Purification device for a liquid-crystal mixture

Abstract

A purification device (1), for the purification of a liquid-crystal mixture, has a flow chamber (2) which has an inlet opening (3) and an outlet opening (4), arranged opposite the inlet opening, in order to be able to introduce the liquid-crystal mixture into the flow chamber (2) and discharge it from the latter, and at least one flow distribution element (5) which is arranged in the flow chamber (2) in the region of the inlet opening (3), and at least one filter element (6) which is arranged in the region of the outlet opening (4), where a length of the flow chamber (2) measured in the flow direction is at least a factor of 2 greater than a greatest internal dimension of the flow chamber (2) transverse to the flow direction.

Claims

1. A purification device (1) comprising a flow chamber (2) having at least one sidewall, a top wall arranged at one end part of the sidewall, and a bottom wall arranged at the opposite end part of the sidewall, wherein the top wall has an inlet opening (3) and the bottom wall has an outlet opening (4), wherein a direction from the inlet opening to the outlet opening define a flow direction, wherein the inlet opening is suitable for introducing a liquid-crystal mixture into the flow chamber (2) and the outlet opening is suitable for discharging said liquid-crystal mixture, having at least one inlet flow distributor (5) which is arranged in the flow chamber (2) adjacent the inlet opening (3), and having at least one outlet filter (6) which is arranged in the flow chamber (2) spaced above the outlet opening (4), wherein a sorbent which functions as a purification agent is arranged in the flow chamber (2) between the inlet flow distributor (5) and the outlet filter (6), wherein said sorbent is at least one of an aluminum oxide, modified silica gel, magnesium silicate, silica gel and zeolite, an annular seal (9) in sealing contact with an inner surface of the top wall, an inner peripheral surface of the sidewall, and an outer peripheral edge of the inlet flow distributor (5) to seal the peripheral edge of the inlet flow distributor (5) to the sidewall and to prevent the liquid crystal mixture from escaping from the flow chamber (2), wherein the purification device contains said liquid-crystal mixture in the flow chamber and wherein the liquid-crystal mixture in the flow chamber contains at least three liquid-crystalline compounds, and wherein said liquid-crystal mixture is in the flow chamber, and contains a compound of formula I, ##STR00381## in which R.sup.1 and R.sup.2 each, independently of one another, denote H, an alkyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, in which one or more CH.sub.2 groups are optionally replaced by O, S, ##STR00382## CC, CHCH, CF.sub.2O, OCF.sub.2, OCO or OCO in such a way that O atoms are not linked directly to one another, and one of the radicals R.sup.1 and R.sup.2 also denotes F, Cl, CN, SF.sub.5, NCS, SCN or OCN, rings A, B, C, D and E each, independently of one another, denote ##STR00383## ##STR00384## ##STR00385## r, s and t each, independently of one another, denote 0, 1, 2 or 3, where r+s+t3, Z.sup.1-4 each, independently of one another, denote COO, OCO, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, CH.sub.2CH, (CH.sub.2).sub.4, CHCHCH.sub.2O, C.sub.2F.sub.4, CH.sub.2CF.sub.2, CF.sub.2CH.sub.2, CFCF, CHCF, CFCH, CHCH, CC or a single bond, and L.sup.1 and L.sup.2 each, independently of one another, denote H or F.

2. The purification device (1) according to claim 1, wherein the flow chamber (2) or at least a section of said flow chamber has a columnar shape, wherein D in said columnar shape is a diameter.

3. The purification device (1) according to claim 1, having at least inlet one filter (6) arranged in the flow chamber (2) adjacently below and in contact with the inlet flow distributer (5), and having at least one outlet flow distributor (5) arranged in the flow chamber (2) adjacent the outlet opening (4) and adjacently below and in contact with the outlet filter (6).

4. The purification device (1) according to claim 3, wherein a length in the flow chamber (2) measured in the flow direction from the inlet filter (6) to the outlet filter (6), designated as L, is greater than a greatest internal linear dimension of the flow chamber (2) transverse to the flow direction, designated as D.

5. The purification device (1) according to claim 4, wherein L is 2 to 34 times D.

6. The purification device (1) according to claim 1, wherein the sidewall is made from metal, plastic or a metal/plastic composite material.

7. The purification device (1) according to claim 1, wherein the flow chamber (2) has inside surfaces (7), and an adhesion-reducing internal coating is present on said inside surfaces (7).

8. The purification device (1) according to claim 1, wherein the flow chamber (2) has inside surfaces (7), and said inside surfaces (7) have a roughness of less than 1.0 m.

9. The purification device (1) according to claim 1, wherein heating and/or cooling elements are mounted on the purification device (1).

10. The purification device (1) according to claim 1, wherein the at least one flow distribution element (5) at the inlet opening (3) is carried by the top wall, and wherein the top wall is detachably attached to the sidewall via a clamp connection (8).

11. The purification device (1) according to claim 1, wherein a connector (10) in the form of a hollow cylinder is arranged at said inlet opening 3 and/or said outlet opening 4.

12. The purification device (1) according to claim 1, wherein a connector (10) in the form of a hollow cylinder is arranged at said inlet opening 3 and/or said outlet opening 4, which connector (10) has quick-fit connectors (11) for connection to a container.

13. The purification device (1) according to claim 1, wherein a connector (10) in the form of a hollow cylinder is arranged at said inlet opening 3 and/or said outlet opening 4, which connector is sealed by a cover 12.

14. A method for the purification of a liquid crystal mixture, comprising passing said liquid crystal mixture through the purification device (1) according to claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows a purification device 1, which has a flow chamber 2 having a columnar interior. A sorption agent (not depicted), which carries out the sorption of the substances to be removed from the liquid-crystal mixture, such as, for example, polar compounds, particles, water, solvents, etc., is arranged in the flow chamber 2.

(2) FIG. 2 shows that the purification device (1) is made from metal, from plastic or from a metal/plastic composite material; that seal (9) is a plate seal, an O-ring seal or a jacketed O-ring seal; and that the length (L) of the flow chamber is at least a factor of 2 to 34 greater than the greatest internal dimension (ID).

(3) FIG. 3 shows that the purification agent (13) is arranged in the flow chamber, and can be a sorbent or a surface-active sorbent, or an aluminium oxide, modified silica gel, magnesium silicate, silica gel and/or zeolite.

(4) FIG. 4 shows an adhesion-reducing internal coating (14) is applied to the inside surfaces (7) of the flow chamber (2).

(5) FIG. 5 shows that heating and/or cooling elements (15) are mounted on the purification device (1).

(6) The liquid-crystal mixture can be introduced into the flow chamber 2 via an inlet opening 3 arranged at the top in the FIGURE and can flow out of the flow chamber 2 again via an outlet opening 4 arranged opposite the inlet opening.

(7) An inlet flow distribution element 5, which is in contact with an inlet filter element 6, is arranged immediately adjacent to the inlet opening 3. The liquid-crystal mixture is passed into the interior of the flow chamber 2 through the flow distribution element 5 and the inlet filter element 6. The flow distribution element 5 distributes the liquid-crystal mixture flowing in through the comparatively narrow inlet opening 3 uniformly over the entire cross-sectional area of the columnar interior of the flow chamber 2, so that the maximum effective contact duration of the liquid-crystal mixture flowing through with the sorption agent or the surface-active sorbent is achieved. An outlet flow distribution element 5, which is in contact with an outlet filter element 6, is arranged immediately adjacent to the outlet opening 4. The liquid-crystal mixture is passed out of the interior of the flow chamber 2 through the outlet filter element 6 and the outlet flow distribution element 5.

(8) In order, in spite of the flow resistance generated by the flow distribution element 5 and by the filter element 6, to prevent undesired exit of the often pressurized inflowing liquid-crystal mixture in the region of the inlet opening 3 from the purification device 1 and in order to ensure safe filling of the flow chamber 2, an annular seal 9 is provided in the region of the inlet opening 3. The seal 9 is in contact with the flow distribution element 5. The connection between the seal 9 and the flow distribution element 5 is ensured by a connection means 8, which, in the case of the present illustrative embodiment, is a clamp connection. As shown in FIG. 1, the annular seal (9) is in sealing contact with an inner surface of the top, an inner peripheral surface of the sidewall, and an outer peripheral edge of the inlet flow distributor (5) to seal the peripheral edge of the inlet flow distributor (5) to the sidewall and to prevent the liquid crystal mixture from escaping from the flow chamber (2).

(9) The flow distribution element 5 is designed in such a way that it covers at least 50%, or, in the case of the illustrative embodiment depicted, more than 75%, of the surface of the filter element 6. This results in the liquid-crystal mixture being distributed over virtually the entire width of the flow chamber 2 before entry into the flow chamber 2 and at the same time being pre-filtered. This can considerably improve the sorption process and shorten the reaction time.

(10) In the illustrative embodiment depicted in FIG. 2, the flow direction runs from the inlet opening 3 arranged at the top to the outlet opening 4 arranged at the bottom. The flow chamber 2 has a length L in the flow direction from the inlet filter (6) to the outlet filter (6) which is greater than the diameter D and thus than a greatest internal dimension of the flow chamber 2 transverse to the flow direction. The length L can be 2 to 34 times the diameter D. Surprisingly, it has been found that, for certain liquid-crystal mixtures, a length: diameter ratio of this type achieves a short reaction time and sufficiently good purification quality, which is reflected in improved efficiency.

(11) In order to exclude contamination of the liquid-crystal mixture with sorption agent, a filter element 6 is likewise arranged in the region of the outlet opening 4. A further flow distribution element 5 in front of the outlet opening 4 ensures that the stream split up by the first flow distribution element 5 in the region of the inlet opening 3 is re-combined and fed into a connector 10. The liquid-crystal mixture can subsequently be introduced into a container, not depicted, which can be connected to the purification device 1 by means of a suitable connection means 11 (for example a clamp connection).

(12) The connector 10 has a covering means 12 (in the present illustrative embodiment a lid cap), which is detachably attached to the connector 10. The covering means 12 is fixed to the connector 10 with the aid of a further clamp connection, enabling simple and rapid installation.

(13) The purification device 1 has a symmetrical design, i.e. the inlet opening 3 and the outlet opening 4 can also be interchanged and the flow direction intended for a purification operation can be reversed. A flow distribution element 5 and a filter element 6 are in each case arranged on both sides or at both openings 3 and 4. A connector 10 is in each case arranged at both openings 3 and 4 and can be sealed by means of a covering means 12 or connected directly to a preceding or succeeding container. This design of the purification device 1 is particularly advantageous, since simple and reliable installation of the purification device 1 within a production plant for liquid-crystal mixtures can be facilitated and rapid purification and subsequent filling of the liquid-crystal mixture can be carried out using the purification device 1.

(14) The purification method described above is particularly suitable for the purification of liquid-crystal mixtures. In particular, liquid-crystal mixtures comprising at least two organic substances, preferably mesogenic, in particular liquid-crystalline substances, are purified here using the device according to the invention, where the organic substances are preferably selected from the compounds of the general formula I,

(15) ##STR00001##
in which R.sup.1 and R.sup.2 each, independently of one another, denote H, an alkyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF.sub.3 or at least monosubstituted by halogen, where, in addition, one or more CH.sub.2 groups in these radicals may be replaced by O, S,

(16) ##STR00002##
CC, CHCH, CF.sub.2O, OCF.sub.2, OCO or OCO in such a way that O atoms are not linked directly to one another, and one of the radicals R.sup.1 and R.sup.2 also denotes F, Cl, CN, SF.sub.5, NCS, SCN, OCN, rings A, B, C, D and E each, independently of one another, denote

(17) ##STR00003## ##STR00004## ##STR00005## r, s and t each, independently of one another, denote 0, 1, 2 or 3, where r+s+t3, Z.sup.1-4 each, independently of one another, denote COO, OCO, CF.sub.2O, OCF.sub.2, CH.sub.2O, OCH.sub.2, CH.sub.2CH.sub.2, (CH.sub.2).sub.4, CHCHCH.sub.2O, C.sub.2F.sub.4, CH.sub.2CF.sub.2, CF.sub.2CH.sub.2, CFCF, CHCF, CFCH, CHCH, CC or a single bond, and L.sup.1 and L.sup.2 each, independently of one another, denote H or F.

(18) In the case where r+s+t=0, Z.sup.1 and Z.sup.4 are preferably selected in such a way that, if they do not denote a single bond, they are not linked to one another via two O atoms.

(19) The liquid-crystal mixtures to be purified comprising the individual mesogenic substances may additionally also comprise one or more polymerisable compounds, so-called reactive mesogens (RMs), for example as disclosed in U.S. Pat. No. 6,861,107, in concentrations of, preferably, 0.12-5% by weight, particularly preferably 0.2-2% by weight, based on the mixture. Mixtures of this type can be used for so-called polymer stabilised VA (PS-VA) modes, negative IPS (PS-IPS) or negative FFS (PS-FFS) modes, in which polymerisation of the reactive mesogens is intended to take place in the liquid-crystalline mixture. The prerequisite for this is that the liquid-crystal mixture does not itself comprise any individual polymerisable substances which likewise polymerise under the conditions where the reactive mesogens react.

(20) The polymerisable mesogenic or liquid-crystalline compounds, also known as reactive mesogens (RMs), are preferably selected from the compounds of the formula II
R.sup.a-A.sup.1-(Z.sup.1-A.sup.2).sub.m-R.sup.bII
in which the individual radicals have the following meanings: A.sup.1 and A.sup.2 each, independently of one another, denote an aromatic, heteroaromatic, alicyclic or heterocyclic group, preferably having 4 to 25 C atoms, which may also contain fused rings and which is optionally mono- or polysubstituted by L, Z.sup.1 on each occurrence, identically or differently, denotes O, S, CO, COO, OCO, OCOO, OCH.sub.2, CH.sub.2O, SCH.sub.2, CH.sub.2S, CF.sub.2O, OCF.sub.2, CF.sub.2S, SCF.sub.2, (CH.sub.2).sub.n, CF.sub.2CH.sub.2, CH.sub.2CF.sub.2, (CF.sub.2).sub.n, CHCH, CFCF, CC, CHCHCOO, OCOCHCH, CR.sup.0R.sup.00 or a single bond, L, R.sup.a and R.sup.b each, independently of one another, denote H, halogen, SF.sub.5, NO.sub.2, a carbon group or hydrocarbon group, where the compounds contain at least one radical L, R.sup.a and R.sup.b which denotes or contains a P-Sp- group, R.sup.0 and R.sup.00 each, independently of one another, denote H or alkyl having 1 to 12 C atoms, P denotes a polymerisable group, Sp denotes a spacer group or a single bond, m denotes 0, 1, 2, 3 or 4, n denotes 1, 2, 3 or 4.

(21) The polymerisable compounds may contain one polymerisable group (monoreactive) or two or more (di- or multireactive), preferably two, polymerisable groups.

(22) Above and below, the following meanings apply:

(23) The term mesogenic group is known to the person skilled in the art and is described in the literature, and denotes a group which, due to the anisotropy of its attracting and repelling interactions, essentially contributes to causing a liquid-crystal (LC) phase in low-molecular-weight or polymeric substances. Compounds containing mesogenic groups (mesogenic compounds) do not necessarily have to have an LC phase themselves. It is also possible for mesogenic compounds to exhibit LC phase behaviour only after mixing with other compounds and/or after polymerisation. Typical mesogenic groups are, for example, rigid rod- or disc-shaped units. An overview of the terms and definitions used in connection with mesogenic or LC compounds is given in Pure Appl. Chem. 73(5), 888 (2001) and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368.

(24) The term spacer group, also referred to as Sp above and below, is known to the person skilled in the art and is described in the literature, see, for example, Pure Appl. Chem. 73(5), 888 (2001) and C. Tschierske, G. Pelzl, S. Diele, Angew. Chem. 2004, 116, 6340-6368. Unless indicated otherwise, the term spacer group or spacer above and below denotes a flexible group which connects the mesogenic group and the polymerisable group(s) in a polymerisable mesogenic compound (RM) to one another. Sp preferably denotes a single bond or a 1-16 C alkylene, in which one or more CH.sub.2 groups may be replaced by O, CO, COO or OCO in such a way that two O atoms are not connected directly to one another.

(25) The term organic group denotes a carbon or hydrocarbon group.

(26) The term carbon group denotes a mono- or polyvalent organic group containing at least one carbon atom which either contains no further atoms (such as, for example, CC) or optionally contains one or more further atoms, such as, for example, N, O, S, P, Si, Se, As, Te or Ge (for example carbonyl, etc.). The term hydrocarbon group denotes a carbon group which additionally contains one or more H atoms and optionally one or more heteroatoms, such as, for example, N, O, S, P, Si, Se, As, Te or Ge.

(27) Halogen denotes F, Cl, Br or I.

(28) The terms alkyl, aryl, heteroaryl, etc., also encompass polyvalent groups, for example alkylene, arylene, heteroarylene, etc.

(29) The term alkyl in this application encompasses straight-chain and branched alkyl groups having 1 to 9 carbon atoms, preferably the straight-chain groups methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl and nonyl. Groups having 1 to 5 carbon atoms are particularly preferred.

(30) The term alkenyl in this application encompasses straight-chain and branched alkenyl groups having 2 to 9 carbon atoms, preferably the straight-chain groups having 2 to 7 carbon atoms. Particularly preferred alkenyl groups are C.sub.2-C.sub.7-1E-alkenyl, C.sub.4-C.sub.7-3E-alkenyl, C.sub.5-C.sub.7-4-alkenyl, C.sub.6-C.sub.7-5-alkenyl and C.sub.7-6-alkenyl, in particular C.sub.2-C.sub.7-1E-alkenyl, C.sub.4-C.sub.7-3E-alkenyl and C.sub.5-C.sub.7-4-alkenyl. Examples of preferred alkenyl groups are vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hex-enyl, 1E-hept-enyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl, 4Z-hexenyl, 4E-hexenyl, 4Z-hep-tenyl, 5-hexenyl, 6-heptenyl and the like. Groups having up to 5 carbon atoms are particularly preferred.

(31) The term fluoroalkyl in this application encompasses straight-chain groups having a terminal fluorine, i.e. fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 4-fluoro-butyl, 5-fluoro-pentyl, 6-fluorohexyl and 7-fluoroheptyl. However, other positions of the fluorine are not excluded.

(32) The term oxaalkyl or alkoxy in this application encompasses straight-chain radicals of the formula C.sub.nH.sub.2n+1O(CH.sub.2).sub.m, in which n and m each, independently of one another, denote 1 to 6. Preferably, n=1 and m=1 to 6.

(33) The term aryl denotes an aromatic carbon group or a group derived therefrom. The term heteroaryl denotes aryl in accordance with the above definition containing one or more heteroatoms.

(34) The polymerisable group P is a group which is suitable for a polymerisation reaction, such as, for example, free-radical or ionic chain polymerisation, polyaddition or polycondensation, or for a polymer-analogous reaction, for example addition or condensation onto a main polymer chain. Particular preference is given to groups for chain polymerisation, in particular those containing a CC double bond or a CC triple bond, and groups which are suitable for polymerisation with ring opening, such as, for example, oxetane or epoxide groups.

(35) The polymerisable compounds are prepared analogously to processes which are known to the person skilled in the art and are described in standard works of organic chemistry, such as, for example, in Houben-Weyl, Methoden der organischen Chemie [Methods of Organic Chemistry], Thieme-Verlag, Stuttgart.

(36) Typical and preferred reactive mesogens (RMs) are described, for example, in WO 93/22397, EP 0 261 712, DE 195 04 224, WO 95/22586, WO 97/00600, U.S. Pat. No. 5,518,652, U.S. Pat. No. 5,750,051, U.S. Pat. No. 5,770,107 and U.S. Pat. No. 6,514,578. Very particularly referred reactive mesogens are shown on Table E.

(37) The process is used for the preparation of a mixture consisting of organic compounds, one or more of which are preferably mesogenic, preferably liquid-crystalline, per se. The mesogenic compounds preferably include one or more liquid-crystalline compounds. The process product is preferably a homogeneous, liquid-crystalline mixture. In the broader sense, the process also encompasses the preparation of mixtures which consist of organic substances in the homogeneous liquid phase and comprise additives which are insoluble therein (for example small particles). The process can thus also be used for the preparation of suspension-like or emulsion-like mixtures based on a continuous homogeneous organic phase. However, process variants of this type are generally less preferred.

(38) By means of suitable additives, the liquid-crystal phases according to the invention can be modified in such a way that they can be employed in any type of LCD display that has been disclosed to date, for example, ECB, VAN, IPS, FFS, TN, TN-TFT, STN, OCB, GH, PS-IPS, PS-FFS, PS-VA or ASM-VA displays.

(39) The liquid-crystal mixtures may also comprise further additives known to the person skilled in the art and described in the literature, such as, for example, UV stabilisers, such as, for example, Tinuvin from Ciba, antioxidants, free-radical scavengers, nanoparticles, microparticles, one or more dopants, etc. For example, 0-15% of pleochroic dyes may be added, furthermore conductive salts, preferably ethyldimethyldodecylammonium 4-hexoxybenzoate, tetrabutylammonium tetraphenylboranate or complex salts of crown ethers (cf., for example, Haller et al., Mol. Cryst. Liq. Cryst. Volume 24, pages 249-258 (1973)) in order to improve the conductivity, or substances can be added in order to modify the dielectric anisotropy, the viscosity and/or the alignment of the nematic phases. Substances of this type are described, for example, in DE-A 22 09 127, 22 40 864, 23 21 632, 23 38 281, 24 50 088, 26 37 430 and 28 53 728.

(40) Suitable stabilisers and dopants which can be combined with the compounds of the formula I in the mixing container in the preparation of the liquid-crystal mixtures are indicated below in Tables C and D.

(41) In the present application and in the following examples, the structures of the liquid-crystal compounds are indicated by means of acronyms, with the transformation into chemical formulae taking place in accordance with Tables A and B below. All radicals C.sub.nH.sub.2n+1 and C.sub.mH.sub.2m+1 are straight-chain alkyl radicals having n and m C atoms respectively; n, m, k and z are integers and preferably denote 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 or 12. The term (O)C.sub.mH.sub.2m+1 means OC.sub.mH.sub.2m+1 or C.sub.mH.sub.2m+1. The coding in Table B is self-evident.

(42) In Table A, only the acronym for the parent structure is indicated. In individual cases, this is followed, separated from the acronym for the parent structure by a dash, by a code for the substituents R.sup.1*, R.sup.2*, L.sup.1* and L.sup.2*:

(43) TABLE-US-00001 Code for R.sup.1*, R.sup.2*, L.sup.1*, L.sup.2*, L.sup.3* R.sup.1* R.sup.2* L.sup.1* L.sup.2* nm C.sub.nH.sub.2n+1 C.sub.mH.sub.2m+1 H H nOm C.sub.nH.sub.2n+1 OC.sub.mH.sub.2m+1 H H nO.m OC.sub.nH.sub.2n+1 C.sub.mH.sub.2m+1 H H n C.sub.nH.sub.2n+1 CN H H nN.F C.sub.nH.sub.2n+1 CN F H nN.F.F C.sub.nH.sub.2n+1 CN F F nF C.sub.nH.sub.2n+1 F H H nCl C.sub.nH.sub.2n+1 Cl H H nOF OC.sub.nH.sub.2n+1 F H H nF.F C.sub.nH.sub.2n+1 F F H nF.F.F C.sub.nH.sub.2n+1 F F F nOCF.sub.3 C.sub.nH.sub.2n+1 OCF.sub.3 H H nOCF.sub.3.F C.sub.nH.sub.2n+1 OCF.sub.3 F H n-Vm C.sub.nH.sub.2n+1 CHCHC.sub.mH.sub.2m+1 H H nV-Vm C.sub.nH.sub.2n+1CHCH CHCHC.sub.mH.sub.2m+1 H H

(44) Preferred mesogenic or liquid-crystalline substances which are suitable for the preparation of liquid-crystal mixtures and can be used in the purification process according to the invention are listed, in particular, in Tables A and B:

(45) TABLE-US-00002 TABLE A 0 0

(46) TABLE-US-00003 TABLE B 0 0 0 0 0 0 0 00 01 02 03 04 05 06 07 08 09 0 0 0 0 0 0 0 0 0 00 01 02 03 04 05 06 07 08 09 0 0 0 (n = 1-15; (O)C.sub.nH.sub.2n+1 means C.sub.nH.sub.2n+1 or OC.sub.nH.sub.2n+1)

(47) Particular preference is given to liquid-crystalline mixtures which comprise at least one, two, three, four or more compounds from Table B besides one or more compounds of the formula I.

(48) TABLE-US-00004 TABLE C C 15 CB 15 CM 21 R/S-811 0 CM 44 CM 45 CM 47 CN R/S-2011 R/S-3011 R/S-4011 R/S-5011 R/S-1011

(49) Table C indicates possible dopants, which are generally added to the liquid-crystalline mixtures. The mixtures preferably comprise 0-10% by weight, in particular 0.01-5% by weight and particularly preferably 0.01-3% by weight, of dopants.

(50) TABLE-US-00005 TABLE D 0 0 0 0 (n = 1-12)

(51) Stabilisers, which can be added, for example, to the liquid-crystalline mixtures in amounts of 0-10% by weight, are shown below.

(52) Suitable polymerisable compounds (reactive mesogens) for use in the mixtures according to the invention, preferably in PSA and PS-VA applications or PS-IPS/FFS applications, are shown below in Table E:

(53) TABLE-US-00006 TABLE E RM-1 RM-2 RM-3 RM-4 0 RM-5 RM-6 RM-7 RM-8 RM-9 RM-10 RM-11 RM-12 RM-13 RM-14 00 RM-15 01 RM-16 02 RM-17 03 RM-18 04 RM-19 05 RM-20 06 RM-21 07 RM-22 08 RM-23 09 RM-24 0 RM-25 RM-26 RM-27 RM-28 RM-29 RM-30 RM-31 RM-32 RM-33 RM-34 0 RM-35 RM-36 RM-37 RM-38 RM-39 RM-40 RM-41 RM-42 RM-43 RM-44 0 RM-45 RM-46 RM-47 RM-48 RM-49 RM-50 RM-51 RM-52 RM-53 RM-54 0 RM-55 RM-56 RM-57 RM-58 RM-59 RM-60 RM-61 RM-62 RM-63 RM-64 0 RM-65 RM-66 RM-67 RM-68 RM-69 RM-70 RM-71 RM-72 RM-73 RM-74 0 RM-75 RM-76 RM-77 RM-78 RM-79 RM-80 RM-81 RM-82 RM-83 RM-84 0 RM-85 RM-86 RM-87 RM-88 RM-89 RM-90 RM-91 RM-92 RM-93 RM-94 0 RM-95

(54) Table E shows example compounds which can preferably be used as reactive mesogenic compounds in the liquid-crystalline mixtures according to the invention. If the liquid-crystalline mixtures comprise one or more reactive compounds, they are preferably employed in amounts of 0.01-5% by weight. It may be necessary also to add an initiator or a mixture of two or more initiators for the polymerisation. The initiator or the initiator mixture is preferably added in amounts of 0.001-2% by weight, based on the mixture. A suitable initiator is, for example, Irgacure (BASF) or Irganox (BASF).

(55) In a preferred embodiment, the liquid-crystalline mixtures comprise one or more compounds selected from the group of the compounds from Table E.

EXAMPLES

(56) The following working examples are intended to explain the invention without restricting it.

(57) Above and below, percent data denote percent by weight. All temperatures are indicated in degrees Celsius. m.p. denotes melting point, cl.p.=clearing point. Furthermore, C=crystalline state, N=nematic phase, S=smectic phase and I=isotropic phase. The data between these symbols represent the transition temperatures. Furthermore, V.sub.o denotes threshold voltage, capacitive [V] at 20 C. n denotes the optical anisotropy measured at 20 C. and 589 nm denotes the dielectric anisotropy at 20 C. and 1 kHz cl.p. denotes clearing point [ C.] K.sub.1 denotes elastic constant, splay deformation at 20 C., [pN] K.sub.3 denotes elastic constant, bend deformation at 20 C., [pN] .sub.1 denotes rotational viscosity measured at 20 C. [mPa.Math.s], determined by the rotation method in a magnetic field LTS denotes low-temperature stability (nematic phase), determined in test cells.

(58) The following examples are intended to explain the invention without limiting it.

Working Examples

Example 1

(59) A liquid-crystalline mixture of the composition

(60) TABLE-US-00007 CCH-35 9.47% CCH-501 4.99% CCY-2-1 9.47% CCY-3-1 10.47% CCY-3-O2 10.47% CCY-5-O2 9.47% CPY-2-O2 11.96% CY-3-O4 8.97% CY-5-O4 10.97% RM-1 0.30% PCH-53 13.46%
is purified as follows using the purification device depicted in FIG. 1:

(61) The mixture with a batch size of 350 kg is treated with 10 kg of aluminium oxide (Merck KGaA, pore size 6-15 m, particle size 60-200 m) and with 6 kg of zeolites (Merck KGaA, particle size 150-350 m). For a batch size of 200 g, 4 g of aluminium oxide and 1.5 g of zeolites are used.

(62) The purified LC mixture in accordance with Example 1 is preferably suitable for PS-VA applications.

Example 2

(63) TABLE-US-00008 BCH-32 7.48% CCH-23 21.93% CCH-34 3.49% CCY-3-O3 6.98% CCY-4-O2 7.98% CPY-2-O2 10.97% CPY-3-O2 10.97% CY-3-O2 15.45% RM-1 0.30% PCH-301 12.46% PCH-302 1.99%

(64) The LC mixture in accordance with Example 2 is treated analogously to Example 1 with 4.5 kg of aluminium oxide (Merck KGaA, pore size 6-15 m, particle size 60-200 m) and with 2.5 kg of silica gel (Merck KGaA, particle size 40-100 m) with a batch size of 100 kg.

(65) The purified mixture in accordance with Example 2 is preferably suitable for PS-VA applications.

Example 3

(66) TABLE-US-00009 CC-3-V1 7.98% CCH-23 17.95% CCH-34 3.99% CCH-35 6.98% CCP-3-1 4.99% CCY-3-O2 12.46% CPY-2-O2 7.98% CPY-3-O2 10.97% CY-3-O2 15.45% RM-1 0.30% PY-3-O2 10.97%

(67) This mixture is treated analogously to Example 1 with 2.8 kg of aluminium oxide (Merck KGaA, pore size 6-15 m, particle size 60-200 m) and with 1.7 kg of zeolites (Merck KGaA, particle size 150-350 m) with a batch size of 100 kg. For a batch size of 1000 g, 27 g of aluminium oxide and 14 g of zeolites are used.

(68) The LC mixture in accordance with Example 3 is preferably suitable for PS-VA applications.

Example 4

(69) TABLE-US-00010 CC-3-V1 8.97% CCH-23 12.96% CCH-34 6.23% CCH-35 7.73% CCP-3-1 3.49% CCY-3-O2 12.21% CPY-2-O2 6.73% CPY-3-O2 11.96% CY-3-O2 11.47% RM-1 0.30% PP-1-2V1 4.24% PY-3-O2 13.71%

(70) This mixture is treated analogously to Example 1 with 1.7 kg of magnesium silicate (Merck KGaA, particle size 150-250 m) and with 1.1 kg of silica gel (Merck KGaA, particle size 63-100 m) with a batch size of 85 kg. For a batch size of 500 g, 10 g of aluminium oxide and 4.6 g of silica gel are used.

(71) The LC mixture in accordance with Example 4 is preferably suitable for PS-VA applications.

Example 5

(72) TABLE-US-00011 CBC-33 3.50% CC-3-V 38.00% CC-3-V1 10.00% CCP-V-1 3.00% CCP-V2-1 9.00% PGP-2-3 5.00% PGP-2-4 5.00% PGU-2-F 8.00% PGU-3-F 9.00% PUQU-3-F 9.50%

(73) This mixture is treated analogously to Example 1 with 2.1 kg of silica gel (Merck KGaA, particle size 60-200 m) and with 0.9 kg of zeolites (Merck KGaA, particle size 150-350 urn) with a batch size of 56 kg. For a batch size of 400 g, 20 g of silica gel and 9 g of zeolites are used.

(74) The LC mixture in accordance with Example 5 is preferably suitable for TN-TFT applications.

Example 6

(75) TABLE-US-00012 APUQU-3-F 4.50% CC-3-V 44.00% CC-3-V1 12.00% CCP-V-1 11.00% CCP-V2-1 9.00% PGP-2-3 6.00% PGUQU-3-F 6.00% PP-1-2V1 7.00% PPGU-3-F 0.50%

(76) This mixture is treated analogously to Example 1 with 890 g of zeolites (Merck KGaA, particle size 150-350 m) with a batch size of 29 kg. For a batch size of 300 g, 5.7 g of zeolites are used.

(77) The LC mixture in accordance with Example 6 is preferably suitable for IPS or FFS applications.

Example 7

(78) TABLE-US-00013 APUQU-3-F 8.00% CBC-33 3.00% CC-3-V 34.00% CC-3-V1 2.50% CCGU-3-F 4.00% CCP-30CF.sub.3 4.00% CCP-3F.F.F 4.50% CCP-50CF.sub.3 3.00% CCP-V-1 10.00% CCQU-3-F 10.00% CPGU-3-OT 6.00% PGUQU-3-F 4.00% PUQU-3-F 7.00%

(79) A batch size of 265 kg of this mixture is treated analogously to Example 1 with 10.6 kg of aluminium oxide (Merck KGaA, pore size 6-10 m, particle size 40-200 m).

(80) The LC mixture in accordance with Example 7 is preferably suitable for IPS or FFS applications.

Example 8

(81) TABLE-US-00014 APUQU-2-F 5.00% APUQU-3-F 7.50% BCH-3F.F.F 7.00% CC-3-V 40.50% CC-3-V1 6.00% CCP-V-1 9.50% CPGU-3-OT 5.00% PGP-2-3 6.00% PGP-2-4 6.00% PPGU-3-F 0.50% PUQU-3-F 7.00%

(82) A batch size of 530 kg of this mixture is firstly purified analogously to Example 1 using 10.6 kg of silica gel RP8 (Merck KGaA, pore size 6-30 m, particle size 10-40 m). In addition, 4.3 kg of zeolites (Merck) are required for the subsequent treatment.

(83) The LC mixture in accordance with Example 8 is preferably suitable for IPS or FFS applications.

Example 9

(84) TABLE-US-00015 APUQU-2-F 8.00% APUQU-3-F 8.00% BCH-32 7.00% CC-3-V 43.00% CCP-V-1 9.00% PGP-2-3 7.00% PGP-2-4 6.00% PUQU-2-F 5.00% PUQU-3-F 7.00%

(85) This mixture is purified analogously to Example 1 using 15 g of aluminium oxide (Merck KGaA, particle size 40-63 m) with a batch size of 3 kg. For a batch size of 100 kg, 4.3 kg of aluminium oxide and 1.7 kg of zeolites (Grace, particle size 100-500 m) are used.

(86) The LC mixture in accordance with Example 9 is preferably suitable for TN-TFT applications.

Example 10

(87) TABLE-US-00016 BCH-5F.F 8.00% CBC-33F 3.00% CC-3-V 22.00% CCGU-3-F 6.00% CCP-3F.F.F 8.00% CCP-5F.F.F 4.00% CCP-V-1 13.00% CCP-V2-1 11.00% CCQU-3-F 5.00% CCQU-5-F 4.00% PUQU-3-F 16.00%

(88) A batch size of 530 kg of this mixture is purified analogously to Example 1 using 10.6 kg of silica gel RP8 (Merck KGaA, pore size 6-30 m, particle size 10-40 m). In addition, 4.3 kg of zeolites (Merck KGaA, particle size 150-350 m) are required for the subsequent treatment.

(89) The LC mixture in accordance with Example 10 is preferably suitable for TN-TFT applications.

Example 11

(90) TABLE-US-00017 CBC-33F 3.00% CBC-53F 3.00% CC-3-V 17.00% CC-3-V1 4.00% CCP-3F.F.F 8.00% CCPC-33 3.00% CCPC-34 3.00% CCP-V-1 5.00% CCP-V2-1 2.00% CCQU-2-F 1.50% CCQU-3-F 10.00% CCQU-5-F 10.00% CGU-3-F 6.00% PGP-2-3 7.50% PP-1-2V1 7.00% PUQU-3-F 10.00%

(91) A batch size of 3 kg of this mixture is purified analogously to Example 1 using 147 g of silica gel RP4 (Merck KGaA, pore size 6-30 m, particle size 10-40 m).

(92) The LC mixture in accordance with Example 11 is preferably suitable for TN-TFT applications.

Example 12

(93) TABLE-US-00018 APUQU-2-F 1.00% BCH-3F.F.F 15.00% CC-3-V 33.50% CC-3-V1 2.00% CCGU-3-F 1.00% CCPC-33 2.00% CCP-V-1 4.50% BCH-2F 5.00% BCH-3F 5.00% PGP-2-3 8.50% PGUQU-3-F 7.80% PP-1-2V1 11.00% PPGU-3-F 0.20% PUQU-3-F 3.50%

(94) A batch size of 143 kg of this mixture is purified analogously to Example 1 using 715 g of magnesium silicate (Merck KGaA, particle size 150-250 m).

(95) The LC mixture in accordance with Example 12 is preferably suitable for TN-TFT applications.

Example 13

(96) TABLE-US-00019 APUQU-2-F 2.00% APUQU-3-F 6.00% CC-3-V 42.00% CCP-3-1 3.00% CCP-3-3 3.00% CCP-3F.F.F 8.00% CCP-V-1 1.50% CCQU-3-F 7.00% CCQU-5-F 3.00% CPGU-3-OT 6.50% PGUQU-3-F 5.00% PGUQU-4-F 4.00% PGUQU-5-F 4.00% PPGU-3-F 0.50% PUQU-3-F 4.50%

(97) This mixture is treated analogously to Example 1 with 212 g of aluminium oxide (Merck KGaA, particle size 63-200 m) with a batch size of 3 kg. In addition, 100 g of zeolites (Merck KGaA, particle size 150-350 m) are used.

(98) The LC mixture in accordance with Example 13 is preferably suitable for IPS or FFS applications.

Example 14

(99) TABLE-US-00020 CC-3-V 49.50% CCP-3-1 1.50% CCP-V-1 6.00% CPGU-3-OT 7.00% PGP-2-3 8.50% PGP-2-4 5.50% PGUQU-3-F 7.00% PGUQU-4-F 4.00% PP-1-2V1 2.50% PPGU-3-F 0.50% PUQU-3-F 8.00%

(100) This mixture is treated with 106 g of aluminium oxide (Merck, pore size 6-15 m, particle size 40-63 m) and with 40 g of silica gel (Merck KGaA, particle size 63-100 m) with a batch size of 1.5 kg. For a batch size of 24 kg, 1.6 kg of aluminium oxide and 0.8 kg of silica gel are used.

(101) The LC mixture in accordance with Example 14 is preferably suitable for TN-TFT applications.

Example 15

(102) TABLE-US-00021 BCH-32 6.00% CCH-23 18.00% CCH-34 8.00% CCP-3-1 12.00% CCP-3-3 3.00% CCY-3-O2 6.00% CPY-2-O2 6.00% CPY-3-O2 7.00% CY-3-O2 14.00% CY-3-O4 8.00% CY-5-O2 9.00% PYP-2-3 3.00%

(103) A batch size of 16 kg of this mixture is purified analogously to Example 1 using 460 g of silica gel RP8 (Merck KGaA, pore size 6-30 m, particle size 10-40 m).

(104) The LC mixture in accordance with Example 15 is preferably suitable for VA applications.

Example 16

(105) TABLE-US-00022 CC-3-V1 7.98% CCH-23 17.95% CCH-34 3.99% CCH-35 6.98% CCP-3-1 4.99% CCY-3-O2 12.46% CPY-2-O2 7.98% CPY-3-O2 10.97% CY-3-O2 15.45% RM-17 0.30% PY-3-O2 10.97%

(106) This mixture is treated analogously to Example 1 with 2.6 kg of aluminium oxide (Merck KGaA, pore size 6-15 m, particle size 63-200 m) and with 1 kg of silica gel (Merck KGaA, particle size 63-100 m) with a batch size of 132 kg. For a batch size of 500 kg, 16 kg of aluminium oxide and 8 kg of silica gel are used.

(107) The LC mixture in accordance with Example 16 is preferably suitable for PS-VA and PS-FFS applications.

Example 17

(108) TABLE-US-00023 CC-3-V 29.50% PP-1-3 11.00% PY-3-O2 12.00% CCP-3-1 9.50% CCOY-2-O2 18.00% CCOY-3-O2 13.00% GPP-5-2 7.00%

(109) This mixture is treated analogously to Example 1 with 53 g of magnesium silicate (Merck KGaA, particle size 150-250 m) for a batch size of 1 kg.

(110) The LC mixture in accordance with Example 17 is preferably suitable for VA applications.

Example 18

(111) TABLE-US-00024 PY-V2-O2 12.00% CY-V-O2 9.00% CCY-3-O1 9.00% CCY-V2-O2 8.00% CCY-2-O2 8.00% CPY-V-O2 10.50% CC-3-V 36.50% BCH-32 6.50% PPGU-3-F 0.50%

(112) A batch size of 16 kg of this mixture is purified analogously to Example 1 using 460 g of silica gel RP8 (Merck KGaA, pore size 6-30 m, particle size 10-40 m).

(113) The LC mixture in accordance with Example 18 is preferably suitable for VA applications.

(114) Mixture Examples 1 to 18 may additionally also comprise one or more stabilisers, preferably one or two, and a dopant from Tables C and D.