U.S. patent application number 09/956897 was filed with the patent office on 2002-08-29 for toothbrush with highly tapered bristles having superior flexibility and method of manufacturing the same.
Invention is credited to Kwon, Young-Jun.
Application Number | 20020116778 09/956897 |
Document ID | / |
Family ID | 19706169 |
Filed Date | 2002-08-29 |
United States Patent
Application |
20020116778 |
Kind Code |
A1 |
Kwon, Young-Jun |
August 29, 2002 |
Toothbrush with highly tapered bristles having superior flexibility
and method of manufacturing the same
Abstract
Disclosed herein is a toothbrush with tapered bristles and
method of manufacturing such toothbrushes. The toothbrush is
characterized in that the tapered end of each bristle is 0.02 mm or
less of diameter. The bristle is tapered starting at a position of
3.5 mm or less from an end, and is made of polyethylene
terephthalate or polybutylene terephthalate. The method of this
invention consists of the steps of dipping 3.5 mm portions from
ends of monofilaments for toothbrushes into erosive chemicals such
as sulfuric acid or sodium hydroxide until the dipped portions of
the monofilaments are completely eroded, neutralizing the shortened
monofilaments prior to rinsing and drying them, and implanting the
shortened monofilaments on a toothbrush. Thereafter, the shortened
monofilaments are ground using a 240# mesh paper at 2600 to 2700
rpm for 3 to 10 sec, a 320# mesh paper at same speed for 3 to 10
sec, and a 400# mesh paper at same speed for 3 to 10 sec. The
toothbrush of this invention enjoys advantages of proper
flexibility and softness, improved feeling while brushing, and
excellent scaling ability.
Inventors: |
Kwon, Young-Jun; (Paju,
KR) |
Correspondence
Address: |
JACOBSON HOLMAN PLLC
400 SEVENTH STREET N.W.
SUITE 600
WASHINGTON
DC
20004
US
|
Family ID: |
19706169 |
Appl. No.: |
09/956897 |
Filed: |
September 21, 2001 |
Current U.S.
Class: |
15/167.1 ;
15/207.2; 300/21; 428/401 |
Current CPC
Class: |
A46D 1/0276 20130101;
A46D 1/00 20130101; Y10T 428/2976 20150115; A46B 2200/1066
20130101; Y10T 428/298 20150115 |
Class at
Publication: |
15/167.1 ;
15/207.2; 300/21; 428/401 |
International
Class: |
A46B 009/04; A46D
001/04; A46D 009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 23, 2001 |
KR |
2001-9217 |
Claims
What is claimed is:
1. A toothbrush with highly tapered bristles having superior
flexibility, wherein each of said bristles is made of polyethylene
terephthalate or polybutylene terephthalate, and tapered starting
at a position of 3.5 mm or less from an nd thereof, with a tapered
end having a diameter of 0.02 mm or less.
2. The toothbrush of claim 1, wherein the tapered end of each of
the bristles is 0.01 mm or less in diameter.
3. The toothbrush of claim 1, wherein each of the bristles is
tapered starting at a position of 3.0 mm or less from the end of
the bristle.
4. A method of manufacturing a toothbrush with highly tapered
bristles having superior flexibility, comprising the steps of:
dipping 3.5 mm-long portions from ends of monofilaments for
bristles into erosive chemicals such as sulfuric acid or sodium
hydroxide until the dipped portions of the monofilaments are
completely eroded; neutralizing the shortened monofilaments prior
to rinsing and drying them; attaching the shortened monofilaments
on a predetermined portion of a toothbrush; and grinding the
shortened monofilaments with the use of a 240# mesh paper rotated
at 2600 to 2700 rpm for 3 to 10 sec, a 320# mesh paper rotated at
same speed for 3 to 10 sec, and a 400# mesh paper rotated at same
speed for 3 to 10 sec.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to, in general, a toothbrush
with tapered bristles and a method of manufacturing such
toothbrushes, in particular, to a toothbrush with highly tapered
bristles having high flexibility and a method of manufacturing the
same.
[0003] 2. Description of the Prior Art
[0004] A conventional monofilament for bristles of toothbrushes is
made of nylon. The nylon monofilament bristles have the advantages
of proper resilience and flexibility, but are disadvantageous in
that they are highly water-absorbent and are easily deformed. The
nylon monofilament bristles are not soft because they must be thick
in order to maintain desired flexibility. Generally, the nylon
monofilament bristles are each rounded at their ends in order to
prevent the gums from being injured during brushing, as shown in
FIG. 1.
[0005] Polyester compounds, such as polybutylene terephthalate or
polyethylene terephthalate, may be used as material for the
monofilament bristles of toothbrushes. In comparison with nylon
bristles, the polyester compound bristles have advantages of a
lower price, good durability, and lower water-absorptivity, and so
such polyester compounds are preferable for bristles of
toothbrushes. However, the monofilament bristles made of such
polyester compounds are too stiff and inferior in their
flexibility, and may damage or injure the gums. The polyester
compounds have been typically used as the materials for bristles of
inexpensive disposable toothbrushes, or the polyester compound
bristles used in combination with nylon bristles, as a way to
reduce the cost.
[0006] To avoid the above disadvantages, there was proposed a
process of tapering the ends of such polyester compound bristles
into a needle-shape. Conventionally, such tapering of the bristles
was done mechanically by the blade of a knife or an abrader, as
shown in FIG. 2. But, it is almost impossible to overcome the above
disadvantages of the polyester compound bristles by such
mechanically and slightly tapering the ends of the bristles.
[0007] Many studies have been made to avoid such disadvantages. For
example, reference may be made to a patent owned by the inventor of
the present invention, Korean Patent No. 130932 (hereafter, refer
to `first prior art`), which discloses a method of tapering a
monofilament for bristles using chemicals. The method disclosed in
the Korean Patent comprises the steps of (i) cutting a monofilament
made of polybutylene terephthalate or polyethylene terephthalate in
such a way that the length of a primarily cut monofilament is
longer than a target length by 1 to 4 mm, (ii) vertically dipping
the surplus portion of the primarily cut monofilament into a
sulfuric acid in order to remove the surplus portion of the
primarily cut monofilament, in addition to tapering the end of the
monofilament to form the target length of a resulting filament.
[0008] According to the first prior art, highly tapered bristles
are obtained, each of which is tapered starting at a position of 4
to 10 mm from an end of the bristle, with the free end of the
bristle being 0.01 mm in diameter, as shown in FIG. 3.
[0009] The first prior art provides bristles with a somewhat
desired softness by reducing the stiffness of the polyester
compound filaments such as polybutylene terephthalate filaments,
and easily removing an odontolith from a periodontal pocket by
highly tapering the end of the monofilament, as shown in FIG.
3.
[0010] However, the first prior art exhibited the following
problems:
[0011] 1) A toothbrush with bristles made by the method of the
first prior art felt too soft by some users familiar with
conventional toothbrushes with nylon bristles. Such users thus
determine the brushing effect of the toothbrushes to be not
desirable.
[0012] 2) Since the highly tapered bristles are manufactured using
chemicals, the tapering process is too difficult as the processing
conditions such as a concentration of chemicals, a temperature, and
the duration of dipping are difficult to precisely control.
Therefore, the ends of the highly tapered bristles are not uniform.
As a result, defective products are produced in 50% or more of the
time.
[0013] To avoid these problems, another reference may be made to a
patent owned by the inventor of the present invention, Korean
Patent No. 261658 (hereafter, referred to as the `second prior
art`), which discloses a method of tapering a monofilament for the
bristles of toothbrushes. This method comprises the steps of (i)
primarily cutting a filament made of polybutylene terephthalate or
polyethylene terephthalate into bristles having a target length,
(ii) dipping the bristles into a strong alkali or acid solution at
the temperature of 100 to 180.degree. C. until the bristles
shorten, (iii) rinsing the bristles with water, (iv) drying the
bristles, (v) attaching the bristles on the head of a toothbrush,
(vi) cutting the free ends of the bristles of the toothbrush to 0.5
to 1.5 mm, and (vii) grinding the ends of the bristles until the
ends are 0.04 to 0.08 mm in diameter. A cross sectional view of a
tapered bristle according to the second prior art is illustrated in
FIG. 4.
[0014] Overcoming the low flexibility of the bristles according to
the first prior art, the bristles of the second prior art, however,
suffer from disadvantages in that it is difficult to remove the
odontolith from a periodontal pocket because the diameter of the
bristle ends in the second prior art, which ranges from 0.04 to
0.08 mm, is undesirably larger than that of the bristles in the
first prior art, and the price of the bristles according to the
second prior art is cheaper in that it is 25% of the price of the
bristles in the first prior art.
SUMMARY OF THE INVENTION
[0015] It is therefore an object of the invention to avoid the
disadvantages of the prior arts, and provide highly tapered
bristles with appropriate flexibility suitable for preventing
injury to the gums and removing an odontolith from a periodontal
pocket.
[0016] It is another object of the present invention to manufacture
such highly tapered bristles without wasting bristle material.
[0017] It is still another object of the present invention to
provide highly tapered bristles which are comfortable to a user
while toothbrushing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above and other objects, features and other advantages
of the present invention will be more clearly understood from the
following detailed description taken in conjunction with the
accompanying drawings, in which:
[0019] FIG. 1 is a cross sectional view of a bristle having a
rounded end according to the prior art;
[0020] FIG. 2 is a cross sectional view of a tapered bristle
according to the prior art;
[0021] FIG. 3 is a cross sectional view of a highly tapered bristle
according to the prior art;
[0022] FIG. 4 is a cross sectional view of a tapered bristle having
superior flexibility according to the prior art; and
[0023] FIG. 5 is a cross sectional view of a highly tapered bristle
having superior flexibility according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] The present inventors have conducted extensive studies,
resulting in the finding that the above objects could be
accomplished by the provision of tapered bristles, each of which is
tapered starting at a position of 3.5 mm or less from an end of the
bristle, with the free end of the bristle being 0.02 mm or less in
diameter.
[0025] The advantages of the invention will be described with
reference to the accompanying drawings.
[0026] Referring to FIG. 3 according to the first prior art, the
bristles should be tapered starting at a position of 4 to 10 mm,
typically 7 to 8 mm from an end of the bristle in order to allow
the tapered end of the bristle to be 0.01 mm of diameter. This is
because the whole bristle is eroded, not only at the ends of the
bristles, when they are being dipped into chemicals, thereby
reducing the flexibility of the bristles.
[0027] With reference to FIG. 4 according to the second prior art,
the bristle is tapered starting at a position of 4 to 5 mm from an
end of the bristle, with the free end of the bristle being 0.04 to
0.08 mm in diameter. In comparison to the bristles with long
tapered ends of first prior art, the bristles with short tapered
ends according to the second prior art has increased flexibility,
but it is difficult for the bristle of the second prior art to
remove an odontolith from a periodontal pocket because the end of
the bristle is relatively thick, as described above.
[0028] According to the present invention, tapered bristles are
obtained, each of which is tapered starting at a position of 3.5 mm
or less, preferably 3 mm or less from an end of the bristle, with
the free end of the bristle being 0.02 mm or less, preferably 0.01
mm or less in diameter, as shown in FIG. 5
[0029] As described above, in comparison with a bristle of first
prior art, the bristle of this invention has advantages in that the
odontolith can be easily removed from periodontal pockets because
the end of the bristle has a small diameter. This bristle also
improves the feeling while brushing because it is better than that
of the second prior art in flexibility. Furthermore, a thin end of
this bristle provides softness, so that the bristles are less
likely to cause damage to the gums while toothbrushing.
Accordingly, the bristles of the invention can overcome the
disadvantages of the prior arts.
[0030] A method of manufacturing the bristles of the invention,
comprises the steps of dipping a portion of 3.5 mm length from an
end of a monofilament for bristles into erosive chemicals such as
sulfuric acid or sodium hydroxide until the dipped portion of the
monofilament is completely eroded; neutralizing the shortened
monofilament prior to rinsing and drying it; implanting such
shortened monofilaments on the head of a toothbrush; and grinding
the implanted monofilaments with a 240# mesh paper at 2600 to 3000
rpm for 3 to 10 sec, a 320# mesh paper at same speed for 3 to 10
sec, and a 400# mesh paper at same speed for 3 to 10 sec, thus
forming the resulting bristles.
[0031] Thereby, tapered bristles with each free end ranging from
0.005 mm to 0.02 mm in diameter are obtained, each of which are
tapered starting at a position of 2.8 mm to 3.5 mm from the base
end of the bristle, without wasting materials.
[0032] The following examples are for illustration purposes only
and in no way limit the scope of this invention.
EXAMPLE
[0033] Into a 1,000 ml beaker with a sandbath were charged 50% NaOH
solution filled 1 cm from the bottom of the beaker. Then, the
temperature of the solution was increased to 120.degree. C. After
that, polybutylene terephthalates (520) filament 0.2 mm in
diameter, manufactured by TORAY CO., Japan, were cut into filaments
30 mm in length. Thereafter, 3.5 mm end portions of the bundled
filaments were dipped vertically into the NaOH solution. After 18
minutes passed from the start of dipping, the ends of the filaments
were not at the point of melting so filaments were not shortened,
but after 19 minutes from the start of the dipping, the ends of the
filaments were at the point of melting so that the filaments were
shortened. After 19 minutes had passed from the start of dipping,
the tapered filaments were removed from the solution. Subsequently,
the opposite ends of the filaments were tapered in the same manner
as described above, thus producing bristles.
[0034] Afterward, highly tapered filaments, each of which was
tapered starting at a position of 3.0 mm from an end of the
filament with the end being 0.01 mm in diameter, were obtained by
the steps of fully rinsing the filament bundles with water; drying
the bundles after binding the filaments with a rubber band;
attaching the filaments on the head of a toothbrush; and grinding
the filaments by use of a cutting and grinding machine with a 240#
mesh paper rotated at 2700 rpm for 5 sec., a 320# mesh paper at the
same speed for 5 sec., and a 400# mesh paper at the same speed for
5 sec.
[0035] After 10 adults brushed their teeth with the use of the
resulting toothbrushes, the toothbrushes were evaluated as
excellent toothbrushes in regard with flexibility, softness,
feeling while brushing, and scaling ability.
Comparative Example
[0036] The procedure of the above Example was repeated except that
the dipping time was set to 18 minutes and the step of grinding
with the use of a 320# mesh paper was omitted.
[0037] Tapered filaments with the end being 0.04 mm in diameter
were obtained, each of which was tapered starting at a position of
3.5 mm from an end of the filament.
[0038] After 10 adults brushed their teeth with the use of the
resulting toothbrushes, the toothbrushes were evaluated lowly in
comparison with those of Example in regard with flexibility,
softness, feeling while brushing, and scaling ability.
[0039] As described above, the toothbrush of the invention provides
proper flexibility and softness, and easily removes an odontolith
from a periodontal pocket, with bristles creating a good feeling
for the user while brushing. Also, the toothbrush of the present
invention prevents waste of materials and reduces the defective
proportion of products during production of toothbrushes, different
from toothbrushes having conventional highly tapered bristles.
[0040] Although the Examples of the invention have been disclosed
for illustrative purposes, those skilled in the art will appreciate
that various modifications, additions and substitutions are
possible, without departing from the scope and spirit of the
invention as disclosed in the accompanying claims.
* * * * *