US 2982234 A
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printing or the like.
Unitcd cs P t i io METHOD OF PRINTING WAXED PELLETS, AND PRINTING INK No Drawing. Filed Oct. 4, 1957, Ser. No. 688,15l.
5 Claims. (Cl. 107-54) This invention relates to a method of applying markings to relatively'small objects such as capsules or pellets, hereinafter referred to generically as pellets, and to an ink for application to such pellets. More particularly, this invention hasto do with the printing of indicia on Wax-coated pharmaceutical pellets.
Inthe pending patent application of Amos Ackley, Serial No. 388,891, filed October 28, 1953, now abancloned, it is pointedout that it is frequently desired to place a manufacturers trademark or some other marking on pharmaceutical pellets, for purposes of ready identification. Although certain solid pellets have heretofore been molded or cast with the manufacturers marking molded thereon, a casting process is not applicable to pellets having a core or body portion consisting of a medical orpharmaceutical formula and surrounded by a hard shell or sugar. Such sugar coated pellets are usually formed with smooth outer surfaces, and it is then necessary to apply a marking to that surface by Often such printing is accomplished by applying a shellac coating to the surface of the sugar coating and then applying to the shellac coating an ink which has a shellac base. Due to the presence of shellac in both the ink and thecoat the ink adheres tenaciously to the coat and produces a highly acceptable product, However, the nature of the shellac surface is considered inferior by somepharmaceutical manufacturers, in view of its lack of polishor luster and also because of the absence of free-sliding characteristics.
Many manufacturers of pharmaceutical pellets consider it extremely desirable to apply a (carnauba) wax coating to each pellet, such coating being capable of t 'aking on a high polish, and also having very desirable sliding properties when the pellet is processed in a pellet marking machine such as the machine referred to in the co- 2,982,234 Patented May 2,
ink containing coacting proportions of cyclohexane and ammonia, which ingredients coact with one another and with the other ingredients of the ink to produce a marking of exceptional clarity and legibility, which marking penetrates into the wax layer and is not readily removed by scratching or rubbing.
After the printing operation, applying an ink as dis,- closed above, the pellet is dried for an extended period in order to provide the desired degree of hardness. 'I'he cyclohexane and ammonia evaporate as the drying pro-' ceeds. If desired, the drying operation can be accelerated by the application of'heat to a limited degree.
' Preferably in accordance with this invention, the ink consists essentially of a purified shellac, referred to as .confectioners glaze, mixed with selected quantities of ethyl alcohol and water white butyl alcohol, containing cyclohcxane and ammonia in substantial amounts, and also containing carbon black and a selected dye such as D and C blue dye #6 (Color Index Number K7024).
Preferably, the ink utilized in accordance with this method consists essentially of the following ingredients in parts by weight as indicated below: I
Parts by weight Confectioners glaze (purified shellac) mixed with Dye (D and C Blue #5,, Color Index N0. K7024) 0.9 2.1
'The confectioners glaze referred to above preferably consists of a purified shellac which is free of arsenic and lead, and which is also free ofwax. The ethyl alcohol,
like the confectioners glaze, must be fit for human conwith the purity of the other ingredients of the ink.
pending patent application referred to above. However,
the presence of the wax coating seriously complicates the printing operation because conventional inks having shellac bases do not print well on the wax coat, or adhere to it, and the markings readily rub off even after they have been dried on the waxed surface. g
It is' accordingly an object of this invention to provide a method of applying a marking to a pharmaceutical pellet having a: waxed sugar coating. Still another object of this invention is to provide an ink which'may be wax.
applied to a waxed sugar-coated pellet and which adheres tenaciously thereto. Still another object is to provide an ink and a method of applying the same to a waxed,
Cyclohexane in purified form is used. It has'the ability, when'co'mbined with ammonia, to cut through the carnauba wax which is applied to the sugar surface much better than any other non-toxic solvent of which we are aware.
The ammonia is conveniently purchased as 26 Baum (U.S.P.) ammonia, and apparently not only serves as an emulsifying agent for the wax, but coacts with the cyclohexane to provide an exceptionally rapid cutting of the It is believed that the ink, formulated as disclosed above, cuts rapidly through the entire thickness of the carnauba wax coating and reaches the surface of the sugar coating. v
The primary purpose of the ethyl alcohol and white butyl alcohol contained'in the confectioners glaze is to control the rate of evaporation of the ink. If the ink evaporates too rapidly, the ink does not have the opportunity to penetrate through the wax, whereas too slow evaporation results in a situation where the wet ink offse to other objects which the pellet contacts. It will accordingly be appreciated that the relative proportions of ethyl alcohol and white butyl alcohol are subject to considerable variation, depending upon the particular requirements of the specific process at hand. Preferably, however, the mixture of confectioners glaze with ethyl alcohol is a so-called 8 pound cut. An 8 pound cut" consisted 8.23 pounds of shellac plus alcohol in each gallon of alcohol, and consists of 57.4% by weight shellac and 48.6% by weight of ethyl alcohol. Similarly, although the amount ofbutyl alcohol may vary widely, it-is preferred to use a 6 pound cut of confectioners glaze in water white butyl alcohol. A 6 pound cut" consists of 8.00 pounds of total mixture per gallon of alcohol, and consists of 44.6% by weight shellac and 55.4% by weight butyl alcohol.
It will accordingly be appreciated that the essential ingredients of the ink utilized in the process of this invention are as follows: I
Parts by Weight Shellac (dissolved in an appropriate mixture of ethyl and butyl alcohol) 28-68 cyclohexane 8-22 Ammonia (26 Baum) 6-14 Dye or pigment 0.9-4.2
Not only does the invention as disclosed herein have the advantage that an exceedingly good printing job may be done on pellets having wide varieties of shapes and forms, but it has also been found that pellet printing machines of the type referred to in the Ackley application operate much better utilizing a waxed pellet as distinguished from a shellac coated pellet. The waxed pellet has a smooth, slippery surface which readily lends itself to the variety of pellet-handling operations that are performed by the automatic pellet printing machine, and it has been found that the capacity of almost any pellet printing machine presently in use can be greatly increased by first wax coating the pellets and then printing them in accordance with the process of this invention.
Although this invention has been described with reference to specific embodiments, it will be appreciated that variations may be made without departing from the scope of the invention. For example, equivalents may be substituted for those method steps and chemical compositions disclosed herein, method steps may be reversed so far as the mixing of the ingredients of the ink is concerned, and certain features of the invention may be utilized independently of the use of other features, all within the spirit and scope of the invention as defined in the appended claims.
Having thus described our invention, we claim:
1. In a method of preparing a printed edible pellet, the steps which comprise wax coating the surface of the pellet, and then penetrating the wax coating and printing said surface with a non-toxic edible ink containing in combination ammonia and cyclohexane in a ratio within a range of about 6 to 14 parts of ammonia calculated as 26 Baum and about 8 to 22 parts by weight of cyclohexane, and permitting the ink to dry.
2. In a method of preparing a printed edible pellet, the steps which comprise coating the pellet with wax, and then penetrating the wax coating and printing said surface with a non-toxic ink consisting essentially by weight of about 28-68 parts by weight of edible shellac, about 8-22 parts by weight of cyclohexane, about 6-14 parts by weight ammonia (calculated as 26 Baum) and about 0.9-4.2 parts by weight edible dye, and permitting the ink to dry.
3. In a method of preparing a printed pharmaceutical pellet having a sugar coating, the steps which comprise applying camauba wax to the sugar surface, polishing the waxed surface, and then penetrating said waxed surface and printing said sugar surface by applying to said wax surface a non-toxic edible ink, said ink consisting essentially of about 19-45 parts by weight of a confectioners glaze consisting of about 57.4% by weight of purified shellac and about 48.6% by weight of ethyl alcohol, about 9- 23 parts by weight of a confectioners glaze consisting of about 44.6% by weight of purified shellac and about 55.4% by weight of white butyl alcohol, about 8-22 parts by weight cyclohexane, about 6-14 parts by Weight of ammonia (calculated as 26 Baum) about .9-2.1 parts by weight of purified carbon black, and about .9-2.1
. parts by weight edible dye, and permitting the ink to dry.
4. 'A non-toxic ink for marking a waxed coated edible pellet beneath the waxed-coated surface thereof, said ink consisting essentially of about 19-45 parts by weight of a confectioners glaze consisting of about 57.4% by weight of purified shellac and about 48.6% by weight of ethyl alcohol, about 9-23 parts by Weight of a confectioners glaze consisting of about 44.6% by, weight of purified shellac and about 55.4% by weight of white butyl alcohol, about 9-23 parts by weight of cyclohexane, about 6-14 parts by weight ammonia (calculated as 26 Baum), and about .94.2 parts by weight dye.
5. A Wax-penetrable non-toxic ink for directly printing the surface of a sugar pellet having a wax surface which ink consists essentially of the following ingredients in the relative weight proportions indicated below:
, Parts by Weight Confectioners glaze (approximately 57.4% by weight of purified shellac and 48.6% by weight of ethyl alcohol) 19-45 Confectioners glaze (approximately 44.6% by weight purified shellac and 55.4% by weight water white butyl alcohol) 9-23 cyclohexane 8-22 26 Baum ammonia 6-14 Purified carbon black .9-2.1 Edible blue dye .9-2.l
References Cited in the file of this patent UNITED STATES PATENTS 200,589 Warner Feb. 19, 1878 504,064 Field Aug. 29, 1893 1,492,454 Halo Apr. 29, 1924 1,701,811 Keller Feb. 12, 1929 1,907,203 Wruble May 2, 1933 2,245,100 Bernstein June 10, 1941 r 2,450,959 Heinecke Oct. 12, 1948 2,865,810 Sanders Dec. 23, 1958 FOREIGN PATENTS 376,413 Great Britain July 14, 1932 OTHER REFERENCES Chemical Abstracts 43,6817c (1949).
Chemical Abstracts 47,3462a (1953).
Rowell: The Art of Coating Tablets," Drug and Cosmetic Industry, vol. 63, No. 4, October 1948, pp. 459, 460 and 549-51.
Clarkson: Tablet Coating," 1951 (pp. 34-58 especially relied upon).