Title of Invention

PROCESS FOR PRINTING SUBSTRATES ACCORDING TO THE INK-JET PRINTING METHOD

Abstract

The present invention relates to An aqueous ink composition for the ink-jet printing method, which comprises a) metallic or non-metallic, inorganic platelet-shaped particles having an average particle diameter of at least 2 µm, wherein the platelet-shaped particles are pigments that comprise (al) a core consisting of a substantially transparent or metallically reflecting material and (a2) at least one coating substantially consisting of one or more silicon oxides (SiOX layer) wherein the average molar ratio of oxygen to silicon is from 0.03 to < 0.95, or wherein the platelet-shaped particles are aluminium flakes coated with SiO, wherein 0.95 < z< 2.0, especially 1.1 <_ z s 2.0, more especially 1.4 < z< 2.0, b) a dispersant (dispersing agent) and c) a binder.

Full Text

Process for printing substrates according to the ink-iet printing method The present invention relates to a process for printing substrates, for example paper, plastics films or textile fibre materials; according to the ink-jet printing method, and to the ink compositions used in accordance with that process. US-B-6,433,117 relaxes to aqueous ink jet inks containing a copolymer dispersant comprising at least one polymerized monomer having the general formula CH2=C(R3)C(0)OXa(C2H40)b-(C3H60)c-R4, where a=0 or 1; wnen a=1 r X is an akyL aryl, or alkaryl diradicai connecting group of 1-9 carbon atoms; b and c are independently selected from the range of 0-100 provided that b and c are not simultaneously 0; P3 is H or CH3; and R4 is preferably P03H2. DE-A-1S727757 relates :o radiation curable ink jet inks containing at least one fine-grained organic or inorganic pigment. Interference pigments are mentioned as examples of inorganic pigments. Preferably 9c %; especially preferred 99 % of the pigments have a particle size Althougn organic pigments are superior to dyes in terms of fastness to light, problems arise with resoec. tc dispe^c: in water-based ink compositions and with respect to the removal of ncn-disoersbie acoiorr;erates therefrom. i: has now; surprising1}', oeen found that metallic or non-metallic, inorganic plateiet-shaped particles having an eve-age panicle diameter of from > 2 to 20 urn, especially from 3 to 15 μM can readii; oe dispersec in water-based ink compositions and the particles, if they have settiec: can readiiy s= redispersec, for example by shaking. The'present invention accordingly relates to an aqueous ink composition that comprises k) metallic or non-meia^c, inorganic platelet-shaped panicles having an average particle diameter of a: least 2 urn. 5) a dispersan: and 2} a binde\ and also tc- a process fo- pnntin: substrates according to the ink-jet printing method that comprises printing the substrates with the above-mentioned aqueous ink composition. Metallic or non-metallic, inorganic platelet-shaped particles or pigments are effect pigments, (especially metal effect pigments or interference pigments), that is to say, pigments that, besides imparting colour to an application medium, impart additional properties, for example angle dependency of the colour (flop), lustre (not surface gloss) or texture. On metal effect pigments, substantially oriented reflection occurs at directionally oriented pigment particles. In the case of interference pigments, the colour-imparting effect is due to the phenomenon of interference of light in thin, highly refractive layers. ~ne average particle diameter is determined by electron microscopy. The average particle diameter or the size graae of the platelet-shaped particles can be adjusted in accordance with the invention also by means of (test) sieving machines, for example the vibratory sieving machine "Analysette 2'. mode! PRO (Fritsch), using micro-precision sieves of 100 0 according to ISO 3310-3 with aperture sizes of 5 μm, 10 μm, 15 \μm and 20 μm. For that purpose, two sieves are positioned one above the other in the test sieving machine in such a manner that the mesh size decreases in the downward direction. This means that the material passing through the upper sieve falls onto the next sieve in the arrangement. As a result, a certain numbe- of particles are retained on the individual sieves. The size grade of those particles is characterised by the mesh size of the upper sieve (10 μm, 15μm or 20 μm, preferably 15 urn or 20 urn) and of the receiving sieve (5 μm, 10 μm or 15μrn, preferably 5 urn or 10 μm). A preferred ernbodine" of the present invention employs aqueous ink compositions in wnich meta! fiakes: especially silver flakes and aluminium flakes, are used as the platelet-shaped particles. Sue metal flakes, especially silver flakes, can be used to produce conductive inks. The term "SiOr with C.?5 ≤ : ≤ 2.0,: means that the molar ratio of oxygen to silicon at the average value c* the s'^con cxioe layer is from 0.95 to 2.0. The composition of the silicon oxide layer can be determined by ESCA (electron spectroscopy for chemical analysis). Tne term "SiCx with C.C2 ≤ x ≤ 0.95" means that the molar ratio of oxygen to silicon at the average value of the silicon oxide layer is from 0.03 to 0.95. The composition of the silicon oxide layer can be determined by ESCA (electron spectroscopy for chemical analysis). According to the present invention the term "aluminum" comprises aluminum and alloys of aluminum. Alloys of aluminum are, for example, described in G. Wassermann in Ullmanns Enzyklopadie der Industrielien Chemie, 4. Auflage, Verlag Chemie, Weinheim, Band 7, S. 281 to 292. Especially suitable are the corrosion stable aluminum alloys described on page 10 to 12 of W000/12634, which comprise besides of aluminum silicon, magnesium, manganese, copper, zinc, nickel vanadium, lead, antimony, tin, cadmium, bismuth, titanium, chromium and/or iron in amounts of less than 20 % by weight, preferably less than 10 % by weioht. The aluminium flakes are preferably obtained by means of a process (see, for example, WO00/1897B, WOC2/023512, WO33/90613, US-B-6,270,840, US-A-4,321,087; comprising the following steps: a) vapour-deposition of a separating agent onto a (movable) carrier to produce a separating-agent layer, b) vapour-deposition of an aluminium layer onto the separating-agent layer, c) dissolution of the separating-agent layer in a solvent, and d) separation of the aluminium flakes from the solvent. Tne process mentioned above makes available aluminium flakes that have a high degree of piane parallelism and a defined thickness in the region of ± 10 %, preferably ± 5 %, of the averaae thickness. The aluminium flakes nave an average diameter of at least 2 μ n, especially from > 2 to 20 μ m. more especially from 3 to 15 μ rn, and most preferred from 5 to 15 jxm. The thickness of the aluminium flakes is general!}- from 10 to 150 nm, especially from 10 to 100 nm, and more especially from 30 TO 52 μ m. lr; order to be able to use tne aluminium pigments in aqueous ink-jet compositions, it is necessary to" tnose pigments tc be protected against corrosion by water. According to R. 5esoio; AJjmhi'jmoigmenie fCr wassrige Beschichtungen - Widerspruch oder Wirkiichkeit?. "arbe - Lack ?7 (1991) 311 -314, a large number of procedures, which can be divided into two groups, are known for the stabilisation of aluminium pigments: - adsorption of corrosion inhibitors on the pigment surface * phosphoric acid esiers; DE-A-3C20073, EP-A-170474, EP-A-133644, US-A-4..5S5.716, US-A-4,833,231, - phosohates and ohosohites: US-A-4,565,716, US-A-4,808,231, EP-A-24C3S7, - vanadates : EP-A-305560, EP-A-104075, - chromates: US-A-2,904,523, US-A-4,693,754, EP-A-259592, - dimeric acids: DE-A-3002175, and - encapsulation of the pigments with a continuous inorganic protective layer: - SiO2: US-A-2,885,366, US-A-3,954,496, -Ti02:DE-A-3813335: or organic protective iayen - DE-A-3630356, DE-A-S147177, EP-A-477433, especially resins modified with phosphoric acid: EF-A-".70474, CA-A-1,273,733, AT-A-372696, DE-A-3807588, In order to produce the auminium pigment from the (multi-layered) film, first of all the separating-ageni layer is dissolved using a solvent, the film is peeled off the substrate, and the fragments of film produced as a result are comminuted, if appropriate after washing and filtering. Comminution of the fragments of film to pigment size is effected by means of ultrasound or by mechanical means using high-speed stirrers in a liquid medium, or after drying the fragments in an air-jet mill having a rotary classifier. Depending on whether the pigment comminution is earned out in a liquid medium or in the dry state, the free metal surfaces of the aluminium pigment, which is obtained in a particle size of from 5 to 60 \irr\, preferably from ',2TO 35 μ n, are covered with a passivating protective layer either during the comminution p'ocecu-e or following that procedure, by means of one of the above-mentionec processes see E::-A-82S745). A further- prefe^ec emoodiment of tne present invention employs aqueous ink compositions in which the 2ia:eiet-snaoec particles used are SiOz-( especially SiCfe-coated aluminium flakes. Tne SiO-v esosc.aiiy SlOrOoatec aluminium flakes are generally particles having an average diameter o: at ieas: 2 :rr.. especially from > 2 to 20 fim, more especially from S to 15 μ n, and most preferec £ to 'μ m. The thickness of the pigments is generally from 30 μ m to 0.5 μ mr especially rorr. 30 to 500 nm, and more especially from 40 to 300 nm, the particles having an aiuminiurn core with two substantially parallel faces, the distance between which faces is the shortest axis of the core: and having an Si02 layer applied to those paralie; faces or to tne entire surface, and, optionally, further layers. The further layers can be apolied z the pa-a:;e: faces or to the entire surface. The thickness of tne aluminium layer is generally from 10 nm to 150 nm, especially from 10 nm to 100 nm, and more especially from 30 to SO nm. The thickness of the SiOz layer is generally from 10 nm to 175 nm, especially from 15 nm to 100 nm, and more especially from 15 to 80 nm. in a particularly preferred embodiment the present invention relates to platelet-shaped aluminum particles comprising: an aluminum layer having a top surface, a bottom surface, and at least one side surface, and having a thickness o4 30 nm to 60 nm, especially 30 to 50 nm; and a SiOr layer with 0.S5 2 to 20 μ m, more especially from 3 to 15 \im, and most preferred from 5 ic 15μ m. The aluminum flakes o" the present invention are not of a uniform shape. Nevertheless, for purposes of brevity, the fiakes will be referred to as having a "diameter." The aluminum flakes have a high piane-paraiielism and a defined thickness in the range of ± 30 %, especially ± i0 % o: the average thickness. The aluminum flakes have a thickness of from 60 tc 220 nm, especia'K' from 50 to 100 nm. It is presently preferred that the diameter of the fiakes be ir a preferrec ~ange of > 2 to 20 μ m with a more preferred range of about 3-15 urn. Thus, the aspect rati: of the fiakes of the present invention is in a preferred range of about 9 to 335 with a mo-e preferred range of about 30 to 300. When the SiC2 layer is apoiied to the aluminium flakes by a wet-chemical method, as described, for example, r DE-A-19501307 5 US-B-5,763,086, DE-A-4405492 (Example 1, te::aethcxysitane)r DE-A-^457752 (CVD method, gaseous phase decomposition of organosiiicor; compounds; DE-C-4414079 (CVD method, decomposition of silicon compounds that contar nirogen but no alkanoyioxy radicals, especially decomposition of S-aminopropy!triethcxysi.ane:;. rJS-A-2,885,366 (water glass solution), the entire surface of tne auminium. flakes is covered with an Si02 layer. Preferably, tne 3iGr-coa:ec [Z .95 for example, US-5-££7:.E40, WOOQ/18978, WO02/090613; WO03/90613) which comprises the following steps: a) vapour-depositior. c' a seoarating agent onto a (movable) carrier to produce a separating-agen: layev t) vapou>oepositior o; a". SiC: layer (0.95. c) vapour-deposition of an aluminium layer onto the SiOy layer obtained in step b), d) vapour-deposition of an SiOy layer (0.95 e) dissolution of the separating-agent layer in a solvent, and f) separation of the SiOy-coated aluminium flakes from the solvent. The process mentionec absve makes available SiOy-coated aluminium flakes have a high degree of plane parallelism and a defined thickness in the region of ± 10 %, preferably ± 5 %, of the averaoe thickness. Comminution of the fragments of film to pigment size can be effected, for example, by means of ultrasound or by mechanical means using high-speed stirrers in a liquid medium, or after drying the fragments in an air-jet mill having a rotary classifer. Depending on whether the pigment comminution is carried out in a liquid medium or in the dry state, passivation of the free metal surfaces of the aluminium pigment is carried out either during the comminution procedure, or following that procedure, by means of one of the above-mentioned processes. Further interference pigments preferred in accordance with the invention, which can be prepares in analogy tc :ne above-described process, have the following layer structure: thin, semi-opaque metal layer (chromium, nickel)/dielectric layer (Si02j MgF2, Al203)/reflecting metal layer ■ aluminium, dielectric iayer/thin, semi-opaque metal layer, especially chromium/Si02-/E!umin;jm/SiC2-/chromium and chromium/MgF2/aIuminium/MgF2/chromium (US-A-E, 055.245); TMTM7M7 o* 7Iv!7M'7 wnerein WT is a semi-transparent meta! layer, especially an aluminium or aiuminiurn-based meta! ;Eyer, 7 is a transparent dielectric of low refractive index and M is a highly reflective opaque aiumr.lurn or aluminium-based layer, especially Si02/Ai/Si02/Ai/SiG2 and Si02/Ai/3iG2/Ai/SiG2.'A.SiD^(US-A-3,438,796). 7he present inventor, -e^tes assc to aqueous ink compositions in which the pigments used are those oescribec in E~-5-8CS,549 and PC7/EP03/09296. * 7hat is, there are usee r the ink composition pigments that comprise (ai) a core consisting c*" a substantially transparent or metallically reflecting material and (a2) at least one costir: substantially consisting of one or more silicon oxides wherein the average molar ratio of oxygen to silicon is from 0.03 to Preference is given tc tr.e use of pigments having the following layer structure: (a3) Si02, especially SiG2: (a2) SiOx wherein 0.0c (ai) a core consisting o: a substantially transparent or metallically reflecting material and (a2) SiOx wherein 0.03 (a3) Si02j especially SiC2: (a4) a coating consisting of any desired solid material the composition of which is different from that of the coatina 'aS}; (a3) Si02; especially Si02? (a2) SiOx wherein 0.0S (ai) a core consisting o" a substantially transparent or metallically reflecting material and (a2) SiOx wherein 0.02 (a3) SiOz, especially Si02: (a4) a coating consisting o* any desired solid material the composition of which is different from that of tne coating a3). When the core consists o: a metallically reflecting material, that material is preferably -selected fro;r A-g, A;. AL. CU: Or, Ge, Mo: Ni, Si, Ti, Zn, alloys thereof, graphite, Fe203 and McS2. Specia' preference is given to AL When the core consists r £ transparent material, the material is preferably selected from mica, Si02 wherein 1.1: Special preference is ave~ tc silicon dioxide. The materia! of coating a4] is preferably a dielectric material having a "high" refractive index, that is tc say a refractive index greater than about 1.65, preferably greater than about 2.0, most preferred greater than about 2.2, which is applied to the entire surface of the silicon/silicon oxide subsrate. Examples of such a dielectric material are zinc sulfide (ZnS), zinc oxide (ZnO): zirconium oxide (Zr02), titanium dioxide (Ti02), carbon, indium oxide (in203}: indium tin oxide (TO), tantalum pentoxide (Ta205), chromium oxide (Cr203), cerium oxide (CeOi';. yttriur oxide 'Y203), europium oxide (Eu203), iron oxides such as iron(ll)/iron(lll) oxide (Fe304) and iron(III) oxide (Fe203), hafnium nitride (HfN), hafnium carbide (HfC), hafnium oxide (Hf02), lanthanum oxide (La203), magnesium oxide (MgO), neodymium oxide (Nd203), praseodymium oxide (Pr6On), samarium oxide (Sm203), antimony tricxide {St2Z2/i silicon monoxides (SiO), selenium trioxide (Se203), tin oxide (SnG2), tuncs:en trioxoe !Vv G3/ or combinations thereof. The dielectric material is preferably a metal oxide, it being oossible for the metal oxide to be a single oxide or a mixture of oxides, with or withou: absorbing oroperties, for example Ti02) Zr02s SiO, Si02i Sn02, Ge02) ZnO, Ai205; V205, Fe2G;: Fe204s Cr203, PbTi03 or CuO, or a mixture thereof, with Ti02 and Zr02 being especially p-eferred. It is possible 10 obiair pigments that are more intense in colour and more transparent by appjying: on :op of the coating (a4), especially the Ti02 layer, a metal oxide of low refractive index, such as SiC2. A!2CS! AIOOH, B203 or a mixture thereof, preferably Si02 (WO93/082S7). Additional coatings may be applied in a manner known perse for the purpose of stabilisation with respect to weatne* and light. The metal oxide layers are preferably applied by a wet-chemical method, in which context it is possible tc employ trie wet-chemical coating techniques developed for the preparation of peari lustre olgments; Techniques of this kind are described, for example, in DE-A-146746E, DE-A-1959988, DE-A-2009566, DE-A-2214545, DE-A-2215191, DE-A-22442SE: DE-^-23:33S1; DE-A-2522572, DE-A-3137808, DE-A-3137809, DE-A-315'3^ DE-A-c-5-354r DE-A-3151355, DE-A-3211602 and DE-A-3235017, DE-A- 1959988, WO93/0E2S" anc V\'0 93/53001, or else in further patent documents and other publications. For coating, tie suDsra;-/ p^nicies are suspended in water, and one or more hydroiysable me;a! salts are adtiec a; a o- which is appropriate for hydrolysis and is chosen such that the ms:ai oxides aid/or me;a oxide hydrates are precipitated directly onto the particles without any-.instances o: seconcarv orecipitation. The pH is kept constant usually by simultaneous meie-ec adci:ior. o*' a case c akaL The pigments are subsequently separated off, washed and oriec anc. r desire: caiohec, the calcination temperature possibly being optimized in respect of the oarticuia* coating. If desired, following the application of individual coatings the pigments car. oe separate o~; dried and, if desired, calcined before being resuspended for the apoiicaticr. o" furtne- ;aye-s by precipitation (cf. US-A-5,132,873). In a"* especia!iy prefer-: embodiment, the pigment has the following layer structure: SiCx/SiCySiCx. Si02/SiCx/SiCr/SiCx/3i02, especially SiCVSiCVSiCySiCySiOz, Si(VAI/SiOXl SiC2/SiOx/AI/SiOx/SiOz, especially Si02/SiOx/AI/SiOx/Si02, Ti02/SiOa/SiOx/SiOi/SiOr/SiO/n02l especially TiO^SiO^SiOj/SiOz/SiOySiOa/TiOz or Ti02/SiOz/SiO,/AI/SiOx/SiCyTiO£, especially Ti02/Si02/SiOx/Al/SiOx/Si02/Ti02: wherein 0.03 The.SiOz layers are prefe-ab*;- obtained by heating a preferably stoichiometric mixture of fine silicon anc quartz (Si02; powaer in a vaporiser described, for example, in DE-C-4342574 and in US 6 202 591 tc more than 1300°C under a high vacuum. The reaction product is silicon monoxide gas: wuioh unoer vacuum is directed directly onto the passing carrier, where it is condensed as SiC\ wherein 1 If. under industrial VBOJJT^ O: a lev;' 10"2 Pa, Si is vaporised instead of SiO, silicon oxides that have a iess-than-ecuimoiar oxygen content are obtained, that is to say SiO> wherein C.C3 The piaments used in accordance with the invention and oescribed in EP-B-8C3549 and PCT/EP03/09295 are genera!?}-* particies having an average diameter of at least 2 jim. especially from > 2 tc 2C urn, mo-e especially from 3 to 15 Lim. The thickness of the pigments is generally from 20 nm to 1.5 jxm, preferably from 200 to 500 nm, the particles having a core, preferably of Si02 or aluminium, with two substantially parallel faces, the distance between which faces is the shortest axis of the core, and having an SiOx layer applied to those parallel faces and, optionally, further layers. The further layers may be applied to the parallel faces or tc the entire surface. The pigments are prepared according to the methods described in EP-B-803549 and PCT/EP03/09296. The comminution and classification of the pigments is carried out by means of conventional methods, for example ultrasound, grinding using high-speed stirrers, £ir separation, sievinc etc.. Tne thickness of the SiO, layer is generally from 5 to 200 nm, preferably from 5 to 100 nm. The thickness of the Si02 layer is generally from 1 to 500 nm, preferably from 100 to 350 nm. The thickness of the layer (a4), especially a Ti02 layer, is generally from 1 to 200 nm, preferably from 10 tc 150 nm. 3y using the pigments described in EP-B-803549 and PCT/EP33/09296 in ink compositions, it is possible to obtain ink compositions having a metallic appearance or having a colour that cnanaes accordinc tc the viewincanale ("flop effect"). Preferably, tne SiO>: layers, SiD2 layers and layers (a4) arranged in mirror image to the core, A' or Si02, in each cas£ have tne same layer thickness. Jn a further arrangement of the invention, the supporting layer may be surrounded on both sides by metal oxides that have a difteren; iayer thickness. Tne present invention relates aiso to aqueous ink compositions in which the pigments used are tncse oesorbed in PCT7EPC3/C2196. That is to say, there are used in the compositions pigments tha- cornnnse (£.. a core substantially consisting of one or more silicon oxides (SiOx), wherein tne average molar ratio of oxvoen tc silicon is from 0.03 to [t) optionally: an SiCr iaye- wherein 0.95 1.4 (0} optionally, a layer Z>'¥> having a transparency of from 50 to 100% and a complex refractive index N = n * //; satis^vinc the condition %{n2 -f k2 > 1.5 at the waveienath of maximum: visible reflection of the particles, which is substantially composed of carbon, an organic compound, a metal, a dielectric or a mixture thereof, and which is either on top of the core or, if an Si02 layer is present, is separated from the core by the Si02 layer. In that embodiment, tie invention is concerned with a pigment of which the particles have an average diameter of a; ieas; 2 urn, especially from > 2 to 20 p.m, and more especially from 3 to 15 jxm. The thickness of the pigments is generally from 20 nm to 1.5 ^m, preferably from 200 to 500 nm. the pa-ticies naming a core SiO* with two substantially parallel faces, the distance between which faces is the shortest axis of the core, and optionally having layers SiOz and/or DIv' applied to those parallel faces or to the entire surface, wherein - the co-e SiC; has £ tnickness o' from 20 to 350 nm and 0.03 - the SO- iaye-, which Is applied to the core, has a thickness of from 2 nm to 500 nm; and - tne layer Dw . which has a ransparencey of from 50 to 100% and a complex refractive index N = n T ik satisfying tne condition -JrP + k2 > 1.5 at the wavelength of maximum visible reflection of the partices, has a thickness of from 5 nm to 300 nm. Tne complex refractive inoex N (CRC Handbook of Chemistry and Physics, 82nd Edition, pages 12-"i33) can be" ostermhed, for example, by ellipsometry (R. M. A. Azzam & S\\ M. Bashera. Ellipsoneiry anc Polarized Light, North Holland, New Amsterdam 1997). Tne layers SO- and/cr rK' are preferably arranged symmetrically about the core SD, both with respect tc their chemica: composition and stoichiometry and to their thicknesses, having a plane of symmetry oa-a!is: tc tne plane of the greatest diameter. In addition tc the optional la/e-s SiO: and'a: Dh. any oesred further layers may also be present. Preferably, the comoosiiiont eccordin^ tc tne invention comprise particles having at least one layer Si02 or D\ especially ^aiicies navinc a: least one Si02 layer and especially also those having one SOr layer anc one lays- T\ ^reference is accordingly given more especially tc particles having the foiiow!nc jays: sequences: Sie2'SiCySiC2. especial^ Si-CVSiC/SiOg and D^SiCVSiCySiCyD" especially DM/SiC?/ SC/S02€rThe silicon in tne co-e is general:*1 oonded to from 3 to 95 atom % oxygen, especially to from 5 tc 50 atom % oxygen, more especially from 10 tc 30 atom % oxygen, per 100 atom % silicon. Trie thickness c: tne SO- layer is at least equal to the thickness of the natural oxide layer of approximately I nm ens is preferably from 10 to 350 nm thick. The thickness of the layer Z)u is especially iron- 2Z to 2JJ nm, and more especially from 30 to 100 nm. Usefui materials for the layer DM include, for example, metals such as Ag, Al, Au, Cu, Co, Cr, Fe, Ge, Mo, Nb. Ni, Si, T;, V: alloys thereof, inorganic or organic pigments or colorants, graphite and compounds similar to graphite as disclosed in EP-A-982 376, metal oxides, such as MoSz, Ti02. 2'02! SiO, Sn02, Ge02, ZnO, Al203, V205l Fe203> Cr203, PbTi03 or CuO and also mixtures thereof. The layer DM may, however, also consist, for example, of any one of the many dielectric materials whose specific resistivity according to the conventional definitio" is at least 1010 &-cm: which are likewise very well known to the person skiiiec in the an. Tne transparency of the layer DM is advantageously at least 50 %, corresponding to a reflectivity of at most 50 %. With a metal, the skilled person will know how to achieve this by means o1 appropriately thin layers, for example up tc approximately £ nm of Al or Au or up to approximately 10 nm of Co or Cu. In the case of colourless or coloured dielectrics greater thicknesses are possible. Silicon oxioes having a iess-than-equimolar oxygen content (SiOx wherein 0.03 For vapour-bsposithc t~e cce there is advantageously used metallic silicon, whicr need not oe o* high purity. That is to say. impurities may be present, for example elements o" the main groups "3, 14 and * 5 a~c o: transition elements such as Fe, AL Ge, Sn and/or Sb. The layers S'C- :r Dv may. io~ e;;arnple: be produced by vapour-deposition in like manner, in which case - fo* synmet-oa. structures - vapour-deposition commences with the iayer Dr"' or SiOz onto whicr. tne cce anc then a further iayer Si02 or DW are vapour-depcsited. When layers SiCr anc Zu' are ootr desired, the procedure is: for example, as described According to that embodiment, special preference is given to pigments having the following layer structure: (b2) SiOz layer, especially Si02 layer, (b') SiCx core wherein 0.03 (o3) iayer DIV', especially TiO^: (b2) Si02 layer, especially Si02 layer, (D*) SiO>: core wherein. COS : The materials for the layer Dw' are generally selected from metals, such as Ag, Al, Au, Cu, Co, Cr, Fe, Ge, Mo, Nb, Ni, Si, Ti, V, alloys thereof, inorganic or organic pigments or colorants, graphite and compounds similar to graphite, metal oxides such as MoS2l Ti02j ZrC2l SiO, Sn02, GeO*. ZnO, Al203, V205> Fe203, Cr203, PbTi03 or CuO, and mixtures thereof. The iayer DM preferably consists of Ti02. in high-value applications, for example automotive finishes, it is possible, for example, for tne weathering resistance to be increased by means of an additional protective layer, from 2 tc 250 nm thick (preferably from 10 to 100 nm thick), of an inorganic dielectric of nD The piateiei-snapeb panicles of the present invention are known or can be prepared in analogy to known processes: DE-A-19844357, EP-A-990715, US-B-5,135,812, JS-5-5r270:84D; WO93'08££7, WO00/18978, WO01/57287, EP-A-80354S, PCT/EPC3/02- 95 anc PC7/E?a3/Q9296. ""he oiateiet-shapec particles can be used on their own or in combination with organic and inorganic pigments anc colorants. When, for example, fiakes having the structure SiCx;^5 nm)/SiC={24C nm)/SiC-x(45 nm) (x=0.3 +/-10%) (2 = 1 +/-10%) and a black colorant, for example IRGASPERS5© 5;ack R-W (Ciba Spezialitatenchemie AG), are usee to produce an ink composition, tnen if the ink is applied to an absorbent paper, a brilliant light-blue colouration with floe tc -ec1 is- obtained. The ink compositions according to the invention generally contain from 0.1 to 20 % by weight, preferably from 0.2 to 10 % by weight, of pigment (or colorant). As component (E), tne :nk compositions according to the invention comprise customary dispersants, for example water-soluble dispersants based on one or more condensation products of arylsulfonic acid and formaldehyde (B1) or on one or more water-soluble alkoxylated phenois Tne dispersants (B*; to wmcn preference is given are condensation products having a maximum*sulfonic acic group content of 40 % by weight. The condensation p~oc^otc .'El) are obtainable by sulfonation of aromatic compounds, such as naphthalene itself or naphthalene-containing mixtures, and subsequent condensation with formaldehyde of the arylsulfonic acids formed. Arylsulfonic acids that a-e especially suitable usually comprise a- and B-naphthalene- sulfonic acids in which tne ratio of the a-isomer to the p-isomer is usually from 20 :1 to 1 : 8, especially iC : 1 :c ' : 5. As the added carboxyiio acic there are suitable aromatic carboxylic acids or derivatives thereof, such as naohtnaieneoarboxylic acid, naphthalic acid, terephthalic acid, isophthaiic acid, benzoic acic.. trimeliitic aoid: phenylacetic acid, phenoxyacetic acid, salicylic acid, p-hydrcxybenzoic acic: dipheryiacetic acid, m-hydroxybenzoic acid, benzenetetra- carboxyiic acic anc acio anhydrides, such as phathalic anhydride, trimeliitic anhydride, benzene--; ,Z.- Suitable ionc-chainec ai;ona:ic carboxylic acids are especially saturated or olefinically unsaturated, ihea* or canchec aiiphatic monocarboxylic acids having from 8 to 22, preferably from 8 t: ', I, carbon atoms of natural or synthetic origin, for example Higher fatty acids, such as capviic acid, oapric acid, iauric acid, myristic acid, palmitic acid, stearic acic. oleic ac;c: ::no e;: acic or iinolenic acid or synthetically produced carocxyiic acids, such as 2-etnyinexanoic acid, isononanoic acid or isotridecanoic acid. Also oJ. interest are m:xtj-ss o: anhydrides, mixtures of carboxylic acids, mixtures of salts of the carbcxyi;c acics tna* come into consideration and aisc mixtures of carboxylic acids anc anhydrides. Specie: preference is given :c sodium Denzoate, sodium phenylacetate, sodium salicyiate! sodium. 4-hydrc>:yberiZcatr: sc-cium terephthalate, sodium 2-hydroxy-3-naphthaiene- oarboxyiate, naphthalene-* -carocxylic acid, phthalic anhydride or benzoic acid. Dispersants ;E*} espec;a;:\ o-sf&med for the ink compositions according to the invention contain from 50 to 97 % by weignt. especially from 70 to 95 % by weight, arylsulfonic acid/formaldehyde condensation products and from 3 to 50 % by weight, especially from 5 to 30 % by weight, aromatic or long-chained aliphatic carboxylic acids, their salts or their anhydrides, or mixtures thereof. The dispersants (B1) are known and are described, for example, in US-A-5,186,846 and DE-A-19727767. wherein a is from 0 to on average 125, b is on average from 57 to 250: wherein when b>37 the ratio of b : a is at least 1:1, and d is 0 or 1: or mixtures thereof. Preference is given tc dispersants (B2) wherein a is from 0 tc on average 2.5, b is on average from. 37 to 250 anc c is from 0 to on average 0.5. Special preference is given to disoersants (32; ir^whicr t is from 0 to on average 2.5, b is from on average 50 to 100 and d is on average C.5. The dispersan:s (B2' are Known and are described, for example, in US-B-4,218,218 and Suitable non-lomc dispersants (B3) are especially compounds selected from the group of the - aikyiene oxide adducts of formula K V 0—f-Elkvienc - C T. K I 00) i :'V ) i wherein Y1 is d-C12alkyl, aryi or aralkyl, "aikyiene" is an ethylene radical or propylene radical and rrn is from i to 4 and n- *s from 4 to 50, - aciciucts of akyiene cxce with saturated or unsaturated mono- to hexa-hydric aliphatic alcohols, fatty acids, fatty amines, fatty amides, diamines, or sorbitan esters, - - alkyiene oxide condensation products (block polymers) - polymerisation products of vinylpyrrolidone, vinyl acetate or vinyl alcohol and - co- or ter-polymers of vinylpyrrolidone with vinyl acetate and/or vinyl alcohol. Preferred alkyiene oxiae adducts are - an alkyiene oxide addition product of from 1 to 100 mol of alkyiene oxide, e.g. ethylene oxide and/or propylene oxide > with 1 mol of an aliphatic monoalcohol having at least 4 carbon atoms, of a tri- tc hexa-hydric aliphatic alcohol, or of a phenol unsubstituted or substituted by alky!, phenyl, a-toiyiethyl, benzyl, omethyibenzyl or by a,a-dimethylbenzyl; - an alkyiene oxide addition product of from 1 to 100 mol, preferably from 2 to 80 mol, of ethylene oxide; wherein individual ethylene oxide units may have been replaced by substituted epoxides, sue:* as styrene oxide and/or propylene oxide, with higher unsaturated or saturated monoalconc;s. fatty acids, fatty amines or fatty amides having from 8 to 22 carbon atoms: - an alkyiene cxide addii,c~ p-ocuct. preferably an ethylene oxide/propylene oxide adduct with ethyienediamine: - an ethoxyiatec sorbite:* ester Having long-chained ester groups, for example polyoxyethylene'sorbitan monoiaurate having from 4 to 20 ethylene oxide units or polyoxyethyiene'sorbitar rioieate having from 4 to 20 ethylene oxide units. Preferred alkyiene oxloe condensation products are adducts of ethylene oxide with polypropylene oxide (s:~oa!ied EO-PO biock polymers) and adducts of propylene oxide with poiyethyiene oxide ;s:-o^;50 reverse EO-PO block polymers). Specia; preference is given xz ethylene oxide-propylene oxide block polymers in which the molecular weignt of the co yoropylene oxide base is from '700 to 4000 and in which the ethylene oxide content r :ne total molecule is from 30 to 80%, especially from 50 to 80%. An especially oreferrec" embodiment of the present invention employs polymeric acids (B4), which function botr as dispersants and as binders. Examples of such compounds are listed below: (a) polyacrylic acid and copolymers ("copol") thereof, such as copol. (styrene/acrylic acid), copol. (ethyl acrylate/acryfic acid), copol. (ethylene/vinyl acetate/acrylic acid), copol. (MMA/H EGAc/acryiic acid), cope;. (styrene/MMA/acrylic acid), copol. (styrene/MMA/PEGAc/acrylic acid); (b) poiymethacrylic acid and copolymers thereof, such as copol. (styrene/methacr/lic acid), copol. (ethyl acryiate/methacrylic acid)> copol. (ethylene/vinyl acetate/methacrylic acid)3 copol. (MWlA/HA/EGAc'methacrylic acid), copol. (benzyl rnethacrylate/triethylene glycol/methacrylic acid,: copol. (styrene/MMA/methacrylic acid), copol. {styrene'MMA/PEGAc;nsthac,yiic acid); (c) styrene-maleic acid copolymers, styrene-maleic anhydride copolymers; and also (d) polyvinylbenzoic acid (PYBA) and copolymers thereofs such as copol. (MMA/HAVinylbenzoic acid), copoi. (MMA/HA/PEGAc/vinylbenzoic acid) and copol. (MMA'EA/PEGAc'vinylbenzoic acid) (see, for example, US-B-6 417 249). A iarge number of polymeric acids are available commercially. Examples include the poiymeric acids obtainable from BYK Chemie Co. under the trade names Disperbyk® 110, 111, 18Gr 181,182, 132, 184 and 190 and BYK 380 and 381. Further poiymeric acids are obtainable from Zeneca Co. unde- the trade names Neocryl© BT175, BT520, TX-K 14, A6037, XK12, K990 and BT4^. in that embodiment, the aqueous ink composition comprises a> metallic or non-me;al!ic. inorganic platelet-shaped particles, b) a poiymeric acid, especially Disperbyk® 190, which functions both as a dispersant and as a binder. Tne ink compositions according iz the invention generally contain from 0.1 to 20 % by weight ore-erably from C.5 tc 1C % by weight, of dispersant (B). Tne pigment p-eparaticns according to the invention contain as component (C; t binder that is p^eferaoly cjrabie by radiation. According to the invention, such binders are those which are curaDie by nigh-energy -adiation, that is, electromagnetic radiation especially of from 22C to 45C nm (UV radiation; or electron beams. Both free-radically polymerisable and cationicaliy polymensable binder components and also mixtures thereof are suitable. Such binde~ systems are generally known and are described, for example, in Chemistry' £. Technology of UV & EE Formuiation for Coatings, Inks & Paints, SUA Technology, London (1931), in The Printing inf. Manual, Fourth Edition, Van Nostrand Reinhold (international), London (1989), UV & EB Curing Formulation for Printing Inks and Paints, SITA Technology, London (1984) and in the company paper Vinyl Ethers, The innovative Challenge, BASF Aktiengesellschaft (1997). Acryiate group-containhg, vinyl group-containing and/or epoxy group-containing monome~s: p-epoiyme's and polymers and mixtures thereof may be mentioned as examples of suitable binder components (C). Acryi&ie group-con;^n;ng binoer components (C) are especially acryiate-based or methacryiate-oasec p'eooiymers, acrylate compounds being especially suitable. Preferred (meth)acry,ate compounds generally contain from 2 to 20, especially from 2 tc 10 and more especially from 2 to 6, copolymerisable, ethylenically unsaturated double bones. The average molecular weight (number average) of the (meth)acrylate compounds is preferably 15 000, especially below ofuran as 1 eluant). As (meth)acryiate compounds there may be mentioned, for example, (meth)acrylates and especially acrylates o: poiyhydric alcohols, especially those which, apart from containing hycroxyi groups, contain no further functional groups or possibly contain ether groups. Examples of such alcohols are dihydric alcohols, such as ethylene glycol, propylene glycol and me higher condensed representatives thereof, for example Methylene giycoL triemyiene glycol, dipropylene glycol and tripropylene .glycol, butanedio.\ pentanedic' nexanedioi, neopentyl glycol, alkoxylated phenolic compounds. such as ethcxy.a-.ee a" propcxyiated bisphenols, cyclohexanedimethanol, trihydric alcohois and Eicchois z: nigher valency, such as glycerol, trimethyiolpropane, Dutanetrio!. rimetr.yio:Stnarie: pentaerythritol, ditrimethySolpropane, dipentaerythritol, sorbitol, manni-.o ar.c :n~ corresponding alkoxylated alcohois, especially ethoxyiated and p'opoxyia:ec abcr o;s. Funne: (met'*, -acyiate crmoojnds that may be mentioned are polyester ;metr;;acry;a;£s. whicr £.-= the ,meth)acrylates of polyesterois; they may be saturated or unsaturated. Tne po:yes:erois tha; come into consideration are, for example, those which can be p-eparec ry esierification of poiycarboxylic acids, preferably dicarbcxylic acids, with pojyois: p~e"s:ab!y diois. Polyester (metmacryiatss car: be prepared in a plurality of steps or in one step, as described m EF~A-27£3CZ:. from (meth)acrylic acid, poiycarboxylic acid and polyol. Tne acryia:e compouncs. may turthermore be epoxy or urethane (meth)acrylates. Epoxy (meth)acryiates include, for example, those obtainable by reaction of epoxidised olefins or mono-, di- or poly-glycidy! ethers, such as diglycidyl ether of bisphenol A, with (meth)acrylic acid. Urethane (meth)acrylates are especially reaction products of hydroxyaiky; (meth)ac*yiates with poly- or di-isocyanates. Mention may also be made of me;amine acrylates anc silicone acrylates. The acryiate compounds may aiso have been non-ionically modified (for example ;";oVided with amino groups) or ionically modified (for example provided with acid groups L-r ammonium groups, and may be used in the form of aqueous dispersions or emulsions (for example EP-A-704469, EP-A-12339). Furthermo-e. the soivsniiess acryiate polymers can be mixed with so-called reactive diluents tc obtain the cesirec viscosity. Suitable reactive diluents include, for example, vinyl group-containing monomers, especially N-vinyi compounds, such as N-vinylpyrroiidone, N-vinylcaprolactam and [\-vir.yiformamide anc vinyl ethers, such as ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyL amyi: 2-ethylhexyl, dodecyi, octadecyl and cyclohexyl vinyl ether, ethylene glycol mono- and d.-vinyi ethen dl-: tri- and tetra-ethylene glycol mono- and di-vinyi ether, poiyeihylene Glycol ci/.ny; etner. ethylene glycol butylvinyl ether, triethylene glycol methyiviny! ether, poiyetnyiene glycol methylvinyl ether, butanediol mono- and di-viny! ethev hexanedio-mon;- and di-vinyi ether, cyclohexanedimethanol mono- and di-viny! ether trimethyioipropane triviny! ether, aminopropylvinyl ether, diethylaminoethylviny! ether and poiytetrahycofurar, divinyl ether, vinyl esters, such as vinyl acetate, vinyl o-opior.ate, vinyl stea-ate anc vinyi laurate, and aromatic vinyl compounds, such as vhyitoiuene styrene 2 Other sjitapir oinder components (C) are epoxy group-containing compounds, such as cycicpeniens cxioe. eye cnexene oxide, epoxidised polybutadiene, epoxidisec soybean oil. 3 r4-epc;:ycycione):yime:ny!}-S,4-epoxycyciohexanecarboxylate and glycidyi ethers, for example ojianedlo d^giycidyi ether, hexanediol diglycidyl ether, diglycidyl ether of bispnenol f- and per^evthrito! digiycidyi ether, the concomitant use of cationicaliy poiymerisabie monomers, for example unsaturated aldehydes and ketones, dienes, such as butadiene, aromatic viny! compounds, such as styrene, N-substituted vinyiamines, such as viny: carbazcie s.rtz cyclic ethers, such as tetrahydrofuran, likewise being *"i ^ C? -; j - : c, fJ W O W* t *- The pigment preparations according to the invention generally contain from 0.1 to 20 % by weight, preferably from 1 ic 15 % by weight, of binder component (C). y - The pigment preparations according to the invention may furthermore comprise, especially when curing of the binder is to be effected by UV radiation, a photoinitiator (D) which initiates polymerisation. Phoioinitie*ors suitable for free-radical photopolymerisation procedures, that is the polymerisation of acryiaies and, if desired, vinyl compounds, include, for example, benzophenone and ber.zophenone derivatives, such as 4-phenylbenzophenone and 4-chlorobenzophenone, acetophenone derivatives, such as 1-benzoylcyclohexan-l-oi, 2-hydroxy-2,2-dimethyiacetopherioneand 2,2-dimethoxy-2-phenylacetophenone, benzoin and benzoin ethers, such as methyl, ethyl and butyl benzoin ether, benzil ketals, such as benzii dimethyl keiai, 2-methyl-1-[4-(methylthio)phenyl]-2-morphoIinopropan-1-one, acyiphosphine oxioes, such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bisacylphosphine oxides. Photoinitiators suitable for cationic photopolymerisation procedures, that is the polymerisation of vinyl compounds or epoxy group-containing compounds, include, for example, aryidiazonium salts, such as 4-methoxybenzenediazonium hexafluorophosphate, benzenediazonium tetrafiuoroborate and toluenediazonium tetrafluoroarsenate, aryiiodonium salts, sue." as diphenyliodonium hexafluoroarsenate, arylsulfoniurn salts, sucr. as triphenyisulfonium hexafluorophosphate, benzene- and toluene-sulfonium hexafluorophosphate anc b!s[4-diphenyisulfonio-phenyl]sulfide bishexafluorophosphate, disulfones: such as dipheny: disuifone and phenyl 4-tolyi disulfone, diazodisulfones, imidotrifiates, oenzoir, tcsyiates, isoquinolinium salts, such as N-ethoxyisoquinoiinium hexafluorophosphate, pnenylpyridinium salts, such as N-ethoxy-4-phenylpyridinium hexafluorophosphate, picoliniunt salts, such as N-ethoxy-2-picoIinium hexafluoro-pnosphate, ferroceniur salts and iitanocenes. Wnen a pnotoinitiator I is present in the ink compositions according to the invention, vvn;cK is usualiy necessary whs- curing of the binder is by UV rays, then the content tnereo'- is generally from C.i to '. C % by weight, preferably from 0.1 to 8 % by weight. Water is the chief component (E; of the ink compositions according to the invention. Its conten: is generally frc~ 35 ;c 2C % by weight, preferably from 45 to 80 % by weight. The ink compositions acco'oho to the invention may comprise, as additional component (F;, an agent having a water-retaining action (humectant), which makes it especially suitable for tne ink-jet meinod. Tnere are suitable, as component (F), polyhydric alcohols, preferably unbranched and branched C3-C0alkanois. such as ethylene glycol, diethylene glycol, triethylene giycoi, tetraethylene glycol, propylene giycoi, dipropylene glycol, glycerol, erythritol, pentaerythritol, pentitols: such as arabitol, adonitol and xylitol, and hexitols, such as sorbitol, mannitol and dulcitoi, with special preference being given to the C3-C6alkanols, especially sorbitol. Poyalkyiene glycols, wnich are also to be understood as including the lower (di-, tri- and tetra-)aikyiene glycols, a^e also suitable as component (F). Preference is given to poiyaikyiene giycois Having average moiecular weights of from 100 to 1500, with special preference being given xo polyethylene glycols having an average molecular weight of Preferred ink compositions according to the invention comprise, as component (F), a combination of polyhycric alcohol and poiyaikyiene glycol generally in an amount of from 0.1 to 35 % by weight, especially from 5 to 25 % by weight, based on the weight of the preparation. There are furthermore suitable, for maintaining the fluidity of the pigment preparations according tc the invention, water-soluble solvents that do not readily vaporise, such as !\!-methyipyrroiidone, 2-pyrrolidone and ethoxylation products of glycerol and penta- erythritoi. which may be added in amounts of from 0 to 15 % by weight. Tne ink compositions o; :ne present invention may comprise, as further component (G), a wetting agen:: especia!:> £• polymer of formula wherein m; n x and y a'e each integers that indicate the number of repeating units, x is generally in tne range ?'c~" £ to 60, especially from 10 to 50, and more especially in the ra^ge from 12 tc 45. y is generally in the range from 2 to 20, especially in the range from 3 tc 18, and mos: especially in the range from 5 to 16. The ratio of x:y is generally from 10:90 to 90:10, especially from *2:8£tc 30:20 and more especially from 14:86 to 75:25. n is generally in tne range fro- S to 60, especially from 4 to 40 and more especially from 5 to 30. r~ is generally in the range from 10 tc 98, especially from 15 to 70 and more especially from 20 to 50. The ratio o* n:m is generally from 2:98 to 10:90, especially from 3:97 tc 15:85 and more especially from 5:95 :o 20:80. The values of x: y, n and m are such that the polymer nas a weight-average average moiecular weight of from 1200 to 60 000, especially from 3000 to 55 000 and more especially from 6000 to 50 000. Polymers of the above formula are available commercially, for example TEGOPREN® 5883 and 5884 (Goldschmidt Chemical Corp., Hopewell, Va.), in which the ratio of ethylene oxide to propylene oxide is approximately 77:2S (weigh:), the ratio of n:m is approximately 1:6, and the weight-average molecular weight is approximately 50 000, TEGOPREN® 5851, 5863, 5852, 5857 and SILWET® L-721G: L-722C. ^-7230, L-7002, L-7500, L-7001, L-7200, L-7280 and L-7087 (Witco Corp.; Qreenwic".; Conn,';. The poiymer may be aoced in amounts of from 0.2 to 3 % by weight, especially from 0.3 to 2 % by weigh;, more especially from 0.5 to 1.5 % by weight, based on the weight of the ink composition (US-B-6,12^.376). It will be understood thai :ne pigment preparations according to the invention may comprise further adjuvants, such as are customary especially for (aqueous) ink-jet inks and in the printing and coatings industry. There may be mentioned, for example, preservatives (such as gutardialdehyde and/or tetramethylol acetyieneurea, antioxidants, degassers/defoamers.. viscosity regulators, flow improvers, anti-settling agents, gloss improvers, lubricants, adhesion promoters, anti-skin agents, matting agents, emulsifiers, stabilisers, hydrophobic agents, light-stabilising additives, handle improvers and antistatics. The total amount of such substances as a component of the pigment preparations acceding ;: ;ne invention is generally Tne viscosity of the im: compositions according to the invention is usually from 1 to 2D mPa s. preferaoiy rem 2 ic 5 mPa s. The surface tension of the pigment preparations according to the inventicr is generally from 20 to 70 mN/m. The pH value of the ink compositions according :: :ne invention is generally from 5 to 11, preferably from £ to 8. ~ns ink compositions scccdlnc to the invention are suitable for use in recordino svstems in which the ink is expresse: in tne form of droplets from a small aperture and directed onto a sjostrate, especially a piana" substrate, on which an image is formed. Suitable recording systems include, for examo'c: commercially available ink-jet printers for use in paper printing c textile printing. The ink compositions according, to the invention can be printed on any type of substrate material. As substrate materials there may be mentioned, for example: - cellulose-containing materials, such as paper, pasteboard, cardboard, wood and wooden materials, which may also be iacquered or coated in some other way, - metallic materials, sucr, as foils, sheet metal or workpieces of aluminium, iron, copper, silver, goic, zinc or alloys of those metals, which may be lacquered or coated in some other way: - silicate materials, sucr as glass, porcelain and ceramics, which may likewise be coated, - polymeric materials of any kinc; such as polystyrene, polyamides, polyesters, polyethylene, polypropylene, melamine resins, polyacrylates, polyacrylonitrile, polyurethanes, polycarbonates, poiyvry: cnicribe and corresponding copolymers and block copolymers, - textile materials, sucr as fibres, yarns, twisted yarns, knitted goods, wovens, non-wovens and made-up goods of polyester or of modified polyester, polyester blends, cellulose-containing materials, sucn as cotton, cotton blends, jute, flax, hemp and ramie, viscose, wool, silk, poiyamide, pcyamlde blends, polyacrylonitrile, triacetate, acetate, polycarbonate, polypropylene, polyvinyl chloride, polyester microfibres and glass fibre fabrics, - ieathers, bc:r natura; ;eathe* and synthetic leather, in the form of smooth-finished leather, nappa leather or veiojr leather, - foodstuffs and cosmetics. As examples of pape" tna; car. be printed with the inks according to the invention there may be mentioned commercially available ink-jet paper, photo paper, glossy paper, piastics-coatec paper, e.c. Epsc* ink-je: Paper, Epson Photo Paper, Epson Glossy Paper, Epson Giossv Film, H~ Specie ;nk-ie: Paper, Encad Photo Gloss Paper and Ilford Photo Paper, P.astics films that car DS prin:ec with the inks according to the invention are, for example, transparent o- cioudy/opacue. Suitable plastics films are, for example, 3M Transparency Rim. Preference is g;ve^ to cbssy paper, such as, for example, Epson Glossy Paper. As textile fbre ma:eria:£ 'r:e:~ come into consideration especially nitrogen-containing or hydroxy group-containinc fibre materials, for example woven textile fabric made of cellulose, silk, wool or synthetic ppiyamides, especially silk. in tne case of tne "nk-jet printing method, individual droplets of ink are sprayed onto a sjostrate from: a nozzle in a controlled manner. It is mainly the continuous ink-jet method and tne drop-on-demand method that are used for that purpose, in the case of the continuous ink-jet metnoo, tne cropiets are produced continuously, droplets not required for the printing operation being discharged into a receptacle and recycled. In the case of the drop-on-demand method, on the other hand, droplets are generated as desired and used for pointing; that is to say, droplets are generated only when required for the printing operation. Tne production of the aroplets can be effected, for example, by means of a piezc ink-jet head or by thermal energy (ouhhie jet). For the process according to the invention, printing by means of a piezo ink-jet head is preferred, but preference is given also to printing accordinc to the continue JS hk-ist method. Subsequent curing of the binder, that is fixing the print, can be carried out in customary manner by the appibatic* of neat or high-energy radiation. For that purpose the print is irradiated either under a' inert gas atmosphere (e.g. nitrogen) with electrons (eiectron beam curing) or with high-energy electromagnetic radiation, preferably in a wavelength range of from 220 to 45C nm. The light intensities selected should be adapted to the curing rate in order 10 avoid degradation of the colorant. With a lamp output of from 120 to 240 W/cm. the curing ra:e may be, for example, up to 100 m/min, depending on the concentration and the na:ure of the photoinitiator. Tne ink compositions according to the invention are distinguished, as ink-jet inks, by advantageous aoplicaticr. properties overall, especially good flow behaviour, and yield pr.nts having a high deg'ee of fastness to light and to water, Tre hk-jet-hks o* tne present invention comprising effect pigments, are also useful for providing visble. non-cccyabie markings on documents to denote that they are original documents. "Non-copyacie1' shali mean that upon conventional copying techniques such as photocopying, scanning and reprinting, color-copying, and the like, a given property cannot be copied anc impart tne same property in substantially the same way. For example, if a ma- "T- e following Examples se~ve to illustrate the invention. Unless stated otherwise, temperatures are given in degrees Celsius, parts are parts by weight and percentages are percentages by weight. The relationship between parts by weight and parts by volume is the same as that between kiiograms and litres. Examples Example 1 A iaye^ of app-cximateiy 5C nm of NaCI is vapour-deposited onto a metallic carrier in a vacuum chamber at a pressure of less than approximately 10~2 Pa at about 900°C. Then, at the same pressure, the following materials are successively vapour-deposited: SiO (as reaction product of Si and S:0L a; from 1350 to 1550°C), Al (at 1400 to 1500°C) and SiO, whereby a film having the layer structure SiO/AI/SiO is produced on the metal belt. The separating agent is then dissolved in water, whereupon flakes come away from the substrate. At atmospheric p-essure, the resulting suspension is concentrated by filtration and rinsed several times with oe:on;sed water in order to remove Na+ and CI" ions that are present. That is followed b\ the steps of drying and heating of the plane-parallel SiO/AI/SiO structures in the form of loose material at 500°C for two hours in an oven through which air heatec to 530°C is passed. Or. neating of the platelets, the SiO layer is converted into an SiGs ;ayer. After cooiho; comminution and grading by air-sieving are carried out. Tne resulting Si02(40 nm, Al " DC nm)/SiO2(40 nm) flakes are then ground to form particles havnc an average oianete* o"'" C urn, which is measured by means of electron microscopy. Tne above-mentioned 3;C, -C nm)/AI(100 nm)/SiO2(40 nm) flakes are used to prepare an ir.k composition c*" tne •emulation indicated below: Tne ink can then be dispensed simply by shaking, since the 5i02/AI/Si02 flakes are readily disoe-siDle in water-basec systems. Application Example 1 The ink composition oDtahec in Example 1 is printed on a commercially available ink-jet paper using a drop-on-demand ink-jet printer. The prints have a metallic appearance. By proceeding as indicated in Example 1 but using, instead of the SiO2(40 nm)/AI(100 nm)/SiO2(40 nm) flakes, the flakes listed in the Table below, there are likewise obtained prints having a metallic appearance, colour flop, a high colour brilliance and/or a high tinctorial strength. New Claims 1 to 13 1. Ar-aqueous ink composition for the ink-jet printing method, which comprises a) metaiiic or non-metallic, inorganic platelet-shaped particles having an average particle diameter of at least 2μm , b) a dispersant (dispersing agent) and c) a binder 2. An aqueous ink composition according to claim 1, wherein the platelet-shaped particles are aluminium flakes. 3. An aqueous ink composition according to claim 1, wherein the platelet-shaped particles are aluminium flakes coated with Si02 wherein 0.95 4. An aqueous ink composition according to claim 1, wherein the platelet-shaped particles are pigments that comprise (al) a core consisting of a substantially transparent or metallically reflecting materia! and (a2) at least one coating substantially consisting of one or more silicon oxides (SiOx layer) wherein the average molar ratio of oxygen to silicon is from 0.03 to 5. An aqueous ink composition according to claim 4, wherein the pigment has the following layer structure. (a3) Si02, especially SiCj2; (a2) at least one coating substantially consisting of one or more silicon oxides wherein the average molar ratio of oxygen to silicon is from 0.03 to (a1) a core consisting of a substantially transparent or metallically reflecting materia!, and (a2) at least one coating substantially consisting of one or more silicon oxides wherein the average molar ratio of oxygen to silicon is from 0.03 to (a3) SiOz, especially Si02, or (a4) a coating consisting of any desired solid material the composition of which is different from that of the coating (a3), (a3) SiOZl especially Si02, (a2) at least one coating substantially consisting of one or more silicon oxides wherein the average molar ratio of oxygen to silicon is from 0.03 to (a1) a core consisting of a substantially transparent or metallically reflecting material, and . _ (a2) at least one coating substantially consisting of one or more silicon oxides wherein the average molar ratio of oxygen to silicon is from 0.03 to (a3) SiOz, especially Si02] (a4) a coating consisting of any desired solid material the composition of which is different from that of the coating (a3). 6. An aqueous ink composition according to claim 5, wherein the gloss pigment has the following layer structure: SiOx/SiOz/SiOx, SiOz/SiOx/SiOz/SiOx/SiOz, especially Si02/SiOx/SiOz/SiOx/Si02, SiOx/AI/SiOx, Si02/SiOx/AI/SiOx/SiOZl especially Si02/SiOx/AI/SiOx/Si025Ti02/Si02/SiOx/Si02/SiOx/SiOzn"i02) especially Ti02/Si02/SiOx/SiOr/SiOx/Si02/Ti02 or Ti02/SiOz/SiOx/AI/SiOx/Si02/Ti02, especially Ti02/Si02/SiOx/AI/SiOx/Si02/Ti02, wherein 0.03 7. An aqueous ink composition according to claim 1, wherein the platelet-shaped particles are gloss pigments comprising (a) a core substantially consisting of one or more silicon oxides (SiOx layer) wherein the average rnoiar ratio of oxygen to silicon is from 0.03 to (b) optionally, an SiO= layer, wherein 0.95 (c) optionally, a layer Du having a transparency of from 50 to 100% and a complex refractive index N = n + ik satisfying the condition \n2 + k2 > 1.5 at the wavelength of maximum visible reflection of the particles, which is substantially composed of carbon, an organic compound, a metal, a dielectric or a mixture thereof, and whic" is either on top of the core or, if an Si02 layer is present, is separated from the core by the SiOz layer. 8. An aqueous ink composition according to claim 7, wherein the gloss pigment has the following layer structure: (b2) SiOz layer, especially Si02 layer, (b1) SiOx core wherein 0.03 (b3) layer D, especially Ti02, (b2) SiOz layer, especially Si02 layer, (b1) SiOx core wherein 0.03 x 9. An aqueous ink composition according to claim 8, wherein the materials for the layer DMare selected from metals, such as Ag, Al, Au, Cu, Co, Cr, Fe, Ge, Mo, Nb, Ni, Si, Tit V, alloys thereof, inorganic or organic pigments or colorants, graphite and compounds similar to graphite, metal oxides or sulfides, such as MoS2, Ti02, Zr02( SiO, Sn02, Ge02, ZnO, A103) V205, Fe203, Cr203, PbTi03 or CuO, and mixtures thereof. 10. A process for printing a planar substrate according to the ink-jet printing method, which comprises printing the substrate with an aqueous ink composition according to any one of claims 1 to 9. 11. A platelet-shaped aluminum particle comprising: an aluminum layer having a top surface5 a bottom surface, and at least one side surface, and having a thickness of 30 nm to 60 nm, especially 30 to 50 nm; and a SiOz layer with 0.95 12. A process for producing Si02-coated (0.95 the following steps: a; vapour-deposition of a separating agent onto a (movable) carrier to produce a seoaratino-aaent laye b; vapour-deposition of an SiCX layer (0.95 epecially 1.10 aluminium flakes in the form of loose material or in a fluidised bed at a temperature of more than 200'C. 13. Si02-coated (0.95 ≤ z ≤2.0) aluminium flakes, obtainable by the process according to claim 12.

Documents:

920-chenp-2005-abstract.pdf

920-chenp-2005-claims.pdf

920-chenp-2005-correspondnece-others.pdf

920-chenp-2005-correspondnece-po.pdf

920-chenp-2005-description(complete).pdf

920-chenp-2005-form 1.pdf

920-chenp-2005-form 18.pdf

920-chenp-2005-form 26.pdf

920-chenp-2005-form 3.pdf

920-chenp-2005-form 5.pdf

920-chenp-2005-pct.pdf