MXPA95005082A - Medium of low viscosity and high load, for a ceramic composition of recubrimie - Google Patents

Abstract

The present invention relates to a medium to be used in the preparation of a ceramic coating composition, the medium comprises a solvent base of tripropylene glycol methyl ether in an amount of about 50% to 99% by weight, the improvement wherein the medium contains approximately 0.1 to 50% by weight of pantoten

Description

HALF LOW VISCOSITY AND HIGH LOAD. FOR ONE CERAMIC COATING COMPOSITION OWNER: CERDECAKTIENGESELLSCHAFTKERAMISCHE FARBEN society of German nationality, domiciled at: Gutleutstrasse 215, D-60327 Frankfurt - Germany INVENTOR: TERRY JOSEPH BROWN, residing at: 60 Mainsgate Street, Pittsburgh, Pennsylvania 15205 - USA Profession: Associated chemist, American citizen.- The present invention provides an improved medium (or vehicle) for ceramic coating compositions. BACKGROUND OF THE INVENTION Ceramic coating compositions are well known which are particularly useful for achieving decorative and functional coatings for glasses, porcelain ware, and the like. Generally, said compositions take the form of pastes to be applied with squeezing rollers or coating paints to be applied with rollers, and they must have specific properties in order to constitute a workable product. The viscosity of the medium or vehicle used to prepare the composition is especially important. Also important is the capacity of loading or inclusion of solids (ratio: powder / oil), of the pasty materials made with the medium. Additionally, the rheology, or profile of the viscosities, of the paste applicable by means of a wringer roll or of the coating paste applicable by roller, is an important factor. In general terms, the ceramic coating compositions are composed of a glass frit, a vehicle or medium, and optionally, a pigment. Typically, the composition in the form of a paste is applied to a substrate such as a automotive glass, by silk screen or screen printing, or by another application technique, and the coated substrate is heated or subjected to cooking for the purpose of melting the glass frit and volatilizing the vehicle or medium, whereby the coating adheres firmly to the surface of the substrate. The vehicles or media that have been previously used in the coating ceramic compositions are typically organic and include compositions based on pine oils, vegetable oils, mineral oils, low molecular weight petroleum fractions, tridecyl alcohol, and the like. The vehicles can be modified by the addition of viscous resins such as vinyl resins, solvents, film formers such as cellulosic materials, and the like. In the art there is a need for coating ceramic compositions in the form of paste, provided with a high solids content. This results in products that have a lower volatile organic content (VOC). The need for products with a lower volatile organic content is particularly important in ceramic coating products in which lead-free frits are used, since these products have a lower density. DESCRIPTION OF THE INVENTION The invention provides an improved means or vehicle, intended to be used in the formation of ceramic coating compositions. The improvement of the present invention comprises the use of pantothenol (pantotenyl alcohol) as a rheological modifier in the medium or vehicle.

Pantothenol, or pantotenyl alcohol, is the compound called 2,4-Dihydroxy-N- (3-hydroxypropyl) -3,3-dimethylbutanamide. The compound exists as a racemic mixture (+ -). The (+) and (-) enantiomers are also known, and the D (+) form is also known to have a vitamin activity.

The racemic mixture, or the individual enantiomers, can be used in the present invention; however, for economic reasons the racemic mixture is preferred. In general, the medium of the invention comprises a solvent base in an amount of about 50 to 99% by weight, from 0 to about 45% by weight, of a binder, from about 0.1 to 50%, by weight, of pantothenol, from 0 to about 15%, of plasticizer, and from 0 to about 15% by weight, of a viscosity modifier. The solvent base for the medium may be a material, or a mixture of materials, of those previously used in the field of ceramic coating compositions. As examples of such materials, we have pine oil, terpineol, ester alcohols, alcohols such as tridecyl alcohol, glycols, glycol ethers, aromatic hydrocarbons, isoparaffin hydrocarbons and aliphatic hydrocarbons. The methyl ester of tripropylene glycol is particularly suitable. The medium optionally includes a binder in an amount of up to about 45% by weight. Such binders are known in the art. By way of examples of such binders, mention may be made of polystyrenes and modified polystyrenes, for example, piccolatic resin; poly-alpha-methylstyrene, for example, Kristalex resin; partially hydrogenated resins, for example, stabelite resin; resin rosin hydrogenated esters, for example, stabelite esters; resins such as the homo- and co-polymers of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate and isobutyl methacrylate. Optionally, the medium includes up to about 15% by weight of a plasticizer. Such plasticizers are known in the art, and by way of examples thereof, mention may be made of: dibutyl phthalate, dioctyl phthalate, tributyl phosphate, stearate compounds, rosin methyl esters, for example, Abayl, hydroabietic alcohol, for example, Abitol, the hydrogenated methyl ester of rosin, for example, Hercolyn-D and Amine-D. As an optional component, the medium can contain up to about 15% by weight, of a viscosity modifier.

Such modifiers are also known in the art, and by way of examples may be mentioned ethyl cellulose, nitro cellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose, acrylic resins, poly (vinyl) butyral resins, carboxymethyl cellulose, and ethylhydroxy -ethyl cellulose. The medium may also contain other modifying components such as a dispersant and an odor masker, if desired. Said materials are known in the art, and it is possible to use any of the known materials, as long as they are compatible with the other components of the medium. The medium can be prepared by combining the necessary components, and, if necessary, heating them, in order to put all the components in a state of solution. For illustrative purposes: the pantotenyl alcohol and, optionally, the binder, plasticizer and viscosity modifier are added to the solvent base.

The mixture is heated to approximately 150 ° to 200 ° F (65.6 to 93.3 ° C) until a uniform solution is formed. The solution is then cooled and additional optional components such as dispersant and odor masker are added under mixing to obtain a uniform solution. The medium or vehicle thus formed can be used as an organic medium or vehicle to prepare a ceramic coating composition.

By using the medium of the invention, a coating composition having a much higher solids loading, a higher density of the printed film by screen printing or roller applied film, and a lower VOC can be produced as a result direct from the highest load of solids. Also, the resulting ceramic coating composition has a better stability of viscosity, over time. The higher density of the printed film results in a lower light transmission, and in a better opacity of the films subjected to firing. The medium of the invention has a very low viscosity, and allows the production of a ceramic coating composition whose viscosity has excellent stability and which will not segregate or settle during storage. The medium of the invention can be used in the formation of coating ceramic compositions of the type disclosed in for example, U.S. Patent Nos. 4,959,090, 4,970,178 and 4,892,847.

Said Patents are, of course, purely illustrative and not exhaustive, of the compositions in which the medium of the invention can be used.

The medium can also be used in the formation of metallizing ceramic compositions which are suitable for the production of electrically conductive films subjected to firing. See, for example, US Patents No. 4,98,949, No. 4,369,063, No. 4,029,605 and No. 5,346,651. The medium of the invention is particularly useful in the preparation of ceramic coating compositions in which the glass frit used is a lead-free glass frit. Said compositions, and lead-free glass frits, are well known. Generally speaking, the ceramic coating compositions comprise the glass frit, the medium or vehicle, and optionally, a pigment. In the case of the metallizing compositions, a finely divided electrically conductive metal, such as silver, is also present. Other components may be used in order to adjust the properties of the composition, as is known in the art. The improvement of the present invention resides in the use of the medium of the present invention, as a medium or vehicle in said compositions. It should also be noted that the medium of the invention can be independently provided as a separate product that can be used as a diluent for the ceramic coating compositions. Therefore, the properties for coating or printing, of said coating compositions, can be adjusted at the time of use, by adding the desired amount of the medium, to said composition. For purposes of illustrating the present invention, the following examples are presented. It should be emphasized that said examples are purely illustrative and not exhaustive of the invention. Example 1 35.192 parts by weight of tripro-phenylene glycol methyl ether (Arcosolve TPM) were added to a container, and heating was started. DL Pantothenol Cosmetic Quality (2.736 parts by weight) and hydroxypropylcellulose (1.048 parts by weight of Klucel E) were added to the container, continuing mixing and heating until the temperature of the mixture reached 175 ° F (79.4 ° C). C). Heating was interrupted when pantothenol and Klucel E dissolved. The mixture was allowed to cool for 40 minutes. At this time, 0.604 parts by weight of dispersant (Disperbyk 110, a saturated polyester, with acid groups) and 0.06 parts by weight of an odor masker (Fresh Linen 6503/2), were added under agitation. The resulting mixture was filtered through a 325 mesh screen to obtain the medium of the invention. The Klucel E, is a trademark of the Aqualon Company. The Arcosolve TPM is a trademark of ARCO Chemical Co.

The Disperbyk 110 is a trademark of BYK Chemie, Additives Division. Fresh LInen 6503/2 is a trademark of Givaudan-Roure. EXAMPLE 2 A black coating ceramic composition was prepared using the medium of Example 1. A black enamel powder containing glass frit and pigments was combined with the medium of Example 1 and mixed until homogeneous. After mixing, the resulting paste was milled using a three-roll mill. The resulting paste had a solids content, 82 to 84% by weight, and the content of the medium, is from 16 to 18% by weight. Composition of black enamel powder: 75.75% by weight, of glass frit (1); 15.15% by weight, of black pigment No. 1 (2); 9.11% by weight, of black pigment No. 2 (3) (1) Composition of the frit: PbO 61.09% by weight; Si02 29.23% by weight; Na2?: B2? 3 5.62% by weight; Zr02: SiO2 1.92% by weight; Na2C03 1.13% by weight. (2) Black Pigment No. 1 - Cr, Spinelled Cu (3) Oxide Black Pigment No. 2 - Ni, Mn, Fe, Cr Oxide Spinel. Example 3 The black coating ceramic composition of Example 2 was applied by serigraphy, to a glass for artifacts. Very clear print details were observed. The glass with the coating applied, was subjected to cooking in a conventional manner at a temperature of 1200 ° F to 1250 ° F (from 648.9 to 676.7 ° C) for four to six minutes, obtaining a product- or

Claims (9)

1. coated artifact glass, with crisp print details. The ceramic coating composition, black, can also be used in the coating of automotive glasses, such as windshields and rear windows. NOVELTY OF THE INVENTION 1. A medium intended to be used in the preparation of a ceramic coating composition, said medium comprising a solvent base in an amount of approximately 50% to 99% by weight; characterized in that the medium contains approximately 0.1 to 50% by weight of pantothenol.
2. 2. A medium according to claim 1, characterized in that it comprises: approximately 50 to 99% by weight, of a solvent base; 0 to about 45% by weight, of a binder; about 0.1 to 50% by weight of pantothenol; 0 to about 15% by weight, of a plasticizer; and 0 to about 15% by weight, of a viscosity modifier.
3. 3. A medium according to claim 2, characterized in that the solvent base is tripropylene glycol methyl ether, and the viscosity modifier is hydroxypropyl cellulose.
4. 4. A medium according to claim 3, characterized in that it also comprises a dispersant and an odor masker.
5. 5. A ceramic coating composition comprising a glass frit and an organic medium, characterized in that the medium Organic m is a medium as defined in claim 1.
6. 6. A composition according to claim 5, characterized in that it also contains a pigment.
7. 7. A composition according to claim 5, characterized in that it also contains a finely divided electrically conductive metal.
8. 8. A method for the preparation of a coated glass substrate with a ceramic coating composition, characterized in that it comprises applying to at least a portion of a glass substrate, a coating ceramic composition according to claim 5, and subsequently subjecting said coated substrate to baking, in order to melt said coating to said substrate.
9. 9. A coated glass substrate, characterized in that it is produced according to the process of claim 8. EXTRACT OF THE INVENTION An improved medium to be used in the preparation of ceramic compositions for coatings. The improvement consists of the use of pantothenol as a rheological modifier in the medium. Under protest to tell the truth, the best known method for putting the present invention into practice is the one described in the description of this application. In testimony of which we sign the present in: Mexico, D. P.r to December 6, 1995. CERDEC AKTIENGESELLSCHAFT KERAMISCHE FARBEN.