A liquid toner includes a carrier liquid, and toner particles including a thermoplastic resin and a metallic colorant dispersed in said thermoplastic resin, the toner particles being dispersed in the carrier liquid. The liquid toner enables formation of printed images having a metallic sheen using a liquid toner imaging process.

1. Field of Invention
This invention relates to a method for producing a liquid toner or developer composition, more particularly a liquid toner or developer composition comprising metallic particles. The invention also relates to liquid toner or developer compositions made by such a process, and the use of such liquid toner or developer compositions in electrostatographic imaging processes.
2. Description of Related Art
A latent electrostatic image can be developed with toner particles dispersed in an insulating non-polar liquid. Such dispersed materials are known as liquid toners or liquid developers. A latent electrostatic image may be produced by providing a photoconductive layer with a uniform electrostatic charge and subsequently discharging the electrostatic charge by exposing it to a beam of radiant energy. Other methods are also known for forming latent electrostatic images such as, for example, providing a carrier with a dielectric surface and transferring a preformed electrostatic charge to the surface. After the latent image has been formed, it is developed by colored toner particles dispersed in a non-polar liquid. The image may then be transferred to a substrate or receiver sheet, such as paper or transparency.
Insufficient particle charge can result in poor image quality and also can result in poor transfer of the liquid developer or solids thereof to paper or other final substrates. Poor transfer can, for example, result in poor solid area coverage if, for example, insufficient toner is transferred to the final substrate, and can also cause image defects such as smears and hollowed fine features. Conversely, overcharging the toner particles can result in low reflective optical density images or poor color richness or chroma since only a few very highly charged particles can discharge all the charge on the dielectric receptor, causing too little toner to be deposited.
Useful liquid toners comprise thermoplastic resin toner particles and a dispersant non-polar liquid. Generally, a suitable colorant, such as a dye or pigment, is present in the toner particles. The colored toner particles are dispersed in a non-polar liquid that generally has a high volume resistivity, such as in excess of 109 xcexa9-cm, a low dielectric constant, for example below 3.0, and a high vapor pressure. Generally, the toner particles have an average particle size (by area) or diameter of less than 7 microns as measured with a Horiba CAPA 700 Particle Sizer.
Various methods are known in the art for producing liquid toners and developers. The conventional process for producing such liquid toners involves a two-step batch process, wherein the first step involves a hot step where the non-polar liquid and molten resin are melt mixed with pigment and other additives, and the second step involves a cold step where the molten contents are cooled to cause solidification and formation of particles in the non-polar liquid.
For example, one process of making such liquid toners is described in U.S. Pat. No. 4,760,009, the entire disclosure of which is incorporated herein by reference, which describes such a two step process. According to the patent, the process comprises a first step of dispersing a thermoplastic resin, a non-polar liquid having a Kauri-butanol value of less than 30, and optionally a colorant at an elevated temperature in a vessel by means of moving particulate media. The temperature in the vessel is maintained at a temperature sufficient to plasticize and liquefy the resin and below that at which the non-polar liquid boils and the resin and/or colorant decomposes. In a second step, the dispersion is cooled to permit precipitation of the resin out of the dispersant. The particulate media is maintained in continuous movement during and subsequent to the cooling. Both steps are carried out in a suitable vessel, such as an attritor, a heated ball mill, or a heated vibratory mill, equipped with particulate media for dispersing and grinding. The result is described as toner particles having an average by area particle size of less than 10 xcexcm and a plurality of fibers. Following the second step, the dispersion of toner particles can be separated from the particulate media.
The patent describes that useful thermoplastic resins or polymers that are able to form fibers and that can be used in the production method include ethylene vinyl acetate copolymers, copolymers of ethylene and an xcex1,xcex2-ethylenically unsaturated acid, copolymers of ethylene/acrylic or methacrylic acid/alkyl (C1 to C5) ester of methacrylic or acrylic acid, polyethylene, isotactic polypropylene (crystalline), ethylene ethyl acrylate series, and ethylene vinyl acetate resins.
Other methods for forming liquid toners, which are generally variants of the above process, are described, for example, in U.S. Pat. Nos. 5,604,075, 5,688,624, 5,783,349 and 5,866,292, the entire disclosures of which are incorporated herein by reference. For example, U.S. Pat. No. 5,604,075 describes a process for the preparation of liquid developers with reduced fines, which comprises heating a liquid developer comprised of thermoplastic resin, pigment, charge adjuvant, liquid hydrocarbon, and optional charge director. The heating is accomplished at about 5xc2x0 C. below the melting point of the thermoplastic resin, which heating enables the fines comprised of the developer components, and of a size diameter of from about 0.1 to about 0.4 micron, to be reduced.
Despite the various liquid toners and developers that are available, and the known methods for making such liquid toners and developers, there remains a need in the art for improved liquid toners and developers that provide high print quality, and for methods for producing such liquid toners and developers. This need is particularly evident for liquid toners and developers having a broader spectrum of available custom colors, including metallic colors.
In particular, there is a large market for metallic-colored inks and printing. However, it has been very difficult in the past to provide liquid toners and developers that can provide high quality prints with metallic colors. Accordingly, the present invention provides new and improved liquid toners and developers, that include metallic colorants, and which provide high quality printed images.
More particularly, in embodiments, the present invention provides a liquid toner comprising:
a carrier liquid, and
toner particles including a thermoplastic resin and a metallic colorant dispersed in said thermoplastic resin,
said toner particles being dispersed in said carrier liquid.
In other embodiments, the present invention provides methods for producing such a liquid toner composition, as well as methods for developing an image using such a liquid toner composition.
According to the present invention, a liquid toner or developer composition is provided that includes any of a wide variety of metallic colorants. These liquid toner and developer compositions provide high quality printed images, while exhibiting good properties in terms of image development, transfer of the developed image to a substrate such as paper, and fusing of the image to the substrate.
The liquid toner and developer compositions can be made according to any of the various known techniques, including those in the above-described patents, as will be apparent to those skilled in the art. For example, the liquid toner and developer compositions can be made by the conventional processes including the steps of (1) preparing a colorant/resin mixture, and (2) cold grinding the colorant/resin mixture with addition of a suitable non-polar liquid, to prepare the final liquid toner or developer composition. In embodiments of the present invention, the liquid toner can be dry ground between the above steps (1) and (2) to reduce the particle size of the colorant/resin mixture prior to the cold grinding step, if desired. In other embodiments of the present invention, the liquid toner can be prepared by a single step process whereby the colorant, resin, carrier liquid and other optional additives are mixed together and formed into desired sized particles.
Although the following discussion is based on the conventional two step process, the present invention is not limited thereto. Rather, the various components can be suitable combined according to any desired process.
In the first step of the liquid toner formation process, a thorough melt-mix and dispersion of pigment and/or other additives in the resin material is formed. In embodiments, the pigment can be in any suitable form, including conventional pigments and pigments predispersed in a suitable medium, described in more detail below. This melt-mixing can be performed using any suitable mixing apparatus, including but not limited to an attritor, a heated ball mill, or a heated vibratory mill, equipped with particulate media for dispersing and grinding, or even an extruder or similar processing equipment, which provides a homogeneous or uniform dispersion of the colorant and/or other additives in the resin. In producing the homogeneous dispersion, the desired resin material is melt-mixed with any desired colorant and/or other additives that are to be incorporated into the liquid toner.
The first (melt-mixing) step can be conducted in any suitable processing equipment that will provide the necessary homogeneous dispersion of the colorant and/or other additives in the resin. Thus, although an extruder is preferred, particularly where polyester resins are to be used, other suitable equipment can include a Banbury mill, a 2 roll mill, or a sigma blade mixer. Suitable operating parameters for such mixing equipment can readily be determined by one of ordinary skill in the art based on the various components to be melt-mixed. In the case of an extruder, suitable mixing is obtained, for example, at a mixing temperature of from about 104 to 122xc2x0 C. (220 to 251 xc2x0 F.), melt Oust before the material exits the die) and die temperatures of about 115-117xc2x0 C. (240-243xc2x0 F.), and screw rpm of about 15 rpm with an extrusion pressure of from about 270 to 490 psi. Of course, these are exemplary parameters only, and are not limiting on the present invention.
Suitable additives that can be melt-mixed with the resin material and incorporated into the liquid toner include, but are not limited to, colorants, adjuvants and charge control additives. Other suitable additives, known to those of ordinary skill in the art, can also be incorporated into the liquid toner in known amounts for their known purposes.
According to the present invention, the liquid toner or developer includes at least one metallic colorant. The metallic colorant is preferably of a size, type, and shape that it provides, when mixed into the toner particles, a metallic sheen to a resultant printed image.
Suitable metallic colorants include, but are not limited to, particles of a desired metal to provide the desired color. In embodiments, the metallic colorants can include, but are not limited to, colorants that include, in whole or in part, single or multiple (i.e., mixtures of) elemental metals, single or multiple metal alloys; mixtures of one or more elemental metals and metal alloys, metal compounds such as metal oxides, metal complexes, and the like, or mixtures of one or more of the foregoing, so long as the colorant exhibits the desired metallic appearance effect. However, in embodiments, elemental metals and metal alloys are preferred in terms of their color strength. For example, the colorant can include particles of aluminum, silver, gold, copper, iron, steel such as stainless steel, titanium, brass, bronze, mixtures thereof, and the like. Suitable examples include, but are not limited to, STAPA OFFSET 3000, Rich XM-40, and Pale Gold (each available from Obron-Atlantic, Painesville, Ohio). When metallic particles are used, they are preferably of a suitable particle size to permit dispersion in the liquid toner, while providing desired toner particle sizes. Thus, for example, it is preferred that the metallic particles have an average particle size of less than about 10 microns, preferably from about 1 to about 10 microns, more preferably less than about 9 or about 8 microns or from about 2 or about 3 to about 8 or about 9 microns. However, other sizes and types of particles can be used, if desired.
According to embodiments of the present invention, the metallic colorant can be any suitable shape, including but not limited to spherical particles, flakes, slivers, rods, and the like.
In embodiments of the present invention, the metallic colorant can be included in the toner composition in any suitable or desirable amount, to provide desired toner properties as well as metallic appearance strength. Thus, for example, the metallic colorant can be included in the toner particles in an amount of from about 5 percent to about 50 percent, more preferably from about 5 or about 10 percent to about 25 or about 30 percent, although amounts outside these ranges can be used, if desired.
If desired, the metallic particles used as the metallic colorant can also include a surface coating of an insulating material. This may be desirable, for example, if the metallic colorant would otherwise affect the charging properties of the toner, or where a significant amount of the metallic colorant is otherwise exposed at the surface of the toner particles. When an insulating coating is used, any suitable material can be employed. Preferably, such an insulating coating should be thin with respect to the size of the metallic colorant, so that the color strength and appearance is not adversely affected.
In addition to the metallic colorants, the liquid toner or developer of the present invention can also include, if desired, one or more conventional colorants. The additional colorants can be either incorporated into the same toner particles as the metallic colorant, or they can be incorporated into separate toner particles. Thus, for example, the additional colorant can be incorporated into the same toner particles as the metallic colorant so that each toner particle includes both a metallic colorant and a conventional colorant. Alternatively, the separate colorants can be incorporated into separate toner particles from the metallic colorants, and the resultant toner particles having different colorants can be blended together into the same ink composition. Thus, for example, the liquid toner or developer can include one or more additional colorants, such as process colors (cyan, magenta, yellow, red, blue black and the like) and/or fluorescent colors. The additional colorants can provide metallic colored liquid toners and developers, to provide an even broader possible color gamut.
Suitable colorants for use in embodiments of the present invention can include any of the various colorants, such as pigments or dyes and mixtures thereof. Such colorants are preferably present in the liquid toner to render the resultant developed latent image visible at a desired color strength. The colorant, preferably a pigment, may be present in the liquid toner in an effective amount of, for example, from about 0.1 to about 60 percent, and preferably from about 10 to about 50 percent, and in embodiments more preferably from about 20 to about 40 percent by weight, based on the total weight of solids contained in the liquid toner. Even more preferably, the colorant concentration is from about 20 to about 30 percent by weight, based on the total weight of solids contained in the liquid toner. The amount of colorant used may vary depending on the use of the liquid toner.
Examples of suitable pigments that may be used according to the present invention include, but are not limited to, carbon blacks available from, for example, Cabot Corporation, such as MONARCH 1300(copyright), REGAL 330(copyright) and BLACK PEARLS(copyright), and pigments such as FANAL PFNK(trademark), PV FAST BLUE(trademark), SUNFAST BLUE 15:3, pigments as illustrated in U.S. Pat. Nos. 5,223,368 and 5,254,427, the entire disclosures of which are incorporated herein by reference, other known pigments, mixtures thereof, and the like.
Illustrative examples of magenta pigments include 2,9-dimethyl-substituted quinacridone and anthraquinone, identified in the Color Index as CI 60710, CI Dispersed Red 15, CI Solvent Red 19, and the like. Illustrative examples of suitable cyan pigments include copper tetra-4-(octadecyl sulfonamido) phthalocyanine, X-copper phthalocyanine pigment, listed in the Color Index as CI 74160, CI Pigment Blue, and Anthradanthrene Blue, identified in the Color Index as CI 69810, Special Blue Xo2137, and the like. Illustrative examples of yellow pigments that can be selected include diarylide yellow 3,3-dichlorobenzidene acetoacetanilides, a monoazo pigment identified in the Color Index as Cl 12700, CI Solvent Yellow 16, a nitrophenyl amine sulfonamide identified in the Color Index as Foron Yellow SE/GLN, CI Dispersed Yellow 33, 2,5-dimethoxy-4-sulfonanilide phenylazo-4xe2x80x2-chloro-2,5-dimethoxy acetoacetanilide, Permanent Yellow FGL, and the like. Additional examples of pigments include Normandy Magenta RD-2400 (Paul Uhlich), Sunsperse Quindo Magenta QHD 6040 (Sun Chemicals), Paliogen Violet 5100 (BASF), Paliogen Violet 5890 (BASF), Permanent Violet VT2645 (Paul Uhlich), Heliogen Green L8730 (BASF), Argyle Green XP-111-S (Paul Uhlich), Brilliant Green Toner GR 0991 (Paul Uhlich), Heliogen Blue L6900, L7020 (BASF), Heliogen Blue D6840, D7080 (BASF), Sudan Blue OS (BASF), PV Fast Blue B2G01 (American Hoechst), Sunsperse Blue BHD 6000 (Sun Chemicals), Irgalite Blue BCA (Ciba-Geigy), Paliogen Blue 6470 (BASF), Sudan III (Matheson, Coleman, Bell), Sudan II (Matheson, Coleman, Bell), Sudan IV (Matheson, Coleman, Bell), Sudan Orange G (Aldrich), Sudan Orange 220 (BASF), Paliogen Orange 3040 (BASF), Ortho Orange OR 2673 (Paul Uhlich), Paliogen Yellow 152, 1560 (BASF), Lithol Fast Yellow 0991K (BASF), Paliotol Yellow 1840 (BASF), Novoperm Yellow FG 1 (Hoechst), Permanent Yellow YE 0305 (Paul Uhlich), Lumogen Yellow D0790 (BASF), Sunsperse Yellow YHD 6001 (Sun Chemicals), Suco-Gelb L1250 (BASF), Suco-Yellow D1355 (BASF), Hostaperm Pink E (American Hoechst), Fanal Pink D4830 (BASF), Cinquasia Magenta (DuPont), Lithol Scarlet D3700 (BASF), Tolidine Red (Aldrich), Scarlet for Thermoplast NSD PS PA (Ugine Kuhlmann of Canada), E. D. Toluidine Red (Aldrich), Lithol Rubine Toner (Paul Uhlich), Lithol Scarlet 4440 (BASF), Bon Red C (Dominion Color Company), Royal Brilliant Red RD-8192 (Paul Uhlich), Oracet Pink RF (Ciba-Geigy), Paliogen Red 3871K (BASF), Paliogen Red 3340 (BASF), and Lithol Fast Scarlet L4300 (BASF). Other specific suitable pigments that may be used in the present toners and developers include those set forth below:
Other pigments can also be selected.
Various dyes, including organic dyes, can also be used as the colorant material to color the resin particles. That is, the resin may be treated with any suitable organic dye to impart color to it. When used, the organic dye is preferably dispersible at the molecular level in the resin to provide a molecular dispersion and ensure good distribution, since it would otherwise tend to aggregate and give poor color intensity as well as broadened spectral characteristics. Furthermore, the organic dye should be insoluble in the carrier liquid so that once it is imbibed into the resin, it will not diffuse out into the dispersion medium. In addition, insolubility in the dispersion medium ensures that the background deposits will be minimized, since as noted above, the entire imaging surface may be contacted with the liquid developer during development of the electrostatic latent image and the dye cannot deposit on the background areas of the imaging surface if the dye is insoluble in the liquid phase. Moreover, it is preferred that the dye be water insoluble to ensure permanence of the developed image and to avoid dissolving subsequent to development should the image come into contact with water as may frequently be the case in an office environment with coffee, tea and the like.
When dyes are used in the ink compositions of the present invention, any suitable commercially available dye may be used to impart the desired color characteristics to the ink. In embodiments, preferred dyes are the anionic dyes. Specific examples of anionic dyes include Bemacid Red 2BMN, Pontamine Brilliant Bond Blue A, BASF X-34, Pontamine, Food Black 2, Carodirect Turquoise FBL Supra Conc. (Direct Blue 199, Carolina Color and Chemical), Special Fast Turquoise 8GL Liquid (Direct Blue 86, Mobay Chemical), Intrabond Liquid Turquoise GLL (Direct Blue 86, Crompton and Knowles), Cibracron Brilliant Red 38-A (Reactive Red 4, Aldrich Chemical), Drimarene Brilliant Red X-2B (Reactive Red 56, Pylam, Inc.), Levafix Brilliant Red E-4B (Mobay Chemical), Levafix Brilliant Red E-6BA (Mobay Chemical), Pylam Certified DandC Red #28 (Acid Red 92, Pylam), Direct Brill Pink B Ground Crude (Crompton and Knowles), Cartasol Yellow GTF Presscake (Sandoz, Inc.), Tartrazine Extra Conc. (FDandC Yellow #5, Acid Yellow 23, Sandoz), Carodirect Yellow RL (Direct Yellow 86, Carolina Color and Chemical), Cartasol Yellow GTF Liquid Special 110 (Sandoz, Inc.), DandC Yellow #10 (Acid Yellow 3, Tricon), Yellow Shade 16948 (Tricon), Basacid Black X34 (BASF), Carta Black 2GT (Sandoz, Inc.), Neozapon Red 492 (BASF), Orasol Red G (Ciba-Geigy), Direct Brilliant Pink B (Crompton-Knolls), Aizen Spilon Red C-BH (Hodagaya Chemical Company), Kayanol Red 3BL (Nippon Kayaku Company), Levanol Brilliant Red 3BW (Mobay Chemical Company), Levaderm Lemon Yellow (Mobay Chemical Company), Spirit Fast Yellow 3G, Aizen Spilon Yellow C-GNH (Hodagaya Chemical Company), Sirius Supra Yellow GD 167, Cartasol Brilliant Yellow 4GF (Sandoz), Pergasol Yellow CGP (Ciba-Geigy), Orasol Black RL (Ciba-Geigy), Orasol Black RLP (Ciba-Geigy), Savinyl Black RLS (Sandoz), Dermacarbon 2GT (Sandoz), Pyrazol Black BG (ICI), Morfast Black Conc A (Morton-Thiokol), Diazol Black RN Quad (ICI), Orasol Blue GN (Ciba-Geigy), Savinyl Blue GLS (Sandoz), Luxol Blue MBSN (Morton-Thiokol), Sevron Blue 5GMF (ICI), and Basacid Blue 750 (BASF); Levafix Brilliant Yellow E-GA, Levafix Yellow E2RA, Levafix Black EB, Levafix Black E-2G, Levafix Black P-36A, Levafix Black PN-L, Levafix Brilliant Red E6BA, and Levafix Brilliant Blue EFFA, all available from Bayer; Procion Turquoise PA, Procion Turquoise HA, Procion Turquoise Ho5G, Procion Turquoise H-7G, Procion Red MX-5B, Procion Red H8B (Reactive Red 31), Procion Red MX 8B GNS, Procion Red G, Procion Yellow MX-8G, Procion Black H-EXL, Procion Black P-N, Procion Blue MX-R, Procion Blue MX-4GD, Procion Blue MX-G, and Procion Blue MX-2GN, all available from ICI; Cibacron Red F-B, Cibacron Black BG, Lanasol Black B, Lanasol Red 5B, Lanasol Red B, and Lanasol Yellow 46, all available from Ciba-Geigy; Baslien Black P-BR, Baslien Yellow EG, Baslien Brilliant Yellow P-3GN, Baslien Yellow M-6GD, Baslien Brilliant Red P-3B, Baslien Scarlet E-2G, Baslien Red E-B, Baslien Red E-7B, Baslien Red M-5B, Baslien Blue E-R, Baslien Brilliant Blue P-3R, Baslien Black P-BR, Baslien Turquoise Blue P-GR, Baslien Turquoise M-2G, Baslien Turquoise E-G, and Baslien Green E-6B, all available from BASF; Sumifix Turquoise Blue G, Sumifix Turquoise Blue H-GF, Sumifix Black B, Surnifix Black H-BG, Sunifix Yellow 2GC, Sumifix Supra Scarlet 2GF, and Sumifix Brilliant Red 5BF, all available from Sumitomo Chemical Company; Intracron Yellow C-8G, Intracron Red C-8B, Intracron Turquoise Blue GE, Intracron Turquoise HA, and Intracron Black RL, all available from Crompton and Knowles, Dyes and Chemicals Division; mixtures thereof, and the like.
Dyes that are invisible to the naked eye but detectable when exposed to radiation outside the visible wavelength range (such as ultraviolet or infrared radiation), such as dansyl-lysine, N-(2-aminoethyl)-4-amino-3,6-disulfo-1,8-dinaphthalimide dipotassium salt, N-(2-aminopentyl)-4-amino-3,6-disulfo-1,8-dinaphthalimide dipotassium salt, Cascade Blue ethylenediamine trisodium salt (available from Molecular Proes, Inc.), Cascade Blue cadaverine trisodium salt (available from Molecular Proes, Inc.), bisdiazinyl derivatives of 4,4xe2x80x2-diaminostilbene-2,2xe2x80x2-disulfonic acid, amide derivatives of 4,4xe2x80x2-diaminostilbene-2,2xe2x80x2-disulfonic acid, phenylurea derivatives of 4,4xe2x80x2-disubstituted stilbene-2,2xe2x80x2-disulfonic acid, mono- or di-naphthyltriazole derivatives of 4,4xe2x80x2-disubstituted stilbene disulfonic acid, derivatives of benzithiazole, derivatives of benzoxazole, derivatives of benzimidazole, derivatives of coumarin, derivatives of pyrazolines containing sulfonic acid groups, 4,4xe2x80x2-bis(triazin-2-ylamino)stilbene-2,2xe2x80x2-disulfonic acids, 2-(stilben-4-yl)naphthotriazoles, 2-(4-phenylstilben-4-yl)benzoxazoles, 4,4-bis(triazo-2-yl)stilbene-2,2xe2x80x2-disulfonic acids, 1,4-bis(styryl)biphenyls, 1,3-diphenyl-2-pyrazolines, bis(benzazol-2-yl) derivatives, 3-phenyl-7-(triazin-2-yl)coumarins, carbostyrils, naphthalimides, 3,7-diaminodibenzothiophen-2,8-disulfonic acid-5,5-dioxide, other commercially available materials, such as C.I. Fluorescent Brightener No. 28 (C.I. 40622), the fluorescent series Leucophor B-302, BMB (C.I. 290), BCR, BS, and the like (available from Leucophor), and the like, are also suitable.
In addition, the liquid toners and developers of the present invention can include one or more fluorescent colorants, which can be pigments, dyes, or a mixture of pigments and dyes. For example, suitable fluorescent pigment concentrates are disclosed in U.S. Pat. No. 4,911,830, the entire disclosure of which is incorporated herein by reference, and suitable fluorescent colorants are disclosed in U.S. Pat. No. 4,243,694, the entire disclosure of which is incorporated herein by reference. Suitable inorganic fluorescent pigments can be prepared, for example, by adding trace amounts of activating agents such as copper, silver and manganese to high purity sulfides of heavy metals or alkaline earth metals such as zinc sulfide, which are used as raw materials, and calcining them at a high temperature. Suitable organic fluorescent pigments can be prepared, for example, by dissolving fluorescent dyes in the vehicles of synthetic resins or ones prepared by dyeing the dispersed matters of fine resin particles obtained by emulsion polymerization or suspension polymerization with fluorescent dyes. The synthetic resins can include, but are not limited to, vinyl chloride resins, alkid resins and acrylic resins, and the fluorescent dyes include, but are not limited to, C.I. acid yellow 7, C.I. basic red I and the like.
Although not limited thereto, suitable fluorescent dyes include, but are not limited to, those belonging to the dye families known as rhodamines, fluoresciens, coumarins, napthalimides, benzoxanthenes, acridines, azos, and the like. Suitable fluorescent dyes include, for example, Basic Yellow 40, Basic Red 1, Basic Violet 11, Basic Violet 10, Basic Violet 16, Acid Yellow 73, Acid Yellow 184, Acid Red 50, Acid Red 52, Solvent Yellow 44, Solvent Yellow 131, Solvent Yellow 85, Solvent Yellow 135, solvent Yellow 43, Solvent Yellow 160 and Fluorescent Brightner 61. Suitable fluorescent pigments include, but are not limited to, those available from Day-Glo Color Corp. of Cleveland, Ohio, such as aurora pink T-11 and GT-11, neon red T-12, rocket red T-13 or GT-13, fire orange T-14 or GT-14N, blaze orange T-15 or GT-15N, arc yellow T-16, saturn yellow T-17N, corona magenta GT-21 and GT-17N, and the like.
According to the present invention, because liquid toners typically have a final colorant content of 20 percent by weight or more, it is particularly advantageous to supply the colorant, particularly pigment, in the form of it being predispersed in a suitable carrier such as a resin. Alternatively, the metallic colorant can be provided in the form of a paste, particularly where the metallic particles themselves (such as aluminum) may be considered a health or safety hazard. When the metallic colorant is provided in such forms, which are usually of a high weight percent such as 40, 50, 65 percent or more colorant, the colorant is generally let down to the desired loading level for the liquid toner or developer composition.
Of course, the colorant need not necessarily be provided in the form of a predispersed colorant or paste form. Rather, any suitable colorant material may be used, so long as the colorant concentration in the final liquid toner can be provided to obtain desired print quality, and so long as the colorant material is not incompatible with the extruder mixing operation.
Another optional additional component of the electrostatic liquid developer is an adjuvant, which can include, but is not limited to, polyhydroxy compounds, aminoalcohol, polybutylene succinimides, metallic soaps, aromatic hydrocarbons having a kauri-butanol value of greater than 30, mixtures thereof, and the like. These adjuvants are generally used in an amount of 1 to 1000 mg/g, preferably 1 to 200 mg/g of developer solids. Examples of the various above-described adjuvants include, but are not limited to:
A) polyhydroxy compounds: ethylene glycol, 2,4,7,9-tetramethyl-5-decyn-4,7-diol, poly(propylene glycol), pentaethylene glycol, tripropylene glycol, triethylene glycol, glycerol, pentaerythritol, glyceroltri-12 hydroxystearate, ethylene glycol monohydroxystearate, propylene glycerol monohydroxy-stearate;
B) aminoalcohol compounds: triisopropanolamine, triethanolamine, ethanolamine, 3-amino-i-propanol, o-aminophenol, 5-amino-1-pentanol, tetra(2-hydroxyethyl)ethylenediamine;
C) polybutylene/succinimide: OLOA(trademark)-1200 sold by Chevron Corp.; Amoco 575 having a number average molecular weight of about 600 (vapor pressure osmometry) made by reacting maleic anhydride which in turn is reacted with a polyamine (Amoco 575 is 40 to 45% surfactant, 364 aromatic hydrocarbon, and the remainder oil);
D) metallic soaps: aluminum tristearate; aluminum distearate; barium, calcium, lead and zinc stearates; cobalt, manganese, lead and zinc linoleates; aluminum, calcium and cobalt octoates; calcium and cobalt oleates; zinc palmitate; calcium, cobalt, manganese, lead and zinc naphthenates; calcium, cobalt, manganese, lead and zinc resinates;
E) aromatic hydrocarbons: benzene, toluene, naphthalene, substituted benzene and naphthalene compounds, e.g., trimethylbenzene, xylene, dimethylethylbenzene, ethylmethylbenzene, propylbenzene, Aromatic 100 which is a mixture of C9 and C 10 alkyl-substituted benzenes manufactured by Exxon Corp; and
F) aluminum di-tertiary butyl salicylate (ALOHAS) and similar compounds.
Various other additives, which are known in the art, can also be incorporated into the developers of the present invention. Such additives can be incorporated either into the resin/colorant mixtures, i.e., mixed directly into the toner or developer particles, or can be added as surface agents on the surface of the resin/colorant particles once formed.
When the above additives are to be incorporated into the liquid toner, it is preferred that they be added with the resin material and preferably in the first mixing step. This permits the additives to be dispersed directly and uniformly into the resin particles. In embodiments of the present invention, it is particularly preferred that at least the colorant be added with the resin material in the first mixing step, and it is particularly preferred that all of the additives, except for the non-polar liquid, be added with the resin material in the first mixing step. However, in other embodiments, some of the additives can be added at earlier or subsequent stages of the toner preparation process.
According to the present invention, any suitable resin can be used as the resin material, including polyester resins and non-polyester resins. Suitable examples of such polyester resins include, but are not limited to, polyester, particularly the SPAR polyesters, which are commercially available, and are described in U.S. Pat. No. 3,590,000, the entire disclosure of which is incorporated herein by reference; reactive extruded polyesters, with a gel amount of from about 10 to about 40 percent by weight, or other gel amounts, or substantially no gel, as described in U.S. Pat. No. 5,376,494, the entire disclosure of which is incorporated herein by reference; mixtures thereof and the like. Mixtures of polyester with one or more other resins can also be used. Furthermore, the polyester can be present either as a polyester homopolymer, or other resin species may be present with the polyester in the form of a copolymer, terpolymer, or the like, in block form, graft form, or the like.
Typical examples of other suitable thermoplastic toner resins include, but are not limited to, ethylene vinyl acetate (EVA) copolymers (such as the NUCREL(trademark) and ELVAX(trademark) series of resins, available from E.I. DuPont de Nemours and Company, Wilmington, Del.); copolymers of ethylene and an xcex1,xcex2-ethylenically unsaturated acid selected from the group consisting of acrylic acid and methacrylic acid; copolymers of ethylene (80 to 99.9 percent), acrylic or methacrylic acid (20 to 0.1 percent)/alkyl (C1 to C5) ester of methacrylic or acrylic acid (0.1 to 20 percent); polyethylene;
polystyrene; isotactic polypropylene (crystalline); ethylene ethyl acrylate series, such as available as BAKELITE(trademark) DPD 6169, DPDA 6182 NATURAL(trademark) (available from Union Carbide Corporation, Stamford, Conn.); ethylene vinyl acetate resins like DQDA 6832 Natural 7 (available from Union Carbide Corporation); SURLYN(trademark) ionomer resin (available from E.I. DuPont de Nemours and Company); or blends thereof; polyvinyl toluene; polyamides; styrene/butadiene copolymers; epoxy resins; acrylic resins, such as a copolymer of acrylic or methacrylic acid, and at least one alkyl ester of acrylic or methacrylic acid wherein alkyl is 1 to 20 carbon atoms, such as methyl methacrylate (50 to 90 percent)/methacrylic acid (0 to 20 percent)/ethylhexyl acrylate (10 to 50 percent); and other acrylic resins including ELVACITE(trademark) acrylic resins (available from E.I. DuPont de Nemours and Company); or blends thereof.
According to the present invention, the resin material is present in any effective amount to provide a suitable liquid toner. Generally, the resin material can be present in an amount of from about 99.9 percent to about 40 percent by weight, and preferably from about 80 percent to about 50 percent by weight, of total solids in the liquid toner composition. However, amounts outside of these ranges may be acceptable, in embodiments.
Following mixing in the first mixing step, the mixed product can, if desired, be ground to provide a material having a smaller particle size prior to being processed in the cold grinding step. Where such intermediate grinding is conducted, it is preferred that the grinding be dry grinding, i.e., in the absence of any or significant quantities of solvent and/or other liquids. Such grinding can be performed, for example, in a Fitz mill or other suitable grinding apparatus. Such grinding can be conducted to reduce the particle size of the colorant/resin composition to a smaller particle size. For example, grinding to a particle size of from about 100 to about 2,000 xcexcm, preferably 200 to about 1,500 xcexcm, or more preferably from about 500 to about 1,000 xcexcm, provides acceptable results.
Where an intermediate pre-grinding step is used and additives are to be added to the resin/colorant mixture between the first mixing step and the subsequent cold grinding step, such additives can be added at any appropriate time with respect to the pre-grinding step. That is, if desired, such additives can be added to the resin/colorant mixture after completion of the first mixing step, but prior to the pre-grinding operation. This procedure allows the additives to be mixed and ground with the resin/colorant mixture. Alternatively, the additive can be added subsequent to the pre-grinding operation but prior to the cold grinding operation. This procedure is particularly suited for situations where the additive is in either a liquid solution or dispersion form. Of course, if desired, the additive can also be fed into the resin/colorant mixture during the pre-grinding operation, if desired.
The mixed material, optionally further ground to a smaller particle size, is next generally processed in a cold grinding operation in an attritor or similar processing equipment. This cold grinding stage is generally comparable to the cold grinding operation performed in the conventional liquid toner preparation process.
The material is mixed in the mixing apparatus with a sufficient quantity of a non-polar liquid to arrive at a suitable concentration for the grinding operation, or at the desired solids content loading of the liquid toner.
Examples of suitable non-polar liquid carriers that can be used to form the liquid toners or developers according to embodiments of the present invention generally include any of the various known or after-developed liquid carriers that provide desired properties to the liquid toner. For example, suitable non-polar liquids include, but are not limited to, those having an effective viscosity of, for example, from about 0.5 to about 500 centipoise at 25xc2x0 C., and preferably from about 1 to about 20 centipoise at 25xc2x0 C., and an electrical volume resistivity equal to or greater than 1xc3x97109 xcexa9-cm, preferably greater than or equal to 5xc3x97109 xcexa9-cm, and more preferably greater than or equal to 5xc3x971013 xcexa9-cm. The liquid selected also preferably has a dielectric constant below 3.0. Moreover, the vapor pressure at 25xc2x0 C. is preferably less than 10 Torr in embodiments.
Preferably, the non-polar liquid selected for use according to the present invention is a branched chain aliphatic hydrocarbon, although straight-chain hydrocarbons can also suitably be used. A non-polar liquid of the ISOPAR(trademark) series (manufactured by the Exxon Corporation) may also be used for the liquid toners and developers of the present invention. These hydrocarbon liquids are considered narrow portions of isoparaffinic hydrocarbon fractions with extremely high levels of purity. For example, the boiling range of ISOPAR G(trademark) is between about 157xc2x0 C. and about 176xc2x0 C.; ISOPAR H(trademark) is between about 176xc2x0 C. and about 191OC; ISOPAR K(trademark) is between about 177xc2x0 C. and about 197xc2x0 C.; ISOPAR L(trademark) is between about 188xc2x0 C. and about 206xc2x0 C.; ISOPAR M(trademark) is between about 207xc2x0 C. and about 254xc2x0 C.; and ISOPAR V(trademark) is between about 254.4xc2x0 C. and about 329.4xc2x0 C. ISOPAR L(trademark) has a mid-boiling point of approximately 194xc2x0 C. ISOPAR M(trademark) has an auto ignition temperature of 338xc2x0 C. ISOPAR G(trademark) has a flash point of 40xc2x0 C. as determined by the tag closed cup method; ISOPAR H(trademark) has a flash point of 53xc2x0 C. as determined by the ASTM D-56 method; ISOPAR L(trademark) has a flash point of 61xc2x0 C. as determined by the ASTM D-56 method; and ISOPAR M(trademark) has a flash point of 80xc2x0 C. as determined by the ASTM D-56 method. In embodiments of the present invention, ISOPAR L(trademark) is the preferred liquid vehicle for the liquid toner and developer compositions.
While the ISOPAR(trademark) series liquids can be the preferred non-polar liquids for use as the dispersant in the liquid toners and developers of the present invention, the essential characteristics of viscosity and resistivity may be satisfied with other suitable liquids. Specifically, the NORPAR(trademark) series of liquids, which are substantially pure compositions of n-paraffins available from Exxon Corporation, the SOLTROL(trademark) series of liquids available from the Phillips Petroleum Company, and the SHELLSOL(trademark) series of liquids available from the Shell Oil Company can also be selected and used in embodiments of the present invention.
The amount of the liquid employed in the liquid toners and developers of the present invention is, for example, from about 85 to about 99.9 percent, and preferably from about 90 to about 99 percent by weight of the total toner or developer dispersion. However, any other effective amount of liquid may be selected, depending, for example, on the desired final use of the composition. The total solids content of the toner or developer, which include resin, colorant and other additives such as charge control additives, in embodiments is, for example, 0.1 to 15 percent by weight, preferably 0.3 to 10 percent, and more preferably, 0.5 to 10 percent by weight.
Various charge control agents are known in the art and can readily be used in the liquid toners and developers of the present invention. For example, particularly suitable charge control agents include the Pluronic series available from BASF, and particularly the PEO:PPO:PEO triblock copolymer charge control agent Pluronic F-108. Other charge control agents are disclosed, for example, in U.S. Pat. Nos. 5,866,292 and 5,688,624, the entire disclosures of which are incorporated herein by reference. In addition, aluminum di-tertiary butyl salicylate (ALOHAS) and similar compounds may also be used as the charge control agent. These latter materials can thus be used as either or both of the charge control agent and the charge director in the liquid toners and developers of the present invention.
After the ingredients are introduced into the vessel, with suitable particulate grinding media contained therein, the contents are mixed and ground for a suitable period of time to provide the desired particle size of solid material dispersed in the liquid carrier. In embodiments, the mixing is conducted, for example, for from about 0.5 to about 8 hours. Preferably, mixing is conducted for from about 1 to about 6 hours, more preferably for from about 2 to about 5 hours, and most preferably about 4 hours. Of course, longer or shorter mixing times can be used depending, for example, upon the starting particle size of the solid material, the desired final particle size of the material, and the specific nature of the composition.
The cold grinding operation is preferably conducted at a temperature of from about 0 to about 50xc2x0 C. When the grinding is to be conducted at temperatures below ambient (room) temperature, or when cooling is necessary to remove heat generated either by the mixing operation or by the mixer itself, such cooling can be achieved by any suitable means. For example, cooling can be achieved by circulating cold water or a cooling material through an external cooling jacket of the mixer, as is known to those skilled in the art.
In the mixing step, it is preferred that the particulate media be maintained in continuous or substantially continuous movement. Such movement creates shear and/or impact forces, causing a desired reduction in the particle size of the solid material. The solid material is ground so as to provide solid particles of the desired particle size. Preferably, the final average (by area) particle size of the solid material dispersed in the liquid carrier is less than 20 xcexcm, and preferably less than 10 xcexcm. More preferably, the average particle size of the solid material is from about 1 to about 10 xcexcm, more preferably from about 2 to about 8 xcexcm, and even more preferably from about 4 to about 6 xcexcm.
Following the grinding operation, the solid particles, optionally with the liquid carrier, can be removed from the mixing apparatus and separated from the grinding media. If desired, particle size classification can be used to remove solid particles from the resultant dispersion that are larger and/or smaller than a desired size range.
If necessary, the concentration of the solid particles in the dispersion can be adjusted by addition or subtraction of liquid carrier. For example, the concentration can be reduced by the addition of additional amounts of the same or different non-polar liquid. The dilution can be conducted to reduce the concentration of solid particles in the liquid toner to between about 0.1 and about 5 percent by weight, preferably from about 0.5 to about 3 percent by weight, and more preferably from about 1 to about 2 percent by weight, with respect to the non-polar liquid.
A charge director is also preferably added to the dispersion to provide the final liquid toner or developer. Charge directors are preferably included in the liquid toner in any effective amount to initiate desired charging of the solid particles contained in the dispersion. In embodiments, the charge director is included in an amount of, for example, from about 0.001 to about 5 percent by weight, and preferably from about 0.005 to about 1 percent by weight, based on a total weight of solids contained in the liquid toner.
Suitable charge directors include any of the various charge directors known in the art for initiating the desired charging of the solid particles. General classes of charge directors include the aluminum salts of alkylated salicylic acid and the aluminum salts of alkylated salicylic acid. For example, suitable charge directors for use in the liquid toners of the present invention include, but are not limited to, alumninum di-tertiary-butyl salicylate (abbreviated Alohas) and similar compounds; hydroxy bis[3,5-tertiary butyl salicylic] aluminate; hydroxy bis[3,5-tertiary butyl salicylic] aluminate mono-, di-, tri- or tetrahydrates; hydroxy bis[salicylic] aluminate; hydroxy bis[monoalkyl salicylic] aluminate; hydroxy bis[dialkyl salicylic] aluminate; hydroxy bis[trialkyl salicylic] aluminate; hydroxy bis[tetraalkyl salicylic] aluminate; hydroxy bis[hydroxy naphthoic acid] aluminate; hydroxy bis[monoalkylated hydroxy naphthoic acid] aluminate; bis[dialkylated hydroxy naphthoic acid] aluminate wherein alkyl preferably contains 1 to about 6 carbon atoms; bis[trialkylated hydroxy naphthoic acid] aluminate wherein alkyl preferably contains 1 to about 6 carbon atoms; bis[tetraalkylated hydroxy naphthoic acid] aluminate wherein alkyl preferably contains I to about 6 carbon atoms; EMPHOS PS-900(trademark); mixtures thereof and the like. Other suitable charge directors are disclosed in U.S. Pat. Nos. 5,563,015 and 5,672,456, the entire disclosures of which are incorporated herein by reference. In embodiments of the present invention, the charge director is preferably Alohas alone, or a mixture of Alohas with EMPHOS PS-900(trademark).
In other embodiments of the present invention, the charge director can be an inverse micelle, used to facilitate particle charging. The charge director can be comprised of quaternary ammonium salts, which are often polymeric in nature, conductive metal oxides, metal and organometallic salt, and the like. Suitable charge directors include, but are not limited to, those comprised of diblock or triblock copolymers of the formula A-B, BAB or A-B-A wherein the polar A block is an ammonium containing segment and B is a nonpolar block segment which, for example, provides for charge director solubility in the liquid ink fluid. Preferably, in such compounds, the A blocks have a number average molecular weight range of from about 200 to about 120,000; the B blocks have a number average molecular weight range of from about 2,000 to about 190,000; the ratio of Mw to Mn is 1 to about 5 for the copolymers; and the total number average molecular weight of the copolymer is, for example, from about 4,000 to about 300,000, and preferably about 100,000. Such materials are exemplified, for example, in U.S. Pat. No. 5,643,707, the entire disclosure of which is incorporated herein by reference.
Particularly preferred charge director compounds useful in the present invention are comprised of a protonated AB diblock copolymer selected from the group of poly(2-dimethylammonium ethyl methacrylate bromide co-2-ethylhexyl methacrylate), poly(2-dimethylammonium ethyl methacrylate tosylate co-2-ethylhexyl methacrylate), poly(2-dimethylan:monium ethyl methacrylate chloride co-2-ethylhexyl methacrylate) poly(2-dimethylammonium ethyl methacrylate bromide co-2-ethylhexyl acrylate), poly(2-dimethyla:monium ethyl acrylate bromide co-2-ethylhexyl methacrylate), poly(2-dimethylammonium ethyl acrylate bromide co-2-ethylhexyl acrylate), poly(2-dimethylammonium ethyl methacrylate tosylate co-2-ethylhexyl acrylate), poly(2-dimethylammonium ethyl acrylate tosylate co-2-ethylhexyl acrylate), poly(2-dimethylammonium ethyl methacrylate chloride co-2-ethylhexyl acrylate), and poly(2-dimethylammonium ethyl acrylate chloride co-2-ethylhexyl acrylate), poly(2-dimethylammonium ethyl methacrylate bromide co-N,N-dibutyl methacrylamide), poly(2-dimethylammonium ethyl methacrylate tosylate co-N,N-dibutyl methacrylamide), poly(2-dimethylammonium ethyl methacrylate bromide co-N,N-dibutylacrylamide), poly[2-dimethylammonium ethyl methacrylate tosylate co-N,N-dibutylacrylamide), and the like, and mixtures thereof.
As will be apparent to those of ordinary skill in the art, various other additives, known in the art, can be added to the liquid developer. Such additives can be used in their known amounts to provide known effects to the liquid developer.
As illustrated herein, the liquid inks, toners or developers of the present invention can be selected for imaging and printing methods wherein, for example, a latent image is formed on a photoconductive imaging member, such as disclosed in U.S. Pat. Nos. 4,265,990 and 5,414,498, the entire disclosures of which are incorporated herein by reference, followed by development with the liquid toner of the present invention by, for example, immersion of the imaging member in the liquid toner; transfer to a suitable substrate like paper; and fixing by heating.
Advantages of the present invention include the ability to provide low cost, high quality printing methods that include metallic colorants. The liquid toners and developers of the present invention, including the metallic colorants, provide metallic-appearing printed images that exhibit high printing quality. Furthermore, the present invention provides for metallic colored or appearing inks, which were not previously available in the field of ink jet inks, liquid toners and developers, and dry toners.

Method of producing liquid toner with metallic sheen


Compounds of the formula

Major depression is a serious health problem affecting more than 5% of the population, with a life-time prevalence of 15-20%.
Selective serotonin reuptake inhibitors have produced significant success in treating depression and related illnesses and have become among the most prescribed drugs. They nonetheless have a slow onset of action, often taking several weeks to produce their full therapeutic effect. Furthermore, they are effective in fewer than two-thirds of patients.
Serotonin selective reuptake inhibitors (SSRIs) are well known for the treatment of depression and other conditions. SSRIs work by blocking the neuronal reuptake of serotonin, thereby increasing the concentration of serotonin in the synaptic space, and thus increasing the activation of postsynaptic serotonin receptors.
However, although a single dose of an SSRI can inhibit the neuronal serotonin transporter which would be expected to increase synaptic serotonin, long-term treatment is required before clinical improvement is achieved.
It has been suggested that the SSRIs increase the serotonin levels in the vicinity of the serotonergic cell bodies and that the excess serotonin activates somatodendritic autoreceptors, 5-HT1A receptors, causing a decrease in serotonin release in major forebrain areas. This negative feedback limits the increment of synaptic serotonin that can be induced by antidepressants.
A 5-HT1A antagonist wouldt limit the negative feedback and should improve the efficacy of the serotonin reuptake mechanism. (Perez, V., et al., The Lancet, 349:1594-1597 (1997)). Such a combination therapy would be expected to speed up the effect of the serotonin reuptake inhibitor.
Thus, it is highly desirable to provide improved compounds which both inhibit serotonin reuptake and which are antagonists of the 5-HT1A receptor.
In accordance with this invention, there is provided a group of novel compounds of the formula:
wherein
R1, R3, R4, R5 and R7 are, independently, hydrogen, halo, cyano, carboxamido, carboalkoxy of two to six carbon atoms, trifluoromethyl, alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 6 carbon atoms, alkanoyloxy of 2 to 6 carbon atoms, amino, mono- or di-alkylamino in which each alkyl group has 1 to 6 carbon atoms, alkanamido of 2 to 6 carbon atoms, or alkanesulfonamido of 1 to 6 carbon atoms;
R2 and R6 are hydrogen or alkyl of 1 to 6 carbon atoms;
Z is CR7 or N;
X is O, S, H2 or F2;
the dotted lines at a and b represent independently optional double bonds; and
n is an integer 0, 1 or 2;
or a pharmaceutically acceptable salt thereof.
In some preferred embodiments of the present invention, R1 is hydrogen, hydroxy, halo, cyano, trifluoromethyl, alkyl of one to six carbon atoms or alkoxy of one to six carbon atoms. In still more preferred embodiments of the present invention, R1 is hydrogen, halo and methoxy.
In other embodiments of the invention R2 is preferably hydrogen or lower alkyl. R2 is still more preferably hydrogen.
R3, R4, and R5 are preferably independently selected from hydrogen, hydroxy, halo, cyano, carboxamido, alkyl of one to six carbon atoms, and alkoxy of one to six carbon atoms in some embodiments of the invention. Still more preferably R3, R4, and R5 are preferably independently selected from hydrogen, cyano and halogen.
R6 is preferably hydrogen or lower alkyl.
X is preferably O or H2.
Of the compounds of Formula I, still more preferred are those in which R1 is hydrogen, hydroxy, halo, cyano, trifluoromethyl, alkyl of one to six carbon atoms or alkoxy of one to six carbon atoms; R2 is hydrogen, methyl or ethyl; R3, R4, and R5 are preferably independently selected from hydrogen, hydroxy, halo, cyano, carboxamido, alkyl of one to six carbon atoms, and alkoxy of one to six carbon atoms, Z is CR7, R7 is hydrogen, hydroxy, halo, cyano, carboxamido, alkyl of one to six carbon atoms, or alkoxy of one to six carbon atoms; n is an integer 0 or 1; and R6 and the dotted lines are defined as above.
Most preferred are those examples in which R1 is hydrogen, halo or methoxy, R2 and R6 are hydrogen, R3, R4, and R5 are preferably independently selected from hydrogen, halo and cyano, Z is CR7, R7 is hydrogen, halo or cyano, n is 0 and the dotted line in the azaheterocycle represents a double bond.
This invention relates to both the R and S stereoisomers of the aminomethyl-1,4,5-trioxa-phenanthrene, as well as to mixtures of the R and S stereoisomers. Throughout this application, the name of the product of this invention, where the absolute configuration of the aminomethyl-1,4,5-trioxa-phenanthrene is not indicated, is intended to embrace the individual R and S enantiomers as well as mixtures of the two. In some preferred embodiments of the present invention the S stereoisomer is preferred.
Where a stereoisomer is preferred, it may, in some embodiments be provided substantially free of the corresponding enantiomer. Thus, an enantiomer substantially free of the corresponding enantiomer refers to a compound which is isolated or separated via separation techniques or prepared free of the corresponding enantiomer. Substantially free as used herein means that the compound is made up of a significantly greater proportion of one stereoisomer. In preferred embodiments the compound is made up of at least about 90% by weight of a preferred stereoisomer. In other embodiments of the invention, the compound is made up of at least about 99% by weight of a preferred stereoisomer. Preferred stereoisomers may be isolated from racemic mixtures by any method known to those skilled in the art, including high performance liquid chromatography (HPLC) and the formation and crystallization of chiral salts or prepared by methods described herein. See, for example, Jacques, et al., Enantiomers, Racemates and Resolutions (Wiley Interscience, New York, 1981); Wilen, S. H., et al., Tetrahedron 33:2725 (1977); Eliel, E. L. Stereochemistry of Carbon Compounds (McGraw-Hill, NY, 1962); Wilen, S. H. Tables of Resolving Agents and Optical Resolutions p. 268 (E. L. Eliel, Ed., Univ. of Notre Dame Press, Notre Dame, Ind. 1972).
Alkyl as used herein refers to an aliphatic hydrocarbon chain and includes straight and branched chains such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-pentyl, isopentyl, neo-pentyl, n-hexyl, and isohexyl. Lower alkyl refers to alkyl having 1 to 3 carbon atoms.
Alkanamido as used herein refers to the group Rxe2x80x94C(xe2x95x90O)xe2x80x94NHxe2x80x94 where R is an alkyl group of 1 to 5 carbon atoms.
Alkanoyloxy as used herein refers to the group Rxe2x80x94C(xe2x95x90O)xe2x80x94Oxe2x80x94 where R is an alkyl group of 1 to 5 carbon atoms.
Alkanesulfonamido as used herein refers to the group Rxe2x80x94S(O)2xe2x80x94NHxe2x80x94 where R is an alkyl group of 1 to 6 carbon atoms.
Alkoxy as used herein refers to the group Rxe2x80x94Oxe2x80x94 where R is an alkyl group of 1 to 6 carbon atoms.
Carboxamido as used herein refers to the group xe2x80x94COxe2x80x94NH2.
Carboalkoxy as used herein refers to the group Rxe2x80x94Oxe2x80x94C(xe2x95x90O)xe2x80x94 where R is an alkyl group of 1 to 5 carbon atoms.
Halogen (or halo) as used herein refers to chlorine, bromine, fluorine and iodine.
Pharmaceutically acceptable salts are those derived from such organic and inorganic acids as: acetic, lactic, citric, cinnamic, tartaric, succinic, fumaric, maleic, malonic, mandelic, malic, oxalic, propionic, hydrochloric, hydrobromic, phosphoric, nitric, sulfuric, glycolic, pyruvic, methanesulfonic, ethanesulfonic, toluenesulfonic, salicylic, benzoic, and similarly known acceptable acids.
Specific compounds of the present invention are:
3-[4-(5-fluoro-1-H-indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2,3-dihydro-7-H-pyrano[2,3-f][1,4]benzodioxin-7-one;
5-fluoro-3-[1,2,3,6-tetrahydro-1-[(2,3,8,9-tetrahydro-7H-pyrano[2,3-f][1,4]-benzodioxin-2-yl)methyl]-4-pyridinyl]-1H-indole;
3-[4-(1H-indol-3-yl)-3,6-dihydro-2H-pyridin-1-ylmethyl]-2,3,6,7-tetrahydro-1,4,5-trioxa-phenanthren-8-one; and
3-{1-(2,3,8,9-tetrahydro-7H-[1,4]dioxino[2,3-h]chromen-2-ylmethyl)-1,2,3,6-tetrahydropyridin-4-yl}-1H-indole; and pharmaceutical salts thereof.
Further in accordance with the present invention is provided novel intermediates of the formula:
wherein
R1 is hydrogen, halo, cyano, carboxamido, carboalkoxy of two to six carbon atoms, trifluoromethyl, alkyl of 1 to 6 carbon atoms, alkoxy of 1 to 6 carbon atoms, alkanoyloxy of 2 to 6 carbon atoms, amino, mono- or di-alkylamino in which each alkyl group has 1 to 6 carbon atoms, alkanamido of 2 to 6 carbon atoms, or alkanesulfonamido of 1 to 6 carbon atoms;
R2 is hydrogen or alkyl of 1 to 6 carbon atoms;
X is O, S, H2 or F2; and
Y is hydroxy, halogen, alkylsulfonate of 1 to 6 carbon atoms, trifluoromethanesulfonate or benzenesulfonate, in which the benzene ring is optionally substituted with halogen, nitro, trifluoromethyl, cyano, alkyl of 1 to 6 carbon atoms or alkoxy of 1 to 6 carbon atoms, and the dotted lines at a and b represent, independently, optional double bonds,
which are useful for the production of agents for the treatment of depression and other central nervous system disorders.
Specific compounds of Formula II are:
[7-Oxo-2,3-dihydro-7H-[1,4]dioxino[2,3-h]chromen-2-yl]methyl 4-methyl-benzenesulfonate;
2,3,8,9-Tetrahydro-7H[1,4]dioxino[2,3-h]chromen-2-ylmethyl 4-methyl-benzenesulfonate; and
[7-Oxo-2,3,8,9-tetrahydro-7H-[1,4]dioxino[2,3-h]chromen-2-yl]methyl 4-methylbenzenesulfonate.
The 2-azaheterocyclylmethyl-1,4,5-trioxa-phenanthrenes in which R1 is H are prepared as illustrated below. Unless otherwise noted, the variables are as defined above. Specifically, 2xe2x80x2,3xe2x80x2,4xe2x80x2-trihydroxyacetophenone (1) is regioselectively alkylated with glycidyl tosylate or halide in the presence of a suitable base such as sodium carbonate to give the benzodioxan moiety (2). Condensation with the appropriate N,N-dimethylalkanamide dimethylacetal, followed by
cyclization with sulfuric acid gives the chromone (IIa). Conversion to the tosylate (IIb) via treatment with p-toluenesulfonyl chloride in pyridine or to a halide by reaction with carbon tetrabromide or carbon tetrachloride in combination with triphenylphosphine and replacement of the tosylate or halide with the azaheterocycles appropriate to the invention yields the title compounds.
The chromone (IIb) described above is alternatively reduced to the chromane (IId) via treatment with hydrogen over platinum oxide or to the chromanone via transfer hydrogenation using ammonium formate and palladium on carbon in methanol as shown in Scheme II below. Again, the title compounds of the invention are derived by replacement of the tosylate or halide with the amines appropriate to the invention in a high boiling solvent such as DMSO.
The chromones appropriate for the invention may be alternatively prepared as shown in Scheme III below. The appropriate mono-allylated catechol (5) is elaborated with glycidyl tosylate as described above to produce (6) and rearranged in refluxing mesitylene. Cyclization to the benzodioxan methanol (7) is effected by treatment with sodium bicarbonate in ethanol and the alcohol is converted to the tosylate or halide as described above. After rearrangement of the double bond by treatment with catalytic bis-acetonitrile palladium (II) chloride in refluxing methylene chloride to produce (8) and cleavage with ozone or osmium tetroxide/sodium periodate as described above, the resulting aldehyde (9) is converted to the phenol (10) via oxidation with a suitable oxidant such as meta-chloroperoxybenzoic acid (a Baeyer-Villager reaction) followed by cleavage of the resulting formate with methanol and basic alumina. A condensation with the appropriately substituted acylacetate in the
presence of an acid such as polyphosphoric acid, sulfuric acid or phosphorus pentoxide gives the substituted chromone (IIb) appropriate for the compounds of the invention.
The acetophenones, catechols and azaheterocycles appropriate to the above chemistry are known compounds or can be prepared by one schooled in the art. The compounds of the invention may be resolved into their enantiomers by conventional methods or, preferably, the individual enantiomers may be prepared directly by substitution of (2R)-(xe2x88x92)-glycidyl 3-nitrobenzenesulfonate or tosylate (for the S benzodioxan methanamine) or (2S)-(+)-glycidyl 3-nitrobenzenesulfonate or tosylate (for the R enantiomer) in place of epihalohydrin or racemic glycidyl tosylate in the procedures above.
A protocol similar to that used by Cheetham et. al. (Neuropharmacol. 32:737, 1993) was used to determine the affinity of the compounds of the invention for the serotonin transporter. The compound""s ability to displace 3H-paroxetine from male rat frontal cortical membranes was determined using a Tom Tech filtration device to separate bound from free 3H-paroxetine and a Wallac 1205 Beta Plate(copyright) counter to quantitate bound radioactivity. Ki""s thus determined for standard clinical antidepressants are 1.96 nM for fluoxetine, 14.2 nM for imipramine and 67.6 nM for zimelidine. A strong correlation has been found between 3H-paroxetine binding in rat frontal cortex and 3H-serotonin uptake inhibition.
High affinity for the serotonin 5-HT1A receptor was established by testing the claimed compound""s ability to displace [3H] 8-OHDPAT (dipropylaminotetralin) from the 5-HT1A serotonin receptor following a modification of the procedure of Hall et al., J. Neurochem. 44, 1685 (1985) which utilizes CHO cells stably transfected with human 5-HT1A receptors. The 5-HT1A affinities for the compounds of the invention are reported below as Ki""s.
Antagonist activity at 5-HT1A receptors was established by using a 35S-GTPxcex3S binding assay similar to that used by Lazareno and Birdsall (Br. J. Pharmacol. 109: 1120, 1993), in which the test compound""s ability to affect the binding of 35S-GTPxcex3S to membranes containing cloned human 5-HT1A receptors was determined. Agonists produce an increase in binding whereas antagonists produce no increase but rather reverse the effects of the standard agonist 8-OHDPAT. The test compound""s maximum inhibitory effect is represented as the Imax, while its potency is defined by the IC50.
The results of the three standard experimental test procedures described in the preceding three paragraphs were as follows:
Like the antidepressants fluoxetine, paroxetine and sertraline, the compounds of this invention have the ability to potently block the reuptake of the brain neurotransmitter serotonin. They are thus useful for the treatment of diseases commonly treated by the administration of serotonin selective reuptake inhibitor (SSRI) antidepressants, such as depression (including but not limited to major depressive disorder, childhood depression and dysthymia), anxiety, panic disorder, post-traumatic stress disorder, premenstrual dysphoric disorder (also known as pre-menstrual syndrome), attention deficit disorder (with and without hyperactivity), obsessive compulsive disorder (including trichotillomania), social anxiety disorder, generalized anxiety disorder, obesity, eating disorders such as anorexia nervosa, bulimia nervosa, vasomotor flushing, cocaine and alcohol addiction, sexual dysfunction (including premature ejaculation), and related illnesses. Moreover, the compounds of this invention have potent affinity for and antagonist activity at brain 5-HT1A serotonin receptors. Recent clinical trials employing drug mixtures (eg, fluoxetine and pindolol) have demonstrated a more rapid onset of antidepressant efficacy for a treatment combining SSRI activity and 5-HT1A antagonism (Blier and Bergeron, 1995; F. Artigas et. al., 1996; M. B. Tome et. al., 1997). The compounds of the invention are exceedingly interesting and useful for treating depressive illnesses.
Thus the present invention provides methods of treating, preventing, inhibiting or alleviating each of the maladies listed above in a mammal, preferably in a human, the methods comprising providing a pharmaceutically effective amount of a compound of this invention to the mammal in need thereof.
Also encompassed by the present invention are pharmaceutical compositions for treating or controlling disease states or conditions of the central nervous system comprising at least one compound of Formula I, mixtures thereof, and or pharmaceutical salts thereof, and a pharmaceutically acceptable carrier therefore. Such compositions are prepared in accordance with acceptable pharmaceutical procedures, such as described in Remingtons Pharmaceutical Sciences, 17th edition, ed. Alfonoso R. Gennaro, Mack Publishing Company, Easton, Pa. (1985). Pharmaceutically acceptable carriers are those that are compatible with the other ingredients in the formulation and biologically acceptable.
The compounds of this invention may be administered orally or parenterally, neat or in combination with conventional pharmaceutical carriers. Applicable solid carriers can include one or more substances which may also act as flavoring agents, lubricants, solubilizers, suspending agents, fillers, glidants, compression aids, binders or tablet-disintegrating agents or an encapsulating material. In powders, the carrier is a finely divided solid which is in admixture with the finely divided active ingredient. In tablets, the active ingredient is mixed with a carrier having the necessary compression properties in suitable proportions and compacted in the shape and size desired. The powders and tablets preferably contain up to 99% of the active ingredient. Suitable solid carriers include, for example, calcium phosphate, magnesium stearate, talc, sugars, lactose, dextrin, starch, gelatin, cellulose, methyl cellulose, sodium carboxymethyl cellulose, polyvinylpyrrolidine, low melting waxes and ion exchange resins.
Liquid carriers may be used in preparing solutions, suspensions, emulsions, syrups and elixirs. The active ingredient of this invention can be dissolved or suspended in a pharmaceutically acceptable liquid carrier such as water, an organic solvent, a mixture of both or pharmaceutically acceptable oils or fat. The liquid carrier can contain other suitable pharmaceutical additives such as solubilizers, emulsifiers, buffers, preservatives, sweeteners, flavoring agents, suspending agents, thickening agents, colors, viscosity regulators, stabilizers or osmo-regulators. Suitable examples of liquid carriers for oral and parenteral administration include water (particularly containing additives as above e.g. cellulose derivatives, preferably sodium carboxymethyl cellulose solution), alcohols (including monohydric alcohols and polyhydric alcohols e.g. glycols) and their derivatives, and oils (e.g. fractionated coconut oil and arachis oil). For parenteral administration the carrier can also be an oily ester such as ethyl oleate and isopropyl myristate. Sterile liquid carriers are used in sterile liquid form compositions for parenteral administration.
Liquid pharmaceutical compositions which are sterile solutions or suspensions can be utilized by, for example, intramuscular, intraperitoneal or subcutaneous injection. Sterile solutions can also be administered intravenously. Oral administration may be either liquid or solid composition form.
Preferably the pharmaceutical composition is in unit dosage form, e.g. as tablets, capsules, powders, solutions, suspensions, emulsions, granules, or suppositories. In such form, the composition is sub-divided in unit dose containing appropriate quantities of the active ingredient; the unit dosage forms can be packaged compositions, for example packeted powders, vials, ampoules, prefilled syringes or sachets containing liquids. The unit dosage form can be, for example, a capsule or tablet itself, or it can be the appropriate number of any such compositions in package form.
The amount provided to a patient will vary depending upon what is being administered, the purpose of the administration, such as prophylaxis or therapy, and the state of the patient, the manner of administration, and the like. In therapeutic applications, compounds of the present invention are provided to a patient already suffering from a disease in an amount sufficient to cure or at least partially ameliorate the symptoms of the disease and its complications. An amount adequate to accomplish this is defined as a xe2x80x9ctherapeutically effective amount.xe2x80x9d The dosage to be used in the treatment of a specific case must be subjectively determined by the attending physician. The variables involved include the specific condition and the size, age and response pattern of the patient. Generally, a starting dose is about 5 mg per day with gradual increase in the daily dose to about 150 mg per day, to provide the desired dosage level in the human.
Provide as used herein means either directly administering a compound or composition of the present invention, or administering a prodrug, derivative or analog which will form an equivalent amount of the active compound or substance within the body.
The present invention includes prodrugs of compounds of Formula I. xe2x80x9cProdrugxe2x80x9d, as used herein means a compound which is convertible in vivo by metabolic means (e.g. by hydrolysis) to a compound of Formula I. Various forms of prodrugs are known in the art, for example, as discussed in Bundgaard, (ed.), Design of Prodrugs, Elsevier (1985); Widder, et al. (ed.), Methods in Enzymology, vol. 4, Academic Press (1985); Krogsgaard-Larsen, et al., (ed). xe2x80x9cDesign and Application of Prodrugs, Textbook of Drug Design and Development, Chapter 5, 113-191 (1991), Bundgaard, et al., Journal of Drug Deliver Reviews, 8:1-38(1992), Bundgaard, J. of Pharmaceutical Sciences, 77:285 et seq. (1988); and Higuchi and Stella (eds.) Prodrugs as Novel Drug Delivery Systems, American Chemical Society (1975).
The following examples illustrate the production of representative compounds of this invention.
To a solution of 2xe2x80x2,3xe2x80x2,4xe2x80x2-trihydroxyacetophenone (10.6 g, 63.0 mmole) in DMF (75 mL) was added potassium carbonate (17.4 g, 126 mmole). After 5 minutes (R)-glycidyl tosylate (9.67 g, 42,3 mmole) was added then the heterogeneous mixture was heated to 70xc2x0 C. for 3 hours. After removal of the solvent in vacuum, the residue was taken into water (800 mL) and was then extracted with ethyl acetate (4xc3x97300 mL). The combined organic layers were dried over MgSO4, filtered and evaporate to dryness in vacuum. The crude brown oil thus obtained was column chromatographed on silica gel with 40% hexane/ethyl acetate as eluant to give the (S)-enantiomer of the title compound as a yellow oil which solidifies upon standing (7.5 g, 78%). MS (ESI) m/z 223 (Mxe2x88x92H)xe2x88x92.
Elemental Analysis for: C11H12O5.0.10 H2O
Calc""d: C, 58.46; H, 5.44
Found: C, 58.02; H, 5.09
To a solution of 1-[(3S)-5-hydroxy-3-(hydroxymethyl)-2,3-dihydro-1,4-benzodioxin-6-yl]-1-ethanone (0.75 g, 3.35 mmole) in xylenes (50 mL) was added N,N-dimethylformamide dimethyl acetal (0.65 mL, 4.89 mmole). The solution was heated to 120xc2x0 C. for 45 minutes under nitrogen. Upon cooling to room temperature, a yellow solid xcex2-amino enone intermediate precipitated from solution and was filtered. Cyclization of this intermediate was effected by treatment with a mixture of 5 mL of concentrated sulfuric acid and 25 mL of water for 1 hour at room temperature. The mixture was then diluted to 200 mL with water and extracted with 200 mL of ethyl acetate. The extract was dried over magnesium sulfate. After filtration and evaporation in vacuum, the crude product was column chromatographed on silica gel with 2% methanol/methylene chloride to give 0.66 g (85%) of the product, the (S)-enantiomer of the title compound, as a white solid, m.p. 125xc2x0 C. MS (+APCI) m/z 235 (M+H)+.
Elemental Analysis for: C12H10O5.0.25 H2O
Calc""d: C, 60.38; H, 4.43
Found: C, 60.13; H, 4.83
p-Toluenesulfonyl chloride (0.60 g, 3.15 mmole) was added to solution of (2S)-2-(hydroxymethyl)-2,3-dihydro-7H-[1,4]dioxino[2,3-h]chromen-7-one (0.41 g, 1.75 mmole) in 50 mL of pyridine. The solution was stirred at room temperature overnight under nitrogen. Water was added to quench the excess tosyl chloride and the solvent was removed in vacuum and replaced with methylene chloride. The solution was washed with 2N aqueous HCl, with saturated aqueous sodium bicarbonate, and with saturated brine, and dried over magnesium sulfate. Filtration, evaporation in vacuum and column chromatography on silica gel with 3% methanol/methylene chloride as eluant gave 0.36 g (54%) of the (R)-enantiomer of the title compound as a yellow solid, m.p. 190-191xc2x0 C.
Elemental Analysis for: C19H16O7S.0.20 H2O
Calc""d: C, 58.22; H, 4.22
Found: C, 57.88; H, 3.93

Antidepressant azaheterocyclylmethyl derivatives of 1,4,5-trioxa-phenanthrene

Abstract: Compounds of the formula

Abstract: useful for the treatment of diseases such as depression (including but not limited to major depressive disorder, childhood depression and dysthymia), anxiety, panic disorder, post-traumatic stress disorder, premenstrual dysphoric disorder attention deficit disorder (with and without hyperactivity), obsessive compulsive disorder (including trichotillomania), social anxiety disorder, generalized anxiety disorder, obesity, eating disorders such as anorexia nervosa, bulimia nervosa, vasomotor flushing, cocaine and alcohol addiction, sexual dysfunction and related illnesses.


A blue glass composition comprises conventional soda-lime-silica glass ingredients and specific amounts of Fe.sub.2 O.sub.3, Co.sub.3 O.sub.4, NiO, and optionally Se, resulting in an Illuminant C transmittance of 54%.+-.3% at one quarter inch thickness, a dominant wavelength of 482 nm.+-.1 nm, and a color purity of 13%.+-.1%.

Glass compositions having various colors are used, for example, by architects in glazing buildings. Normally, the color selected by the architect serves several functions. A first function of the color is to make the glass aesthetically pleasing when viewed from the exterior of the building. Aesthetics will determine the acceptability of a desired particular glass color and, in part, the desired intensity of the color. A second function is to reduce the amount of heat absorbed from the exterior of the building to the interior of the building, so that the air conditioning load in the building is reduced. Generally, more color added to glass results in greater heat absorption. In addition, while color may readily be added to glass to serve these functions, that glass when colored still must have an appropriate visible light transmittance value.
Those skilled in the art of formulating glass compositions are familiar with various suitable glass colorants. Thus, a small amount of cobalt oxide is known to produce a cold blue color widely considered unattractive and undesirable for architectural and certain other uses. A high concentration of nickel is known to produce black glass. Selenium can produce pink or red, and ferrous oxide can produce green glass and contribute to advantageous solar load control properties. The glass color produced by a mixture of colorants will vary with both the amount and relative proportions used. As noted above, varying the choice and amount of colorants also affects the light transmittance value of the glass. As discussed further below, however, the effect on glass color and transmittance of mixing multiple colorants and/or varying the amount of relative proportions of the colorants is not reliably predictable.
In the following discussion, certain terms well known to those skilled of the art are used to describe color in glass. One method of specifying color is by the use of dominant wavelength and color purity. These are derived from tristimulus coefficients that have been defined by the CIE (Commission Internationale de l'Eclairage). Numerical values for a given glass color can be determined by calculating the trichromatic values X, Y, and Z. From the tristimulus values for that glass color, trichromatic coefficients x, y and z are then calculated and plotted on a chromaticity diagram. The 1931 Standard Observer response diagram defines the amount of each of three primary colors (x is amber, y is green, and z is blue) required to produce energy of each wavelength from 3,800 Angstroms to 7,500 Angstroms, wherein the green curve is the standard luminosity curve for the human eye. The dominant wavelength and color purity is then numerically determined with respect to the coordinates of Illuminant C, an established light source.
Thus, a glass color may be specified either by its trichromatic coefficients x and y or by its dominant wavelength and purity values. The lower the color purity, the closer the color is to the Illuminant C standard and the closer it is to being a neutral color.
An understanding of the foregoing terms and definitions thereof may be had by reforming to the Handbook of Colorimetry prepared by the staff of the Color Measurement Laboratory, Massachusetts Institute of Technology. This book was printed in 1936 by the Technology Press, Massachusetts Institute of Technology, Cambridge, Mass. Also, a good explanation and list of definitions is given in Color in Business, Science and Industry, (3 Ed.) John Wiley & Sons (especially pages 170-172, 377-378). Useful also is An Introduction to Color, John Wiley & Sons (especially pages 105-106).
Those skilled in the art know that adding or substituting one colorant for another and/or changing the amount or relative proportion of colorants in a glass composition affects not only the color of the glass, i.e., its dominant wavelength and its color purity, but also affects the light transmittance of the glass and its structural qualities. Furthermore, there is in many cases substantial complexity and unpredictability in these effects. Thus, for example, even if the proper alteration in the composition of a particular color glass were determined for achieving a desired color shift, the same alteration, unfortunately, would also alter (for example, unacceptably reduce) the light transmittance of the glass. It may, of course, also undesirably alter the color purity of the glass. In short, all these factors--dominant wavelength, purity, and light transmittance--are variable, and may vary unpredictably with each other. Developing a new glass composition, therefore, having a particular color and appropriate light transmittance value, is in some cases like searching for a needle in a haystack. An experimental change in the amount or relative proportion of one or more colorants in a glass composition intended to bring one of these numerical values closer to a target value causes one or both of the other values simultaneously to drift off target (or further off target).
The difficulty of this task, finding the correct glass composition for a colored glass having the desired dominant wavelength, color purity, and light transmittance, is discussed in U.S. Pat. No. 3,296,004 to Duncan, wherein a neutral brown heat absorbing glass is disclosed. Duncan expressly noted that the development of the particular color requires a careful consideration of the transmittance characteristics of the glass and that the amounts of the colorants must be carefully controlled to achieve the desired color (dominant wavelength and color purity), transmittance, and heat-absorbing characteristic. Thus, for example, Duncan pointed out that if his glass contained more cobalt oxide than be specified, the color would be more blue than desired. Considering the glass composition of the present invention for a moment, however, the great unpredictability of this area is well demonstrated by the fact that it employs cobalt oxide in an amount well within the range used by Duncan, yet achieves a blue, not a brown color. That is, the amount of cobalt oxide used by Duncan to produce brown surprisingly yields the attractive blue color in combination with the other components of the glass composition of the present invention, notwithstanding the fact that such other components are not normally associated with producing blue coloration.
This inherent unpredictability in achieving specific purity, dominant wavelength, and light transmittance values simultaneously in a glass composition had to be overcome in discovering the glass composition of the present invention. A series of blue glass compositions was fabricated for aesthetic evaluation for automotive and architectural uses, and the like. From amongst the many samples, one was chosen having a very attractive blue color--the color of the glass composition of the present invention. In particular, it was a blue having a dominant wavelength of 482 nm.+-.1 nm and a purity of 13%.+-.1%. These values correspond to the color coordinates of the glass, i.e., trichromatic coefficients, of about x=0.2799 and y=0.2947.
The task then was to develop a blue glass composition including appropriate colorants which yielded the same dominant wavelength and color purity, but with a desired Illuminant C transmittance value of 54%.+-.3%. As explained above, however, altering the various colorants, the amounts, and relative proportions in which they were used, for purposes of achieving the correct light transmittance value simultaneously caused the color, that is the dominant wavelength and purity, to drift off target.
The visible light transmittance value of the blue glass of the present invention is dictated by an important commercial consideration. Specifically, glass of the same composition has to be suitable for both motor vehicle glazing and architectural glazing applications. That is, in order to achieve significant manufacturing cost savings, glass for both architectural glazing and automotive glazing applications had to be producible together on the same float glass production line. To use the same glass in both of these applications, it must have an Illuminant A transmittance at least high enough to meet applicable government standards for motor vehicle glazings, and yet low enough to provide heat load reduction to meet architectural glazing specifications. Thus, an Illuminant C transmittance value of 54%.+-.3% was determined for the glass, at one quarter inch thickness. This meets various applicable architectural standards and, when used as one of the 0.090 inch thick glass panels (the other 0.090 inch thick glass panel being clear) in a laminated safety glass windshield, yields the desired blue of the invention with an Illuminant A visible light transmittance of at least 70% to meet current U.S. government standards for motor vehicle windshields.
Dozens of experimental glass compositions were tried without success. The numerous variables affecting color in a glass composition, e.g., selection of colorant(s), their amounts, relative amounts, etc., and the unpredictability of the type or degree of change effected by varying one or more of them led to failure after failure. The search continued and dozens of additional experimental glass compositions were tried. Those skilled in the practical aspects of this art will understand the very considerable effort and expense involved in a research and development program of this nature. Still the glass compositions which provided the necessary light transmittance together with the selected dominant wavelength and the selected purity were undiscovered. More time, money, and effort were expended to produce and test dozens of additional experimental glass compositions. All of these were also unsuccessful.
Finally a glass composition was produced and tested and found to have the needed Illuminant C transmittance of 54%.+-.3% in conjunction with the desired blue color having a dominant wavelength equal to 482 nm.+-.1 nm and a color purity equal to 13%.+-.1%. Furthermore, as disclosed below, this was achieved using four colorants, each readily commercially available at resonable cost and each used in a practical, easily measured quantity.
A blue glass having approximately the same transmittance, dominant wavelength, and excitation purity values, but containing only three colorants, is disclosed in U.S. Pat. No. 4,866,010 to Boulos et al. However, the patent does not suggest that a fourth colorant may be added, and the proportions of the original three colorants modified, to achieve virtually the same values for transmittance, dominant wavelength, and color purity as for the present inventive glass composition. Specifically, the patent does not suggest, and in fact teaches away from, the use of nickel, which typically imparts a reddish-brown color to glass, as a component of the present inventive blue glass composition.
U.S. Pat. No. 2,938,808, subsequently reissued as U.S. Pat. No. Re. 25,312, discloses as a new article of manufacture a neutral color sheet of glass having a thickness in the range of 1/8-1/4 inch. The glass is suitable for glazing purposes and has a substantially uniform transmittance for light in the portion of the spectrum between 440 and 660 millimicrons, a color purity below 7%, a total solar energy transmittance between 40% and 48%, and a total luminous transmittance between 35% and 45%, at a thickness of 1/4 inch. The disclosed glass composition consists essentially of base ingredients in percentages by weight as follows: 60-75% SiO.sub.2, 11-20% Na.sub.2 O, 0-10% K.sub.2 O, the sum of the Na.sub.2 O and the K.sub.2 O being 11-21%, 6-16% CaO, and 0-10% MgO, the sum of the CaO and MgO being 6-18%, together with 0.4% Fe.sub.2 O.sub.3, 0.0076-0.008% Co.sub.3 O.sub.4, 0.009-0.126% NiO, and 0.005-0.0056% Se. The patent teaches that the amounts of the colorants Fe.sub.2 O.sub.3, Co.sub.3 O.sub.4 , NiO, and Se are greater when the thickness of the sheet is less than 1/4 inch, and is approximately twice the above listed amounts for each colorant when the thickness of the sheet is 1/8 inch.
U.S. Pat. No. 3,723,142 discloses a neutral gray colored heat absorbing glass having a low color purity. The glass is defined as consisting essentially of the following base components in percentages by weight: 68-75% SiO.sub.2, 0-5% Al.sub.2 O.sub.3, 5-15% CaO, 0-10% MgO, the sum of the CaO and the MgO being 6-15%, 10-18% Na.sub.2 O, and 0-5% K.sub.2 O, the sum of the Na.sub.2 O and the K.sub.2 O being 10-20%, together with coloring components of 0.1-0.5% Fe.sub.2 O.sub.3, 0.003-0.02% Co.sub.3 O.sub.4, 0.0005-0.001% Se, and negligible NiO. The patent states that the quantity of NiO should be less than about 0.002% and preferably less than 0.0004%.
U.S. Pat. No. 3,498,806 discloses various specific compositions for glasses of "generally blue" coloration, along with compositions for clear glass and glasses of green or other coloring. None of these compositions, however, is the same or even similar to the composition of the glass of the present invention. They differ most notably in both the selection of colorants (using certain colorants not used in the present invention and others which are used) and the amounts and relative proportions of the colorants. Specifically, the patent does not disclose the use of nickel in the glass composition.
Finally, U.S. Pat. No. 4,101,705 discloses neutral bronze glazings having a dominant wavelength in the range of 570 nm to 580 nm and a color purity from 2% to 6%. the weight percentages of Co.sub.3 O.sub.4 and NiO are lower, and the weight percentage of Se is higher, than the allowable ranges for these colorants in the present invention.
It must be noted that the prior art referred to hereinabove has been collected and examined only in light of the present invention as a guide. It is not to be inferred that such diverse art would otherwise be assembled absent the motivation provided by the present invention, nor that the cited prior art when considered in combination suggests the present invention absent the teachings herein.


In order to avoid local overheating on the surface of an intrinsically safe measuring transducer provided with current limiting resistors and embedded in a sealing composition, a body of a good heat conducting material is arranged within the sealing composition in the vicinity of the current limiting resistors.

The invention is directed to a device for avoiding local overheating of intrinsically safe measuring transducers embedded in a sealing composition and provided with current limiting resistors with the assistance of bodies made of a good heat conducting material.
It is customary in chemical process engineering to raise the signals sensitive to disturbances of primary elements such as, e.g., thermoelements and resistance thermometers, to a signal level which only has a slight sensitivity to disturbance through the use of measuring transducers, also called transmitters, so that these signals can be carried over great distances. Thus, it is customary, for example, to use as the carrying signal a current impressed by the measuring transducer depending on the size of the measuring signal.
It is suitable for reducing the disturbance to hold the cable between the measuring element and the measuring transducer as short as possible. Therefore, customarily such measuring transducers are mounted in the direct vicinity of the measuring assembly of, e.g., thermoelements. It is ideal to install the measuring transducer in the connection head of the assembly itself.
There is frequently the danger of explosions in chemical plants, especially in organic chemistry plants. Electrical machining employed in these areas, therefore, are not allowed to contain any undesired ignition sources. In regard to this, there are a set of corresponding legal codes (e.g., Factory Mutual Approval Standards).
Various types of protection are permitted to protect electrical machinery from explosion. For measuring apparatus, such as, e.g., measuring transducers, there has especially come into use the type of protection called "intrinsically safe". With this type of protection, care must be taken that the voltages and currents occurring in machinery in a space endangered by the possibility of explosion are held so small that their energy is not sufficient for ignition of explosive gas mixtures. In other words, care must be taken so that there is no local overheating in the measuring transducer in the area subject to the danger of explosion which would release an explosion if it came into contact with an ignitable mixture. Therefore, it is customary to tightly seal such measuring transducers with special sealing compositions.
Local overheating also must be safely avoided if a disturbance occurs and if a partial or complete short circuit is present in the measuring transducer. Therefore, it is customary in this case to also embed in the sealing composition especially reliable prominent current limiting resistors. However, in the case of a disturbance, wattages are transformed in these resistors which lead to excess temperatures at the resistor which themselves are sufficient for ignition. It is true that through the sealing composition the ignitable mixture is kept away from the hot resistor, but care must be taken that the outer temperature of the sealing composition at no place reaches the ignition point. Futhermore, the sealing coposition cannot be allowed to be damaged at any place by the high excess temperature of the current limiting resistors so that no cracks are formed so that the ignitable mixture reaches the hot resistor. This creates difficulties in small structures in which it is easy to have localization of heat, such as in, e.g., transmitters which should be mounted in the connection head of assemblies.
There is known from German OS No. 2937218 a device for avoiding local overheating on transmitters in sealing compositions, which transmitters are provided with current limiting resistors whereby the surfaces of the sealing compositions are provided with one or more good heat conducting boundary surfaces for the dissipation of heat. There are specially used for this purpose sheets and panels made of copper or aluminum. However, this apparatus has the disadvantage that there must be contact protection for the metal surfaces which can occur through ground. Therefore, in many cases, there must be provided additional measures for grounding which can lead to problems in high frequency sweep radiation since the potential of the inner circuitry of the measuring transducer customarily must be independent of the ground potential.
Therefore, it was the purpose of the present invention to develop an apparatus for avoiding local overheating of "intrinsically safe" measuring transducers embedded in sealing compositions and provided with current limiting resistors with the assistance of bodies made of a good heat conducting material such that additional grounding is unnecessary.

Device for avoiding local overheating on measuring transducers