FILS TRILOBES POUR L`APPLICATION SUR DE LA SOIE DENTAIRE, SOIE DENTAIRE COMPRENANT LES FILS ET UTILISATION DES FILS DANS LA FABRICATION DE SOIE DENTAIRE

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

Abrégé anglais

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.

Revendications

CLAIMS
1. An 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 any one of claims 1 to 2, characterized in that the
polyolefin resin cited is polyethylene.
4. The yarn according to any one of claims 1 to 3, characterized by the fact
that it comprises additives chosen between dyestuffs and pigments.
5. The yarn according to any one of claims 1 to 4, characterized in that it
has
a linear density or title in the range from 400 to 1200 dtex, and it is
twisted with a twist
level between 10 and 160 twists per meter.
6. Dental floss, characterized by comprising a hollow trilobal cross section
filament, as described at any one of the previous claims 1 to 5.
7. Use of a filament yarn with hollow trilobal cross section as described in
any
one of claims 1 to 5, characterized by being for the manufacture of a dental
floss, as
described in claim 6.
8. A method of making the yarn of claims 1 to 5 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 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;
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- 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.
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Description

TRILOBAL YARNS FOR APPLICATION ON DENTAL FLOSS, DENTAL FLOSS
INCLUDING THE SAME AND USE OF TRILOBAL YARNS IN THE MANUFACTURE
OF DENTAL FLOSS
FIELD OF THE INVENTION
[0001] The present invention is about a continuous filament yarn with trilobal
cross
section for application on dental floss, and a dental floss manufactured with
this
mentioned yarn.
BACKGROUND OF THE INVENTION
[0002] Bacterial Plaque, also known as Dental Plaque, Microbial Plaque, Oral
Biofilm,
Dental Biofilm or Bacterial Plaque Biofilm, is a biofilm formed by bacteria
and food
residue that is formed on the surface of the teeth, this plaque is the main
cause for dental
decay and gum disease. This plaque in the early stage is a sticky colourless
deposit, but
If this plaque is not removed daily, it grows and hardens forming the tartar.
Dental Floss
and/or Dental Tape are important oral hygiene tools to avoid the Bacterial
Plaque.
[003] There are many types of Dental Floss known. Between them there are
continuous
synthetic yarns, made of monofilannents of PTFE (polytetrafluorethylene), and
there are
Dental Floss made of continuous synthetic yarns made of PA (polyamide)
multifilaments,
which is made of several filaments bunched together in one single cable, to
make a
single yarn. The PA dental floss can be waxed or not, with a wide variety of
flavours. The
PTFE monofilaments slide easier between the teeth than the multifilaments,
which
sometimes can shred or rip. The tapes are flatter and thinner, with the goal
to reach a
wider area, but it has more difficult to reach the interdental space.
[0004] Trilobal filaments and synthetic fibres are very well known for its
textile
application. Filaments and fibres with trilobal section are known for its
increased gloss
and brightness when compared to the same filaments and fibres with round cross
section, and this is the main purpose to use this trilobal cross section,
because the light
reflection in the yarn surface is less diffuse , the light reflected is more
oriented due to
the trilobal yarn surface geometry. The hollow cross sections are used to
reduce the
textile material density, and to improve the thermal insulation property,
because the
internal channel inside the hollow filaments and fibres is filled with air.
[0005] In the case of the present invention, the purpose of the hollow
trilobal cross
section is not the same of those mentioned above. In the Dental Floss
application, it is
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proved that the trilobal cross section is more abrasive when compared with the
traditional
round cross section, and this property improve the efficiency of the bacterial
plaque and
food residues removal from the interdental space.
[0006] The hollow trilobal cross section yarn has more volume when compared
with a
traditional solid round cross section yarns and even when compared with solid
trilobal
cross section yarn. It has been proved that this increased volume improves the
bacterial
plaque and food residues removal from the interdental space.
[0007] US2939201 refers to novel trilobal synthetic filaments and fibres
having improved
optical properties and improved resistance to soiling when incorporated in
textile
materials.
[0008] US4770938 refers to a trilobal, synthetic fibre, intended for use in
carpets, having
an axially extending hole in each lobe, the total cross-sectional area of the
fibre being
about 5 to 12 percent void, said fibre cross-section having a modification
ratio of between
about 2 to 3, and an arm angle of about 150 to 450, so that a fibre having
improved bulk,
soil hiding and resiliency is apparent in a carpet having face fibre of said
fibre.
[0009] EP750691 refers to a melt spinning process and the nylon hollow
filaments and
yarns made by such process which includes extruding molten nylon polymer
having a
relative viscosity (RV) of at least about 50 and a melting point (TM) of about
210 DEG C.
to about 310 DEG C. from a spinneret capillary orifice with multiple orifice
segments
providing a total extrusion area (EA) and an extrusion void area (EVA) such
that the
fractional extrusion void content, defined by the ratio [EVA/EA] is about 0.6
to about 0.95,
and the extent of melt attenuation, defined by the ratio [EVA/(dpf)S], is
about 0.05 to
about 1.5, in which (dpf)S is the spun denier per filament, the (dpf)S being
selected such
that the denier per filament at 25% elongation (dpf)25 is about 0.5 to about
20 denier;
withdrawing the multiple melt streams from the spinneret into a quench zone
under
conditions which causes substantially continuous self-coalescence of the
multiple melt
streams into spun filaments having at least one longitudinal void and a
residual draw
ratio (RDR) of less than 2.75; and stabilizing the spun hollow filaments to
provide hollow
filaments with a residual draw ratio (RDR) of about 1.2 to about 2.25.
[0010] US2011044916 refers to a dental floss comprising a basic amino acid or
salt
thereof. The said dental floss may be produced from nylon, or from
polytetrafluoroethylene (PTFE or Teflon ), polypropylene, polyethylene,
styrene
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butadiene copolymers, or a combination of them. The polymer is melted and
extruded
into thin strands, like the dental floss described in this invention.
[0011] US4646766 refers to a dental tape made from polypropylene. The tape may
be
made by extruding a polypropylene film in strip form onto chilled take-off
rollers and then
roll embossing the film by means of hardened steel rollers.
[0011] Brazilian patent application PI0905828 refers to a dental floss with
improved
dental cleaning efficiency and improved adaptation to the interdental space,
by the
presence of axial flexible saliences, so that by the dental floss movement
between teeth,
the secondary yarn can penetrate, and by flexible expansion of the dental
floss, reach
interdental spaces that a traditional dental floss could not reach.
SUMMARY OF THE INVENTION
[0013] The present invention refers to a yarn with hollow trilobal cross
section for the
application on dental floss, as well as the application of trilobal filaments
on dental floss.
[0014] The present invention additionally refers to dental floss comprising
hollow trilobal
cross section filaments.
[0015] The present invention additionally refers to the production process of
the hollow
trilobal cross section filaments.
DESCRIPTION OF THE DRAWINGS
[0016] Figure 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
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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 al. 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:
- multifilament melt spinning using synthetic resins as raw material;
- to feed the extrusion melt spinning machine with raw material in form of
polypropylene in pellets;
- 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;
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,
- to pump the molten mass throughout the spinnerets, to generate a product
in
form of continuous filament yarn;
- 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;
- to twist the yarn with 10 to 160 twists per meter.
[0023] The present invention additionally refers to the use of hollow trilobal
cross section
filaments for the manufacture of dental floss.
[0024] EXAMPLES
Find below the technical data of 2 dental floss products experimentally
produced:
Table 1
Dental Floss
Item Unity 500/160 700/320
Composition - 100% PP 100% PP
490 to 690 to
Linear Density (Title) dtex 520 720
Number of filaments Number 160 320
hollow
trilobal
hollow
Cross section - trilobal
Breaking strength N > 18 > 26
Tenacity cN/dtex > 3,5 > 3,5
Elongation cyo 20 a 40 20 a 40
Twist level twists/meter 65 65
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