Filling device and use thereof for dispensing a fluid

The invention describes a filling device for dispensing a fluid, in particular a liquid-crystal mixture, into at least one container, and the use thereof for dispensing a liquid-crystal mixture.

Various filling devices or filling machines are known by means of which a meterable amount of fluid can be introduced into a container. The fluid can be, for example, liquid or flowable chemical raw materials or end products which are used in the chemical or pharmaceutical industry. The fluid may also be a liquid food or a liquid component for the preparation of foods.

The fluid can be introduced into the container by means of a filling-needle system. Reliable metering during the filling operation can be ensured via a weighing system.

Suitable containers which are employed in the context of industrial use are usually drums, canisters or bottles which are made from plastic, metal or glass. Containers of this type serve for the transport or storage of the liquid introduced into the container. So-called rotary machines, for example, are known here, in which small containers to be filled are automatically fed into a rotating conveyor device and filled with the desired liquid or the pre-specified fluid in the filling machine.

The fluids are usually pumped into the container to be filled from a fluid reservoir, for example from a further container, by means of a pump. The containers to be filled may differ here with respect to their size and shape, meaning that adaptation of the filling machine to the container to be filled in the individual case is regularly necessary. It is regarded as disadvantageous here that each change in the container size requires re-fitting of the filling device.

It is known from practice that a filling nozzle of the filling device which is used for filling the containers can be displaced axially and is moved out or in depending on the container size. The length of the section projecting into the container can be changed and adapted to respective other container sizes. In spite of the possibility of adjustment for the length of the filling nozzle, the use of a filling machine of this type is restricted, since calibration of the filling speed has to be carried out and in addition the containers have to be positioned manually. For containers which have a different diameter of the opening intended for the introduction of the liquid, either the container position must be pre-specified separately, giving rise to an additional handling operation, or alternatively a separate filling machine adapted to the containers in question must be used.

Particularly in the case of the dispensing of liquid-crystal mixtures, high demands are made of the filling machine or of the filling operation, such as, for example, clean-room ambient conditions. Before the filling of the containers with liquid-crystal mixtures, the containers to be filled generally have to be inertised, which is usually carried out before arrangement of the containers in a filling position and is subsequently followed by displacement of the containers from an inertisation position to the filling position.

It is therefore regarded as an object of the present invention to design a filling machine for dispensing liquids into a container in such a way that the filling machine can be adapted to different containers with as little effort as possible and optionally offers possibilities for inertisation.

This object is achieved in accordance with the invention in that a filling device for dispensing a fluid into at least one container is provided, where the filling device has at least one weighing system and a filling-needle system, where the weighing system has at least one container positioning device which can be adapted to a container diameter, where the weighing system is arranged on an accommodation platform which can be moved vertically by means of a linear unit and where the filling-needle system is arranged on a displacement unit in a position at a distance in the axial direction above the positioning device.

For the purposes of the present invention, the term fluid is taken to mean all flowable inorganic, organic or biological systems or mixtures, for example true or colloidal solutions, suspensions, emulsions, melts, dispersions, liquid/gas dispersions or mixtures thereof. In particular, liquid-crystalline mixtures and isotropic liquid mixtures are taken to be fluids in the sense of the invention.

The filling device can advantageously be used for dispensing a liquid-crystal mixture into at least one container, where the filling is preferably carried out in a clean room. Owing to its advantageous design, the device is suitable for use in clean rooms. This has proven extremely positive, since the filling-device design according to the invention means that it is not necessary to re-fit the filling device in the case of a change of the containers, enabling costs and work to be saved. In particular, the possibility that inertisation and filling of a container can be carried out using the filling device without major manual interventions or displacement of the container or a complex re-fitting operation being necessary has proven advantageous for use of the filling device, in particular in a clean room. In addition, the high quality and purity of the dispensed fluid can be retained, in particular in the case of a liquid-crystal mixture.

A filling device is provided by means of which high filling accuracy is achieved. The filling operation can be monitored by a high-precision balance. The weighing system containing the balance has at least one positioning device, preferably with an annular design, for at least one container. This enables not only weighing of the empty container, but also monitoring of the filling operation itself and the amount of fluid metered in during the filling operation. During the filling operation, the volume flow of the liquid to be introduced is preferably monitored at specifiable intervals by a process computer integrated into the weighing system, and this actual value determined is compared with a nominal value. The volume flow can be increased or reduced manually or automatically if necessary. The change in the volume flow can take place via a membrane valve installed upstream of the filling-needle system. Other adjustable or controllable valves are also conceivable.

In a preferred embodiment of the device, an operator unit, for example a touch-screen monitor with a reader, is connected to the filling device. Via the reader, which is designed, for example, as a barcode scanner, information or a barcode on a container to be filled or on a storage container of the fluid to be dispensed can be input. This information is compared with a database, after which adjustments specific to the filling operation, i.e. specific to the container or specific to the product, can be carried out automatically on the filling device, so that an individual filling operation can be guaranteed for different fluids or for different containers.

In order to facilitate adaptation to the different container sizes or drum sizes, the weighing system with the positioning device is arranged on an accommodation platform which can be moved vertically by means of a linear unit, so that the position of the weighing system and thus of the container relative to the filling-needle system can be adjusted depending on the container to be filled, i.e. depending on its volume or size. The accommodation platform is moved automatically to the height required for the filling of the container by a machine control system of the linear unit. Additional detection of the empty container via the tare weight can prevent malfunctions of the filling device.

It may also be advantageous for the filling device to comprise two or more weighing systems, where the weighing systems are each arranged on a separate accommodation platform which can be moved vertically by means of in each case one linear unit. The accommodation tables can be controlled separately, enabling two containers, in particular two containers of different size, to be filled simultaneously by means of the filling device.

It is likewise possible and advantageous for certain applications to arrange two or more weighing systems on a common accommodation platform, if the filling device is used predominantly for the filling of a single container size.

In a particularly advantageous embodiment, the filling device has two weighing systems, where the two weighing systems are each mounted on an accommodation platform which can be moved vertically by means of in each case one linear unit.

The weighing system preferably has at least one container positioning device with an annular design. In the case of two weighing systems or more, it is advantageously provided that each weighing system with in each case one positioning device is arranged on the at least one movable accommodation platform. The weighing system may in addition have a universal positioning device, by means of which the containers can be reliably centred and positioned. This has proven advantageous, since this enables the filling needle to be positioned reproducibly in the opening of the containers. This universal adaptation ability of the positioning device is provided through the positioning device consisting of a plurality of annular bulges and each bulge being intended or standardised for a defined container size. Clamping means may also be utilised for positioning of the containers.

The containers which are particularly suitable for use with the filling device are glass bottles in the sizes 0.1-0.5 l and 1 l, and steel containers in the size 10 l. This adaptation ability of the positioning device guarantees universal usability of the device and is to be regarded as an essential advantage over the filling devices known in the prior art. The filling device can of course be extended at any time with further positioning devices which are standardised to further container sizes. The positioning devices can advantageously be fixed on or to the weighing system by means of a non-positive or positive connection, enabling fast replacement.

It has proven advantageous if the filling device, in particular the weighing system and the volume flow, can be matched to the liquid to be dispensed and the containers. This enables product-specific filling through adaptation of the filling parameters via software of the device control system. Differing properties of the fluids, in particular different liquid-crystal mixtures, also require different filling parameters. The optimum filling parameters can be determined in advance in a suitable manner in experiments and saved in a database. During initialisation of the device, the product-specific data can be read in via an input device or reader, for example a barcode reader, and identified from a barcode on the documents accompanying the batch. Fine adjustment of the parameters may in addition also be possible by hand.

Furthermore, it is advantageous to use a pump, whose control can be taken on by the filling device. The corresponding parameters are preferably called up via the database, and, for example, the volume flow is regulated correspondingly. The filling device may also advantageously ensure pressure regulation of a storage container and thus media transport.

The filling-needle system is preferably arranged on a horizontally movable displacement unit at a distance in the axial direction above the positioning device. The filling is preferably carried out under software control in the steps coarse, medium and fine flow. This enables the duration of the filling operation to be minimised.

According to an advantageous embodiment of the inventive idea, it is provided that the filling-needle system comprises a combined filling and inertisation needle. In addition, the diameters of the combined filling and inertisation needles may have been optimised in experiments with respect to the filling flow to be expected. Before the filling, the container is preferably inertised by means of a noble gas.

For this purpose, the filling-needle system may, in addition to the filling needle, have a second tube welded on at the side or, in another embodiment, a tube mounted coaxially over the filling needle. This tube is likewise called a needle in the sense of the invention. This means that the filling-needle system preferably comprises a first needle for the inertisation and a second needle for the filling. The combination of an inertisation needle and a filling needle enables the inertisation and filling operation to be carried out in one position, namely in the filling device according to the invention, without displacement of the container being necessary. The inertisation tube or the inertisation needle may advantageously be somewhat tapered in a front region in order to facilitate introduction of the needle into glass bottles having narrow mouths.

In a preferred embodiment of the device, the filling-needle system is arranged in a clamping block which can be removed from the displacement unit. The entire filling-needle system is preferably mounted in a clamping block and can thus be prepared and assembled outside the device. The clamping block can be mounted on and fixed to the displacement unit using attachment means known to the person skilled in the art, in particular screws. The filling-needle system is preferably installed in the clamping block using clamp connections, in particular in accordance with DIN standards 32676, 11851, 11864 and 11853. This guarantees rapid assembly and disassembly.

Components of the filling-needle system which may come into contact with the respective fluid used during the filling operation preferably consist of stainless steel and/or polytetrafluoroethylene (PTFE). However, it may likewise be advantageous, depending on the proposed application, to use other metals or plastics. Plastics denote, in particular, materials whose essential constituents consist of macromolecular organic compounds which are formed synthetically or by modification of natural products. The plastics also include, in particular, the rubbers and the synthetic fibres. For the advantageous embodiment, use can be made of plastics from the group modified natural products, synthetic plastics (polycondensates, polymers, polyaddition products), thermosets and/or unsaturated polyester resins, including cellulose nitrate, cellulose acetate, cellulose mixed esters, cellulose ethers, polyamide, polycarbonate, polyester, polyphenylene oxide, polysulfone, polyvinylacetal, polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ionomers, polyvinyl chloride, polyvinylidene chloride, polymethyl methacrylate, polyacrylonitrile, polystyrene, polyacetal, fluorinated plastics, polyvinyl alcohol, polyvinyl acetate, poly-p-xylylene, linear polyurethanes, chlorinated polyethers, casein plastics, crosslinked polyurethanes, silicone, polyimide and/or polybenzimidazole.

It may furthermore be advantageous for the components of the filling-needle system to be made from metal, in particular from stainless steel. Stainless steel is resistant to water, water vapour, atmospheric moisture, edible acids and to weak organic and inorganic acids and offers the filling needle good protection against many different fluids. It may of course also be advantageous to make the filling-needle system from a combination of metal and plastic.

The clamping block of the filling-needle system is attached to the displacement unit, where the displacement unit and in particular the clamping block can be moved at least horizontally for fine adjustment by means of suitable means. This enables slight inaccuracies of the needle geometry of different needles to be compensated. The adjustment can advantageously be carried out by hand using adjustment screws, so that fine adjustment in the direction of the X and Z axes of the filling-needle system is possible.

In a preferred embodiment, the filling device has a drop-catching system, where the drop-catching system, which is attached to a swivel arm and includes a vessel, can be swivelled beneath the filling-needle system if no container is located in the positioning device or the filling operation is complete. Dripping of liquid, in particular liquid-crystal mixture, out of the filling needle onto the weighing system can thus be prevented.

The filling needle is optimised with respect to its dimensions so that it preferably projects into the opening of the container. In order to prevent dripping of liquid out of the filling-needle system in a filling-needle design of this type too, a drop-catching system adapted thereto may be integrated. It consists, in particular, of a vessel, in particular a collection vessel, which is mounted on a swivel arm, which can be moved beneath the filling-needle system automatically or manually after the filling operation, i.e. as soon as the filling operation is complete or no container is located in the positioning device of the weighing system, the vessel can be swivelled beneath the filling-needle system. This enables dripping of liquid onto the weighing system to be reliably prevented.

A filter unit for filtration of the fluid to be dispensed is advantageously installed upstream of the membrane valve used to control the volume flow. Before the filling, all the liquid to be dispensed is preferably filtered through a filter unit. A filter unit of this type can, for example, be mounted on the side of the device in a corresponding filter holder and may include an ultrafine filter. The filter is preferably attached to a quick-change filter holder in a readily accessible manner. It can advantageously be prepared before attachment and subsequently mounted on the filter holder, preferably via a clamp connection.

In order to prevent undesired effects due to electrostatic charging of the liquid, in particular the liquid-crystal mixture, during the filling operation, ionisers are in a preferred embodiment of the device installed laterally, above and/or below the filling-needle system and emit a directed stream of ionised air against the filling-needle system and/or the filling region. This enables, in particular, effects such as a liquid-crystal mixture flowing past the opening or mouth of the container to be filled due to electrostatic charging to be substantially prevented.

It may furthermore be advantageous for protective walls having an antistatic coating to be arranged laterally to the filling-needle system. The protective walls are preferably earthed. The protective walls enable any interfering electrostatic effects otherwise possibly occurring owing to the laminar flow of the fluid to be dispensed to be reduced or even entirely prevented.

In the following list, various features and advantages of the filling device according to the invention are summarised:

- high filling accuracy (in particular −0%/+0.3 −0.03%);
- high filling speed including inertisation of the container, in particular 0.5 l in 30 seconds;
- use of glass bottles of different dimensions and in particular 10 l containers on one device possible;
- filling-needle system which is easy to disassemble and clean;
- inertisation of the containers before filling;
- filtration of the filling medium, in particular the liquid, before filling;
- fine adjustment of the filling-needle system via the displacement unit possible;
- integrated ionisers for ionisation of the filling point in order to reduce electrostatic effects;
- drop-catching system for preventing contamination and incorrect measurements of the device by dripping liquid, in particular liquid-crystal mixture;
- product-specific filling by adaptation of the filling parameters via the software of the device control system.

Further advantageous embodiments are explained in greater detail with reference to an illustrative embodiment depicted in the drawing, in which:

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an illustrative depiction of a filling device according to the invention, and

FIG. 2 shows an illustrative depiction of a filling-needle system for the filling device shown in FIG. 1.

FIG. 1 shows a diagrammatic representation of a preferred filling device 1. The filling device 1 comprises two separate weighing systems 2, two filling-needle systems 3, two positioning devices 4 which can be adapted to a container diameter, and two drop-catching systems 5.

The container positioning device 4 has an annular design and has bulges of different size, so that containers having different sizes or diameters can be introduced and fixed reliably in the respective positioning device.

In order to enable the two weighing systems 2 to be moved vertically, the two weighing systems 2 are arranged on an accommodation platform 7 which can be moved vertically by means of a linear unit 6. The two weighing systems 2 can be adapted uniformly to different container sizes by means of the common accommodation platform 7, where automatic or manual displacement of the accommodation platform 7 can take place.

In the case where a plurality of containers of different size are to be filled independently of one another and if possible simultaneously with one or more fluids, each weighing system 2 could, contrary to the illustrative variant depicted by way of example, be arranged on an assigned accommodation platform 7 each, where the accommodation tables 7 can be moved vertically independently of one another by means of in each case one linear unit 6. This enables the accommodation tables 7 to be moved into different positions, enabling the filling of different container sizes.

The filling-needle systems 3 are each arranged in a position at a distance in the axial direction above the positioning devices 4 on a displacement unit 8 which can be moved horizontally. This enables each filling-needle system 3 and the assigned weighing system 2 to be adapted to different container sizes. The adjustment of the filling-needle system 3 takes place via a fine adjustment which enables horizontal displacement of the system 3 in the X and Z directions. Simultaneous horizontal and vertical movability of the filling-needle system 3 may optionally also be provided. It has been found that this enables it to be ensured that the filling-needle system 3 penetrates to an optimum extent into the opening of a container and efficient and lossfree filling is possible.

In order to prevent fluid residues dripping out of the filling-needle system 3 onto the weighing system 2 after filling of a container, the drop-catching system 5, which is attached to a swivel arm and includes a vessel, can advantageously be swivelled beneath the associated filling-needle system 3 after filling. It can thus be ensured that the weighing system 2 is not contaminated by fluid residues and the weighing of a current or future filling operation is thereby falsified. The drop-catching system 5 may of course also be designed in such a way that it swivels automatically beneath the filling-needle system 3 as soon as or if no container is located in the positioning device 4.

Before filling of a container located in the positioning device 4, the fluid to be dispensed is advantageously purified using a filter unit 9. The filter unit 9, preferably an ultrafine filter, can be mounted on the side of the filling device 1 in a filter holder 10. The filter unit 9 can be prepared before beginning the filling and inserted rapidly into the filter holder 10, in particular via clamp connections.

Different properties of the fluids and in particular liquid-crystal mixtures to be dispensed require adaptation of the filling to the differing properties of the fluids in question. The specific filling parameters, such as, for example, adjustment of the weighing system, the container size, a filling speed and optionally ionisation, can be determined in advance and stored in a database. During initialisation of the filling device, these parameters can be input into the filling device 1, for example via a touch-screen monitor 11. The filling device 1 subsequently automatically adjusts all relevant parameters correspondingly. However, it may also be advantageous for the product-specific data to be input via a reader, for example a barcode reader (not depicted), from a barcode on documents accompanying the batch, on containers to be filled or on a storage container of the fluid to be dispensed. The barcode reader can thus be an advantageous supplement of the filling device 1 and may be connected, for example, to the touch-screen monitor 11. The filling device 1 is arranged in a switching cabinet 15, which also accommodates circuitry of supply and discharge lines of the filling device 1.

Side walls 16 which have an antistatic coating may be arranged laterally alongside the weighing systems 2 or alongside the filling-needle systems 3, so that electrostatic charges formed by a laminar flow of the liquid to be dispensed are prevented.

FIG. 2 shows an enlarged representation of the filling-needle system 3. The filling-needle system 3 comprises a combined filling and inertisation needle 12. Filling and inertisation of a container are thus possible using the filling-needle system 3 of the filling device without the container having to be transported to a further station for this purpose.

The filling-needle system 3 is fixed in a clamping block 13 and may be assembled outside the filling device 1. The clamping block 13 can be mounted on the displacement unit (not depicted in FIG. 2) using attachment means, for example screws. The installation of the filling-needle system 3 in the clamping block 13 is carried out in an advantageous manner by means of clamp connections, enabling rapid assembly and disassembly. The filling-needle system 3 may furthermore have screws 14 for the fine adjustment of the filling-needle system 3 on the displacement unit, so that the position of the combined filling and inertisation needle 12 in the opening of a container is achieved. The fine adjustment preferably enables the filling-needle system 3 and/or the clamping block 13 to be moved horizontally and/or vertically on the displacement unit.

The filling device described above is particularly suitable for liquid-crystal mixtures. In particular, liquid-crystal mixtures comprising at least two organic substances, preferably mesogenic, in particular liquid-crystalline substances, are used here, where the organic substances are preferably selected from the compounds of the general formula I,

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in which

R¹and R²each, independently of one another, denote H, an alkyl radical having up to 15 C atoms which is unsubstituted, monosubstituted by CN or CF₃or at least monosubstituted by halogen, where, in addition, one or more CH₂groups in these radicals may be replaced by —O—, —S—,

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—C≡C—, —CH═CH—, —CF₂O—, —OCF₂—, —OC—O— or —O—CO— in such a way that 0 atoms are not linked directly to one another, and one of the radicals R¹and R²also denotes F, Cl, CN, SF₅, NCS, SCN, OCN,

rings A, B, C, D and E each, independently of one another, denote

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r, s and t each, independently of one another, denote 0, 1, 2 or 3, where r+s+t≤3,

Z^1-4each, independently of one another, denote —CO—O—, —O—CO—, —CF₂O—, —OCF₂—, —CH₂O—, —OCH₂—, —CH₂CH₂—, —(CH₂)₄—, —CH═CH—CH₂O—, —C₂F₄—, —CH₂CF₂—, —CF₂CH₂—, —CF═CF—, —CH═CF—, —CF═CH—, —CH═CH—, —C≡C— or a single bond, and

L¹and L²each, independently of one another, denote H or F.

In the case where r+s+t=0, Z¹and Z⁴are 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.

The liquid-crystal mixtures employed 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.

The polymerisable mesogenic or liquid-crystalline compounds, also known as “reactive mesogens” (RMs), are preferably selected from the compounds of the formula II

R^a-A¹-(Z¹-A²)_m-R^b II

in which the individual radicals have the following meanings:

A¹and A²each, 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,
Z¹on each occurrence, identically or differently, denotes —O—, —S—, —CO—, —CO—O—, —OCO—, —O—CO—O—, —OCH₂—, —CH₂O—, —SCH₂—, —CH₂S—, —CF₂O—, —OCF₂—, —CF₂S—, —SCF₂—, —(CH₂)_n—, —CF₂CH₂—, —CH₂CF₂—, —(CF₂)_n—, —CH═CH—, —CF═CF—, —C≡C—, —CH═CH—COO—, —OCO—CH═CH—, CR⁰R⁰⁰or a single bond,
L, R^aand R^beach, independently of one another, denote H, halogen, SF₅, NO₂, a carbon group or hydrocarbon group, where the compounds contain at least one radical L, R^aand R^bwhich denotes or contains a P-Sp-group,
R⁰and R⁰⁰each, 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.

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

Above and below, the following meanings apply:

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.

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 CH₂groups may be replaced by —O—, —CO—, —COO— or —OCO— in such a way that two O atoms are not connected directly to one another.

The term “organic group” denotes a carbon or hydrocarbon group.

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, —C≡C—) or optionally contains one or more further atoms, such as, for example, N, O, S, P, Si, Se, As, Te or Ge (for example carbonyl, etc.). 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.

“Halogen” denotes F, Cl, Br or I.

The terms “alkyl”, “aryl”, “heteroaryl”, etc., also encompass polyvalent groups, for example alkylene, arylene, heteroarylene, etc.

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.

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 C₂-C₇-1E-alkenyl, C₄-C₇-3E-alkenyl, C₅-C₇-4-alkenyl, C₆-C₇-5-alkenyl and C₇-6-alkenyl, in particular C₂-C₇-1E-alkenyl, C₄-C₇-3E-alkenyl and C₅-C₇-4-alkenyl. Examples of preferred alkenyl groups are vinyl, E-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.

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.

The term “oxaalkyl” or “alkoxy” in this application encompasses straight-chain radicals of the formula C_nH_2n+1—O—(CH₂)_m, in which n and m each, independently of one another, denote 1 to 6. Preferably, n=1 and m=1 to 6.

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.

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 C≡C double bond or a —C≡C— triple bond, and groups which are suitable for polymerisation with ring opening, such as, for example, oxetane or epoxide groups.

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.

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.

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.

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.

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.

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.

The following examples are intended to explain the invention without limiting it. Above and below, percentages are percent by weight and all temperatures are indicated in degrees Celsius.

Throughout the patent application, 1,4-cyclohexylene rings and 1,4-phenylene rings are depicted as follows:

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The cyclohexylene rings are trans-1,4-cyclohexylene rings.

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_nH_2n+1and C_mH_2m+1are 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_mH_2m+1” means OC_mH_2m+1or C_mH_2m+1. The coding in Table B is selfevident.

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 R¹*, R²*, L¹* and L²*:

Code

for

R¹*,

R²*,

L¹*,

L²*,

L³*
R¹*
R²*
L¹*
L²*

nm
C_nH_2n+1
C_mH_2m+1
H
H

nOm
C_nH_2n+1
OC_mH_2m+1
H
H

nO · m
OC_nH_2n+1
C_mH_2m+1
H
H

n
C_nH_2n+1
CN
H
H

nN · F
C_nH_2n+1
CN
F
H

nN · F ·
C_nH_2n+1
CN
F
F

F

nF
C_nH_2n+1
F
H
H

nCl
C_nH_2n+1
Cl
H
H

nOF
OC_nH_2n+1
F
H
H

nF · F
C_nH_2n+1
F
F
H

nF · F ·
C_nH_2n+1
F
F
F

F

nOCF₃
C_nH_2n+1
OCF₃
H
H

nOCF₃·
C_nH_2n+1
OCF₃
F
H

F

n-Vm
C_nH_2n+1
—CH═CH—C_mH_2m+1
H
H

nV-Vm
C_nH_2n+1—CH═CH—
—CH═CH—C_mH_2m+1
H
H

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:

TABLE A

PYP

PYRP

BCH

CBC

CCH

CCP

CPTP

CEPTP

ECCP

CECP

EPCH

PCH

PTP

CCPC

BECH

EBCH

CPC

FET-nF

CGG

CGU

CFU

TABLE B

APU-n-OXF

ACQU-n-F

CPU-n-OXF

APUQU-n-F

BCH-n•Fm

CFU-n-F

CBC-nmF

CCP-nOCF₃

CCP-nOCF₃•F

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ECCP-nm

CCZU-n-F

ECCP-nOCF₃

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ECCP-nF•F

PGP-n-m

CGU-n-F

CGUQU-n-F

CLUQU-n-F

CDUQU-n-F

CDU-n-F

DCU-n-F

CGG-n-F

CPZG-n-OT

CC-nV-Vm

CCP-Vn-m

CCG-V-F

CCP-nV-m

CC-n-V

CCQU-n-F

CC-n-Vm

CPPC-nV-Vm

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CCQG-n-F

CQU-n-F

CP-1V-m

CP-2V-m

CP-V2-m

CP-1V-N

CP-V2-N

CCP-nF

CCP-nF•F

BCH-nF•F•F

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CCP-nF•F•F

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BCH-nF•F

Dec-U-n-F

CWCU-n-F

CPGP-n-m

CWCG-n-F

GPP-n-m

CCOC-n-m

CPTU-n-F

GPTU-n-F

PQU-n-F

PUQU-n-F

PGU-n-F

CGZP-n-OT

PGU-n-OXF

CCGU-n-F

CUQU-n-F

CCCQU-n-F

CPGU-n-OT

CPGU-n-F

CVCP-1V-OT

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GGP-n-Cl

PP-nV-Vm

PP-1-nVm

CWCQU-n-F

PPGU-n-F

PGUQU-n-F

GPQU-n-F

MPP-n-F

PGP-n-kVm

PP-n-kVm

PCH-nCl

GP-n-Cl

PCH-nF

PCH-n

PCH-nN•F•F

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GGP-n-F

PGIGI-n-F

AlK-n-F

BCH-nm

BCH-nF/CPP-n-F

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BCN-nm

CY-n-Om/PCH-nOmFF

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CP(F,Cl)n-Om

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CP(Cl,F)-n-Om

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CCY-n-Om

CCY-n-m

CAIY-n-Om

CAIY-n-m

CCP(Cl,F)-n-Om

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CCP(F,Cl)n-Om

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CCY-V-m

CCY-Vn-m

CCY-V-Om

CCY-Vn-Om

CCY-n-OmV

CBC-nm

CCP-V-m

CCP-Vn-m

CCP-n-m/CCP-nm

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CPYC-n-m

CYYC-n-m

CCYY-n-(O)m

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CCY-n-O2V

CY-n-m

CCH-nm/CC-n-m

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CCH-nOm/CC-n-Om

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CEY-n-Om

CC-n-V1

CY-n-OV

CC-2V-V2

CVC-n-m

CC-n-mV

CC-n-mV1

CP-nOmFF

CH-nm

CEY-V-n

CVY-V-n

CY-V-On

CY-n-OC(CH₃)═CH₂

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CY-n-O1V

CCN-nm

CY-1V-O1V

CCPC-nm

CCY-n-zOm

CPY-n-m

CPY-n-Om

CPY-V-Om

CPP(Cl,F)-n-(O)m

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CPY-1V-Om

CQY-n-(O)m

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CPP(F,Cl)n-(O)m

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CQIY-n-(O)m

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CCQY-n-(O)m

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CCQIY-n-(O)m

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CPQY-n-(O)m

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CPQIY-n-(O)m

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CPYG-n-(O)m

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CCY-V-Om

D-nOmFF

MEnN•F

CY-nV-Om

PCH-nm/CP-n-m

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CY-zVn-Om

PY-zVn-Om

PY-V-Om

PY-1V-Om

PCH-nOm/CP-n-Om

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DPGU-n-F

DPGU-n-OT

PP-n-m

PYP-n-mV

CYLI-n-m

CENap-n-Om

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LY-n-(O)m

CCNap-n-Om

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CNap-n-Om

YPY-n-mV

CETNap-n-Om

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CTNap-n-Om

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CK-n-F

YPY-n-m

LYLI-n-m

C-DFDBF-n-(O)m

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B-nO-Om

CPYG-n-(O)m

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DFDBC-n(O)-(O)m

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CCY-V2-(O)m

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CCY-1V2-(O)m

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CCY-3V-(O)m

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PYP-nF

MUQU-n-F

NUQU-n-F

COChrom-n-Om

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COChrom-n-m

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CCOChrom-n-Om

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CCOChrom-n-m

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CONaph-n-Om

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CCONaph-n-Om

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CLY-n-Om

CLY-n-m

LYLI-n-m

CYLI-n-m

LY-n-(O)m

COYOICC-n-m

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COYOIC-n-V

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CCOY-V-O2V

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CCOY-V-O3V

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COY-n-Om

CCOY-n-Om

PGIY-n-Om

PYP-n-m

PYP-n-Om

YPY-n-m

YPY-n-mV

Y-nO-Om

Y-n-Om

PY-n-m

PY-n-Om

PY-V2-Om

C-DFDBF-n-(O)m

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DFDBC-n(O)-(O)m

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CPU-n-VT

CPU-n-AT

DGUQU-n-F

C-n-V

C-n-XF

C-n-m

CC-n-2V1

CCVC-n-V

DPGU-n-OT

PTP-nOm

PTP-nm

CPTP-nOm

PTP-nOmFF

CPTP-nOmFF

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CPTP-n-m

PPTUI-n-m

(n = 1-15; (O)C_nH_2n+1means C_nH_2n+1or OC_nH_2n+1)

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.

TABLE C

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.

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C 15

CB 15

CM 21

R/S-811

CM 44

CM 45

CM 47

R/S-2011

R/S-3011

R/S-4011

R/S-5011

R/S-1011

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

TABLE D

Stabilizers, which can be added, for example, to the liquid-crystalline mixtures

in amounts of 0-10% by weight, are shown below.

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n = 1, 2, 3, 4, 5, 6 or 7

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(n = 1-12)

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:

TABLE E

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).

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RM-1

RM-2

RM-3

RM-4

RM-5

RM-6

RM-7

RM-8

RM-9

RM-10

RM-11

RM-12

RM-13

RM-14

RM-15

RM-16

RM-17

RM-18

RM-19

RM-20

RM-21

RM-22

RM-23

RM-24

RM-25

RM-26

RM-27

RM-28

RM-29

RM-30

RM-31

RM-32

RM-33

RM-34

RM-35

RM-36

RM-37

RM-38

RM-39

RM-40

RM-41

RM-42

RM-43

RM-44

RM-45

RM-46

RM-47

RM-48

RM-49

RM-50

RM-51

RM-52

RM-53

RM-54

RM-55

RM-56

RM-57

RM-58

RM-59

RM-60

RM-61

RM-62

RM-63

RM-64

RM-65

RM-66

RM-67

RM-68

RM-69

RM-70

RM-71

RM-72

RM-73

RM-74

RM-75

RM-76

RM-77

RM-78

RM-79

RM-80

RM-81

RM-82

RM-83

RM-84

RM-85

RM-86

RM-87

RM-88

RM-89

RM-90

RM-91

RM-92

RM-93

RM-94

RM-95

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).

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

EXAMPLES

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

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_odenotes threshold voltage, capacitive [V] at 20° C.
Δn denotes the optical anisotropy measured at 20° C. and 589 nm
Δ∈ denotes the dielectric anisotropy at 20° C. and 1 kHz
cl.p. denotes clearing point [° C.]
K₁denotes elastic constant, “splay” deformation at 20° C., [pN]
K₃denotes elastic constant, “bend” deformation at 20° C., [pN]
γ₁denotes rotational viscosity measured at 20° C. [mPa·s], determined by the rotation method in a magnetic field
LTS denotes low-temperature stability (nematic phase), determined in test cells.

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

Above and below, percentages are percent by weight. All temperatures are indicated in degrees Celsius.

Working Examples
Example 1

A liquid-crystalline mixture, preferably for PS-VA applications, of the composition

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%