U.S. patent number 10,336,878 [Application Number 15/600,197] was granted by the patent office on 2019-07-02 for microcellular foam extension dash panel.
This patent grant is currently assigned to FORD MOTOR COMPANY. The grantee listed for this patent is FORD MOTOR COMPANY. Invention is credited to Paul Kenneth Dellock, Michael A. Musleh, Paulina Vazquez Orpinel, Stuart C. Salter, Ana Valeria Vazquez.
United States Patent |
10,336,878 |
Dellock , et al. |
July 2, 2019 |
Microcellular foam extension dash panel
Abstract
A composition for the manufacture of temperature resistant and
sound attenuating automotive parts includes polyethylene
terephthalate resin, basalt fibers, and mica. The basalt fibers and
mica may be between 35 and 40% of the composition by weight of the
total composition. The basalt fibers may be between 20 and 30% of
the composition by weight and the mica may be between 5 and 15% of
the composition by weight. The basalt fibers may be 25% of the
composition by weight and the mica may be 10% of the composition by
weight. A method is disclosed for molding a temperature resistant
and sound attenuating part by blending a foaming agent with a
thermoplastic olefin, basalt fibers and mica to form a resin
mixture. The resin mixture is injected under pressure into a die to
fill the die. The pressure is reduced to allow the foaming agent to
form a microcellular core.
Inventors: |
Dellock; Paul Kenneth
(Northville, MI), Salter; Stuart C. (White Lake, MI),
Orpinel; Paulina Vazquez (Mexico City, MX), Musleh;
Michael A. (Canton, MI), Vazquez; Ana Valeria (Mexico
City, MX) |
Applicant: |
Name |
City |
State |
Country |
Type |
FORD MOTOR COMPANY |
Dearborn |
MI |
US |
|
|
Assignee: |
FORD MOTOR COMPANY (Dearborn,
MI)
|
Family
ID: |
64270448 |
Appl.
No.: |
15/600,197 |
Filed: |
May 19, 2017 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20180334546 A1 |
Nov 22, 2018 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08K
3/346 (20130101); C08J 9/0095 (20130101); C08J
9/0066 (20130101); C08J 9/0061 (20130101); C08L
67/02 (20130101); C08K 7/04 (20130101); C08L
23/14 (20130101); C08J 9/0085 (20130101); C08K
3/02 (20130101); C08L 23/14 (20130101); C08L
51/06 (20130101); C08K 3/34 (20130101); C08K
3/346 (20130101); C08L 67/02 (20130101); C08K
7/04 (20130101); C08L 67/02 (20130101); C08L
67/02 (20130101); C08L 67/02 (20130101); C08K
7/04 (20130101); C08K 3/34 (20130101); C08L
67/02 (20130101); C08L 67/02 (20130101); C08K
7/04 (20130101); C08K 3/34 (20130101); C08K
2003/023 (20130101); C08J 2300/30 (20130101); C08K
2201/016 (20130101); C08J 2323/14 (20130101); C08J
2367/02 (20130101); C08J 2451/06 (20130101); C08K
2003/026 (20130101) |
Current International
Class: |
C08J
9/04 (20060101); C08J 9/06 (20060101); C08J
9/08 (20060101); C08J 9/10 (20060101); C08J
9/00 (20060101); C08K 3/02 (20060101); C08L
23/14 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
102731903 |
|
Oct 2012 |
|
CN |
|
2010017254 |
|
Feb 2010 |
|
WO |
|
Other References
MICAMAFCO, "Mica Composite", www.micaworld.in/micacomposite.html, 2
pgs, retrieved Dec. 16, 2016. cited by applicant.
|
Primary Examiner: Boyle; Kara B
Attorney, Agent or Firm: Coppiellie; Raymond L. Brooks
Kushman P.C.
Claims
What is claimed is:
1. A method of molding a temperature resistant and sound
attenuating part comprising: blending a foaming agent with a
thermoplastic, basalt fibers and mica to form a resin mixture;
injecting the resin mixture into an injection mold at a pressure
between 10,000 and 125 MPa; holding the pressure in the mold until
the mold is fully filled; and reducing the pressure in the mold to
a pressure of 7 MPa or less.
2. The method of claim 1 wherein the basalt fibers and mica are
between 35 and 40% of the resin mixture by weight.
3. The method of claim 1 wherein the basalt fibers are between 10
and 25% of the resin mixture by weight and the mica is between 5
and 10% of the resin mixture by weight.
4. The method of claim 3 wherein the basalt fibers are 25% of the
resin mixture by weight and the mica is 10% of the resin mixture by
weight.
5. The method of claim 4 wherein the mica has an aspect ratio of
more than 80:1.
6. The method of claim 1 wherein the thermoplastic is a mixture of
virgin polyethylene terephthalate resin and recycled polyethylene
terephthalate resin.
7. The method of claim 6 wherein the polyethylene terephthalate
resin is 50% virgin polyethylene terephthalate resin and 50%
recycled polyethylene terephthalate resin.
8. The method of claim 7 wherein the resin mixture further includes
a flow enhancer selected from the group consisting of: phosphonium
tetraborate salt; and trihexyl(tetradecyl)phosphonium.
9. The method of claim 1 wherein during the step of injecting the
resin mixture into the mold the basalt fibers and mica are oriented
parallel to a direction of flow of the resin mixture.
10. The method of claim 9 wherein during the step of holding the
pressure in the mold until the mold is fully filled, the basalt
fibers and mica are solidified in an outer wall.
11. The method of claim 10 wherein during the step of reducing the
pressure in the injection mold, a gas contained in the foaming
agent expands to fill a space between the outer walls to form an
interior foamed cellular structure.
12. The method of claim 1 further comprising: compatibilizing the
basalt fibers and mica by adding maleic anhydride grafted
polypropylene to the resin mixture.
Description
TECHNICAL FIELD
This disclosure relates to a composition and a method of
manufacturing a part that has a high heat deflection temperature
and sound attenuation properties.
BACKGROUND
Vehicles are being developed that have reduced weight and improved
fuel economy. Turbochargers are being incorporated into engine
designs to compensate for reductions in engine displacement as part
of the effort to improve fuel economy. Lower displacement engines
provided with turbochargers run at higher revolutions per minute
(RPMs) and generate more noise than engines having similar torque
output. The exhaust side of turbochargers generate high heat
particularly after the engine is turned off and air circulation is
minimized.
Cowl structures are used to attenuate noise from the engine. Cowl
structures include extension dash panels (EDPs) that are removable
to facilitate engine servicing. Prior art EDPs may be manufactured
from stamped steel or aluminum or may be made of sheet molding
compounds (SMCs). EDPs made of stamped metal or SMC add weight and
increase the cost of the parts and cost of labor for installation.
Layers of sound absorbing insulation may be needed to reduce the
transmission of engine noise into the passenger compartment of the
vehicle. The layers of sound absorbing material are attached with
fasteners that also add weight and increase part cost and assembly
labor.
EDPs are subjected to high heat in the engine compartment and may
be installed near the turbocharger exhaust area. EDPs made of
common thermoplastic material may melt or be distorted when exposed
to the high temperatures in the engine compartment of a vehicle
near a turbocharger. Heat shields may be required to protect the
EDP from the heat generated by the turbocharger exhaust. The heat
shields may include foam layers between the EDP and the heat
shields to absorb and deflect heat.
This disclosure is directed to solving the above problems and other
problems as summarized below.
SUMMARY
According to one aspect of this disclosure, a composition is
disclosed that consists essentially of polyethylene terephthalate
resin, basalt fibers, and mica.
The basalt fibers and mica contained in the composition may be
between 35 and 40% of the composition by weight. The basalt fibers
may be between 20 and 30% of the composition by weight and the mica
may be between 5 and 15% of the composition by weight. More
specifically, the basalt fibers may be 25% of the composition by
weight and the mica may be 10% of the composition by weight. The
mica may have an aspect ratio of more than 80:1.
The polyethylene terephthalate resin may be recycled polyethylene
terephthalate resin combined in any proportion with virgin
polyethylene terephthalate resin. Alternatively, the polyethylene
terephthalate resin may be 50% virgin polyethylene terephthalate
resin and 50% recycled polyethylene terephthalate resin.
The polyethylene terephthalate is compatibilized with the basalt
fibers and mica by adding maleic anhydride grafted polypropylene
coupling agent. The coupling agent increases the bond of the mica
and basalt fibers to the base resin improving impact properties and
stiffness. Between 1 and 4% by weight maleic anhydride grafted
polypropylene coupling agent is used.
The composition may further comprise a flow enhancer including
phosphonium tetraborate salt or
trihexyl(tetradecyl)phosphonium.
According to another aspect of this disclosure, a method is
disclosed for molding a temperature resistant and sound attenuating
part. The method begins by blending a foaming agent with a
thermoplastic olefin, basalt fibers and mica to form a resin
mixture. The resin mixture is then injected into an injection mold
at a pressure between 70 Megapascal (MPa) and 125 MPa. The pressure
in the mold is held until the mold is fully filled. The pressure in
the mold is then reduced to a pressure of 7 MPa or less to allow
the foam to expand and completely fill the mold.
According to additional aspects relating to a method of making a
heat resistant and noise dampening panel, during the step of
injecting the resin mixture into the mold the basalt fibers and
mica are oriented by the flow of the resin mixture parallel to the
direction of flow of the resin mixture. The basalt fibers and mica
are solidified in an outer wall during the step of holding the
pressure in the mold until the mold is fully filled. A gas
contained in the foaming agent expands to fill the space between
the outer walls to form an interior foamed cellular structure
during the step of reducing the pressure in the mold.
The above aspects of this disclosure and other aspects will be
described below with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary top plan view of a vehicle in phantom lines
with an extension dash panel shown in solid lines.
FIG. 2 is a cross-section view taken along the line 2-2 in FIG.
1.
FIG. 3 is a diagrammatic front elevation view of an injection
molding machine made according to one aspect of this
disclosure.
FIG. 4 is a graph of the pressure in the mold over time comparing
the disclosed foam molding process compared to a conventional
molding process.
FIG. 5 is a fragmentary cross section view of a part including a
thermoplastic olefin skin and a foamed thermoplastic olefin core as
it is formed with controlled back pressure.
FIG. 6 is a diagrammatic cross section view of a part made
according to one aspect of this disclosure showing basalt fibers
and mica in the thermoplastic olefin skin aligned in the direction
of flow of the material as the material is injected into the
injection molding die.
DETAILED DESCRIPTION
The illustrated embodiments are disclosed with reference to the
drawings. However, it is to be understood that the disclosed
embodiments are intended to be merely examples that may be embodied
in various and alternative forms. The figures are not necessarily
to scale and some features may be exaggerated or minimized to show
details of particular components. The specific structural and
functional details disclosed are not to be interpreted as limiting,
but as a representative basis for teaching one skilled in the art
how to practice the disclosed concepts.
This disclosure provides compositions for the manufacture of
temperature resistant and sound attenuating automotive parts. The
composition comprises, preferably consists essentially of and more
preferably consists of polyethylene terephthalate resin, basalt
fibers, and mica.
Referring to FIG. 1, a vehicle 10 is partially illustrated in
phantom to show an extension dash panel 12 installed in the vehicle
10. The extension dash panel 12 is assembled in the vehicle 10 to
be removable for vehicle service and extends from the dash panel 14
forward and into the rear portion of the engine compartment 16.
Referring to FIG. 2, the extension dash panel 12 is shown in cross
section attached to the dash panel 14 and below the windshield 18
of the vehicle 10. An engine 20 and turbocharger 22 are
diagrammatically illustrated below the extension dash panel 12. The
extension dash panel 12 includes a skin layer 24 on a top side 26
and a bottom side 28. A microcellular foam core 30 is disposed
between the top and bottom sides 26, 28 of the extension dash panel
12. References to the top and bottom sides are to the relative
positions in FIG. 2, but the part may be oriented in other
positions and that there are vertically extending portions of the
extension dash panel 12.
Referring to FIG. 3, an example of an injection molding machine 32
is illustrated. The injection molding machine 32 includes a blender
34 that receives thermoplastic olefin pellets 36 and a foaming
agent 38. Instead of thermoplastic olefin pellets,
acrylic-styrene-acrylonitrile (ASA) polymer pellets may be used in
the process. The pellets 36 and foaming agent 38 are blended
together in the blender 34 (with other constituents such as basalt
fibers, mice, phosphonium tetraborate salt or
trihexyl(tetradecyl)phosphonium, and maleic anhydride grafted
polypropylene) and supplied to a plasticizing barrel 40 where the
mixture is heated to a molten state. The heated mixture is injected
into an injection molding die 42 at a high molding pressure of
between 70 MPa (1,000 psi) and 125 MPa (18,000 psi) during the mold
filling step until the mold is filled. The disclosed high pressure
structural foam molding process utilizes a molten resin that has a
foaming agent that contains nitrogen or carbon dioxide gas or a
chemical blowing agent. Solid skins are formed against the walls of
the mold, while the core of the part remains structurally foamed.
The class "A" surfaces of the part are solidified to form the outer
surface wall, or skin layer 24.
The disclosed high pressure structural foam molding process
utilizes a molten resin that has a foaming agent that contains
nitrogen or carbon dioxide gas or a chemical blowing agent. Once
the mold is completely filled, the pressure in the mold is reduced
to 7 MPa (1,000 psi) or less to allow the foaming gas or the
foaming agent to expand in the core 30 to fill the walls and
re-pack the part from inside and eliminate sink marks in the skin
layer 24 eliminating Class "A" surface defects. Back pressure is
provided by a pressure generator 44 that provides up to 7 MPa
(1,000 psi) of pressure to the injection molding die while the foam
is formed in the die. The part weight may be reduced by up to 8-20%
because the outer skin is solid and the center of the wall is
foam.
Referring to FIG. 4, a pressure over time graph compares the foam
molding process as disclosed herein to a conventional molding
process. In the illustrated example of the conventional molding
process begins at a pressure of approximately 70 MPa (10,000 psi)
that is reduced over a period of about 5 seconds to approximately
60 MPa (80 psi) and is held until about the 20 second point at
which time the pressure reduced to approximately 52 MPa (7,000 psi)
and is held in a pack and process step until about the 37 second
point in the process.
With continued reference to FIG. 4 the molding process disclosed
herein is described. The process begins by injecting the mixture at
a pressure of approximately 83 MPa. (12,000 psi) The pressure is
reduced over a period of about 10 seconds to approximately 7 MPa
(1,000 psi) and is held at approximately 7 MPa (1,000 psi) for
about 40 seconds until the foam is formed in the die.
Referring to FIG. 5, the step of allowing the foaming agent to
expand is illustrated. The heated mixture expands after filling the
die 42 (shown in FIG. 3) and after the skin layers 24 are formed,
the foamed mixture is formed with a limited amount of back pressure
being provided as the core 30 is formed. The finished dash panel
extension 12 includes the thin outer wall, or skin 24, on the top
26 and bottom 28 surfaces that are separated by the foam core
30.
Referring to FIG. 6, a cross section of a finished part is shown to
include the foam core 30 that is bounded by the skin layers 24. The
skin layers 24 include basalt fibers 48 and mica 50 that are
retained in the skin and oriented in the direction of material flow
during the step of injecting the mixture into the injection molding
die 42 (shown in FIG. 3).
The PET resin may be provided as a blend of virgin and recycled PET
in a ratio of 0:100, 10:90, 25:75, 50:50, 75:25, 90:10, or 100:0
and may be filled with basalt fibers and mica. The basalt fibers
enhance the heat deflection characteristic of the finished product
as shown in the previous example. The mica filler enhances the
ability of the finished part to absorb, or attenuate, sound. Mica
having an aspect ratio of 55:1 such as 200 mesh phlogopite mica
with a mean particle size of 45 .mu.m, an aspect ratio of 80:1 such
as 325 mesh phlogopite mica with a mean particle size of 8 .mu.m,
or an aspect ratio of 90:1 such as 150 mesh phlogopite mica having
a mean particle size of 34 .mu.m may be specified for improved
sound attenuation. The aspect ratio is the ratio of the diameter of
the platelet to the thickness of the platelet.
The basalt fibers may comprise 25% of the composition by weight and
the mica may comprise 10% of the composition by weight.
Alternatively, the basalt fibers may comprise between 10 and 25% of
the composition and the mica may comprise between 5 and 15% of the
composition by total weight.
A coupling agent such as maleic anhydride grafted polypropylene may
be added to increase the bond strength of the mica and basalt
fibers to the base resin for improving impact properties and
stiffness. One example of a coupling agent is maleic anhydride
grafted polypropylene. Other suitable coupling agents may include a
soft E-nBA-GMA like Elvaloy.RTM. PTW from Dupont, an acrylate
copolymer like DuPont.TM. Elvaloy.RTM. AC or a variety of
organosilanes including vinyl silane, Aminosilane or Methacryl
Silanes The coupling agent may comprise 0.5 to 3% by weight, 1 to
2% by weight or 1.5% by weight.
A flow enhancer may be incorporated in the mixture such as
phosphonium tetraborate salt or trihexyl(tetradecyl)phosphonium.
Other types of flow enhancers may include the use of Glycol Ethers
and Ester Solvents. The flow enhancer may comprise 0.5 to 3% by
weight, 1 to 2% by weight or 1.5% by weight.
A foaming agent may be used that contains a nitrogen or carbon
dioxide gas or blowing agents such as isocyanates, hydrazine,
Calcium Carbonate CaCO3 or as an alternative directly introducing a
super critical nitrogen or carbon dioxide fluid by using Mucell.TM.
or similar process. The blowing agent may comprise between 0.5 to
2% by weight, between 0.75 to 1.5% by weight or 1% by weight.
Example 1
In a first example, polyethylene terephthalate (PET) resin is
filled with between 35 and 40% filler material. The resin may be
50% virgin PET and 50% recycled PET and has a melting point of
250.degree. C. The deflection temperature of unfilled PET at 0.46
MPa is 70.degree. C. and at 1.8 MPa is 65.degree. C. at 1.8 MPa.
PET when filled with 20% basalt fibers can obtain a heat deflection
temperature of 250.degree. C. AT 1.8 MPa. If recycled PET is
included, the resin mixture may further comprise a flow
enhancer.
Example 2
In a second example, the mixture by weight includes the following
components, the weight of each component is based on the total
weight of the mixture: 61% copolymer of polypropylene; 25% basalt;
10% mica 1.5% maleic anhydride grafted polypropylene (coupling
agent) 1.2% color masterbatch (colorant); and 1% foaming agent.
When tested using ISO Test Method 527 the elongation at yield was
2.5% and the tensile modulus was 9.2 GPa. ISO test Method 178
resulted in a flex modulus of 7.5 GPa. ISO Test Method 180 resulted
in an Izod impact result of 9.0 Kj/cm. IOS Test Method 1183
resulted in a density of 1.55 gm/cc. ISO test method 75 resulted in
a heat deflection at 260 psi of 220.degree..
Example 3
In a third (prophetic) example, the mixture by weight includes the
following components, the weight of each component is based on the
total weight of the mixture: 81% copolymer of polypropylene; 10%
basalt; 5% mica 1.5% maleic anhydride grafted polypropylene 1.2%
colorant; and 1% foaming agent.
When extrapolated in a simulation, ISO Test Method 527 the
elongation at yield was 3.1% and the tensile modulus was 3.9 GPa.
ISO test Method 178 resulted in a flex modulus of 3.7 GPa. ISO Test
Method 180 resulted in an Izod impact result of 11.0 Kj/cm. IOS
Test Method 1183 resulted in a density of 1.36 gm/cc. ISO test
method 75 resulted in a heat deflection at 260 psi of
190.degree..
Example 4
In a fourth (prophetic) example, the mixture by weight includes the
following components, the weight of each component is based on the
total weight of the mixture: 76% copolymer of polypropylene; 10%
basalt; 10% mica 1.5% maleic anhydride grafted polypropylene 1.2%
colorant; and 1% foaming agent.
When extrapolated in a simulation, ISO Test Method 527 the
elongation at yield was 2.6% and the tensile modulus was 4.1 GPa.
ISO test Method 178 resulted in a flex modulus of 3.8 GPa. ISO Test
Method 180 resulted in an Izod impact result of 9.0 Kj/cm. IOS Test
Method 1183 resulted in a density of 1.4 gm/cc. ISO test method 75
resulted in a heat deflection at 260 psi of 200.degree..
Example 5
In a fifth example, acrylic-styrene-acrylonitrile (ASA) resin is
provided with 35% filler including 25% chopped basalt fibers by
weight and 10% mica by weight having an aspect ratio of 80:1 of the
diameter of the platelet to the thickness of the platelet. ASA is
believed to be amenable to being combined with the same
constituents as listed above in the same proportions by weight.
The embodiments described above are specific examples that do not
describe all possible forms of the disclosure. The features of the
illustrated embodiments may be combined to form further embodiments
of the disclosed concepts. The words used in the specification are
words of description rather than limitation. The scope of the
following claims is broader than the specifically disclosed
embodiments and includes modifications of the illustrated
embodiments.
* * * * *
References