U.S. patent application number 14/631466 was filed with the patent office on 2015-06-18 for sheet molding compound with cores.
The applicant listed for this patent is Magna International Inc.. Invention is credited to Louis Dodyk, Jeremy A. Panasiewicz, Jeffrey R. Robbins.
Application Number | 20150165696 14/631466 |
Document ID | / |
Family ID | 43798780 |
Filed Date | 2015-06-18 |
United States Patent
Application |
20150165696 |
Kind Code |
A1 |
Robbins; Jeffrey R. ; et
al. |
June 18, 2015 |
SHEET MOLDING COMPOUND WITH CORES
Abstract
A component made of at least one thermoformable material, having
a first layer made of a first material, a second layer made of a
second material, and a third layer made of the first material. The
three layers form a sheet, which is formed to various shapes,
depending upon the part that is to be created. The sheet may be
formed to produce the bumper of an automobile, a door panel for an
automobile, a flotation device, such as a pontoon for a pontoon
boat, or the like. The first and third layers are SMC, and the
second layer, or "core," is disposed between the first and third
layers, allowing the strength of the first and third layers to be
used more efficiently, compared to a sheet having only the first
and third layers, and no core.
Inventors: |
Robbins; Jeffrey R.; (Ann
Arbor, MI) ; Panasiewicz; Jeremy A.; (Macomb, MI)
; Dodyk; Louis; (Marion, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Magna International Inc. |
Aurora |
|
CA |
|
|
Family ID: |
43798780 |
Appl. No.: |
14/631466 |
Filed: |
February 25, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12928803 |
Dec 20, 2010 |
8992813 |
|
|
14631466 |
|
|
|
|
61284486 |
Dec 18, 2009 |
|
|
|
Current U.S.
Class: |
416/229R ;
428/213; 428/423.1; 428/423.5; 428/425.6; 428/430; 428/441;
428/442; 428/475.2; 428/476.9; 428/482; 428/522 |
Current CPC
Class: |
B29L 2031/30 20130101;
B32B 27/32 20130101; Y10T 428/31649 20150401; B32B 2603/00
20130101; Y10T 428/2495 20150115; Y10T 428/30 20150115; Y10T
428/31736 20150401; B29C 70/18 20130101; Y10T 428/31757 20150401;
Y10T 428/31645 20150401; Y02P 70/523 20151101; B32B 27/40 20130101;
Y10T 428/31725 20150401; Y10T 428/31794 20150401; B32B 2262/0269
20130101; Y10T 428/31938 20150401; B32B 27/08 20130101; B32B
2262/101 20130101; B29L 2031/085 20130101; Y10T 428/249921
20150401; Y10T 428/31601 20150401; B29C 70/086 20130101; B29L
2031/08 20130101; B32B 27/36 20130101; B32B 2260/021 20130101; B32B
2307/738 20130101; F03D 1/0675 20130101; Y02E 10/721 20130101; Y10T
428/31616 20150401; B32B 2262/106 20130101; Y10T 428/163 20150115;
Y10T 428/31562 20150401; B29K 2105/0872 20130101; Y02P 70/50
20151101; Y10T 428/31935 20150401; B29C 70/865 20130101; Y10T
428/31551 20150401; B32B 2250/03 20130101; Y02E 10/72 20130101;
Y10T 428/31855 20150401; B29D 99/0025 20130101; B29K 2101/12
20130101 |
International
Class: |
B29C 70/08 20060101
B29C070/08; F03D 1/06 20060101 F03D001/06; B32B 27/08 20060101
B32B027/08; B32B 27/36 20060101 B32B027/36; B32B 27/32 20060101
B32B027/32; B29C 70/18 20060101 B29C070/18; B32B 27/40 20060101
B32B027/40 |
Claims
1. An automotive component made of at least one thermoformable
material, comprising: a first structural layer made of a first
material; a spatial support layer made of a second material; and a
third structural layer made of said first material, said spatial
support layer being disposed between said first structural layer
and said third structural layer; wherein said first structural
layer, said spatial layer, and said third structural layer are
placed into a mold, and said mold his heated such that said first
structural layer and said third structural layer are chemically
bonded to said spatial support layer.
2. The automotive component made of at least one thermoformable
material of claim 1, each of said first structural layer and said
third structural layer further comprising a thermoformable,
pre-impregnated sheet molding compound (SMC).
3. The automotive component made of at least one thermoformable
material of claim 2, wherein said thermoformable, preimpregnated
SMC further comprises a thermoset material, a polymer resin, inert
fillers, a fiber reinforcement, catalysts, pigments and
stabilizers, release agents, thickeners, and combinations
thereof.
4. The automotive component made of at least one thermoformable
material of claim 1, each of said first structural layer and said
third structural layer further comprising a pre-impregnated
material.
5. The automotive component made of at least one thermoformable
material of claim 4, said pre-impregnated material being one
selected from the group consisting of Glass Mat Thermoplastic (GMT)
material, Kevlar, E-Glass, a carbon fiber material, a composite
fiber material, and combinations thereof.
6. The automotive component made of at least one thermoformable
material of claim 1, wherein said spatial support layer is made of
a material which is one selected from the group consisting of
polyester, polypropylene, polyurethane, polyvinylchloride (PVC),
styrene acrylonitrile resin (SAN), and combinations thereof.
7. The automotive component made of at least one thermoformable
material of claim 1, wherein said first structural layer and said
third structural layer are substantially the same thickness.
8. The automotive component made of at least one thermoformable
material of claim 1, wherein said first structural layer and said
third structural layer are of different thicknesses.
9. The automotive component made of at least one thermoformable
material of claim 1, wherein said spatial support layer is of a
greater thickness compared to said first structural layer and said
third structural layer.
10-15. (canceled)
16. A wind blade made of at least one thermoformable material,
comprising: a top structural layer made of a sheet molding
compound; a middle support layer made of a polymer material, said
middle support layer having a first side and a second side; and a
bottom structural layer made of said sheet molding compound;
wherein said top structural layer is bonded to first side of middle
support layer, and said bottom structural layer is bonded to said
second side of said middle support layer, forming a sheet.
17. The wind blade made of at least one thermoformable material of
claim 16, wherein said polymer is one selected from the group
consisting of polyester, polypropylene, polyurethane,
polyvinylchloride (PVC), styrene acrylonitrile resin (SAN), and
combinations thereof.
18. The wind blade made of at least one thermoformable material of
claim 16, wherein said sheet molding compound further comprises a
thermoset material, a polymer resin, inert fillers, a fiber
reinforcement, catalysts, pigments and stabilizers, release agents,
thickeners, and combinations thereof.
19. The wind blade made of at least one thermoformable material of
claim 16, wherein said top structural layer and said bottom
structural layer are of a first thickness.
20. The wind blade made of at least one thermoformable material of
claim 19, wherein said first thickness is generally from about 1.0
millimeters to about 5.0 millimeters, typically about 1.0
millimeters to about 2.0 millimeters, and preferably about 1.3
millimeters to about 1.7 millimeters.
21. The wind blade made of at least one thermoformable material of
claim 16, wherein said middle support layer is of a thickness which
is generally from about 1.0 millimeters to about 50.8 millimeters,
typically about 1.0 millimeters to about 25.4 millimeters, and
preferably about 1.0 millimeters to about 5.0 millimeters.
22. The wind blade made of at least one thermoformable material of
claim 16, wherein said sheet is placed into a mold and cured to
bond said top structural layer to said middle support layer, and to
bond said bottom structural layer to said middle support layer.
23. The wind blade made of at least one thermoformable material of
claim 22, wherein said sheet is cured at a temperature of generally
in the range of about 200.degree. Fahrenheit to about 400.degree.
Fahrenheit, typically in the range of about 250.degree. Fahrenheit
to about 350.degree. Fahrenheit, and preferably in the range of
about 280.degree. Fahrenheit to about 320.degree. Fahrenheit.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application No. 61/284,486 filed on Dec. 18, 2009. The disclosure
of the above application is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a sheet molding compound
which includes a core for providing additional strength and reduced
weight in a molded, one-piece part.
BACKGROUND OF THE INVENTION
[0003] Molding of various plastic materials is a common method used
to create parts for various applications. One specific method of
producing parts in this manner is through the use of a sheet
molding compound (SMC). Several examples of SMC methods are Long
Fiber Injection (LFI), Structural Reaction Injection Molding
(SRIM), Reinforced Reaction Injection Molding (RRIM), or Vacuum
Assisted Resin Transfer Molding (VARTM).
[0004] The method of making a part using LFI involves the use of
fiberglass cut into long strands, or fibers, mixed with a resin to
provide additional strength to a molded part. SRIM molding is
similar to typical injection molding, except that thermosetting
polymers are used, and the two parts of the polymer are mixed
together an injected into a mold under high pressure, and are then
allowed to cure. A reinforcing agent is used, such as glass
fillers, in the mixture for improved strength. RRIM is another type
of SRIM, in which a fiber mesh is used as the reinforcing agent;
the fiber mesh is placed in the mold and the polymer mixture is
then injection molded over it. VARTM is a process in which resin is
inserted into a mold which contains layers of fibers or a preform;
flow of resin is assisted by a vacuum in the mold.
[0005] There has been an increasing desire to create parts that are
not completely solid, but rather have a type of insert in between
layers of SMC. Having a part which is not completely solid is less
costly, and is typically lighter in weight, while more effectively
using the strength of the SMC.
[0006] While each of the methods described above has different
advantages, for example, such as different types of resins may be
used, they have also been met with various drawbacks in that each
one of the above-mentioned processes requires additional
manufacturing steps, increased tooling, and increased difficulty of
assembly. Additionally, incorporating one of the above-mentioned
manufacturing processes while using an insert to reduce the amount
of SMC necessary requires the use of a heavy insert because a
lightweight insert becomes crushed during the molding process.
[0007] Accordingly, there exists a need for a method of producing
parts by molding an SMC over an insert or core which is lightweight
and can withstand the various pressures and temperatures of
molding, while maintaining a high strength to weight ratio.
SUMMARY OF THE INVENTION
[0008] The present invention is directed to a component made of at
least one thermoformable material, having a first layer made of a
first material, a second layer made of a second material, and a
third layer made of the first material. The second layer is
disposed between the first layer and the third layer such that the
first layer and the third layer are bonded to the second layer.
[0009] The three layers form a sheet, which is formed to various
shapes, depending upon the part that is to be created. The sheet
may be formed to produce the bumper of an automobile, a door panel
for an automobile, a flotation device, such as a pontoon for a
pontoon boat, a surf board, a backboard for a basketball hoop, body
panels for home appliances such as refrigerators or freezers,
running boards for an automobile, wind blades, or the like.
[0010] The first and third layers are SMC, and the second layer, or
"core," is disposed between the first and third layers, allowing
the strength of the first and third layers to be used more
efficiently, compared to a sheet having only the first and third
layers, and no core.
[0011] Further areas of applicability of the present invention will
become apparent from the detailed description provided hereinafter.
It should be understood that the detailed description and specific
examples, while indicating the preferred embodiment of the
invention, are intended for purposes of illustration only and are
not intended to limit the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The present invention will become more fully understood from
the detailed description and the accompanying drawings,
wherein:
[0013] FIG. 1 is a sectional side view of a sheet molding compound
(SMC) around a core, according to the present invention;
[0014] FIG. 2 is a first example of a graph showing strength versus
deflection properties of a sheet of material made with an SMC and a
core, according to the present invention;
[0015] FIG. 3 is a second example of a graph showing strength
versus deflection properties of a sheet of material made with an
SMC and a core, according to the present invention;
[0016] FIG. 4 is an example of a graph showing strength versus
deflection properties of a sheet of material made with an SMC with
no core, according to the present invention;
[0017] FIG. 5 is a first perspective view of a one-piece wind blade
made using an SMC, according to the present invention;
[0018] FIG. 6 is a second perspective view of a one-piece wind
blade made using an SMC, according to the present invention;
[0019] FIG. 7 is a sectional view taken along lines 7-7 of FIG. 6,
according to the present invention;
[0020] FIG. 8 is an exploded view of a one-piece wind blade made
using an SMC, according to the present invention; and
[0021] FIG. 9 is a perspective view of a one-piece wind blade made
using an SMC, prior to being inserted into a mold, according to the
present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] The following description of the preferred embodiment(s) is
merely exemplary in nature and is in no way intended to limit the
invention, its application, or uses.
[0023] A section of a sheet of material made through the use of a
sheet molding compound (SMC) process according to the present
invention is shown in FIG. 1 generally at 10. SMC material may
consist of, but are not limited to, a thermoset material, a polymer
(such as polyester or vinylester) resin, inert fillers, fiber
reinforcement, catalysts, pigments and stabilizers, release agents,
and thickeners. The sheet 10 includes a first structural layer or
top layer 12 along with a second or middle support layer, also
referred to as a spatial support layer, or "core," 14, and a third
structural layer or bottom layer 16. In an alternate embodiment,
instead of SMC, the structural layers 12,16 are another type of
pre-impregnated or "pre-preg" material, such as a Glass Mat
Thermoplastic (GMT) material, Kevlar, E-Glass, carbon fiber
materials, or any other pre-impregnated composite fiber
material.
[0024] In this embodiment, the top layer 12 and bottom layer 16 are
of a first thickness 18 of generally from about 1.0 millimeters to
about 5.0 millimeters, typically about 1.0 millimeters to about 2.0
millimeters, and preferably about 1.3 millimeters to about 1.7
millimeters, and in a preferred embodiment the top layer 12 and the
bottom layer 16 are each about 1.5 millimeters in thickness.
[0025] The middle support layer 14 is of a second thickness 20,
which is generally from about 1.0 millimeters to about 50.8
millimeters, typically about 1.0 millimeters to about 25.4
millimeters, and preferably about 1.0 millimeters to about 5.0
millimeters. In the preferred embodiment, the core 14 is about 3.0
millimeters in thickness. The core 14 has a first side 22 and a
second side 24; the top layer 12 is connected to the first side 22,
and the bottom layer 16 is connected to the second side 24, the
function of which will be described later.
[0026] The core 14 is made of one or more of many various
materials, such as, but not limited to, polyesters, polypropylenes,
polyurethanes, polyvinylchloride (PVC), or styrene acrylonitrile
resin (SAN). Other types of materials may be suitable, depending
upon the application and the amount of strength desired.
Preferably, a light weight, low density foam made from these
materials is used. The material selected preferably chemically
bonds with the SMC material during molding. In one embodiment, the
core 14 is a polymer core made of any suitable polymer.
[0027] Each of the top layer 12 and bottom layer 16 is made of an
SMC material. To create the desired part, the core 14 is placed
between the layers 12,16 of SMC material, and the entire assembly
is placed into a heated molding tool, such as a mold. The top layer
12 and bottom layer 16 are flexible enough to allow for some
bending when the layers 12,16 are placed in the mold to facilitate
the shaping of the part. The mold may be of any shape, and in an
alternate embodiment, the layers 12,16 are wrapped around the core
14 and placed in the mold. The layers 12,16 are also flowable when
the mold is heated, which further facilitates the forming of the
finished component. Additional charge material may be forced into
the mold if necessary, to provide the desired shape if the layers
12,16 do not provide enough material to complete the finished
component. The core 14 is also compressible, and can be partially
pre-formed in the shape of the finished component, which also
facilitates shaping of the component in the mold. In an alternate
embodiment, the core 14 is used for providing spacing between the
layers 12,16 only in certain areas of the sheet 10, where increased
strength is needed most.
[0028] The tool is closed under a desired temperature and pressure,
and the part cures. The part is removed from the tool as a
one-piece part. In this embodiment, the assembly is cured at a
temperature of generally in the range of about 200.degree.
Fahrenheit to about 400.degree. Fahrenheit, typically in the range
of about 250.degree. Fahrenheit to about 350.degree. Fahrenheit,
and preferably in the range of about 280.degree. Fahrenheit to
about 320.degree. Fahrenheit. In a preferred embodiment, the cure
temperature is about 300.degree. Fahrenheit, however, it is within
the scope of the invention that the cure temperature may be more of
less than 300.degree. Fahrenheit, depending on the application, and
the materials chosen for the layers 12,16 and the core 14.
[0029] The process is used to create various types of parts, such
as components requiring maximum structural properties (e.g.,
floorboards of an automobile, or the bed of a semi-trailer), or
components which are semi-structural (e.g., devices used for
flotation, such as pontoons for a pontoon boat). The process
described above is also for use in producing parts having a
high-quality finish, such as a "Class-A" surface, which is required
for components having a high-gloss finish, such as a door panel or
a bumper for an automobile. Other components may also be created
using the process described above, such as a surf board, a
backboard for a basketball hoop, body panels for home appliances
such as refrigerators or freezers, other appliances such as
furnaces or air conditioners, running boards for an automobile, or
a ramp for a trailer used to transporting an automobile,
motorcycle, or the like.
[0030] Referring to FIGS. 5-9, one embodiment of the present
invention is shown as a one-piece wind blade 26, and the layers
12,14,16 are of made from a material such that when the blade 26 is
a finished component, the blade 26 is strong enough to pass the
strength requirements regulated by the International
Electrotechnical Commission (IEC). During the manufacturing
process, the top layer 12 and bottom layer 16 are several different
individually cut sheets 46 of different sizes, best seen in FIG. 9.
It can also be seen in FIG. 9 that additional sheets 46 are used
along different areas of the blade 26 for providing a different
contour or thickness, depending upon the desired shape of the blade
26. Furthermore, more or less sheets 46 may used, and cut to
different sizes to facilitate forming the blade 26 to be of a
different size, shape, or to have the layers 12,16 of different
thicknesses. There is also an additional sheet 46 in roll form,
shown generally at 48 placed at one end of the blade 26 which is
used for forming a connector 50, shown in FIGS. 6 and 8. The blade
26 as shown in FIG. 9 is placed into a mold, and as the mold is
heated, the sheets 46 melt to form the shape of the blade 26.
[0031] With regard to the thickness of the layers 12,14,16, it
should be noted that it is within the scope of the invention that
the top layer 12 and bottom layer 14 may be of greater or lesser
thicknesses. It is also within the scope of the invention that the
top layer 12 and the bottom layer 14 may also be of different
thicknesses. Furthermore, the core 14 may have a greater or lesser
thickness, depending upon the application and the type of material
used to produce the core 14.
[0032] Referring to FIGS. 2 and 3, examples of strength versus
deflection curves are shown which were created by testing (a
three-point bend test) several sheets 10 produced according to the
present invention. In FIG. 2, the sheets 10 used for the test
included a top layer 12 and bottom layer 16 having a 1.5 millimeter
in thickness, while the core 14 was 3.0 millimeters thickness. FIG.
2 includes a first deflection curve 28, a second deflection curve
30, and a third deflection curve 32 representing three different
tests performed on three different sheets. In FIG. 3, the sheets 10
used for testing included a top layer 12 and bottom layer 16 of 1.5
millimeters in thickness, and a core 14 of 12.0 millimeters in
thickness. FIG. 3 includes a fourth deflection curve 34, a fifth
defection curve 36, and a sixth deflection curve 38, representing
three different tests performed on three different sheets. Both of
these examples in FIGS. 2 and 3 show improvement over a sheet 10
tested with no core, shown in FIG. 4. FIG. 4 shows three strength
versus deflection curves. More specifically, FIG. 4 shows a seventh
deflection curve 40, an eighth deflection curve 42, and a ninth
deflection curve 44, representing three different tests from three
different sheets 10, with each sheet having an overall thickness of
3.0 millimeters (and no core 14), which is the equivalent of the
combined thickness of two layers of 1.5 millimeters in
thickness.
[0033] The description of the invention is merely exemplary in
nature and, thus, variations that do not depart from the essence of
the invention are intended to be within the scope of the invention.
Such variations are not to be regarded as a departure from the
spirit and scope of the invention.
* * * * *