TRILOBAL YARNS FOR APPLICATION ON DENTAL FLOSS, DENTAL FLOSS INCLUDING THE SAME AND USE OF TRILOBA YARNS IN THE MANUFACTURE OF DENTAL FLOSS

Abstract

The present invention refers to yarns made of hollow trilobal cross section filaments, comprising from 90 to 99% of polypropylene, and between 1 and 10% of other polyolefin resins, for the application on dental floss. This invention additionally refers to the production process of the yarns made of hollow trilobal cross section filaments. This invention additionally refers to dental floss comprising hollow trilobal cross section filaments, and the use of hollow trilobal cross section filaments for the manufacture of dental floss. The yarn described in this invention has linear density or title in the range from 400 to 1200 dtex, and it is twisted with a twist level from 10 to 160 twists per meter.

Claims

1. A yarn comprising filaments with hollow trilobal cross section, characterized by comprising from 90 to 99% polypropylene and between 1 and 10% of other polyolefin resins, for the application on dental floss.

2. The yarn according the claim 1, characterized by comprising 95% polypropylene and 5% polyolefin resin.

3. The yarn according to claim 1, characterized in that the polyolefin resin is polyethylene.

4. The yarn according to claim 1, further comprising additives chosen between dyestuffs and pigments.

5. The yarn according to claim 1, wherein the yarn has a linear density or title in the range from 400 to 1200 dtex, and the yarn is twisted with a twist level between 10 and 160 twists per meter.

6. Dental floss comprising a hollow trilobal cross section filament comprising 90% to 99% polypropylene and between 1% and 10% other polyolefin resins.

7. (canceled)

8. A method of making the yarn of claim 1 by multifilament melt spinning using synthetic resin as raw material, comprising: feeding raw material to an extrusion melt spinning machine, wherein the raw material is polypropylene pellets, and the extrusion melt spinning machine comprises an extruder, gear metering pumps, spinnerets, quench cabinets, spin finish applicators, draw rollers, tangling nozzles, and a winding system; melting the polypropylene pellets in the extruder with the addition of a pigment masterbatch to obtain a molten mass, wherein the pigment masterbatch comprises the other polyolefin resin; pumping the molten mass throughout the spinnerets, to generate a product in form of continuous hot molten filament yarn; cooling the hot molten filament yarn with air to turn it solid, and subsequently lubricating, drawing, and tangling the cooled filament yarn with air, and finally winding the cooled filament yarn onto paper tubes; and twisting the yarn with 10 to 160 twists per meter.

Description

DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a picture of a hollow trilobal cross section made by microscope.

DETAILED DESCRIPTION OF THE INVENTION

[0017] A real example of the present invention is a yarn made of continuous filaments with hollow trilobal cross section, containing from 90 to 99% polypropylene (PP), and between 1 to 10% other polyolefin based masterbatches (pigments), being preferred 95% polypropylene (PP) and 5% polyolefin resin, particularly polyethylene (PE), for the application on dental floss.

[0018] The dental floss object of this invention comprises yarns made of continuous filaments with hollow trilobal cross section containing from 90% to 99% polypropylene (PP), and between 1 to 10% other polyolefin based masterbatches (pigments), being preferred 95% polypropylene (PP) and 5% polyolefin resin, particularly polyethylene (PE).

[0019] Some advantages presented by the dental floss object of the present invention are: Improved capacity of bacterial plaque removal due to the filaments cross section shape, and additionally this improvement is enhanced more 40% when the yarn is additivated with special pigments for this application, like: Pigment Blue 15:3 C.I. 74160, Pigment Green 7 C.I. 74260, Pigment Red 149 C.I. 71137 and Pigment White 6 C.I. 77891; Increased wax and flavours pick up capacity; Better comfort and ease of use for the consumer, due to the increased filament flexibility provided by the hollow cross section; Less weight (for the dental floss producer, who sells the dental floss by meter), provided by the hollow cross section yarn, having more bulk and less weight.

[0020] Beyond the cited advantages, the dental floss object of the present invention deforms elastically its cross cut section when it is forced to pass between tight interdental space, making easier and more comfortable the cleaning procedure made by the consumer, when compared with the traditional dental floss made with solid cross section filaments.

[0021] The yarn object of the present invention has a linear density or title in the range between 400 and 1200 dtex, it is twisted with a twist level between 10 and 160 twists per meter, in order to increase its strength during its use. The twisted yarn has an increased protection against the breaking or tearing of individual filaments or even the whole yarn when it is subjected to friction. Specifically to the subject of the present invention, said friction occurs between the yarn and the teeth, during the tooth cleaning procedure made by the consumer, when the yarn is forced to pass through interdental space.

[0022] Another statement of the present invention is the hollow trilobal filament production process. This referred process comprises the following steps: [0023] multifilament melt spinning using synthetic resins as raw material; [0024] to feed the extrusion melt spinning machine with raw material in form of polypropylene in pellets; [0025] to melt the polypropylene in the extruder and, when applied, in this step is dosed the pigment masterbatch (1 to 10%), to obtain coloured yarn in different colours; [0026] to pump the molten mass throughout the spinnerets, to generate a product in form of continuous filament yarn; [0027] cool down the hot molten filaments with air to turn it solid, and subsequently lubricate, draw, tangle the filaments with air, and finally wind the yarn onto paper tubes; [0028] to twist the yarn with 10 to 160 twists per meter.

[0029] The present invention additionally refers to the use of hollow trilobal cross section filaments for the manufacture of dental floss.

EXAMPLES

[0030] Find below the technical data of 2 dental floss products experimentally produced:

TABLE-US-00001 TABLE 1 Dental Floss Item Unity 500/160 700/320 Composition 100% PP 100% PP Linear Density (Title) dtex 490 to 520 690 to 720 Number of filaments Number 160 320 Cross section hollow hollow trilobal trilobal Breaking strength N >18 >26 Tenacity cN/dtex >3.5 >3.5 Elongation % 20 a 40 20 a 40 Twist level twists/meter 65 65