U.S. patent application number 13/488552 was filed with the patent office on 2012-09-27 for artificial breast implant provided on the surface threof with silicon open cell foam layer, and method for producing the same.
Invention is credited to Won Seok Yu.
Application Number | 20120245685 13/488552 |
Document ID | / |
Family ID | 44059787 |
Filed Date | 2012-09-27 |
United States Patent
Application |
20120245685 |
Kind Code |
A1 |
Yu; Won Seok |
September 27, 2012 |
ARTIFICIAL BREAST IMPLANT PROVIDED ON THE SURFACE THREOF WITH
SILICON OPEN CELL FOAM LAYER, AND METHOD FOR PRODUCING THE SAME
Abstract
Disclosed are an artificial breast implant in which the surface
thereof is formed or modified with a silicone open cell (open pore)
foam layer, and a method for producing the same. More specifically,
disclosed are an artificial breast implant that has a surface
including an open cell foam layer made of silicone and thus
minimizes side effects such as in vivo rejection, which may occur
after implantation of the implant into the body, in particular, the
occurrence of capsular contracture to achieve superior
biocompatibility and safety, and a method for producing the
same.
Inventors: |
Yu; Won Seok; (Daejeon,
KR) |
Family ID: |
44059787 |
Appl. No.: |
13/488552 |
Filed: |
June 5, 2012 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
PCT/KR2010/001826 |
Apr 12, 2010 |
|
|
|
13488552 |
|
|
|
|
Current U.S.
Class: |
623/8 ;
427/2.24 |
Current CPC
Class: |
B29C 44/005 20130101;
B29K 2083/005 20130101; B29C 41/14 20130101; B29L 2031/7532
20130101; A61F 2/0077 20130101; B29C 67/202 20130101; A61F 2/12
20130101 |
Class at
Publication: |
623/8 ;
427/2.24 |
International
Class: |
A61F 2/12 20060101
A61F002/12 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 19, 2009 |
KR |
10-2009-0112022 |
Claims
1. An artificial breast implant provided on the surface thereof
with a silicone open cell foam layer, the surface of which is
formed or modified with a silicone open cell (pore) foam layer.
2. The artificial breast implant according to claim 1, wherein the
open cell (open pore) foam layer has a three-dimensional net
structure with a uniform or non-uniform thickness.
3. A method for producing an artificial breast implant provided at
the surface thereof with a silicone open cell foam layer,
comprising: a silicone dipping operation of dipping a breast-shaped
mold in a silicone solution to obtain an artificial breast shell; a
drying and curing operation of drying an artificial breast shell
adhered to the mold using a drier, followed by curing to obtain a
silicone artificial breast shell; an open cell formation operation
of forming an open cell foam layer on the surface of the dried and
cured shell; an artificial breast shell acquisition operation of
forming an aperture on the bottom of the artificial breast shell
adhered to the mold and provided with the open cell foam layer and
removing the artificial breast shell from the mold; and an implant
formation operation of adhering a silicone film including a leakage
prevention film to the aperture to fill the aperture.
4. The method according to claim 3, wherein the formation of the
open cell foam layer includes: dipping the dried and cured mold
provided with the shell in a silicone solution and taking out the
mold; scattering or spraying a solid particle or powder with an
appropriate size to the surface of the shell such that the silicone
solution film loses flowability; and scattering or spraying a solid
particle or powder to the surface of the shell.
5. The method according to claim 4, wherein the solid particle or
powder is not dissolved in the silicone solution and does not
affect physical properties of the silicone solution, and is
dissolved in a solvent and removed.
6. The method according to claim 5, wherein the solid particle or
powder is sodium chloride, ammonium carbonate, ammonium phosphate,
or ammonium chloride.
7. The method according to claim 5, wherein the solvent is
water.
8. The method according to claim 4, wherein the organic solvent is
readily miscible with the silicone solution.
9. The method according to claim 8, wherein the organic solvent is
benzene, toluene, xylene or a derivative thereof.
10. The method according to claim 9, wherein the organic solvent is
xylene.
11. The method according to claim 4, wherein, in the formation of
the open cell foam layer, an open cell foam layer with a desired
thickness is formed by controlling the concentration of silicone
solution, the size of solid particles or powders, and organic
solvent treatment speed.
12. The method according to claim 4, wherein an open cell foam
layer with a desired thickness is formed by repeating the formation
of the open cell foam layer.
13. The method according to claim 4, wherein the formation of the
open cell foam layer further includes: removing nips
(post-processing) to control the thickness of the formed open cell
foam layer or to realize excellent appearance.
14. The method according to claim 4, wherein, in the formation of
the open cell foam layer, the treated solid particle or powder for
formation of the open cell is removed by directly or indirectly
treating the artificial breast shell provided with an open cell
with water vapor.
15. The method according to claim 4, wherein the formation of the
open cell foam layer further includes: a drying and curing
operation of drying and curing the formed open cell foam layer.
16. The method according to claim 15, wherein the drying is carried
out by completely evaporating the organic solvent at 30.degree. C.
in an oven and the curing is carried out by curing the silicone
solution present on the dried artificial breast mold in an oven at
170.degree. C. for three hours.
17. The method according to claim 15, further comprising: rubbing
treating the artificial breast shell provided with dried and cured
open cell foam layer to remove the solid particle or powder.
18. The method according to claim 15, further comprising: heating
and high-pressure vapor treating the artificial breast shell
provided with dried and cured open cell foam layer in the presence
of 140.degree. C. water and 1.4 atm vapor, for about 30 hours, to
remove the solid particle or powder.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of pending International Patent
Application PCT/KR2010/001826 filed on Apr. 12, 2010, which
designates the United States and claims priority of Korean Patent
Application No. 10-2009-0112022 filed on Nov. 19, 2009, the entire
contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to an artificial breast
implant, the surface of which is formed or modified with a silicone
open cell (open pore) foam layer, and a method for producing the
same. More specifically, the present invention relates to an
artificial breast implant that has an open cell foam layer made of
silicone on the surface thereof and thus minimizes side effects
such as in vivo rejection, which may occur after insertion of the
implant into the human body, in particular, the occurrence of
capsular contracture to achieve superior biocompatibility and
safety, and a method for producing the same.
BACKGROUND OF THE INVENTION
[0003] In general, artificial breast prostheses are used in
reconstructive plastic surgery for a breast when breast loss occurs
due to diseases or accidents and in cosmetic surgery for a
malformed breast. In terms of anatomy, artificial breast prostheses
are also used for the substitution of organs or tissues.
[0004] Artificial breast prostheses are products in which a filling
material, such as saline, hydro-gel, and silicone gel, is filled in
an envelope formed of silicone that is implantable to an organ
(hereinafter referred to as a "shell"). These artificial breast
prostheses may be classified into round products and water drop
shaped products according to the shape of a product, and may be
classified into smooth products and textured products according to
the surface conditions of a product. More particularly, the
artificial breast prostheses will be described in brief as
follows.
[0005] A saline filled artificial breast prosthesis is configured
such that saline is injected or is injectable into a shell formed
of silicone (more particularly, the shell being formed of
polyorganosiloxane, such as polydimethylsiloxane or
polydiphenylsiloxane). The saline filled artificial breast
prosthesis has a structure consisting of a silicone shell and a
valve.
[0006] Although the saline filled artificial breast prosthesis
ensures safety of a user even if the filling material leaks into
the human body after rupture of the shell as a result of using
sterile saline as the filling material, and is easy to change the
volume of a breast by adjusting the injection amount of saline, the
saline filled artificial breast prosthesis is significantly
deteriorated to the touch after surgery as compared to other
artificial breast prostheses and the shell thereof has inferior
durability.
[0007] A hydro-gel filled artificial breast prosthesis is
configured such that hydro-gel composed of monosaccharide and
polysaccharides is filled within the same shell as that used in the
above described saline filled artificial breast prosthesis. The
hydro-gel filled artificial breast prosthesis is a product
developed based on the principle that the filling material can be
absorbed into and excreted from the human body even if the filling
material leaks into the human body due to rupture of the shell.
[0008] However, in the case of the hydro-gel filled artificial
breast prosthesis, safety with respect to long term use has not
been established, volume change depending on the lapse of time and
occurrence of wrinkles may increase after the artificial breast
prosthesis is inserted into the human body, and feeling is
unnatural as compared to a silicone gel filled artificial breast
prosthesis. At present, the above described hydro-gel filled
artificial breast prostheses are not distributed on the market on
the basis of the year 2000 due to problems in relation to the proof
of safety.
[0009] A silicone gel filled artificial breast prosthesis is
configured such that silicon gel having an appropriate viscosity is
filled in a shell. The silicone gel filled artificial breast
prosthesis has very superior product durability and more pleasant
texture than the saline filled artificial breast prosthesis, and
owing to these advantages, has achieved a dominant position in the
market.
[0010] The silicone gel filled artificial breast prosthesis has
been developed in the order of a first generation prosthesis, a
second generation prosthesis, and a third generation prosthesis.
This development history will be described in detail as
follows.
[0011] The first generation silicone gel filled artificial breast
prosthesis is a product sold from the middle of the 1960s to the
middle of the 1970s, and was initially developed in the year 1961
by Cronin and Gerow. The first generation silicone gel filled
artificial breast prosthesis can be represented in brief by use of
a thick shell, a smooth surface type, and silicon gel of a high
viscosity. This prosthesis has caused gel bleed and capsular
contracture, but a rupture speed thereof was relatively low due to
the use of the thick shell.
[0012] The second generation silicone gel filled artificial breast
prosthesis is a product sold from the middle of the 1970s to the
middle of the 1980s, and includes a thin shell and a silicon gel
filling material of a low viscosity, for the sake of smoother
texture. This prosthesis is characterized by a similar gel bleed
rate, higher rupture occurrence, and lower capsular contracture as
compared to the first generation prosthesis.
[0013] The third generation silicone gel filled artificial breast
prosthesis is a product sold from the middle of the 1980s to
present, and includes a gel bleed barrier layer to prevent gel
bleed. The third generation silicone gel filled artificial breast
prosthesis includes a thicker shell and silicon gel of a higher
viscosity as compared to the second generation prosthesis. In
addition, a product having a rough surface has been developed, in
order to reduce capsular contracture. The third generation silicone
gel filled artificial breast prosthesis exhibit low rupture and low
capsular contracture occurrence, as compared to the first and
second silicone gel filled artificial breast prostheses.
[0014] As defined above, development and progress in terms of
artificial breast prosthesis safety have focused on decrease in
rupture and capsular contracture. This is a natural result, when
taking into consideration the fact that rupture and capsular
contracture are the greatest side effects of artificial breast
prostheses.
[0015] These two side effects, that is, rupture and capsular
contracture will be described. First, in the case of rupture, an
event in which Dow Corning sold the prosthesis was bankrupted due
to rupture of a great amount of the second generation silicone gel
filled artificial breast prosthesis using a thin shell is
well-known. The filling material (silicone gel) of the artificial
breast prosthesis may leak into the body through the ruptured
shell, deformation and malfunction of the prosthesis thus occur,
and, as a result, the prosthesis is removed.
[0016] Second, capsular contracture is a natural biological
rejection reaction in which collagen films are firmly accumulated
around a prosthesis, after insertion of the implant into the human
body, which is observed in all patients that undergo artificial
breast prosthesis surgery, but there is a difference in severity of
capsular contracture therebetween. Prostheses are removed from
patients that suffer from serious capsular contracture.
[0017] Considering prosthesis removal operation caused by side
effects according to various causes, capsular contracture is known
to be the most significant side effect of artificial breast
prostheses, which is demonstrated from various clinical papers
published for a long time.
[0018] In accordance with continuous research and progress of
artificial breast prostheses, for capsular contracture which is a
side effect having high onset and high re-operation, prostheses
capable of reducing the onset and reoperation is developed. As a
result, the third generation artificial breast prostheses have
emerged, and textured surface artificial breast implants in which
the surface thereof is roughly formed or modified in order to
reduce capsular contracture were developed and distributed in the
market.
[0019] Such a textured artificial breast implant minimizes
hardening of collagen films deposited on the surface thereof, thus
minimizing occurrence of capsular contracture. Various methods to
form a rough surface of an artificial breast implant have been
developed to date. However, methods having commercial availability
are classified into four forms, that is, urethane foam, solid
particle, processed mold, and pressed mold forms.
[0020] Of these, artificial breast implants in which urethane foams
developed by methods described in U.S. Pat. No. 3,366,975 and U.S.
Pat. No. 3,683,424 formed on the surfaces thereof are known to
exhibit the greatest effects on reduction of capsular contracture,
but such a method and product are not used at present due to the
problem associated with safety of urethane in the body.
[0021] U.S. Pat. No. 4,889,744, U.S. Pat. No. 5,545,220, and U.S.
Pat. No. 5,964,803 disclose methods for forming artificial breast
implants having a textured (rough) surface, by adhering solid
particles to artificial breast shells, or adhering solid particles
to artificial breast shells, followed by melting.
[0022] U.S. Pat. No. 4,965,430 discloses a method for producing
artificial breast implants with a textured surface, by forming a
textured surface on a mold used for preparation of an artificial
breast implant.
[0023] U.S. Pat. No. 4,960,425, U.S. Pat. No. 4,955,909, U.S. Pat.
No. 5,022,942, and U.S. Pat. No. 5,236,453 disclose methods for
producing an artificial breast implant having a textured surface by
adhering a film surface-roughened through a mold or ion beam to an
artificial breast shell using a press mold.
[0024] Of these methods, except the method of forming a urethane
foam on the surface of an artificial breast, other methods simply
make the surface of the artificial breast rough and have lower
efficacy in terms of reduction of capsular contracture as compared
to urethane foam artificial breasts.
[0025] The reason for this is that except the method of forming a
urethane foam on the surface of the artificial breast, other
methods are low in uniform deposition and hardening prevention of
collagen films on the surface of implants, as compared to urethane
implants, since a textured surface form, more specifically,
textured mono-layer, not a foam layer, is formed on the surface of
the artificial breast.
[0026] As described above, the development and progress in terms of
safety of silicone artificial breast implants have focused on
decrease in rupture and capsular contracture, but methods developed
to date are not complete in technical regards, and in particular,
have a high capsular contracture onset as a side effect, thus
entailing considerably frequent removal and re-operation of the
implants. This fact is clinically demonstrated.
[0027] Accordingly, development of artificial breast implants that
are capable of reducing capsular contracture and exhibit superior
durability remains as a problem that should be urgently and
completely solved.
SUMMARY OF THE INVENTION
[0028] The present invention has been made in view of the above
problems of the related art, and it is one object of the present
invention to provide an artificial breast implant that minimizes
capsular contracture, which may occur after insertion of the
implant into the human body, and thus achieves superior
biocompatibility and safety.
[0029] It is another object of the present invention to provide an
artificial breast implant that minimizes occurrence of capsular
contracture and exhibits superior durability.
[0030] To solve the above described technical objects and in
accordance with one embodiment of the present invention, an
artificial breast implant of the present invention is characterized
in that a silicone open cell (open pore) foam layer is formed or
modified on the surface of an implant shell with a uniform
thickness.
[0031] According to the present invention, the artificial breast
implant includes a silicone open cell foam layer on the surface
thereof, thus minimizing a side effect such as capsular
contracture, which may occur after insertion of the implant into
the human body. In addition, the artificial breast implant includes
a silicone foam layer with a uniform thickness present on the
silicone shell, thus preventing occurrence of stress concentration,
and exhibiting superior durability, as compared to conventional
textured surface silicone artificial breast implants.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a cross-sectional view illustrating the structure
of a conventional textured surface silicone artificial breast
implant;
[0033] FIG. 2 is a cross-sectional view illustrating the structure
of a conventional textured surface silicone artificial breast
implant;
[0034] FIG. 3 is a cross-sectional view illustrating the structure
of a conventional textured surface silicone artificial breast
implant;
[0035] FIG. 4 is a surface microscope image illustrating a
conventional textured surface silicone artificial breast
implant;
[0036] FIG. 5 is a cross-sectional surface microscope image
illustrating a conventional textured surface silicone artificial
breast implant;
[0037] FIG. 6 is a surface electron microscope image illustrating a
conventional urethane-coated silicone artificial breast
implant;
[0038] FIG. 7 is a cross-sectional view illustrating a silicone
artificial breast implant provided with a silicone open cell foam
according to the present invention;
[0039] FIG. 8 is a surface microscope image illustrating a silicone
artificial breast implant provided with a silicone open cell foam
according to the present invention;
[0040] FIG. 9 is a surface image illustrating a silicone artificial
breast implant provided with a silicone open cell foam according to
the present invention;
[0041] FIG. 10 is a surface image illustrating a silicone
artificial breast implant provided with a silicone open cell foam
according to the present invention; and
[0042] FIG. 11 is a block diagram illustrating a method for
producing a silicone artificial breast implant provided with a
silicone open cell foam according to one embodiment of the present
invention.
DESCRIPTION OF REFERENCE NUMERALS OF IMPORTANT PARTS OF THE
DRAWINGS
[0043] 10: silicone Shell 20, 30, 40: protrusion 50: pore, cell
[0044] 60: silicone open cell foam 70: silicone open cell foam
layer.
DETAILED DESCRIPTION OF THE INVENTION
[0045] The artificial breast implant of the present invention is
characterized in that the artificial breast implant is provided on
the surface thereof with a silicone open cell foam layer, wherein
the silicone open cell foam layer with a uniform thickness is
disposed on a silicone shell with a uniform thickness.
[0046] Hereinafter, the present invention will be described in
detail with reference to the annexed drawings.
[0047] FIGS. 1, 2 and 3 are cross-sectional views illustrating the
structure of a conventional textured surface silicone artificial
breast implant.
[0048] Specifically, FIG. 1 shows a textured surface silicone
artificial breast implant which is produced by etching a sheet 10
provided with a protrusion 20 to the surface of an artificial
breast implant using a press mold or by etching the surface of the
implant using an ion-beam thruster, and the surface thereof has a
very simple structure, as compared to the surface of the textured
surface silicone artificial breast implant surface, produced by
another method. Accordingly, a textured surface implant to reduce
capsular contracture has lower efficacy than other textured surface
implants.
[0049] FIG. 2 shows a textured surface implant that is produced by
etching the surface thereof using a solid particle, has a
complicated surface structure, and a dense protrusion structure, as
compared to the surface of implant of FIG. 1. However, this implant
also has a limitation in that the protrusion 40 of the surface is
in the form of a monolayer surface, not a foam, as shown in the
drawing, has a non-uniform shell thickness and thus entails
occurrence of stress concentration due to presence of protrusions
40 and 50, thus causing a deterioration in durability of shells,
that is, implants.
[0050] FIG. 3 shows a textured surface implant that is produced by
adhering a solid particle or using an etched mold. This implant
also has a relatively simple surface structure, has a shell 10 with
a considerably non-uniform thickness, as shown from thickness
difference between surfaces a and b, and has an implant durability
problem due to stress concentration.
[0051] FIG. 4 is a surface microscope image illustrating a
conventional textured surface silicone artificial breast implant.
From FIG. 4, it can be seen that the implant is provided on the
surface thereof with monolayer-shaped regular or irregular
protrusions. FIG. 5 is a cross-section surface microscope image of
a conventional textured surface silicone artificial breast implant.
From FIG. 5, it can be seen that the shell has a non-uniform
thickness and has cracks, which may be a break point, present in
the center of the shell.
[0052] FIG. 6 is a surface electron microscope image illustrating a
conventional urethane-coated foam-type silicone artificial breast
implant. From FIG. 6, it can be seen that a cell has a complicated
three-dimensional net structure.
[0053] As described above, such conventional textured surface
artificial breast implants are ineffective for reducing capsular
contracture, have low durability, or have a safety problem, such as
urethane-coated implants.
[0054] However, as shown in FIG. 7, the artificial breast implant
of the present invention has a characteristic configuration in
which a silicone open cell foam layer 70 with a uniform thickness
is disposed on a silicone shell 10 with a uniform thickness, and
all components of the artificial breast implant of the present
invention are made of polyorganosiloxane.
[0055] The polyorganosiloxane used for the artificial breast
implant uses the following materials as materials having an implant
grade capable of securing safety after implantation into the human
body.
[0056] Basically, polyorganosiloxane has a structure in which a
main chain is silane, and an organic group such as a methyl group
is bonded to the silane main chain.
[0057] The most representative example is polydimethylsiloxane in
which a methyl group is bonded to the main chain. The methyl group
of dimethylsiloxane which is a monomer of polydimethylsiloxane may
be substituted by an organic group such as alkyl group, phenyl
group, or vinyl group.
[0058] For example, the dimethylsiloxane is substituted by methyl
hydrogen siloxane, methyl phenyl siloxane, diphenyl siloxane,
dimethyl vinyl siloxane, tri-fluoropropyl siloxane or the like, and
polymers can be prepared by polymerization of these monomers and
used. Also, copolymers using oligomers comprising these monomers
can be produced and used.
[0059] FIG. 8 is a surface microscope image illustrating a silicone
artificial breast implant provided with a silicone open cell foam.
An open cell 50 of FIG. 7 has a three-dimensional net structure.
FIG. 9 is a surface image illustrating a silicone artificial breast
implant provided with a silicone open cell foam, which shows a
state in which a foam layer with a considerably thin thickness
(mean height: 300 um) is formed. FIG. 10 is a surface image
illustrating a silicone artificial breast implant provided with a
silicone open cell foam, which shows a state in which a foam layer
with a suitable thickness (mean height: 1,500 um) is formed.
[0060] The silicone open cell foam layer formed on the surface of
the implant according to the present invention prevents hardening
of collagen films deposited around the implant after insertion into
the human body and thus prevents occurrence of capsular
contracture. In addition, although collagen films are deposited
around the implant, collagen is grown in the open cell foam layer
formed on the implant and a sponge-like structure is formed, not a
hard plate-shaped structure.
[0061] Accordingly, collagen tissues having an elasticity similar
to other human body tissues are formed and occurrence of capsular
contracture can thus be minimized. Furthermore, after insertion of
an implant into the human body, the implant is rapidly fixed on the
operation site due to in-growth of collagen in the implant and
recovery of patients can be also facilitated.
[0062] Meanwhile, the artificial breast implant provided with a
silicone open cell foam layer according to the present invention is
produced by a method including:
[0063] a silicone dipping operation of dipping a breast-shaped mold
in a silicone solution to obtain an artificial breast shell
(S100);
[0064] a drying and curing operation of drying an artificial breast
shell adhered to the mold using a drier, followed by curing, to
obtain a silicone artificial breast shell (S200);
[0065] an open cell formation operation of forming an open cell
foam layer on the surface of the dried and cured shell (S300);
[0066] an artificial breast shell acquisition operation of forming
an aperture on the bottom of the artificial breast shell adhered to
the mold and provided with the open cell foam layer and removing
the artificial breast shell from the mold (S400); and
[0067] an implant formation operation of adhering a silicone film
including a leakage prevention film to the aperture to fill the
aperture (S500).
[0068] Hereinafter, a method for producing an artificial breast
implant provided with the silicone open cell foam layer according
to the present invention will be described in more detail.
[0069] First, a breast-shaped mold is treated with a silicone
solution by dipping or the like, to obtain an artificial breast
shell (S100)
[0070] The mold is taken out in the silicone solution, dried and
cured to obtain a silicone artificial breast shell. For example,
the artificial breast shell is dried in a drier such as an oven and
cured (S200).
[0071] An open cell foam layer is formed on the dried and cured
artificial breast shell (S300).
[0072] More specifically, the formation of the open cell foam layer
is carried out by dipping the dried and cured mold provided with
the shell in a silicone solution to form a silicone solution film
on the surface of the shell, and treating the surface of the shell
by scattering or spraying, to the surface of the shell, a solid
particle or powder with an appropriate size such that the silicone
solution film loses its flowability.
[0073] At this time, the solid particle or powder is not affected
by the silicone solution and is not dissolved. In addition, the
solid particle or powder that does not affect physical properties
of silicone which contacts the solid particle or powder is used. In
addition, the solid particle or powder is dissolved and thus
removed by an appropriate solvent in the following process. The
most preferred solvent is water.
[0074] When water is used as a solvent to remove the solid particle
or powder, sodium chloride, ammonium carbonate, ammonium phosphate,
ammonium chloride or the like may be used. Most preferred is sodium
chloride.
[0075] The shell whose surface is entirely stained with the
silicone solution and solid particle or powder, that is, the
shell-provided mold is treated with an organic solvent by spraying
or dipping. At this time, applicable organic solvents are readily
miscible with a silicone solution and are generally an aromatic
organic solvent or a derivative thereof such as benzene, toluene or
xylene, most preferably xylene.
[0076] The organic solvent-treated shell is treated with a solid
particle or powder. The solid powder or particle used herein is
completely dried. Through this process, the treated solid particle
or powder is soaked by the silicone solution by capillary
action.
[0077] At this time, an open cell foam layer with desired thickness
can be formed by controlling and repeating the concentration of the
silicone solution, size of solid particle or powder, and organic
solvent treatment speed. In addition, the thickness of the open
cell foam layer can be controlled by post-processing using a
nap-removing apparatus.
[0078] Next, after formation of the open cell foam layer, the open
cell foam layer is dried and cured. After completion of curing, the
open cell foam layer is treated with a solvent such as water to
remove the solid particle or powder. At this time, the open cell
foam layer may be rubbed by an apparatus causing no nipping such as
soft cloth or a brush.
[0079] In the process of rubbing, a small amount of close cell
which is inevitably produced during formation of foams can be
partially removed. The reason for this is that the cell wall of
foams is considerably thin. In the process of rubbing, solid
particles or powders that are not dissolved in a small amount of
close cells and remain are rubbed together via considerably thin
cell walls, thus producing apertures on the cell walls.
[0080] At this time, the solid particles or powders that are not
removed by the rubbing process can be completely removed by
repeating permeation of high-pressure water vapor and washing. This
process is carried out by extraction-removing solid particles or
powders that are not removed and remain, through permeation of
water vapor and uses a property in that silicone permeates water
vapor. That is, solid particles or powders dissolved in water vapor
are changed into those having a small enough size that they can
pass through silicone molecules and are then extracted outside, and
can be thus completely removed by repeated extraction and washing
operations.
[0081] Such water vapor treatment includes direct water vapor
treatment in which artificial breast shells are directly treated
with water vapor and indirect water vapor treatment in which
artificial breast shells are boiled in a container containing
water.
[0082] In accordance with the formation method of the open cell
foam layer according to the present invention, a foam layer is
formed using solid particles or powders and organic solvent by
capillary action, while forming a foam layer on the cured shell
surface. As shown in FIG. 7, the thickness of the uniform shell can
be maintained and stress concentration caused by non-uniform shell
thickness can be prevented, and shell and implants with superior
durability can be obtained.
[0083] An aperture is formed on the bottom of the artificial breast
shell provided with the open cell foam layer and adhered to the
mold, and the artificial breast shell is detached from the mold to
obtain an artificial breast shell (S400).
[0084] Silicone fragments having a similar size to the aperture 128
are adhered to the aperture to fill the aperture and thereby an
implant (S500). At this time, adhering of silicone fragments can be
carried out by press molding or using a bonding material or the
like. This will be easily understood by those skilled in the art of
artificial breast implants and a detailed explanation thereof is
thus omitted.
[0085] Also, all of the contents that are not described in detail
in the production method are easily understood by those skilled in
the art of producing artificial breast implants and a detailed
explanation thereof is thus omitted.
Example 1
[0086] First, methyl hydrogen siloxane; dimethylsiloxane containing
a small amount of platinum catalyst, containing about 20% of a
silica filler and having a molecular weight of 50,000 to 100,000
ten thousands; and dimethyl vinyl siloxane containing dimethylvinyl
terminated siloxane having a dimethyl group as a terminal group,
containing 20% of a silica filler and having a molecular weight of
50,000 to 100,000 ten thousands were sufficiently mixed at an
equivalent ratio of methyl hydrogen siloxane to prepare a silicone
material.
[0087] Xylene as an organic solvent was added to the silicone
material silicone such that the concentration of the silicone was
35 wt %, followed by thoroughly mixing to prepare a silicone dilute
solution.
[0088] Then, a breast-shaped mold for artificial breast shell was
treated and coated with the silicone dilute solution by dipping,
the organic solvent was completely evaporated at 50.degree. C. in
an oven, the mold was dried, and the dried artificial breast mold
provided with a silicone coating film was cured in an oven at
170.degree. C. for three hours.
[0089] The artificial breast mold provided with a dried silicone
coating film was sufficiently cooled at room temperature and
treated by dipping in the 35 wt % silicone dilute solution.
[0090] Then, the dilute silicone solution-coated artificial breast
mold was treated with dried sodium chloride (NaCl) with an average
particle size of 500 um by spraying, and an artificial breast mold
treated with the silicone dilute solution and sodium chloride was
treated with xylene by dipping.
[0091] Then, the xylene-treated artificial breast mold was treated
with dried sodium chloride (NaCl) with an average particle size of
500 um by spraying, the artificial breast mold treated with sodium
chloride was treated with xylene by dipping, and the organic
solvent was completely evaporated at 30.degree. C. in an oven,
followed by drying.
[0092] Then, the xylene-treated artificial breast mold was treated
with dried sodium chloride (NaCl) with an average particle size of
200 um by spraying, the artificial breast mold treated with sodium
chloride was treated with xylene by dipping, and the organic
solvent was completely evaporated at 30.degree. C. in an oven,
followed by drying.
[0093] Silicone formed on the dried artificial breast mold was
completely cured at 170.degree. C. in an oven for three hours, and
the cured artificial breast shell formed on the artificial breast
mold was rubbed with a brush in room temperature clear water to
remove sodium chloride.
[0094] Then, the silicone foam formed on the artificial breast
shell surface was processed to a uniform thickness using a
nip-removal apparatus to realize excellent appearance and even
surface. At this time, the height of foam layer can be post-treated
to a desired thickness by the method.
[0095] Then, the artificial breast shell was washed with IPA and
water in order to remove foreign materials, an aperture was formed
on the bottom of the silicone shell of the artificial breast mold,
and the silicone shell was detached from the mold and obtained.
[0096] Then, to remove incompletely removed sodium chloride, the
artificial breast shell was heated in the presence of 140.degree.
C. water and 1.4 atm vapor using a high-pressure vapor sterilizer
for about 30 hours and the treated artificial breast shell was
alternately washed with clear water and IPA.
[0097] The high-pressure vapor treatment and washing operations
were repeated five times, to obtain a silicone shell provided on
the surface thereof with a sodium chloride-completely removed open
cell foam layer. An aperture present on the bottom of the silicone
shell provided on the surface thereof with the open cell foam layer
was adhered and sealed to form an implant shell. The implant-formed
shell was filled with silicone gel as a filler using a filling
apparatus and cured to produce a silicone artificial breast
implant.
[0098] Those skilled in the art will appreciate that the above
description can be implemented in other detailed embodiments
without changing technical ideas or essential characteristics of
the present invention. Therefore, it should be understood that the
above described embodiments are given only by way of example and
the present invention is not limited thereto.
[0099] Accordingly, the scope of the present invention is defined
by the accompanying claims other than the above detailed
description, and all modifications or alternatives deduced from the
spirit and scope of the invention as defined by the claims and
equivalent concepts thereof should be construed as being included
in the scope of the present invention.
* * * * *