CN111712556B

CN111712556B - Liquid-crystalline medium

Info

Publication number: CN111712556B
Application number: CN201980011690.1A
Authority: CN
Inventors: N·格雷因特; M·布雷米尔; P·苏瑟; A·L·哈里茨赫克; R·西格
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2018-02-06
Filing date: 2019-02-04
Publication date: 2023-10-24
Anticipated expiration: 2039-02-04
Also published as: TW201936907A; EP3749733A1; CN111712556A; WO2019154740A1

Abstract

The present invention relates to Liquid Crystal (LC) media comprising a polymerisable compound, to a process for their preparation, to their use for optical, electro-optical and electronic purposes, in particular in LC displays, and to LC displays comprising them.

Description

Liquid-crystalline medium

The present invention relates to Liquid Crystal (LC) media comprising a polymerisable compound, to a process for their preparation, to their use for optical, electro-optical and electronic purposes, in particular in flexible LC displays, and to LC displays comprising them.

Background

Free-form LC displays and flexible LC displays have recently attracted a great deal of attention, combining the advantages of variable shape and robustness (robustness).

The free-form LC display may have a fixed shape instead of the planar shape of a rigid flat panel display, e.g. a curved shape, or may even have a variable shape. The first type of simplest form is a curved TV, which has just been developed soon and provides an enhanced viewing experience for the viewer. Thus, it is possible to provide a display that is not only shaped in one dimension but also in two dimensions, and that can be used as, for example, a vehicle dashboard or an advertising screen.

Another type of free form display, a flexible display, has also been developed and has been proposed for use in, for example, mobile phones or smart watches, taking advantage of the flexibility. Other potential applications are foldable or rollable mobile phones, and very large screens for display or home entertainment, which due to their size need to be rollable or foldable for transport or loading. Advantageously, such devices are based on plastic substrates, rather than rigid glass substrates as used in conventional inflexible LC displays.

Another display concept, "non-fragile" display is also based on a plastic substrate and refers to a display design featuring specific robustness, durability, and resistance to mechanical shock. The use of flexible plastic substrates instead of glass substrates may reduce the risk of damage, especially for hand-held, high value devices such as mobile phones, for example, when dropped accidentally or otherwise damaged during normal use.

One of the main technical challenges of LC displays with curved or flexible substrates is that a constant LC layer thickness (also called "LC cell gap" or simply "cell gap") is crucial for proper device operation. In LC displays, defining an appropriate combination of LC layer thickness and LC material properties generally ensures that the pixel can be switched between a black state and a light transmissive state. In the case of varying layer thicknesses, undesirable disturbances in the gap distance between the substrates can create visible optical defects. It should thus be ensured that the LC layer thickness does not change due to bending or lack of rigidity of the flexible plastic substrate.

Another advantage of the flexible plastic substrate is that it can provide a lower thickness than the glass substrate, thereby enabling the fabrication of thinner LC displays. However, due to its high flexibility, it is necessary to ensure a constant cell gap for the reasons described above.

In conventional LC displays with rigid glass substrates, spacer particles are typically added to the LC layer to define and maintain a constant LC layer thickness. A possible solution for free form displays is to adapt this concept by incorporating a support structure, such as for example a polymer wall, which can both resist compression and bond the two substrates together. A suitable manufacturing method may be to pre-manufacture the polymer wall structure, spread the LC mixture on the substrate, and subsequently close the panel with a top substrate. However, a potential problem with this approach is, for example, that the support structure prevents spreading of the LC mixture and the bonding to the top substrate may be insufficient.

There is thus a strong need for free-form or nonfriable LC displays based on flexible substrates (e.g. plastic substrates) and having a constant cell gap even when deviating from a flat shape.

An alternative solution for manufacturing free-form displays with constant LC layer thickness is to create the polymer wall structure by means of a patterned photopolymerization method after the display has been assembled.

This is schematically illustrated in fig. 1a-c, which shows a polymer wall forming method. Fig. 1a shows an LC mixture consisting of LC host molecules (rods), polymerizable monomers (dots) and photoinitiators (not shown). As shown in fig. 1b, the LC mixture is filled into the display, or the LC mixture is spread on the first substrate and the second substrate is applied on top thereof, and UV radiation (indicated by arrows) is applied through the photomask. The growing polymer separates from the LC medium and thereby forms polymer walls in the irradiated areas of the mask pattern shape, as shown in fig. 1c, while the LC phase of the LC host molecules (rods) in the pixel area is restored.

The polymer wall technology as set forth above thus enables the fabrication of free-form robust displays by using specific polymerizable LC compositions. In addition, it enables the fabrication of flexible LC displays that combine the advantages of low thickness and robustness.

The formation of polymer walls by this method for LC display applications has been described in the prior art and has been suggested for use in various display modes. Also in the prior art LC mixtures have been developed to realize LC displays with flexible substrates. These LC mixtures contain reactive polymer precursors that allow the formation of polymer walls in a display by a patterned photopolymerization process as set forth above.

For example, US6130738 and EP2818534A1 disclose LC displays comprising polymer walls formed of one or two polymerizable monomers contained in the LC host mixture.

However, the LC mixtures and monomers currently used for flexible LC displays with polymer wall formation have a number of disadvantages and can still be further improved.

For example, it was observed that the polymerizable compounds and LC media used in the prior art do generally show insufficient phase separation between the polymer walls and the LC molecules of the LC host mixture. This results in undesired inclusion of LC molecules in the polymer wall on the one hand and in an increased amount of polymer molecules dissolved or dispersed in the LC host mixture on the other hand, both of which can have a negative impact on the display performance.

Thus, LC molecules trapped in the polymer walls may cause a decrease in transparency and contrast of the display, a deterioration in photoelectric response due to formation of domains having different switching speeds, and a decrease in adhesion of the polymer walls to the substrate. On the other hand, undesired amounts of polymer molecules in the LC host mixture may negatively affect the LC mixture properties.

Furthermore, it is observed that the thickness of the polymer wall is generally not constant, but variable, which can lead to pixel size non-uniformity. Furthermore, the polymer walls do not generally show sufficient stability against mechanical pressure on the one hand and sufficient elasticity on the other hand. Also, the polymer walls are typically too thick, which reduces the transparency and contrast of the display.

Another problem observed with the materials used hitherto is that they do not always meet the requirements for good phase separation, thereby leading to increased polymerization times and high crosslinking levels, and thus poor wall stability, especially under mechanical stress.

It would therefore be desirable to have improved LC mixtures and monomers for flexible LC displays that can overcome the disadvantages of the materials used in the prior art as described above.

The invention is based on the following objects: novel suitable materials for use in flexible LC displays with polymer walls, in particular LC host mixtures comprising polymerisable monomers, are provided which do not have the disadvantages indicated above or only have them to a reduced extent.

Specifically, the present invention is based on the following objectives: LC media comprising polymerizable monomers are provided which enable the formation of polymer walls in a time-efficient and cost-effective manner and which are suitable for mass production. The polymer walls formed should exhibit a well-defined phase separation from the LC host mixture, with no or a reduced amount of LC molecules defective or trapped in the polymer walls, and no or a reduced amount of polymer molecules dissolved in the LC host mixture. The polymer wall should also exhibit a constant thickness, high elasticity, high stability against mechanical or thermal stresses and good adhesion to the substrate.

It is another object of the present invention to provide improved LC host mixtures for flexible displays that should exhibit high specific resistance values, high VHR values, high reliability, low threshold voltages, short response times, high birefringence, exhibit good UV absorption, especially at longer wavelengths, allow for rapid and complete polymerization of the monomers contained therein, and reduce or prevent the occurrence of image sticking in the display.

It is a further object of the invention to provide an LC display with polymer walls that shows high transparency, good contrast, high switching speed and a large operating temperature range in the addressed state.

It is another object of the present invention to provide an improved technical solution that enables LCD technology based on flexible substrates, preferably flexible plastic substrates, with a constant cell gap, low thickness and high stability, free form, thinner and less fragile LC displays.

It is another object of the present invention to provide a polymerizable LC medium for manufacturing LC displays with polymer walls enabling simultaneously good phase separation and a high degree of cross-linking.

The above objects have been achieved according to the present invention by the materials and methods as set forth and claimed hereinafter.

It has thus surprisingly been found that at least some of the above mentioned objects can be achieved by using an LC medium comprising one or more monomers capable of polymerization by free radical polymerization and further comprising RAFT (reversible addition-fragmentation chain transfer) reagents.

The inventors of the present invention have now surprisingly found that by polymerizing monomers in LC medium in the presence of RAFT agent using RAFT polymerization, polymer walls can be formed which enable good phase separation and a high degree of cross-linking and which exhibit a constant thickness, high elasticity, high stability against mechanical pressure and good substrate adhesion.

It has also surprisingly been found that the polymerizable system of the present invention can also be used to form spacers to maintain a constant cell gap between the substrates of an LC display. This may support or even replace the spacer materials commonly used in the art.

RAFT polymerization and RAFT reagents are known in the art for the synthesis of polymers with controlled molecular weight and chain length and low polydispersity. However, its use in forming the polymer walls of flexible LC displays has not been disclosed or suggested so far.

Summary of The Invention

The present invention relates to a Liquid Crystal (LC) medium comprising a polymerizable component a and a liquid crystal component B (hereinafter also referred to as "LC host mixture"), wherein component B comprises and preferably consists of one or more mesogenic or liquid crystal compounds, and component a comprises

One or more polymerizable compounds comprising a linear or branched hydrocarbon group having 1 to 30C atoms or a monocyclic hydrocarbon group having 3 to 24 ring atoms or a bicyclic or polycyclic hydrocarbon group having 4 to 30 ring atoms and one or more free-radically polymerizable groups attached thereto,

RAFT (reversible addition-fragmentation chain transfer) reagents,

optionally a polymerization initiator.

The liquid-crystalline component B of the LC medium of the present invention is also referred to hereinafter as "LC host mixture" and preferably contains LC compounds selected only from non-polymerizable low molecular weight compounds and optionally further additives such as stabilizers or chiral dopants.

The invention further relates to an LC medium or LC display as set forth above and below, wherein the polymerizable compound or the compound of component a is polymerized by RAFT polymerization.

The invention further relates to a method of forming a polymer wall in an LC medium as set forth above and below, comprising the step of carrying out RAFT polymerization in the LC medium on one or more polymerisable compounds or components a as set forth above and below.

The invention further relates to a method of manufacturing an LC display comprising a method of forming a polymer wall as set forth above and below.

The invention further relates to a method for producing an LC medium as set forth above and below, comprising the step of mixing an LC host mixture or LC component B as set forth above and below with one or more polymerisable compounds or components a as set forth above and below and optionally with further LC compounds and/or additives.

The invention further relates to the use of LC media in LC displays, preferably in flexible LC displays.

The invention further relates to an LC display comprising an LC medium as set forth above and below.

The invention further relates to an LC display comprising a polymer wall obtainable by RAFT polymerisation of one or more polymerisable compounds or polymerisable components a as set forth above and below, or comprising an LC medium as set forth above and below.

The invention further relates to an LC display comprising a spacer obtainable by RAFT polymerisation of one or more polymerisable compounds or polymerisable components a as set forth above and below, or comprising an LC medium as set forth above and below.

The LC display of the present invention is preferably a flexible LC display and is preferably a TN, OCB, IPS, FFS, positive-VA, VA or UB-FFS display.

In another preferred embodiment, the LC display of the present invention is a Polymer Stabilized Alignment (PSA) mode display, preferably a flexible LC display, and preferably a PS-TN, PS-OCB, PS-IPS, PS-FFS, PS-positive-VA, PS-VA or PS-UB-FFS display.

In another preferred embodiment, the LC display of the present invention is a self-aligned (SA) mode display, preferably a flexible LC display, and preferably a SA-VA or SA-FFS display.

The invention further relates to an LC display comprising: at least one of the two substrates is light-transmitting; an electrode provided on each substrate or two electrodes provided on only one of the substrates, and a layer of LC medium as set forth above and below between the substrates, wherein the polymerisable compounds are polymerised by free radical polymerisation between the substrates of the display.

The invention further relates to a method for manufacturing an LC display as set forth above and below, comprising the steps of filling or otherwise providing an LC medium as set forth above and below between the substrates of the display and polymerizing the polymerizable compound by free radical polymerization.

The display of the invention has two electrodes, preferably in the form of transparent layers, applied to one or both of the substrates. In some displays (e.g., in TN, OCB, or VA displays), one electrode is applied to each of the two substrates. In other displays (e.g., in IPS, FFS, or UB-FFS displays), two electrodes are applied to only one of the two substrates.

The polymerizable compound of the polymerizable component is polymerized preferably by free radical photopolymerization, very preferably by free radical UV photopolymerization, further preferably by thermal cationic polymerization.

Brief Description of Drawings

Fig. 1 schematically illustrates a polymer wall forming method in a display according to the prior art and according to the invention.

Figures 2-7 show polarized microscopic images of the test cartridges containing the polymerizable mixtures P1-P6 after polymerization.

Terms and definitions

RAFT (reversible addition-fragmentation chain transfer) polymerization is a class of living or controlled radical polymerization mediated by RAFT agents, more precisely reversible passive radical polymerization (reversible deactivation radical polymerization) (RDRP).

RAFT polymerization allows for the controlled synthesis of polymers with well defined molecular weights and degrees of polymerization and with low polydispersity or even monodispersity. The polymerization reaction is controlled by a reversible chain transfer reaction. Wherein the propagating radical chain reacts with the RAFT agent and forms an intermediate RAFT adduct radical, which radical gene RAFT agent structure is cleavable in either direction to yield the starting material or radicals and a polymeric RAFT agent. The leaving group radical then reacts with another monomer to begin another growing polymer chain. Thus, the growth opportunities are equally distributed in the growing chain. Thus, the polymer chains formed have a narrow Polydispersity (PD). The average chain length of the polymer is proportional to the concentration of RAFT agent and the monomer to polymer conversion.

Details of RAFT polymerisation processes can be found in, for example, the following Sigma-Aldrich list brochures and articles cited therein:

https://www.sigmaaldrich.com/content/dam/sigma-aldrich/docs/SAJ/ Brochure/1/controlled-radical-polymerization-guide.pdf

as set forth above in the cited brochure, page 19, "in an ideal living polymerization, all chains are initiated at the beginning of the reaction, grow at a similar rate, and survive the polymerization: without irreversible chain transfer or termination. If the initiation is relatively rapid with respect to growth, the molecular weight distribution is extremely narrow and the chain can be extended by further addition of monomers to the reaction. In free radical polymerization, all chains are not active at the same time. In RDRP (e.g. RAFT polymerization), these features are shown in the presence of reagents capable of reversibly inactivating the propagating radicals (so that most of the active chains remain in dormant form) and in reaction conditions that support rapid equilibrium between the active and dormant chains. Under these conditions, the molecular weight may increase linearly with conversion, the molecular weight distribution may be very narrow and most of the polymerization products should include dormant chains. "

RAFT polymerization may be carried out by adding RAFT reagents to a system conventionally used for free radical polymerization, including monomers commonly employed, other components such as initiators and solvents, and reaction conditions. Thus, for example, monomers having polymerizable groups such as (meth) acrylates, (meth) acrylamides, acrylonitrile, styrene or derivatives thereof, butadiene, vinyl acetate and N-vinylpyrrolidone can be used.

Typical classes of RAFT agents include thio carbonyl thio compounds such as dithioesters, di-or trithiocarbonates, di-or trithiocarbamates and xanthates.

In the foregoing and in the following, the term "free form display" will be understood to mean a display or flexible display having a fixed shape that is not a plane parallel shape, such as, for example, a curved shape. The term "flexible display" will be understood to mean a display that is bendable without breaking, such as for example a display having a flexible plastic substrate instead of a rigid glass substrate and without any other rigid layers. The term "curved display" will be understood to mean a display having top and bottom substrates that are not plane parallel but curved.

In the foregoing and hereinafter, the term "flat panel display with reduced sensitivity to touch non-uniformity" will be understood to mean a display in which irregular brightness variation defects caused by touching the front screen of the display are reduced.

In the foregoing and in the following, the term "bicyclic or polycyclic group" will be understood to mean a group consisting of two or more fused rings, i.e. rings sharing at least one common atom (as opposed to rings linked via covalent bonds between atoms belonging to different rings), wherein the ring fusion takes place a) a sequence spanning the atoms (bridgehead), as for example in bicyclo [2.2.1] heptane (norbornane) or tricyclo [3.3.3.1] decane (adamantane), hereinafter also referred to as "bridged bicyclic or polycyclic group",

b) Across the bond between two atoms, as in bicyclo [4.4.0] decane (decalin), for example, hereinafter also referred to as "fused bicyclic or polycyclic group",

c) At a single atom (spiro atom) such as, for example, in spiro [4.5] decane, hereinafter also referred to as "spiro group".

The abbreviation "RM" is used in the above and below when referring to reactive mesogens, unless indicated otherwise.

In the above and below, a polymerizable compound or RM having one polymerizable reactive group is also referred to as "single-reactivity", a polymerizable compound or RM having two polymerizable reactive groups is also referred to as "double-reactivity", and a polymerizable compound or RM having three polymerizable reactive groups is also referred to as "triple-reactivity".

Unless otherwise indicated, the expression "LC mixture" is used in reference to LC host mixtures (i.e. without RM or polymerizable compounds), while the expression "LC medium" is used in reference to LC host mixtures plus RM or polymerizable compounds.

The polymerizable compound and RM are preferably selected from achiral compounds unless otherwise stated.

As used herein, the terms "active layer" and "switchable layer" refer to a layer comprising one or more molecules (e.g., LC molecules) having structural and optical anisotropy that change their orientation when subjected to an external stimulus, such as an electric or magnetic field, in an electro-optic display, such as an LC display, which results in a change in the transmittance of the layer for polarized or unpolarized light.

As used herein, the terms "reactive mesogen" and "RM" are understood to mean a compound comprising a mesogen or liquid crystal backbone, and one or more functional groups suitable for polymerization attached thereto, and said functional groups are also referred to as "polymerizable groups" or "P".

The term "polymerizable compound" as used herein is understood to mean a polymerizable monomer compound unless otherwise indicated.

As used herein, the term "low molecular weight compound" is understood to mean a compound that is monomeric and/or is not prepared by polymerization, as opposed to "polymeric compound" or "polymer".

As used herein, the term "non-polymerizable compound" is understood to mean a compound that does not contain functional groups suitable for polymerization under the conditions typically applied to polymerization of RM or polymerizable compounds.

As used herein, the term "mesogenic group" is known to those skilled in the art and described in the literature, and refers to a group that substantially contributes to the creation of a Liquid Crystal (LC) phase in a low molecular weight or polymeric species due to the anisotropy of its attractive and repulsive interactions. The compound containing mesogenic groups (mesogenic compound) does not necessarily have to have an LC phase per se. The mesogenic compounds are capable of exhibiting LC phase behaviour only after mixing with other compounds and/or after polymerization. Typical mesogenic groups are for example rigid rod-like or disk-like units. The terms and definitions used in connection with mesogenic or LC compounds are given in Pure appl.chem.2001,73 (5), 888 and C.Tschierske, G.Pelzl, S.Diele, angew.Chem.2004,116,6340-6368.

As used herein, the term "spacer group" (hereinafter also referred to as "Sp") is known to those skilled in the art and is described in the literature, see, e.g., pure appl. Chem.2001,73 (5), 888 and C.Tschierske, G.Pelzl, S.Diele, angew.Chem.2004,116,6340-6368. As used herein, the term "spacer group" or "spacer group" means a flexible group, e.g., it is an alkylene group, which connects the mesogenic group in the polymerizable mesogenic compound with the polymerizable group.

In the above and in the following text,

represents a trans-1, 4-cyclohexylidene ring, and

represents a 1, 4-phenylene ring.

"organic group" in this context means a carbon or hydrocarbon group.

"carbon group" means a mono-or polyvalent organic group containing at least one carbon atom, wherein the group contains no other atoms (e.g., -C≡C-) or optionally one or more other atoms, such as N, O, S, B, P, si, se, as, te or Ge (e.g., carbonyl, etc.). The term "hydrocarbyl group" means a carbon group that additionally contains one or more H atoms and optionally one or more heteroatoms, such as N, O, S, B, P, si, se, as, te or Ge.

"halogen" means F, cl, br or I.

-CO-, -C (=o) -and-C (O) -represent carbonyl, i.e

-CS-, -C (=s) -and-C (S) -represent thiocarbonyl, i.e

The carbon or hydrocarbon group may be a saturated or unsaturated group. The unsaturated group is, for example, an aryl, alkenyl or alkynyl group. The carbon or hydrocarbon groups having more than 3C atoms may be linear, branched, and/or cyclic and may also contain spiro or fused rings.

The terms "alkyl", "aryl", "heteroaryl" and the like also include multivalent groups such as alkylene, arylene, heteroarylene and the like.

The term "aryl" means an aromatic carbon group or a group derived therefrom. The term "heteroaryl" denotes an "aryl" group as defined above comprising one or more heteroatoms (preferably selected from N, O, S, se, te, si and Ge).

Preferred carbon and hydrocarbon groups are optionally substituted, straight-chain, branched or cyclic alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy having from 1 to 40, preferably from 1 to 20, very preferably from 1 to 12, C atoms, optionally substituted aryl or aryloxy having from 5 to 30, preferably from 6 to 25, C atoms, or optionally substituted alkylaryl, arylalkyl, alkylaryl, arylalkyloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy having from 5 to 30, preferably from 6 to 25, C atoms, wherein one or more C atoms may also be replaced by heteroatoms, preferably selected from N, O, S, se, te, si and Ge.

Further preferred carbon and hydrocarbon groups are C ₁ -C ₂₀ Alkyl, C ₂ -C ₂₀ Alkenyl, C ₂ -C ₂₀ Alkynyl, C ₃ -C ₂₀ Allyl, C ₄ -C ₂₀ Alkyldienyl, C ₄ -C ₂₀ Polyalkenyl, C ₆ -C ₂₀ Cycloalkyl, C ₄ -C ₁₅ Cycloalkenyl, C ₆ -C ₃₀ Aryl, C ₆ -C ₃₀ Alkylaryl, C ₆ -C ₃₀ Aralkyl, C ₆ -C ₃₀ Alkyl aryloxy, C ₆ -C ₃₀ Arylalkoxy, C ₂ -C ₃₀ Heteroaryl, C ₂ -C ₃₀ A heteroaryloxy group.

Particularly preferred is C ₁ -C ₁₂ Alkyl, C ₂ -C ₁₂ Alkenyl, C ₂ -C ₁₂ Alkynyl, C ₆ -C ₂₅ Aryl and C ₂ -C ₂₅ Heteroaryl groups.

Other preferred carbon and hydrocarbon radicals are straight-chain, branched or cyclic alkyl radicals having from 1 to 20, preferably from 1 to 12, C atoms, which are unsubstituted or monosubstituted or polysubstituted by F, cl, br, I or CN and in which one or more of them are not adjacent CH ₂ The groups can each be replaced independently of one another by the following groups in such a way that the O and/or S atoms are not directly connected to one another: -C (R) ^S1 )＝C(R ^S1 )-、-C≡C-、-N(R ^S1 ) -, -O-, -S-; -CO-, -CO-O-, -O-CO-, -O-CO-O-, -and and is also provided with

R ^S1 H, F, cl, CN, a linear, branched or cyclic alkyl chain having from 1 to 25C atoms, wherein, in addition, one or more non-adjacent C atoms may be replaced by-O-, -S-, -CO-, -CO-O-, -O-CO-O-substitution, and wherein one or more H atoms may be replaced by F or Cl, or represents an optionally substituted aryl or aryloxy group having 6 to 30C atoms, or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 30C atoms.

Preferred alkyl groups are, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, trifluoromethyl, perfluoro-n-butyl, 2-trifluoroethyl, perfluoro-octyl, perfluorohexyl and the like.

Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl and the like.

Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl and the like.

Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxyethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, 2-methylbutoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy, n-nonoxy, n-decoxy, n-undecoxy, n-dodecoxy and the like.

Preferred amino groups are, for example, dimethylamino, methylamino, methylphenylamino, phenylamino, and the like.

Aryl and heteroaryl groups may be monocyclic or polycyclic, i.e., they may contain one ring (e.g., phenyl) or two or more rings, which may also be fused (e.g., naphthyl) or covalently bonded (e.g., biphenyl), or comprise a combination of fused and linked rings. Heteroaryl contains one or more heteroatoms, preferably selected from O, N, S and Se.

Particularly preferred are mono-, bi-or tricyclic aryl groups having 6 to 25C atoms and mono-, bi-or tricyclic heteroaryl groups having 5 to 25 ring atoms, which optionally contain fused rings and are optionally substituted. Further preferred are 5-, 6-or 7-membered aryl and heteroaryl groups, wherein, in addition, one or more CH groups may be replaced by N, S or O in such a way that O atoms and/or S atoms are not directly connected to one another.

Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl, [1,1':3',1 ] "]-terphenyl-2' -yl, naphthyl, anthracenyl, binaphthyl, phenanthryl, 9, 10-dihydro-phenanthryl, pyrene, dihydropyrene,Perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene (spirobifluorene), and the like.

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, 1,2,3, 5-tetrazine or fused groups, such as indole, isoindole, indolizine, indazole, benzimidazole, benzotriazole, purine, naphthazole, phenanthroimidazole, pyridoimidazole, pyrazinoimidazole, quinoxalinoimidazole, benzoxazole, naphthazole, anthracenoxazole, phenanthrooxazole, isoxazole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5, 6-quinoline, benzo-6, 7-quinoline, benzo-7, 8-quinoline, benzisoquinoline, acridine, phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine, quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarboline, phenanthridine, phenanthroline, thieno [2,3b ] thiophene, thieno [3,2b ] thiophene, dithiene, isobenzothiophene, dibenzothiophene, benzothiadiazole thiophene, or a combination of these groups.

The aryl and heteroaryl groups mentioned in the context may also be substituted by alkyl, alkoxy, thioalkyl, fluoro, fluoroalkyl or other aryl or heteroaryl groups.

(non-aromatic) alicyclic groups and heterocyclic groups comprise both saturated rings, i.e. rings containing only single bonds, and partially unsaturated rings, i.e. those which may also contain multiple bonds. The heterocyclic ring contains one or more heteroatoms, preferably selected from Si, O, N, S and Se.

The (non-aromatic) alicyclic and heterocyclic groups may be monocyclic, i.e. contain only one ring (e.g. cyclohexane), or polycyclic, i.e. contain multiple rings (e.g. decalin or bicyclooctane). Saturated groups are particularly preferred. Preference is furthermore given to mono-, bi-or tricyclic groups having 5 to 25 ring atoms which optionally contain fused rings and are optionally substituted. Further preferred are 5-, 6-, 7-or 8-membered carbocyclic groups in which, in addition, one or more C atoms may be replaced by Si and/or one or more CH groups may be replaced by N and/or one or more non-adjacent CH groups ₂ The groups may be replaced by-O-and/or-S-.

Preferred cycloaliphatic and heterocyclic groups are, for example, 5-membered groups, such as cyclopentane, tetrahydrofuran, tetrahydrothiophene, pyrrolidine; 6-membered radicals, such as cyclohexane, silacyclohexane (silane), cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1, 3-dioxane, 1, 3-dithiane, piperidine; 7-membered groups such as cycloheptane; and condensed groups such as tetrahydronaphthalene, decalin, 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-methanoindan-2, 5-diyl.

Preferred substituents are, for example, solubility promoting groups, such as alkyl or alkoxy groups; electron withdrawing groups such as fluorine, nitro or nitrile; or substituents for increasing the glass transition temperature (Tg) of the polymer, in particular bulky groups such as tert-butyl or optionally substituted aryl.

Preferred substituents, hereinafter also referred to as L ^S For example F, cl, br, I, -CN, -NO ₂ 、-NCO、-NCS、-OCN、-SCN、-C(＝O)N(R ^S ) ₂ 、-C(＝O)Y ^S 、-C(＝O)R ^S 、-N(R ^S ) ₂ Straight or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy each having 1 to 25C atoms, wherein one or more H atoms are optionally replaced by F or Cl, optionally substituted silane groups having 1 to 20 Si atoms, orOptionally substituted aryl having 6 to 25, preferably 6 to 15C atoms,

wherein R is ^S Represents H, F, cl, CN, or a linear, branched or cyclic alkyl radical having 1 to 25C atoms, in which one or more non-adjacent CH ₂ The radicals are optionally substituted by-O-, -S-, -CO-, -CO-O-, -O-CO-, O-CO-O-is replaced in such a way that the O-and/or S-atoms are not directly linked to one another, and wherein one or more H atoms are each optionally replaced by F or Cl, and

Y ^S represents halogen, preferably F.

"substituted silyl or aryl" preferably means that it is substituted with halogen, -CN, R ⁰ 、-OR ⁰ 、-CO-R ⁰ 、-CO-O-R ⁰ 、-O-CO-R ⁰ or-O-CO-O-R ⁰ Substitution, wherein R ⁰ Represents H or an alkyl group having 1 to 20C atoms.

Particularly preferred substituents L are, for example, 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 In addition, phenyl is also present.

Preferably +.>

Wherein L has one of the meanings indicated above and r is 0, 1, 2, 3 or 4.

Polymerizable group P, P ^x Or P ^1,2 Is a group suitable for free radical polymerization. Particularly preferred are groups for chain polymerization, in particular those comprising a c=c double bond or-c≡c-triple bond, and groups suitable for ring-opening polymerization, such as oxetanyl or epoxy groups.

Preferred group P, P ^x P ^1,2 Selected from the group consisting ofIs set of (3): CH (CH) ₂ ＝CW ¹ -CO-O-、CH ₂ ＝CW ¹ -CO-、CH ₂ ＝CW ² -(O) _k3 -、CW ¹ ＝CH-CO-(O) _k3 -、CW ¹ ＝CH-CO-NH-、CH ₂ ＝CW ¹ -CO-NH-、CH ₃ -CH＝CH-O-、(CH ₂ ＝CH) ₂ CH-OCO-、(CH ₂ ＝CH-CH ₂ ) ₂ CH-OCO-、(CH ₂ ＝CH) ₂ CH-O-、(CH ₂ ＝CH-CH ₂ ) ₂ N-、(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-, where W ¹ Representation H, F, cl, CN, CF ₃ Phenyl or alkyl having 1 to 5C atoms, especially H, F, cl, CH ₃ Or C ₂ H ₅ ，W ² Represents H or an alkyl radical having 1 to 5C atoms, in particular H, methyl, ethyl or n-propyl, W ³ W and W ⁴ Each independently of the others represents H, cl or alkyl having 1 to 5C atoms, phe represents 1, 4-phenylene, which is optionally substituted by one or more groups L (except P-Sp), k as defined above ₁ 、k ₂ K ₃ Each independently of the others represents 0 or 1, k ₃ Preferably represents 1 and k ₄ Represents an integer of 1 to 10.

Very preferred group P, P ^x P ^1,2 Selected from the group consisting of: CH (CH) ₂ ＝CW ¹ -CO-O-, in particular CH ₂ ＝CH-CO-O-、CH ₂ ＝C(CH ₃ ) -CO-O-and CH ₂ =cf-CO-O-and CH ₂ ＝CH-O-、(CH ₂ ＝CH) ₂ CH-O-CO-and (CH) ₂ ＝CH) ₂ CH-O-。

Other preferred polymerizable groups P, P ^x P ^1,2 Selected from the group consisting of: vinyloxy, acrylate, methacrylate, ethyl acrylate (which isCH ₂ ＝CW ¹ -CO-O-, wherein W ¹ Ethyl), fluoroacrylate and chloroacrylate, most preferably acrylate and methacrylate.

If Sp, sp ^x Or Sp ^1,2 It is preferably selected from the formulae Sp "-X" if it is not a single bond, so that the corresponding group P-Sp-corresponds to the formula P-Sp "-X", wherein

Sp' represents a linear or branched alkylene group having 1 to 40, preferably 1 to 20C atoms, optionally monosubstituted or polysubstituted by F, cl, CN or P, and wherein, in addition, one or more non-adjacent CH(s) ₂ The radicals may each independently of one another be selected from the group consisting of-O-, -S-, -NH-, -N (R) ⁰ )-、-Si(R ⁰ R ⁰⁰ )-、-CO-、-CO-O-、-O-CO-、-O-CO-O-、-S-CO-、-CO-S-、-N(R ⁰⁰ )-CO-O-、-O-CO-N(R ⁰ )-、-N(R ⁰ )-CO-N(R ⁰⁰ ) -, -CH=CH-or-C≡C-with O and/or S atoms not being directly bonded to each other,

x' represents-O-, -S-, -CO-O-, -O-CO-O-, -CO-N (R) ⁰ )-、-N(R ⁰ )-CO-、-N(R ⁰ )-CO-N(R ⁰⁰ )-、-OCH ₂ -、-CH ₂ O-、-SCH ₂ -、-CH ₂ S-、-CF ₂ 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 ⁰ -、-CY ² ＝CY ³ -, -C.ident.C-, -CH=CH-CO-O-; O-CO-ch=ch-, or a single bond,

R ⁰ r is R ⁰⁰ Each independently of the others represents H or an alkyl group having 1 to 20C atoms, and

Y ² y and Y ³ Each independently of the other represents H, F, cl or CN.

X' is preferably-O-, -S-; -CO-, -COO-, -OCO-, -O-COO-, -CO-NR ⁰ -、-NR ⁰ -CO-、-NR ⁰ -CO-NR ⁰⁰ -or a single bond.

Typical spacer groups Sp, sp ^x 、Sp ^1,2 -Sp "-X" -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) ⁰ R ⁰⁰ -O) _p1 -, where p1 is an integer from 1 to 20, q1 is an integer from 1 to 6, and R ⁰ R is R ⁰⁰ Having the meaning indicated above.

Particularly preferred groups Sp, sp ^x 、Sp ^1,2 -Sp "-X" -is- (CH) ₂ ) _p1 -、-(CH ₂ ) _p1 -O-、-(CH ₂ ) _p1 -O-CO-、-(CH ₂ ) _p1 -CO-O-、-(CH ₂ ) _p1 -O-CO-O-, wherein p1 and q1 have the meanings indicated above.

Particularly preferred groups Sp' are in each case straight-chain ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxy ethylene, methyleneoxy butylene, ethylenethio ethylene, ethylene-N-methylimino-ethylene, 1-methylalkylene, ethylene, propylene and butylene.

Detailed description of the invention

The LC medium and method of making the polymer wall of the present invention are significantly superior to prior art materials and methods, such as better phase separation between the polymer wall and LC molecules and formation of stronger and stiffer polymer walls with higher stability to mechanical and/or thermal stresses.

In a method of preparing a polymer wall in an LC display, the following two processes occur simultaneously: a) The polymerizable monomer polymerizes in the LC medium by chain growth, and b) phase separation between LC molecules and growing polymer chains occurs. However, the polymerization reaction is generally much faster and typically in the range of milliseconds, while the phase separation is much slower and typically in the range of minutes.

The use of RAFT agents is expected to slow down the chain growth reaction and thereby equalize the time scale of the two processes. This is expected to enable a higher degree of phase separation and allow the use of higher amounts of di-or poly-reactive monomers to form polymer walls with higher stability and mechanical strength.

The RAFT agent is preferably selected from thiocarbonyl compounds, very preferably dithioesters, di-or trithiocarbonates, di-or trithiocarbamates, dithiobenzoate esters and xanthates.

Suitable RAFT reagents are available from, for example, sigma-Aldrich and are also described in literature, for example in the following brochures and articles cited therein:

preferably, the RAFT agent is selected from formula I

Wherein the individual radicals independently of one another and identically or differently at each occurrence have the following meanings:

X ¹ is-S-R ^b 、-O-R ^b 、-N(R ^b R ^c ) Or aryl or heteroaryl having 5 to 20 ring atoms, optionally substituted with L,

R ^a is a linear or branched or cyclic alkyl radical having 1 to 60C atoms, which is optionally fluorinated, and in which one or more CH' s ₂ The radicals optionally being formed by-C (R ⁰ )＝C(R ⁰⁰ )-、-C≡C-、-N(R ⁰ ) -, -O-, -S-; -CO-or-CS-or from polyglycol chains- (CH) ₂ CH ₂ O) _n -in such a way that the O and/or S atoms are not directly connected to each other, and wherein one or more H atoms are optionally represented by F, cl, br, I, CN or N ₃ Or by a heterocyclic, aromatic or heteroaromatic group having 5 to 20 ring atoms, optionally substituted by one or more groups L, or R ^a Is an aryl or heteroaryl group having 5 to 20 ring atoms, preferably phenyl, optionally substituted by one or more groups L,

R ^b 、R ^c is H or has a specific meaning to R ^a One of the meanings given, or R ^b R is R ^c Together with the N atom to which it is attached, may also form an optionally L-substituted heterocyclic or heteroaromatic group having 5 to 8 ring atoms.

L is F, cl, -CN, -NO ₂ 、-NCO、-NCS、-OCN、-SCN、-C(＝O)N(R ^q ) ₂ 、-C(＝O)Y ^z 、-C(＝O)R ^q 、-N(R ^q ) ₂ Optionally substituted silyl, optionally substituted aryl or heteroaryl having 5 to 20 ring atoms or straight-chain or branched alkyl having 1 to 25C atoms, wherein in addition one or more non-adjacent CH ₂ The radicals may each, independently of one another, be derived from-C (R ⁰ )＝C(R ⁰⁰ )-、-C≡C-、-N(R ⁰ ) -, -O-, -S-, -CO-, -CS-; -CO-O-, -O-CO-, O-CO-O-is replaced in such a way that O and/or S atoms are not directly connected to one another, and wherein, in addition, one or more H atoms may be replaced by F, cl, -CN,

R ^q h, F, cl, CN or a linear, branched or cyclic alkyl radical having 1 to 25C atoms, in which one or more non-adjacent CH ₂ The radicals optionally being composed of-O-, -S-, -CO-, -CO-O-, -O-CO-, O-CO-O-is replaced in such a way that the O-and/or S atoms are not directly connected to one another, and wherein one or more H atoms are each optionally replaced by F or Cl,

R ⁰ 、R ⁰⁰ Is H or an alkyl group having 1 to 20C atoms,

Y ^z is halogen, preferably F or Cl,

n is an integer > 1, preferably 1 to 300 or 1 to 12.

Very preferably, the RAFT agent is selected from the following subformulae:

R ^a 、R ^b 、R ^c having one of the meanings given in formula I,

R ^d is a linear or branched alkylene group having 2 to 30C atoms, wherein one or more CH ₂ The radicals optionally being composed of-O-, -CO-or- (CH) ₂ CH ₂ O) _n Substituted, and wherein one or more H atoms are optionally replaced by CN,

R ^e is a linear or branched or cyclic alkyl radical having 1 to 20C atoms, which is optionally fluorinated, and in which one or more CH' s ₂ The radicals optionally being formed by-C (R ⁰ )＝C(R ⁰⁰ )-、-C≡C-、-N(R ⁰ ) -, -O-, -S-; -CO- -CS-or- (CH) ₂ CH ₂ O) _n In such a way that O and/or S atoms are not directly connected to each other, and in which one or more H atoms may be represented by F, cl, br, I, CN or N ₃ Or by a heterocyclic, aromatic or heteroaromatic group having 5 to 20 ring atoms, optionally substituted by one or more groups L, or R ^c1 Is an aryl or heteroaryl group having 5 to 20 ring atoms, preferably phenyl, optionally substituted by one or more groups L,

ar is aryl or heteroaryl having 5 to 8 ring atoms, very preferably phenyl, optionally substituted by one or more radicals L as defined in formula I,

n is an integer > 1, preferably 1 to 300 or 1 to 12.

More preferably, the RAFT agent is selected from the following subformulae:

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R ^a1 h, R of a shape of H, R ^b1 、-(CH ₂ CH ₂ O) _n -CH ₃ Phenyl, pentafluorophenyl or

R ^a2 H, R of a shape of H, R ^b1 A phenyl group or a CN group,

R ^b1 is a linear or branched alkyl radical having 1 to 20C atoms, wherein one or more H atoms are optionally selected from OH, CN or N ₃ Instead of the above-mentioned, the method,

R ^d1 is alkylene having 2 to 20C atoms or- (CH) ₂ CH ₂ O) _n -，

Y ³ 、Y ⁴ H, CH of a shape of H, CH ₃ The group consisting of CN and phenyl,

l has one of the meanings given in formula I,

k is 0 or 1, and the number of the groups is,

n is an integer > 1, preferably 1 to 300 or 1 to 12,

r is 0, 1, 2, 3 or 4,

s is 0, 1 or 2.

In the above formulae, preferably, Y ³ Y and Y ⁴ And not both CN. Very preferably Y ³ Y and Y ⁴ One of them is CH ₃ And the other is CN, or Y ³ Y and Y ⁴ Both are CH ₃ Or Y ³ Y and Y ⁴ One of them is H and the other is CH ₃ Or CN, or Y ³ Y and Y ⁴ Both are H, or Y ³ Y and Y ⁴ One of which is H and the other is phenyl.

Further preferably, if Y in the above formulae ³ Y and Y ⁴ One of them is CN, R ^a2 Not CN.

Most preferably, the RAFT agent is selected from the following subformulae:

/>

wherein n is as defined above.

In a preferred embodiment, the polymerisable component a comprises two or more RAFT agents preferably selected from formula I and its preferred subformulae.

The concentration of RAFT agent in the LC medium is preferably 0.01% to 10%, very preferably 0.1% to 8%, most preferably 0.1% to 5%.

Preferably, the polymerizable compound of component a is selected from compounds having one, two, three or four polymerizable groups, more preferably compounds having one, two or three polymerizable groups, most preferably compounds having one or two polymerizable groups.

Preferably, the polymerizable component A comprises

One or more first polymerizable compounds comprising a linear or branched hydrocarbon group having 1 to 30C atoms or a monocyclic hydrocarbon group having 3 to 24 ring atoms or a bicyclic or polycyclic hydrocarbon group having 4 to 30 ring atoms and (exactly) one polymerizable group attached thereto, and

one or more second polymerizable compounds comprising a linear, branched, or cyclic hydrocarbon group having 1 to 30C atoms and two or more polymerizable groups attached thereto.

Preferably, component a of the LC medium comprises one or more first polymerizable compounds selected from formula II:

P-Sp-G ¹ II

p is a polymerizable group and is preferably a polymerizable group,

sp is a spacer group or a single bond,

G ¹ is a linear or branched alkyl radical having from 1 to 20C atoms or a monocycloalkyl radical having from 3 to 24C atoms, which is optionally mono-, poly-or perfluorinated and is optionally substituted by one or more radicals L, and in which one or more CH's are present ₂ The radicals optionally being composed of-O-, -CO-, O-CO-or-CO-O-is replaced in such a way that O atoms are not directly adjacent to one another,

l is F, cl, -CN, -NO ₂ 、-NCO、-NCS、-OCN、-SCN、-C(＝O)N(R ^q ) ₂ 、-C(＝O)Y ^z 、-C(＝O)R ^q 、-N(R ^q ) ₂ Optionally substituted silyl, optionally substituted aryl or heteroaryl having 5 to 20 ring atoms or straight-chain or branched alkyl having 1 to 25C atoms, wherein in addition one or more non-adjacent CH ₂ The radicals may each, independently of one another, be derived from-C (R ⁰ )＝C(R ⁰⁰ )-、-C≡C-、-N(R ⁰ ) -, -O-, -S-, -CO-; -CO-O-, -O-CO-, O-CO-O-is replaced in such a way that O and/or S atoms are not directly connected to one another, and wherein, in addition, one or more H atoms may be replaced by F, cl, -CN,

R ⁰ 、R ⁰⁰ Is H or an alkyl group having 1 to 20C atoms,

Y ^z halogen, preferably F or Cl.

P is preferably an acrylate or methacrylate.

Sp preferably has the formula Sp "-X", such that each group P-Sp-corresponds to the formula P-Sp "-X" -, where Sp "and X" are as defined above.

Sp is very preferably- (CH) ₂ ) _p1 -、-(CH ₂ ) _p1 -O-、-(CH ₂ ) _p1 -O-CO-、-(CH ₂ ) _p1 -CO-O-、-(CH ₂ ) _p1 -O-CO-O-, wherein p1 is an integer from 1 to 12.

L is preferably selected from F, cl, -CN and straight-chain or branched alkyl radicals having from 1 to 25, particularly preferably from 1 to 10, C atoms, in addition to one or more non-adjacent CH' s ₂ The groups can each be replaced independently of one another by the following groups in such a way that the O and/or S atoms are not directly connected to one another: -C (R) ⁰ )＝C(R ⁰⁰ )-、-C≡C-、-N(R ⁰ ) -, -O-, -S-; -CO-, -CO-O-, -O-CO-, -O-CO-O-, -and and furthermore wherein one or more H atoms may be replaced by: F. cl, br, I or CN.

L is very preferably selected from F, -CN and optionally fluorinated alkyl or alkoxy groups having 1 to 6C atoms, preferably F, cl, CN, CH ₃ 、OCH ₃ 、OCF ₃ 、OCF ₂ H or OCFH ₂ F is very preferred.

Preferred compounds of formula II are selected from the following formulae:

P-Sp-(CHW ¹¹ ) _n2 -(CH ₂ ) _n1 -(CHW ¹² ) _n3 -CH ₃ II1

P-Sp-(CH ₂ ) _n2 -(CF ₂ ) _n1 -CFW ¹³ W ¹⁴ II2

wherein the individual radicals independently of one another and identically or differently at each occurrence have the following meanings

P, sp has the meaning given in formula II or one of the preferred meanings given above and below,

W ¹¹ 、W ¹² Is H, F or straight-chain or branched C ₁ -C ₁₂ -an alkyl group, which is a group,

W ¹³ 、W ¹⁴ is H or F, and is not limited to the above,

n1 is an integer of 2 to 15,

n2, n3 are 0 or an integer from 1 to 3.

Highly preferred compounds of formula II are selected from the following formulae:

CH ₂ ＝CW-CO-O-(CHW ¹¹ ) _n2 -(CH ₂ ) _n1 -(CHW ¹² ) _n3 -CH ₃ II1a

CH ₂ ＝CW-CO-O-(CH ₂ ) _n2 -(CF ₂ ) _n1 -CFW ¹³ W ¹⁴ II2a

wherein W is H, CH ₃ Or C ₂ H ₅ And W is ¹¹ 、W ¹² 、W ¹³ 、W ¹⁴ N1, n2 and n3 are as defined in formulae II1 and II2, n4 is 0 or an integer from 1 to 15, s is 0 or 1, and n4 is not 0 if s is 1.

Other preferred compounds of formula II are selected from the following formulae:

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in another preferred embodiment of the invention, component a of the LC medium comprises one or more first polymerisable compounds comprising a polymerisable group and a bicyclic or polycyclic hydrocarbon group having 4 to 30 ring atoms, preferably 6 to 25 ring atoms, preferably a non-aromatic hydrocarbon group.

Preferably, component A of the LC medium according to this preferred embodiment comprises, in addition to or alternatively to the compound of formula II, one or more polymerizable compounds selected from the group consisting of formula IIA

P-Sp-G ² IIA

Wherein P and Sp have the meanings given in formula II or one of the preferred meanings given above and below, and

G ² is a bicyclic or polycyclic hydrocarbon radical, preferably a bridged or fused bicyclic or polycyclic alkyl radical, having from 4 to 30 ring atoms, preferably from 6 to 25 ring atoms, optionally substituted by one or more radicals L as defined in formula II.

Preferably, a bicyclic or polycyclic hydrocarbon group or group G ² Is a di-, tri-or tetracyclic group.

Preferably, a bicyclic or polycyclic hydrocarbon group or group G ² Is a bridged bicyclic or polycyclic hydrocarbon radical, i.e. it consists of a fused hydrocarbon ring, preferably a fused cycloalkyl ring, in which the fusion of the sequences of spanning atoms (bridgehead), preferably bipedal bridge, is carried out, for example, in bicyclo [2.2.1 ]]Heptane (norbornane), bicyclo [2.2.2]Octane or tricyclo [3.3.3.1 ]]Decane (adamantane).

In another aspect of the inventionIn a preferred embodiment, the bicyclic or polycyclic hydrocarbon radicals or radicals G ^2A Is a fused bicyclic or polycyclic hydrocarbon radical, i.e. it consists of a fused hydrocarbon ring, preferably a fused cycloalkyl ring, in which the fusion takes place across the bond between two atoms, as in bicyclo [3.2.0 ]]Heptane or bicyclo [4.4.0 ]]Decane (decalin).

In yet another preferred embodiment of the invention, the bicyclic or polycyclic hydrocarbon radicals or radicals G ² Is a spiro group, i.e. it consists of a fused hydrocarbon ring, preferably a fused cycloalkyl ring, wherein the fusion is carried out at a single atom (spiro atom), as in spiro [3.3 ]]Heptane or spiro [4.5 ]]Decane.

Bicyclic or polycyclic radicals or radicals G ² Optionally substituted with one or more substituents preferably selected from the group L as defined above and below.

Preferably, a bicyclic or polycyclic group or group G ² Selected from the group consisting of: bicyclo [1.1.1]Amyl, bicyclo [2.1.1 ]]Hexyl, bicyclo [2.2.1]Heptyl (norbornyl), bicyclo [3.2.1]Octyl, bicyclo [2.2.2]Octyl, bicyclo [3.2.2]Nonyl, bicyclo [3.3.1]Nonyl, bicyclo [3.3.2]Decyl, bicyclo [3.3.3]Undecyl, tricyclo [3.3.3.1 ]]Decyl (adamantyl), tricyclo [5.2.1.0]Decyl (tetrahydrodicyclopentadienyl), bicyclo [2.1.0 ]]Amyl, bicyclo [2.2.0 ]]Hexyl, bicyclo [3.2.0]Heptyl, bicyclo [4.2.0]Octyl, bicyclo [3.3.0]Octyl, bicyclo [4.3.0]Nonyl, bicyclo [4.4.0]Decyl (decalin), spiro [2.2 ]]Amyl, spiro [3.2 ]]Hexyl, spiro [3.3 ]]Heptyl, spiro [4.3 ]]Octyl, spiro [4.4 ]]Nonyl, spiro [4.5 ]]Decyl, all optionally substituted with one or more groups L as defined in formula I.

Very preferably, a bicyclic or polycyclic group or group G ² Selected from the group consisting of: bicyclo [1.1.1]Amyl, bicyclo [2.1.1 ]]Hexyl, bicyclo [2.2.1]Heptyl (norbornyl), bicyclo [3.2.1]Octyl, bicyclo [2.2.2]Octyl, bicyclo [3.2.2]Nonyl, bicyclo [3.3.1]Nonyl, bicyclo [3.3.2]Decyl, bicyclo [3.3.3]Undecyl, tricyclo [3.3.3.1 ] ]Decyl (adamantyl), all optionally substituted with one or more groups L as defined in formula I.

Most preferably, bicyclic or polycyclic groups or radicalsGroup G ² Selected from the group consisting of: bicyclo [2.2.1]Heptyl (norbornyl), bicyclo [2.2.2]Octyl, tricyclo [3.3.3.1 ]]Decyl (adamantyl), all optionally substituted with one or more groups L as defined above and below.

Preferred compounds of formula IIA are selected from the following formulae

Wherein R, identically or differently at each occurrence, represents P-Sp-or has the meaning given above for R ^q One of the meanings given and one group R in each of the formulae IIAA-IIAC represents P-Sp-.

Other preferred compounds of formula IIA are selected from the following formulae:

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wherein P and Sp have the meanings given in formula IIA or one of the preferred meanings given above, W ¹¹ 、W ¹² W and W ¹³ H, F or C independently of one another ₁ -C ₁₂ -alkyl, preferably methyl, and cycloalkyl optionally substituted with one or more groups L as defined above.

Very preferred compounds of formula IIA are selected from the following formulae:

wherein n is 0 or an integer from 1 to 8, W is H, CH ₃ Or C ₂ H ₅ And W is ¹¹ 、W ¹² W and W ¹³ Is H, F or C ₁ -C ₁₂ -alkyl, preferably methyl.

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Preferably, component a of the LC medium comprises one or more second polymerizable compounds selected from formula III:

P ¹ -Sp ¹ -G ³ -Sp ² -P ² III

P ¹ p ² In the form of a polymerizable group, the polymerizable group,

Sp ¹ 、Sp ² is a spacer group or a single bond,

G ³ is a linear, branched or cyclic alkyl radical having 1 to 20C atoms, which is optionally mono-, poly-or perfluorinated and optionally via one or more groups P ¹ -Sp ¹ -or one or more groups L as defined in formula II, and wherein one or more CH ₂ The radicals optionally being composed of-O-, -CO-, -O-CO-or-CO-O-is replaced in such a way that the O atoms are not directly adjacent to each other.

P ¹ P ² Preferably selected from the group consisting of acrylate, methacrylate, ethyl acrylate and vinyloxy.

Sp in formula III ¹ Sp and Sp ² Preferably a single bond.

If the hydrocarbon group or group G in the second polymerizable compound ³ Is a cyclic group, it is preferably one which preferably has 5 to 7 ring atoms and is optionally substituted by one or more groups of the formula IIDefined groups L are monocyclic cycloalkyl groups substituted.

In another preferred embodiment of the invention, the hydrocarbon group or group G in the second polymerizable compound ³ Is a di-, tri-or tetracyclic group, and preferably has 4 to 30C atoms, optionally substituted with one or more groups L as defined above and below. Preferred di-, tri-or tetracyclic groups or groups G in the second polymerizable compound ³ Is a group G of formula IIA ^2A Or one of the meanings given above as preferred.

Preferred compounds of formula III are selected from the following formulae:

P ¹ -Sp ¹ -(CHW ¹¹ ) _n2 -(CH ₂ ) _n1 -(CHW ¹² ) _n3 -Sp ² -P ² III1

P ¹ -(CH ₂ ) _n2 -(CF ₂ ) _n1 -(CH ₂ ) _n3 -P ² III3

(P ¹ -Sp ¹ -(CH ₂ ) _n4 ) _n5 CH _4-n5 III4

wherein P is ¹ 、P ² 、Sp ¹ 、Sp ² As defined in the description of the formula III,

W ¹¹ 、W ¹² at each occurrence, are the same or different H, F or C ₁ -C ₁₂ -an alkyl group, which is a group,

n1 is an integer of 2 to 15,

n2, n3 are each independently of the other 0 or an integer from 1 to 3,

n4 is 0 or an integer from 1 to 15,

n5 is 3 or 4 and is preferably selected from the group consisting of,

and the cyclohexylene ring in formula III2 is optionally interrupted by one or more identical or different radicals W ¹¹ And (3) substitution.

In a preferred embodiment of the present invention,component a of the LC medium includes one or more second polymerizable compounds, wherein the two polymerizable groups are different from each other. Preferably, in this preferred embodiment, component A of the LC medium comprises one or more compounds of formula III or a subformula thereof, wherein P ¹ P ² Different from each other. Preferably, in these compounds of formula III, P ¹ P ² One of which is vinyloxy and the other is acrylate, methacrylate or ethyl acrylate, most preferably methacrylate.

In a further preferred embodiment of the invention, component A of the LC medium comprises one or more compounds of the formula III or a subformula thereof, where P ¹ P ² Are the same groups.

In the third polymerizable compound, the polymerizable group is preferably selected from the group consisting of acrylate, methacrylate, ethyl acrylate, and vinyloxy. Very preferably, one of the polymerizable groups is a vinyloxy group and the other is an acrylate or methacrylate, most preferably a methacrylate.

Very preferred compounds of formula III are selected from the following formulae:

CH ₂ ＝CW-CO-O-(CHW ¹¹ ) _n4 -(CH ₂ ) _n1 -O-CH＝CH ₂ III1a

CH ₂ ＝CH-O-(CHW ¹¹ ) _n4 -(CH ₂ ) _n1 -O-CO-CW＝CH ₂ III1b

CH ₂ ＝CW-CO-O-(CHW ¹¹ ) _n2 -(CH ₂ ) _n1 -(CHW ¹² ) _n3 -O-CO- III1c

CW＝CH ₂

/>

CH ₂ ＝CW-CO-O-(CH ₂ ) _n2 -(CF ₂ ) _n1 -(CH ₂ ) _n3 -O-CH＝CH ₂ III3a

CH ₂ ＝CW-CO-O-(CH ₂ ) _n2 -(CF ₂ ) _n1 -(CH ₂ ) _n3 -O-CO-CW＝CH ₂ III3b

(CH ₂ ＝CW-CO-O-(CH ₂ ) _n2 ) ₃ CH III4a

(CH ₂ ＝CW-CO-O-(CH ₂ ) _n2 ) ₄ C III4b

wherein W is H, CH ₃ Or C ₂ H ₅ And W is ¹¹ 、W ¹² N1, n2 and n4 are as defined in formulae III1 to III4, and the cyclohexylene ring in formulae III2a to c is optionally interrupted by one or more identical or different radicals W ¹¹ And (3) substitution.

Other preferred compounds of formula III are selected from the following formulae:

/>

in another preferred embodiment of the invention, component a of the LC medium additionally comprises one or more third polymerizable compounds comprising a cinnamate group wherein the O atom is linked to an acrylate or methacrylate group via a hydrocarbon spacer group having 2 to 20C atoms.

Preferably, the third polymerizable compound having a cinnamate group is selected from formula IV:

P ^x is an acrylate or methacrylate group and is selected from the group consisting of,

Sp ^x is a linear, branched or cyclic alkylene radical having from 2 to 20C atoms, in which one or more non-adjacent CH ₂ The radicals optionally being formed by-O-; -S-, -CO-,-CO-O-, -O-CO-, O-CO-O-is replaced in such a way that the O-and/or S atoms are not directly connected to one another,

R ^x h, F, cl, CN, P of a shape of H, F, cl, CN, P ^x 、P ^x -Sp ^x -、R ^y 、R ^y -O-CO-CH＝CH-、P ^x -Sp ^x -O-CO-CH＝CH-、R ^y -CH＝CH-CO-O-、P ^x -Sp ^x -CH＝CH-CO-O-，

R ^y Is a linear, branched or cyclic alkyl group having 1 to 25C atoms, wherein one or more non-adjacent CH ₂ The radicals optionally being selected from-O-, -S-, -NR ⁰ -、-CO-、-CO-O-、-O-CO-、-O-CO-O-、-C(R ⁰ )＝C(R ⁰⁰ ) or-C.ident.C-is replaced by O-and/or S atoms which are not directly linked to one another and in which one or more H atoms are each optionally replaced by F or Cl,

A ^x is an aromatic, heteroaromatic, cycloaliphatic or heterocyclic radical having from 4 to 25 ring atoms which may also contain fused rings and is unsubstituted or monosubstituted or polysubstituted by L,

Z ^x is-O-, -S-, -CO-O-, and-OCO-, -O-CO-O-, -OCH ₂ -、-CH ₂ O-、-SCH ₂ -、-CH ₂ S-、-CF ₂ O-、-OCF ₂ -、-CF ₂ S-、-SCF ₂ -、-(CH ₂ ) _n11 -、-CF ₂ CH ₂ -、-CH ₂ CF ₂ -、-(CF ₂ ) _n11 -、-CH＝CH-、-CF＝CF-、-C≡C-、-CH＝CH-COO-、-OCO-CH＝CH-、CR ⁰ R ⁰⁰ Or a single bond,

l is F, cl, -CN, -NO ₂ 、-NCO、-NCS、-OCN、-SCN、-C(＝O)N(R ^q ) ₂ 、-C(＝O)Y ^z 、-C(＝O)R ^q 、-N(R ^q ) ₂ Optionally substituted silyl, optionally substituted aryl or heteroaryl having 5 to 20 ring atoms or straight-chain or branched alkyl having 1 to 25C atoms, wherein in addition one or more non-adjacent CH ₂ The radicals may each, independently of one another, be derived from-C (R ⁰ )＝C(R ⁰⁰ )-、-C≡C-、-N(R ⁰ )-、-O-、-S-、-CO-、-CO-O-、-O-CO-, -O-CO-O-, and O and/or S atoms are not directly connected to each other, and wherein, in addition, one or more H atoms may be replaced by F, cl, -CN,

R ⁰ 、R ⁰⁰ is H or an alkyl group having 1 to 20C atoms,

Y ^z is halogen, preferably F or Cl,

m1 is 0, 1 or 2,

n11 is 1, 2, 3 or 4.

In a preferred embodiment of the invention, R ^x Selected from P ^x 、P ^x -Sp ^x -、P ^x -Sp ^x -O-CO-ch=ch-and P ^x -Sp ^x -ch=ch-CO-O-, wherein P ^x Sp and Sp ^x As defined in the context.

In another preferred embodiment of the present invention, R ^x Is a linear, branched or cyclic alkyl radical having 1 to 25C atoms, wherein one or more non-adjacent CH ₂ The radicals optionally being selected from-O-, -S-, -NR ⁰ -, -CO-O-; -O-CO-O-CO-O-is replaced in such a way that the O-and/or S atoms are not directly connected to one another, and wherein one or more H atoms are each optionally replaced by F or Cl.

Sp ^x Preferably selected from- (CH) ₂ ) _p1 -、-(CH ₂ ) _p1 -O-、-(CH ₂ ) _p1 -O-CO-、-(CH ₂ ) _p1 -CO-O-or- (CH) ₂ ) _p1 -O-CO-O-, wherein p1 is an integer from 2 to 12, and wherein Sp ^x To the radicals P in such a way that O atoms are not directly connected to each other ^x Or cinnamate groups.

In a preferred embodiment of the invention, m1 is 0. In another preferred embodiment of the invention, m1 is 1 or 2.

A ^x Preferably selected from 4-phenylene, 1, 3-phenylene, naphthalene-1, 4-diyl, naphthalene-2, 6-diyl, phenanthrene-2, 7-diyl, 9, 10-dihydro-phenanthrene-2, 7-diyl, anthracene-2, 7-diyl, fluorene-2, 7-diyl, coumarin-yl, flavone (in addition, in which one or more CH groups of these groups may be replaced by N), cyclohexane-1, 4-diyl (in addition, in which one or more non-adjacent CH groups ₂ Groups may be replaced by O and/or S), 1, 4-cyclohexenylene, bicyclo [1.1.1]Pentane-1, 3-diyl, bicyclo [2.2.2]Octane-1, 4-diyl, spiro [3.3 ]]Heptane-2, 6-diyl, piperidine-1, 4-diyl, decalin-2, 6-diyl, 1,2,3, 4-tetrahydronaphthalene-2, 6-diyl, indan-2, 5-diyl or octahydro-4, 7-methanoindan-2, 5-diyl, wherein all these groups may be unsubstituted or mono-or polysubstituted by L as defined hereinabove.

Very preferably, A ^x Selected from 1, 4-phenylene, naphthalene-2, 6-diyl and cyclohexane-1, 4-diyl, which is unsubstituted or mono-or polysubstituted by L as defined hereinabove.

Z ^x Preferably selected from the group consisting of-CO-O-; -OCO-, -OCH ₂ -、-CH ₂ O-、-CF ₂ O-、-OCF ₂ -、-CF ₂ S-、-(CH ₂ ) _n11 -, -CH=CH-, -CF=CF-, -C≡C-, -CH=CH-COO-, -OCO-CH=CH-, or a single bond.

Preferred compounds of formula IV are selected from the following formulae:

/>

wherein P is ^x 、Sp ^x 、R ^x And L has one of the meanings given in formula IV or the preferred meanings given in the context, and r is0. 1, 2, 3 or 4.

Very preferred are compounds of formulae IV1-IV 4.

In the formulae IV1 to IV12, R ^x Preferably represents F, cl, CN or a linear, branched or cyclic alkyl radical having from 1 to 25, preferably from 1 to 12, C atoms, in which one or more non-adjacent CH ₂ The radicals optionally being composed of-O-, -S-, -CO-, -CO-O-, -O-CO-, O-CO-O-is replaced in such a way that the O-and/or S atoms are not directly connected to one another, and wherein one or more H atoms are each optionally replaced by F or Cl.

Very preferred compounds of formula IV are selected from the following formulae:

/>

other preferred are compounds of formulae IV1-IV4b wherein the acrylate groups are replaced by methacrylate groups.

In a further preferred embodiment of the invention, component a of the LC medium additionally comprises one or more fourth polymerizable compounds comprising maleimide groups, preferably selected from the group consisting of formula V:

R ^d -Sp ^y -(A ^y -Z ^y ) _m1 -Sp ^y -R ^e V

R ^d 、R ^e H, F, cl, CN, P of a shape of H, F, cl, CN, P ^y Or R is ^z Wherein R is ^d R is R ^e At least one of which is P ^y ，

P ^y Is that/>

Sp ^y Is 1 to 1A linear, branched or cyclic alkylene group of 20C atoms, wherein one or more of the non-adjacent CH' s ₂ The radicals optionally being composed of-O-, -S-, -CO-, -CO-O-, -O-CO-, O-CO-O-is replaced in such a way that the O-and/or S atoms are not directly connected to one another, or a single bond,

R ^m 、R ⁿ is H or an alkyl group having 1 to 5C atoms,

R ^z is a linear, branched or cyclic alkyl group having 1 to 25C atoms, wherein one or more non-adjacent CH ₂ The radicals optionally being selected from-O-, -S-, -NR ⁰ -、-CO-、-CO-O-、-O-CO-、-O-CO-O-、-C(R ⁰ )＝C(R ⁰⁰ ) -, -C.ident.C-is replaced by O-and/or S atoms which are not directly connected to one another and in which one or more H atoms are each optionally replaced by F or Cl,

A ^y is an aromatic, heteroaromatic, cycloaliphatic or heterocyclic radical having from 4 to 25 ring atoms which may also contain fused rings and is unsubstituted or monosubstituted or polysubstituted by L,

Z ^y is-O-, -S-, -CO-O-, and-OCO-, -O-CO-O-, -OCH ₂ -、-CH ₂ O-、-SCH ₂ -、-CH ₂ S-、-CF ₂ O-、-OCF ₂ -、-CF ₂ S-、-SCF ₂ -、-(CH ₂ ) _n11 -、-CF ₂ CH ₂ -、-CH ₂ CF ₂ -、-(CF ₂ ) _n11 -、-CH＝CH-、-CF＝CF-、-C≡C-、-CH＝CH-COO-、-OCO-CH＝CH-、CR ⁰ R ⁰⁰ Or a single bond,

l is F, cl, -CN, -NO ₂ 、-NCO、-NCS、-OCN、-SCN、-C(＝O)N(R ^q ) ₂ 、-C(＝O)Y ^z 、-C(＝O)R ^q 、-N(R ^q ) ₂ Optionally substituted silyl, optionally substituted aryl or heteroaryl having 5 to 20 ring atoms or straight-chain or branched alkyl having 1 to 25C atoms, wherein in addition one or more non-adjacent CH ₂ The radicals may each, independently of one another, be derived from-C (R ⁰ )＝C(R ⁰⁰ )-、-C≡C-、-N(R ⁰ ) -, -O-, -S-; -CO- -CO-O-, -O-CO-, -O-CO-O-and O and/or S atoms thereofThis non-direct connection, and wherein, in addition, one or more H atoms may be replaced by F, cl, -CN,

R ⁰ 、R ⁰⁰ is H or an alkyl group having 1 to 20C atoms,

Y ^z is halogen, preferably F or Cl,

m1 is 0, 1 or 2,

n11 is 1, 2, 3 or 4.

R ^y Preferably a primary alkyl group having 1 to 12, preferably 1 to 6C atoms, a secondary alkyl group having 3 to 15, preferably 3 to 10C atoms or a tertiary alkyl group having 4 to 18, preferably 4 to 12C atoms.

Sp ^y Preferably- (CH) ₂ ) _p1 -、-(CH ₂ ) _p1 -O-、-(CH ₂ ) _p1 -O-CO-or- (CH) ₂ ) _p1 CO-O-, very preferably- (CH) ₂ ) _p1 -wherein p1 is an integer from 1 to 12.

In a preferred embodiment of the invention, m1 in formula I is 0. In another preferred embodiment of the invention, m1 in formula I is 1 or 2.

A in formula V ^y Preferably selected from 4-phenylene, 1, 3-phenylene, naphthalene-1, 4-diyl, naphthalene-2, 6-diyl, phenanthrene-2, 7-diyl, 9, 10-dihydro-phenanthrene-2, 7-diyl, anthracene-2, 7-diyl, fluorene-2, 7-diyl, coumarin-yl, flavone (in addition, in which one or more CH groups of these groups may be replaced by N), cyclohexane-1, 4-diyl (in addition, in which one or more non-adjacent CH groups ₂ Groups may be replaced by O and/or S), 1, 4-cyclohexenylene, bicyclo [1.1.1]Pentane-1, 3-diyl, bicyclo [2.2.2]Octane-1, 4-diyl, spiro [3.3 ]]Heptane-2, 6-diyl, piperidine-1, 4-diyl, decalin-2, 6-diyl, 1,2,3, 4-tetrahydronaphthalene-2, 6-diyl, indane-2, 5-diyl or octahydro-4, 7-methanoindan-2, 5-diyl, wherein all these groups are unsubstituted or mono-or polysubstituted by L as defined above.

Very preferably, A in formula V ^y Selected from 1, 4-phenylene, naphthalene-2, 6-diyl and cyclohexane-1, 4-diyl, which is unsubstituted or mono-or polysubstituted by L as defined hereinabove.

Z ^y Preferably selected from the group consisting of-CO-O-; -OCO-, -OCH ₂ -、-CH ₂ O-、-CF ₂ O-、-OCF ₂ -、-CF ₂ S-、-(CH ₂ ) _n11 -, -CH=CH-, -CF=CF-, -C≡C-, -CH=CH-COO-, -OCO-CH=CH-, or a single bond.

Preferred compounds of formula V are selected from the following formulae:

/>

wherein R is ^z 、Sp ^y 、A ^y 、Z ^y As defined in the context.

Very preferred compounds of formula v are selected from the following formulae:

in another preferred embodiment of the invention, component a of the LC medium additionally comprises one or more fifth polymerizable compounds comprising a ring system comprising one or more aromatic or heteroaromatic rings or condensed aromatic or heteroaromatic rings and two free radically polymerizable groups attached thereto.

The compound is preferably selected from formula VI:

P ¹ -Sp ¹ -B ¹ -(Z ^b -B ² ) _m -Sp ² -P ² VI

B ¹ b (B) ² Independently of one another and on each occurrence identically or differently are aromatic, heteroaromatic, cycloaliphatic or heterocyclic radicals preferably having from 4 to 25 ring atoms, which may also contain condensed rings, and are unsubstituted or monosubstituted or polysubstituted by L as defined in formula I, wherein B ¹ B (B) ² At least one of which represents an aromatic or heteroaromatic group,

Z ^b at each occurrence identically or differently is-O-, -S-; -CO-, -CO-O-, -OCO-, -O-CO-O-, -OCH ₂ -、-CH ₂ O-、-SCH ₂ -、-CH ₂ S-、-CF ₂ O-、-OCF ₂ -、-CF ₂ S-、-SCF ₂ -、-(CH ₂ ) _n1 -、-CF ₂ CH ₂ -、-CH ₂ CF ₂ -、-(CF ₂ ) _n11 -、-CH＝CH-、-CF＝CF-、-C≡C-、-CH＝CH-COO-、-OCO-CH＝CH-、CR ⁰ R ⁰⁰ Or a single bond,

R ⁰ r is R ⁰⁰ Each independently of the others represents H or an alkyl group having 1 to 20C atoms,

m represents 0, 1, 2, 3 or 4,

n11 represents 1, 2, 3 or 4,

particularly preferred compounds of formula VI are those as follows: b (B) ¹ B (B) ² Each independently of the others represents 1, 4-phenylene, 1, 3-phenylene, naphthalene-1, 4-diyl, naphthalene-2, 6-diyl, phenanthrene-2, 7-diyl, 9, 10-dihydro-phenanthrene-2, 7-diyl, anthracene-2, 7-diyl, fluorene-2, 7-diyl, coumarin-yl, flavone (furthermore, wherein one or more CH groups of these groups may be replaced by N), cyclohexane-1, 4-diyl (furthermore, wherein one or more non-adjacent CH groups are ₂ Groups may be replaced by O and/or S), 1, 4-cyclohexenylene, bicyclo [1.1.1]Pentane-1, 3-diyl, bicyclo [2.2.2]Octane-1, 4-diyl, spiro [3.3 ]]Heptane-2, 6-diyl, piperidine-1, 4-diyl, decalin-2, 6-diyl, 1,2,3, 4-tetrahydronaphthalene-2, 6-diyl, indan-2, 5-diyl or octahydro-4, 7-methanoindan-2, 5-diyl, wherein all these groups may be unsubstituted or mono-or polysubstituted by L as defined hereinabove.

Very particularly preferred are of the formula VIThe compound is wherein B ¹ B (B) ² Each independently of the others represents 1, 4-phenylene, 1, 3-phenylene, naphthalene-1, 4-diyl or naphthalene-2, 6-diyl (which is unsubstituted or mono-or polysubstituted by L as defined hereinabove).

Other preferred compounds of formula VI are selected from the group consisting of the following subformulae:

/>

wherein P is ¹ 、P ² 、Sp ¹ 、Sp ² And L is as defined in formula VI,

Z ¹ is-O-, -CO-, -C (R) ^f R ^g ) -or-CF ₂ CF ₂ -，

R ^f 、R ^g Represent H, F, CH independently of each other ₃ Or CF (CF) ₃ ，

Z ² 、Z ³ Independently of one another, are-CO-O-, -O-CO-, -CH ₂ O-、-OCH ₂ -、-CF ₂ O-、-OCF ₂ -or- (CH) ₂ ) _n11 -, where n11 is 2, 3 or 4,

r is 0, 1, 2, 3 or 4,

s is 0, 1, 2 or 3,

t is 0, 1 or 2.

Particularly preferred are the di-reactive compounds of formulae VI2 and VI 3.

In the compounds of the formulae VI1 to VI13, the radicals

Preferably +.>

Wherein L is identical or different on each occurrence, has one of the meanings given above or below, and is preferably F, cl, CN, NO ₂ 、CH ₃ 、C ₂ H ₅ 、C(CH ₃ ) ₃ 、CH(CH ₃ ) ₂ 、CH ₂ CH(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 Or P-Sp-, very preferably F, cl, CN, CH ₃ 、C ₂ H ₅ 、OCH ₃ 、COCH ₃ 、OCF ₃ More preferably F, cl, CH ₃ 、OCH ₃ 、COCH ₃ 、CF ₃ Or OCF (optical clear) ₃ In particular F or CH ₃ 。

In a preferred embodiment of the invention, component a of the LC medium comprises one or more third polymerisable compounds, wherein the two polymerisable groups are different from each other. Preferably, in this preferred embodiment, component A of the LC medium comprises one or more compounds of the formula VI or of the sub-formulae VI1 to VI13, where P ¹ P ² Different from each other. Preferably, in these compounds of the formulae VI and VI1 to VI13, P ¹ P ² One of which is vinyloxy and the other is acrylate, methacrylate or ethyl acrylate, most preferably methacrylate.

Other preferred compounds of formulae VI1 to VI13 are those wherein Sp ¹ Sp and Sp ² Those that are single bonds.

Other preferred compounds of formulae VI1 to VI13 are those wherein Sp ¹ Sp and Sp ² One of which is a single bond and the other is not.

Other preferred compounds of the formulae VI1 to VI13 are those in which the group Sp is not a single bond ¹ Sp and Sp ³ Is- (CH) ₂ ) _s1 Those of-X', wherein s1 isAn integer from 1 to 6, preferably 2, 3, 4 or 5, and X' is a bond to a benzene ring and is-O-; -O-CO-, -CO-O, -O-CO-O-, or a single bond.

Very preferably, the compound of formula VI is selected from the group consisting of the following subformulae:

the concentration of the first polymerizable compound in the LC medium, especially those of formula II or IIA, is preferably 1% to 30%, very preferably 1% to 25%, most preferably 5% to 25%.

The concentration of the second polymerizable compound in the LC medium, especially those of formula II or III, is preferably 0.5% to 30%, very preferably 1% to 20%, most preferably 2% to 15%.

The concentration of the third polymerizable compound in the LC medium, especially those of formula IV, is preferably 1% to 30%, very preferably 1% to 25%, most preferably 5% to 25%.

The concentration of the fourth polymerizable compound in the LC medium, especially those of formula V, is preferably 1% to 30%, very preferably 1% to 25%, most preferably 5% to 25%.

The concentration of the fourth polymerizable compound of formula V having one maleimide group in the LC medium is preferably 1% to 30%, very preferably 1% to 25%, most preferably 5% to 25%. The concentration of the fourth polymerizable compound of formula V having two maleimide groups in the LC medium is preferably 0.1% to 30%, very preferably 0.1% to 10%, most preferably 0.1% to 5%.

The concentration of the fifth polymerizable compound in the LC medium, especially those of formula VI, is preferably 0.05% to 5%, very preferably 0.1% to 3%, most preferably 0.2% to 2%.

The total concentration of the first, second, third, fourth and fifth polymerizable compounds in the LC medium, especially those of formulae II, IIA, III, IV, V and VI, is preferably from 1 to 40 wt-%, very preferably from 5 to 30 wt-%.

In a first preferred embodiment of the invention, the total concentration of the first, second, third, fourth and fifth polymerizable compounds in the LC medium, in particular those having the formulae II, IIA, III, IV, V and VI, is from 10% to 40% by weight.

In a second preferred embodiment of the invention, the total concentration of the first, second, third, fourth and fifth polymerizable compounds in the LC medium, in particular those of the formulae II, IIA, III, IV, V and VI, is from 5% to 10% by weight.

In a third preferred embodiment of the invention, the total concentration of the first, second, third, fourth and fifth polymerizable compounds in the LC medium, in particular those of the formulae II, IIA, III, IV, V and VI, is from 1% to 5% by weight.

The total concentration of the first, second and fourth polymerizable compounds having (exactly) one polymerizable group or compounds of the formulae II, IIA and V in the LC medium is preferably from 5 to 30% by weight.

The total concentration of the second, third, fourth and fifth polymerizable compounds having (exactly) two polymerizable groups or compounds of the formulae III, IV, V and VI in the LC medium is preferably from 0.1 to 15% by weight, very preferably from 0.5 to 10% by weight.

Particularly preferred are LC media in which the polymerisable component a comprises one, two or three first polymerisable compounds, preferably of formula II or IIA, one, two or three second polymerisable compounds, preferably of formula III, and optionally one, two or three third or fourth polymerisable compounds, preferably of formula IV or V.

Preferably, the polymerizable component a contains one or more polymerization initiators capable of initiating free radical polymerization. Suitable types and amounts of initiators are known to the person skilled in the art and are described in the literature. Preferably, the initiator is a photoinitiator. Suitable photoinitiators for free-radical polymerization are, for example, commercially available Or->(Ciba AG)。

Preferably, the concentration of the polymerization initiator in the LC medium is 0.001 to 10 wt%, very preferably 0.01 to 5 wt%, most preferably 0.01 to 2 wt%.

Further preferably, the polymerizable component a contains one or more photosensitizers. Examples of suitable and preferred photosensitizers include Isopropyl Thioxanthone (ITX) and thioxanthone.

Preferably, the concentration of the photosensitizer in the LC medium is from 0.001 wt% to 10 wt%, very preferably from 0.001 wt% to 5 wt%, most preferably from 0.001 wt% to 2 wt%.

It is further preferred that the LC medium comprises one or more stabilizers to prevent undesired spontaneous polymerization of the polymerizable monomers during e.g. storage or transportation. Suitable types and amounts of stabilizers are known to the person skilled in the art and are described in the literature. Especially suitable are, for example, fromCommercially available stabilizers of the series (Ciba AG), e.g.1076。

Preferably, the total concentration of stabilizers in the LC medium is 0.001 to 3 wt%, very preferably 0.01 to 1 wt%, most preferably 0.05 to 0.5 wt%.

Another preferred embodiment of the invention relates to LC media comprising one or more self-aligning (SA) additives in addition to components a and B as set forth above. Such LC media are suitable for use in so-called "self-aligned" or self-aligning "(SA) mode displays.

Thus, it is observed that the adverse interactions of the polyimide alignment layer with certain compounds of the LC medium generally result in a decrease in the resistance of the LC display.

In such SA displays, the alignment layer, which is typically present in LCDs to ensure a specific initial alignment of LC molecules, is omitted on one or both substrates. Instead, self-aligning agents are added to the LC medium to induce the desired alignment (e.g. homeotropic or planar alignment) in situ by a self-assembly mechanism.

Suitable self-aligning additives are, for example, compounds having an organic core group and one or more polar anchoring groups attached thereto, which anchoring groups are capable of interacting with the substrate surface, such that the additive on the substrate surface is aligned and also induces the desired alignment in the LC molecules.

Suitable self-aligning additives to induce homeotropic alignment are disclosed, for example, in US 2013/0182202 A1, US 2014/0838581 A1, US 2015/0166890 A1 and US 2015/0252265 A1.

Preferred SA additives are selected from compounds comprising mesogenic groups and linear or branched alkyl side chains terminated with one or more polar anchoring groups selected from hydroxyl, carboxyl, amino or thiol groups. Other preferred SA additives contain one or more polymerizable groups optionally linked to the mesogenic groups via spacer groups. These polymerizable SA additives can polymerize in the LC medium under conditions similar to RM's suitable for use in PSA processes.

The LC medium preferably contains one or more SA additives at a concentration of 0.1% to 2.5%.

The SA mode may also be used in combination with the PSA mode. Thus, in addition to components a and B as set forth above and below, another preferred LC medium of the present invention also contains a second polymerizable component C) comprising one or more polymerizable compounds comprising one or more polymerizable groups capable of free radical polymerization, preferably selected from formula R or a subfraction thereof, and additionally contains one or more self-aligning additives as set forth above and below.

In addition to the polymerizable component a set forth above, the LC medium of the present invention also includes an LC component B or LC host mixture comprising one or more, preferably two or more LC compounds selected from the group of non-polymerizable low molecular weight compounds. These LC compounds are selected such that they are stable and/or non-reactive to the polymerization reaction under conditions suitable for polymerizing the polymerizable compounds.

Preferred are LC media in which the LC component B or LC host mixture has a nematic LC phase and preferably no chiral liquid crystal phase. The LC component B or LC host mixture is preferably a nematic LC mixture.

In addition, preference is given to LC media in which the achiral polymerizable compounds and the compounds of components a and/or B are exclusively selected from the group consisting of achiral compounds.

Preferably, the proportion of LC component B in the LC medium is 70 to 95 wt%.

The LC medium and LC host mixture of the present invention preferably have a nematic phase range of > 80K, very preferably > 100K and a rotational viscosity of preferably < 250 mPa-s, very preferably < 200 mPa-s at 20 ℃.

The birefringence Δn of the LC medium and LC host mixture according to the invention is preferably from 0.07 to 0.15, particularly preferably from 0.08 to 0.15.

In a first preferred embodiment of the invention, the LC medium contains a component B or LC host mixture with positive dielectric anisotropy Δε.

Such LC media are particularly suitable for TN, OCB-, positive-VA-, IPS-or FFS-displays or related modes using LC materials with Δε > 0.

According to this first preferred embodiment, the LC medium and LC host mixture preferably have a positive dielectric anisotropy Δε of +2 to +30, particularly preferably +3 to +20, at 20 ℃ and 1 kHz.

Particularly preferred is the LC medium of this first preferred embodiment, wherein the liquid crystal component B or LC host mixture comprises one or more compounds selected from the group consisting of formulae a and B:

Each independently of the other and at each occurrence the same or different is

R ²¹ 、R ³¹ Each independently of the others is an alkyl, alkoxy, oxaalkyl or alkoxyalkyl group having from 1 to 9C atoms or an alkenyl or alkenyloxy group having from 2 to 9C atoms, all of which are optionally fluorinated,

X ⁰ is F, cl, an alkyl or alkoxy halide having 1 to 6C atoms or an alkenyl or alkenyloxy halide having 2 to 6C atoms,

Z ³¹ is-CH ₂ CH ₂ -、-CF ₂ CF ₂ -, -COO-, trans-ch=ch-, trans-cf=cf-, -CH ₂ O-or a single bond, preferably-CH ₂ CH ₂ -, -COO-, trans-CH=CH-or a single bond, particularly preferred are-COO-, trans-CH=CH-, or a single bond,

L ²¹ 、L ²² 、L ³¹ 、L ³² each independently of the other is H or F,

g is 0, 1, 2 or 3.

In the compounds of the formulae A and B, X ⁰ Preferably F, cl, CF ₃ 、CHF ₂ 、OCF ₃ 、OCHF ₂ 、OCFHCF ₃ 、OCFHCHF ₂ 、OCFHCHF ₂ 、OCF ₂ CH ₃ 、OCF ₂ CHF ₂ 、OCF ₂ CHF ₂ 、OCF ₂ CF ₂ CHF ₂ 、OCF ₂ CF ₂ CHF ₂ 、OCFHCF ₂ CF ₃ 、OCFHCF ₂ CHF ₂ 、OCF ₂ CF ₂ CF ₃ 、OCF ₂ CF ₂ CClF ₂ 、OCClFCF ₂ CF ₃ Or ch=cf ₂ Very preferably F or OCF ₃ Most preferred is F.

In the compounds of the formulae A and B, R ²¹ R is R ³¹ Preferably selected from the group consisting of linear alkyl or alkoxy groups having 1, 2, 3, 4, 5 or 6C atoms and linear alkenyl groups having 2, 3, 4, 5, 6 or 7C atoms.

In the compounds of the formulae A and B, g is preferably 1 or 2.

In the compounds of formula B, Z ³¹ COO, trans-ch=ch or a single bond is preferred, and COO or a single bond is very preferred.

Preferably, component B of the LC medium comprises one or more compounds of formula a selected from the group consisting of:

Wherein A is ²¹ 、R ²¹ 、X ⁰ 、L ²¹ L and L ²² Has the meaning given in formula A, L ²³ L and L ²⁴ Each independently of the other is H or F, and X ⁰ Preferably F. Particularly preferred are compounds of formulae A1 and A2.

Particularly preferred compounds of formula A1 are selected from the group consisting of the following subformulae:

/>

wherein R is ²¹ 、X ⁰ 、L ²¹ L and L ²² Has the meaning given in formula A1, L ²³ 、L ²⁴ 、L ²⁵ L and L ²⁶ Each independently of the other is H or F, and X ⁰ Preferably F.

Very particularly preferred compounds of formula A1 are selected from the group consisting of the following subformulae:

/>

wherein R is ²¹ As defined in formula A1.

Particularly preferred compounds of formula A2 are selected from the group consisting of the following subformulae:

/>

wherein R is ²¹ 、X ⁰ 、L ²¹ L and L ²² Has the meaning given in formula A2, L ²³ 、L ²⁴ 、L ²⁵ L and L ²⁶ Each independently of the other is H or F, and X ⁰ Preferably F.

Very particularly preferred compounds of formula A2 are selected from the group consisting of the following subformulae:

/>

wherein R is ²¹ X is X ⁰ Is as defined in formula A2.

Particularly preferred compounds of formula A3 are selected from the group consisting of the following subformulae:

/>

wherein R is ²¹ 、X ⁰ 、L ²¹ L and L ²² Has the meaning given in formula A3, and X ⁰ Preferably F.

Particularly preferred compounds of formula A4 are selected from the group consisting of the following subformulae:

wherein R is ²¹ Is as defined in formula A4.

Preferably, component B of the LC medium comprises one or more compounds of formula B selected from the group consisting of:

Wherein g, A ³¹ 、A ³² 、R ³¹ 、X ⁰ 、L ³¹ L and L ³² Has the meaning given in formula B, and X ⁰ Preferably F. Particularly preferred are compounds of the formulae B1 and B2.

Particularly preferred compounds of formula B1 are selected from the group consisting of the following subformulae:

wherein R is ³¹ 、X ⁰ 、L ³¹ L and L ³² Has the meaning given in formula B1, and X ⁰ Preferably F.

Very particularly preferred compounds of the formula B1a are selected from the group consisting of the following subformulae:

/>

wherein R is ³¹ Is as defined in formula B1.

Very particularly preferred compounds of the formula B1B are selected from the group consisting of the following subformulae:

wherein R is ³¹ Is as defined in formula B1.

Particularly preferred compounds of formula B2 are selected from the group consisting of the following subformulae:

/>

wherein R is ³¹ 、X ⁰ 、L ³¹ L and L ³² Has the meaning given in formula B2, L ³³ 、L ³⁴ 、L ³⁵ L and L ³⁶ Each independently of the other is H or F, and X ⁰ Preferably F.

Very particularly preferred compounds of the formula B2 are selected from the group consisting of the following subformulae:

/>

wherein R is ³¹ Is as defined in formula B2.

Very particularly preferred compounds of the formula B2B are selected from the group consisting of the following subformulae:

wherein R is ³¹ Is as defined in formula B2.

Very particularly preferred compounds of the formula B2c are selected from the group consisting of the following subformulae:

wherein R is ³¹ Is as defined in formula B2.

Very particularly preferred compounds of the formulae B2d and B2e are selected from the group consisting of the following subformulae:

wherein R is ³¹ Is as defined in formula B2.

Very particularly preferred compounds of the formula B2f are selected from the group consisting of the following subformulae:

wherein R is ³¹ Is as defined in formula B2.

Very particularly preferred compounds of the formula B2g are selected from the group consisting of the following subformulae:

wherein R is ³¹ Is as defined in formula B2.

Very particularly preferred compounds of the formula B2h are selected from the group consisting of the following subformulae:

wherein R is ³¹ Is as defined in formula B2.

Very particularly preferred compounds of the formula B2i are selected from the group consisting of the following subformulae:

wherein R is ³¹ Is as defined in formula B2.

Very particularly preferred compounds of the formula B2k are selected from the group consisting of the following subformulae:

wherein R is ³¹ Is as defined in formula B2.

Very particularly preferred compounds of the formula B2l are selected from the group consisting of the following subformulae:

wherein R is ³¹ Is as defined in formula B2.

Alternatively or additionally, the compounds of formula B1 and/or B2 component B of the LC medium may also comprise one or more compounds of formula B3 as defined above.

Particularly preferred compounds of formula B3 are selected from the group consisting of the following subformulae:

wherein R is ³¹ Is as defined in formula B3.

Preferably, component B of the LC medium comprises, in addition to the compounds of formula A and/or B, one or more compounds of formula C

Wherein the individual radicals have the following meanings:

Each independently of the other

And is identical or different at each occurrence

R ⁴¹ 、R ⁴² Each independently of the others is an alkyl group having 1 to 9C atoms, an alkoxy group,Oxaalkyl or alkoxyalkyl or alkenyl or alkenyloxy having 2 to 9C atoms, all of which are optionally fluorinated,

Z ⁴¹ 、Z ⁴² each independently of the other is-CH ₂ CH ₂ -, -COO-, trans-ch=ch-, trans-cf=cf-, -CH ₂ O-、-CF ₂ O-, -C.ident.C-or a single bond, preferably a single bond,

h is 0, 1, 2 or 3.

In the compounds of formula C, R ⁴¹ R is R ⁴² Preferably selected from the group consisting of linear alkyl or alkoxy groups having 1, 2, 3, 4, 5 or 6C atoms and linear alkenyl groups having 2, 3, 4, 5, 6 or 7C atoms.

In the compounds of the formula C, h is preferably 0, 1 or 2.

In the compounds of the formula C, Z ⁴¹ Z is as follows ⁴² Preferably selected from COO, trans-ch=ch and a single bond, very preferably COO and a single bond.

Particularly preferred compounds of formula C are selected from the group consisting of the following subformulae:

/>

wherein R is ⁴¹ R is R ⁴² Having the meanings given in formula C and preferably each independently of the other representing an alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy group having 1 to 7C atoms or an alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl group having 2 to 7C atoms.

In a further preferred embodiment of the invention, component B of the LC medium comprises, in addition to the compounds of the formulae A and/or B, one or more compounds of the formula D

/>

Wherein A is ⁴¹ 、A ⁴² 、Z ⁴¹ 、Z ⁴² 、R ⁴¹ 、R ⁴² And h has the meaning given in formula C or one of the preferred meanings given above.

Preferred compounds of formula D are selected from the group consisting of the following subformulae:

wherein R is ⁴¹ R is R ⁴² Has the meaning given in formula D and R ⁴¹ Preferably represents alkyl, and R in formula D1 ⁴² Preferably represents alkenyl, particularly preferably- (CH) ₂ ) ₂ -CH＝CH-CH ₃ And R in formula D2 ⁴² Preferably alkyl, - (CH) ₂ ) ₂ -CH＝CH ₂ Or- (CH) ₂ ) ₂ -CH＝CH-CH ₃ 。

In a further preferred embodiment of the invention, component B of the LC medium comprises, in addition to the compounds of the formulae A and/or B, one or more alkenyl-containing compounds of the formula E

Wherein the individual radicals have the following meanings, identically or differently, independently of one another, in each case:

is->

Is->

R ^A1 Is alkenyl having 2 to 9C atoms, or if at least one of ring X, Y and Z represents cyclohexenyl, it also has R ^A2 In one of the meanings of (a),

R ^A2 is an alkyl radical having 1 to 12C atoms, in addition one or two non-adjacent CH ₂ The groups may be replaced by the following groups in such a way that the O atoms are not directly connected to each other: -O-, -ch=ch-, -CO-, -OCO-or-COO-,

x is 1 or 2.

R ^A2 Preference is given to straight-chain alkyl or alkoxy groups having 1 to 8C atoms or straight-chain alkenyl groups having 2 to 7C atoms.

Preferred compounds of formula E are selected from the following subformulae:

/>

Wherein alkyl and alkyl each independently represent a linear alkyl group having 1 to 6C atoms, and alkyl each independently represent a linear alkenyl group having 2 to 7C atoms. alkinyl and alkinyl preferably represent CH ₂ ＝CH-、CH ₂ ＝CHCH ₂ CH ₂ -、CH ₃ -CH＝CH-、CH ₃ -CH ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₃ -ch=ch-or CH ₃ -CH＝CH-(CH ₂ ) ₂ -。

Highly preferred compounds of formula E are selected from the following subformulae:

/>

wherein m represents 1, 2, 3, 4, 5 or 6,i represents 0, 1, 2 or 3, and R ^b1 Representation H, CH ₃ Or C ₂ H ₅ 。

Very particularly preferred compounds of the formula E are selected from the following subformulae:

most preferred are compounds of formulae E1a2, E1a5, E3a1 and E6a 1.

In a further preferred embodiment of the invention, component B of the LC medium comprises, in addition to the compounds of the formulae A and/or B, one or more compounds of the formula F

representation of

R ²¹ 、R ³¹ Each independently of the others is an alkyl, alkoxy, oxaalkyl or alkoxyalkyl radical having from 1 to 9C atoms or an alkenyl or alkenyloxy radical having from 2 to 9C atoms, all of which areOptionally a fluorinated group of the monomers is present,

Z ²¹ is-CH ₂ CH ₂ -、-CF ₂ CF ₂ -, -COO-, trans-ch=ch-, trans-cf=cf-, -CH ₂ O-、-CF ₂ O-, -C.ident.C-or a single bond, preferably-CF ₂ O-，

L ²¹ 、L ²² 、L ²³ 、L ²⁴ Each independently of the other is H or F,

g is 0, 1, 2 or 3.

Particularly preferred compounds of formula F are selected from the group consisting of:

wherein R is ²¹ 、X ⁰ 、L ²¹ L and L ²² Having the meaning given in formula F, L ²⁵ L and L ²⁶ Each independently of the other is H or F, and X ⁰ Preferably F.

Very particularly preferred compounds of the formulae F1 to F3 are selected from the group consisting of the following subformulae:

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wherein R is ²¹ Is as defined in formula F1.

In a further preferred embodiment of the invention, component B of the LC medium comprises, in addition to the compounds of the formulae A and/or B, one or more compounds of the formula G which contain cyano groups.

Wherein the individual radicals have the following meanings:

each independently of the other

And is identical or different at each occurrence

R ⁵¹ 、R ⁵² Each independently of the others is an alkyl, alkoxy, oxaalkyl or alkoxyalkyl group having from 1 to 9C atoms or an alkenyl or alkenyloxy group having from 2 to 9C atoms, all of which are optionally fluorinated,

Z ⁵¹ 、Z ⁴² is-CH ₂ CH ₂ -, -COO-, trans-ch=ch-, trans-cf=cf-, -CH ₂ O-、-CF ₂ O-, -C.ident.C-or a single bond, preferably a single bond,

L ⁵¹ 、L ⁵² each independently of the other is H or F,

i is 0, 1, 2 or 3.

Preferred compounds of formula G are selected from the following subformulae

/>

Wherein R is ⁵¹ Is as defined in G and L ¹ L and L ² Each independently of the other is H or F.

Very particular preference is given to compounds of the formulae G1, G2 and G5.

Preferred compounds of the formulae G1 to G9 are those in which L ⁵¹ L and L ⁵² Those of F.

Other preferred compounds of the formulae G1 to G7 are those in which L ⁵¹ Is F and L ⁵² Are those of H.

Highly preferred compounds of formula G are selected from the group consisting of the following subformulae:

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wherein R is ⁵¹ Is as defined in formula G.

In the compounds of the formulae G, G to G7 and their sub-formulae, R ⁵¹ Particularly preferred are alkyl or alkoxy groups having 1 to 8 carbon atoms or alkenyl groups having 2 to 7 carbon atoms.

The concentration of the compounds of formulae a and B in the LC host mixture is preferably from 2 to 60%, very preferably from 3 to 45%, most preferably from 4 to 35%.

The concentration of the compounds of formulae C and D in the LC host mixture is preferably from 2 to 70%, very preferably from 5 to 65%, most preferably from 10 to 60%.

The concentration of the compound of formula E in the LC host mixture is preferably 5 to 50%, very preferably 5 to 35%.

The concentration of the compound of formula F in the LC host mixture is preferably from 2 to 30%, very preferably from 5 to 20%.

Other preferred embodiments of the invention are listed below, including any combination thereof.

a) The LC host mixture comprises one or more compounds of formula a and/or B having a high positive dielectric anisotropy, preferably delta epsilon > 15.

b) The LC host mixture comprises one or more compounds selected from the group consisting of: a1A2, A1B1, A1d1, A1F1, A2A1, A2h1, A2l2, A2k1, B2h3, B2l1, F1a. The proportion of these compounds in the LC host mixture is preferably from 4 to 40%, very preferably from 5 to 35%.

c) The LC host mixture comprises one or more compounds selected from the group consisting of: c3, C4, C5, C9 and D2. The proportion of these compounds in the LC host mixture is preferably from 8 to 70%, very preferably from 10 to 60%.

d) The LC host mixture comprises one or more compounds selected from the group consisting of: g1, G2 and G5, preferably G1a, G2a and G5a. The proportion of these compounds in the LC host mixture is preferably from 4 to 40%, very preferably from 5 to 35%.

e) The LC host mixture comprises one or more compounds selected from the group consisting of: e1, E3 and E6, preferably E1a, E3a and E6a, very preferably E1a2, E1a5, E3a1 and E6a1. The proportion of these compounds in the LC host mixture is preferably from 5 to 60%, very preferably from 10 to 50%.

In a second preferred embodiment of the invention, the LC medium contains a component B or LC host mixture with a negative dielectric anisotropy Δε.

Such LC media are particularly suitable for VA, IPS and UB-FFS displays or related modes using LC materials with Δε < 0.

The LC medium and LC host mixture of this second preferred embodiment preferably have a negative dielectric anisotropy Δε of-0.5 to-10, very preferably-2.5 to-7.5, at 20 ℃ and 1 kHz.

Particularly preferred embodiments of the LC medium of this second preferred embodiment are those of the following articles section a) -z 2):

a) LC medium wherein component B or LC host mixture comprises one or more compounds selected from formulas CY and PY:

wherein the method comprises the steps of

a represents a group consisting of 1 and 2,

b represents 0 or 1, and the number of the groups is,

representation->

R ¹ R is R ² Each independently of the others represents an alkyl radical having 1 to 12C atoms, in addition to one or two non-adjacent CH ₂ The radicals may be bound to one another via-O-, in such a way that the O atoms are not directly connected to one another-CH=CH-, -CO-, -OCO-, or-COO-, preferably alkyl or alkoxy having 1 to 6C atoms,

Z ^x z is as follows ^y Each independently of the other represents-CH ₂ CH ₂ -、-CH＝CH-、-CF ₂ O-、-OCF ₂ -、-CH ₂ O-、-OCH ₂ -、-CO-O-、-O-CO-、-C ₂ F ₄ -、-CF＝CF-、-CH＝CH-CH ₂ O-or a single bond, preferably a single bond,

L ^1-4 each independently of the other represents F, cl, OCF ₃ 、CF ₃ 、CH ₃ 、CH ₂ F、CHF ₂ 。

Preferably L ¹ L and L ² Both represent F, or L ¹ L and L ² One of them represents F and the other represents Cl, or L ³ L and L ⁴ Both represent F, or L ³ L and L ⁴ One of them represents F and the other represents Cl.

The compound of formula CY is preferably selected from the group consisting of the following subformulae:

/>

wherein a represents 1 or 2, alkyl and alkyl each independently of the other represent a linear alkyl group having 1 to 6C atoms, and alkyl represents a linear alkenyl group having 2 to 6C atoms, and (O) represents an oxygen atom or a single bond. The alkinyl preferably represents CH ₂ ＝CH-、CH ₂ ＝CHCH ₂ CH ₂ -、CH ₃ -CH＝CH-、CH ₃ -CH ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₃ -ch=ch-or CH ₃ -CH＝CH-(CH ₂ ) ₂ -。

Particularly preferred are compounds selected from the formulae CY2, CY8, CY10 and CY 16.

The compound of formula PY is preferably selected from the group consisting of the following subformulae:

/>

wherein alkyl and alkyl each independently of the other represent a linear alkyl group having 1 to 6C atoms, and alkyl represents a group having 2 to 6C atomsA linear alkenyl group of a child, and (O) represents an oxygen atom or a single bond. The alkinyl preferably represents CH ₂ ＝CH-、CH ₂ ＝CHCH ₂ CH ₂ -、CH ₃ -CH＝CH-、CH ₃ -CH ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₃ -ch=ch-or CH ₃ -CH＝CH-(CH ₂ ) ₂ -。

Particularly preferred are compounds selected from the group consisting of the formulae PY2, PY8, PY10 and PY 16.

Preferably, the concentration of the compounds of the formulae CY and PY and their subformulae in the LC medium is from 10 to 70% by weight, very preferably from 15 to 50% by weight.

Preferably, the concentration of the compounds of formula CY and its subformulae in the LC medium is from 2 to 40% by weight, very preferably from 3 to 30% by weight.

Preferably, the concentration of the compounds of formula PY and its subformulae in the LC medium is from 2 to 50% by weight, very preferably from 3 to 40% by weight.

b) An LC medium in which component B or LC host mixture comprises one or more mesogenic or LC compounds (hereinafter also referred to as "alkenyl compounds") comprising alkenyl groups, wherein the alkenyl groups are stable to polymerization under the conditions used for polymerization of the polymerizable compounds contained in the LC medium.

Preferably, component B or the LC host mixture comprises one or more alkenyl compounds selected from the group consisting of the formulae AN and AY

Wherein the individual radicals are identical or different on each occurrence and each have, independently of one another, the following meanings:

is->

Is->

Z ^x is-CH ₂ CH ₂ -、-CH＝CH-、-CF ₂ O-、-OCF ₂ -、-CH ₂ O-、-OCH ₂ -、-CO-O-、-O-CO-、-C ₂ F ₄ -、-CF＝CF-、-CH＝CH-CH ₂ O-or a single bond, preferably a single bond,

L ^1-4 is H, F, cl, OCF ₃ 、CF ₃ 、CH ₃ 、CH ₂ F or CHF ₂ Preferably H, F or Cl,

x is either 1 or 2 and is preferably chosen,

z is 0 or 1.

Preferred compounds of formula AN and AY are those wherein R ^A2 Selected from the group consisting of ethenyl, propenyl, butenyl, pentenyl, hexenyl and heptenyl.

In a preferred embodiment, component B or LC host mixture comprises one or more compounds of formula AN selected from the following subformulae:

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Preferably, component B or LC host mixture comprises one or more compounds selected from the group consisting of formulae AN1, AN2, AN3 and AN6, very preferably one or more compounds of formula AN 1.

In another preferred embodiment, component B or LC host mixture comprises one or more compounds of formula AN selected from the following subformulae:

In another preferred embodiment, component B or LC host mixture comprises one or more compounds selected from the following subformulae:

/>

most preferred are compounds of formulae AN1a2 and AN1a 5.

In another preferred embodiment, component B or LC host mixture comprises one or more compounds of formula AY selected from the following subformulae:

/>

wherein alkyl and alkyl each independently represent a linear alkyl group having 1 to 6C atoms, "(O)" represents an oxygen atom or a single bond, and alkyl each independently represent a linear alkenyl group having 2 to 7C atoms. alkinyl and alkinyl preferably represent CH ₂ ＝CH-、CH ₂ ＝CHCH ₂ CH ₂ -、CH ₃ -CH＝CH-、CH ₃ -CH ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₃ -ch=ch-or CH ₃ -CH＝CH-(CH ₂ ) ₂ -。

/>

wherein m and n each independently of the other represent 1, 2, 3, 4, 5 or 6, and alkinyl represents CH ₂ ＝CH-、CH ₂ ＝CHCH ₂ CH ₂ -、CH ₃ -CH＝CH-、CH ₃ -CH ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₃ -ch=ch-or CH ₃ -CH＝CH-(CH ₂ ) ₂ -。

Preferably, the proportion of compounds of the formulae AN and AY in the LC medium is from 2 to 70% by weight, very preferably from 5 to 60% by weight, most preferably from 10 to 50% by weight.

Preferably, the LC medium or LC host mixture contains 1 to 5, preferably 1, 2 or 3 compounds selected from the formulae AN and AY.

In another preferred embodiment of the invention, the LC medium comprises one or more compounds of formula AY14, very preferably of formula AY14 a. The proportion of the compounds of the formula AY14 or AY14a in the LC medium is preferably from 3 to 20% by weight.

The addition of alkenyl compounds of the formula AN and/or AY enables the viscosity and response time of the LC medium to be reduced.

c) An LC medium wherein component B or LC host mixture comprises one or more compounds having the formula:

wherein the individual radicals have the following meanings:

representation->

Representation->

R ³ R is R ⁴ Each independently of the others represents an alkyl radical having 1 to 12C atoms, in addition to one or two non-adjacent CH ₂ The radicals may be bound to one another via-O-, in such a way that the O atoms are not directly connected to one another-ch=ch-, -CO-, -O-CO-or-CO-O-substitution,

Z ^y represents-CH ₂ CH ₂ -、-CH＝CH-、-CF ₂ O-、-OCF ₂ -、-CH ₂ O-、-OCH ₂ -、-CO-O-、-O-CO-、-C ₂ F ₄ -、-CF＝CF-、-CH＝CH-CH ₂ O-or a single bond, preferably a single bond.

The compound of formula ZK is preferably selected from the group consisting of the following subformulae:

wherein alkyl and alkyl each independently represent a linear alkyl group having 1 to 6C atoms, and alkyl represents a linear alkenyl group having 2 to 6C atoms. The alkinyl preferably represents CH ₂ ＝CH-、CH ₂ ＝CHCH ₂ CH ₂ -、CH ₃ -CH＝CH-、CH ₃ -CH ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₃ -ch=ch-or CH ₃ -CH＝CH-(CH ₂ ) ₂ -。

Particularly preferred are compounds of formula ZK 1.

Particularly preferred compounds of formula ZK are selected from the following subformulae:

wherein propyl, butyl and pentyl are straight chain groups.

Most preferred are compounds of formula ZK1 a.

d) LC medium, wherein component B or LC host mixture additionally comprises one or more compounds having the formula:

wherein each group, identically or differently, at each occurrence, has the following meaning:

R ⁵ r is R ⁶ Each independently of the others represents an alkyl radical having 1 to 12C atoms, in addition to one or two non-adjacent CH ₂ The groups may be replaced by the following groups in such a way that the O atoms are not directly connected to each other: -O-, -CH=CH-, -CO-, -OCO-, or-COO-, preferably alkyl or alkoxy having 1 to 6C atoms,

representation->

Representation->

e represents 1 or 2.

The compound of formula DK is preferably selected from the group consisting of the following subformulae:

/>

e) LC medium, wherein component B or LC host mixture additionally comprises one or more compounds having the formula:

wherein the individual radicals have the following meanings:

representation->

And at least one ring F is different from Yu Yahuan hexyl,

f represents a group consisting of 1 and 2,

R ¹ r is R ² Each independently of the others represents an alkyl radical having 1 to 12C atoms, in addition to one or two non-adjacent CH ₂ The radicals may be bound to one another via-O-, in such a way that the O atoms are not directly connected to one another-CH=CH-, -CO-, -OCO-, or-COO-,

Z ^x represents-CH ₂ CH ₂ -、-CH＝CH-、-CF ₂ O-、-OCF ₂ -、-CH ₂ O-、-OCH ₂ -、-CO-O-、-O-CO-、-C ₂ F ₄ -、-CF＝CF-、-CH＝CH-CH ₂ O-or a single bond, preferably a single bond,

L ¹ l and L ² Each independently of the other represents F, cl, OCF ₃ 、CF ₃ 、CH ₃ 、CH ₂ F、CHF ₂ 。

Preferably, the group L ¹ L and L ² Both represent F, or a group L ¹ L and L ² One of them represents F and the other represents Cl.

The compound of formula LY is preferably selected from the group consisting of the following subformulae:

/>

wherein R is ¹ With the meaning indicated above, alkyl represents a straight-chain alkyl group having 1 to 6C atoms, (O) represents an oxygen atom or a single bond, and v represents an integer from 1 to 6. R is R ¹ Preferably represents a linear alkyl radical having 1 to 6C atoms or a linear alkenyl radical having 2 to 6C atoms, in particular CH ₃ 、C ₂ H ₅ 、n-C ₃ H ₇ 、n-C ₄ H ₉ 、n-C ₅ H ₁₁ 、CH ₂ ＝CH-、CH ₂ ＝CHCH ₂ CH ₂ -、CH ₃ -CH＝CH-、CH ₃ -CH ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₃ -ch=ch-or CH ₃ -CH＝CH-(CH ₂ ) ₂ -。

f) LC medium, wherein component B or LC host mixture additionally comprises one or more compounds selected from the group consisting of:

Wherein alkyl represents C _1-6 -alkyl, L ^x Represents H or F, and X represents F, cl, OCF ₃ 、OCHF ₂ Or och=cf ₂ . Particularly preferred are compounds of formula GG1 wherein X represents F.

g) LC medium, wherein component B or LC host mixture additionally comprises one or more compounds selected from the group consisting of:

/>

wherein R is ⁵ Having the above for R ¹ One of the indicated meanings, alkyl represents C _1-6 -alkyl, d represents 0 or 1, and z and m each independently of one another represent an integer from 1 to 6. R in these compounds ⁵ Particularly preferably C _1-6 -alkyl or C _1-6 -alkoxy or C _2-6 -alkenyl, d is preferably 1. The LC medium according to the invention preferably comprises one or more compounds of the formula mentioned above in an amount of ≡5 wt%.

h) LC medium, wherein component B or LC host mixture additionally comprises one or more biphenyl compounds selected from the group consisting of the following formulae:

wherein alkyl and alkyl each independently represent a linear alkyl group having 1 to 6C atoms, and alkyl each independently represent a linear alkenyl group having 2 to 6C atoms. alkinyl and alkinyl preferably represent CH ₂ ＝CH-、CH ₂ ＝CHCH ₂ CH ₂ -、CH ₃ -CH＝CH-、CH ₃ -CH ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₃ -ch=ch-or CH ₃ -CH＝CH-(CH ₂ ) ₂ -。

The proportion of biphenyls of the formulae BP1 to BP3 in the LC host mixture is preferably at least 3% by weight, in particular.gtoreq.5% by weight.

Compounds of formula BP2 are particularly preferred.

The compounds of the formulae BP1 to BP3 are preferably selected from the group consisting of the following subformulae:

wherein alkyl represents an alkyl group having 1 to 6 carbon atoms. The medium according to the invention particularly preferably comprises one or more compounds of the formulae BP1a and/or BP2 c.

i) LC medium, wherein component B or LC host mixture additionally comprises one or more biphenyl compounds of the formula:

wherein R is ⁵ R is R ⁶ Each independently of the other is one of the meanings indicated above, and

each independently of the other represent

Wherein L is ⁵ Represents F or Cl, preferably F, and L ⁶ Represents F, cl and OCF ₃ 、CF ₃ 、CH ₃ 、CH ₂ F or CHF ₂ F is preferred.

The compound of formula T is preferably selected from the group consisting of the following subformulae:

/>

wherein R is as followsShows a linear alkyl or alkoxy group having 1-7C atoms, R represents a linear alkenyl group having 2-7C atoms, (O) represents an oxygen atom or a single bond, and m represents an integer of 1 to 6. R preferably represents CH ₂ ＝CH-、CH ₂ ＝CHCH ₂ CH ₂ -、CH ₃ -CH＝CH-、CH ₃ -CH ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₃ -ch=ch-or CH ₃ -CH＝CH-(CH ₂ ) ₂ -。

R preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy or pentoxy.

The LC host mixtures according to the invention preferably comprise the biphenyls of formula T and their preferred subformulae in an amount of 0.5 to 30% by weight, in particular 1 to 20% by weight.

Particularly preferred are compounds of the formulae T1, T2, T3 and T21. In these compounds, R preferably represents alkyl, further alkoxy, each having 1 to 5C atoms.

If the Δn of the mixture is to be greater than or equal to 0.1, then preferably, biphenyl is used in the LC medium according to the invention. Preferred LC media comprise 2-20 wt.% of one or more compounds of formula T-biphenyl, preferably selected from the group of compounds T1 to T22.

k) LC medium, wherein component B or LC host mixture additionally comprises one or more biphenyl compounds selected from the group consisting of the following formulae:

wherein the method comprises the steps of

R ^Q Is an alkyl, alkoxy, oxaalkyl or alkoxyalkyl group having 1 to 9C atoms or an alkenyl or alkenyloxy group having 2 to 9C atoms, all of which are optionally fluorinated,

X ^Q is F, cl, an alkyl or alkoxy halide having 1 to 6C atoms or an alkenyl or alkenyloxy halide having 2 to 6C atoms,

L ^Q1 to L ^Q6 Are independently of each other H or F, and L ^Q1 To L ^Q6 At least one of which is F.

Preferred compounds of formula Q are those wherein R ^Q Represents those having a linear alkyl group of 2 to 6C atoms, very preferably ethyl, n-propyl or n-butyl.

Preferred compounds of formula Q are those wherein L ^Q3 L and L ^Q4 Those of F. Other preferred compounds of formula Q are those wherein L ^Q1 L and L ^Q2 One or both of them and L ^Q3 、L ^Q4 Those of F.

Preferred compounds of formula Q are those wherein X ^Q Represents F or OCF ₃ Those of F are very preferred.

The compounds of formula Q are preferably selected from the following subformulae

Wherein R is ^Q Having one of the meanings of the formula Q or one of its preferred meanings given above and below, and preferably ethyl, n-propyl or n-butyl.

Particularly preferred are compounds of formula Q1, especially wherein R ^Q Are those of n-propyl group.

Preferably, the proportion of the compounds of the formula Q in the LC host mixture is from > 0 to < 5% by weight, very preferably from 0.1 to 2% by weight, most preferably from 0.2 to 1.5% by weight.

Preferably, the LC host mixture contains 1 to 5, preferably 1 or 2 compounds of formula Q.

The addition of the formula Q-biphenyl compound to the LC host mixture enables reduction of ODF inhomogeneities while maintaining high UV absorption, enables rapid and complete polymerization, enables strong and rapid generation of tilt angles, and increases UV stability of the LC medium.

Furthermore, will have a positive dielectric anisotropyThe addition of the compound of formula Q to LC media with negative dielectric anisotropy allows for better control of the dielectric constant ε _|| Epsilon _⊥ And in particular enables a high dielectric constant epsilon to be achieved _|| The value, while keeping the dielectric anisotropy Δε constant, thereby reducing kick-back voltage (kick-back voltage) and reducing image sticking.

l) LC medium, wherein component B or LC host mixture additionally comprises one or more compounds of formula CC:

wherein the method comprises the steps of

R ^C Represents alkyl, alkoxy, oxaalkyl or alkoxyalkyl having from 1 to 9C atoms or alkenyl or alkenyloxy having from 2 to 9C atoms, all of which are optionally fluorinated,

X ^C represents F, cl, an alkyl or alkoxy halide having 1 to 6C atoms or an alkenyl or alkenyloxy halide having 2 to 6C atoms,

L ^C1 、L ^C2 independently of one another, H or F, and L ^C1 L and L ^C2 At least one of which is F.

Preferred compounds of formula CC are those wherein R ^C Represents those having a linear alkyl group of 2 to 6C atoms, very preferably ethyl, n-propyl or n-butyl.

Preferred compounds of formula CC are those wherein L ^C1 L and L ^C2 Those of F.

Preferred compounds of formula CC are those wherein X ^C Represents F or OCF ₃ Those of F are very preferred.

Preferred compounds of formula CC are selected from the following formulas

Wherein R is ^C Having one of the meanings of the formula CC or one of its preferred meanings given above and below, and preferably BA radical, n-propyl or n-butyl, very preferably n-propyl.

Preferably, the proportion of the compound of formula CC in the LC host mixture is from > 0 to < 10% by weight, very preferably from 0.1 to 8% by weight, most preferably from 0.2 to 5% by weight.

Preferably, the LC host mixture contains 1 to 5, preferably 1, 2 or 3 compounds of formula CC.

The addition of a compound of formula CC with positive dielectric anisotropy to LC media with negative dielectric anisotropy allows for better control of the dielectric constant epsilon _|| Epsilon _⊥ And in particular enables a high dielectric constant epsilon to be achieved _|| The value of the dielectric anisotropy Δε is kept constant, thereby reducing kickback voltage and reducing image sticking. Furthermore, the addition of the compound of formula CC enables a reduction in the viscosity and response time of the LC medium.

m) LC medium, wherein component B or LC host mixture additionally comprises one or more compounds selected from the group consisting of:

/>

wherein R is ¹ R is R ² Having the meanings indicated above and preferably each independently of the other representing a linear alkyl group having 1 to 6C atoms or a linear alkenyl group having 2 to 6C atoms.

Preferably the medium comprises one or more compounds selected from the group consisting of formulae O1, O3 and O4.

n) LC media, wherein component B or the LC host mixture additionally comprises one or more compounds of the formula:

Wherein the method comprises the steps of

Representation->

R ⁹ Representation H, CH ₃ 、C ₂ H ₅ Or n-C ₃ H ₇ (F) represents an optional fluoro substituent, and q represents 1, 2 or 3, and R ⁷ With respect to R ¹ One of the indicated meanings.

Particularly preferred compounds of formula FI are selected from the group consisting of the following subformulae:

/>

wherein R is ⁷ Preferably represents a linear alkyl group, and R ⁹ Represents CH ₃ 、C ₂ H ₅ Or n-C ₃ H ₇ . Particularly preferred are compounds of the formulae FI1, FI2 and FI 3.

o) LC medium, wherein component B or LC host mixture additionally comprises one or more compounds selected from the group consisting of:

/>

wherein R is ⁸ With respect to R ¹ Indicated meaning, andalkyl represents a straight chain alkyl group having 1 to 6C atoms.

p) LC medium, wherein component B or LC host mixture additionally comprises one or more compounds containing tetrahydronaphthyl or naphthyl units, for example compounds selected from the group consisting of the following formulae:

/>

wherein the method comprises the steps of

R ¹⁰ R is R ¹¹ Each independently of the others represents an alkyl radical having 1 to 12C atoms, in addition to one or two non-adjacent CH ₂ The groups may be replaced by the following groups in such a way that the O atoms are not directly connected to each other: -O-, -CH=CH-, -CO-, -OCO-, or-COO-, preferably alkyl or alkoxy having 1 to 6C atoms,

and R is ¹⁰ R is R ¹¹ Preferably represents a linear alkyl or alkoxy radical having 1 to 6C atoms or a linear alkenyl radical having 2 to 6C atoms, an

Z ¹ Z is as follows ² Each independently of the other represents-C ₂ H ₄ -、-CH＝CH-、-(CH ₂ ) ₄ -、-(CH ₂ ) ₃ O-、-O(CH ₂ ) ₃ -、-CH＝CH-CH ₂ CH ₂ -、-CH ₂ CH ₂ CH＝CH-、-CH ₂ O-、-OCH ₂ -、-CO-O-、-O-CO-、-C ₂ F ₄ -、-CF＝CF-、-CF＝CH-、-CH＝CF-、-CH ₂ -or a single bond.

q) LC medium, wherein component B or LC host mixture additionally comprises one or more difluorodibenzochromans and/or chromans of the formulae:

wherein the method comprises the steps of

R ¹¹ R is R ¹² Each independently of the other is a compound having the meaning given above for R ¹¹ One of the meanings indicated is that,

ring M is trans-1, 4-cyclohexylene or 1, 4-phenylene,

Z ^m is-C ₂ H ₄ -、-CH ₂ O-、-OCH ₂ -, a part of-CO-O-or-O-CO-,

c is 0, 1 or 2.

Particularly preferred compounds of formula BC, CR and RC are selected from the group consisting of the following subformulae:

/>

wherein alkyl and alkyl each independently represent a linear alkyl group having 1 to 6C atoms, (O) represents an oxygen atom or a single bond, C is 1 or 2, and alkyl each independently represent a linear alkenyl group having 2 to 6C atoms. alkinyl and alkinyl preferably represent CH ₂ ＝CH-、CH ₂ ＝CHCH ₂ CH ₂ -、CH ₃ -CH＝CH-、CH ₃ -CH ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₃ -ch=ch-or CH ₃ -CH＝CH-(CH ₂ ) ₂ -。

Very particular preference is given to LC host mixtures comprising one, two or three compounds of the formula BC-2.

r) LC medium, wherein component B or LC host mixture additionally comprises one or more of the following fluorinated phenanthrenes and/or dibenzofurans of the formulae:

wherein R is ¹¹ R is R ¹² Each independently of the other is a compound having the meaning given above for R ¹¹ One of the indicated meanings, b represents 0 or 1, l represents F, and r represents 1, 2 or 3.

Particularly preferred compounds of formula PH and BF are selected from the group consisting of the following subformulae:

wherein R and R' each independently of the other represent a linear alkyl or alkoxy group having 1 to 7C atoms.

s) LC medium, wherein component B or the LC host mixture additionally comprises one or more mono-cyclic compounds of the formula

Wherein the method comprises the steps of

R ¹ R is R ² Each independently of the others represents an alkyl radical having 1 to 12C atoms, in addition to one or two non-adjacent CH ₂ The radicals may be bound to one another via-O-, in such a way that the O atoms are not directly connected to one another-CH=CH-, -CO-, -OCO-, or-COO-, preferably an alkyl or alkoxy group having 1 to 6C atoms,

Preferably L ¹ L and L ² Both represent F, or a group L ¹ L and L ² One of which represents F and the other represents Cl,

the compound of formula Y is preferably selected from the group consisting of the following subformulae:

/>

wherein, alkyl and Alkyl each independently represent a linear Alkyl group having 1 to 6C atoms, alkoxy represents a linear Alkoxy group having 1 to 6C atoms, and Alkyl and alkinyl each independently represent a linear Alkenyl group having 2 to 6C atoms. Alkenyl and Alkenyl preferably represent CH ₂ ＝CH-、CH ₂ ＝CHCH ₂ CH ₂ -、CH ₃ -CH＝CH-、CH ₃ -CH ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₂ -CH＝CH-、CH ₃ -(CH ₂ ) ₃ -ch=ch-or CH ₃ -CH＝CH-(CH ₂ ) ₂ -。

Particularly preferred compounds of formula Y are selected from the group consisting of the following subformulae:

wherein Alkoxy preferably represents a straight-chain Alkoxy group having 3, 4 or 5C atoms.

t) LC medium which is free of polymerizable compounds containing terminal vinyloxy groups (-O-ch=ch), other than as described above and below ₂ ) Is a compound of (a).

u) LC medium, wherein component B or LC host mixture comprises 1 to 8, preferably 1 to 5 compounds of formula CY1, CY2, PY1 and/or PY 2. The proportion of these compounds in the LC host mixture as a whole is preferably from 5% to 60%, particularly preferably from 10% to 35%. In each case, the content of these individual compounds is preferably from 2% to 20%.

v) LC medium, wherein component B or LC host mixture comprises 1 to 8, preferably 1 to 5 compounds of formula CY9, CY10, PY9 and/or PY 10. The proportion of these compounds in the LC host mixture as a whole is preferably from 5% to 60%, particularly preferably from 10% to 35%. In each case, the content of these individual compounds is preferably from 2% to 20%.

w) LC medium, wherein component B or LC host mixture contains 1 to 10, preferably 1 to 8, compounds of the formula ZK, in particular compounds of the formulae ZK1, ZK2 and/or ZK 6. The proportion of these compounds in the LC host mixture as a whole is preferably 3% to 25%, particularly preferably 5% to 45%. In each case, the content of these individual compounds is preferably from 2% to 20%.

x) LC medium, wherein the proportion of compounds of the formulae CY, PY and ZK in the LC host mixture as a whole is greater than 70%, preferably greater than 80%.

y) LC medium, wherein the LC host mixture contains one or more alkenyl-containing compounds preferably selected from the formulae AN and AY, very preferably selected from the formulae AN1, AN3, AN6 and AY14, most preferably selected from the formulae AN1a, AN3a, AN6a and AY 14. The concentration of these compounds in the LC host mixture is preferably from 2 to 70%, very preferably from 3 to 55%,

z) LC medium, wherein component B or LC host mixture contains one or more, preferably 1 to 5, compounds selected from the formulae PY1-PY8, very preferably of the formula PY 2. The proportion of these compounds in the LC host mixture as a whole is preferably from 1% to 30%, particularly preferably from 2% to 20%. In each case, the content of these individual compounds is preferably from 1% to 20%.

z 1) LC medium, wherein component B or LC host mixture contains one or more, preferably 1, 2 or 3, compounds selected from the formulae T1, T2, T3 and T21, very preferably from the formula T2. The content of these compounds in the LC host mixture as a whole is preferably 1 to 20%.

z 2) LC medium, wherein the LC host mixture contains one or more, preferably 1, 2 or 3 compounds of the formula BF1, and one or more, preferably 1, 2 or 3 compounds selected from the formulae AY14, AY15 and AY16, very preferably from the formula AY 14. The proportion of the compounds of the formulae AY14 to AY16 in the LC host mixture is preferably from 2 to 35%, very preferably from 3 to 30%. The proportion of the compound of the formula BF1 in the LC host mixture is preferably from 0.5 to 20%, very preferably from 1 to 15%. It is further preferred that the LC host mixture of this preferred embodiment contains one or more, preferably 1, 2 or 3 compounds of formula T, preferably selected from the formulae T1, T2 and T3, very preferably selected from the formula T2. The proportion of the compounds of the formula T in the LC host mixture medium is preferably from 0.5 to 15%, very preferably from 1 to 10%.

In the LC medium of the present invention, the use of the LC host mixture together with a polymerizable component comprising a combination of the first, second and third polymerizable compounds as described above gives advantageous properties in LC displays. In particular, one or more of the following advantages may be realized:

the polymerization-induced phase separation of the polymer formed by the first and second polymerizable compounds readily and rapidly forms polymer walls,

forming a polymer wall having a highly defined shape and a constant thickness,

a constant cell gap is provided for the purpose of,

in the case of plastic substrates the high flexibility of the display box,

high resistance of the display cell to mechanical pressure, and low variation of the cell gap under pressure,

good adhesion of the polymer walls to the substrate,

a low number of defects and,

reduced formation of domains with different optoelectronic properties such as response time or contrast,

a high transparency of the material is achieved,

a good contrast ratio is to be achieved,

fast response time.

Display manufacturing methods are known to the person skilled in the art and are described in the literature, for example US6130738 and EP2818534 A1.

The invention also relates to a method of manufacturing an LC display as described above and below, comprising the steps of: providing an LC medium as described above and below into a display and polymerising the polymerisable compounds in a defined area of the display by RAFT polymerisation.

Preferably, the polymerizable compound is photopolymerized by exposure to UV radiation.

It is also preferred that the polymerizable compound is photopolymerised by exposure to UV radiation through a photomask. The UV radiation may be generated by a variety of light sources known to those skilled in the art including, but not limited to, arc lamps, led lamps, laser light sources, or other light sources.

The photomask is preferably designed such that it comprises regions transparent to UV radiation for photopolymerization and regions opaque to UV radiation for photopolymerization, and wherein the transparent regions form a pattern or image corresponding to the desired shape of the polymer wall. Thus, the polymerizable compound polymerizes only in those portions of the display that are covered by the transparent areas of the photomask, thereby forming the polymer walls having the desired shape.

For using a photomask, alternatively, a light source that emits light having a shaped profile may be used. Such a profile may be generated, for example, by interference of two laser beams.

In a preferred embodiment of the invention, the display is subjected to a second UV irradiation step, preferably without the use of a photomask, after the first UV irradiation step as described above. The polymerization of the monomers which are not polymerized or only partially polymerized in the first step can thus be completed. The second UV step may have the same emission spectrum and/or intensity as the first step or different from the first step.

For the application of two separate irradiation steps, the intensity is alternatively varied during UV exposure. Preferably, the intensity increases gradually during UV exposure.

For example, the LC display of the present invention can be manufactured as follows. The polymerisable compounds as described above and below are combined with a suitable LC host mixture. This resulting LC medium can then be introduced into a display by using conventional manufacturing methods. The resulting LC medium may be filled into the cell gap formed by the two substrates using, for example, capillary forces.

Alternatively, the LC medium may be deposited as a layer onto the substrate and another substrate placed on top of the LC layer under vacuum to prevent the introduction of bubbles. The LC medium is in either case located in the cell gap formed by the two substrates, as illustrated in fig. 1 a. These substrates are typically covered by an alignment layer in direct contact with the LC medium. The substrate itself may carry other functional components such as TFTs, black matrices, color filters or the like.

Subsequently, polymerization-induced phase separation is initiated by exposing the LC medium in nematic or isotropic phase to UV radiation with collimated light via a photomask, as illustrated in fig. 1 b. This results in the formation of a polymer wall structure, recovering the LC host, and aligning the LC phase with the alignment layer, as illustrated in fig. 1 c.

This method can advantageously utilize established display manufacturing methods in the industry. Thus, both the display filling method by e.g. drop-in-fill (ODF) and the radiation initiated polymerization step after sealing the display, which is known from e.g. polymer stabilized or PS-type display modes, such as PS-VA, are established techniques in conventional LCD manufacturing.

A preferred LC display of the invention comprises:

a first substrate comprising pixel electrodes defining pixel areas and optionally a first alignment layer arranged on the pixel electrodes, the pixel electrodes being connected to switching elements arranged in each pixel area and optionally comprising a micro slit pattern,

a second substrate comprising a common electrode layer and optionally a second alignment layer, the common electrode layer being disposable over the entire portion of the second substrate facing the first substrate,

an LC layer disposed between the first and second substrates and comprising an LC medium comprising a polymerizable component a and a liquid crystal component B as described above and below, wherein the polymerizable component a is polymerized.

LC displays may include other elements such as color filters, black matrices, passivation layers, optical retardation layers, transistor elements for addressing individual pixels, etc., all of which are well known to those skilled in the art and may not be employed with the inventive skills.

The electrode structure can be designed by a person skilled in the art according to the respective display type. For example, for VA displays, the multi-domain orientation of LC molecules may be induced by providing electrodes with slits and/or bumps or protrusions to create 2, 4 or more different tilted alignment directions.

The first and/or second alignment layers control the alignment direction of LC molecules of the LC layer. For example, in a TN display the alignment layer is selected such that it imparts an orientation direction of the LC molecules parallel to the surface, whereas in a VA display the alignment layer is selected such that it imparts homeotropic alignment of the LC molecules, i.e. an orientation direction perpendicular to the surface. Such an alignment layer may for example comprise polyimide, which may also be rubbed or may be prepared by a photoalignment method.

The substrate may be a glass substrate, for example in the case of a curved display. The use of the LC medium of the present invention in LC displays with glass substrates may provide several advantages. For example, the formation of a polymer wall structure in the LC medium helps to prevent the so-called "coalescing effect", in which pressure applied on the glass substrate causes undesired optical defects. The stabilizing effect of the polymer wall structure also allows further minimizing the panel thickness. Furthermore, in a curved panel with a glass substrate, the polymer wall structure makes a smaller radius of curvature possible.

For flexible LC displays, a plastic substrate is preferably used. These plastic substrates preferably have a low birefringence. Examples are Polycarbonate (PC), polyethersulfone (PES), polycycloolefin (PCO), polyarylate (PAR), polyetheretherketone (PEEK) or Colorless Polyimide (CPI) substrates.

The LC layer with LC medium may be deposited between the substrates of the display by methods conventionally used by display manufacturers, such as the drop-on fill (ODF) method. The polymerisable component of the LC medium is then polymerised by, for example, UV photopolymerization.

In the case of using a polymerizable compound instead of the spacer particles, the display manufacturing method preferably includes the steps of:

in a first step, an LC medium containing an LC host and a monomer precursor is applied to one of the two substrates, preferably by using one of the following deposition methods: drop-on fill, ink-jet printing, spin coating, slot coating, flexography, or equivalent methods. In this case, the substrate may carry color filters, TFT devices, black matrices, polyimide coatings, or other components commonly found on display substrates. The applied LC medium forms a thin, uniform film with the thickness of the target cell gap of the final device.

In a second step, the applied film is subjected to UV radiation with an intensity profile (profile). This distribution is generated, for example, by irradiation via a photomask, lithography, contact lithography, proximity lithography (proximity lithography), projection lithography, using laser interference, direct laser writing, or equivalent methods. Irradiation of the film may be performed from either side of the substrate. In the case of using a photomask, the mask may be placed on the substrate and the LC film is cured by light passing through the substrate, or the mask may be brought into direct close proximity to the LC film and the LC medium cured directly.

In this second step, a polymer wall structure is created that functions as a spacer.

Subsequently, a second substrate, also carrying color filters, TFT devices, black matrices, polyimide coatings or other components typically found on display substrates, is placed on top of the first substrate such that the LC film is between the two substrates.

Further irradiation may now optionally be performed to convert unreacted monomers, create a bond between the two substrates, and/or seal the edges of the display.

The polymerization of the polymerizable compound may be carried out in one step or in two or more steps. The polymerization may also be carried out in a series of several UV irradiation and/or heating or cooling steps. For example, the display manufacturing method may include a first UV irradiation step at room temperature to generate a pretilt angle, and then in a second polymerization step, the compound that has not reacted in the first step is polymerized or crosslinked ("final curing").

After polymerization, the polymerizable compounds react with each other to form a polymer that undergoes macroscopic phase separation from the LC host mixture and forms polymer walls in the LC medium.

Suitable and preferred polymerization methods are, for example, thermal or photopolymerization, preferably photopolymerization, in particular UV-induced photopolymerization, which can be achieved by exposing the polymerizable compound to UV radiation.

Preferably, the LC medium contains one or more polymerization initiators.

The polymerizable compounds of the invention are also suitable for initiator-free polymerization, which is accompanied by numerous advantages, such as lower material costs and in particular less contamination of the LC medium by possible residual amounts of initiator or degradation products thereof. Thus, the polymerization can also be carried out without addition of initiator. In a preferred embodiment, the LC medium contains a polymerization initiator.

The LC medium may also contain one or more stabilizers or initiators to prevent undesired spontaneous polymerization of the RM during, for example, storage or transport. Suitable types and amounts of stabilizers are known to the person skilled in the art and are described in the literature. Especially suitable are, for example, fromCommercially available stabilizers of the series (Ciba AG), e.g. +.>1076. If stabilizers are used, the proportion is preferably from 10 to 500,000ppm, particularly preferably from 50 to 50,000ppm, based on the sum of RM or polymerizable components (component A).

Preferably, the LC medium of the present invention does consist essentially of the polymerizable component a and LC component B (or LC host mixture) as described above and below. However, the LC medium may additionally comprise one or more other components or additives.

The LC medium according to the invention may also comprise other additives known to the person skilled in the art and described in the literature, such as polymerization initiators, inhibitors, stabilizers, sensitizers, surface-active substances or chiral dopants. These additives may be polymerizable or non-polymerizable. The polymerizable additive, the polymerization initiator and the sensitizer are assigned to the polymerizable component or component a. Other non-polymerizable additives are assigned to the non-polymerizable component or component B.

Preferred additives are selected from the list including but not limited to: comonomers, chiral dopants, polymerization initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricants, dispersants, hydrophobing agents, binders, flow improvers, defoamers, deaerators, diluents, reactive diluents, adjuvants, colorants, dyes, pigments, and nanoparticles.

In a preferred embodiment, the LC medium preferably contains one or more chiral dopants in a concentration of 0.01 to 1 wt%, very preferably 0.05 to 0.5 wt%. The chiral dopant is preferably selected from the group consisting of the compounds of the following table B, very preferably from the group consisting of: r-or S-1011, R-or S-2011, R-or S-3011, R-or S-4011, and R-or S-5011.

In another preferred embodiment, the LC medium contains one or more racemates of chiral dopants, which are preferably selected from the chiral dopants mentioned in the previous paragraph.

Furthermore, for example 0 to 15% by weight of polychromatic dyes, other nanoparticles, conductive salts to improve the conductivity, preferably ethyldimethyldodecyl4-hexyloxybenzoic acid ammonium, tetrabutyltetraphenylammonium borate or complex salts of crown ethers (see for example Haller et al mol. Cryst. Liq. Cryst.24,249-258 (1973)), or substances for changing the dielectric anisotropy, viscosity and/or alignment of the nematic phase, can be added to the LC medium. Such substances are described, for example, in DE-A22 09 127, 22 40 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430 and 28 53 728.

LC media which can be used according to the invention are prepared in a manner conventional per se, for example by mixing one or more of the compounds mentioned above with one or more of the polymerizable compounds defined above, and optionally with other liquid-crystalline compounds and/or additives. In general, it is advantageous to dissolve the desired amount of the component used in the smaller amount in the components constituting the main ingredient at an elevated temperature. Solutions of the components may also be mixed in organic solvents, for example in acetone, chloroform or methanol, and after thorough mixing the solvent is removed, for example by distillation. The invention further relates to a method for producing the LC medium according to the invention.

It will be apparent to those skilled in the art that the LC medium of the present invention may also comprise compounds in which, for example, H, N, O, cl, F has been replaced with a corresponding isotope (e.g. deuterium, etc.).

The following examples illustrate the invention without limiting it. However, it shows to the person skilled in the art the concept of a preferred mixture and preferably the compounds to be employed and their individual concentrations and combinations with one another. In addition, this example illustrates what properties and combinations of properties are available.

Preferred mixture components are shown in tables A1 and A2 below. The compounds shown in Table A1 are particularly suitable for LC mixtures having positive dielectric anisotropy. The compounds shown in Table A2 are particularly suitable for LC mixtures having negative dielectric anisotropy.

Table A1

In Table A1, m and n are each independently an integer from 1 to 12, preferably 1, 2, 3, 4, 5 or 6,k is 0, 1, 2, 3, 4, 5 or 6, and (O) C _m H _2m+1 Meaning C _m H _2m+1 Or OC (alpha) _m H _2m+1 。

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Table A2

In Table A2, m and n are each independently of the other an integer from 1 to 12, preferably 1, 2, 3, 4, 5 or 6,k is 0, 1, 2, 3, 4, 5 or 6 and (O) C _m H _2m+1 Meaning C _m H _2m+1 Or OC (alpha) _m H _2m+1 。

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In a first preferred embodiment of the invention, the LC media of the invention, in particular those having positive dielectric anisotropy, comprise one or more compounds selected from the group consisting of the compounds of table A1.

In a second preferred embodiment of the invention, the LC media of the invention, in particular those having negative dielectric anisotropy, comprise one or more compounds selected from the group consisting of the compounds of table A2.

Table B

Table B shows possible chiral dopants that may be added to the LC media of the present invention.

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The LC medium preferably contains 0 to 10 wt.%, in particular 0.01 to 5 wt.%, particularly preferably 0.1 to 3 wt.% of dopants. The LC medium preferably comprises one or more dopants selected from the group consisting of the compounds of table B.

Table C

Table C shows possible stabilizers that may be added to the LC medium of the present invention. Wherein n represents an integer of 1 to 12, preferably 1, 2, 3, 4, 5, 6, 7 or 8, and the terminal methyl group is not shown.

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The LC medium preferably contains 0 to 10% by weight, in particular 1 to 5% by weight, particularly preferably 1 to 1% by weight, of stabilizers.

The LC medium preferably comprises one or more stabilizers selected from the group consisting of the compounds of table C.

In addition, the following abbreviations and symbols are used:

V ₀ represents the threshold voltage at 20 ℃, the capacitance [ V]，

n _e Represents an extraordinary refractive index at 20℃and 589nm,

n _o represents the ordinary refractive index at 20℃and 589nm,

Δn represents optical anisotropy at 20℃and 589nm,

ε _⊥ represents the dielectric constant perpendicular to the director at 20 c and 1kHz,

ε _|| represents the dielectric constant parallel to the director at 20 c and 1kHz,

delta epsilon represents the dielectric anisotropy at 20 ℃ and 1kHz,

cl.p., T (N, I) represents a clear light spot [. Degree.C ],

γ ₁ represents the rotational viscosity [ mPa.s ] at 20 DEG C]，

K ₁ Represents the elastic constant at 20℃and the "splay" deformation [ pN ]]，

K ₂ Represents the elastic constant at 20℃and the "distortion" deformation [ pN]，

K ₃ Represents the elastic constant at 20℃and the "bending" deformation [ pN ]]。

All concentrations and ratios in this specification are expressed in weight percent unless otherwise specified and preferably refer to the corresponding whole mixture, including all solid or liquid crystal components, without solvent.

All temperature values indicated in the present application, e.g. melting point T (C, N), transition from smectic phase (S) to nematic phase (N) T (S, N) and clearing point T (N, I) are expressed in degrees celsius (°c), unless otherwise indicated. M.p. represents melting point, cl.p. =clearing point. Furthermore, c=liquid crystalline phase, n=nematic phase, s=smectic phase and i=isotropic phase. The data between these symbols represents the transition temperature.

All physical properties are and have been determined according to "Merck Liquid Crystals, physical Properties of Liquid Crystals" Status 1997, 11 months, merck KGaA, germany, and are suitable for temperatures of 20 ℃, and Δn is determined at 589nm and Δε is determined at 1kHz, unless explicitly stated otherwise in each case.

The term "threshold voltage" as used in the present invention relates to the capacitive threshold (V ₀ ) It is also referred to as the Freedericks threshold unless otherwise indicated. In an embodiment, the optical threshold is also as usual for a relative contrast of 10% (V ₁₀ ) Given.

Examples

A) Host mixture

Nematic LC host mixture N1 is formulated as follows.

Nematic LC host mixture N2 was formulated as follows.

Monomer(s)

RAFT reagent

Photoinitiator

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Polymerizable mixture

Preparation of the polymerizable mixture: a polymerizable LC medium for polymer wall formation was prepared by: the LC host, monomer, photoinitiator and optional RAFT agent are mixed and the resulting mixture is then homogenized by heating above its clear point.

The composition of the polymerizable mixture is shown in table 1 below.

Polymerizable mixtures C1 and C2 are comparative mixtures without RAFT agents. The polymerizable mixtures M1 to M5 are the mixtures according to the invention which contain RAFT agents.

TABLE 1

(the sum of M1 concentrations was 102%, please check)

Polymer wall formation

Test box: the test cartridge comprises two ITO coated 0.3mm thick glass substrates held apart by spacer particles or foils having a layer thickness of 3-4 microns and glued together by an adhesive (typically Norland, NEA 123). On top of the electrode layer, a polyimide alignment layer (Nissan SE-6514 or SE 2414) is applied and rubbed in parallel or antiparallel.

Wall formation:

the test cell was filled with LC medium and placed on a black, non-reflective surface. The photomask was placed on top of the test cell and the samples were subjected to UV radiation (Hg/Xe arc lamp, LOT QuantumDesign Europe, LS 0205). Emission spectrum emissions below 320nm are removed by a dichroic mirror.

UV intensity was measured at a wavelength of 365+/-10nm FWHM (for all steps).

Two UV irradiation steps were used:

UV1: at 4mW/cm ² 30min, followed by 10mW/cm ² 30min

UV2: at 25mW/cm ² 5min

Photomasks typically have patterns of equidistant lines of the same thickness. Unless otherwise stated, the line thickness is 140 microns and the line-to-line distance is 9 microns.

Characterization: the samples were analyzed under a polarization microscope. The isotropic polymer walls can be clearly distinguished from the regions containing birefringent LC. Wall width and LC incorporation in the polymer wall, pixel region defects caused by polymer contamination or LC misorientation (misalignment) caused by wall formation methods can be observed.

Device embodiment

The polymerizable LC mixtures C1, C2 and M1-M5 were each filled into a test cartridge and UV irradiation was performed under a photomask as set forth above.

Figures 2-9 show polarized microscopic images of test cartridges made from the polymerizable mixture after polymerization. The formed polymer walls may exhibit a black line form, which means that the mask pattern is reproduced in the reactive mixture.

Figures 2 and 3 show polarized microscopic images of the test cartridges made from polymerizable mixtures C1 and C2, respectively.

As can be seen in fig. 2, in the case of mixture C1, there is still a certain amount of LC material trapped inside the polymer walls (visible through the bright spots in the dark wall areas), due to the low degree of phase separation between the LC molecules and the formed polymer.

As can be seen in fig. 3, in the case of mixture C2, the LC molecular alignment in the pixel is disturbed due to the use of higher amounts of the di-reactive monomer.

Fig. 4-7 show polarized microscopic images of the test cartridges made from the polymerizable mixtures M1-M4, respectively.

As can be seen in fig. 4-7, for all mixtures, the polymer walls are formed and a significantly lower amount of LC material is trapped inside the walls, because there is a better phase separation between the LC molecules and the formed polymer. Also, the pixels exhibit good LC molecular alignment.

It can also be seen in fig. 7 (mixture M4), that even high amounts of di-reactive monomer (here 19%) can be used without disturbing the LC alignment when RAFT reagents are used.

Fig. 8 and 9 show polarized microscopic images of the test cartridge made from the polymerizable mixture M5 immediately after polymerization (fig. 8) and after heat treatment at 70 ℃ for 60min (fig. 9). It can be seen that polymer walls are formed with good phase separation and good LC alignment in the pixels. It can also be seen that the polymer walls and LC alignment are stable even after heat treatment. This example is also in contrast to fig. 1-7, which were made by using method UV2, to demonstrate that thermally stable and well formed polymer walls can be achieved after a very short process time.

Claims

1. A Liquid Crystal (LC) medium comprising a polymerizable component a and a liquid crystal component B, wherein component B comprises one or more mesogenic or liquid crystal compounds, and component a comprises

RAFT agent in an amount of 0.01% to 10% in LC medium, and

optionally a polymerization initiator, and a polymerization initiator,

characterized in that the RAFT agent is selected from formula I1a:

R ^a1 h, R of a shape of H, R ^b1 Or- (CH) ₂ CH ₂ O) _n -CH ₃ ，

k is 0 or 1, and the number of the groups is,

characterized in that component A comprises one or more polymerizable compounds of formula IIA:

P-Sp-G ² IIA

wherein P is selected from acrylic estersMethacrylate groups, sp is a spacer group or a single bond, and G ² Is a bicyclic or polycyclic hydrocarbon radical having 4 to 30 ring atoms, which is optionally substituted by one or more radicals L,

R ⁰ 、R ⁰⁰ is H or an alkyl group having 1 to 20C atoms,

Y ^z f or Cl.

2. LC medium according to claim 1, characterized in that G ² Is a bridged or fused bicyclic or polycyclic alkyl group.

3. LC medium according to claim 1 or 2, characterized in that component a comprises one or more polymerizable compounds selected from the group of formula II:

P-Sp-G ¹ II

p is selected from the group consisting of acrylate and methacrylate groups,

sp is a spacer group or a single bond,

G ¹ is a linear or branched alkyl group having 1 to 20C atoms or a monocyclic alkyl group having 3 to 24C atoms, which is optionally substituted by one or more groups L, and wherein one or more CH' s ₂ The radicals optionally being composed of-O-, -CO-, O-CO-or-CO-O-is replaced in such a way that O atoms are not directly adjacent to one another,

l has one of the meanings given in claim 1.

4. An LC medium according to claim 3, characterized in that G ¹ Optionally mono-, poly-or perfluorinated.

5. LC medium according to claim 1 or 2, characterized in that component a comprises one or more polymerisable compounds selected from the group consisting of the following subformulae:

P-Sp-(CHW ¹¹ ) _n2 -(CH ₂ ) _n1 -(CHW ¹² ) _n3 -CH ₃ II1

P-Sp-(CH ₂ ) _n2 -(CF ₂ ) _n1 -CFW ¹³ W ¹⁴ II2

p, sp has one of the meanings given in claim 3,

W ¹¹ 、W ¹² h, F or straight or branched C ₁ -C ₁₂ -an alkyl group, which is a group,

W ¹³ 、W ¹⁴ is H or F, and is not limited to the above,

n1 is an integer of 2 to 15,

n2 and n3 are 0 or integers from 1 to 3.

6. LC medium according to claim 1 or 2, characterized in that component a comprises one or more polymerisable compounds selected from the group consisting of the following subformulae:

wherein R in each occurrence identically or differently represents a P-Sp-as defined in claim 1 or has the meaning indicated for R in claim 1 ^q One of the meanings given and one group R in each of the formulae IIAA-IIAC represents P-Sp-.

7. LC medium according to claim 1 or 2, characterized in that component a comprises one or more polymerisable compounds selected from the group consisting of the following subformulae:

Wherein P and Sp have the meanings given in claim 3, W ¹¹ 、W ¹² W and W ¹³ H, F or C independently of one another ₁ -C ₁₂ -alkyl, and the cycloalkyl is optionally substituted with one or more groups L as defined in claim 1.

8. LC medium according to claim 1 or 2, characterized in that component a comprises one or more polymerizable compounds of formula III:

P ¹ -Sp ¹ -G ³ -Sp ² -P ² III

P ¹ 、P ² selected from the group consisting of acrylate and methacrylate groups,

Sp ¹ 、Sp ² is a spacer group or a single bond,

G ³ is a linear, branched or cyclic alkyl radical having from 1 to 20C atoms, optionally via one or more radicals P ¹ -Sp ¹ -or one or more groups L as defined in claim 1, and wherein one or more CH ₂ The radicals optionally being composed of-O-, -CO-, -O-CO-or-CO-O-is replaced in such a way that the O atoms are not directly adjacent to each other.

9. LC medium according to claim 8, characterized in that G ³ Optionally mono-, poly-or perfluorinated.

10. LC medium according to claim 1 or 2, characterized in that component a comprises one or more polymerisable compounds selected from the group consisting of the following subformulae:

P ¹ -Sp ¹ -(CHW ¹¹ ) _n2 -(CH ₂ ) _n1 -(CHW ¹² ) _n3 -Sp ² -P ² III 1

P ¹ -(CH ₂ ) _n2 -(CF ₂ ) _n1 -(CH ₂ ) _n3 -P ² III 3

(P ¹ -Sp ¹ -(CH ₂ ) _n4 ) _n5 CH _4-n5 III4

n1 is an integer of 2 to 15,

n2, n3 are each independently of the other 0 or an integer from 1 to 3,

n4 is 0 or an integer from 1 to 15,

n5 is 3 or 4 and is preferably selected from the group consisting of,

11. LC medium according to claim 1 or 2, characterized in that component a comprises one or more polymerisable compounds selected from the group consisting of the following subformulae:

CH ₂ ＝CW-CO-O-(CHW ¹¹ ) _n4 -(CH ₂ ) _n1 -O-CH＝CH ₂ III 1a

CH ₂ ＝CH-O-(CHW ¹¹ ) _n4 -(CH ₂ ) _n1 -O-CO-CW＝CH ₂ III 1b

CH ₂ ＝CW-CO-O-(CHW ¹¹ ) _n2 -(CH ₂ ) _n1 -(CHW ¹² ) _n3 -O-CO-III 1c

CW＝CH ₂

CH ₂ ＝CW-CO-O-(CH ₂ ) _n2 -(CF ₂ ) _n1 -(CH ₂ ) _n3 -O-CH＝CH ₂ III 3a

CH ₂ ＝CW-CO-O-(CH ₂ ) _n2 -(CF ₂ ) _n1 -(CH ₂ ) _n3 -O-CO-CW＝CH ₂ III 3b

(CH ₂ ＝CW-CO-O-(CH ₂ ) _n2 ) ₃ CH III 4a(CH ₂ ＝CW-CO-O-(CH ₂ ) _n2 ) ₄ C III 4b

wherein W is H, CH ₃ Or C ₂ H ₅ And W is ¹¹ 、W ¹² N1, n2 and n4 are as defined in claim 10, and the cyclohexylidene rings in formulae III2a to c are optionally interrupted by one or more identical or different radicals W ¹¹ And (3) substitution.

12. LC medium according to claim 1 or 2, characterized in that the concentration of RAFT agent in the LC medium is between 0.01% and 5% by weight.

13. LC medium according to claim 1 or 2, characterized in that component B comprises one or more compounds selected from formulae a and B:

each independently of the other and at each occurrence the same or different is

R ²¹ 、R ³¹ Each independently of the others is an alkyl, alkoxy, oxaalkyl or alkoxyalkyl group having from 1 to 9C atoms or an alkenyl or alkenyloxy group having from 2 to 9C atoms, which is optionally fluorinated,

X ⁰ F, cl, alkyl or alkoxy halides having 1 to 6C atoms or alkenyl or alkenyloxy halides having 2 to 6C atoms,

Z ³¹ is-CH ₂ CH ₂ -、-CF ₂ CF ₂ -, -COO-, trans-ch=ch-, trans-cf=cf-, -CH ₂ O-or a single bond,

L ²¹ 、L ²² 、L ³¹ 、L ³² each independently of the other is H or F,

g is 0, 1, 2 or 3.

14. LC medium according to claim 13, characterized in that component B comprises, in addition to the compounds of formulae a and/or B, one or more compounds of formula C:

wherein the individual radicals have the following meanings:

each independently of the other and

is identical or different at each occurrence

R ⁴¹ 、R ⁴² Each independently of the others is an alkyl, alkoxy, oxaalkyl or alkoxyalkyl group having from 1 to 9C atoms or an alkenyl or alkenyloxy group having from 2 to 9C atoms, which is optionally fluorinated,

Z ⁴¹ 、Z ⁴² each independently of the other is-CH ₂ CH ₂ -, -COO-, trans-ch=ch-, trans-cf=cf-, -CH ₂ O-、-CF ₂ O-, -C.ident.C-or a single bond,

h is 0, 1, 2 or 3.

15. LC medium according to claim 1 or 2, characterized in that component B comprises one or more compounds selected from formulae CY and PY:

wherein the method comprises the steps of

a represents a group consisting of 1 and 2,

b represents 0 or 1, and the number of the groups is,

representation->

R ¹ R is R ² Each independently of the others represents an alkyl radical having 1 to 12C atoms, where, in addition, one or two non-adjacent CH ₂ The radicals may be selected from the group consisting of-O-; -ch=ch-, -CO-, OCO-or-COO-is replaced in such a way that the O atoms are not directly connected to each other,

Z ^x z is as follows ^y Each independently of the other represents-CH ₂ CH ₂ -、-CH＝CH-、-CF ₂ O-、-OCF ₂ -、-CH ₂ O-、-OCH ₂ -、-CO-O-、-O-CO-、-C ₂ F ₄ -、-CF＝CF-、-CH＝CH-CH ₂ O-or a single bond,

16. LC medium according to claim 15, characterized in that component B comprises, in addition to the compounds of formula CY and/or PY, one or more compounds of formula ZK:

wherein the individual radicals have the following meanings:

representation->

Representation->

R ³ R is R ⁴ Each independently of the others represents an alkyl radical having 1 to 12C atoms, where, in addition, one or two non-adjacent CH ₂ The radicals may be selected from the group consisting of-O-; -ch=ch-, -CO-, O-CO-or-CO-O-is replaced in such a way that the O atoms are not directly connected to one another,

Z ^y represents-CH ₂ CH ₂ -、-CH＝CH-、-CF ₂ O-、-OCF ₂ -、-CH ₂ O-、-OCH ₂ -、-CO-O-、-O-CO-、-C ₂ F ₄ -、-CF＝CF-、-CH＝CH-CH ₂ O-or a single bond.

17. LC medium according to claim 1 or 2, characterized in that the polymerisable compound is polymerised by RAFT polymerisation.

18. An LC display comprising an LC medium according to any one of claims 1 to 17.

19. The LC display according to claim 18, which is a flexible or curved display.

20. The LC display according to claim 18 or 19, which is a TN, OCB, IPS, FFS, positive-VA, VA or UB-FFS display.

21. A method of producing an LC display according to any one of claims 18 to 20, comprising the steps of: providing the LC medium of any one of claims 1 to 17 into the display, and polymerizing the polymerizable compound in a defined region of the display by RAFT polymerization.

22. The method according to claim 21, wherein the polymerizable compound is photopolymerized by exposure to UV radiation.

23. The method according to claim 22, wherein the polymerizable compound is photopolymerized by exposure to UV radiation via a photomask.

24. A method of preparing an LC medium according to any one of claims 1 to 17, comprising the steps of: mixing a liquid-crystalline component B as defined in any of claims 1 and 13 to 17 with one or more polymerisable compounds or components a as defined in any of claims 1 to 12 and optionally further LC compounds and/or additives.