KR20130102012A - Cholesteric liquid crystal medium and liquid crystal display - Google Patents

Abstract

PURPOSE: A liquid crystal medium has a broadband reflection performance, a wide operation temperature range, a short response rate, a low critical voltage, low temperature dependence of a reflective wavelength, and especially high birefringence value. CONSTITUTION: A liquid crystal medium includes one or more non-polymerizable mesogenic compounds; one or more polymerizable chiral compounds; and one or more polymerizable non-chiral compounds. The liquid crystal medium has an optical anisotropy of 0.150 or higher. The polymerizable chiral compound includes a polymerizable chiral mesogenic compound. A composite material includes one or more mesogenic non-polymerizable compounds and a polymer obtainable from the medium. A liquid crystal display includes the liquid crystal medium and/or the composite material.

Description

CHOLESTERIC LIQUID CRYSTAL MEDIUM AND LIQUID CRYSTAL DISPLAY}

The present invention relates to a liquid crystal medium comprising an unpolymerizable mesogenic compound, a polymerizable chiral compound and a polymerizable non-chiral compound, which exhibits broadband reflection of visible light after polymerization of the polymer precursor in the medium. The invention also relates to liquid crystal displays comprising such media or the resulting composite material, in particular to displays operating in reflective mode and to displays operating in black / white mode.

Liquid crystal displays are known in the art. The most common display devices are based on the Schadt-Helfrich effect and include twisted nematic structures, such as TN ("twisted nematic") cells, typically with a torsion angle of 90 ° and typically between 180 and 270 It contains a liquid crystal medium having STN ("super twisted nematic") cells with a twist angle of °. The twisted structure in such displays is usually achieved by adding one or more chiral dopants to the nematic or smectic liquid crystal medium.

Liquid crystal displays containing liquid crystal (LC) media having chiral nematic or cholesteric structures are also known. This medium has a significantly higher twist compared to the medium of TN and STN cells.

The cholesteric liquid crystal exhibits selective reflection of circularly polarized light, and the direction of rotation of the light vector corresponds to the direction of rotation of the cholesteric helix. The reflection wavelength λ is given by the pitch p of the cholesteric helix and the average birefringence n of the cholesteric liquid crystal according to the following formula (1):

λ = n p (1)

Examples of conventional cholesteric liquid crystal (CLC) displays are the so-called SSCT ("surface stabilized cholesteric texture") and PSCT ("polymer stabilized cholesteric texture") displays. SSCT and PSCT displays usually have a planar structure that reflects light with a particular wavelength in the initial state, for example, and can be switched to a focally conical light scattering structure by applying an electrotransformation pulse or vice versa. It contains. When a stronger voltage pulse is applied, the CLC medium switches to a homeotropic transparent state, which is relaxed to a planar state after a fast switching-off of the voltage or to a conical focus state after a slow switching-off.

The initial state, for example, the planar alignment of the CLC medium before applying the voltage is achieved in the SSCT display, for example by surface treatment of the cell walls. In PSCT displays, the CLC medium additionally includes a phase-separated polymer or polymer network that stabilizes the structure of the CLC medium in each addressed state.

SSCT and PSCT displays generally do not require backlighting. In the planar state, the CLC medium in the pixel exhibits selective light reflection of a particular wavelength according to equation (1) above, which means that the pixel appears in the corresponding reflective color, for example in front of a black background. When changing to focusing conical scattering or homeotropic transparency, the reflection color disappears.

SSCT and PSCT displays are bistable. That is, each state is maintained after the electric field is switched off, and is switched to the initial state only when a new electric field is applied. Thus, for example, an LC medium in an addressed pixel will return to its initial state immediately after the electric field is switched off, which means that the maintenance of the addressed voltage is necessary for the continuous generation of pixels. Electro-optical TN or STN display In contrast, a short voltage pulse is sufficient to generate a pixel.

For the reasons mentioned above, CLC displays have significantly lower power consumption than TN or STN displays. In addition, they show little or no viewing angle dependence in the scattering state. In addition, they do not require active-matrix addressing in the case of TN displays, but can instead be operated in simple multiplex mode or passive-matrix mode.

WO 92/19695 and US Pat. No. 5,384,067 describe PSCT displays containing, for example, CLC media having a positive dielectric anisotropy and having up to 10% by weight of phase-separated polymer networks dispersed in liquid crystal materials. US 5,453,863 describes, for example, SSCT displays containing polymer-free CLC media with positive dielectric anisotropy.

CLC media for the aforementioned displays can be prepared, for example, by doping nematic LC media with chiral dopants with high torsional forces. The pitch p of the induced cholesteric helix is then given by the concentration c of the chiral dopant and the helix torsion HTP according to equation (2):

p = (HTP c) ^-1 (2)

In addition, two or more dopants may be used, for example, to compensate for the temperature dependence of the HTP of individual dopants to achieve low temperature dependence and reflection wavelength of the spiral pitch of the CLC medium. Total HTP (HTP _total ) is obtained by the following formula (3):

HTP _total = ∑ _i c _i HTP _i (3)

Where

c _i is the concentration of each individual dopant, and HTP _i is the spiral torsional force of each individual dopant.

For use in the aforementioned displays, chiral dopants must have very high spiral torsional forces and low temperature dependence, high stability and good solubility on the liquid crystal host. In addition, they should have a low deleterious effect to enable liquid crystal and electro-optical properties on the liquid crystal host. In particular, high helix torsional forces of the dopant are desirable, for example, in order to not only achieve a small pitch, but also to reduce the concentration of the dopant in cholesteric displays. This may firstly reduce the potential damage of the liquid crystal medium properties by the dopant, and secondly increase the latitude for the solubility of the dopant, such that a relatively low solubility dopant may be used.

In general, CLC materials for use in the aforementioned displays should have good chemical and thermal stability, and good stability to electric and electromagnetic radiation. In addition, the liquid crystal material should have a wide cholesteric liquid crystal phase having high clearing point, sufficiently high birefringence, high amount of dielectric anisotropy and low rotational viscosity.

In addition to properties such as different reflection wavelengths, CLC materials can be achieved by simple and targeted variations, especially in the visible light region. Herein, the use of polymerizable chiral reactive mesogens in LC mixtures is very suitable for monochromatic reflective CLC mode as described in WO 2010/022891 A1. Because of the photoreactivity of chiral reactive mesogens, the optical properties of the CLC mixture, such as the maximum reflected wavelength and the bandwidth of the reflected wavelength band, can be controlled by the irradiated UV energy, which is polymerized by polymerizing a specific amount of polymerizable chiral compound. It allows simple adjustment of the selective reflection wavelength so that it can no longer twist the liquid crystal material, leading to increased cholesteric pitch and consequently to reflection at longer wavelengths. In general, the range of reflection wavelengths for a particular color is less than 100 nm.

The term "polymerization" means a chemical process that combines with several polymerizable units or polymer precursors containing such polymerizable units to form a polymer.

Since liquid crystals are generally used in the form of a mixture of a plurality of components, it is important that the components can be easily mixed with each other. Additional properties such as dielectric anisotropy and optical anisotropy should meet different needs depending on the cell type.

However, it is not possible to achieve the desired values for all the above mentioned parameters using the medium available from the prior art.

Prior art CLC colored media have a reflection wavelength in the range of less than 100 nm and therefore have a specific color reflectance. Alternatively, for single layer reflective E-paper or E-book technology, a CLC mixture is required that exhibits broadband reflection of visible light with a better contrast ratio against black background.

Thus, for CLC media having broadband reflection characteristics, a wide operating temperature range, short response times, low threshold voltages, low temperature dependence of reflection wavelengths, in particular high birefringence values, and which have little or no disadvantages of media known in the art. There is a great demand for this.

Surprisingly, it has been found that liquid crystal media with suitable broadband reflection, suitably high Δε and Δn, and suitably low viscosity after polymerization of the polymerizable compound are feasible, which do not show the disadvantages of the materials of the prior art or to a lesser extent.

According to the present invention,

A) at least one non-polymerizable mesogenic compound

B) at least one polymerizable chiral compound, and

C) at least one polymerizable non-chiral compound

It relates to a liquid crystal medium comprising, preferably consisting of these.

The invention also relates to a composite material comprising a low molecular weight liquid crystal compound and a polymer obtainable or obtained from a liquid crystal medium as described above and below.

The invention also relates to a broadband reflective composite material obtainable or obtained by the polymerization of a liquid crystal medium as described above and below.

The invention also relates to the use of a broadband reflective composite material as described below and above in a broadband reflective optical display.

The invention also relates to the use of a broadband reflective composite material as described below and above in an optical or electro-optical component or device.

The invention also relates to an optical or electro-optical component or device comprising a broadband reflective composite material as described above and below.

Such devices and components include, but are not limited to, electro-optical displays, LCDs, optical films, polarizers, compensators, beam splitters, reflective films, alignment layers, color filters, hologram elements, hot stamping foils, color images, Decorative or security masking, LC pigments, adhesives, nonlinear optics (NLO) devices, optical information storage devices, electronic devices, organic semiconductors, organic field effect transistors (OFETs), integrated circuits (ICs), thin film transistors (TFTs), Radio frequency identification (RFID) tags, organic light emitting diodes (OLEDs), organic light emitting transistors (OLETs), discharge light displays, organic photovoltaic (OPV) devices, organic solar cells (O-SC), organic laser diodes (O-lasers), Organic integrated circuits (O-IC), lighting devices, sensor devices, electrode materials, photoconductors, photodetectors, electrophotographic recording devices, capacitors, charge injection layers, Schottky diodes, planarization layers, antistatic films, conductive Substrates, conductive patterns, Photoconductors, electrophotographic products, transcription photo recorders, organic storage devices, biosensors, biochips, optoelectronic devices requiring similar phase transitions at multiple wavelengths, combined CD / DVD / HD-DVD / Blu-rays, traces, recording, A re-recording data storage system, or a camera.

As described above, the high birefringent liquid crystal media of the present invention exhibit broadband reflection after polymerization of the polymer precursor. As a result, it can be used for bistable displays in black / white mode. In particular, the liquid crystal medium of the present invention exhibits the following useful properties:

High birefringence Δn (generally Δn> 0.150),

Imparting a stable cholesteric phase at ambient temperature, and

The polymer precursor in the liquid crystal medium can be polymerized into the composite material.

In addition, the resulting composite material exhibits reflection over a wide bandwidth of wavelengths typically having a width of at least 150 nm, preferably at least 200 nm, and very preferably at least 300 nm, in the visible spectrum (390-750 nm).

The liquid crystal medium of the present invention is generalized to meet the above criteria. In addition, the medium is particularly suitable for mass production and can be produced using industry standard equipment.

Such improved liquid crystalline media according to the present invention comprise at least one non-polymerizable mesogenic compound selected from the group of the following general formulas I to V:

I

I

Where

R ¹ is alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy, alkenyl, alkenyloxy, alkoxyalkyl, fluorinated alkenyl or fluorinated alkenyloxy, preferably alkyl or alkoxyalkyl and most preferred Preferably n-alkyl,

는

또는

이고,

The

or

ego,

L ¹¹ and L ¹² are, independently from each other, H or F, preferably L ¹¹ and L ¹² are F,

X ¹¹ is CN or NCS, preferably CN,

i is 0 or 1, preferably 0,

II

II

III

III

Where

R ² and R ³ are independently of each other alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 carbon atoms, alkenyl, alkenyloxy, alkoxyalkyl having 2 to 7 carbon atoms or Fluorinated alkenyl,

R ² and R ³ are preferably alkyl or alkenyl,

내지

는 서로 독립적으로,

To

Independently of one another,

또는

, 바람직하게는

or

, Preferably

이고,or

ego,

L ²¹ , L ²² , L ³¹ and L ³² are, independently from each other, H or F, preferably L ²¹ and / or L ³¹ are F,

X ²¹ and X ³¹ independently of one another are halogen, halogenated alkyl or alkoxy having 1 to 3 carbon atoms or halogenated alkenyl or alkenyloxy having 2 to 3 carbon atoms, preferably F, Cl , -OCF ₃ or -CF ₃ , most preferably F, Cl or -OCF ₃ ,

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, most preferably -COO-, trans-CH = CH- or a single bond,

l, m, n and o are independently of each other, optionally 0 or 1,

IV

IV

V

V

Where

R ⁴¹ to R ⁵² independently of one another have the meaning given for R ² in Formula II above, preferably R ⁴¹ is alkyl, R ⁴² is alkyl or alkoxy, or R ⁴¹ is alkenyl, R ⁴² is alkyl, preferably R ⁵¹ is alkyl, R ⁵² is alkyl or alkenyl, or R ⁵¹ is alkenyl, R ⁵² is alkyl or alkenyl, preferably alkyl,

및

는 서로 각각 독립적으로, 및

가 2개 존재하는 경우 이들 또한 독립적으로,

And

Are each independently of each other, and

Are present, they are also independently

이고,or

ego,

및

중 하나 이상은

이고,Preferably,

And

One or more of

ego,

및

는 서로 독립적으로, 및

가 2개 존재하는 경우 이들 또한 서로 독립적으로,

And

Are independent of each other, and

Are present, they are also independent of each other,

이고,

ego,

및

중 하나 이상은

또는

이고,Preferably,

And

One or more of

or

ego,

Z ⁴¹ to Z ⁵² are independently of each other, and when two Z ⁴¹ and / or Z ⁵¹ are present, they are also independently of each other: —CH ₂ CH ₂ —, —COO—, trans-CH═CH—, trans-CF = CF-, -CH ₂ O-, -CF ₂ O-, -C≡C- or a single bond, preferably at least one of Z ⁴¹ and Z ⁴² and at least one of Z ⁵¹ and Z ⁵² are each a single bond ego,

p and q are, independently from each other, 0, 1 or 2,

p is preferably 0 or 1,

Optionally, one or more compounds may be selected from the group of compounds of Formula III wherein n and o are both 1, Z ³¹ is preferably a single bond and all rings of the compound of Formula V are 1, 4-phenylene, which is, independently of each other, optionally fluorinated once or twice, q is 2, and Z ⁵¹ and Z ⁵² are preferably both single bonds.

Alternatively or in addition to the compounds of Formulas II and / or III, one or more genetic amounts of the compounds are selected from Formula VI:

VI

VI

Where

R ⁶ is alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 carbon atoms, alkenyl, alkenyloxy, alkoxyalkyl or fluorinated alkenyl having 2 to 7 carbon atoms, Preferably alkyl or alkenyl,

내지

는 서로 독립적으로,

To

Independently of one another,

이고,or

ego,

L ⁶¹ and L ⁶² are independently of each other, H or F, preferably L ⁶¹ is F,

X ⁶¹ is halogen, halogenated alkyl or alkoxy having 1 to 3 carbon atoms or halogenated alkenyl or alkenyloxy having 2 to 3 carbon atoms, preferably F, Cl, -OCF ₃ or -CF ₃ , most preferably F, Cl or -OCF ₃ ,

Z ⁶¹ is -CH ₂ CH _2- , -CF ₂ CF _2- , -COO-, trans-CH = CH-, trans-CF = CF- or -CH ₂ O-, preferably -CH ₂ CH ₂ -, -COO- or trans-CH = CH-, most preferably -COO- or -CH ₂ CH _2- ,

r is 0 or 1;

In a very preferred embodiment, the at least one compound of formula I is a compound of the following sub-formulas I-1 to I-5, preferably a compound of formulas I-2, I-4 and I-5 Preferably it is selected from compounds of the general formula (I-2):

Where

R ¹ has the respective meaning given in the general formula (I) above, preferably alkyl, most preferably n-alkyl and X ¹¹ is preferably CN.

In a preferred embodiment, the at least one compound is selected from the group of compounds of the general formulas II-1 and II-2, preferably compounds of the general formula II-2:

Where

The parameter has the respective meaning given in formula II above and X ²¹ is preferably F or —OCF ₃ .

Preferably, the at least one compound is selected from the group of compounds of formulas II-1 and II-2, wherein L ²¹ and L ²² are both F.

Preferably, the at least one compound of general formula II-1 is preferably selected from the group of compounds of general formulas II-1a to II-1c, preferably compounds of general formula II-1c:

Where

The parameters have their respective meanings given above, preferably

L ²¹ and L ²² are both F and L ²³ and L ²⁴ are both H,

L ²¹ , L ²² , L ²³ and L ²⁴ are both F.

In a preferred embodiment, L ²¹ , L ²² , L ²³ And at least one compound of formula II-1c wherein L ²⁴ is all F is selected.

Preferably, the at least one compound is selected from the group of compounds of the general formulas II-2a to II-2c, preferably compounds of the general formula II-2c:

Where

The parameters have the respective meanings given above, L ²³ to L ²⁷ are independent of each other, and independently of other parameters, H or F, preferably L ²¹ and L ²² are both F and L ²³ to L ²⁷ Two or three of them, most preferably L ²³ to L ²⁵ are F, the other of L ²¹ to L ²⁷ is H or F, preferably H, and X ²¹ is preferably F or -OCF ₃ and And most preferably F.

Particularly preferred compounds of formula II-2 are compounds of formula II-2c-1

Wherein R ² has the meaning given above.

In a further preferred embodiment of the invention, the at least one compound is selected from the group of compounds of the general formulas III-1 and III-2:

Where

The parameters have their respective meanings given in general formula III above.

Preferably, the at least one compound is a compound of general formula III-1, preferably a group of compounds of general formulas III-1a to III-1g, preferably of general formulas III-1a, III-1c and III- Selected from the group of compounds of 1e, most preferably each of the one or more compounds is of the following general formulas III-1a and / or III-1c and / or III-1e:

Where

The parameters have the respective meanings given above, and L ³³ to L ³⁷ are independent of each other and, independently of other parameters, are H or F, preferably L ³¹ and L ³² are both F and L ³³ to L ³⁷ Two or three of them, most preferably L ³³ to L ³⁵ are F, others of L ³¹ to L ³⁷ are H or F, preferably H and X ³¹ is preferably F or —OCF ₃ .

Most preferred compounds of formula III-1 are selected from the group of compounds of formula III-1a, III-1c-1, and III-1d-1:

Where

R ³ has the meaning given above.

Preferably, the compound of general formula IV is selected from the group of compounds of general formulas IV-1 to IV-7, more preferably compounds of general formulas IV-6 and / or IV-7:

Where

R ⁴¹ and R ⁴² have the respective meanings given in formula IV above, and in general and in particular in formulas IV-1 and IV-5, R ⁴¹ is preferably alkyl or alkenyl, preferably al Is kenyl, R ⁴² is preferably alkyl or alkenyl, preferably alkyl, alternatively in general formula IV-2, R ⁴¹ and R ⁴² are preferably alkyl, in general formula IV-4, R ⁴¹ is preferably alkyl or alkenyl, preferably alkyl, and R ⁴² is preferably alkyl or alkoxy, preferably alkoxy.

Preferably, the at least one compound is selected from the group of compounds of formulas IV-6 and IV-7, and most preferably, each of the at least one compound is of formulas IV-6 and IV-7.

Preferred compounds of the general formula IV-6 are compounds of the general formula CPTP-nm and CPTP-n-Om, more preferably compounds of the general formula CPTP-n-Om, but preferred compounds of the general formula IV-7 are general formula Compound of CPGP-nm. Definitions of such abbreviations (acronyms) are described in Tables A-C and illustrated in Table D below.

In a preferred embodiment, the at least one compound of formula V is selected from the group of compounds of formulas V-1 to V-6:

Where

R ⁵¹ and R ⁵² have the respective meanings given in formula V above, R ⁵¹ is preferably alkyl, more preferably n-alkyl, and in formula V-1, R ⁵² is preferably al Is kenyl, preferably 3-alkenyl, most preferably — (CH ₂ ) ₂ —CH═CH—CH ₃ , and in Formula V-3, R ⁵² is preferably alkyl or alkenyl, Preferably n-alkyl or 3-alkenyl, most preferably — (CH ₂ ) ₂ —CH═CH ₂ , in formulas V-3 to V-6, R ⁵² is preferably alkyl, In general formula V-4, "F _0/1 " is preferably F.

Preferred compounds of the general formula (V-1) are compounds of the general formulas PP-n-2V and PP-n-2Vm, more preferably compounds of the general formula PP-1-2V1. Preferred compounds of the general formula V-2 are compounds of the general formula PTP-n-Om, with compounds of the general formulas PTP-1-O2, PTP-2-O1 and PTP-3-O1 being particularly preferred. Preferred compounds of the general formula V-3 are compounds of the general formulas PGP-nm, PGP-n-2V and PGP-n-2Vm, more preferably of the general formulas PGP-2-m, PGP-3-m and PGP- compound of n-2V. Preferred compounds of the general formula V-4 are compounds of the general formula PPTUI-n-m, in particular compounds of the general formulas PPTUI-3-2, PPTUI-3-3, PPTUI-3-4 and PPTUI-4-4. Preferred compounds of formula V-5 are compounds of formula PGGIP-n-m. Preferred compounds of formula V-6 are compounds of formula PGIGP-n-m. Definitions of such abbreviations (acronyms) are described in Tables A-C and illustrated in Table D below.

Compounds of formula VI are preferably selected from the group of compounds of formulas VI-1 and VI-2, preferably compounds of formula VI-1:

Where

The parameters have the respective meanings described above, and the parameters L ⁶³ and L ⁶⁴ are independent of each other, and independently of the other parameters, H or F, preferably Z ⁶¹ is -CH ₂ -CH _2- , preferably X ⁶ is F.

The liquid crystal medium consists of several compounds, preferably 3 to 28, more preferably 4 to 18 and most preferably 4 to 14 compounds. These compounds are mixed in a conventional manner. Usually, a sufficient amount of the compound used in small amounts is dissolved in the compound used in large quantities. When the compound used in high concentration has reached a temperature above the clearing point, it is particularly easy to observe that the dissolution process is complete. However, the medium may also be employed using other conventional methods, such as the so-called multi-bottle-system, which is a component using so-called pre-mixtures or the mixtures themselves, which may be present in homologous or eutectic mixtures of compounds. It is possible to manufacture.

Preferably, the liquid crystalline medium is at least 0 ° C. or lower and 80 ° C. or higher, more preferably at least −20 ° C. or lower and 85 ° C. or higher, most preferably at least −20 ° C. or lower and 90 ° C. or higher, especially at least −30 ° C. or lower. To have a nematic phase in the range of at least 95 ° C.

As used herein, the expression “having a nematic phase” means that no clearing still occurs from the nematic phase upon heating, while no smetic phase and crystals are observed at low temperatures at the corresponding temperature. Observation at low temperatures is confirmed by performing at a corresponding temperature in a flow viscometer and storing in test cells having a layer thickness corresponding to electro-optical applications for at least 100 hours. The storage stability at a temperature of −20 ° C. in the corresponding test cell is at least 1000 hours and the medium is said to be stable at this temperature. At temperatures of −30 and −40 ° C., the corresponding times are 500 and 250 hours, respectively. At high temperatures, the clearing point is measured by conventional methods in capillaries.

The medium according to the invention comprises at least one polymerizable chiral compound. Such polymerizable chiral compounds may be non-mesogenic compounds or mesogenic compounds. Such polymerizable chiral compounds (which may be mesogenic or non-mesogenic) may be mono- or polyreactive, preferably di-reactive. Preferably, the medium may comprise both at least one mono-mono-reactive compound and at least one polyreactive compound, preferably a di-reactive compound. In particular, preference is given to substances comprising at least one direactive compound (crosslinker) which is preferably mesogenic, such as mesogenic, which may be based on the diacrylate type of reactive mesogen, preferably at least at the terminal, with a functional group. Do. The chiral polymerizable compound may comprise an acrylate / methacrylate group or another polymerizable group.

The mesogenic monomonoreactive chiral compounds used in the present invention preferably comprise one or more ring elements linked together by direct bonds or linkages, two of which may be linked to one another, optionally directly or by linking groups. And they may be the same or different from the linking groups mentioned. The ring element is preferably selected from the group of 4-, 5-, 6- or 7-, preferably 5- or 6-membered rings.

Preferably, the polymerizable chiral compounds used in the present invention are preferably each alone or in combination with each other, at least 20 μm ⁻¹ , preferably at least 40 μm ⁻¹ , more preferably at least 60 μm ⁻¹ , Most preferably, it has an absolute value (| HTP _total |) of the spiral torsional force of 80 μm ⁻¹ or more and 260 μm ⁻¹ or less.

Suitable polymerizable chiral compounds and their synthesis are described in US 7,223,450.

In a preferred embodiment, the polymerizable chiral compound used in the present invention is selected from compounds of the general formula CRM:

Where

R ^{0 *} is H or P ⁰ , P ⁰ is a polymerizable group,

A ⁰ and B ⁰ independently of one another in several occurrences are 1,4-phenylene, or trans-1,4-cyclo unsubstituted or substituted with 1, 2, 3 or 4 groups L as defined above. Hexylene,

X ¹ and X ² are, independently from each other, -O-, -COO-, -OCO-, -O-CO-O- or a single bond,

Z ^* is ^0, when the number of times out, each independently, -COO-, -OCO-, -O-CO -O-, -OCH 2 -, -CH 2 O-, -CF 2 O-, -OCF 2 -, -CH ₂ CH ₂ -,-(CH ₂ ) _4- , -CF ₂ CH _2- , -CH ₂ CF _2- , -CF ₂ CF _2- , -C≡C-, -CH = CH-, -CH = CH-COO-, -OCO-CH = CH- or a single bond,

t is, independently of each other, 0, 1, 2 or 3,

a is 0, 1 or 2,

b is 0 or an integer from 1 to 12,

z is 0 or 1,

Wherein the naphthalene ring may be further substituted with one or more identical or different groups L,

L is, independently from each other, F, Cl, CN, halogenated alkyl having 1 to 5 carbon atoms, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy.

The polymerizable group P ⁰ represents a group which can be used for polymerization reactions such as radical polymerization or ion chain polymerization, polyaddition or polycondensation or which can be grafted to the polymer backbone in polymer-like reactions by grafting such as condensation or addition. Particular preference is given to polymerizable groups for chain polymerization reactions such as radical, cation or anionic polymerization. Very preferred are polymerizable groups comprising —C═C— or —C≡C— bonds, and polymerizable groups which can be polymerized by the ring-opening reaction, such as oxetane or epoxide.

, CH₂=CW²-(O)_k1-, CH₃-CH=CH-O-, (CH₂=CH)₂CH-OCO-, (CH₂=CH-CH₂)₂CH-OCO-, (CH₂=CH)₂CH-O-, (CH₂=CH-CH₂)₂N-, (CH₂=CH-CH₂)₂N-CO-, HO-CW²W³-, HS-CW²W³-, HW²N-, HO-CW²W³-NH-, CH₂=CW¹-CO-NH-, CH₂=CH-(COO)_k1-Phe-(O)_k2-, CH₂=CH-(CO)_k1-Phe-(O)_k2-, Phe-CH=CH-, HOOC-, OCN-, 및 W⁴W⁵W⁶Si-를 포함하며, W¹은 H, F, Cl, CN, CF₃, 페닐 또는 1 내지 5개의 탄소 원자를 갖는 알킬, 특히 H, Cl 또는 CH₃이고, W² 및 W³은 서로 독립적으로, H 또는 1 내지 5개의 탄소 원자를 갖는 알킬, 특히 H, 메틸, 에틸 또는 n-프로필이고, W⁴, W⁵ 및 W⁶은 서로 독립적으로, Cl, 1 내지 5개의 탄소 원자를 갖는 옥사알킬 또는 옥사카본일알킬이고, W⁷ 및 W⁸은 서로 독립적으로, H, Cl 또는 1 내지 5개의 탄소 원자를 갖는 알킬이고, Phe은 바람직하게는 상기 정의된 바와 같은 하나 이상의 기 L(단 P-Sp- 제외)로 임의적으로 치환되는 1,4-페닐렌이고, k₁ 및 k₂는 서로 독립적으로, 0 또는 1이다.Suitable, preferred polymerizable groups P ⁰ include, but are not limited to, CH ₂ = CW ¹ -COO-, CH ₂ = CW ¹ -CO-,

, CH ₂ = CW ^2- (O) _k1- , 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-, HO-CW ² W ^3- , HS- ^{CW 2 W 3 -, HW 2} N-, HO-CW 2 W 3 -NH-, 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-, HOOC-, OCN-, and W ⁴ W ⁵ W ⁶ Si-, and include, W ¹ is H, F , Cl, CN, CF ₃ , phenyl or alkyl having 1 to 5 carbon atoms, in particular H, Cl or CH ₃ , W ² And W ³ are independently of each other, H or alkyl having 1 to 5 carbon atoms, in particular H, methyl, ethyl or n-propyl, W ⁴ , W ⁵ and W ⁶ are independently of each other Cl, 1 to 5 Oxaalkyl or oxacarbonylalkyl having 2 carbon atoms, W ⁷ and W ⁸ are independently of each other H, Cl or alkyl having 1 to 5 carbon atoms, and Phe is preferably one as defined above 1,4-phenylene optionally substituted with the above group L (except P-Sp-), and k ₁ and k ₂ are each independently 0 or 1.

, (CH₂=CH)₂CH-OCO-, (CH₂=CH-CH₂)₂CH-OCO-, (CH₂=CH)₂CH-O-, (CH₂=CH-CH₂)₂N-, (CH₂=CH-CH₂)₂N-CO-, HO-CW²W³-, HS-CW²W³-, HW²N-, HO-CW²W³-NH-, CH₂=CW¹-CO-NH-, CH₂=CH-(COO)_k1-Phe-(O)_k2-, CH₂=CH-(CO)_k1-Phe-(O)_k2-, Phe-CH=CH-, HOOC-, OCN-, 및 W⁴W⁵W⁶Si-로부터 선택되며, W¹은 H, F, Cl, CN, CF₃, 페닐 또는 1 내지 5개의 탄소 원자를 갖는 알킬, 특히 H, F, Cl 또는 CH₃이고, W² 및 W³은 서로 독립적으로, H 또는 1 내지 5개의 탄소 원자를 갖는 알킬, 특히 H, 메틸, 에틸 또는 n-프로필이며, W⁴, W⁵ 및 W⁶은 서로 독립적으로, Cl, 1 내지 5개의 탄소 원자를 갖는 옥사알킬 또는 옥사카본일알킬이고, W⁷ 및 W⁸은 서로 독립적으로, H, Cl 또는 1 내지 5개의 탄소 원자를 갖는 알킬이고, Phe은 바람직하게는 상기 정의된 바와 같은 하나 이상의 기 L(단 P-Sp- 제외)로 임의적으로 치환되는 1,4-페닐렌이고, k₁ 및 k₂는 서로 독립적으로, 0 또는 1이다.Very preferred polymerizable groups are CH ₂ = CW ¹ -COO-, CH ₂ = CW ¹ -CO-,

, (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-, HO-CW ² W ^3- , HS-CW ² W ^3- , HW ² N-, HO-CW ² W ³ -NH-, 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-, HOOC-, OCN-, and W ⁴ W ⁵ W ⁶ Si-, W ¹ is H, F, Cl, CN, CF ₃ , phenyl or alkyl having 1 to 5 carbon atoms, in particular H , F, Cl or CH ₃ , W ² and W ³ are independently of each other H or alkyl having 1 to 5 carbon atoms, in particular H, methyl, ethyl or n-propyl, W ⁴ , W ⁵ and W ⁶ is independently of each other, Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5 carbon atoms, W ⁷ and W ⁸ are independently of each other H, Cl or alkyl having 1 to 5 carbon atoms, Phe is preferably 1,4-phenylene optionally substituted with one or more groups L (except P-Sp-) as defined above And, k ₁ and k ₂ are independently of each other, 0 or 1.

및

로부터 선택된다. Most preferred polymerizable groups are CH ₂ = CH-COO-, CH ₂ = C (CH ₃ ) -COO-, CH ₂ = CF-COO-, (CH ₂ = CH) ₂ CH-OCO-, (CH ₂ = CH ) ₂ CH-O-,

And

.

The compound of general formula CRM is preferably selected from the group of compounds of general formula CRM-a:

Where

A ⁰ , B ⁰ , Z ^{0 *} , R ^{0 *} , a and b have the meaning given to the general formula CRM or one of the preferred meanings given above and below, and (OCO) represents —O—CO— or a single bond. Indicates.

Very preferred compounds of general formula CRM are selected from the group consisting of the following subformulae:

Where

R is -X ^2- (CH ₂ ) _x -R ^{0 *} as defined in general formula CRM-a, and the benzene and naphthalene rings are unsubstituted or 1, 2, 3 or 4 as defined above and below Groups L. Preferably R ^{0 *} is P ⁰ as defined below.

In addition, chiral compounds which are not polymerizable can optionally and advantageously be used in the medium according to the invention. Such non-polymerizable chiral compounds may be non-mesogenic compounds or mesogenic compounds.

Particular preference is given to nonpolymerizable chiral compounds with high helix torsional forces (HTP), especially those disclosed in WO 98/00428. Further typically used non-polymerizable chiral compounds are, for example, commercially available R / S-5011, R / S-811 or CB-15 (Merck Kagaea, Darmstadt, Germany).

Especially preferred are chiral compounds (including the respective (S, S) enantiomers) selected from the following general formulas VII and VIII:

Where

E and F are each independently 1,4-phenylene or trans-1,4-cyclohexylene, c is 0 or 1, Z is -COO-, -OCO-, -CH ₂ CH ₂ -or It is a single bond, and R ⁷ and R ⁸ are independently of each other alkyl, alkoxy or alkanoils having 1 to 12 carbon atoms.

Compounds of formula VII and their synthesis are described in WO 98/00428. Compounds of formula VIII and their synthesis are described in GB 2,328,207. Other suitable chiral compounds are known to those skilled in the art.

In addition, the medium according to the invention comprises at least one polymerizable non-chiral compound. Such polymerizable non-chiral compounds may be non-mesogenic compounds (eg, well known EHAs, and 2EHAs), or mesogenic compounds. Such polymerizable non-chiral compounds (which may be mesogenic or non-mesogenic) are mono- or polyreactive, and preferably may be direactive. Preferably, the medium comprises both at least one mono-mono-reactive compound and at least one multi-reactive compound, preferably a di-reactive compound. Most preferably, non-mesogenic compounds may additionally be present while the medium comprises one or more polymerizable non-chiral compounds. The polymerizable non-chiral compound may comprise an acrylate / methacrylate group or another polymerizable group.

Di- or polyreactive non-chiral compounds are preferably selected from general formula IX:

P-Sp-MG-Sp-P IX

Where

Sp is a spacer group or a single bond,

P ⁰ in each case, independently of one another, has the meaning given to the general formula CRM or one of the preferred meanings given above and below,

MG is preferably a rod-shaped mesogenic group selected from the following general formula X,

-(A ³ -Z ⁰ ) _d -A ⁴ -X

Where

A ³ and A ⁴ , independently of each other at each occurrence, contain an aromatic or cycloaliphatic group optionally containing one or more heteroatoms selected from N, O and S and optionally monosubstituted or polysubstituted with L as defined above. ego,

Z ⁰ is independently from each other at each occurrence: -O-, -S-, -CO-, -COO-, -OCO-, -S-CO-, -CO-S-, -O-COO-, -CO -NR ^0- , -NR ⁰ -CO-, -NR ⁰ -CO-NR ⁰⁰ , -NR ⁰ -CO-O-, -O-CO-NR ^0- , -OCH _2- , -CH ₂ O-, -SCH _2- , -CH ₂ S-, -CF ₂ O-, -OCF _2- , -CF ₂ S-, -SCF _2- , -CH ₂ CH ₂ -,-(CH ₂ ) _4- , -CF ₂ CH _2- , -CH ₂ CF _2- , -CF ₂ CF _2- , -CH = N-, -N = CH-, -N = N-, -CH = CR ^0- , -CY ¹ = CY ² -, -C≡C-, -CH = CH-COO-, -OCO-CH = CH- or a single bond,

R ⁰ and R ⁰⁰ independently of each other represent H or alkyl having 1 to 12 carbon atoms,

Y ¹ and Y ² independently of each other represent H, F, Cl or CN,

d is 1, 2, 3 or 4, preferably 1 or 2, most preferably 2.

Preferred groups A ³ and A ⁴ include but are not limited to furan, pyrrole, thiophene, oxazole, thiazole, thiadiazole, imidazole, phenylene, cyclohexylene, bicyclooctylene, cyclohexenylene, pyridine, Pyrimidine, pyrazine, azulene, indane, naphthalene, tetrahydronaphthalene, anthracene and phenanthrene, all of which are unsubstituted or substituted by 1, 2, 3 or 4 groups L as defined above .

Particularly preferred groups A ³ and A ⁴ are 1,4-phenylene, pyridine-2,5-diyl, pyrimidine-2,5-diyl, thiophene-2,5-diyl, naphthalene-2,6 -Diyl, 1,2,3,4-tetrahydro-naphthalene-2,6-diyl, indan-2,5-diyl, bicyclooctylene or 1,4-cyclohexylene, wherein One or two non-adjacent CH ₂ groups are optionally substituted with O and / or S, which group is unsubstituted or substituted with 1, 2, 3 or 4 groups L as defined above in formula CRM.

In a preferred embodiment, the polymerizable non-chiral compound of formula IX is selected from the general formula RM:

Where

Z ¹ and Z ² are, in each case, independently of one another, -COO-, -OCO-, -CH ₂ CH _2- , -CF ₂ O-, -OCF _2- , -C≡C-, -CH = CH -, -OCO-CH = CH-, -CH = CH-COO-, or a single bond,

P ⁰ has, in each case, independently of one another, a meaning given to the general formula CRM or one of the preferred meanings given above and below,

L has the meaning given to the general formula CRM, and preferably, independently of each other, in each case, F, Cl, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxy having 1 to 5 carbon atoms Selected from carbonyl, alkylcarbonyloxy or alkoxycarbonyloxy,

r is, in each occurrence, independently of one another, 0, 1, 2, 3 or 4,

x and y are, independently from each other, 0 or an integer equal to or different from 1 to 12,

u and v are 0 or 1, and when adjacent x or y is 0, u or v is 0.

Preference is given to compounds of the general formula RM, wherein Z ¹ and Z ² are different, with compounds of the general formula RM wherein Z ¹ and Z ² are the same.

Particular preference is given to compounds of the general formula RM in which the same u and v are 0 or 1, and compounds of the general formula RM in which u and v are not identical and are independently of each other 0 and / or 1.

Particularly preferred compounds of general formula RM are selected from the following general formulas:

Where

L, r, u, v, x and y have the meaning given to the general formula RM or one of the preferred meanings given above, and P ⁰ has the meaning given to the formula CRM and includes the preferred meaning of this group. Particular preference is given to compounds of the general formulas RM-a1, RM-a2 and RM-a3, in particular compounds of the general formula RM-a1.

Control of the reflection of the liquid crystal medium can be achieved by copolymerization of the non-chiral polymer precursor and the chiral polymer precursor, which after polymerization, is no longer involved in the twisting of the liquid crystal material in the liquid crystal host mixture. This leads to a composite material having a nonlinear deviation of cholesteric pitch in the medium and thus broadband reflection of the composite material due to the nonlinear deviation in irradiation intensity due to light loss in the medium during the progress of the copolymerization. The resulting variable cholesteric pitch can be advantageously stabilized against further changes, for example by the use of a suitable filter (such as a UV filter) that protects the liquid crystal from ambient radiation.

Polymerization is accomplished, for example, by exposing the polymerizable material to heating or actinic radiation. By actinic radiation is meant irradiation with light such as UV light, IR light or visible light, irradiation with X-rays or gamma rays or irradiation with high energy particles such as ions or electrons. Preferably the polymerization is carried out by UV irradiation. As a source of actinic radiation, for example, a single UV lamp or a set of UV lamps can be used. When using a high lamp power, the curing time can be shortened. Another possible source of actinic radiation is a laser such as a UV, IR or visible light laser.

The curing time depends inter alia on the reactivity of the liquid crystal mixture, the thickness of the coating layer, the type of polymerization initiator and the power of the UV lamp. The curing time is preferably 5 minutes or less, very preferably 3 minutes or less, and most preferably 1 minute or less. For mass production, short cure times of up to 30 seconds are preferred.

The polymerization process is not limited to one curing step. In addition, the polymerization can be carried out by two or more steps, wherein the film is continuously exposed to two or more lamps of the same type, or two or more different lamps. The curing temperatures of the different curing steps will be the same or different. Also, lamp power and dose from different lamps will be the same or different. In addition to the conditions described above, the process step may also include a heating step of exposing between different lamps as described, for example, in JP 2005-345982 A and JP 2005-265896 A.

Preferably, the polymerization is carried out in an electro-optical cell maintained at a temperature on the cholesteric phase of the chiral liquid crystal host mixture.

The polymerization of the liquid crystal medium is preferably carried out in the presence of a polymerization regulator which absorbs at the wavelength of actinic radiation in order to control the polymerization process. For this purpose, the liquid crystal medium preferably further comprises one or more polymerization regulators.

For example, when the polymerization process is carried out by irradiation with UV light, the photoinitiator can be used as a polymerization regulator for generating free radicals or ions that decompose under UV irradiation to initiate the polymerization reaction. In order to polymerize acrylate or methacrylate groups, radical photoinitiators are preferably used. In order to polymerize vinyl, epoxide or oxetane groups, cationic photoinitiators are preferably used. In addition, thermal polymerization initiators that decompose when heated to produce free radicals or ions that initiate polymerization may be used. Typical radical photoinitiators include, for example, ^(® Darocure) the said commercially available cure ^® (Irgacure ^®) or Darocure ^® (Ciba AG (Ciba AG)), for example, IRGACURE 651, IRGACURE 369 IRGACURE 907 or said to be. Typical cationic photoinitiators are, for example, UVI 6974 (Union Carbide).

In another preferred embodiment, the medium according to the invention preferably comprises a dichroic or LC photoinitiator, for example as described in EP 1 388 538 A1.

In addition, the liquid crystal medium may include one or more stabilizers or inhibitors such as commercially available Irganox ^® series (Ciba Age), such as Irganox 1076, to prevent undesirable continuous polymerization.

Liquid crystal media according to the invention may be present and, in a preferred embodiment, stabilized by the polymerization of each polymer precursor and consist of said at least one polymerizable compound and optionally at least one said initiator. Preferably the stabilized polymer has a liquid crystal material in the form of a polymer network, i.e. a low molecular weight, ie the non-polymerizable liquid crystal material / mesogenic material is present in a substantially continuous form arranged in nearly soft strands of the polymeric material. . Polymer network stabilized liquid crystals are described by Dierking, I., Adv. Mater. 12 , No. 3, pp. 167-181 (2000).

The liquid crystal medium according to the invention is characterized by a clearing point of at least 80 ° C., preferably at least 85 ° C. and very preferably at least 90 ° C.

At 589 nm (Na ^D ) and 20 ° C., the Δn of the liquid crystal medium according to the invention is preferably in the range of at least 0.150 and at most 0.350, more preferably at least 0.170 and at most 0.250 and most preferably at least 0.180 and at most 0.220. to be.

At 1 kHz and 20 ° C., the Δε of the liquid crystal medium according to the invention is preferably at least 10, preferably at least 15, more preferably at least 20 and most preferably at least 25, preferably at most 40, more Preferably it is 35 or less, More preferably, it is the range of 10 or more and 40 or less and most preferably 20-30 (or about 10-40).

The liquid crystal medium is characterized by a TN display operating at a second minimum transmission according to Gooch and Tarry with an optical retardation (d · Δn) in the range of preferably at least 1.0 and up to 1.1 μm for comparison. . However, they are preferably used as cholesteric liquid crystals, which are so-called chiral nematic liquid crystals having a variable cholesteric pitch, and preferably these cholesteric pitches have a reflection wavelength in the visible range of the electron spectrum, ie from 390 to 750 nm. It is selected to be in range.

The compounds of formula I are preferably used in a total concentration of 1 to 35%, more preferably 2 to 30%, more preferably 3 to 20% and most preferably 5 to 15% of the total mixture in the medium do.

The compounds of formulas II and III preferably have a total concentration of 40 to 80%, more preferably 45 to 75%, more preferably 50 to 70% and most preferably 55 to 65% of the total mixture in the medium Used together.

The compound of formula II is preferably used in a total concentration of 15 to 35%, more preferably 20 to 30% and most preferably 22 to 28% of the total mixture in the medium.

The compound of formula III is preferably used in a total concentration of 20 to 45%, more preferably 25 to 40% and most preferably 30 to 35% of the total mixture in the medium.

The compound of formula IV is preferably used in a total concentration of 10 to 35%, more preferably 15 to 30% and most preferably 20 to 25% of the total mixture in the medium.

The compound of formula V is preferably used in a total concentration of 10 to 30%, preferably 12 to 28% and most preferably 16 to 23% of the total mixture in the medium.

The compound of formula VI is preferably used in a total concentration of 0.1-30%, preferably 0.1-15% and most preferably 0.1-10% of the total mixture in the medium.

The chiral polymerizable compound, preferably a compound of formula CRM-a, is preferably in a total concentration of 0.1 to 5%, more preferably 0.1 to 7% and most preferably 0.1 to 10% of the total mixture in the medium. Used.

Non-chiral polymerizable compounds, preferably compounds of the general formula RM-a, preferably comprise from 0.1 to 5%, more preferably from 0.1 to 7% and most preferably from 0.1 to 10% of the total mixture in the medium Used as a concentration. In a preferred embodiment of the invention, the ratio of the total concentration of the non-chiral polymerizable compound to the total concentration of the chiral polymerizable compound is at least 0.2 to 1, preferably at least 0.5 to 1, very preferably 1 to 1, and Most preferably, it is 1.5 or more and 1 equivalent.

The concentration of the polymerization initiator in the liquid crystalline medium is preferably 0.01 to 8%, very preferably 0.02 to 5%, most preferably 0.03 to 4%.

The concentration of stabilizer in the liquid crystal medium is preferably 0.01 to 0.2%, very preferably 0.02 to 0.1%.

The liquid crystal medium according to the invention may contain further additives at ordinary concentrations. The total concentration of further constituents is in the range of 0.1 to 10%, preferably 0.1 to 6%, based on the total mixture. The concentration of the individual compounds each used is preferably in the range of 0.1 to 3%. The concentration of such additives and similar additives does not take into account the values and ranges of the concentrations of the liquid crystal components and compounds of the liquid crystal medium herein. It is also maintained at the concentration of the dichroic dye used in the mixture, which is not calculated when the concentration of the components of each of the compounds of the host medium is specified. The concentration of each additive is always given for the final doped mixture.

The liquid crystal medium according to the invention consists of several compounds, preferably 3 or 30, more preferably 4 to 20 and most preferably 4 to 16 compounds. These compounds are mixed in a conventional manner. Usually, a sufficient amount of the compound used in small amounts is dissolved in the compound used in large quantities. When the compound used in high concentration has reached a temperature above the clearing point, it is particularly easy to observe that the dissolution process is complete. However, it is also possible to prepare the medium using other conventional methods, such as the so-called multi-bottle-system, which is a component using so-called pre-mixes or the mixtures themselves, which may be present in homologous or eutectic mixtures of the compounds.

Preferably, the medium according to the invention comprises one or more compounds consisting of:

-A compound of formula I-2,

Compounds of the general formula II-1c, preferably compounds of the general formula PUQU-n-F,

A compound of formula II-2c, preferably a compound of formula II-2c-1,

A compound of formula III-1a, preferably a compound of formula III-1a-1,

A compound of formula III-1c, preferably a compound of formula III-1c12,

Compounds of the general formula III-1d, preferably compounds of the general formula III-1d-1,

Compounds of the general formula IV-6, preferably compounds of the general formulas CPTP-n-Om and / or CPTP-n-m,

Compounds of formula IV-7, preferably compounds of formula CPGP-n-Om and / or CPGP-n-m,

Compounds of the general formula V-1, preferably compounds of the general formula PP-n-mV and / or PP-n-mVl,

Compounds of the general formula V-2, preferably compounds of the general formula PTP-n-Om,

Compounds of the general formula V-3, preferably of the general formulas PGP-n-m and / or PGP-n-mV,

Compounds of the general formula V-4, preferably compounds of the general formula PPTUI-n-m,

A compound of formula CRM-a, preferably a compound of formula CRM-a7, and / or

Compounds of the general formula RM, preferably compounds of the general formula RM-a1.

Stabilizers as well as polymerization initiators are known from the literature or are commercially available. Compounds of liquid crystalline host mixtures, chiral polymerizable compounds and non-chiral polymerizable compounds (mesogenic or nonmesogenic) are described in the literature and in standard books of organic chemistry, such as, for example, Houben-Weyl, Methoden der organischen Chemie, Thieme-Verlag, Stuttgart, or by themselves can be synthesized analogously to known methods. Particularly suitable methods are described in US 6,203,724. Further suitable methods are also described below and in the examples.

For an overview of terms and definitions related to liquid crystals and mesogens, see Pure Appl. Chem. 73 (5), 888 (2001), C. Tschierske, G. Pelzl and S. Diele, Angew. Chem. 2004, 116, 6340-6368.

The term "mesogenic group" refers to a group capable of inducing liquid crystal (LC) phase behavior. Compounds comprising mesogenic groups do not have to exhibit the LC phase itself. It is also possible to show LC phase behavior in mixtures comprising other compounds (eg liquid crystal host mixtures) or when mesogenic compounds or mixtures thereof are polymerized. In short, the term "liquid crystal" is used for both mesogenic and LC materials.

The term “low molecular weight” means a molecule having a relative molecular weight of less than 2000 g / mol of the compound.

The term "reactive mesogen (RM)" means a polymerizable mesogenic or liquid crystalline compound which is preferably a monomeric compound.

The term "spacer" or "spacer group" is also referred to as "Sp" above and is known to those skilled in the art and described in Pure Appl. Chem. 73 (5), 888 (2001) and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368. Unless stated otherwise, the terms "spacer" or "spacer group" above and below denote flexible organic groups that connect mesogenic groups and polymerizable groups in the polymerizable mesogenic compounds.

Also, a polymerizable compound having one polymerizable group is referred to as a "monoreactive" compound, a compound having two polymerizable groups is a "direactive" compound, and a compound having more than two polymerizable groups is referred to as a "multireactive" compound. do. Also, compounds that do not have polymerizable groups are referred to as "non-reactive" compounds.

The term "polymerization" means a chemical process of forming a polymer by combining with various polymerizable units or polymer precursors containing such polymerizable units.

The term "polymer" means a long or large molecule consisting of chains or networks of many repeating units formed by chemical bonds with many small molecules called monomers. Polymers are formed by linking polymers, many monomer molecules, or polymer precursors.

A "polymer network" is a network in which all polymer chains are connected to each other to form a single macro entity by many crosslinks. The polymer network can occur in the following types:

Graft polymer molecules, wherein the at least one side chain is a branched polymer molecule that is structurally or arrangementally different from the main chain

Star polymer molecules, which are branched polymer molecules with a single branch point having various linear chains or arms. If the arms are identical, the star polymer molecules are said to be regular. If the adjacent arms consist of different repeating subunits, the star polymer molecules are said to be of various kinds.

Comb polymer molecules consisting of a main chain having at least two three-way branching points and a linear side chain. If the arms are the same, the comb polymer molecules are said to be regular.

Comb polymer molecules consisting of a main chain with linear unbranched side chains, wherein at least one branching point has at least four functionalities.

In addition, materials composed of such polymer molecules are called composite materials.

A "composite material" is a naturally occurring material made from two or more structural materials that are manufactured or have significantly different physical or chemical properties that remain individual and apparent in the macroscopic or microscopic category within the final structure. .

The term “chiral” is generally used to describe an object that does not overlap on a mirror image. An "non-chiral" (not chiral) object is the same object as on this mirror image.

In the present invention, the term "genetic positive" is used for compounds or components having Δε> 3.0, "genetic neutral" is -1.5 <Δε <3.0, and "genetic negative" is Δε <-1.5. Δε is measured at a frequency of 1 kHz and 20 ° C. The dielectric anisotropy of each compound is determined from the result of a solution of 10% of each individual compound in the nematic host mixture. If the solubility of each compound in the host medium is less than 10%, its concentration is reduced by a factor of 2 until the resulting medium is sufficiently stable to measure their properties. Preferably, however, the concentration is maintained above 5% in order to keep the significance of the result as high as possible. The capacity of the test mixture is measured in cells with homeotropic and homogeneous alignment. This kind of cell spacing is about 20 μm. The applied voltage is a rectangular wave with a frequency of 1 kHz and typically an effective value of 0.5 to 1.0 V, but this is always chosen below the critical capacitor of each test mixture.

Δε can be defined as (ε _∥ − ε _⊥ ), ε _{av .} Is (ε _∥ + 2ε _⊥ ) / 3. Medium ZLI-4792 for genetic amounts of compound and genetic neutral compound and medium ZLI-3086 for genetic negative compounds (all of which are available from Merk Kagaea, Germany) are used as host mixtures, respectively. The permittivity of the compound is determined from the individual values of the host medium changed upon addition of the compound of interest. This value is extrapolated to the concentration of 100% of the compound of interest.

Unless expressly stated otherwise, throughout this application all concentrations are given in mass percent, for each complete mixture, all temperatures are given in Celsius, and all differences in temperature are given in degrees Celsius. All physical properties are described in "Merck Liquid Crystals, Physical Properties of Liquid Crystals &quot;, Status Nov. 1997, Merck KGaA, Germany], and measured and given at a temperature of 20 ° C, unless expressly stated otherwise. Optical anisotropy (Δn) is measured at a wavelength of 589.3 nm. Dielectric anisotropy (Δε) is measured at a frequency of 1 kHz. In addition to all other electro-optical properties, the threshold voltage was measured with a test cell made at Merck Kaguea, Germany. The test cell for measuring Δε has a cell gap of about 20 μm. The electrode is a circular ITO electrode comprising an area of 1.13 cm ² and a protective ring. The alignment layer is lecithin in homeotropic orientation (ε _∥ ) and polyimide AL-1054 from Japan Synthetic Rubber in planar homogeneous orientation (ε _⊥ ). The capacitor is measured with a frequency response analyzer Solatron 1260 using a sine wave with a voltage of 0.3 V _rms . The test cells used matched the posterior and terry or the first minimum transmission according to the following, and have a selected cell spacing to have an optical delay, typically having a value of about 0.45 μm ⁻¹ . The light used for electro-optical measurements is white light. The set up used is a commercially available device from Autronic Melchers, Karlsruhe, Germany. The characteristic voltage was measured under vertical observation. Threshold (V ₁₀ )-mid gray (V ₅₀ )-and saturation (V ₉₀ ) voltages were measured for 10%, 50% and 90% relative contrast, respectively.

In the cholesteric liquid crystal mixture according to the invention, the birefringence Δn is defined as follows:

Δn = n _e -n _o (4)

Where

n _e is the specific refractive index, n _o is the general refractive index, and the average refractive index n _{av .} Is obtained by the following formula:

n _{av .} = ((2n _o ² + n _e ² ) / 3) ^1/2 (5)

Average refractive index n _{av .} And the general refractive index n _o can be measured using an Abbe refractometer. Δn can also be calculated from the above equation.

Another way to approximate the optical anisotropy of the cholesteric mixture is to measure the optical anisotropy of the host. This can be done by preparing a mixture other than the chiral component and measuring the optical anisotropy of the host mixture on the Abbe refractometer.

Another way to approximate the cholesteric optical anisotropy is to measure the optical anisotropy of the nematic host. The optical anisotropy of the nematic host will be very similar to the optical anisotropy of cholesteric liquid crystals that reflect visible light. Unless otherwise stated, the optical anisotropy values of the cholesteric material or film are as given above and below, and are obtained by this method.

The center of the reflection band λ _o , ie the reflection peak given by the formula:

λ _o = p * n _{av .} (6)

Where

p is the helical pitch length on the cholesteric, n _{av .} Is its average reflectance. The reflection band is measured using a spectrophotometer, and the center of the reflection band can also be described by the following equation:

λ _o = (λ _max -λ _min ) / 2 (7)

Where

λ _max and λ _min are the maximum and minimum wavelengths for the reflection band at half the reflection peak height.

Unless stated otherwise, the center of the reflection band λ _o is measured by measuring the reflection band using a UV-Vis spectrophotometer and measuring the maximum wavelength at half the reflection peak height.

The reflection bandwidth Δλ is defined as follows (8) and can also be represented by the following (9):

Δλ = (λ ₀ -Δn) / n _{av .} (8)

Δλ = λ _max -λ _min (9)

Unless otherwise stated, the reflection bandwidth (Δλ) is measured by measuring the reflection band of the cholesteric medium using a UV-Vis spectrophotometer and measuring the width of the reflection peak (FWHM) at half the reflection peak height. do.

The term "broadband reflection" preferably means reflection over a wide bandwidth of wavelengths typically having a width of at least 150 nm within the range of the visible spectrum (390-750 nm). Thus, the corresponding reflection color is white. In contrast, CLC colored media of the prior art have a specific reflection wavelength range within 100 nm with specific color reflectivity.

Unless expressly stated otherwise, it is to be understood that the plural forms of the terms used herein include the singular form and vice versa.

Throughout the description and claims of this specification, the words "comprises" and "comprises" and variations thereof, such as "comprising", mean "including, but not limited to," and do not intend or exclude other ingredients. Do not.

It will be appreciated that modifications may be made in the embodiments according to the invention while falling within the scope of the invention. Unless stated otherwise, each feature disclosed herein may be replaced by alternative features for the same, equivalent, or similar purpose. Thus, unless stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

All features disclosed herein may be combined in any combination, except combinations where at least some of these features and / or steps are mutually exclusive. In particular, the preferred features of the invention are applicable to all aspects of the invention and can be used in any combination. In addition, features described in non-essential combinations may be used separately (not in combination).

In the present application and especially in the examples below, the structure of the liquid crystal compound is represented by an abbreviation called "acronym". The conversion from abbreviation to the corresponding structure is in accordance with Tables A to C below.

All groups C _n H _{2n +1} , C _m H _{2m +1} and C _l H _{2l +1} are preferably straight chain alkyl groups having n, m and l carbon atoms, respectively, and all groups C _n H _2n , C and _m H _2m and C _l H _2l are preferably each _{(CH 2) n, (CH} 2) m and _{(CH 2) l, -CH =} CH- is preferably trans, and each E vinylene.

Table A lists the symbols used for the ring elements, Table B lists the symbols used for the linking groups, and Table C lists the symbols used for the left and right end groups of the molecules.

Table D lists exemplary nonpolymerizable mesogenic molecular structures with their respective symbols.

Table E lists exemplary polymerizable chiral mesogenic molecular structures with their respective symbols.

Table F lists exemplary nonpolymerizable chiral mesogenic molecular structures along with their respective symbols.

Table G lists exemplary polymerizable non-chiral mesogenic molecular structures along with their respective symbols.

Stabilizers that can be added to the mixtures according to the invention are described, for example, in Table H below.

Table A: Ring elements

Table B: Connectors

Table C:

In this case, n and m are each an integer, and "..." represents a space for other symbols in this table.

Preferably, the liquid crystal medium according to the invention comprises, in addition to the compounds of the general formula I, at least one compound selected from the group of compounds of the general formulas in the table below.

Table D

Table E

TABLE F

Table G

Table H

Example

The examples given below illustrate the invention and do not limit it in any way.

However, the physical properties and compositions have been exemplified by those skilled in the art to which such properties can be achieved and in which they can be modified. In particular, a combination of various properties that can be advantageously achieved is well defined to those skilled in the art.

It will be appreciated that the liquid crystal mixture has the combinations and properties given in the table below. These optical performances are investigated. In particular, their reflection spectra are recorded.

Example  One

Table 1: Composition and Properties of Liquid Crystal Mixture A-0 (eg, Liquid Crystal Host Mixture)

Example  One

4.51% chiral reactive mesogen CRM 1 (obtainable from Merck KGaA, Darmstadt, Germany) was added to 95.49% of mixture A-0 from Example 1 to have a relatively cholesteric pitch Each cholesteric mixture called -1 was prepared. The transition temperature (ie, clear point) of the mixture A-1 in the transition from the cholesteric liquid crystal phase to the isotropic phase is 77.0 ° C. Mixture A-1 shows reflection in the blue range of the spectrum.

Example  2

5.00% non-chiral reactive mesogen RM 1 (available from Merk Kagaea, Darmstadt, Germany) and 0.05% photoinitiator IRG 651 (available from Merk Kagaea, Darmstadt, Germany) Each cholesteric mixture called B-1 was prepared by adding 94.95% of mixture A-1 from Example 1. Mixture B-1 exhibits a maximum reflection wavelength (λ _max ) of 500 nm and a bandwidth (Δλ) of 60 nm.

Example  2.1 to 2.7

Example  2.1

5.00% non-chiral reactive mesogen RM-1 (available from Merk Kagaea, Darmstadt, Germany) and 0.05% photoinitiator IRG 651 (available from Merk Kagaea, Darmstadt, Germany) Each cholesteric mixture called B-2 was prepared by adding 94.95% of mixture A-1 from Example 1. This mixture was then irradiated with a UV lamp (Execure-w 3000) using a 320 nm cut-off filter and a dose of 1 J. Mixture B-2 exhibits a maximum reflection wavelength (λ _max ) of 575 nm and a bandwidth (Δλ) of 250 nm.

Example  2.2

5.00% non-chiral reactive mesogen RM-1 (available from Merk Kagaea, Darmstadt, Germany) and 0.05% photoinitiator IRG 651 (available from Merk Kagaea, Darmstadt, Germany) Each cholesteric mixture called B-3 was prepared by adding 94.95% of mixture A-1 from Example 1. This mixture was then irradiated with a UV lamp (Excure-w 3000) using a 320 nm cut-off filter and a dose of 2J. Mixture B-3 exhibits a maximum reflection wavelength (λ _max ) 600 nm and a bandwidth (Δλ) 300 nm.

Example  2.3

5.00% non-chiral reactive mesogen RM-1 (available from Merk Kagaea, Darmstadt, Germany) and 0.05% photoinitiator IRG 651 (available from Merk Kagaea, Darmstadt, Germany) Each cholesteric mixture called B-4 was prepared by adding 94.95% of mixture A-1 from Example 1. This mixture was then irradiated with a UV lamp (Execure-w 3000) using a 320 nm cut-off filter and a dose of 3J. Mixture B-4 exhibits a maximum reflection wavelength (λ _max ) 600 nm and a bandwidth (Δλ) 300 nm.

Example  2.4

5.00% non-chiral reactive mesogen RM-1 (available from Merk Kagaea, Darmstadt, Germany) and 0.05% photoinitiator IRG 651 (available from Merk Kagaea, Darmstadt, Germany) Each cholesteric mixture called B-5 was prepared by adding 94.95% of mixture A-1 from Example 1. This mixture was then irradiated with a UV lamp (Execure-w 3000) using a 320 nm cut-off filter and a dose of 5J. Mixture B-5 exhibits a maximum reflection wavelength (λ _max ) 600 nm and a bandwidth (Δλ) 300 nm.

Example  2.5

5.00% non-chiral reactive mesogen RM-1 (available from Merk Kagaea, Darmstadt, Germany) and 0.05% photoinitiator IRG 651 (available from Merk Kagaea, Darmstadt, Germany) Each cholesteric mixture called B-6 was prepared by adding 94.95% of mixture A-1 from Example 1. This mixture was then irradiated with a UV lamp (Excure-w 3000) using a 320 nm cut-off filter and a dose of 10J. Mixture B-6 exhibits a maximum reflection wavelength (λ _max ) 600 nm and a bandwidth (Δλ) 325 nm.

Example  2.6

5.00% non-chiral reactive mesogen RM-1 (available from Merk Kagaea, Darmstadt, Germany) and 0.05% photoinitiator IRG 651 (available from Merk Kagaea, Darmstadt, Germany) Each cholesteric mixture called B-7 was prepared by adding 94.95% of mixture A-1 from Example 1. This mixture was then irradiated with a UV lamp (Excure-w 3000) using a 320 nm cut-off filter and a dose of 30J. Mixture B-7 exhibits a maximum reflection wavelength (λ _max ) 600 nm and a bandwidth (Δλ) 350 nm.

Example  2.7

5.00% non-chiral reactive mesogen RM-1 (available from Merk Kagaea, Darmstadt, Germany) and 0.05% photoinitiator IRG 651 (available from Merk Kagaea, Darmstadt, Germany) Each cholesteric mixture called B-8 was prepared by adding 94.95% of mixture A-1 from Example 1. This mixture was then irradiated with a UV lamp (Excure-w 3000) using a 320 nm cut-off filter and a 50J dose. Mixture B-8 7 shows a maximum reflection wavelength (λ _max ) 600 nm and a bandwidth (Δλ) 350 nm.

The absorbance at Example 2 and the corresponding wavelengths of 2.1 to 2.7 for the loaded UV energy (J) is shown in Table 2 below.

[Table 2]

As shown in Table 2, polymerization of the sample is necessary for broadband reflection because only the resulting composite materials of Examples 2.1-2.7 exhibit broadband reflection as described above and below. In contrast, the non-polymerized mixture of Example 2 exhibits selective reflection.

Example  3

1.00% of non-chiral reactive mesogen RM-1 (available from Merk Kagaea, Darmstadt, Germany) and 0.05% photoinitiator IRG 651 (available from Merk Kagaea, Darmstadt, Germany) Each cholesteric mixture called C-1 was prepared by adding 98.95% of mixture A-1 from Example 1. This mixture was then irradiated with a UV lamp (Excure-w 3000) using a 320 nm cut-off filter and a 50J dose. Mixture C-1 shows the maximum reflection wavelength (λ _max ) 725 nm and bandwidth (Δλ) 50 nm.

Example  4

2.00% of non-chiral reactive mesogen RM-1 (available from Merk Kagaea, Darmstadt, Germany) and 0.05% photoinitiator IRG 651 (available from Merk Kagaea, Darmstadt, Germany) Each cholesteric mixture called C-2 was prepared by adding 97.95% of mixture A-1 from Example 1. This mixture was then irradiated with a UV lamp (Excure-w 3000) using a 320 nm cut-off filter and a 50J dose. Mixture C-2 shows the maximum reflection wavelength (λ _max ) 725 nm and bandwidth (Δλ) 75 nm.

Example  5.1 to 5.4

Example  5.1

3.00% of non-chiral reactive mesogen RM-1 (available from Merk Kagaea, Darmstadt, Germany) and 0.05% photoinitiator IRG 651 (available from Merk Kagaea, Darmstadt, Germany) Each cholesteric mixture called C-3 was prepared by adding 96.95% of mixture A-1 from Example 1. This mixture was then irradiated with a UV lamp (Excure-w 3000) using a 320 nm cut-off filter and a 50J dose. Mixture C-3 shows the maximum reflection wavelength (λ _max ) 725 nm and the bandwidth (Δλ) 300 nm.

Example  5.2

4.00% of non-chiral reactive mesogen RM-1 (available from Merk Kagaea, Darmstadt, Germany) and 0.05% of the photoinitiator IRG 651 (from Merk Kagaea, Darmstadt, Germany) Each cholesteric mixture called C-4 was prepared by adding 95.95% of mixture A-1 from Example 1. This mixture was then irradiated with a UV lamp (Excure-w 3000) using a 320 nm cut-off filter and a 50J dose. Mixture C-4 exhibits a maximum reflection wavelength (λ _max ) of 700 nm and a bandwidth (Δλ) of 350 nm.

Example  5.3

5.00% non-chiral reactive mesogen RM-1 (available from Merk Kagaea, Darmstadt, Germany) and 0.05% photoinitiator IRG 651 (available from Merk Kagaea, Darmstadt, Germany) Each cholesteric mixture called C-5 was prepared by adding 94.95% of mixture A-1 from Example 1. This mixture was then irradiated with a UV lamp (Excure-w 3000) using a 320 nm cut-off filter and a 50J dose. Mixture C-5 exhibits a maximum reflection wavelength (λ _max ) 600 nm and a bandwidth (Δλ) 350 nm.

Example  5.4

7.00% of non-chiral reactive mesogen RM-1 (available from Merk Kagaea, Darmstadt, Germany) and 0.05% photoinitiator IRG 651 (available from Merk Kagaea, Darmstadt, Germany) Each cholesteric mixture called C-6 was prepared by adding 92.95% of mixture A-1 from Example 1. This mixture was then irradiated with a UV lamp (Excure-w 3000) using a 320 nm cut-off filter and a 50J dose. Mixture C-6 exhibits a maximum reflection wavelength (λ _max ) 600 nm and a bandwidth (Δλ) 350 nm.

The absorbances at Examples 3, 4 and corresponding wavelengths of 5.1 to 5.4 for the total concentration of non-chiral polymer precursor PRM 1 in the mixture are shown in Table 3.

[Table 3]

As shown in Table 3, the resulting composite materials of Examples 5.1-5.4 exhibit broadband reflection as described above and below, while the mixtures of Examples 3 and 4 exhibit selective reflection.

Example  6

Table 4: Composition and Properties of Liquid Crystal Mixture D-0 (eg, Liquid Crystal Host Mixture)

Example  6

4.51% of chiral reactive mesogen CRM-1 (obtained from Merk Kagaea, Darmstadt, Germany) was added to 95.49% of mixture D-0 from Example 1 to have a relatively cholesteric pitch Each cholesteric mixture called was prepared. The transition temperature (ie, clear point) of the mixture D-1 for the transition from the cholesteric liquid crystal phase to the isotropic phase is 76.0 ° C. Mixture D-1 shows reflection in the blue range of the spectrum.

Claims (15)

A) at least one non-polymerizable mesogenic compound
B) at least one polymerizable chiral compound, and
C) at least one polymerizable non-chiral compound
Liquid crystal medium comprising a. The method of claim 1,
A liquid crystal medium characterized by having an optical anisotropy (Δn) of 0.150 or more. 3. The method according to claim 1 or 2,
Wherein said polymerizable chiral compounds, each alone or in combination with one another, have an absolute value of spiral torsional force (| HTP _total |) of at least 20 μm ⁻¹ . The method according to any one of claims 1 to 3,
A liquid crystalline medium, characterized in that the polymerizable chiral compound comprises a polymerizable chiral mesogenic compound. The method according to any one of claims 1 to 4,
A liquid crystalline medium, characterized in that the polymerizable chiral compound comprises a compound selected from the group of the following general formula CRM:

In this formula,
R ^{0 *} is H or P ⁰ , P ⁰ is a polymerizable group,
A ⁰ and B ⁰ independently of one another in several occurrences are 1,4-phenylene, or trans-1,4-cyclo unsubstituted or substituted with 1, 2, 3 or 4 groups L as defined above. Hexylene,
X ¹ and X ² are, independently from each other, -O-, -COO-, -OCO-, -O-CO-O- or a single bond,
Z ^* is ⁰ when coming out several times independently of one another, -COO-, -OCO-, -O-CO -O-, -OCH 2 -, -CH 2 O-, -CF 2 O-, -OCF 2 -, - CH ₂ CH ₂ -,-(CH ₂ ) _4- , -CF ₂ CH _2- , -CH ₂ CF _2- , -CF ₂ CF _2- , -C≡C-, -CH = CH-, -CH = CH-COO-, -OCO-CH = CH- or a single bond,
t is, independently of each other, 0, 1, 2 or 3,
a is 0, 1 or 2,
b is 0 or an integer from 1 to 12,
z is 0 or 1,
Wherein the naphthalene ring may be further substituted with one or more identical or different groups L,
L is, independently from each other, F, Cl, CN, halogenated alkyl having 1 to 5 carbon atoms, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy. 6. The method according to any one of claims 1 to 5,
A liquid crystalline medium, characterized in that the polymerizable non-chiral compound comprises a polymerizable non-chiral mesogenic compound. 7. The method according to any one of claims 1 to 6,
A liquid crystalline medium, characterized in that the polymerizable chiral compound comprises a compound selected from the group of the general formula RM:

In this formula,
Z ¹ and Z ² are independently of each other at each occurrence: -COO-, -OCO-, -CH ₂ CH _2- , -CF ₂ O-, -OCF _2- , -C≡C-, -CH = CH- , -OCO-CH = CH-, -CH = CH-COO- or a single bond,
P ⁰ has the meaning given in the general formula CRM,
L has the meaning given in the formula CRM, preferably independently of each other at each occurrence is F, Cl, CN or optionally halogenated alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl having 1 to 5 carbon atoms , Alkylcarbonyloxy or alkoxycarbonyloxy,
r is independently of each other at each occurrence 0, 1, 2, 3 or 4,
x and y are independently of each other, 0 or the same or different integer between 1 and 12,
u and v are 0 or 1, where u or v is 0 when adjacent x or y is zero. The method according to any one of claims 1 to 7,
Wherein said non-polymerizable mesogenic compound comprises at least one compound selected from the group of formulas (I) to (V):

I
[In the above formula,
R ¹ is alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy, alkenyl, alkenyloxy, alkoxyalkyl, fluorinated alkenyl or fluorinated alkenyloxy,

The

or

ego,
L ¹¹ and L ¹² are, independently from each other, H or F,
X ¹¹ is CN or NCS,
i is 0 or 1;

II

III
[In the above formula,
R ² and R ³ are independently of each other alkyl, alkoxy, fluorinated alkyl or fluorinated alkoxy having 1 to 7 carbon atoms, alkenyl, alkenyloxy, alkoxyalkyl having 2 to 7 carbon atoms or Fluorinated alkenyl,

To

Independently of one another,

or

ego,
L ²¹ , L ²² , L ³¹ and L ³² are H or F,
X ²¹ and X ³¹ are, independently from each other, halogen, halogenated alkyl or alkoxy having 1 to 3 carbon atoms, or halogenated alkenyl or alkenyloxy having 2 to 3 carbon 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, m, n and o are each independently 0 or 1;

IV

V
[In the above formula,
R ⁴¹ to R ⁵² , independently of each other, have the meaning given for R ² in Formula II,

And

Are independent of each other, and

Are present, they are also independent of each other,

or

ego,

And

Are independent of each other, and

Are present, they are also independent of each other,

ego,
Z ⁴¹ to Z ⁵² are independently of each other, and when two Z ⁴¹ and / or Z ⁵¹ are present, they are also independently of each other: —CH ₂ CH ₂ —, —COO—, trans-CH═CH—, trans-CF = CF-, -CH ₂ O-, -CF ₂ O-, -C≡C- or a single bond,
p and q are 0, 1 or 2, independently of each other. The method according to any one of claims 1 to 8,
A liquid medium comprising chiral polymerizable compounds in a total concentration of at least 0.1% and up to 10% of the total mixture and non-chiral polymerizable compounds in a total concentration of at least 0.1% and up to 10% of the total mixture . 10. The method according to any one of claims 1 to 9,
Liquid crystal medium further comprising at least one polymerization regulator. 11. The method according to any one of claims 1 to 10,
A liquid crystal medium characterized by having a bandwidth of a wavelength reflected in the visible light range of the electron spectrum. 12. A composite material comprising at least one nonpolymerizable mesogenic compound and a polymer obtainable from the medium according to any one of claims 1 to 11. Use of the composite material according to claim 13 in liquid crystal displays. A process for producing a composite material according to claim 12 by polymerization of a polymer precursor in a liquid crystal medium according to claim 1. Liquid crystal display comprising a liquid crystal medium according to any one of claims 1 to 11 and / or a composite material according to claim 12.