Polymerizable liquid crystal ink formulations

Abstract

The present invention relates to polymerizable liquid crystal formulations, in particular to ink formulations for ink jet printing comprising 10 to 50% w / w of one or more polymerizable liquid crystal compounds and 50 to 90% w / w of one or more organic solvents, the organic solvent is selected from aliphatic ketone, cyclic ketone, alkyl ether of ethylene glycol or propylene glycol, alkyl ester of menthyl or aromatic solvent.

Description

[0001] This application is a divisional application of patent application with application number 201980082266.6. Technical Field

[0002] The present invention relates to a polymerizable liquid crystal formulation, in particular to an ink formulation for inkjet printing, comprising 10 to 50% w / w of one or more polymerizable liquid crystal compounds and 50 to 90% w / w of one or more organic solvents selected from aliphatic ketones, cyclic ketones, alkyl ethers of ethylene glycol or propylene glycol, alkyl esters of menthyl or aromatic solvents.

[0003] Background and Prior Art

[0004] Flat LCDs exhibit good image quality, low cost, and good processability over large area sizes, thanks to a well-established supply chain for all of their components. However, brightness and color gamut are generally inferior compared to light-emitting diode (LED) and organic light-emitting diode displays (OLED). The larger layout of polarizers, absorptive color filters, and optical films present in LCD panels compared to OLED panels is the primary reason for the lower transmission and color purity of LCD displays, ultimately resulting in lower power efficiency of the device. For reference, only about 30% of the light emitted from the backlight element is experienced by the user because it is blocked or absorbed by the LCD panel.

[0005] JP 4752581 B2 proposes an improved method for manufacturing a color filter, which has a process of forming a barrier material on a substrate; a process of forming a plurality of color pixel patterns with a certain delay between the barrier materials by a photolithography method; a process of forming an alignment film processed by an alignment treatment on the color pixel pattern; and a process of forming a liquid crystal phase shift layer on the alignment film by an inkjet method with each delay corresponding to the plurality of color pixel patterns, wherein the liquid crystal phase shift layer includes a plurality of liquid crystal phase shift regions corresponding to the plurality of color patterns; the plurality of liquid crystal phase shift regions have a delay, which corrects the delay of the plurality of color pixel patterns; and the sum of the delays of the plurality of color pixel patterns and the delays of the corresponding plurality of liquid crystal phase shift regions is characteristic and substantially the same for each pixel.

[0006] However, the proposed process requires additional processing steps in terms of known mass production methods, such as a process of forming a barrier material on a substrate by a photolithography method.

[0007] Other attempts to improve light efficiency have been reported for LCD panels without color filters.Such displays have a backlight element comprising a plurality of white, red, green and blue light emitting diodes arranged on a substrate, as described, for example, in US 8,928,841 B2.

[0008] For example, KR 10-0946015 B1 describes a backlight element containing phosphor-converted white LEDs, the blue light emitted by which is converted by the phosphor material into yellow radiation to provide the resulting white light.

[0009] However, the broad bandwidth of the converted yellow light creates an important limitation, preventing high brightness and high color gamut due to the absorption of light by the color filters. Therefore, narrow bandwidth RGB emitters are the preferred option to improve the color gamut by avoiding parallax effects and improving the overall brightness of LCD displays.

[0010] In this regard, quantum materials (QM) are very suitable to solve the above shortcomings because they have the following outstanding characteristics:

[0011] Their central emission wavelength can be tuned by controlling the size of the nanoparticles,

[0012] Their FWHM is about 20-30 nm, which is mainly determined by size,

[0013] Their photoluminescence efficiency is high, and

[0014] The resulting device is simple to configure.

[0015] On the one hand, these properties make them good candidates for replacing phosphor materials in backlight units, as described, for example, in Adv. Mater. 2010, Vol. 22, pp. 3076-3080, and on the other hand, these properties also make them good candidates for replacing conventional absorptive color filters, as described, for example, in CN 102944943 B. Both solutions enable LCD displays to have high transmission and color gamut, resulting in brilliant image quality, provided the color of the light is converted as desired.

[0016] Optical films or for example optical retarders, brightness enhancement films or reflective optical films based on polymerizable liquid crystals are described in EP 0 940 707 B1, EP 0 888 565 B1 and GB 2 329 393 B1. Their high birefringence, favorable alignment control and well-established processing in large-scale production make them excellent materials for improving the performance of displays.

[0017] The common large-scale production method for these membranes involves the following steps:

[0018] - providing a continuous layer of polymerisable LC material on the substrate, for example by inkjet printing,

[0019] - polymerising a polymerisable component of the polymerisable LC material by photopolymerisation, and

[0020] - optionally removing the polymerized LC material from the substrate, and / or optionally providing it on another substrate.

[0021] As a result of the above-described process, the optical film based on polymerizable liquid crystals or reactive mesogens (RMs) forms a continuous film, which is provided in a display layout as a single layer with a significant thickness over the entire layer.

[0022] The optical retardation (δ(λ)) of such a polymer film as a function of the wavelength (λ) of the incident light beam is given by the following formula:

[0023] δ(λ)=(2πΔn·d) / λ

[0024] where (Δn) is the birefringence of the film, (d) is the thickness of the film, and λ is the wavelength of the incident light.

[0025] Therefore, the optical retardation of a given polymeric liquid crystal film is constant in the xy plane. However, ideally, for each sub-pixel (RGB), each color would need to have different optical properties in the xy plane of the polymer film. Alternatively, cholesteric optical films are often used to increase the brightness of the device, however, here too each color would need a polymer film with different optical reflectance.

[0026] Inkjet printing is a manufacturing technique used to deposit inks or materials onto a variety of substrates with micron-level precision (e.g., sub-pixel dimensions). It can be used to produce complex patterns that can otherwise only be produced through more complex, multi-step processes using photomasks (e.g., patterned retarders). In addition, it offers the potential for digitization of manufacturing processes, which are currently limited to processes such as roll-to-roll large-area substrates. In addition, inkjet printing can be used to apply specific materials to specific locations on a given substrate, or to achieve pixel-to-pixel printing.

[0027] A general challenge of inkjet printing is controlling the thickness profile of the dry deposition, as described, for example, in J. Sun, B. Bao, M. He, H. Zhou and Y. Song, ACS Appl. Mater. Interfaces, 2015, 7, 28086-28099 or P. Calvert, Chem. Mater., 2001, 13, 3299-3305.

[0028] One common profile observed when inkjet printing solids from solvents is the coffee ring effect, as further described in D. Mampallil and HB Eral, Adv. Colloid Interface Sci., 2018, 252, 38-54; W. Han and Z. Lin, Angew. Chemie-Int. Ed., 2012, 51, 1534-1546 or RD Deegan, O. Bakajin, TF Dupont, G. Huber, SR Nagel and TA Witten, Nature, 1997, 389, 827-829.

[0029] The solvent then becomes depleted at the edge, and the solvent in the center of the drying droplet is driven to the edge. This solvent carries the solute with it and leaves behind an outline of the material that has accumulated at the edge after complete evaporation.

[0030] For non-polymerizable liquid crystal formulations, such as printing inks for OLED applications, methods for solving the coffee ring effect problem are described, such as the use of mixed solvent systems and surfactants, such as described in T. Still, PJ Yunker and A. G. Yodh, Langmuir, 2012, 28, 4984-4988 or C. Jiang, Z. Zhong, B. Liu, Z. He, J. Zou, L. Wang, J. Wang, J. Peng and Y. Cao, ACS Appl. Mater. Interfaces, 2016, 8, 26162-26168. In addition to these solutions, D. Soltman and V. Subramanian, Langmuir, 2008, 24, 2224-2231 proposed reducing the evaporation rate to prevent this unwanted transport of solutes.

[0031] However, considering the polymerizable liquid crystal formulation, the smooth surface profile and high alignment quality of the liquid crystal molecules are necessary for the inkjet printed optical film to produce good optical properties. In addition, the inventors have also found that the non-polymerizable liquid crystal formulations commonly used in inks and solvent systems based on high boiling point solvents (such as γ-butyrolactone, cyclohexylbenzene, butyl benzoate, methyl benzoate, 1-methylnaphthalene, etc.) are not suitable for use with polymerizable liquid crystal mixtures because of the long time required for their evaporation. These long evaporation times usually result in poor alignment quality of the inkjet printed polymer film obtained from the polymerizable liquid crystal formulation.

[0032] In addition, common solvents used in polymerizable liquid crystal mixtures (such as cyclohexanone, toluene, cyclopentanone, PGMEA, MIBK, etc.) are not suitable for inkjet printing technology due to the very fast evaporation rate of the solvent, which hinders the use of inkjet technology. Generally, the above-mentioned low boiling point solvents are usually not suitable for inkjet printing because the volume of each drop of solvent is much smaller than the standard coating volume. This leads to evaporation and subsequent crystallization on the print head, hindering further printing.

[0033] In view of these problems, there is a great need for polymerizable liquid crystal mixtures or ink formulations based on high boiling point solvent systems, which formulations, in addition to one or more polymerizable liquid crystal compounds, also contain one or more solvents for inkjet printing applications, which solvents preferably exhibit a slow evaporation rate and a high annealing temperature. In addition, the polymer film obtained from such a formulation by inkjet printing should exhibit good alignment quality after polymerization, even when printed on small areas, such as typical pixel or sub-pixel sizes.

[0034] Surprisingly, the present inventors have discovered that a certain series of solvents and solvent combinations, in combination with polymerizable liquid crystal materials, exhibit very good jetting performance while also achieving high resolution and a flat print profile. Summary of the invention

[0035] The present invention therefore relates to an ink formulation for inkjet printing comprising 10 to 50% w / w of one or more polymerizable liquid crystal compounds and 50 to 90% w / w of one or more organic solvents selected from aliphatic ketones, cyclic ketones, alkyl ethers of ethylene glycol or propylene glycol, alkyl esters of menthyl or aromatic solvents.

[0036] Further, the present invention relates to a method for producing an ink formulation by mixing at least 10 to 50% w / w of one or more polymerizable liquid crystal compounds with 50 to 90% w / w of one or more solvents selected from aliphatic ketones, cyclic ketones, alkyl ethers of ethylene glycol or propylene glycol or aromatic solvents.

[0037] Further, the present invention relates to the use of an ink formulation as described above and below in an inkjet printer.

[0038] Further, the present invention relates to a polymer film obtainable or obtained by inkjet printing an ink formulation as described above and below on a substrate and curing the ink formulation.

[0039] Further, the present invention relates to a method for producing a polymer film comprising the steps of inkjet printing an ink formulation as described above and below on a substrate and curing the ink formulation.

[0040] Further, the present invention relates to the use of a polymer film as described above and below as an optical film or in an optical component.

[0041] Further, the present invention relates to an optical component comprising one or more polymer films obtainable or obtained from an ink formulation as described above and below.

[0042] Another aspect of the invention is the use of one or more optical components as described above in an optical device.

[0043] Another aspect of the present invention is an optical device comprising one or more optical components comprising one or more polymer films obtainable or obtained from the ink formulations as described above and below.

[0044] Details

[0045] The present invention relates to a polymerizable liquid crystal ink formulation for inkjet printing, comprising 10 to 50% w / w of one or more polymerizable liquid crystal compounds and 50 to 90% w / w of one or more organic solvents selected from aliphatic ketones, cyclic ketones, alkyl ethers of ethylene glycol or propylene glycol, alkyl esters of menthyl or aromatic solvents.

[0046] Preferably, the one or more polymerizable liquid crystal compounds used in the ink formulation according to the present invention are selected from di- or poly-reactive compounds of the formula DRM:

[0047] P 1 -Sp 1 -MG-Sp 2 -P 2 DRM

[0048] in

[0049] P 1 and P 2 independently of one another represent a polymerizable group,

[0050] Sp 1 and Sp 2 are independently a spacer group or a single bond, and

[0051] MG is a rod-shaped mesogenic group, which is preferably selected from the formula MG

[0052] -(A 1 -Z 1 ) n -A 2 -MG

[0053] in

[0054] A 1 and A 2In the case of multiple occurrences, independently of one another, represents an aromatic or alicyclic radical, which optionally contains one or more heteroatoms selected from N, O and S and is optionally replaced by L. 1 Single or multiple substitutions,

[0055] L 1 Is P-Sp-, F, Cl, Br, I, -CN, -NO 2 , -NCO, -NCS, -OCN, -SCN, -C(=O)NR 00 R 000 、-C(=O)OR 00 、-C(=O)R 00 、-NR 00 R 000 , -OH, -SF 5 , optionally substituted silyl, aryl or heteroaryl having 1 to 12, preferably 1 to 6 C atoms, and straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12, preferably 1 to 6 C atoms, wherein one or more H atoms are optionally replaced by F or Cl,

[0056] R 00 and R 000 independently of one another represent H or an alkyl radical having 1 to 12 C atoms,

[0057] Z 1 In the case of multiple occurrences, independently of one another, they represent -O-, -S-, -CO-, -COO-, -OCO-, -S-CO-, -CO-S-, -O-COO-, -CO-NR 00 -、-NR 00 -CO-、-NR 00 -CO-NR 000 、-NR 00 -CO-O-, -O-CO-NR 00 -、-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 ) n1 , -CF 2 CH 2 -、-CH 2 CF2 -、-CF 2 CF 2 -, -CH=N-, -N=CH-, -N=N-, -CH=CR 00 -、-CY 1 =CY 2 -, -C≡C-, -CH=CH-COO-, -OCO-CH=CH- or a single bond,

[0058] Y 1 and Y 2 independently of one another represent H, F, Cl or CN,

[0059] n is 1, 2, 3 or 4, preferably 1 or 2, most preferably 2,

[0060] n1 is an integer of 1 to 10, preferably 1, 2, 3 or 4.

[0061] The "polymerizable group" (P) is preferably selected from groups containing a C=C double bond or a C≡C triple bond, and groups suitable for ring-opening polymerization, for example, oxetanyl and epoxy groups.

[0062] Preferably, the polymerizable group (P) is selected from: CH 2 =CW 1 -COO-、CH 2 =CW 1 -CO-,

[0063]

[0064] CH 2 =CW 2 -(O) k3 -、CW 1 =CH-CO-(O) k3 -、CW 1 =CH-CO-NH-, CH 2 =CW 1 -CO-NH-,

[0065] CH 3 -CH=CH-O-, (CH 2 =CH) 2 CH-OCO-, (CH 2 =CH-CH 2 ) 2 CH-OCO-,

[0066] (CH 2 =CH) 2 CH-O-, (CH 2 =CH-CH 2 ) 2N-, (CH 2 =CH-CH 2 ) 2 N-CO-、CH 2 =CW 1 -CO-NH-, CH 2 =CH-(COO) k1 -Phe-(O) k2 -、CH 2 =CH-(CO) k1 -Phe-(O) k2 -, Phe-CH=CH-,

[0067] in

[0068] W 1 Indicates H, F, Cl, CN, CF 3 , phenyl or alkyl having 1 to 5 C atoms, in particular H, F, Cl or CH 3 ,

[0069] W 2 represents H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl,

[0070] W 3 and W 4 Each independently of one another represents H, Cl or an alkyl radical having 1 to 5 C atoms, Phe represents 1,4-phenylene, which is optionally substituted by one or more radicals L as defined above but different from P-Sp, preferably, the preferred substituents L are F, Cl, CN, NO 2 , CH 3 , C 2 H 5 、OCH 3 , OC 2 H 5 、COCH 3 、COC 2 H 5 、COOCH 3 、COOC 2 H 5 CF 3 、OCF 3 , OCHF 2 , OC 2 F 5 , and phenyl, and

[0071] k 1 , k 2 and k 3 Each independently represents 0 or 1, k 3 Preferably represents 1, and k 4is an integer from 1 to 10.

[0072] A particularly preferred polymerizable group P is CH 2 =CH-COO-, CH 2 =C(CH 3 )-COO-、CH 2 =CF-COO-, CH 2 =CH-, CH 2 =CH-O-, (CH 2 =CH) 2 CH-OCO-, (CH 2 =CH) 2 CH-O-,

[0073]

[0074] Where W 2 represents H or alkyl having 1 to 5 C atoms, in particular H, methyl, ethyl or n-propyl,

[0075] Further preferred polymerizable groups (P) are vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxy groups, most preferably acrylate or methacrylate, in particular acrylate.

[0076] Preferably, all polyreactive polymerizable compounds and subformulae thereof contain, instead of one or more groups P-Sp, one or more branched groups containing two or more polymerizable groups P (polyreactive polymerizable groups).

[0077] Suitable groups of this type and polymerizable compounds containing them are described, for example, in US Pat. No. 7,060,200 B1 or US 2006 / 0172090 A1.

[0078] Particularly preferred are multi-reactive polymerizable groups selected from the following formulae:

[0079] -X-alkyl-CHP x -CH 2 -CH 2 P y I*a

[0080] -X-alkyl-C(CH 2 P x )(CH 2 P y )-CH 2 P z I*b

[0081] -X-alkyl-CHP x CHPy -CH 2 P z I*c

[0082] -X-alkyl-C(CH 2 P x )(CH 2 P y )-C aa H 2aa+1 I*d

[0083] -X-alkyl-CHP x -CH 2 P y I*e

[0084] -X-alkyl-CHP x P y I*f

[0085] -X-alkyl-CP x P y -C aa H 2aa+1 I*g

[0086] -X-alkyl-C(CH 2 P v )(CH 2 P w )-CH 2 OCH 2 -C(CH 2 P x )(CH 2 Py)CH 2 P z I*h

[0087] -X-alkyl-CH((CH 2 ) aa P x )((CH 2 ) bb P y ) I*i

[0088] -X-alkyl-CHP x CHP y -C aa H 2aa+1 I*k

[0089] in

[0090] Alkyl represents a single bond or a straight-chain or branched alkylene group having 1 to 12 C atoms, wherein one or more non-adjacent CH 2 The groups may each be independently replaced by -C(Rx )=C(R x )-、-C≡C-、-N(R x )-, -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O- in such a way that O and / or S are not directly connected to each other, and wherein in addition, one or more H atoms may be replaced by F, Cl or CN, wherein R x has any of the meanings set out above,

[0091] aa and bb each independently represents 0, 1, 2, 3, 4, 5 or 6,

[0092] X has one of the meanings indicated for X', and

[0093] P v To P z each independently of the others has one of the meanings indicated above for P.

[0094] Preferred spacer groups Sp are selected from the formula Sp'-X', such that the group "P-Sp-" conforms to the formula "P-Sp'-X'-", wherein

[0095] Sp' denotes alkylene having 1 to 20, preferably 1 to 12 C atoms, which is optionally mono- or polysubstituted by F, Cl, Br, I or CN, wherein in addition one or more non-adjacent CH 2 The groups can be independently replaced by -O-, -S-, -NH-, -NR xx -、-SiR xx R yy -, -CO-, -COO-, -OCO-, -OCO-O-, -S-CO-, -CO-S-, -NR xx -CO-O-, -O-CO-NR 0xx -、-NR xx -CO-NR yy -, -CH=CH- or -C≡C- are substituted in such a way that O and / or S are not directly connected to each other,

[0096] X' represents -O-, -S-, -CO-, -COO-, -OCO-, -O-COO-, -CO-NR xx -、-NR xx -CO-、-NR xx -CO-NR yy -、-OCH 2 -、-CH 2 O-、-SCH 2 -、-CH 2 S-、-CF2 O-、-OCF 2 -、-CF 2 S-, -SCF 2 -、-CF 2 CH 2 -、-CH 2 CF 2 -、-CF 2 CF 2 -, -CH=N-, -N=CH-, -N=N-, -CH=CR xx -、-CY xx =CY xx -, -C≡C-, -CH=CH-COO-, -OCO-CH=CH- or a single bond,

[0097] R xx and R yy each independently of one another represents H or an alkyl group having 1 to 12 C atoms, and

[0098] Y xx and Y yy each independently represents H, F, Cl or CN,

[0099] X' is preferably -O-, -S--CO-, -COO-, -OCO-, -O-COO-, -CO-NR xx -、-NR xx -CO-、-NR xx -CO-NR yy - or single key.

[0100] A typical spacer group Sp' is, 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 -,

[0101] wherein p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R xx and R yy Has the meanings stated above.

[0102] A particularly preferred group -X'-Sp'- is -(CH 2 ) p1 -、-O-(CH 2 ) p1 -、-OCO-(CH 2 ) p1 -、-OCOO-(CH 2 ) p1 -, wherein p1 is an integer from 1 to 12.

[0103] Particularly preferred radicals 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, vinylene, propenylene and butenylene.

[0104] Preferred group A 1 and A 2 Including but not limited to: furan, pyrrole, thiophene, oxazole, thiazole, thiadiazole, imidazole, phenylene, cyclohexylene, bicyclooctylene, cyclohexenylene, pyridine, pyrimidine, pyrazine, azulene, indane, fluorene, naphthalene, tetralin, anthracene, phenanthrene and dithienothiophene, all of which are unsubstituted or substituted by 1, 2, 3 or 4 of the above defined groups L.

[0105] Particularly preferred groups A 1 and A 2 is 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-tetrahydronaphthalene-2,6-diyl, indan-2,5-diyl, bicyclooctylene or 1,4-cyclohexylene, wherein one or two non-adjacent CH 2 The radicals are optionally replaced by O and / or S, where these radicals are unsubstituted or substituted by 1, 2, 3 or 4 radicals L as defined above.

[0106] Particularly preferred groups Z 1 In each case, independently of one another, it is preferably selected from the group consisting of -COO-, -OCO-, -CH 2 CH 2 -、-CF 2 O-、-OCF 2 -, -C≡C-, -CH=CH-, -OCO-CH=CH-, -CH=CH-COO- or a single bond.

[0107] Very preferred direactive mesogenic compounds of the formula DRM are selected from the following formulae:

[0108]

[0109]

[0110] in

[0111] P 0 in the case of multiple occurrences independently of one another is a polymerizable group, preferably an acryloyl, methacryloyl, oxetanyl, epoxide, vinyl, heptadienyl, vinyloxy, propenyl ether or styryl group,

[0112] L has the same or different L in targeted DRM at each occurrence 1 one of the meanings given above and preferably, in the case of multiple occurrences, independently of one another, is selected from F, Cl, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 5 C atoms,

[0113] r is 0, 1, 2, 3, or 4,

[0114] x and y are independently 0 or the same or different integers from 1 to 12,

[0115] Each z is independently 0 or 1, and if the adjacent x or y is 0, then z is 0.

[0116] Particularly preferred are compounds of the formulae DRMa1, DRMa2 and DRMa3, in particular the compound of the formula DRMa1.

[0117] In another preferred embodiment, the one or more polymerizable compounds used in the ink formulation according to the invention are selected from monoreactive liquid crystal compounds of the formula MRM,

[0118] P 1 -Sp 1 -MG-R MRM

[0119] Where P 1 、Sp 1 and MG have the meanings given in Formula DRM,

[0120] R represents F, Cl, Br, I, -CN, -NO 2 , -NCO, -NCS, -OCN, -SCN, -C(=O)NR x R y , -C(=O)X, -C(=O)OR x 、-C(=O)R y 、-NRx R y , -OH, -SF 5 , optionally substituted silyl, straight-chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 12 C atoms, preferably 1 to 6 C atoms, wherein one or more H atoms are optionally replaced by F or Cl,

[0121] X is halogen, preferably F or Cl, and

[0122] R x and R y are independently H or alkyl having 1 to 12 C atoms.

[0123] Preferred monoreactive mesogenic compounds of formula MRM are selected from the following formulae:

[0124]

[0125]

[0126]

[0127]

[0128] Where P 0 , L, r, x, y and z are as defined in Formula DRMa-1 to Formula DRMe,

[0129] R 0 is alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 or more, preferably 1 to 15, C atoms, or represents Y 0 ,

[0130] Y 0 It is F, Cl, CN, NO 2 、OCH 3 、OCN、SCN、SF 5 , or monofluorinated, oligofluorinated or polyfluorinated alkyl or alkoxy having 1 to 4 C atoms,

[0131] Z 0 It is -COO-, -OCO-, -CH 2 CH 2 -、-CF 2 O-、-OCF 2 -, -CH=CH-, -OCO-CH=CH-, -CH=CH-COO- or a single bond,

[0132] A 0is, in the case of multiple occurrences, independently of one another, 1,4-phenylene, which is unsubstituted or substituted by 1, 2, 3 or 4 radicals L, or trans-1,4-cyclohexylene,

[0133] u and v are independently 0, 1, or 2,

[0134] w is 0 or 1,

[0135] and wherein the benzene ring and the naphthalene ring may additionally be substituted by one or more identical or different radicals L.

[0136] Further preferred are compounds of the formulae MRM1, MRM2, MRM3, MRM4, MRM5, MRM6, MRM7, MRM9 and MRM10, especially compounds of the formulae MRM1, MRM4, MRM6 and MRM7, in particular compounds of the formulae MRM1 and MRM7.

[0137] Compounds of the formulae DRM, MRM and subformulae thereof can be prepared analogously to methods known to the person skilled in the art and described in standard texts of organic chemistry (eg Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Thieme-Verlag, Stuttgart).

[0138] The compounds of the formulae DRM, MRM and subformulae thereof can preferably be used alone or in combination with one another.

[0139] Preferably, the polymerizable liquid crystal compound used comprises a compound selected from one or more compounds of formula DRM, more preferably selected from one or more compounds of formula DRM and one or more compounds of formula MRM.

[0140] The proportion of compounds of the formulae DRM, MRM and subformulae thereof in the total amount of the polymerizable liquid-crystalline compounds used is preferably 30-99.9% by weight, more preferably 40-99.9% by weight, even more preferably 50-99.9% by weight.

[0141] In a preferred embodiment, the proportion of the direactive polymerizable mesogenic compound in the total amount of the polymerizable liquid crystal compound used is preferably 5-99% by weight, more preferably 10-97% by weight, even more preferably 15-95% by weight.

[0142] In another preferred embodiment, the proportion of the monoreactive polymerizable mesogenic compound, if present, in the total amount of the polymerizable liquid-crystalline compound used is preferably 5-80% by weight, more preferably 10-75% by weight, even more preferably 15-70% by weight.

[0143] In another preferred embodiment, the proportion of the polyreactive polymerizable mesogenic compound, if present, in the overall polymerizable liquid-crystalline material according to the invention is preferably 1 to 30% by weight, more preferably 2 to 20% by weight, even more preferably 3 to 10% by weight.

[0144] In another preferred embodiment, the polymerisable LC material does not comprise a polymerisable mesogenic compound having more than two polymerisable groups.

[0145] In another preferred embodiment, the polymerisable LC material does not comprise polymerisable mesogenic compounds having less than two polymerisable groups.

[0146] Preferably, the one or more organic solvents, preferably all selected solvents are selected from solvents having a boiling point in the range of 60 to 380°C, preferably in the range of 100 to 340°C, most preferably in the range of 120 to 330°C.

[0147] Preferably, the organic solvent(s), preferably all selected solvents are selected from solvents having a melting point preferably below 25°C, which means that the selected solvents are liquid at room temperature.

[0148] Preferably, the one or more organic solvents, preferably all selected solvents are selected from solvents having a viscosity > 15 mPas, preferably > 20 mPas, more preferably > 25 mPas, most preferably > 50 mPas.

[0149] Preferably, one or more organic solvents, preferably all selected solvents, are selected from solvents in which the polymerizable liquid-crystalline compound used exhibits solubility in the selected solvent at ≥ 5 g / l, preferably ≥ 10 g / l.

[0150] Examples of preferred organic solvents and their boiling points (BP) and melting points (MP) are shown in Table 1 below.

[0151] Table 1: Preferred solvents and their boiling points (BP) and melting points (MP).

[0152]

[0153] The preferred organic solvent system or mixture is the following combination: cyclohexanone: di(propylene glycol) methyl ether acetate, cyclohexanone: propylene glycol monomethyl ether acetate, or di(propylene glycol) methyl ether acetate: propylene glycol monomethyl ether acetate. The preferred mixing ratio of the organic solvent system is between 2:1 and 1:2.

[0154] The viscosity of the formulations of the present invention is preferably from 0.8 to 50 mPa.s, more preferably from 1 to 40 mPa.s, most preferably from 2 to 15 mPa.s.

[0155] The viscosity of the formulations and solvents according to the invention was measured using a 1° cone-plate rotational rheometer model Discovery AR3 (Thermo Scientific). This instrument allows precise control of temperature and shear rate. The viscosity was measured at a temperature of 25.0°C (+ / -0.2°C) and a shear rate of 500 s -1 Each sample was measured three times and the measured values ​​were averaged.

[0156] The surface tension of the formulations of the present invention is preferably from 15 to 70 mN / m, more preferably from 10 to 50 mN / m, most preferably from 20 to 40 mN / m.

[0157] Preferably, the surface tension of the organic solvent blend is from 15 to 70 mN / m, more preferably from 10 to 50 mN / m, most preferably from 20 to 40 mN / m.

[0158] Surface tension can be measured using a FTA (First Ten Angstrom) 1000 contact angle goniometer at 20°C. Details of the method can be obtained from First Ten Angstrom, as disclosed in "Surface Tension Measurements Using the Drop Shape Method" by Dr. Roger P. Woodward. Preferably, the surface tension can be determined using the hanging drop method. This measurement technique dispenses a drop of liquid from a needle in a bulk liquid or gas phase. The shape of the drop is determined by the relationship between surface tension, gravity, and density differences. Using the hanging drop method, the surface tension is calculated from the shadow image of the hanging drop using http: / / www.kruss.de / services / education-theory / glossary / drop-shape-analysis. Commonly used commercially available high-precision drop shape analysis tools, namely the First Ten The FTA1000 of the company was used to perform all surface tension measurements. The surface tension was determined by the FTA1000 software. All measurements were performed at room temperature, ranging between 20°C and 25°C. The standard operating procedure involves determining the surface tension of each formulation using a new disposable droplet dispensing system (syringe and needle). The measurement duration for each droplet is one minute and the number of measurements is 60, which are then averaged. Three drops are measured for each formulation. The final value is the average of the measurements. The tool is regularly cross-checked with various liquids with known surface tensions.

[0159] For the preparation of brightness enhancement films, cholesteric polymerizable liquid crystal ink formulations are usually used.Thus, in a preferred embodiment, the polymerizable liquid crystal ink formulation according to the invention comprises one or more chiral additives, which are used to induce a cholesteric phase.

[0160] Preferred chiral additives may be selected from chiral RMs and chiral dopants, many of which are well known to the skilled person and are commercially available.

[0161] Suitable non-polymerizable chiral compounds are, for example, chiral dopants such as R- or S-811, R- or S-1011, R- or S-2011, R- or S-3011, R- or S-4011, R- or S-5011 or CB 15 (all available from Merck KGaA, Darmstadt, Germany).

[0162] Suitable polymerizable chiral compounds are, for example, the chiral RMs (R1) to (R10) listed below, or polymerizable chiral materials LC756 (from BASF AG, Ludwigshafen, Germany).

[0163]

[0164]

[0165] Where P has the above 0 One of the meanings given, Z 0 ,u,v,x,y,R 0 and A are as defined above, and L 1 and L 2 independently of one another have one of the meanings of L given above.

[0166] Very preferred are chiral compounds with a high HTP, in particular compounds containing a sorbitol group, for example as described in WO 98 / 00428, compounds containing a hydrobenzoin group, for example as described in GB 2,328,207, chiral binaphthol derivatives, for example as described in WO 02 / 94805, chiral binaphthol acetal derivatives, for example as described in WO 02 / 34739, chiral TADDOL derivatives, for example as described in WO 02 / 06265, and chiral compounds having at least one fluorinated linker and a terminal or central chiral group, for example as described in WO 02 / 06196 or WO 02 / 06195.

[0167] It is particularly preferred that the HTP is 40 μm -1 or higher, very preferably 60 μm -1 or higher, most preferably 80 μm -1 or higher chiral compounds.

[0168] Particularly preferred are polymerizable sorbitols, such as those of formula (R8) and (R9), and polymerizable hydrogenated benzoins, such as those of formula (R10).

[0169] Further preferred are non-polymerizable sorbitol and hydrogenated benzoin of the following formulae M1 and M2.

[0170] Further preferred are chiral binaphthols of the following formulae M3 and M4.

[0171]

[0172] Among them, P, Z 0 , AL 1 , L 2 , v and x have the meanings given above, R 1 With the R given above 0 One of the meanings is P-Sp, R has R 0 , m is 0, 1, 2 or 3, and r1 and r2 are 0, 1, 2, 3 or 4.

[0173] Very preferred are compounds of formula M3, wherein R 1 is P-Sp. Further preferred are compounds of formula M3, wherein m is 0 or 1, Z 0 is -COO-, -OCO- or a single bond, A is optionally replaced by 1 or 2 groups L 1 Substituted 1,4-phenylene, or trans-1,4-cyclohexylene.

[0174] The formulation containing the chiral additive preferably exhibits a cholesteric LC phase, very preferably a cholesteric LC phase at room temperature.

[0175] In another preferred embodiment, the formulation optionally comprises one or more additives selected from other polymerization initiators, antioxidants, surfactants, stabilizers, catalysts, sensitizers, inhibitors, chain transfer agents, co-reacted monomers, reactive diluents, surface-active compounds, lubricants, wetting agents, dispersants, hydrophobic agents, binders, flow improvers, degassing or defoaming agents, deoxidizers, diluents, reactive diluents, auxiliaries, colorants, dyes, pigments and nanoparticles.

[0176] Lubricants and flow aids usually include polymers that do not contain silicon, but also silicon-containing polymers, such as polyacrylates or modifiers, low molecular weight polydialkylsiloxanes. The modification consists in that some of the alkyl groups are replaced by various organic groups. These organic groups are, for example, polyethers, polyesters or even long-chain (fluorinated) alkyl groups, the former being the most used.

[0177] The polyether groups in the corresponding modified polysiloxanes are usually composed of ethylene oxide units and / or propylene oxide units. Generally, the higher the proportion of these alkylene oxide units in the modified polysiloxane, the stronger the hydrophilicity of the resulting product.

[0178] Such auxiliaries are available, for example, from the company Tego as Glide 100, Glide ZG 400, Glide 406, Glide 410, Glide 411, Glide 415, Glide 420, Glide 435, Glide 440, Glide 450, Glide A115, Glide B 1484 (can also be used as a defoamer and deoxidizer), Flow ATF, Flow300, Flow 460, Flow 425 and Flow ZFS 460 is commercially available. Suitable radiation curing lubricants and flow aids (which may also be used to improve scratch resistance) are product Rad 2100, Rad2200, Rad 2500, Rad 2600 and Rad 2700, these products are also available from TEGO.

[0179] Such additives are also available from BYK as -300 -306, -307, -310, -320, -333, -341, 354, 361, 361N, 388 obtained.

[0180] Such additives can also be obtained, for example, from 3M get.

[0181] Such adjuvants are also available, for example, from Cytonix as 561 or 562 obtained.

[0182] Such auxiliaries are also available, for example, from Merck KGaA and FL 2300 and FL 2500 obtained.

[0183] These adjuvants are optionally used in a proportion of about 0 to 3.0% by weight, preferably about 0 to 2.0% by weight, relative to all solids or components (excluding the solvent or solvents present).

[0184] In another preferred embodiment, the formulation comprises one or more specific antioxidant additives, preferably selected from series, such as antioxidants commercially available from Ciba, Switzerland 1076 and 1010.

[0185] In another preferred embodiment, the formulation comprises one or more photoinitiators, for example, selected from commercially available or (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).

[0186] The overall concentration of the one or more polymerization initiators in the formulation is preferably 0.5-10% by weight, very preferably 0.8-8% by weight, more preferably 1-6% by weight, relative to all solids or components (excluding the one or more solvents present).

[0187] Preferably, the ink formulation comprises, in addition to one or more di- or poly-reactive polymerizable mesogenic compounds and one or more solvents,

[0188] a) one or more monoreactive polymerizable mesogenic compounds,

[0189] b) one or more photoinitiators,

[0190] c) optionally one or more antioxidant additives,

[0191] d) optionally one or more stabilizers,

[0192] e) optionally one or more lubricants and flow aids.

[0193] More preferably, the formulation comprises, in addition to one or more, preferably two or more, direactive polymerizable mesogenic compounds (if present, preferably in an amount of 10 to 90% by weight, very preferably 15 to 75% by weight, relative to all components without the solvent(s), preferably selected from compounds of formula DRMa-1) and one or more solvents,

[0194] a) optionally one or more, preferably two or more, monoreactive polymerizable mesogenic compounds, preferably in an amount of 10 to 95% by weight, very preferably 25 to 85% by weight, relative to all components without the solvent(s), preferably selected from compounds of the formula MRM-1 and / or MRM-7,

[0195] b) optionally one or more, preferably one, photoinitiator, if present, in an amount preferably of 1 to 10% by weight, very preferably 2 to 7% by weight, relative to all components without the solvent(s),

[0196] c) optionally one or more antioxidant additives, preferably selected from esters of unsubstituted and substituted benzoic acids, in particular 1076, if present, is preferably present in an amount of 0.01-2% by weight, very preferably 0.05-1% by weight, relative to all components without solvent(s).

[0197] d) optionally one or more lubricants and flow aids, preferably selected from Rad2500, 388, FC 4430 and / or Fluor N 562, if present, are preferably present in an amount of 0.1 to 5% by weight, very preferably 0.2 to 3% by weight, relative to all components without the solvent(s).

[0198] Further, the present invention relates to a method for producing an ink formulation by mixing at least 10 to 50 % w / w of one or more polyreactive or direactive liquid crystal compounds, relative to the entire formulation, with 50 to 90 % w / w of one or more solvents, selected from aliphatic ketones, cyclic ketones, alkyl ethers of ethylene glycol or propylene glycol or aromatic solvents, relative to the entire formulation.

[0199] Furthermore, the present invention relates to the use of the ink formulation as described above and below in an inkjet printer. Suitable inkjet printers are known to the skilled person, for example the Materials Printer series, such as DMP-2800 or LP 50 Meyer Burger.

[0200] Further, the present invention relates to a method for producing a polymer film comprising the steps of inkjet printing an ink formulation as described above and below on a substrate and curing the ink formulation.

[0201] The area and thickness of the provided layer may vary according to different purposes. Typically, the formulation is provided with a thickness of 500 nm to 2500 nm, preferably 1000 nm to 2000 nm, more preferably 1500 nm to 1900 nm.

[0202] Typically, the area or print size provided is 1cm 2 Up to 10μm 2 , for use in color filters as described below, it is preferred that the area or print size provided corresponds to the sub-pixel size, typically 1 mm to 0.01 mm, as the minimum length of any pixel shape.

[0203] Preferably, a suitable droplet spacing is selected to be 100 μm to 10 μm, preferably 50 μm to 15 μm.

[0204] Suitable substrate materials or substrates are known to the expert and described in the literature, for example conventional substrates used in the optical film industry, such as glass or plastics. Particularly suitable and preferred polymeric substrates are polyesters, such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polyvinyl alcohol (PVA), polycarbonate (PC), triacetyl cellulose (TAC), or cycloolefin polymers (COP), or known color filter materials, in particular triacetyl cellulose (TAC), cycloolefin polymers (COP), or known color filter materials.

[0205] In a preferred embodiment, the method according to the invention comprises a method step in which the ink formulation is allowed to stand for a period of time in order to allow the ink to be evenly redistributed on the substrate (herein referred to as "annealing").

[0206] Preferably, the ink is annealed after printing for a period of 1 minute to 3 hours, preferably 2 minutes to 1 hour, most preferably 5 minutes to 30 minutes. Annealing is preferably carried out at room temperature.

[0207] In an alternative embodiment, annealing is performed at elevated temperature, preferably above 20°C and below 140°C, more preferably above 40°C and below 100°C, most preferably above 50°C and below 90°C.

[0208] The polymerisable LC material (RM or reactive mesogen) of the ink formulation preferably exhibits a uniform alignment over the entire layer after being cured or inkjet printed on the substrate. Preferably, the polymerisable LC material exhibits a uniform planar alignment or a uniform homeotropic alignment.

[0209] The Friedel-Creagh-Kmetz rule can be used to predict whether the mixture will adopt a planar or homeotropic alignment by comparing the surface energies of the RM layer and the substrate.

[0210] If γ RM >γ s , then the reactive mesogenic compound will show homeotropic alignment; if γ RM <γ s , then the reactive mesogen compound will show plane alignment.

[0211] When the surface energy of the substrate is relatively low, the intermolecular forces between the reactive mesogens are stronger than the forces across the RM-substrate interface. Therefore, the reactive mesogens are aligned perpendicular to the substrate (homeotropic alignment) to maximize the intermolecular forces.

[0212] Homeotropic alignment can also be achieved by using hydrophilic materials; they can be added directly to the polymerizable 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, while the hydrocarbon tail is perpendicular to the substrate. The intermolecular interactions between the amphiphilic material and the RM promote homeotropic alignment. Commonly used amphiphilic surfactants are described above.

[0213] Another method for promoting homeotropic alignment is to subject the plastic substrate to corona discharge treatment to generate alcohol or ketone functional groups on the substrate surface. These polar groups can interact with the polar groups present in RM or surfactant to promote homeotropic alignment.

[0214] When the surface tension of the substrate is greater than that of the RM, the forces across the interface dominate. If the reactive mesogens are aligned parallel to the substrate, the interfacial energy is minimized, so the long axis of the RM can interact with the substrate. One way to promote along-plane alignment is to coat the substrate with a polyimide layer and then rub the alignment layer with a flannel.

[0215] Other suitable surface alignment layers are known in the art, such as rubbed polyimides described in US 5,602,661, US 5,389,698 or US 6,717,644 or alignment layers prepared by photoalignment.

[0216] In general, reviews of alignment techniques are given, for example, by I. Sage, "Thermotropic Liquid Crystals", GW Gray, ed., John Wiley & Sons, 1987, pp. 75-77; and T. Uchida and H. Seki, "Liquid Crystals - Applications and Uses Vol. 3", B. Bahadur, ed., World Scientific Publishing, Singapore 1992, pp. 1-63. Other reviews of alignment materials and techniques are given by J. Cognard, Mol. Cryst. Liq. Crystal. 78, Supplement 1 (1981), pp. 1-77.

[0217] To produce the polymer membrane according to the invention, the polymerizable compounds in the formulation are cured, polymerized or crosslinked (if one compound contains two or more polymerizable groups).

[0218] In a preferred method of preparation, the formulation is printed onto a substrate and then photopolymerized by exposure to actinic radiation, for example as described in WO 01 / 20394, GB 2,315,072 or WO 98 / 04651.

[0219] The photopolymerization of the formulation is preferably achieved by exposing it to actinic radiation. Actinic radiation refers to irradiation with light, such as 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. Preferably, the polymerization is carried out by irradiation with light, in particular with UV light. As a source of actinic radiation, for example, a single UV lamp or a group of UV lamps can be used. When using high lamp powers, the curing time can be reduced. Another possible source of actinic radiation is a laser, for example a UV laser, an IR laser or a visible laser.

[0220] The curing time depends mainly on the reactivity of the polymerizable LC compound, the thickness of the printed layer, the type of polymerization initiator and the power of the UV lamp.

[0221] Typically, the curing time is preferably ≤ 5 minutes, very preferably ≤ 3 minutes, most preferably ≤ 1 minute. For large-scale production, a short curing time of ≤ 30 seconds is preferred.

[0222] Suitable UV radiation power is preferably 5 to 200 mWcm -2 , more preferably 50 to 175 mWcm -2 , most preferably 100 to 150 mWcm -2 .

[0223] Depending on the UV radiation applied and as a function of time, a suitable UV dose is preferably 25 to 7200 mJcm -2 , more preferably 500 to 7200 mJcm -2 , most preferably 3000 to 7200 mJcm -2 .

[0224] The photopolymerization is preferably carried out in an inert gas environment, preferably a heated nitrogen environment, but the polymerization can also be carried out in air.

[0225] The photopolymerization is preferably carried out at a temperature of 1 to 70°C, more preferably 5 to 50°C, even more preferably 15 to 30°C.

[0226] The polymerized LC film according to the present invention has good adhesion to plastic substrates, in particular to TAC, COP and color filters. It can therefore serve as an adhesive or base coating for subsequent LC layers that would otherwise not adhere well to the substrate.

[0227] For example, the uniform homeotropic or planar aligned polymer films of the present invention can be used as retardation or compensating or reflective films, for example in LCDs, to improve contrast and brightness at large viewing angles and to reduce chromaticity. They can be used outside the switchable liquid crystal cell in an LCD, or between the substrate (usually a glass substrate) forming the switchable liquid crystal cell and containing the switchable liquid crystal medium (in a cell application).

[0228] The present invention therefore also relates to the use of a polymer film as described above and below as an optical film or in an optical component.

[0229] The optical retardation (δ(λ)) of a polymer film as a function of the wavelength (λ) of the incident beam is given by:

[0230] δ(λ)=(2πΔn·d) / λ

[0231] where (Δn) is the birefringence of the film, (d) is the thickness of the film, and λ is the wavelength of the incident light.

[0232] According to Snellius's law, the birefringence as a function of the incident beam direction is defined as

[0233] Δn=sinΘ / sinΨ

[0234] where sinΘ is the angle of incidence or the tilt angle of the optical axis in the film and sinΨ is the corresponding reflection angle.

[0235] Based on these laws, the birefringence and the corresponding optical retardation depend on the thickness of the film and the tilt angle of the optical axis in the film (cf. Berek's compensator). Thus, the skilled expert knows that different optical retardation or different birefringence can be induced by adjusting the thickness of the ink formulation or the polymer film.

[0236] The birefringence (Δn) of the polymer film according to the present invention is preferably from 0.01 to 0.30, more preferably from 0.01 to 0.25, even more preferably from 0.01 to 0.16.

[0237] The polymer film according to the invention has an optical retardation as a function of thickness of less than 200 nm, more preferably less than 180 nm, even more preferably less than 160 nm.

[0238] The polymer films of the invention can also be used as alignment films for other liquid crystal or RM materials. For example, they can be used in LCDs to induce or improve the alignment of a switchable liquid crystal medium, or to align a layer of polymerizable LC material subsequently coated thereon. In this way, stacks of polymerized LC films can be prepared.

[0239] In summary, the polymer film according to the present invention can be used in optical components such as polarizers, compensators, alignment layers, circular polarizers or color filters in liquid crystal displays or projection systems, especially in reflective films with spatially varying reflection colors.

[0240] Therefore, the present invention also relates to an optical component comprising one or more polymer films obtainable or obtained from an ink formulation as described above and below.

[0241] In another preferred embodiment, the optical component comprises one or more, preferably two or more polymer films obtainable or obtained from the ink formulation as described above and below, selected from A-plate, C-plate, biaxial polymer film, or cholesteric polymer film, or even any combination thereof.

[0242] Preferably, the present invention relates to a color filter comprising one or more, preferably two or more, polymer films obtainable or obtained from an ink formulation as described above and below.

[0243] Preferably, the color filter includes a plurality of color pixel patterns having certain delays, and the polymer film on the plurality of color pixel patterns can be obtained by an ink formulation provided by inkjet printing corresponding to each delay of the plurality of color pixel patterns, wherein the liquid crystal phase-shift layer includes a plurality of liquid crystal phase-shift regions corresponding to the plurality of color patterns; the plurality of liquid crystal phase-shift regions have delays that correct the delays of the plurality of color pixel patterns; and the sum of the delays of the plurality of color pixel patterns and the delays of the corresponding plurality of polymer film phase-shift regions is characteristic and substantially the same for each pixel.

[0244] For this purpose, it is preferred that the color filter comprises one or more, preferably two or more, polymer films obtainable or obtained from the ink formulation as described above and below, having a different birefringence for each sub-pixel of the color filter, such as red, green and blue.

[0245] More preferably, the present invention relates to a color filter based on quantum materials comprising one or more, preferably two or more, polymer films obtainable or obtained from an ink formulation as described above and below.

[0246] For this purpose, it is preferred that the color filter comprises one or more, preferably two or more, cholesteric polymer films obtainable or obtained from the ink formulations as described above and below, having different reflective properties for each sub-pixel of the color filter, such as red, green and blue. For example, a red / green / blue CLC reflector having both left-handed and right-handed spiral orientations for each sub-pixel of the color filter.

[0247] The polymer films according to the invention can be used for transmissive or reflective displays. They can be used for conventional or QD-type OLED and LCD displays, which contain pixel color conversion modules (PCCs), in particular LCDs in DAP (deformation of alignment phase) or VA (vertical alignment) mode, such as ECB (electrically controlled birefringence), CSH (color super vertical plane), VAN or VAC (vertically aligned nematic or cholesteric) displays, MVA (multi-domain vertical alignment) or PVA (patterned vertical alignment) displays, curved mode displays or hybrid displays, such as OCB (optically compensated bending box or optically compensated birefringence), R-OCB (reflective OCB), HAN (hybrid alignment nematic) or pi-box (π-box) displays, in addition to TN (twisted nematic), HTN (highly twisted nematic) or STN (super twisted nematic) mode displays, AMD-TN (active matrix driven TN) displays, or IPS (in-plane switching) mode displays, also known as "super TFT" displays. Particularly preferred are VA, MVA, PVA, OCB and pi-box displays.

[0248] Therefore, another aspect of the present invention is the use of one or more polymer films as described above and below or optical components in an optical device or an optical device comprising one or more optical components, wherein the optical component comprises one or more polymer films obtainable or obtained from one or more ink formulations as described above and below.

[0249] Many of the compounds mentioned above and below or mixtures thereof are commercially available on the market. All of these compounds are known or can be prepared by methods known per se, as described in the literature (for example in standard works such as Houben-Weyl, Methoden der Organischen Chemie [Methods of Organic Chemistry], Georg-Thieme-Verlag, Stuttgart), precisely under reaction conditions known and suitable for the reactions described. Variants known per se but not mentioned here can also be used here.

[0250] It is understood that the above embodiments of the present invention may be modified while still falling within the scope of the present invention. Unless otherwise specified, alternative features serving the same, equivalent or similar purpose may replace each feature disclosed in this specification. Therefore, unless otherwise specified, each feature disclosed is only an example in a series of equivalent or similar features.

[0251] All features disclosed in this specification may be combined in any manner, except that at least some of such features and / or steps are mutually exclusive combinations. In particular, preferred features of the present invention are applicable to all aspects of the present invention and may be used in combination in any manner. Similarly, features described in non-essential combinations may be used alone (not in combination).

[0252] It is to be understood that many of the features described above, especially the features of the preferred embodiments, are inventive in their own right, and not just as part of the embodiments of the present invention. Independent protection may be sought for these features to supplement or replace any invention currently claimed.

[0253] The present invention will now be described in more detail with reference to the following working examples, which are illustrative only and are not intended to limit the scope of the present invention. DETAILED DESCRIPTION

[0254] Working Example

[0255] Reactive mesogen mixture (RMM) used:

[0256] The following reactive mesogen mixtures were prepared according to the table below:

[0257] RMM 1:

[0258]

[0259] RMM 2:

[0260]

[0261]

[0262] RMM 3:

[0263]

[0264] Solvents and solvent systems used

[0265]

[0266] Inkjet printer used:

[0267] 1Fujifilm Materials Printer 2800

[0268] 2. Meyer Burger LP 50.

[0269] General process:

[0270] The ink formulations were prepared by mixing the corresponding RMM and the corresponding solvent system (SS). The inks were then printed at a given drop spacing (DS) in a given print size (PD). The layers were then annealed at 90°C for 60 seconds and cooled to room temperature. The layers were then cured in air with an Omnicure lamp at 250-450 nm at 50 mW for 120 seconds. After curing, the birefringence (Δn) and, in the case of cholesteric polymer films, the central reflection wavelength (λ) and the reflection bandwidth (dλ) were determined.

[0271] Working Example:

[0272] Non-cholesteric polymer membranes:

[0273]

[0274]

[0275] Cholesteric polymer membrane:

[0276]

Claims

1. An ink formulation for inkjet printing comprising 10 to 50% w / w of one or more polymerizable liquid crystal compounds and 50 to 90% w / w of one or more organic solvents, The polymerizable liquid crystal compound is selected from: one or more di- or poly-reactive compounds of formula DRMa1, In the above formula, the group P 0 is an acrylate group or a methacrylate group; L is selected, independently of one another in the case of multiple occurrences, from F, Cl, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 5 C atoms, r is 0, 1, 2, 3, or 4, x and y are independently 0 or the same or different integers from 1 to 12, z is each independently 0 or 1, and z is 0 if the adjacent x or y is 0; and One or more compounds selected from the group consisting of formula MRM1, MRM4, MRM6 and MRM7: Where P 0 , L, r, x, y and z are as defined in formula DRMa-1, R 0 is an alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy radical having 1 to 15 C atoms, or represents Y 0 , Y 0 It is F, Cl, CN, NO 2 、OCH 3 、OCN、SCN、SF 5 , or monofluorinated, oligofluorinated or polyfluorinated alkyl or alkoxy having 1 to 4 C atoms, wherein the benzene ring and the naphthalene ring may additionally be substituted by one or more identical or different groups L, u and v are independently 0, 1, or 2, w is 0 or 1, and The organic solvent is a combination of: cyclohexanone: di(propylene glycol) methyl ether acetate; cyclohexanone: propylene glycol monomethyl ether acetate; or di(propylene glycol) methyl ether acetate: propylene glycol monomethyl ether acetate; the mixing ratio of the organic solvent system is in the range of 2:1 to 1:

2.

2. The ink formulation according to claim 1, comprising one or more chiral additives.

3. The ink formulation according to claim 1 or 2, comprising one or more photoinitiators.

4. A method for producing an ink formulation by mixing at least 10 to 50% w / w of one or more polymerizable liquid crystal compounds with 50 to 90% w / w of one or more solvents, The polymerizable liquid crystal compound is selected from: one or more di- or poly-reactive compounds of formula DRMa1, In the above formula, the group P 0 is an acrylate group or a methacrylate group; L is selected, independently of one another in the case of multiple occurrences, from F, Cl, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having 1 to 5 C atoms, r is 0, 1, 2, 3, or 4, x and y are independently 0 or the same or different integers from 1 to 12, z is each independently 0 or 1, and if the adjacent x or y is 0, then z is 0; and One or more compounds selected from the group consisting of formula MRM1, MRM4, MRM6 and MRM7: Where P 0 , L, r, x, y and z are as defined in formula DRMa-1, R 0 is an alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy radical having 1 to 15 C atoms, or represents Y 0 , Y 0 It is F, Cl, CN, NO 2 、OCH 3 、OCN、SCN、SF 5 , or monofluorinated, oligofluorinated or polyfluorinated alkyl or alkoxy having 1 to 4 C atoms, wherein the benzene ring and the naphthalene ring may additionally be substituted by one or more identical or different groups L, u and v are independently 0, 1, or 2, w is 0 or 1, and The organic solvent is a combination of: cyclohexanone: di(propylene glycol) methyl ether acetate; cyclohexanone: propylene glycol monomethyl ether acetate; or di(propylene glycol) methyl ether acetate: propylene glycol monomethyl ether acetate; the mixing ratio of the organic solvent system is in the range of 2:1 to 1:

2.

5. Use of the ink formulation according to one or more of claims 1 to 3 in inkjet printers.

6. Polymer film obtainable or obtained by inkjet printing an ink formulation according to one or more of claims 1 to 3 on a substrate and curing the ink formulation.

7. Process for the production of a polymer film, comprising the steps of inkjet printing an ink formulation according to one or more of claims 1 to 3 on a substrate and curing the ink formulation.

8. Use of the polymer film according to claim 6 as an optical film or in an optical component.

9. Optical component comprising one or more polymer films according to claim 6.

10. The optical component according to claim 9, wherein the optical component comprises one or more polymer films according to claim 6 selected from A-plate, C-plate, biaxial polymer film or cholesteric polymer film or any combination thereof.

11. The optical component according to claim 9 or 10, It is characterized in that The optical component is a color filter comprising one or more polymer films according to claim 6.

12. An optical component according to one or more of claims 9 to 11, It is characterized in that The optical component is a quantum material based color filter comprising one or more polymer films according to claim 6.

13. Use of an optical component according to one or more of claims 9 to 12 in an optical device.

14. Optical device comprising one or more optical components according to claim 9, said optical components comprising one or more polymer films according to claim 6.

Images