are compounds of formula ND, wherein m and p are 1 and n and o are 1 or 2.
  • the linkage groups connecting the aromatic and non-aromatic cyclic groups in the mesogenic groups, or Z 1-4 are preferably selected from -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, - CO-NR 0 -, -NR 0 -CO-, -NR 0 -CO-NR 0 -, -OCH 2 -, -CH 2 O-, -SCH 2 -, -CH 2 S-, - CF 2 O-, -OCF 2 -, -CF 2 S-, -SCF 2 - , -CH 2 CH 2 -, -(CH 2 ) 3 -, -(CH 2 ) 4 -, -CF
  • the compounds of formula ND comprise one or more terminal groups, like R 1-4 , or substituents, like R 5 , that are substituted by two or more polymerisable groups P or P-Sp- (multifunctional polymerisable groups).
  • Suitable multifunctional polymerisable groups of this type are disclosed for example in US 7,060,200 B1 or US 2006/0172090 A1.
  • Very preferred compounds of formula ND are those of the following sub formulae:
  • R 1-5 , A 1-4 , Z 1-4 , B, m, n, o, p and q have one the meanings given above.
  • Z has one of the meanings of Z 1 given above
  • R has one of the meanings of R 1 as given above that is different from P-Sp-
  • P, Sp, L and r are as defined above
  • the benzene rings in the mesogenic groups are optionally substituted by one or more groups L as defined above.
  • Preference is furthermore given to a polymerisable liquid crystalline medium wherein the compounds of formula ND are selected from the group of compounds of formula ND 25 or ND 26, in particular wherein Z denotes – COO-, r is in each occurrence 0, and P, Sp are as defined above.
  • P-Sp- in these preferred compounds is preferably P-Sp'-X', with X' preferably being -O-, -COO- or -OCOO-.
  • the compounds of formula ND, its subformulae and suitable methods for their synthesis are disclosed in WO 2008/119427 A1.
  • the amount of compounds of formula ND in the polymerisable LC material is preferably from 1 to 50 %, very preferably from 1 to 40 %.
  • Especially the combination of compound or formula UVI with compounds of formula ND leads to a beneficial decrease of the optical dispersion in comparison to polymerisable LC materials utilizing not that specific combination and leads to a beneficial thermal durability of the optical dispersion and/or retardation..
  • the polymerisable LC material optionally comprises one or more additives selected from the group consisting of further polymerisation initiators, antioxidants, surfactants, stabilisers, catalysts, sensitizers, inhibitors, chain-transfer agents, co-reacting monomers, reactive thinners, surface-active compounds, lubricating agents, wetting agents, dispersing agents, hydrophobing agents, adhesive agents, flow improvers, degassing or defoaming agents, deaerators, diluents, reactive diluents, auxiliaries, colourants, dyes, pigments and nanoparticles.
  • additives selected from the group consisting of further polymerisation initiators, antioxidants, surfactants, stabilisers, catalysts, sensitizers, inhibitors, chain-transfer agents, co-reacting monomers, reactive thinners, surface-active compounds, lubricating agents, wetting agents, dispersing agents, hydrophobing agents, adhesive agents, flow improvers, degassing or defo
  • the polymerisable LC material optionally comprises one or more additives selected from polymerisable non- mesogenic compounds (reactive thinners).
  • the amount of these additives in the polymerisable LC material is preferably from 0 to 30 %, very preferably from 0 to 25 %.
  • the reactive thinners used are not only substances which are referred to in the actual sense as reactive thinners, but also auxiliary compounds already mentioned above which contain one or more complementary reactive units or polymerizable groups P, for example hydroxyl, thiol-, or amino groups, via which a reaction with the polymerisable units of the liquid-crystalline compounds can take place.
  • the substances which are usually capable of photopolymerisation, include, for example, mono-, bi- and polyfunctional compounds containing at least one olefinic double bond.
  • examples thereof are vinyl esters of carboxylic acids, for example of lauric, myristic, palmitic and stearic acid, and of dicarboxylic acids, for example of succinic acid, adipic acid, allyl and vinyl ethers and methacrylic and acrylic esters of monofunctional alcohols, for example of lauryl, myristyl, palmityl and stearyl alcohol, and diallyl and divinyl ethers of bifunctional alcohols, for example ethylene glycol and 1,4-butanediol.
  • methacrylic and acrylic esters of polyfunctional alcohols are also suitable, for example, methacrylic and acrylic esters of polyfunctional alcohols, in particular those which contain no further functional groups, or at most ether groups, besides the hydroxyl groups.
  • examples of such alcohols are bifunctional alcohols, such as ethylene glycol, propylene glycol and their more highly condensed representatives, for example diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol etc., butanediol, pentanediol, hexanediol, neopentyl glycol, alkoxylated phenolic compounds, such as ethoxylated and propoxylated bisphenols, cyclohexanedimethanol, trifunctional and polyfunctional alcohols, such as glycerol, trimethylolpropane, butanetriol, trimethylolethane, pentaerythritol, ditrimethylolpropane, dipenta
  • polyester (meth)acrylates which are the (meth)acrylic ester of polyesterols.
  • suitable polyesterols are those which can be prepared by esterification of polycarboxylic acids, preferably dicarboxylic acids, using polyols, preferably diols.
  • the starting materials for such hydroxyl- containing polyesters are known to the person skilled in the art.
  • Dicarboxylic acids which can be employed are succinic, glutaric acid, adipic acid, sebacic acid, o-phthalic acid and isomers and hydrogenation products thereof, and esterifiable and transesterifiable derivatives of said acids, for example anhydrides and dialkyl esters.
  • Suitable polyols are the abovementioned alcohols, preferably ethyleneglycol, 1,2- and 1,3- propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexanedimethanol and polyglycols of the ethylene glycol and propylene glycol type.
  • Suitable reactive thinners are furthermore 1,4-divinylbenzene, triallyl cyanurate, acrylic esters of tricyclodecenyl alcohol of the following formula also known under the name dihydrodicyclopentadienyl acrylate, and the allyl esters of acrylic acid, methacrylic acid and cyanoacrylic acid.
  • This group includes, for example, dihydric and polyhydric alcohols, for example ethylene glycol, propylene glycol and more highly condensed representatives thereof, for example diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol etc., butanediol, pentanediol, hexanediol, neopentyl glycol, cyclohexanedimethanol, glycerol, trimethylolpropane, butanetriol, trimethylolethane, pentaerythritol, ditrimethylolpropane, dipentaerythritol, sorbitol, mannitol and the corresponding alkoxylated, in particular ethoxylated and propoxylated alcohols.
  • dihydric and polyhydric alcohols for example ethylene glycol, propylene glycol and more highly condensed representatives thereof, for example diethylene glycol, triethylene glycol, dipropylene
  • the group furthermore also includes, for example, alkoxylated phenolic compounds, for example ethoxylated and propoxylated bisphenols.
  • These reactive thinners may furthermore be, for example, epoxide or urethane (meth)acrylates.
  • Epoxide (meth)acrylates are, for example, those as obtainable by the reaction, known to the person skilled in the art, of epoxidized olefins or poly- or diglycidyl ether, such as bisphenol A diglycidyl ether, with (meth)acrylic acid.
  • Urethane (meth)acrylates are, in particular, the products of a reaction, likewise known to the person skilled in the art, of hydroxylalkyl (meth)acrylates with poly- or diisocyanates.
  • epoxide and urethane (meth)acrylates are included amongst the compounds listed above as “mixed forms”. If reactive thinners are used, their amount and properties must be matched to the respective conditions in such a way that, on the one hand, a satisfactory desired effect, for example the desired colour of the composition according to the invention, is achieved, but, on the other hand, the phase behaviour of the liquid-crystalline composition is not excessively impaired.
  • the low-crosslinking (high-crosslinking) liquid- crystalline compositions can be prepared, for example, using corresponding reactive thinners, which have a relatively low (high) number of reactive units per molecule.
  • the group of diluents include, for example: C1-C4-alcohols, for example methanol, ethanol, n-propanol, isopropanol, butanol, isobutanol, sec-butanol and, in particular, the C5-C12-alcohols n- pentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, n- undecanol and n-dodecanol, and isomers thereof, glycols, for example 1,2-ethylene glycol, 1,2- and 1,3-propylene glycol, 1,2-, 2,3- and 1,4- butylene glycol, di
  • these diluents can also be mixed with water.
  • suitable diluents are C1-C4-alcohols, for example methanol, ethanol, n-propanol, isopropanol, butanol, isobutanol and sec-butanol, glycols, for example 1,2-ethylene glycol, 1,2- and 1,3-propylene glycol, 1,2-, 2,3- and 1,4-butylene glycol, di- and triethylene glycol, and di- and tripropylene glycol, ethers, for example tetrahydrofuran and dioxane, ketones, for example acetone, methyl ethyl ketone and diacetone alcohol (4-hydroxy-4-methyl-2-pentanone), and C1- C4-alkyl esters, for example methyl, e
  • the diluents are optionally employed in a proportion of from about 0 to 10.0% by weight, preferably from about 0 to 5.0% by weight, based on the total weight of the polymerisable LC material.
  • the antifoams and deaerators (c1)), lubricants and flow auxiliaries (c2)), thermally curing or radiation-curing auxiliaries (c3)), substrate wetting auxiliaries (c4)), wetting and dispersion auxiliaries (c5)), hydrophobicizing agents (c6)), adhesion promoters (c7)) and auxiliaries for promoting scratch resistance (c8)) cannot strictly be delimited from one another in their action.
  • lubricants and flow auxiliaries often also act as antifoams and/or deaerators and/or as auxiliaries for improving scratch resistance.
  • Radiation-curing auxiliaries can also act as lubricants and flow auxiliaries and/or deaerators and/or as substrate wetting auxiliaries.
  • some of these auxiliaries can also fulfil the function of an adhesion promoter (c8)).
  • a certain additive can therefore be classified in a number of the groups c1) to c8) described below.
  • the antifoams in group c1) include silicon-free and silicon-containing polymers.
  • the silicon-containing polymers are, for example, unmodified or modified polydialkylsiloxanes or branched copolymers, comb or block copolymers comprising polydialkylsiloxane and polyether units, the latter being obtainable from ethylene oxide or propylene oxide.
  • the deaerators in group c1) include, for example, organic polymers, for example polyethers and polyacrylates, dialkylpolysiloxanes, in particular dimethylpolysiloxanes, organically modified polysiloxanes, for example arylalkyl-modified polysiloxanes, and fluorosilicones.
  • the action of the antifoams is essentially based on preventing foam formation or destroying foam that has already formed.
  • Antifoams essentially work by promoting coalescence of finely divided gas or air bubbles to give larger bubbles in the medium to be deaerated, for example the compositions according to the invention, and thus accelerate escape of the gas (of the air). Since antifoams can frequently also be employed as deaerators and vice versa, these additives have been included together under group c1).
  • auxiliaries are, for example, commercially available from Tego as TEGO® Foamex 800, TEGO® Foamex 805, TEGO® Foamex 810, TEGO® Foamex 815, TEGO® Foamex 825, TEGO® Foamex 835, TEGO® Foamex 840, TEGO® Foamex 842, TEGO® Foamex 1435, TEGO® Foamex 1488, TEGO® Foamex 1495, TEGO® Foamex 3062, TEGO® Foamex 7447, TEGO® Foamex 8020, Tego® Foamex N, TEGO® Foamex K 3, TEGO® Antifoam 2-18,TEGO® Antifoam 2-18, TEGO® Antifoam 2-57, TEGO® Antifoam 2-80, TEGO® Antifoam 2-82, TEGO® Antifoam 2-89, TEGO® Antifoam 2-92, TEGO® Antifo
  • the auxiliaries in group c1) are optionally employed in a proportion of from about 0 to 3.0% by weight, preferably from about 0 to 2.0% by weight, based on the total weight of the polymerisable LC material.
  • the lubricants and flow auxiliaries typically include silicon- free, but also silicon-containing polymers, for example polyacrylates or modifiers, low-molecular-weight polydialkylsiloxanes.
  • the modification consists in some of the alkyl groups having been replaced by a wide variety of organic radicals. These organic radicals are, for example, polyethers, polyesters or even long-chain (fluorinated)alkyl radicals, the former being used the most frequently.
  • polyether radicals in the correspondingly modified polysiloxanes are usually built up from ethylene oxide and/or propylene oxide units. Generally, the higher the proportion of these alkylene oxide units in the modified polysiloxane, the more hydrophilic is the resultant product.
  • auxiliaries are, for example, commercially available from Tego as TEGO® Glide 100, TEGO® Glide ZG 400, TEGO® Glide 406, TEGO® Glide 410, TEGO® Glide 411, TEGO® Glide 415, TEGO® Glide 420, TEGO® Glide 435, TEGO® Glide 440, TEGO® Glide 450, TEGO® Glide A 115, TEGO® Glide B 1484 (can also be used as antifoam and deaerator), TEGO® Flow ATF, TEGO® Flow 300, TEGO® Flow 460, TEGO® Flow 425 and TEGO® Flow ZFS 460.
  • Suitable radiation-curable lubricants and flow auxiliaries which can also be used to improve the scratch resistance, are the products TEGO® Rad 2100, TEGO® Rad 2200, TEGO® Rad 2500, TEGO® Rad 2600 and TEGO® Rad 2700, which are likewise obtainable from TEGO.
  • Such-auxiliaries are also available, for example, from BYK as BYK®-300 BYK®-306, BYK®-307, BYK®-310, BYK®-320, BYK®-333, BYK®-341, Byk® 354, Byk®361, Byk®361N, BYK®388.
  • Such-auxiliaries are also available, for example, from 3M as FC4430®.
  • Such-auxiliaries are also available, for example, from Cytonix as FluorN®561 or FluorN®562. Such-auxiliaries are also available, for example, from Merck KGaA as Tivida® FL 2300 and Tivida® FL 2500
  • the auxiliaries in group c2) are optionally employed in a proportion of from about 0 to 3.0% by weight, preferably from about 0 to 2.0% by weight, based on the total weight of the polymerisable LC material.
  • the radiation-curing auxiliaries include, in particular, polysiloxanes having terminal double bonds which are, for example, a constituent of an acrylate group. Such auxiliaries can be crosslinked by actinic or, for example, electron radiation.
  • auxiliaries generally combine a number of properties together.
  • they can act as antifoams, deaerators, lubricants and flow auxiliaries and/or substrate wetting auxiliaries, while, in the crosslinked state, they increase, in particular, the scratch resistance, for example of coatings or films which can be produced using the compositions according to the invention.
  • the improvement in the gloss properties, for example of precisely those coatings or films, is regarded essentially as a consequence of the action of these auxiliaries as antifoams, deaerators and/or lubricants and flow auxiliaries (in the uncrosslinked state).
  • suitable radiation-curing auxiliaries are the products TEGO® Rad 2100, TEGO® Rad 2200, TEGO® Rad 2500, TEGO® Rad 2600 and TEGO® Rad 2700 available from TEGO and the product BYK®-371 available from BYK.
  • Thermally curing auxiliaries in group c3) contain, for example, primary OH groups, which are able to react with isocyanate groups, for example of the binder.
  • thermally curing auxiliaries, which can be used are the products BYK®-370, BYK®-373 and BYK®-375 available from BYK.
  • the auxiliaries in group c3) are optionally employed in a proportion of from about 0 to 5.0% by weight, preferably from about 0 to 3.0% by weight, based on the total weight of the polymerisable LC material.
  • the substrate wetting auxiliaries in group c4) serve, in particular, to increase the wettability of the substrate to be printed or coated, for example, by printing inks or coating compositions, for example compositions according to the invention.
  • the generally attendant improvement in the lubricant and flow behaviour of such printing inks or coating compositions has an effect on the appearance of the finished (for example crosslinked) print or coating.
  • auxiliaries are commercially available, for example from Tego as TEGO® Wet KL 245, TEGO® Wet 250, TEGO® Wet 260 and TEGO® Wet ZFS 453 and from BYK as BYK®-306, BYK®-307, BYK®-310, BYK®-333, BYK®-344, BYK®-345, BYK®-346 and Byk®-348.
  • the auxiliaries in group c4) are optionally employed in a proportion of from about 0 to 3.0% by weight, preferably from about 0 to 1.5% by weight, based on the total weight of the liquid-crystalline composition.
  • the wetting and dispersion auxiliaries in group c5) serve, in particular, to prevent the flooding and floating and the sedimentation of pigments and are therefore, if necessary, suitable in particular in pigmented compositions. These auxiliaries stabilize pigment dispersions essentially through electrostatic repulsion and/or steric hindrance of the pigment particles containing these additives, where, in the latter case, the interaction of the auxiliary with the ambient medium (for example binder) plays a major role. Since the use of such wetting and dispersion auxiliaries is common practice, for example in the technical area of printing inks and paints, the selection of a suitable auxiliary of this type generally does not present the person skilled in the art with any difficulties, if they are used.
  • Such wetting and dispersion auxiliaries are commercially available, for example from Tego, as TEGO® Dispers 610, TEGO® Dispers 610 S, TEGO® Dispers 630, TEGO® Dispers 700, TEGO® Dispers 705, TEGO® Dispers 710, TEGO® Dispers 720 W, TEGO® Dispers 725 W, TEGO® Dispers 730 W, TEGO® Dispers 735 W and TEGO® Dispers 740 W and from BYK as Disperbyk®, Disperbyk®-107, Disperbyk®-108, Disperbyk®- 110, Disperbyk®-111, Disperbyk®-115, Disperbyk®-130, Disperbyk®-160, Disperbyk®-161, Disperbyk®-162, Disperbyk®-163, Disperbyk®-164, Disperbyk®-165, Disperbyk®-166, Disperbyk®-167, Disperbyk®-170, Dis
  • the amount of the auxiliaries in group c5) used on the mean molecular weight of the auxiliary can be used to give water- repellent properties to prints or coatings produced, for example, using compositions according to the invention. This prevents or at least greatly suppresses swelling due to water absorption and thus a change in, for example, the optical properties of such prints or coatings.
  • the composition when used, for example, as a printing ink in offset printing, water absorption can thereby be prevented or at least greatly reduced.
  • Such hydrophobicizing agents are commercially available, for example, from Tego as Tego® Phobe WF, Tego® Phobe 1000, Tego® Phobe 1000 S, Tego® Phobe 1010, Tego® Phobe 1030, Tego® Phobe 1010, Tego® Phobe 1010, Tego® Phobe 1030, Tego® Phobe 1040, Tego® Phobe 1050, Tego® Phobe 1200, Tego® Phobe 1300, Tego® Phobe 1310 and Tego® Phobe 1400.
  • auxiliaries in group c6) are optionally employed in a proportion of from about 0 to 5.0% by weight, preferably from about 0 to 3.0% by weight, based on the total weight of the polymerisable LC material.
  • Further adhesion promoters from group c7) serve to improve the adhesion of two interfaces in contact. It is directly evident from this that essentially the only fraction of the adhesion promoter that is effective is that located at one or the other or at both interfaces.
  • adhesion promoter must be added directly to the latter or the substrate must be pre-treated with the adhesion promoters (also known as priming), i.e. this substrate is given modified chemical and/or physical surface properties.
  • adhesion promoters also known as priming
  • this substrate is given modified chemical and/or physical surface properties.
  • the substrate has previously been primed with a primer, this means that the interfaces in contact are that of the primer on the one hand and of the printing ink or coating composition or paint on the other hand.
  • the adhesion properties between the substrate and the primer but also between the substrate and the printing ink or coating composition or paint play a part in adhesion of the overall multilayer structure on the substrate.
  • Adhesion promoters in the broader sense which may be mentioned are also the substrate wetting auxiliaries already listed under group c4), but these generally do not have the same adhesion promotion capacity.
  • the multiplicity of adhesion promoter systems is not surprising.
  • Adhesion promoters based on silanes are, for example, 3- aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- aminopropylmethyldiethoxysilane, N-aminoethyl-3- aminopropyltrimethoxysilane, N-aminoethyl-3- aminopropylmethyldimethoxysilane, N-methyl-3- aminopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, 3- methacryloyloxypropyltrimethoxysilane, 3- glycidyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3- chloropropyltrimethoxysilane and vinyltrimethoxysilane.
  • the auxiliaries for improving the scratch resistance in group c8) include, for example, the abovementioned products TEGO® Rad 2100, TEGO® Rad 2200, TEGO® Rad 2500, TEGO® Rad 2600 and TEGO® Rad 2700, which are available from Tego.
  • the amount data given for group c3) are likewise suitable, i.e. these additives are optionally employed in a proportion of from about 0 to 5.0% by weight, preferably from about 0 to 3.0% by weight, based on the total weight of the liquid-crystalline composition.
  • alkylated monophenols such as 2,6-di-tert-butyl-4-methylphenol, 2-tert- butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4- n-butylphenol, 2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4- methylphenol, 2-( ⁇ -methylcyclohexyl)-4,6-dimethylphenol, 2,6-dioctadecyl- 4-methylphenol, 2,4,6-tricyclohexylphenol, 2,6-di-tert-butyl-4- methoxymethylphenol, nonylphenols which have a linear or branched side chain, for example 2,6-dinonyl-4-methylphenol, 2,4-dimethyl-6
  • the polymerisable LC material comprises one or more specific antioxidant additives, preferably selected from the Irganox® series, e.g. the commercially available antioxidants Irganox®1076 and Irganox®1010, from Ciba, Switzerland.
  • the polymerisable LC material comprises a combination of one or more, more preferably of one or two photoinitiators, for example, selected from the commercially available Irgacure® or Darocure® (Ciba AG) series, in particular, Irgacure 127, Irgacure 184, Irgacure 369, Irgacure 651, Irgacure 817, Irgacure 907, Irgacure 1300, Irgacure, Irgacure 2022, Irgacure 2100, Irgacure 2959, or Darcure TPO, further selected from the commercially available OXE02 (Ciba AG), NCI 930, N1919T (Adeka), SPI-03 or SPI-04 (Samyang), or preferably combinations thereof, such as SPI-03 and NCI-930.
  • Irgacure® or Darocure® Ciba AG
  • the concentration of the polymerisation initiator(s) as a whole in the polymerisable LC material is preferably from 0.5 to 5%, very preferably from 0.5 to 3%, more preferably 1 to 2%.
  • the polymerisable LC material comprises besides one or more compounds of formula UVI and one or more compound of formula TRI, a) one or more di- or multireactive polymerisable mesogenic compounds, b) optionally one or more monoreactive polymerisable mesogenic compounds, c) optionally one or more antioxidative additives, d) optionally one or more adhesion promotors, e) optionally one or more surfactants, f) optionally one or more mono-, di- or multireactive polymerisable non-mesogenic compounds, g) optionally one or more dyes showing an absorption maximum at the wavelength used to initiate photo polymerisation, h) optionally one or more chain transfer agents, i) optionally one or more stabilizers, j) optionally one or more lubric
  • the polymerisable LC material comprises, a) one or more compounds of formula UVI, b) one or more compound of formula TRI, c) one or more, preferably two or more, direactive polymerisable mesogenic compounds, preferably in an amount, if present at all, of 10 to 90 % by weight, very preferably 15 to 75 % by weight, preferably selected from the compounds of formula DRMa-1, d) optionally one or more, preferably two or more, monoreactive polymerisable mesogenic compounds, preferably in an amount of 10 to 95 % by weight, very preferably 25 to 85 %, preferably selected from compounds of formulae MRM-1 and/or MRM-7, e) optionally one or more compounds of formula ND in the preferably in an amount of 1 to 50 %, very preferably from 1 to 40 %.
  • optionally one or more antioxidative additives preferably selected from esters of unsubstituted and substituted benzoic acids, in particular Irganox®1076, and if present, preferably in an amount of 0.01 to 2 % by weight, very preferably 0.05 to 1 % by weight
  • optionally one or more lubricants and flow auxiliaries preferably selected from BYK®388, FC 4430, Fluor N 561 and/or Fluor N 562, and if present, preferably in an amount of 0.1 to 5 % by weight, very preferably 0.2 to 3 % by weight
  • optionally one or more photoinitiators optionally one or more photoinitiators.
  • the invention further relates to a method of preparing a polymer film by - providing a layer of a polymerisable LC material as described above and below onto a substrate, - polymerising the polymerisable components of the polymerisable LC material by photopolymerisation, and - optionally removing the polymerised LC material from the substrate and/or optionally providing it onto another substrate. It is also possible to dissolve the polymerisable LC material in a suitable solvent.
  • the polymerisable LC material comprises one or more solvents, which are preferably selected from organic solvents.
  • the solvents are preferably selected from ketones such as acetone, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone or cyclohexanone; acetates such as methyl, ethyl or butyl acetate or methyl acetoacetate; alcohols such as methanol, ethanol or isopropyl alcohol; aromatic solvents such as toluene or xylene; alicyclic hydrocarbons such as cyclopentane or cyclohexane; halogenated hydrocarbons such as di- or trichloromethane; glycols or their esters such as PGMEA (propyl glycol monomethyl ether acetate), ⁇ -butyrolactone.
  • ketones such as acetone, methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone or cyclohexanone
  • acetates such
  • the polymerisable LC material contains one or more solvents
  • the total concentration of all solids, including the RMs, in the solvent(s) is preferably from 10 to 60%.
  • This solution is then coated or printed onto the substrate, for example by spin-coating, printing, or other known techniques, and the solvent is evaporated off before polymerisation. In most cases, it is suitable to heat the mixture in order to facilitate the evaporation of the solvent.
  • the polymerisable LC material can be applied onto a substrate by conventional coating techniques like spin coating, bar coating or blade coating.
  • Suitable substrate materials and substrates are known to the expert and described in the literature, as for example conventional substrates used in the optical films industry, such as glass or plastic.
  • polyester such as polyethyleneterephthalate (PET) or polyethylenenaphthalate (PEN), polyvinylalcohol (PVA), polycarbonate (PC) triacetylcellulose (TAC), or cyclo olefin polymers (COP), or commonly known color filter materials, in particular triacetylcellulose (TAC), cyclo olefin polymers (COP), or commonly known colour filter materials.
  • PET polyethyleneterephthalate
  • PEN polyethylenenaphthalate
  • PVA polyvinylalcohol
  • PC polycarbonate
  • TAC triacetylcellulose
  • COP cyclo olefin polymers
  • color filter materials in particular triacetylcellulose (TAC), cyclo olefin polymers (COP), or commonly known colour filter materials.
  • the polymerisable LC material preferably exhibits a uniform alignment throughout the whole layer.
  • the polymerisable LC material exhibits a uniform planar or a uniform homeotropic alignment.
  • the Friedel-Creagh-Kmetz rule can be used to predict whether a mixture will adopt planar or homeotropic alignment, by comparing the surface energies of the RM layer and the substrate: If ⁇ RM > ⁇ s the reactive mesogenic compounds will display homeotropic alignment, If ⁇ RM ⁇ ⁇ s the reactive mesogenic compounds will display homogeneous alignment.
  • the surface energy of a substrate is relatively low, the intermolecular forces between the reactive mesogens are stronger than the forces across the RM-substrate interface. Therefore, reactive mesogens align perpendicular to the substrate (homeotropic alignment) in order to maximise the intermolecular forces.
  • Homeotropic alignment can also be achieved by using amphiphilic materials; they can be added directly to the polymerisable LC material, or the substrate can be treated with these materials in the form of a homeotropic alignment layer.
  • the polar head of the amphiphilic material chemically bonds to the substrate, and the hydrocarbon tail points perpendicular to the substrate. Intermolecular interactions between the amphiphilic material and the RMs promote homeotropic alignment. Commonly used amphiphilic surfactants are described above.
  • Another method used to promote homeotropic alignment is to apply corona discharge treatment to plastic substrates, generating alcohol or ketone functional groups on the substrate surface. These polar groups can interact with the polar groups present in RMs or surfactants to promote homeotropic alignment.
  • planar alignment is by coating the substrate with a polyimide layer, and then rubbing the alignment layer with a velvet cloth.
  • suitable planar alignment layers are known in the art, like for example rubbed polyimide or alignment layers prepared by photoalignment as described in US 5,602,661, US 5,389,698 or US 6,717,644. In general, reviews of alignment techniques are given for example by I. Sage in "Thermotropic Liquid Crystals", edited by G. W.
  • the polymerisable compounds in the polymerisable LC material are polymerised or crosslinked (if one compound contains two or more poly- merisable groups) by in-situ photopolymerisation.
  • the photopolymerisation can be carried out in one step.
  • the polymerisable LC material is coated onto a substrate and subsequently photopolymerised for example by exposure to actinic radiation as described for example in WO 01/20394, GB 2,315,072 or WO 98/04651.
  • Photopolymerisation of the LC material is preferably achieved by exposing it to actinic radiation.
  • Actinic radiation means irradiation with light, like UV light, IR light or visible light, irradiation with X-rays or gamma rays, or irradiation with high-energy particles, such as ions or electrons.
  • polymerisation is carried out by photo irradiation, in particular with UV light.
  • a source for actinic radiation for example a single UV lamp or a set of UV lamps can be used. When using a high lamp power the curing time can be reduced.
  • Another possible source for photo radiation is a laser, like e.g. a UV laser, an IR laser, or a visible laser.
  • the curing time is dependent, inter alia, on the reactivity of the polymerisable LC material, the thickness of the coated layer, the type of polymerisation initiator and the power of the UV lamp.
  • the curing time is preferably ⁇ 5 minutes, very preferably ⁇ 3 minutes, most preferably ⁇ 1 minute.
  • a suitable UV radiation power is preferably in the range from 5 to 200 mWcm-2, more preferably in the range from 50 to 175 mWcm -2 and most preferably in the range from 100 to 150 mWcm -2 .
  • a suitable UV dose is preferably in the range from 25 to 7200 mJcm -2 more preferably in the range from 500 to 7200 mJcm -2 and most preferably in the range from 3000 to 7200 mJcm -2 .
  • Photopolymerisation is preferably performed under an inert gas atmosphere, preferably in a heated nitrogen atmosphere, but also polymerisation in air is possible.
  • Photopolymerisation is preferably performed at a temperature from 1 to 70°C, more preferably 5 to 50°C, even more preferably 15 to 30°C.
  • the polymerised LC film according to the present invention has good adhesion to plastic substrates, in particular to TAC, COP, and colour filters. Accordingly, it can be used as adhesive or base coating for subsequent LC layers which otherwise would not well adhere to the substrates.
  • the preferred thickness of a polymerised LC film according to the present invention is determined by the optical properties desired from the film or the final product. For example, if the polymerised LC film does not mainly act as an optical layer, but e.g.
  • uniformly homeotropic or planar aligned polymer films of the present invention can be used as retardation or compensation films for example in LCDs to improve the contrast and brightness at large viewing angles and reduce the chromaticity. They can be used outside the switchable liquid-crystalline cell in an LCD, or between the substrates, usually glass substrates, forming the switchable liquid-crystalline cell and containing the switchable liquid-crystalline medium (in cell application).
  • the polymer film preferably has a thickness of from 0.5 to 10 ⁇ m, very preferably from 0.5 to 5 ⁇ m, in particular from 0.5 to 3 ⁇ m.
  • the birefringence as a function of the direction of the incident beam is defined as wherein sin ⁇ ⁇ is the incidence angle or the tilt angle of the optical axis in the film and sin ⁇ ⁇ is the corresponding ⁇ reflection angle.
  • the birefringence and accordingly optical retardation depends on the thickness of a film and the tilt angle of optical axis in the film (cf. Berek’s compensator). Therefore, the skilled expert is aware that different optical retardations or different birefringence can be induced by adjusting the orientation of the liquid-crystalline molecules in the polymer film.
  • the birefringence ( ⁇ n) of the polymer film according to the present invention is preferably in the range from 0.01 to 0.30, more preferable in the range from 0.01 to 0.25 and even more preferable in the range from 0.01 to 0.16.
  • the optical retardation as a function of the thickness of the polymer film according to the present invention is less than 200 nm, preferable less than 180 nm and even more preferable less than 150 nm.
  • the polymer film of the present invention can also be used as alignment film for other liquid-crystalline or RM materials. For example, they can be used in an LCD to induce or improve alignment of the switchable liquid- crystalline medium, or to align a subsequent layer of polymerisable LC material coated thereon.
  • the polymerised LC films and polymerisable LC materials according to the present invention are useful in optical elements like polarisers, compensators, alignment layer, circular polarisers or colour filters in liquid crystal displays or projection systems, decorative images, for the preparation of liquid crystal or effect pigments, and especially in reflective films with spatially varying reflection colours, e.g. as multicolour image for decorative, information storage or security uses, such as non- forgeable documents like identity or credit cards, banknotes etc..
  • the polymerised LC films according to the present invention can be used in displays of the transmissive or reflective type.
  • LCDs can be used in conventional OLED displays or LCDs, in particular LCDs of the DAP (deformation of aligned phases) or VA (vertically aligned) mode, like e.g. ECB (electrically controlled birefringence), CSH (colour super homeotropic), VAN or VAC (vertically aligned nematic or cholesteric) displays, MVA (multi-domain vertically aligned) or PVA (patterned vertically aligned) displays, in displays of the bend mode or hybrid type displays, like e.g.
  • DAP deformation of aligned phases
  • VA vertical aligned
  • ECB electrically controlled birefringence
  • CSH colour super homeotropic
  • VAN or VAC vertically aligned nematic or cholesteric
  • MVA multi-domain vertically aligned
  • PVA patterned vertically aligned
  • OCB optically compensated bend cell or optically compensated birefringence
  • R-OCB reflective OCB
  • HAN hybrid aligned nematic
  • pi-cell ⁇ -cell
  • displays of the TN (twisted nematic), HTN (highly twisted nematic) or STN (super twisted nematic) mode in AMD-TN (active matrix driven TN) displays, or in displays of the IPS (in plane switching) mode which are also known as 'super TFT' displays.
  • VA MVA
  • PVA OCB
  • pi-cell displays furthermore in displays of the TN (twisted nematic), HTN (highly twisted nematic) or STN (super twisted nematic) mode
  • VA MVA
  • PVA OCB
  • pi-cell displays Especially preferred are Especially preferred.
  • the polymerisable LC material and polymer films according to the present invention are especially useful for a 3D display as described in EP 0829 744, EP 0887666 A2, EP 0887692, US 6,046,849, US 6,437,915 and in "Proceedings o the SID 20 th International Display Research Conference, 2000", page 280.
  • a 3D display of this type comprising a polymer film according to the invention is another object of the present invention.
  • the present invention is described above and below with particular reference to the preferred embodiments. It should be understood that various changes and modifications might be made therein without departing from the spirit and scope of the invention. Many of the compounds or mixtures thereof mentioned above and below are commercially available.
  • Axoscan ellipsometer is used to determine the initial retardation and dispersion.
  • the film is then stressed with Suntest XLS+ (430W/m 2 ) at 63°C up to 204 hrs. After the test the retardation profile and dispersion is determined again.
  • the durability is quantified by the difference in retardation ( ⁇ R in ) and/or the dispersion (R 450 / 550 ) before and after the UV test.
  • Example 1 The following mixture M1 is prepared in accordance with the following table: The mixture M1 is dissolved, coated and cured as described above and the change in retardation and dispersion is determined before after the stress test. The results are summarized in the following table: Stressed for 204 h:
  • Example 2 The following mixture M2 is prepared in accordance with the following table: The mixture M2 is dissolved, coated and cured as described above and the change in retardation and dispersion is determined before after the stress test. The results are summarized in the following table: Stressed for 204 h:

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  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
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Abstract

L'invention concerne un matériau polymérisable à cristaux liquides, comprenant un ou plusieurs composés mésogènes diréactifs ou multiréactifs, un ou plusieurs composés de formule (UVI), (formule UVI) et un ou plusieurs composés de formule TRI (formule TRI), les radicaux individuels présentant l'une des significations données dans les revendications. De plus, l'invention concerne également un procédé pour sa préparation, un film polymère, présentant des propriétés améliorées de durabilité thermique et de stabilité aux UV, pouvant être obtenu à partir d'un matériau polymérisable à cristaux liquides correspondant, un procédé de préparation d'un tel film polymère et l'utilisation d'un tel film polymère et dudit matériau polymérisable à cristaux liquides pour des dispositifs optiques, électro-optiques, décoratifs ou de sécurité.
PCT/EP2021/066752 2020-06-23 2021-06-21 Matériau polymérisable à cristaux liquides et film polymérisé à cristaux liquides WO2021259825A1 (fr)

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