US 3247857 A
Description (OCR text may contain errors)
April 26, 1966 M. s. KANBAR 3,247,857.
DENTAL FLOSS Filed June 23, 1965 1 N VEN TOR.
United States Patent 3,247,857 DENTAL FLOSS Maurice S. Kanbar, 2 E. 75th St, New York, N.Y. Filed June 23, 1965, Ser. No. 466,229 7 Claims. (Cl. 132-93) This application is a continuation-in-part of application Serial No. 276,564, filed April 29, 1963 now abandoned. This invention relates to a dental floss made of exceptionally soft material, the floss having a smooth surface and a high tensile strength whereby the teeth and gums may be cleaned efliciently and without injury thereto.
Dental floss is used to dislodge food particles and other foreign material wedged between the teeth. The use of floss supplements the toothbrush, for brushes cannot penetrate the constricted region between adjacent teeth. Since dental floss is forced between the teeth and makes contact with the gums, to avoid damage it is important that the floss surface be free of abrasion. At the same time, the floss must be strong, for it is subject to tension when forced between the teeth by the user.
Among the materials generally used for dental floss are multi-strand silk and cotton or nylon yarns which are rendered smooth by applying a coating of a waxlike substance, such as parafiin or solid polyethylene glycols. While the use of strands adds to the strength of the floss, the rupture or unravelling of any strand when the floss is used, results in a surface discontinuity which is injurious to the user.
Accordingly, it is the main object of this invention to provide a dental floss which is of exceptionally soft material, having a smooth surface entirely free of abrasion, the floss nevertheless being of high tensile strength.
More specifically, it is an object of the invention to pro vide a dental floss of superior quality formed by loosely twisting a tape of an oriented polymer, such as a polyethylene or polyamid into a helix forming a small compressible tube.
For a better understanding of the invention, as well as other objects and further features thereof, reference is made to the following detailed description to be read in conjunction with the accompanying drawing, wherein:
FIG. 1 is a perspective view of the tape used in making the floss;
FIG. 2 shows the tape after stretching;
FIG. 3 shows the tape after twisting to form floss; and
FIG. 4 shows the compression of the floss as it passes between adjacent teeth.
Referring now to the drawing, and more particularly to FIG. 1, the starting material for the dental floss is a smooth film ltl of uniform thickness formed from an extruded polymer, such as Saran, polyethylene, polyesters, or polyamides. Such films in broad widths are produced by the melt extrusion process, and for present purposes a fine film of approximately 0.00015" thick is used, which is slit into a tape of approximately one inch in width. Alternatively, the film may be extruded from a die directly in the desired tape Width.
The tape is then passed through snub orienting or drawing rolls constituted by feed rolls and draw rolls operating at different speeds, the speed ratio therebetween determining the extent to which the tape is stretched. Stretching of the tape serves to orient the molecular structure of the film and thereby increase its tensile strength. The yarn may be cold or hot drawn. In hot-drawing, heat is supplied to the drawing point, the drawing load of the tape being thereby lowered more than the breaking load, enabling a greater draw ratio to be achieved.
In accordance with the present invention, the tape is stretched to approximately 3 times its initial length to produce a ribbon 11, as shown in FIG. 2, whose width is about one-half that of the initial tape 10 and about half as thick. The ribbon is much stronger than the unstretched tape and is very soft.
The ribbon 11 is then twisted approximately 1 to 3 turns per inch to produce a floss 12 having the desired characteristics. Because of the loose twist, the ribbon forms a helix which produces a continuous hollow tube of very small diameter. As shown in FIG. 4, when the tubular and very soft floss 12 passes in the very narrow passage between teeth T and T the floss yields and the tube is compressed. Thus the floss is both soft and compressible and when passed through a constricted dental region tends to yield to avoid injury to dental surfaces. On the other hand, the exceptional strength of the floss and its naturally smooth qualities render it highly suitable for its intended purpose.
Because the tape is loosely twisted, this creates crevices in the floss which tend to catch and dislodge debris from between the teeth when the floss is passed therethrough.
While there has been shown and described a preferred embodiment of improved dental floss in accordance with the invention, it will be appreciated that many changes and modifications may be made therein without, however, departing from the essential spirit of the invention as defined in the annexed claims.
What is claimed is:
1. A dental floss constituted by an extruded polymer ribbon which is stretch-oriented to increase its strength and which is loosely twisted into a helix forming a hollow and compressible tube.
2. A floss as set forth in claim 1, wherein said ribbon is approximately one-half inch wide and of a thickness in the order of .000075".
3. A floss as set forth in claim 1, wherein said film is formed of a polyamide.
4. A floss as set forth in claim 1, wherein said film is formed of a polyethylene.
5. A floss as set forth in claim 1, wherein said film is formed of a polyester.
6. The method of making dental floss, comprising the steps of extruding a polymer film of uniform thickness, slitting said film into a tape having a width of about one inch, stretching said tape to orient its molecular structure to form a ribbon, and twisting said ribbon into a helix to form a hollow and compressible tube.
7. The method of making an abrasion-free and strong dental floss, comprising the steps of:
(a) extruding a polymer into a tape having a width of about one inch and a uniform thickness not exceeding .00015 of an inch,
(b) stretching said tape to orient its molecular structure and to form a relatively narrow ribbon whose width and thickness are substantially smaller than that of the tape, and
(c) twisting said ribbon loosely about one to three turns per inch into a helix to form a hollow tube constituting a compressible floss having exceptional strength and smoothness.
References Cited by the Examiner UNITED STATES PATENTS 1,149,376 8/1915 Leonard et a1 132-93 1,832,604 11/1931 Wupper l32-93 2,337,834 12/1943 Peters 13293 2,772,205 11/1956 King l32--93 RICHARD A. GAUDET, Primary Examiner.