US2108953A - Flexible package for hydrocolloid impression materials - Google Patents

Description

Feb. 22, 1938. w. J. VAN ROSSEM FLEXIBLE PACKAGE FOR HYDROCOLLOID IMPRESSION MATERIALS Filed June 5, 1936 AITTORNEYS.

Patented Feb. 22, 193% I UHTED STATES PATENT Fries FLEXIBLE PACKAGE FOR HYDROCOLILOIID IMPRESSION MATERIALS Walter J. van Rossem,

- assignor to Surgiden West Los Angeles, Caliii.,, t, Ltd, West Hollywood,

. 2 Claims. This invention relates to a method of forming an advantageous package construction in which a moisture-containing material may be stored or marketed, and to the package construction thus 5 formed, and pertains particularly to a package for a plastic moisture-containing impression compound, comprising a container or envelope of moisture-impervious coating material of high mechanical strength at ordinary temperatures i and marked flexibility at temperatures near the boiling point of water and a body of moisturecontaining hydrocolloid impression composition enclosed within said container or envelope.

This application is a continuation-in-part of 35 my earlier application Serial No. 57,397, filed J anuary 3, 1936.

One of the important objects of the invention is to provide a package which may be easily and inexpensively prepared and which will preserve 90 a moisture-containing hydrocolloid composition without loss of moisture, for an indefinite period.

A further important object is to provide a package of the character described which com-- prises a moisture-impervious envelope structure capable of elastic deformation at temperatures adjacent or in the neighborhood of the boiling point of water.

A further object of the invention is to provide a novel and advantageous methodof forming a package for a moisture-containing hydrocolloid' composition.

The package of the present invention is primarily adapted for enclosing dental impression compositions having a reversible hydrocolloid 35 base. These compositions are in general semirigid when cool and must be heated to render the same fluent for use. Compositions of this general type are described in U. S. Patent No.

1,672,776 and in the two U. S. patents of Laurence 40 E. Harrison, Nos. 2,021,058 and 2,020,311. Prior to the present invention these compositions have been marketed in the form of cylinders about one inch in diameter and 'four inches long wrapped in a tinfoil cartridge or the like, or as described 45 in U. S. Patent No. 1,977,580, enclosed in a cellulosic envelope which is in turn enclosed in a moisture-impervious envelope such as a glass bottle or a wax coating. One of the objections to the use of foil wrappers has been that, in ad- 50 dition to a slight loss of moisture, the composition became discolored due to contact with the metal container, which prejudiced the user, and one of the principal objections to the package described in Patent No. 1,977,580 is the cost of the 55 double envelope'type of package as well as the danger of rupture or fracture of the exterior envelope which permits loss of moisture from the composition through the cellulosic envelope. According to the present invention a continuous moisture-impervious envelope coating is provid- 5 ed for a body of such impression composition which adequately protects the same from contamination and preserves the moisture content thereof, such envelope coating being of a material which is of high mechanical strength at ordinary temperatures but readily capable of elastic deformation at elevated temperatures whereby the packages may be immersed in water and heated to render the contained composition fluent after which the package may be kneaded to homogenize the composition and render the same suitable for use, without danger or rupture of the envelope during the kneading operation.

The coating material should be one which, even at the elevated temperatures at which the contained impression composition is handled to render the same fluent, retains a high degree of mechanical strength, and preferably also remains substantially moisture-impervious. The coating material is preferably one having a relatively high mechanical strength at ordinary temperatures, a melting point somewhat in excess of 100 C. and relatively resilient and capable of elastic deformation at temperatures in the neighborhood of 100 C.- The ability of the material to elastically deform at the high temperatures should persist to an important degree during cooling from adjacent 100 C. to in the neighborhood of to C. as itis common practice in dental technique to continue the kneading of the heated 3.3 composition until the temperature thereof has dropped to a point such that it may be inserted within the mouth of a patient without undue discomfort. Numerous materials are available,

, for the fabrication of this envelope, such as the -10 vinyl resins, among which may be listed the commercially available Koroseal (a polymerized vinyl halide) which has a melting point in the neighborhood of 116 C. or combination solutions of cellulosic compounds and a moisturei5 proofing material such as rubber, resins, resinous gums, and high melting point waxes.

The continuous envelope for the above-described moistureecontaining hydrocolloid lmpression composition may be formed by any one of a number of procedures. An advantageous procedure is that of forming an elongated cylindrical or other suitably shaped body of the hy drocolloio composition by extrusion, molding or the like, and immersing the formed body in a fluid bath of the material of which the envelope is to be formed, as by passing such body through said bath, so as to form a continuous coating of the envelope material on the exposed surface of the hydrocolloid body, cutting the coated body into desirable lengths and immersing the end portions of the cut lengths thereof in a fluid bath of coating material, as by dipping, and allowing the thus completely coated bodies to thoroughly dry. Alternatively, the hydrocolloid composition may be cut or otherwiseformed into bodies of the desired length and such bodies immersed, as by endwise dipping, into a fluidbath of-the envelope material so as to form a coating on one end portion thereof, the coating on such end allowed to solidify, the bodyinverted and again immersed to a point somewhat above the end of the previously formed coat, so as to forma coating' over the other end portion overlapping the end of the first formed coat, and the coating then allowed to solidify and dry to form a continuous envelope over the entire surface of the body.

The accompanying drawing illustrates packages formed by the above procedures and referring thereto:

Fig. 1 is a partly broken-away perspective view of a package formed by the continuous coating procedure, before the coating material is placed over the end portions thereof;

Fig. 2 is a view corresponding to Fig. 1, showing a finished package, partly broken away longitudinally;

Fig. 3 is a broken-away perspective view of a body of impression composition coated on one end by the double dipping procedure;

Fig. 4 is a view corresponding to Fig. 3, showing a complete package formed by the double dipping procedure; and

Fig. 5 is a view corresponding'to Fig. 4, showing a package prepared from a preformed capsule or thimble sealed at one end by a dip coat.

Referring to the drawing, the form of pack age shown in Figs. 1 and 2 may be formed by extruding a cylindrical body of the hydrocolloid composition into a fluid bath of coating ma-, terial, to form an exterior coating I. The hydrocolloid composition is then cut into suitable lengths such as shown at 2 and the ends of the formed sticks are then dipped into a fluid bath of coating material to a sumcient distance to form caps 3 at each end of the stick,, which overlap and integrally bond with the end portions of the coating I, as shown at 3'. The exterior coating I may advantageously be formed by anodic deposition from a latex dispersion or the like, in which event the end caps 3 may be formed from a'solution such as a composite celluloid-rubber solution, or from a solution of rubber.

The form of package shown in Figs. 3 and 4 may be produced by forming the hydrocolloid composition into sticks 4 of suitable length, which are dipped endwise into a fluid bath of the coating material, to form an elongated cap.

5 at one end, and then dipped into said bath at the other end to a suflicient distance to form a cap 6 which overlaps and seals integrally with the cap 5 intermediate the ends of the package, as at 1.

As shown in Fig. 5, a prefabricated capsule or thimble 8 may be employed, into which the impression composition may be cast as at 9, and the open end sealed by dipping into a fluid bath of coating composition to a suflicient distance to form a cap portion l0 after the manner of the form illustrated in, Figs. 1 and 2.

In the fabrication of the form of package shown in Figs. 1 and 2, I may employ a mixture of celluloid and rubber in a suitable solvent, such as may be formed from arr-intermixture of two equal volumes of cyclohexanol or cyclohexanol acetate in which from 10% to 30% by weight of celluloid and raw rubber have been respectively dissolved, the mixture being preferably evaporated to a thin honey-like consistency. Alternatively, I may use a commercially available mixture containing the above-mentioned vinyl resin (Koroseal), such as that material marketed under the name of Korolac which comprises a mixture of the polymerized vinyl halide and a suitable solvent which may be brought to a true solution by heating to somewhat above 100 C.

Where the celluloid-rubber mixture is employed, it'will be necessary to allow the coating l to dry to some extent before the end-dipping is practised, and in this connection it is preferable to cut the extruded bodies into the short lengths 2 after the coating I has solidified or hardened to a sufiicient extent that the lengths may be handled without damage to such coating. Immediately after cutting into the desired lengths, the ends may be dipped to form the caps 3, and there will thus be no significant loss in moisture from the composition during the package-forming operation. Alternatively, the extruded hydrocolloid composition may be passed through alternate hot air blasts and sprays of the coating composition, in a process of building up an adequate layer of moisture-impervious fllm coating, in which case the coated material may be handled in the end-dipping procedure promptly' after the coating I is formed.

In the fabrication of the form shown in Figs. 3 and 4 I prefer to employ a coating material which will solidify or gel at a rapid rate, so that the two' ends of the body of hydrocolloid composition may be coated without the lapseof much time, so that the evaporation of moisture from the composition will be kept at a desirable minimum. For this type of package, therefore, I prefer to employ a material of the nature of the above-mentioned Korolac, which, being a solution of the resin Koroseal only at-a relatively high temperature, will gel out on contact with the hydrocolloid composition and form a continuous envelope over the dipped area, which may be handled in the dipping of the other end substantially immediately after the first end is dipped.

As a specific example of the practise of the invention in the formation of a moisture-impervious envelope of the resin -Koroseal", I heat a body of "Korolac containing approximately 10% Koroseal to a temperature of approximately 130 C., and dip one end of a preformed stick of the hydrocolloid composiiton into the fluid body, withdraw the stick promptly, invert the same, and dip-the other end into the fluid body to a point overlapping the edge of the previous dipping, and then withdraw the stick and allow it to dry.

The preformed stick of hydrocolloid composition will ordinarily be at ordinary atmospheric temperature when dipped, and wili have a chilling effect upon the fluid coating material in contact therewith, causing such material to be solidified or jelled on the surface of the stick. Due to the nature of the Korolac, this solidified condition is such that the stick may be immediately handled without damage to the coating, although the dipped package must be allowed to dry for several hours before shipment, to allow the solvent to escape from the gel coating, and permit the coating to dry and form a thin, tough, moisture-impervious membrane.

brane from 0.005 to 0.009 thick. Where heavier coatings are desired, multiple dipping may be practised in such manner as to form a plurality of material, in the production of membranes in excessof 0.01" in thickness.

Where a preformed capsule or envelope is employed, as in the form shown in Fig. 5, the capsule may be formed of any of the coating materials above mentioned, and the open end of the capsule may be sealed in the described manner or, in the event that a, material such as Koroseal is employed, the open end-may be causedto extend beyond the body of contained composition and heat-sealed as'by means of a hot iron or the like.

Other methods of forming the package may be apparent to one skilled in the art. For example, as described in my copending application, the envelope may be formed by inserting a wire into a body of the hydrocolloid composition and dipping In. general, a single dip coat will be adequate, forming a memsuperimposed thicknesses of coating 7 a body of moisture-containing hydrocolloid composition and an enclosing envelope completely surrounding said body, said enclosing envelope comprising a film of polymerized vinyl halide resin.

2. A moisture-impervious package comprising an elongated body of moisture-containing hydrocolloid composition, a film of moisture-impervious coating material enclosing one end of said body and extending along the length thereof toward the other end, a film of moisture-impervious coating material enclosing the other end of said body and overlapping and integrally sealed to said first-named film at a position intermediate the length of said body, said moisture-impervious coating material comprising a polymerized vinyl halide resin.

WALTER J. VAN ROSSEM.

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