U.S. patent application number 14/503953 was filed with the patent office on 2016-04-07 for engineered leather for airbag, steering wheel, and seatbelt applications.
The applicant listed for this patent is Autoliv ASP, Inc.. Invention is credited to Conrad C. Dumbrique, Uriel P. Hernandez, Chandrakanth Siddharthan, Adam T. Vile.
Application Number | 20160097154 14/503953 |
Document ID | / |
Family ID | 55631231 |
Filed Date | 2016-04-07 |
United States Patent
Application |
20160097154 |
Kind Code |
A1 |
Dumbrique; Conrad C. ; et
al. |
April 7, 2016 |
ENGINEERED LEATHER FOR AIRBAG, STEERING WHEEL, AND SEATBELT
APPLICATIONS
Abstract
Methods of covering portions of an automobile interior with an
engineered leather are provided. When a mold of the appropriate
shape is provided, a cell paste can be placed therein and grown
into a leather, which can be tanned and treated to produce a
suitable covering for a portion of an automobile interior, such as
a steering wheel, an airbag cover, or a seat belt assembly. A
method of growing a seamless automobile component cover in situ is
disclosed.
Inventors: |
Dumbrique; Conrad C.; (Lake
Orion, MI) ; Vile; Adam T.; (Fenton, MI) ;
Siddharthan; Chandrakanth; (Troy, MI) ; Hernandez;
Uriel P.; (Lake Orion, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Autoliv ASP, Inc. |
Ogden |
UT |
US |
|
|
Family ID: |
55631231 |
Appl. No.: |
14/503953 |
Filed: |
October 1, 2014 |
Current U.S.
Class: |
435/395 ; 428/80;
435/325 |
Current CPC
Class: |
B62D 1/06 20130101; D06N
3/00 20130101; C08G 2101/00 20130101 |
International
Class: |
D06N 3/00 20060101
D06N003/00 |
Claims
1. A covering for an article, the article having an outer surface,
the covering comprising at least one layer of at least one type of
engineered leather, the engineered leather having been cultured on
a surface of a preconstructed mold, the mold having similar
dimensions to the article to be covered.
2. The covering of claim 1 wherein the mold has an top portion and
a bottom portion, a cell growth space being defined between the top
portion and the bottom portion, the engineered leather being
cultured in the cell growth space and being preshaped therein.
3. The covering of claim 2 wherein the article is a portion of an
automobile interior.
4. The covering of claim 3 wherein the article comprises a steering
wheel.
5. The covering of claim 3 wherein the article comprises an airbag
cover.
6. The covering of claim 3 wherein the article comprises a portion
of a safety belt assembly.
7. The covering of claim 6 wherein the article comprises a buckle
assembly of a safety belt assembly.
8. The covering of claim 1 wherein the covering comprises two or
more types of engineered leather.
9. The covering of claim 1 wherein the covering undergoes a tanning
process.
10. A method of covering an article with at least one layer of at
least one type of engineered leather comprising the steps of:
providing a mold having a top portion and a bottom portion;
providing a cell aggregate and placing the cell aggregate on the
bottom portion of the mold; providing a quantity of tissue culture
medium to the cell aggregate; placing the top portion of the mold
over the cell aggregate; placing the mold in a chamber adapted to
allow for cell growth; allowing the cells to grow until they form
an engineered leather within the mold; and processing the leather
to form a covering for an article.
11. The method of claim 10 wherein the cell aggregate comprises
epithelial cells.
12. The method of claim 10 wherein the cell aggregate comprises a
cell paste.
13. The method of claim 10 wherein the cell aggregate comprises at
least one elongated sheet of cells.
14. The method of claim 10 wherein collagen is exogenously supplied
to the cell aggregate.
15. The method of claim 13 comprising a plurality of elongate
sheets of cells comprising a first sheet of cells and a second
sheet of cells, the second sheet of cells being posited over the
first sheet of cells, a layer of collagen being provided between
the first sheet of cells and the second sheet of cells.
16. The method of claim 10 wherein the cell aggregate is formed
from a skin punch from at least one donor animal.
17. The method of claim 10 wherein the processing step comprises
tanning.
18. A method of forming a preshaped engineered leather for covering
an article with at least one layer of at least one type of
engineered leather comprising the steps of: providing an article
having an outer surface; providing a mold having an inner surface
for growing cells; providing a cell aggregate and placing the cell
aggregate on the inner surface of the mold and on the outer surface
of the article; providing a quantity of tissue culture medium to
the cell aggregate; placing the article in a chamber adapted to
allow for cell growth; allowing the cells to grow until they form
an engineered leather within the mold and on the surface of the
article; and removing the mold.
19. The method of claim 18 wherein the preshaped engineered leather
defines a seamless covering for the article.
20. An engineered leather having a portion which is cylindrical in
shape formed by the steps of placing a cell paste on a cell-growth
surface of a substantially cylindrical mold, placing the mold in an
incubator, permitting cell growth until a substantially cylindrical
leather is formed, removing the substantially cylindrical leather
from the mold, and treating the leather.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to finishes and methods of
coating objects. More particularly, it relates to the use of
cultured or engineered leather to cover surfaces of automobile
components. Even more particularly, the present invention relates
to coverings for automotive components such as steering wheel
armatures, air bags, safety belt parts, door panels, and other
surfaces made from one or more layers of laboratory-grown,
cultured, or engineered leather, which have been grown inside of a
mold constructed in the proper dimensions for production of said
coverings.
BACKGROUND
[0002] Leather has been used in a great variety of luxury and
durable goods. One notable use of leather has been in the trim of
automobiles, particularly as seat and steering wheel coverings.
However, there are disadvantages to using leather. For instance,
the hide of an animal must be acquired, treated, cut, and sewn to
the appropriate size and shape. Animals such as cattle which are
raised for this purpose require great amounts of feed and space,
and raising them can be relatively expensive. The treatment of
leather can be a lengthy process and can also involve the use of
toxic compounds, such as chrome salts. Because the leather must be
shaped and cut to fit the component it is to cover, scraps are
produced and discarded. Finally, the thickness and toughness of the
leather can make it difficult to create predictable seams with a
good fit during the fixation step to the surface.
[0003] Materials have been developed to function as artificial
leathers, but these generally consist of a base layer of fabric
covered with a plastic. As such, these artificial leathers lack the
tactile characteristics and the durability of genuine leather and
can be perceived as unsuitable even for decorative use by
consumers.
[0004] Therefore, a way of preshaping a piece of leather such that
minimal or no sewing is required to attach the leather to an
article to be covered would be advantageous. Moreover, a leather
that would not need to be cut or derived from the intact skin of a
donor animal would aid in cost savings and efficiency.
BRIEF SUMMARY
[0005] In a first embodiment, the invention provides a covering for
an article having an outer surface, the covering having at least
one layer of at least one type of engineered leather, the
engineered leather having been cultured in a mold. The mold has a
bottom portion and a top portion, a cell growth space being defined
between the bottom portion and the top portion. In particular, the
article may be a component of an automobile interior.
[0006] In another embodiment, the invention provides a method of
covering an article with at least one layer of at least one type of
engineered leather. In a first step, a mold with a top portion and
a bottom portion is provided. In a second step, a cell aggregate is
provided and placed on the bottom portion of the mold. In a third
step, a quantity of tissue culture medium is provided to the cell
aggregate. In a fourth step, the top portion of the mold is placed
over the cell aggregate. In a fifth step, the article is placed in
a chamber adapted to allow for cell growth. In a sixth step, the
cells are allowed to grow until they form an engineered leather
within the mold. Finally, in a seventh step, the mold is removed to
form a covering for the article.
[0007] In another embodiment, a method of forming a preshaped
engineered leather for covering an article with at least one layer
of at least one type of engineered leather is provided. In a first
step, an article having an outer surface is provided. In a second
step, a mold having an inner surface for growing cells is provided.
In a third step, a cell aggregate is provided and placed on the
inner surface of the mold. In a fourth step, a quantity of tissue
culture medium is provided to the cell aggregate. In a fifth step,
the article is placed in a chamber adapted to allow for cell
growth. In a sixth step, the cells are allowed to grow until they
form an engineered leather within the mold. Finally, the mold is
removed to form a covering for the article.
[0008] In a further embodiment, the invention is characterized by
an engineered leather having a substantially cylindrical shape
formed by the steps of placing a cell paste on a cell-growth
surface of a substantially cylindrical mold, placing the mold in an
incubator, permitting cell growth until a substantially cylindrical
leather is formed, removing the substantially cylindrical leather
from the mold, and treating the leather.
[0009] Further objects, features, and advantages of the present
invention will become apparent from consideration of the following
description and the appended claims when taken in connection with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a flowchart illustrating steps of one method of
covering an article in a layer of engineered leather in accordance
with one embodiment of the present invention;
[0011] FIG. 2 is an illustration of steps involved in covering a
steering wheel in a layer of engineered leather in accordance with
one embodiment of the present invention;
[0012] FIG. 3 is an illustration of a process wherein leather is
cultured within a mold to cover a steering wheel in accordance with
embodiments of the present invention;
[0013] FIG. 4A is a perspective view of a steering wheel which has
a heating element and an engineered leather cover in accordance
with another embodiment of the present invention;
[0014] FIG. 4B is a perspective view of a steering wheel armature
having a selective leather finish in accordance with another
embodiment of the present invention;
[0015] FIG. 5A is a cross-sectional schematic view of the
arrangement of layers of a prior art steering wheel armature;
[0016] FIG. 5B-5C are cross-sectional schematic views of the
arrangement of layers of steering wheel armatures in accordance
with embodiments of the present invention;
[0017] FIG. 6 is a schematic cross-sectional view of a steering
wheel armature which is adapted to be coated by leather culturing
in situ;
[0018] FIG. 7A-7C are illustrations of other automotive components
which are amenable to the growth of engineered leather in situ in
accordance with further embodiments of the present invention;
and
[0019] FIG. 8A-8C are perspective views of a variety of molds for
culturing a preshaped engineered leather in accordance with another
embodiment of the present invention.
DETAILED DESCRIPTION OF THE DRAWINGS AND THE PRESENTLY PREFERRED
EMBODIMENTS
[0020] The description that follows is not intended to limit the
scope of the invention in any manner, but rather serves to enable
those skilled in the art to make and use the invention.
[0021] It is to be understood that the figures are schematic and do
not show the various components to their actual scale. In many
instances, the figures show scaled up components to assist the
reader.
[0022] The terms "substantially" or "about" used herein with
reference to a quantity includes variations in the recited quantity
that are equivalent to the quantity recited, such as an amount that
is equivalent to the quantity recited for an intended purpose or
function.
[0023] The terms "engineered leather," "cultured leather,"
"lab-grown leather," and "laboratory-created leather" are used
interchangeably herein to refer to a leather product which, at
least in part, is grown in vitro or not directly harvested from a
host animal.
[0024] Although cultured, engineered, or lab-grown leathers have
been proposed, to date these have involved creation of sheets of
leather which still need to be finished, cut, and sewn in order to
be incorporated into a final product. In contrast, the present
invention provides an engineered leather that has been grown in a
mold into substantially its final shape in order to minimize waste
and processing time and costs.
[0025] Leather receives its characteristic look and toughness from
the layers of animal skin from which it is made. The outermost
layer of skin of a mammal is the epidermis, which lies above a
basement membrane that separates it from the dermis or corium. The
epidermis is made up generally of keratinocytes.
[0026] The basement membrane is a network of proteins that forms a
portion of the extracellular matrix (ECM.) In the case of skin, the
ECM is made up largely of collagens, though other fibrous proteins
and glycosaminoglycans and other types of protein are also present.
Collagen is secreted by collagen-secreting cells. Present within
the matrix can also be fibroblasts, which among other things
secrete elastins, proteins which give elasticity to the skin
tissue, in contrast to the strength and structure imparted by
collagen. The dermis is linked to the epidermis by this
extracellular matrix.
[0027] Collagens are important proteins not only because of their
abundance and their structural properties which keep the skin
intact in a living animal, but because the leather tanning process
chemically alters the structure of the collagen component of a skin
that is treated. In general, more collagen makes for a stronger
leather. For that reason, the use of collagen as an additive to
increase the strength of a cultured leather is considered in view
of the present invention.
[0028] The engineered leather should be hairless and as free from
blood vessels and other such disruptive physiological structures as
possible. This can be achieved either by selecting for progenitor
leather samples to expand or by making advantageous genetic
mutations in a leather sample using known molecular biology or
nucleic acid manipulation techniques. Such modifications could be
made to target genes to, for example, accelerate proliferation,
prevent follicle formation, minimize vascularization, and so
forth.
[0029] Turning now to the cells to be used, these can be from a
variety of sources and presented in a variety of formats. In one
instance, the primary source of the skin cells can be a skin punch
from a mammal, such as cattle. Because of the potency of in vitro
tissue culture techniques, a small punch (about 1 cm in diameter)
can be sufficient to grow an indefinitely large number of cells if
handled properly. The cells from such a skin punch can be expanded
and eventually form the basis for a cell aggregate such as a cell
paste for leather formation.
[0030] After the precursor cells have been obtained and, if the
initial quantity was insufficient, expanded, a cell paste or cell
aggregate can be made. This can be achieved by mixing cells or cell
aggregates (of one or more cell types) and a cell culture medium,
preferably in a pre-determined ratio, to create a cell suspension.
Alternatively, if cells have been obtained and grown in suspension,
they can be concentrated to achieve the desired cell concentration
(density), viscosity, and consistency required for the cell paste.
In some embodiments, compounds or artificial matrices are combined
with the cell suspension to enhance the physical characteristics of
the cell paste. These additives can include for example collagen,
hydrogels, MATRIGEL, and the like. A cell paste may have a
generally amorphous or unorganized structure, or may comprise an
aggregate having a specific shape, such as a sphere, an elongated
strip, or any other shape.
[0031] In one embodiment, the cell paste can be placed onto a
surface or into a mold as-is. In another embodiment, a structured
multicellular body can be further fabricated from the cell paste.
The cell paste can be shaped into a desired shape, including but
not limited to a sphere, a sheet, a cylinder, or any other shape
necessary for practicing a particular application of the invention.
The cell paste can be placed in a controlled environment, such as
an incubator with a relatively high humidity level and carbon
dioxide provided, to allow the cells to adhere to one another or to
be distributed throughout the provided cell growth matrix to form
the desired shape.
[0032] Any type of incubator or bioreactor which is suitable for
cell growth may be chosen for the culturing of cells for an
engineered leather growth application in accordance with the
principles of the present invention. For instance, a conventional
bioreactor may be selected. Alternatively, a rotating bioreactor
having an outer casing or external sleeve which produces a varying
electromagnetic field to optimize cell growth may also be chosen.
In the latter case, the mold should be made of a material which
does not interfere with the electromagnetic field.
[0033] In one embodiment, the engineered leather can have an
initial culturing step wherein precursor sheets of cells are
arranged on a support which may optionally be biodegradable and
which permits the precursor sheets to grow together and form a
substantially cohesive and planar layer. In some embodiments, these
layers are arranged horizontally and/or vertically adjacent to one
another.
[0034] The matrix in which the cell paste is formed is
biocompatible and ideally biodegradable. That is, as the cells grow
and proliferate within the matrix or scaffold, the nutrients from
the tissue culture medium as well as the matrix itself can be
consumed by the cells and give way to a self-supporting skin
structure. Cells should be largely free of pores, fibrous tangles,
or other structure of the scaffold.
[0035] Tissue culture medium is supplied to the cultured cells.
Although the precise composition of the medium can be altered
according to the overall health of the cell population, a minimal
essential medium (MEM) which contains salts (such as calcium
chloride, sodium chloride, potassium chloride, sodium carbonate,
magnesium sulfate, and sodium phosphate), amino acids, vitamins
(such as calcium pantothenate, I-inositol, riboflavin, choline
chloride, nicotinamide, thiamine hydrochloride, folic acid, and
pyridoxal hydrochloride), and other components, particularly
D-glucose, sodium pyruvate, and lipoic acid, provides a basis for
the medium. Further to this, an enriching component such as a serum
may be included to create a rich medium. Acceptable enriching
components include but are not limited to horse serum, fetal bovine
serum, and human platelet lysate. Advantageously, a protein-rich
mixture which is low in antibodies and which can provide growth
factors may be selected. The medium should be buffered to a pH that
will keep the cell growth matrix intact and will allow for
proliferation of cells.
[0036] The tissue culture medium can be further supplemented with
substances that will aid in tissue growth and cultured leather
formation. Growth factors, hormones, and other molecules that
encourage cell proliferation in a general way can be included to
maintain or increase proliferation. ECM components such as collagen
can be provided exogenously in order increase the strength of the
intercellular protein scaffold. If genetic modifications including
the addition of selectable markers were made prior to culturing and
expansion in the incubator or bioreactor, a drug for selection
could be added. Molecules such as G418, zeocin, puromycin,
hygromycin B, and blasticidin can be provided in this manner,
dependent upon the genetic background of the particular cell
line.
[0037] In addition, antibiotics such as streptomycin and penicillin
can be added prophylactically in order to prevent growth of
microbes in the tissue culture media or cell growth scaffold.
[0038] Turning now to FIG. 1, a flowchart listing steps for
creating of an engineered leather inside of a mold is provided. In
a first step 10, a mold is provided, designed with the dimensions
of the object to be covered taken into account. In one embodiment,
the mold has dimensions, including a height, a width, a length, an
inner diameter, an outer diameter, or another dimension, that is
substantially equal to the size of the outer surface to be covered.
In another embodiment, the dimensions of the mold may be larger
than the object to be covered in any one or any combination of
dimensions. The mold may be about 5% larger, or about 10% larger,
or about 15% larger, or about 20% larger, or about 25% larger, or
between 0%-25% larger than the object to be covered in one
dimension or in any dimension to account for shrinkage of the
leather during treatment or formation of functional or decorative
elements in the leather, such as a seam. The mold can allow for
growth of a leather in substantially two dimensions, such as for a
planar covering of an article, or in three dimensions (length,
height, and width) which permits growth of a leather that has
substantially the same shape or a similar shape to a more
complex-shaped surface, such as a cylinder, a cone, a sphere, or a
combination of geometric solids.
[0039] In a second step 20, the cell paste is placed on a surface
of a mold. As mentioned before, the cell paste can be provided as a
series of substantially spherical particles, or as sheets, or as
layers, or as a substantially amorphous paste which is spread onto
the cell growth surface of the mold. The mold controls the shape
and extent of cell growth. In cases where a cell aggregate is
placed upon the article itself for expansion, the mold will define
the outer limit of cell growth and eventual leather formation.
[0040] The mold may be constructed of separate parts, such as a top
portion and a bottom portion that fit together in order to provide
a cell growth space there between. The top and bottom portions of
the mold may form a weak seal that is slightly permeable to air and
humidity within the incubator or bioreactor. Alternatively, the
mold may be of a single-piece construction, such as with a hinge
member, that closes upon itself to create a cell growth space on an
inner surface of the mold. Whether made of separate parts or as a
single piece, the portions of the mold that come together to
provide a cell growth surface may have different cavity profiles
from one or another, or the cavity profiles may be the same
throughout the parts of the mold.
[0041] The surface of the mold upon which cells grow should be
sterile and biocompatible, such that it will keep its shape when
cell paste, cell matrix or scaffold, and tissue culture medium are
added. In one embodiment, the surface of the mold is treated such
that it does not promote adhesion of the cells directly to it. In
another embodiment, the cells attach to the surface to some degree
during the culturing process, but are readily removed from the
surface (such as by adding trypsin) but the cells or layers of
cells remain cohered to one another and to the other layers of the
engineered layers.
[0042] To assist with initial adhesion of the cell paste, the cell
growth surface of the mold may be coated with a biocompatible and
easily removed or incorporated material such as agar or agarose.
Additionally or alternatively, the surface may be roughened or have
grooves formed thereupon in order to create surfaces amenable to
cell invasion and growth. A roughened surface also has the benefit
of producing a texture which has the same tactile qualities of
natural leather.
[0043] In a third step 30, the cells are cultured. The culturing
step may include placing the cells in an incubator or bioreactor
for at least about one night, or about one day, or about two days,
or about four days, or about one week, or about two weeks, or about
a month, or about two months, or about one day to about 60 days,
depending on the size of the article to be covered. During this
time the cells will ideally be monitored and checked every 24 hours
or about every 48 hours and appropriate media changes conducted.
Different supplements or even different types of tissue culture
media may be employed at various times in the culturing
process.
[0044] As the cells are cultured, the engineered leather forms by
fusion of cellular bodies which were initially separate from one
another. A collagen matrix forming between layers of cells can help
to give the nascent leather desirable strength and structural
properties. The collagen may be secreted by cells, such as
fibroblasts, and can also be provided at various times during the
culturing step to be incorporated by the growing leather bodies or
layers into an extracellular matrix. The ECM helps these leather
bodies to retain their shapes and to adhere to one another.
[0045] In an optional fourth step 40, the mold is removed. In a
case where the leather is likely to retain its three-dimensional
shape without the mold, such as a covering for a substantially
planar part such as a seat belt buckle D-ring, one or more portions
of the mold may be removed. In one embodiment, the top portion of
the mold may be removed to expose the outer, cosmetically
appealing, epidermal layer of the cultured leather. In one
embodiment, the top and bottom portions of the mold are removed,
allowing all sides of the engineered leather to be exposed.
[0046] In an optional fifth step 50, the leather is treated after
growth is complete. In one embodiment, treatment of the leather is
equivalent to tanning of the leather. In another embodiment, the
treatment process can include tanning and at least one of
preserving, soaking, bating, pickling, depickling, thinning,
retanning, lubricating, crusting, wetting, sammying, shaving,
rechroming, neutralizing, dyeing, fatliquoring, filling, stripping,
stuffing, whitening, fixating, setting, drying, conditioning,
milling, staking, buffing, finishing, oiling, brushing, padding,
impregnating, spraying, roller coating, curtain coating, polishing,
plating, embossing, ironing, glazing, tumbling, and any other
leather treatment known in the art.
[0047] In one embodiment, the leather can be treated free from the
entire mold. In another embodiment, the leather may be treated
while still associated with a portion of the mold.
[0048] In an optional tanning step, the leather may be tanned by
any known method, including using vegetable tannins; using at least
one chromium salt, in one embodiment a chromium sulfate; employing
aldehyde tanning; and tanning by use of aromatic polymers, referred
to as syntans.
[0049] When any desired combination of tanning and treatment steps
are complete, the engineered leather can be incorporated into an
article. In one case, a cover for a steering wheel which has been
treated without the presence of a portion of a mold can be fitted
over said steering wheel and stitched at a seam, which preferably
faces away from the driver.
[0050] In an optional step 60, further coatings (such as
wear-resistant, water resistant, and stain-resistant treatments)
can be applied to the leather. This step can occur prior to
attachment to the article or after it has been secured to the part
to be covered.
[0051] FIG. 2 illustrates a typical process for layering in the
manufacture of a leather-covered steering wheel. At first, an
armature 101 of a steering wheel 100 is provided with hub 102 at
its center and spokes connecting the hub 102 to the armature 101.
The armature 101 can be of any suitable material, particularly
aluminum or magnesium, and in any size and shape commensurate with
the size of the vehicle and driver's seat where it will be
employed.
[0052] In a first covering step 81, a layer of polyurethane (PU)
foam 110 is distributed substantially uniformly over a portion of
the surface of the armature 101. This layer provides a cushioned
grip to the user and also softens the steering wheel in case of
collision. In a second covering step 82, a heating element 120 is
optionally incorporated into the steering wheel. In a third
covering step 83, a layer of leather 130 is placed over the PU
foam. In a fourth covering step 84, the heating element is covered
with covering 140, which can be at least one of a wood veneer or a
leather. If leather, covering 140 may be identical to leather 130,
or may represent a second type or style of leather. If identical to
leather 130, the covering 140 may be continuous and integral with
leather 130, or may be a separate piece. Steps 82, 83, and 84 are
all optional, and steering wheels without heating elements, without
veneer trim, without a second type of leather, and with leather in
a single piece covering the entire steering wheel armature are all
considered to be within the scope and spirit of this invention.
[0053] Referring now to FIG. 3, a mold 350 for growing an
engineered leather cover for a steering wheel 300 is shown. The
mold has dimensions that are slightly larger than the steering
wheel 300 itself. In the illustrated embodiment, the mold 350 is
constructed of a single piece, although a mold having a top portion
and a bottom portion for cell growth in a space there between is
also a contemplated configuration. In the case of one-piece mold
350, the mold 350 has an outer surface and an inner surface. The
inner surface is adapted for cell growth. The single-piece mold has
a slit 303 running around at least a portion of the diameter of the
mold and serves to allow access to the inner surface. The slit 303
allows for introduction of cells into the mold, cell culture medium
and supplements during the growth phase, and importantly for
extraction of the engineered leather after culturing is
complete.
[0054] In a first step 391, cell paste 318 is deposited into the
interior of the mold which has been optionally treated to allow
cells to adhere, or, contrarily, to be biocompatible but prevent
substantial adhesion. After the cells are introduced, the mold is
placed in an incubator or bioreactor and maintained until the mold
is filled with an engineered leather of the desired size and shape.
In a second step 392, the engineered leather is extracted from the
mold, in one embodiment through the slit 303, and transferred or
bonded onto a steering wheel armature 300 which has an outermost
polyurethane (PU) foam layer 310. In a third step 393, the slit 303
is closed to form a new outer layer of the steering wheel by
stitches 313.
[0055] It is to be noted that the engineered leather coating can be
achieved in a number of ways. In one embodiment, a more traditional
and thicker leather may be grown within the mold and be treated as
usual. In other cases, a thinner piece of leather may suffice,
particularly if the construction of the PU foam layer of the
steering wheel (or other foams or cushions molded into the steering
wheel) can effectively simulate the feel of leather. In other
cases, such as a covering for an airbag, a thinner leather that
sufficiently gives a luxurious visual appearance, may be sufficient
to constitute a covering consistent with the principles of this
invention.
[0056] Growing a cultured leather in this manner has a great number
of advantages over obtaining leather in a conventional way. First,
there is little to no waste produced by cutting down a sheet of
leather when a molded engineered leather is utilized. Second,
treatment uses fewer toxic chemicals because of the minimized size
of the molded leather. Third, minimal shaping and stitching of
potentially tough leather is required. Fourth, no animal needs to
be acquired, raised, fed, housed, and ultimately slaughtered in the
production of the leather good. Fifth, this method is superior even
to other cultured leather methods because the prior art engineered
leather methods result in formation of a sheet of leather that must
still be cut to size and stitched like a conventional piece of
leather.
[0057] FIG. 4A illustrates a completed steering wheel 400 in
accordance with another embodiment of the present invention. In
this case, not only was cell paste introduced to the mold, but a
heating element 420 was incorporated as well. The heating element
420 as illustrated in FIG. 4A is a web of thermally-conductive
material which effectively extends around the entire circumference
of the steering wheel on which it is placed, although many
different configurations are envisioned to be within the scope of
the present invention, including but not limited to a
thermally-conductive heating element formed as a single coil, which
extends around only a portion of the circumference of the heating
element. Multiple heating elements 420 may also be incorporated.
The heating element 420 may be placed within the mold which is
adapted for cell growth and leather shaping therein. The heating
element 420 may optionally be treated to encourage cell adhesion to
its surface. The cell paste is spread not only through the interior
of the mold for cell growth but also makes contact with the heating
element 420. As the cells proliferate, they fill gaps in the
heating element, and in some embodiments grow over them,
surrounding them entirely in engineered leather. When growth and
treatment is complete, the combined leather/heating element is
placed over the steering wheel and stitched, with the heating
element being connected to a power source for operation during
times when warming is required.
[0058] In the embodiment illustrated in FIG. 4B, another variation
on the molded engineered leather is shown. In this case, a first
covering portion 430 made of cultured leather fashioned in a
striated pattern is shown. In this case the mold has features such
as for instance grooves in which the cell paste is deposited and
allowed to proliferate. The engineered leather can then be
extricated from the mold and placed over the steering wheel 400 to
form a decorative pattern on its own, or a second type of leather
440 with different tactile and/or visual characteristics can be
grown in the spaces between the striations to form a unique and
otherwise technically difficult to execute steering wheel
cover.
[0059] Referring now to FIG. 5A-5C, the advantages of employing a
cultured leather which has been grown in a separate mold or on the
article itself in covering a steering wheel over the existing prior
art method are described.
[0060] FIG. 5A illustrates a cross section of a prior art steering
wheel 500. In constructing such a steering wheel, a layer of PU
foam 510 forms the initial cushioning layer on the armature. Notch
541 is cut out of the PU foam layer 510, or molded during creation
of such a layer. Support 547 is laid over a portion of PU foam
layer 510 and veneer 540 is placed over support 547. A portion of
veneer 540 is placed into notch 541. Veneer 540 must be cut or
formed to have a variety of thickness and a non-uniform shape
across its length since it wends into the notch 541 and creates
another notch which is represented at butting junction 542.
[0061] Heating element 570 is positioned over another portion of PU
foam layer 510 and over a portion of veneer 540 proximate to
butting junction 542. Then leather 530 is stretched over heating
element 570 and into the notch formed by veneer 540 at butting
junction 542. At this point the leather is pulled into the notch in
the veneer and may be glued in. The leather is also stitched around
the steering wheel at a defined seam, and any excess must be
trimmed off.
[0062] In contrast, FIG. 5B illustrates a leather-and-veneer
steering wheel covering in accordance with the principles of the
present invention. In this case, the veneer 640 is laid in a
substantially uniform layer over the PU foam layer 610. The
engineered leather 630, which has been grown in a mold as described
previously in this disclosure, is slipped over the steering wheel
and creates a transition point 643 at the leather/veneer junction.
The leather can then be stitched around the steering wheel as
usual. Covering a steering wheel in this way is much simpler than
in the prior art and does not require cutting or forming pieces
into relatively complex geometries.
[0063] FIG. 5C shows a cross section of a steering wheel covering
which is similar to the one illustrated in FIG. 5B, but with an
artificial seam 648 placed at the transition point 643 between the
leather and veneer layers. Such a seam may have a decorative
purpose. The steering wheels of FIG. 5B and FIG. 5C can each
incorporate a heating element as part of their designs.
[0064] In an alternative embodiment, a seamless covering for an
article can be achieved by growing and treating an engineered
leather on the object to be coated itself. FIG. 6 shows a cross
section of a steering wheel undergoing the cell growth process. The
mold provides a uniform space for the cell paste to grow into and
create an engineered leather. A seamless covering creates no waste
leather and has an aesthetically pleasing appearance.
[0065] To create such a seamless covering, an armature 701 is
covered in a layer of PU foam 710, which is covered by a substrate
layer 715. The substrate layer 715 may be formed as a single piece
that has an interlock region 717 where the ends of the substrate
layer meet to form a cohesive whole after placement over the PU
foam layer. The substrate layer is a biocompatible surface which
encourages adhesion of cells and/or ECM.
[0066] Cell paste 730, which may optionally be in the form of
sheets or strips, is posited upon the substrate layer 715. Then
mold 750 is placed around the entire armature assembly. The mold
750 has a top portion 752 and a bottom portion 754 that come
together to create a closed mold configuration which has a space
therein for cell growth. The cells are maintained as usual with
fresh media supplied as necessary, and when the engineered leather
has attained the proper thickness, the mold is removed and the
leather is treated in situ. This allows for an entirely seamless
covering for the article.
[0067] In some cases where the leather is grown for a substantially
flat surface, such as for covering a tongue or adjustable turning
loop of a seat belt assembly, the mold may simply be a flat plate
on which the leather is cultured. In such a case the mold itself
can be made of a suitable material which has an appearance similar
to the components of the automobile interior, and fixed to the
portion of the car to be covered, such as by gluing, snapping into
place, or any other means. This would prevent a step of dislodging
the engineered leather from the substrate upon which it was grown,
minimizing the chances of tearing or deformation.
[0068] Referring now to FIG. 7A-7C, other components of an
automotive interior that can be covered with a cultured leather are
shown.
[0069] FIG. 7A-7B show a driver-side airbag cover 800 having a
substrate layer 815 which is set over a base member 822, or
alternatively an airbag cover in which the substrate layer and base
member are molded as a monolithic assembly. A leather covering 830
can be engineered to have slits 803 within it at the points where
the airbag, upon deployment, would inflate. The leather could be
cultured as multiple pieces for each disconnected portion of the
airbag surface, or could be formed as a single preformed piece
having very thin breakable portions which are configured to tear
when the airbag inflates and deploys.
[0070] FIG. 7C illustrates a seat belt assembly 840. Because the
portions of a seat belt assembly which could be covered in leather
are small, at present such coverings are not made because it can be
hard to work with such small pieces of leather. However, a cultured
leather in a properly-shaped mold could facilitate the creations of
such coverings. Components of a seatbelt that could be covered in
an engineered leather include but are not limited to a pushbutton,
an adjustable turning loop 861, a tongue 863, a D-ring, or a buckle
assembly 865. In the case of small articles like these seat belt
components, as well as a seat belt buckle pushbutton or a cover for
a gear shift handle, an engineered leather can optionally be grown
directly on the article itself for increased ease in handling.
[0071] Further components of an automobile interior could also have
molds designed for them such that an appropriate leather covering
could be cultured. These components include gearshifts, door
panels, seats, glove box exteriors, dashboard enclosures, and the
like.
[0072] Referring now to FIG. 8A-8C, a variety of molds for
culturing an engineered leather are illustrated. Such molds are
useful in that they do not directly correlate to a particular
article to be covered by the generated engineered leather, but
instead provide a preshaped leather that can be used in a variety
of contexts. For instance, a cylindrical mold can have a surface
upon which a leather can be cultured. The mold may have a concave
surface for cell growth, or a convex surface for cell growth. It
may be a mold of one-piece construction, or two-piece construction,
or the mold may be made up of more than two pieces. The mold will
have an opening through which a cell paste can be applied to the
cell growth surface of the mold, and which will allow for
extraction of the engineered leather after culturing is
complete.
[0073] FIG. 8A illustrates a mold 901 of single-piece construction.
This mold has an inner concave surface 902 upon which a cell
aggregate can be placed for culturing. The resultant leather will
have a substantially cylindrical shape and can be treated and then
cut to the desired length for use in a covering application. FIG.
8B shows a two-piece mold 910 comprising an inner, solid cylinder
911, and an outer, hollow cylinder 913. The positioning of inner
cylinder 911 within the lumen 914 of outer cylinder 913 creates a
cell growth space within lumen 914. A cell aggregate can be placed
on convex inner cylinder surface 912. The extent of proliferation
and therefore the dimensions of the resultant leather will be
constrained by the inner surface of outer cylinder 913. Finally,
FIG. 8C shows a semicylindrical mold 920 having a concave inner
surface 921. In one embodiment, cells can be grown on the surface
of one of these semicylindrical molds to form a leather with a
semicylindrical shape. In another embodiment, two semicylindrical
molds 920 can be placed in contact with one another to form a fully
cylindrical mold with the result of a cylindrical cultured
leather.
[0074] In another embodiment, the engineered leather can be grown
in trays that represent the two-dimensional surface of an object to
be covered thereby. The final assembly steps, such as sewing or
bonding of the engineered leather, then provides the
three-dimensional finish.
[0075] The leather can be removed from the mold, tanned and treated
in any number of postprocessing steps, including dyeing, and stored
for later use in any application that can use a substantially
cylindrical piece of leather in a downstream application. Growth in
the three-dimensional, substantially cylindrical configuration
allows for basal structures such as ECM to form in such a way that
can strengthen the preshaped engineered leather and help it keep
its shape. An engineered leather created in this way can not only
be cut to the correct length after storage but also to a desired
thickness as necessary.
[0076] While the materials and methods of the invention have been
described above with reference to certain specific embodiments
thereof, it is to be clearly understood that these embodiments have
been given for purposes of illustration only and are not intended
to be limiting. The scope of the invention is bounded only by the
scope of the claims which are set out hereafter.
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