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  1. #1
    Mustafa Umut Sarac's Avatar
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    Plasmonic Effect, Nano Particles of Gold, Silver, Copper and Best possible colorant

    Silver, gold, and copper colloids have been the major focus of interest because of their unique optical properties
    determined by the collective oscillations of electron density termed plasmons, which give rise to an intense absorption
    in the near UV–visible. Such strong absorption induces the brilliant color of these metal nanoparticles in colloidal
    dispersion
    . It is produced by the strong coupling of nanoparticles to the electromagnetic radiation of incident light,
    leading to a collective excitation of all of the free electrons in the particles. As illustrated in Figure 8, the movement
    of the electrons under the influence of the electronic field vector of the incoming light leads to a dipole excitation
    across the particle sphere, the positive polarization charge acting as a restoring force, which makes the electrons oscillate.
    Thus, the electron density within a surface layer, the thickness of which is about equal to the screening length
    of a few angstroms, oscillates, whereas the density in the interior of the particle remains constant [“surface plasmon”
    (SP)]. From one up to three SP bands may be observed, corresponding to three polarizability axes of the metallic
    nanoparticles. A prerequisite for the formation of an intense plasmon absorption band is that 12 (the imaginary part of the
    dielectric constant of the metal) is not too large [11]. Silver particles have the unique property that the excitation of the
    collective oscillation (plasmon absorption,  = 380 nm) and of the interband transitions ( = 320 nm) occur in separate
    wavelength regimes. The plasmon resonances possessed by gold and copper are in the visible (Au 520 nm; Cu 570 nm),
    however, these resonances are superimposed by interband transitions.
    In theory, the absorption spectra of metal particles smaller than the wavelength of incident light can be calculated
    on the basis of the Mie equation for nanoparticles whose metallic dielectric function is known and which
    are embedded in a medium of known dielectric constant [413–416]. The position and magnitude of the surface plasmon
    absorption band are intensively dependent on the size of the particles, the refractive index of the solvent,
    and the degree of aggregation. The surface plasmon resonance should shift slightly to high energy, and broaden
    somewhat as the particle size is decreased; meanwhile, the intensity of absorption decreases remarkably until it is essentially
    unidentifiable for crystallites of less than 2 nm effective diameter [417, 418]. For example, a symmetric and
    comparatively narrow absorption peak at a shorter wavelength is usually indicative of relatively small, monodisperse,
    and spherical metal nanoparticles. However, it has been demonstrated both theoretically [419–422] and experimentally
    [423, 424] that the SP resonances of the coinage metal nanoparticles depend much more sensitively on the particle
    shapes than on the sizes. Typically, in the case of gold nanorods, the absorption spectra are characterized by the
    dominant SPl band (at longer wavelength, ca. 620–900 nm), corresponding to longitudinal resonance and a much weaker
    transverse resonance than the SPt band (at shorter wavelength, ca. 520 nm).
    In general, for bimetallic Ag/Au nanoparticles, the absorption bands of alloys fall between the maxima of the
    respective constituent surface plasmon absorption bands, and core–shell structures manifest themselves in two distinct
    bands [413, 425]. Morphologies and absorption spectra of composite Ag/Au nanoparticles were, however, found
    to depend on the deposited metal atoms/surface ratio in a less than straightforward manner [426]. In contrast, several
    experimental results show that what is observed in the core– shell structured nanoparticles is only the plasmon absorption
    of pure metal of the core or shell constituent, probably due to particles deviating from the perfect core–shell model
    [427, 428]. The wavelength of the plasmon resonance of the nanoshells that are the other kind of colloidal particles,
    consisting of a small dielectric core covered by a thin metallic shell, can be tunable in the visible and near-infrared
    regions by varying the core/shell radii. This allows for the design of nanoshells with plasmon resonance across a spectral
    range from about 600 to 2500 nm [429]. The scattering from nanoshells adheres to the Mie scattering theory
    [429–431].
    The efficiency for the absorption and scattering of light by metal nanoparticles can surpass that of any molecular
    chromophore.
    In addition, both absorption and scattering properties can be considerably altered by surface
    modification or by electronic coupling between individual nanoparticles. Together with an expectional resistance
    to photodegeneration, such favorable optical features are stimulating the development of new applications in analytical
    chemistry and in photophysics, making metal colloids attractive components for diagnostic, electronic, and photonic
    devices.

    from Noble Nano Particles

  2. #11
    Mustafa Umut Sarac's Avatar
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    I have a full basic and effective recipe to prepare collodial gold and silver but I forgot which books binder I wrote to I will find in few days and anyone would be able to prepare them. For Gum, Dye Transfer, Autochrome, Inkjet or others , anyone could be able to manipulate the variables first on small batches and than more.

    Umut
    Last edited by Mustafa Umut Sarac; 11-09-2012 at 09:15 PM. Click to view previous post history.

  3. #12
    Mustafa Umut Sarac's Avatar
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    There is an color changing ink on new american banknote , this is an ink which contains collodial gold or silver. There is an extensive list of patents at google patents and uspto.gov.

    Particles goes to 100 to 1 nanometer diameter or so , they tend to change their colors with receiving photon, wait, resonate and release an new color. This new color is different than what we see than bigger particles .

    Gold tend to go in fuschia color and can be manipulated to wide range of colors including deep reds to purples and green.
    Silver goes to yellow and orange colors,green , blue..
    Platin goes to brown when it is in nanoparticle state.
    Turkovich method is the best to manufacture them. But it needs several heating and cooling steps plus rules while adding new chemicals to solution plus stirring rules.
    I will find the recipe of these today. You can google collodial gold silver ink and recieve many patents.
    Last edited by Mustafa Umut Sarac; 11-09-2012 at 09:13 PM. Click to view previous post history.

  4. #13
    Mustafa Umut Sarac's Avatar
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    Medieval Stained Glass and Nanoparticle Colors

    Click image for larger version. 

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  5. #14
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    I used some Colloidal Silver for a persistent infection of the outer ear -- it worked immediately.
    At least with LF landscape, a bad day of photography can still be a good day of exercise.

  6. #15
    Mustafa Umut Sarac's Avatar
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    From Arthur Nash Notebooks of Tiffany Co.

    Arthur Nash was a very important glass maker from England and Louis C. Tiffany invited him to US to formulate new glasses and colors at late 19th century. He and his son developed many formulas and pioneered at Glass making and coloring technology. He always kept his secrets in a little notebook and never revealed the formulas to Tiffany.

    His notebooks sold to Corning and opened to public.

    cobalt oxide blue , uranium oxide yellow , iron oxide green , and he used manganese , arsenic , silver nitrate , potash nitrate , platin , palladium , rb , and many more for their own colors or plasmon colors.

    Umut

  7. #16
    Randy Moe's Avatar
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    Umut,

    Please keep up the good work!

    Thank you!

  8. #17
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    Very interesting indeed!

  9. #18

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    Quote Originally Posted by stormpetrel View Post
    Very interesting indeed!
    Yes this is. A good compilation Umut. I did some work with photonic crystals tuned to length here http://microphonium.blogspot.com/201...d-patents.html

    One of the intriguing things would be to use these as part of a new color system - perhaps a direct positive color system, that could be electronically activated, instead of with chemicals.

  10. #19
    Mustafa Umut Sarac's Avatar
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    Liquid gold compositions
    EP 1244753 B1
    ÖZET (metnin alındığı doküman: WO2001040392A1)
    The present invention relates to a liquid gold composition comprising a gold lustre and an effective amount of an acrylate polymer of the formula (I): -[-CH2-C(R)-]-n, C(O)-O-Y; where R = H or a C1-C4 alkyl group, Y = a C5-C40 hydrocarbyl group, which is monocyclic, bicyclic or tricyclic, which may be further carry ring substituents and n = an integer representing the number of repeat units in the polymer. The gold composition can be used to decorate substrate surfaces and the decoration applied upon firing forms an excellent, bright film of gold on the decorated substrate surface.

    HAK TALEPLERI
    A liquid gold composition comprising a gold lustre and 0.05 to 50% by weight of an acrylate polymer of the formula:


    where
    R = H or a C 1-C4 alkyl group,
    Y = a C5 - C40 hydrocarbyl group, which is monocyclic, bicyclic or tricyclic, which may be further carry ring substituents, and
    n = an integer representing the number of repeat units in the polymer.
    A composition according to Claim 1 wherein the gold lustre is a hydrocarbyl mercaptide of gold and is of the formulae:
       Au-S-CH2R1, wherein R1 = alkyl Au-S-CH(R2)R3, wherein each of R 2 and R3 = the same or different alkyl or aryl group (secondary thiols)
    Au-S-CR4R5 R6, wherein each of R4, R5 and R6 = the same or different alkyl or aryl group (tertiary thiols)
    Au-S-R7 wherein R7 = aryl group or a substituted aryl group (aromatic thiols).
    AuSCHRCO2R where R= H, alkyl or aryl and R'=H, alkyl or aryl

    A composition according to Claim 2 wherein the hydrocarbyl group in the gold mercaptides are selected from alkyl, cycloalkyl, aryl and aralkyl groups, and the halo-, amino-, and carboxylic acid- substituted derivatives thereof.

    A composition according to Claim 2 or 3 wherein the hydrocarbyl groups in the mercaptide is selected from methyl, ethyl, isopropyl, butyl, sec.-butyl, isobutyl, tert-butyl, heptyl, octyl, isooctyl, 2-ethyl hexyl, di-isobutylmethyl, nonyl, tert-nonyl, decyl, tert-decyl, undecyl, tert-undecyl, dodecyl, tert-dodecyl, tridecyl and octadecyl, cyclobutyl, cyclopentyl, cyclohexyl, dicyclohexylmethyl, phenyl, naphthyl, phenanthryl, benzyl, methylphenyl, 2-phenyl ethyl, 4-phenyl butyl, p-tert.-butylphenyl, o-methyl-p-tert.-butylphenyl, pinanyl, mixed methylphenyl, mixed dimethylphenyl, mixed dibenzylmethyl, p-chlorophenyl, pentachlorophenyl, o-carboxy-phenyl and o-aminophenyl groups.

    A composition according to Claim 1 wherein the gold lustre is a gold sulpho-resinate.

    A composition according to Claim 1 or 5 wherein the gold lustre is a gold sulpho-resinate obtained from a gold (III) salt and a sulphurised terpene, the terpene component of which may be naturally occuring

    A composition according to any one of the preceding Claims wherein the cyclic hydrocarbyl group Y is a terpenyl group.

    A composition according to any one of the preceding Claims wherein the terpenyl group is derivable from a terpene which is a natural, non-aromatic constituent of an essential oil, containing carbon, hydrogen and optionally oxygen, and/or a synthetic compound which is very closely related to the natural terpenes.

    A composition according to Claim 7 wherein the terpenyl group is derived from a terpene is selected from monoterpenes (10 carbons - two isoprene units), sesquiterpenes (15 carbons), diterpenes (20 carbons), triterpenes (30 carbons) and tetraterpenes (40 carbons).

    A composition according to Claim 9 wherein the terpenyl group is derived from a bicyclic monoterpene (10 carbons).

    A composition according to Claim 10 wherein the terpenyl group is a bicyclic monoterpenyl group selected from bornyl, isobornyl, thujyl, fenchyl, pinocamphyl and isopinocamphyl groups.

    A composition according to any one of the preceding Claims wherein the polymers of formula (I) have an average molecular weight in the range from 2,000 to 600,000.

    A composition according to any one of the preceding Claims wherein the polymer of formula (I) is poly(isobornyl methacrylate).

    A composition according to Claim 13 wherein the polymer has an average molecular weight in the range from 500,000-600,000.

    A composition according to claim 13 wherein the polymer has an average molecular weight of approximately 100,000.

    A composition according to any one of the preceding Claims wherein said composition contains in addition a solvent capable of forming a substantially homogeneous mixture with the gold lustre and the polymer so as to form a liquid or a smooth paste.

    A composition according to Claim 16 wherein the solvent is selected from ketones, aliphatic hydrocarbons, aromatic hydrocarbons, alkyl acetates, glycol ethers, terpenes, natural oils and waxes.

    A composition according to any one of the preceding Claims wherein said composition contains in addition a gold flux.

    A composition according to Claim 18 wherein the gold flux is selected from salts or resinates of antimony, bismuth, boron, cadmium, cerium, chromium, cobalt, copper, iridium, lead, rhodium, silicon, silver, tin, titanium, vanadium and zirconium.

    A composition according to Claim 18 or 19 wherein the amount of flux added to the compositions is in the range from about 0.01 to 10 % by weight of the total composition.

    A method of decorating a substrate surface said method comprising applying a composition comprising a gold lustre and 0.05 to 50 % by weight of an acrylate polymer of the formula:


    where
    R = H or a C 1-C4 alkyl group,
    Y = a C5 - C40 hydrocarbyl group, which is monocyclic, bicyclic or tricyclic, which may be further carry ring substituents, and
    n = an integer representing the number of repeat units in the polymer in a solvent, and heat-treating the resultant decorated substrate to cure the decoration on the substrate surface.
    A method according to Claim 21 wherein the composition is applied on the substrate surface by one or more methods selected from brush coating, spraying, stippling, stenciling, decalomania, direct and offset printing, indirect screen-printing, direct hot- or cold-printing and ink-jet printing techniques.

    A method according to Claim 21 or 22 wherein the substrate on which the composition is applied is selected from the group consisting of glass, earthenware, bone china, porcelain, silicate materials, metals, quartz, carbon, mica, plastics, laminates, wood, paper, textiles and leather.

    A method according to any one of the preceding Claims 21-23 wherein the composition applied to the substrate surface is as claimed in any one of the preceding Claims 2-20.

  11. #20
    Mustafa Umut Sarac's Avatar
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    AÇIKLAMA
    [0001] The present invention relates to new and improved liquid gold compositions, a method of preparation therefor and use thereof for decorating substrates.
    [0002] Liquid gold compositions have been known in the art and used for gilding and decorating substrates for a long time. Traditional liquid gold compositions contain gold sulpho-resinates in combination with natural resinous materials (by Boudnikoff, Compt. Rend., 196, 1898 (1933) and by Chemnitius, J. Prakt. Chem., 117, 245 (1927)). The gold sulpho-resinates are prepared by the reaction of a gold chloride solution with a sulphurised terpene. These are then diluted with natural oils such as lavender, rosemary and pine oils. Rosin and asphalt resins are added to thicken the compositions so that they are suitable for decorating, gilding or printing applications. Furthermore, small amounts of salts or resinates of metals such as rhodium, bismuth, chromium etc are also added as fluxes to these compositions to improve the lustre of the gold in the fired product and also to improve the adhesion of the gold applied to the substrate upon firing. In preparing other compositions, various gold mercaptides have been used. For instance, US-A-2490399 describes the use of gold mercaptides of cyclic terpenes but does not provide any structure for the resultant mercaptide. Again, the mercaptide of gold prepared from thio-borneol has been described in the Journal of the Society of the Chemical Industry, Japan, 38, Supplement 617B (1935) by Nakatsuchi although this reference makes no mention of the possibility of using such compounds in decorating or gilding compositions. According to US-A-3163665, the gold thiolates derived from cyclic terpenes have the disadvantage of requiring relatively high firing temperatures, thereby limiting their use on substrates such as glass, ceramics etc. and consequently recommends the use of non-terpenoid gold secondary mercaptides. Similarly, US-A-3245809 claims and describes the use of a liquid gold decorating composition comprising a nuclear-substituted gold aryl mercaptide wherein the sulphur is attached directly to the aryl nucleus which is already substituted by an alkyl group in solution in an organic vehicle and a gold flux. The specific aryl mercaptides disclosed include gold p-tert.-butylphenyl mercaptide prepared from p-tert.-butylbenzenethiol and aurous chloride. The fluxes used are said to contain small amounts of salts or resinates of rhodium or iridium to improve the continuity and brilliance of the gold film and the only other component, apart from the vehicle (solvent), is rosin dissolved in oil of turpentine. No synthetic polymeric thickeners are mentioned in these compositions.
    [0003] More recently, US-A-5328769 states that the conventional isooctyl- and tert.-dodecyl-gold thioglycolates are not satisfactory for use in gilding preparations for decorating ceramics because the drying time for such preparations is very long. This document also states that gold (I) bornyl mercaptide (described in US-A-4221826) proved advantageous in the production of integrated electronic circuits but that such compounds "have the disadvantage of a partially very unpleasant odour which becomes particularly noticeable in a disturbing manner when the gold preparations are applied by heat". Thus, instead, this reference claims and describes a method of gilding solid bases, by applying a gold preparation comprising a gold mercaptocarboxylic acid ester on to a solid base followed by firing. The "gold preparation" also contains fluxing agents including in particular, sulphoresinates, resinates, naphthenates, carboxylates, and dithiocarbamates of the elements B, Si, V, Cr, In, Sn, Pb, Bi and Rh. These compositions are also stated to contain one or several resins from the series of wood resins and synthetic resins (e.g., hydrocarbon resins, polyacrylates and polymethacrylates). However, no preparations containing these synthetic resins are described and no particular benefit or advantage is said to accrue by the use of such synthetic resins.
    [0004] Thus, the liquid gold compositions typically involve the use of either (i) a gold mercaptide compound, or, (ii) a gold sulpho-resinate, in combination with natural resins (e.g. rosin or colophony, often in their sulphided form, or, asphalt) and some synthetic resins such as e.g. phenol-aldehyde resins. The gold sulpho-resinates of the present invention in turn can be obtained from a gold (III) compound or gold (I) salts or compounds and a sulphurised terpene, the terpene component of which may be naturally occuring. These compositions may have overcome some of the traditional problems such as e.g. adhesion, drying, odour etc. However, they still have one or more of the following disadvantages:
    [0005] Unsatisfactory application of ink onto substrate; undesirable changes in viscosity during application; formation of defective films on application to the substrate prior to firing; dewetting of ink on substrate (often caused by sensitivity of ink to dust particles) leading to pinholing; formation of defective films having 'black spots' on firing which cannot be envisioned prior to firing; poor adhesion of the gold film on to the substrate; and observation of poor colour, usually red, on the reverse of transparent substrates such as e.g. glass.
    [0006] It has now been found that the performance of the liquid gold compositions in all the above aspects can be substantially improved by choice of a specific synthetic polymer for thickening such compositions.
    [0007] Accordingly, the present invention is a liquid gold composition comprising a gold lustre and an effective amount of an acrylate polymer of the formula:

    where
    R = H or a C1-C4 alkyl group,
    Y = a C5 - C40 hydrocarbyl group, which is monocyclic, bicyclic or tricyclic, which may be further carry ring substituents. and
    n = an integer representing the number of repeat units in the polymer.
    [0008] By the expression "gold lustre" as used herein and throughout the specification is meant a derivative of gold which may be a sulpho-resinate, hydrocarbyl (such as e.g. alkyl or aryl) mercaptide, or a mercaptocarboxylic acid or an ester thereof. The term gold sulpho-resinate in the context of the present invention means a gold compound formed from a gold (III) compound or a gold (I) compound and sulphurised resin group. As mentioned previously, the gold sulpho-resinates can be obtained from a gold (III) salt and a sulphurised terpene, the terpene component of which may be naturally occuring. Specific examples of such mercaptide compounds include:
    a. hydrocarbyl gold mercaptides of the formulae Au-S-CH2R1, wherein R1 = alkyl
    Au-S-CH(R2)R3, wherein each of R 2 and R3 = the same or different alkyl or aryl group (secondary thiols)
    Au-S-CR4R5 R6, wherein each of R4, R5 and R 6 = the same or different alkyl or aryl group (tertiary thiols)
    Au-S-R7 wherein R7 = aryl group or a substituted aryl group (aromatic thiols).
    Au-SCHR-C02R' where R = H, alkyl, aryl and R' =H, alkyl, aryl
    [0009] More specifically, references to the hydrocarbyl groups, such as e.g. alkyl or aryl groups, in the formulae above includes within its scope the respective groups selected from alkyl, cycloalkyl, aryl and aralkyl groups, and any substituted derivatives thereof. For example the substitued derivitives may be halo, amino, carboxylic acid or ester groups. Specifically, the hydrocarbyl groups in the mercaptide may be any one of methyl, ethyl, isopropyl, butyl, sec.-butyl, isobutyl, tert-butyl, heptyl. octyl, isooctyl, 2-ethyl hexyl, di-isobutylmethyl, nonyl, tert-nonyl, decyl, tert-decyl, undecyl, tert-undecyl, dodecyl, tert-dodecyl, tridecyl and octadecyl, cyclobutyl, cyclopentyl, cyclohexyl, dicyclohexylmethyl, phenyl, naphthyl, phenanthryl, benzyl, methylphenyl, 2-phenyl ethyl, 4-phenyl butyl, p-tert.-butylphenyl, o-methyl-p-tert.-butylphenyl, pinanyl, mixed methylphenyl, mixed dimethylphenyl, mixed dibenzylmethyl, p-chlorophenyl, pentachlorophenyl, o-carboxy-phenyl and o-aminophenyl groups. These mercaptides can be prepared by admixing the appropriate hydrocarbyl mercaptan with a gold salt suitably a halogenated auric salt such as auric bromide. auric chloride. auric iodide, potassium bromoaurate or potassium iodoaurate as described in US-A-3245809.
    [0010] The acrylate polymers present in the compositions of the present invention are of the formula:

    where
    R = H or a C1-C4 alkyl group,
    Y = a C5 - C40 hydrocarbyl group, which is monocyclic, bicyclic or tricyclic and which may be further carry ring substituents, and
    n = an integer representing the number of repeat units in the polymer.
    [0011] Cyclic hydrocarbyl groups representing Y are suitably terpenyl groups derivable from a terpene and the term "terpene" as used herein and throughout the specification is meant to describe a cyclic compound which is a natural, non-aromatic constituent of an essential oil, containing carbon, hydrogen and optionally oxygen, and/or synthetic compounds which are very closely related to these natural terpenes. These terpenes can be selected from the following classes based on the number of isoprene units within the structure: monoterpenes (10 carbons - two isoprene units), sesquiterpenes (15 carbons), diterpenes (20 carbons), triterpenes (30 carbons) and tetraterpenes (40 carbons). Of these. the group Y is preferably a terpenyl group derived from a bicyclic monoterpene (10 carbons). More specifically, examples of bicyclic monoterpenyl groups include bornyl, isobornyl, thujyl, fenchyl, pinocamphyl and isopinocamphyl groups.
    [0012] Such polymers can be prepared by solution or suspension polymerisation reaction of the desired monomer and a suitable initiator under dry anaerobic reaction conditions. The polymers of formula (I) suitably have an average molecular weight in the range from 2.000 to 600,000, preferably from 30,000 to 600,000, more preferably from 50,000 to 200,000.
    [0013] An example of a polymer of formula (I) is poly(isobornyl methacrylate) which in turn can be made from the corresponding isobornyl methacrylate monomer and having an average molecular weight in the range from 500,000-600,000. Such polymers are commercially available (ex Aldrich Chemicals).
    [0014] The amount of the polymer (I) in the compositions of the present invention is suitably in the range from 0.05 to 50% by weight, preferably from 0.5 to 30% by weight, typically 1 to 10% by weight of the total composition. The amount of the polymer (I) used may vary within these ranges depending upon the molecular weight thereof and the method used for the application of the liquid gold composition on the substrate.
    [0015] The compositions of the present invention suitably contain in addition a solvent to provide a vehicle for applying the gold composition onto a substrate. The solvent should be such that it is capable of forming a substantially homogeneous mixture with the gold lustre and the polymer so as to form a liquid or a smooth paste. Thus, the solvent chosen should be such that it is commensurate with the desired physical properties in the composition such as e.g. oilness, viscosity, evaporation rate, surface tension and tack, depending upon the manner in which the composition is to be applied to the substrate surface. Suitable examples of such solvents include ketones, aliphatic hydrocarbons, aromatic hydrocarbons. alkyl acetates, glycol ethers, terpenes, natural oils and waxes. More specifically, these may be one or more of the following: methyl ethyl ketone, cyclohexanone, ethyl acetate, ethyl lactate, butyl lactate, amyl acetate, cellosolve, butanol, cyclohexanol, propylene glycol butyl ether, propylene glycol phenyl ether, dipropylene glycol dimethyl ether, propylene glycol methyl ether acetate, toluene, xylene. petroleum ether, terpenes such as pinene, dipentene, dipentene oxide, natural oils such as lavender, rosemary, aniseed, sassafras, wintergreen, fennel, and turpentine. Various other subsidiary resins such as rosin, asphalt, colophony, poly(terpene), phenolformaldehyde resins and the like may also be present in the compositions of the present invention.
    [0016] The compositions of the present invention may contain in addition gold fluxes which are small amounts of metal salts or resinates and these determine the behaviour of the gold film during application on the substrate and subsequent firing thereof at elevated temperature. The specific choice of flux will be determined not only by the aforementioned conditions but also by the substrate upon which the composition is to be applied, the method of application as well as the need to provide lustre to the metal film applied on the substrate. Examples of fluxes that may be used include salts or resinates of antimony, bismuth, boron, cadmium, cerium, chromium, cobalt, copper, iridium, lead, rhodium, silicon, silver, tin, titanium, vanadium and zirconium. The fluxes also improve the adhesion of the gold metal film on the substrate and provide resistance to abrasion. The fluxes achieve these functions by initially melting and then forming a thin, protective, transparent film on the metal film during the firing process. Of these, fluxes containing salts or resinates of rhodium and/or iridium are most preferred.
    [0017] The amount of flux added to the compositions of the present invention is suitably in the range from about 0.01 to 10 % by weight, preferably from about 0.05 to 5.0 % by weight of the total composition.
    [0018] The substrate surface on which the compositions of the present invention are applied may be suitably of relatively refractory materials and are preferably selected from the group consisting of glass, earthenware, bone china, porcelain, silicate materials, metals, quartz, carbon, mica and the like.
    [0019] The compositions of the present invention may be applied on the substrates by any of the known application methods. For instance, they may be applied by simple brush coating, spraying, stippling, stenciling, decalomania, direct and offset printing, indirect screen-printing, direct hot- or cold-printing or ink-jet printing techniques.
    [0020] Thus, according to a further embodiment the present invention is a method of decorating substrate surfaces, said method comprising applying a composition comprising a gold lustre and the polymer (I) in a solvent, and heat-treating the resultant substrate to cure the decoration on the substrate surface.
    [0021] As indicated above, once the composition of the present invention in a solvent is applied as a decoration on a substrate surface, the decoration is suitably cured by heat-treating the decorated substrate at elevated temperature. The heat-treatment temperatures used will depend upon the nature of the gold lustre used, the solvent used and the amount of the polymer (I) used, although more importantly, it will depend upon the substrate surface upon which the decoration is applied. Thus, for refractory substrates, heat-treatment/firing temperatures may vary over a wide range from about 300-1300C, preferably from about 500-900C, typically from about 550-900C. Temperatures towards the upper end of the ranges specified above e.g. around 900C may be required for substrates such as porcelain.
    [0022] A feature of the compositions of the present invention is that the use of the specific polymers (I) showed excellent compatibility with the gold lustres used. Moreover, on firing, the major problem of 'black spot' formation with conventional compositions was no longer observed. Also, on glass, reverse colour is improved over that of currently available compositions for this purpose. Analogous formulations prepared using commercially available polymers corresponding to polymer (I) but in, which the terpenyl group Y is replaced by a relatively simple alkyl group, such as eg methyl, ethyl or butyl groups, did not show similar improvement in the decorative films formed.
    [0023] The compositions and process of the present invention are further illustrated with reference to the following Examples:
    EXAMPLES:
    Bright gold preparations
    [0024] All composition data is in % by weight and all firing temperatures are in C. The gold sulpho-resinates used are available from Johnson Matthey PLC and the silver sulpho-resinates were prepared from silver and sulphurised balsam. A solution of poly(isobomyl methacrylate) was prepared in the stated solvent at various concentrations as specified in each Example below. All formulations were prepared to give 'a concentration of 10% wt Au. This was then used to prepare the following liquid gold formulations. All formulations were prepared to give a concentration of 10wt%Au.
    EXAMPLE 1
    [0025]
    18.3 Au(SC6H4-p-CMe3) (prepared according to the method described in US-A-3,245,809)
    40 Poly(isobornyl methacrylate) (ex Aldrich. MW 550.000) as a 30% by weight solution in cyclohexanone
    4 Rh-ethyl-hexanoate dissolved in cyclohexanone (0.12% Rh)
    37.7 Xylene
    100
    Comparative Test
    (not according to the invention):
    [0026]
    18.3 Au(SC6H4-p-CMe3) (prepared according to the method described in Example 1(F) of US-A-3,245,809)
    40 Poly(butyl methacrylate) (NeocrylB804, ex Zeneca Resins) as a 30% by weight solution in cyclohexanone
    4 Rh-ethyl-hexanoate dissolved in cyclohexanone (0.12% Rh)
    37.7 Xylene
    100
    [0027] Each of the above two formulations were gilded onto ceramic ware, and fired at 865C over a 1 hour cycle. The formulation of Example 1 gave bright golden films free of film defects whereas the formulation of the Comparative Test gave poor quality films.
    EXAMPLE 2
    [0028]
    30.86 Gold sulpho-resinate
    40 Poly(isobornyl methacrylate) (ex Aldrich Chemicals) as a 20% by weight solution in cyclohexanone
    4 Rh-ethyl-hexanoate dissolved in cyclohexanone to a final concentration of 3% Rh
    0.54 Cr Nuosyn5 to a final concentration of 7.45% Cr2O3
    3.67 Bismuth octoate lustre to a concentration of 10% Bi2O3
    20.93 Rosemary oil
    100
    [0029] The formulation was applied to china and porcelain by brush over a large area. Upon firing, it gave a bright gold film of similar colour to commercial golds with no film defects (ie black spots) observed in the film.
    EXAMPLE 3
    [0030] The process of Example 2 was repeated except that sulphided colophony resin was used instead of the poly(isobomyl methacrylate). Bright films, with film defects were obtained upon application and subsequent firing.
    EXAMPLE 4
    [0031]
    18.3 Au(SC6H4-p-CMe3)
    29.9 -pinene
    21.2 Silver sulpho-resinate solution (2% wt Ag) in form
    2.4 Anethol
    1.2 Rosemary oil
    10 Dipentene
    10 Poly(isobornyl methacrylate) as a 20% wt cyclohexanone solution
    6 Poly(isobomyl methacrylate) as a 20% wt solution in lavender oil
    1 Rh-ethyl-hexanoate dissolved in cyclohexanone (0.12% Rh)
    [0032] The formulation was applied onto a Koelner Stange glass at 580C and upon firing bright films free of film defects were obtained.
    EXAMPLE 5
    [0033]
    18.3 AuSC6H4-p-CMe3
    40 30% wt Poly(isobornyl methacrylate) (100,000 mwt supplied by Scientific Polymer Products Inc.) solution in cyclohexanone
    4 Rh-hexanoate dissolved in cyclohexanone (0.12%Rh)
    37.7 Xylene
    [0034] The formulation above was gilded onto ceramic ware , fired at 840°C over 1hr. Bright gold films free of defects were produced.

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