US2624163A - Method of making colored gelatin capsules - Google Patents

Description

METHOD OF MAKING COLORED GELATIN CAPSULES Filed April 22, 1948 IN VEN TOR. f. JT/AA/ Patented Jan. 6, 1953 METHOD OF MAKING COLORED GELATIN CAPSULES Frank E. Stirn; Pearl River, N

16., assignor to a corporation ot-Mainc Application Aprili22, 1948;.SeriaLNo. 22;598

' My invention relates-to-improvementsin gela tin capsules;particularly'those which are formed film? pertain-- ing-nrore particularly-to methods of coloring of at least' part of the-'surface'- of such capsules in fi'om continuous strips of gelatin such areas as -may" be considered desirable.

In'thepast soft gelatin capsules have" been produced fromgelatin filmby'stretching the-filmto a desiredform and encapsulatingtherein the Ith'as been customary to form:

desiredcontents. such gelatincapsules in'- someinstan'ce's, inclear,

colorless gelatin and in others from colored or pigmented gelatin; as desired forpurposes of makingthe 'gelatincapsule more attractive; Such methods-of coloration are' -described' for example in-the Patent'-No; 730L643 to Anthony M. Hance. Additional metho'ds are disclosed in the Patent No.- 1,134,156-to- H; R -Plant'en, which again de scribeszfsoft gelatin capsules being made from colored film; iii-this instance disclosing two -dif-- different portions of the surface by making the capsule fromtwosheets ferent colors of film f or' of two differentcolors.

My invention relates twavery simple-and-more method of forming caps'ules which-:- comprises' casting: the gelatin any convenient:

convenient manner, ofi any: convenient color, asi ma'y" be desired} l and 1 treatingfz thefilm after having: been casitlibut. preferably. before the capsuleformation, .with .a.. solu operatorschoice-to for-m1;capsules invwhich-vari ous a portionsvmay be 1 colored; It is: convenient bytmy-tmethodi'to form: capsules .imwhichthe: two

difierentvportions;of.gelatin strip: from "which the capsulesis formedvare.differently colored, but additionallyl itispossible: by methodyto form capsules: in which trade-names or identifying marks may be; placed onpthe-=surfaceiof the capsules for purposesv ofidentifications of origin, giving; information to the-physician, or patient, or such: other, purposes as- 'may bee -deemed dc,- sirablet or: necessary;

The methods of forminga the gelatin fi1m= and ment onother pigment is present-to render-the 1e: dye; insa suitable solvent. whereby the surfacesonly: of desired portions of thergelatinlfilmxis colored: in accordancewithwthe from the: followingdescription, accompanying drawings and appended claims;

- Figure 1 is aside elevation of a coloring roll= stack which may be used inaccordance with this invention-to color agelatin film.

Figure 2 isa front viewof 1 the roll stack; in section; showing the gelatin filmpassingthere" over taken, along" line 22-' of Figure 1'.-

Figure 3 isa view of a contacting-roll certain portions of the surface of which are. raisedtogive selective coloring to the gelatin film.

Figure 4 is a view of a typical capsule showing one-half of the; capsule being Y colored differently than the remainder.

Figure 5 shows a capsule,lthe-entiressurfaeexof which is colored;

Figure 6 is I a figureiofta; capsule; showinga portion of the: gelatin: capsule which: dOBSTIlOt have a surface dye thereon, and the: remainder adyed' with: a str'ipladpattern;

Figure 'Zais. a-tgelatincapsule a portioni-ofathe' surface :-,of which is so colored-asztocshow-Lade sired inscription, case for examplezthat'produced' by the rollerof Figure; 3.

Difierent'methodsofforming: the gelatin can he -used in connectionwithmy method-of coloring. There is shown, accordingly; only a portion of the gelatin'film I I, as it isfed- -from aconveyor feed be1t-l2 overa dyeingassembly I3- to-atake-up roller 14. Thev conveyor feed belt and take-up roller are not part of this invention and are shown diagrammatically only as they may be any of those previously. known;

For mypurpose ofdyeingthefilm it is necessary-thatadye roll mechanism-be usedfsuchothat a sufficient and notexcess portion ofdye; is con tinuously transmitted to the gelatin filmr continiuously and:uniformly. v

In such .Ltraditional printing procedures as are used in printing paper webs; a'safor example a newspapen, it is customary to transfer ink :from an inking: roll to a" type surface? and from-there tosthe paper; with the paper at the time: of printing being pressed firmly againstthe surface-of theJtype: by" some form of-backing:roll; Such' a formofibackingtroll would not be satisfactorywith a gelatin film because the film is fragile and extremely sensitive to pressure.

Whereas a very light pressured guide roll or guide belt could be used to assist in positioning the gelatin film against the film contacting dye roll it has been found that by suitable choice of dye roll material, dye, and solvent therefore, it is possible merely to use the pressure of the gelatin film caused by its weight or the slight tension which is necessarily present in the film as it is handled to cause the gelatin film to rest against the surface of the roll sufficient for transfer of the dye. This is shown clearly in Figure 1 in which the dyeing assembly [3 includes a' support frame [5 adaptedto be suitably supported in spaced relationship to the film, preferably by adjustable means, as for example the support slot is and clamping bolts H. Supported thereby is the dye trough l8 adapted to contain the desired dye in a suitable solvent as later described. If desired it is within the scope of'this invention to supply the dye trough IS with a float system for a continuous level maintenance by means of an automatic system or with a supply tube and feed glass whereby the dye level may be maintained by the operator. Such dye level maintenance is not particularly critical and may be most simply controlled by the operator adding additional dye solutions as is required to the trough from such supply container as is convenient. Suitably journaled in the dye trough I8 is a partially submerged roller 19, so called because a portion of the surface of this roller is submerged beneath the liquid level of the dye solution during a portion of its rotation. This roller may be journaled either on pinions, or a shaft, so as to be freely rotatable and so as not to bind from the action of the dye and its solvents.

For purposes of dyeing gelatin film it has been found that a Micarta roll journaled on a brass shaft is particularly suitable. The brass does not readily corrode. The Micarta roller slides freely upon the brass shaft 20 with a minimum of friction, is easily wet by the dye solutions, and transfers an adequate and effective but not excessive quantity of the dye as it is so rotated. The. Micarta used may be prepared by molding a phenolformaldehyde type resin (Bakelite) with a linen or cotton fabric, in accordance with conventional practice. It is essential that the smooth gloss surface obtained from a well polished mold be broken; a convenient method of doing-this is to grind the surface of the mold with an abrasive grinding wheel or to turn the surface of the roll as for example on a standard metal working lathe, whereby the surface of the roll is smooth and uniform but yet not glazed. Journaled above, parallel to, and in contact with the submerged roll is a dye transfer roll 2| which is suitably journaled on a shaft above and parallel to the submerged roll [9. While not necessary,-it may be desirable that the center to center-distances of these rolls be adjustable so that the rolls may be turned down rather than replaced when worn.

As shown in Figure 1, there may be journaled above the dye transfer roll an embossed roll 22. This embossed roll is supported by an embossed roll bracket 23 on each side, which in turn is supported by a bracket screw 24 about which it may rotate and which positioned by collar 25 may be clamped by a clamp screw 26. As shown, the embossed roll may be clamped in a vertical position as shown in solid lines in Figure 1, or dropped to a non-functioning position as shown in dotted lines in Figure 1.

Both the dye transfer roll 2| and the embossed roll 22 may well be made from Micarta, although other suitable materials may be used. As shown in Figure 2, the embossed roll consists of a series of raised peripheral areas so that a series of parallel lines are dyed upon the surface of the film. A suitable inscription or legend may be dyed upon the surface of the film by the introduction of a suitably embossed rule as shown in Figure 3. Either the major or minor portion of the inscription may be the raised portion which transfers the dye to the surface of the gelatin film.

For best results it has been found most desirable. that a dye rather than a pigment be used for the coloring of the surface and it has been found desirable that the dye used possess certain characteristics. For the purposes of human consumption it is essential that the dyes used be non-toxic. Dyes approved for food, drug and cosmetic use are particularly suitable because those approved by the Federal Drug Administration or other government agencies for use in food and drugs have been already checked by toxicity studies and additional studies are not necessary to permit their use for human consumption. Other dyes may be chosen for other purposes. If the capsules are used for other than human consumption a very broad choice of dyes may be made.

It is desirable that the dye solvent used be reasonably volatile, so as to insure easy removability; be Water miscible, so that it will penetrate into the surface of the gelatin film and will not form a repellent layer thereon, be cheap, easily obtainable; and it must dissolve the specific dyes being used. For standard gelatin films it has been found that methyl alcohol and ethyl alcohol are particularly useful. Higher alcohols such as isopropyl, propyl, the butyls, benzyl, etc., may be usedbut because they are less volatile it is more difiicult to remove them and because the higher alcohols are less water soluble there is more of a tendency for the dye not to transfer smoothly into the gelatin film and instead to remain encrusted on the surface. Polyhydric alcohols are in general not sufiiciently volatile for commercial utilization. Acetone may be used but it has a tendency to dry too quickly and not give a sufliciently deep or clear print and seems to leave the dye mainly on the surface. Water, itself, does not dry sufficiently quickly and tends to run on the surface of the film giving feathering rather than clear lines.

The lower alcohols, particularly methyl and ethyl, are the most satisfactory as they are good solvents for many of the drug and cosmetic dyes, they transfer reasonably clear to the surface of the gelatin film, do not encrust on the surface, and under normal conditions give a smooth, rapid and efiective transfer which may in part be due to the rapid dilfusion of the alcohol into the gelatin film.

Petroleum ether was used as a solvent but dried too quickly and did not appear to be sufficiently water miscible to transfer the dye into the gelatin film properly. It isoperable, but not a preferred embodiment.

Example '1.

D and C Violet No. 1 in methyl alcohol. The 5 dye tmugnWas-filIed-so.athatzthersubmergcd roll. was: nearly .coveredyand, the capsule. machine; operatedwith theggelatinzifilmi contacting; the; dye transfer roll? 21. A- smooth, uniform, even violet coloration was given to the surface, only of the; gelatin strip. The alcohol evaporated sufiiciently rapidly so that no complications: were'encounteredin the operation of the machine; and: capsules were:produced with: the entire; surface dyed violet.

' Example 2 The dye known commercially as F, D and C Red..No. 3" was prepared as; a %l solution-in ethyl alcohol. Theembossed roll. 2'2: was-raised to, operating position, an' embossed. roll consisting; of; raised; adjacent strips, as. shownin; Figure 2;. being; used. Thecapsule machinerwas operated, giying smooth,;uniform,.alternately colored strips; on-the; surface of they gelatinrfilm, and, was so. operated thatonly the gelatin film forming one-.- half, of the: capsule. was colored by running'only one-half the forming. film over the. dye roll. Smooth, evenlydyed bars were formed on the surface of the film with bright, sharp, clear edges. The dye was readily and evenly transferred to the-surface. of the film. Capsules of this type are shown in Figure 6.

Example 3 The. dye known as D and C. Violet No. -l"was dissolvedto the extent. of 5.% in water. The-embossed; roll was dropped and the;device operated with. the dye transfer roll in contact with the surface of the film. An..even.transfer of. color took: place. but the additional water introduced onto the; film causedthefilm to dry so: slowly as to make it necessary to operate the capsule forming machine at lessthan the. otherwise most desirable speed.

Example 4 'A. 1% solution in acetone-was prepared of .D and'C' Violet No. 2,," and the dye mechanism operated with the dye transfer roll'contacting the surface of a single film. The acetone dried too quickly so the imprint was not as deep or as clear or as uniform as with alcohol as a solvent but a capsule which was commercially satisfactory was obtainable as illustrated in Figure 4.

Example 5 A 5% solution of F, D and C Red No. 3.was dissolved in ethyl alcohol. An embossed roll with an inscription thereon as shown in Figure 3, was placed in the embossed roll bracket and raised to contact the surface of the film. A smooth, uniform dyed print was obtained on the surface whereby an inscription such as a name and trademark were smoothly embossed on the surface of the gelatin film forming capsules with the name of the contents dyed in the surface thereof.

Example 6 The machine was rearranged so that two independent coloring mechanisms were present, in the first of which was placed a 5% solution of F, D and C Green No. l in ethyl alcohol, with the dye transfer roll in contact with the surface of the film. A short distance therefrom was placed the second dyeing assembly with an embossed roll containing a trade inscription raised on the surface thereof. This trough was filled with a 5% methyl alcohol solution of D and C Red No. 28. A timing chain was connected to the embossed roll 22 so that it was driven in timed relationship; to. the. capsule: forming; .dles: whereby: can-- sules were formed with. the trade insignia uni-r formly printed in red on. a green background and accurately registered: on; the. surface of the.

filled gelatin capsules.

Example I 7 A 1% solution of F, D and C Red No. 3" in ethylalcohol Was substituted butthe-apparatus otherwise. operated the same as, in Example 1.

Arather light color. coat was formed, but entirelyuniform and satisfactory for purposeswhere pale colors are desired.

Emample" 8 A 1% solution of F, D and C Green No. 1-

was prepared: in isopropyl alcohol and placed in the dye. trough with the gelatin film contacting;

the transfer roll. The gelatin film. was inverted by. running over a pair of rolls having a half twist and an additional coloringmechanismwas capsules. The capsules could be identified as to.-

origin by slicing them in two and reading the name of the maker on the internal surface.

In general, it will be found that the dyes will print evenly and uniformly. However, with certain gelatin formulations particularly those in which an unusually high percentage of a plasticizer such as glycerine is used, the dyes will eX- hibit a tendency to bleed after the printing, per-- haps because such plasticizer acts as a solvent for the dye and permits itto run. Under such circumstances, a dyemust be selected such that due to its lower solubility in glycerine it will not bleed to an undesirable extent. With the harder formulations, such as are preferred for the powder filled capsules, such troubles with bleeding are not normally encountered, and clear, sharp lines are the rule. If a high oil content is present in the capsule, with a high glycerine content, it will be found that the oil remains in place, but if a low glycerine mix is used, some of the oil may tend to penetrate the gelatin, and in such cases, it may be desirable to coat the inside of the capsule with an impervious coating such as a mesin to prevent the oil from blurring the color mes.

Other dyes may be used. The publication of the Federal Security Agency, Food and Drug Administration, Service and Regulatory Announcements, Coal Tar Color Regulations list such acceptable colors. For those skilled in the art the dye index lists the colors of the dye, the solvents in which they dissolve, whether or not they are water compatible and their toxicity. Any dye which is acceptable from the standpoint of toxicity and which meets solubility characteristics is acceptable and may normally be readily selected from the dye indices without the necessity of experimentation. It is desirable that the dyes be at least somewhat water soluble so that they will go into the gelatin film more readily and will not tend to cake on the surface thereof. The numher, the depth, and configuration of dye patterns may be varied in accordance with the choice of the operator. The dyes on the capsules form particularly convenient methods of identifying the contents and the manufacturer according to predetermined codes and standards.

It is the intention of the inventor to reserve for himself and those in privity with him the distinctive colors of blue and yellow. Others may of course desire to use other color combinations.

It is convenient to use a gelatin film containin a pigment to prevent light from passing entirely through the capsule and to conceal the contents with a yellow dye in the base film and on the surface of which the desired patterns or insignia may be readily printed.

, Whereas there has been described particularly the use of two and three roll mechanisms, to those in the art it will be obvious that four, five and six rolls could be used'with the dye being transferred for the purposes of getting thinner coats. Additionally the roll stack could be arranged so that the final film contacting roll is above, below or at either side of the trough. Where several rolls are used or where the bearings are not substantially frictionless it may be desirable to have the film contacting roll power driven to prevent any pulling or slipping on the surface of the film. Whereas rolls of Micarta have been particularly described, rolls of soft wood, sintered glass, sintered metals, unglazed porcelain, well compacted felt, cloth, paper pulp, brass, bronze, stainless steel, etc., may all be used within the scope of my invention. Such rolls as type metal, steels, etc., must be clean so the ink will wet the surface to work properly. An ofi-Set transfer roll may be used, as may lithographic rolls, if roll surfaces are selected that possess the well known requirements for these specific purposes. 7

Whereas in the past it has been necessary to use different gelatin supplies to get difierent colored films in the capsule, my method of coloring the film as cast insures that both gelatin films used for multiple colored capsules will possess essentially the same characteristics, as they arecast at the same time. The films will be homogeneous. It will be unnecessary to worry about having residue of one color left over and in general operating conditions will show the marked improvement that comes from simplified operations.

Having therefore set forth certain preferred embodiments, illustrating certain aspects of my improvements, as my invention I claim:

The method of forming an edible soft gelatin capsule with visible insignia which includes the steps of dissolving a non-toxic alcohol-soluble dye in a. lower alcohol, transferring the thus formed solution from a bath to a pattern roll containing upstanding portions and marking a wet, freshly cast self-supporting soft edible gelatin film by contacting said film with upstanding portions of said pattern roll, thereby transferring portions of the solution to the desired portions of the wet, freshly cast, edible soft gelatin film, causing the alcohol to evaporate therefrom, and promptly forming edible soft gelatin capsules from portions of the thus marked strip.

FRANK E. STIRN.

REFERENEES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 228,362 Kwaysser June 1, 1880 758,501 Von Beust Apr. 26, 1904 1,087,843 Smith Feb. 17, 1914 1,701,811 Keller Feb. 12, 1929 1,855,525 MacArthur July 19, 1930 1,861,827 Titus June 7, 1932 2,037,825 Salfisberg Apr. 21, 1936 2,323,582 Weckesser July 6, 1943 OTHER REFERENCES Printing Inks, by Ellis, 1940, Reinhold Publishing (30., 330 West 42nd Street, New York city, page 350. (Copy in Div. 17.)

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