Note: Descriptions are shown in the official language in which they were submitted.
212~07
FIBER GLa8~ CO~PO8ITE
u~nT.TNER AND ~ D OF MARING T~B 8A~E
R~R~~~UND OF ~E INVENTION
This invention relates to panels for lining the interior
surface of an automotive roof. More particularly, the invention
relates to a self-supporting fiber glass composite headliner
panel.
5The interior surface of an automobile roof is commonly
cove~ed or lined with material which presents an attractive
appearance and also acts as a sound absorber. Molded fiber glass
panels and foam liners are examples of such liners. Basically,
these products adequately perform the functions for which they
10were designed, but they are too ~p~n~ive to be used in econ' ~
automobiles. ~co~ ~ automobiles require a liner that is not
only attractive and sound absorbing but one which is less costly.
one of the materials designers consider when confronted with
the need to produce an in~p~n~ive sh~re~ product such as a
15he~l;n~r is wood fibers. Wood fibers are readily available,
inexpensive and can be formed into ~arious shapes by a variety
-of manufacturing techn;ques. Hardboard headliners have been
manufactured from a wood fiber mat formed from an aqueous slurry.
The wood fiber mat is placed in a mold where resins in the wood
20fiber mat enable the mat to be compressed to a higher density and
sh~pe~ under heat and pressure. However, this product is too
heavy; it is difficult to mold; and it has poor acoustical
pLope~Lies.
Other attempts to produce light, low cost hP~lin~rs
25involved forming the he~ nprs from two paperboard facers with
a corrugated paperboard medium sandwiched between the paperboard
facers. While inexpensive, these headliners lack adequate sound
absorption properties and are difficult to form, without
crackinq, into the ~ished shape required for a headliner panel.
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U.S. patent nos. 4,886,696 and 5,057,176, disclose a
corrugated paperboard automotive headliner which solved many of
the problems associated with the previously discussed headliners.
The headliner disclosed in these patents is self-supporting,
inexpensive and exhibits surprisingly good sound absorption
properties. While the headliner of the '696 and the '176 patents
performs very well, the composite headliner of the present
invention is inexpensive and provides another approach to solving
the headliner problems associated with economy vehicles.
~UMM~Y OF T~E INVENTIO~
The self-supporting, composite, fiberglass headliner panel
of the present invention combines the strength of a single faced
corrugated sheet with the sound absorption qualities of fiber
glass insulation. The single faced corrugated sheet forms the
backing for the panel and comprises a vapor impervious, wood
fiber filled polypropylene backing sheet and a corrugated
paperboard medium. A layer of fiber glass insulation is adhered
to the corrugated medium and forms the facing which is exposed
to the interior of the vehicle for appearance and the absorption
of sound.
In the manufacture of the self-~u~uLLing headliner panel,
a coL,u~ated paperboard medium is located on a sheet of wood and
polypropylene fibers and an uncured layer of fiber glass
- insulation is located on the COL' u~dted paperboard medium. The
resulting l inAte is placed in a heated mold. As the l~ ;n~te
is shaped under heat and pressure, the polypropylene fibers in
the backing sheet melt and flow around the wood fibers to cause
the backing sheet to conform to the surface of the mold and to
adhesively bond the corrugated medium to the backing sheet. At
the same time, the resin in the fiber glass insulation cures to
cause the layer of fiber glass insulation to conform to the
surface of the mold and to adhesively bond the fiber glass layer
to the corrugated medium.
The composite fiber glass headliner panel of the present
invention is inexpensive. The he~liner panel is self-supporting
and has greater strength than fiber glass or paperboard headliner
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panels. For example, one headliner panel of the present
invention could be used to line the roof of a van which now uses
three headliner panels to cover the roof.
The single faced corrugated backing sheet gives the
headliner panel sound tr~n! ;ssion loss while the fiber glass
facing layer gives the headliner panel good sound absorption
properties. Since the single faced corrugated backing sheet
provides the strength for the laminate, "pillowed" areas can be
used in the fiber glass facing layer for greater sound absorption
without ~ ing the strength of the panel as is the case
with all fiber glass headliner panels.
In the molding process, the polypropylene fibers in the
backing sheet melt and the uncured phenolic resin in the fiber
glass facing cures to act as the adhesives to bond the laminate
together. Thus, the need to apply separate adhesives to the
layers of the laminate to bond the laminate together is
~l; ;n~ted.
BRIEF D~UTPTION OF TH~ DRAWING8
FIG. 1 is a perspective view of an automotive he~liner
panel of the present invention.
FIG. 2 is an enlarged partial sectional view of the
headliner panel taken along line 2-2 of FIG. 1.
FIG. 3 is a schematic view of the method of forming the
- headliner panel of the present invention.
~r~TPTION OF TH~ PREFERRED ~MRODTM~NT ~-
FIG. 1 shows the self-supporting headliner panel 10 of the
present invention which comprises a single-faced CO~L U~dted
h~rking sheet 12 and a fiber glass facing layer 14. The
headliner panel 10 is sh~pe~ to conform to the interior surface
of an automotive roof with the convex surface of the headliner
being installed adjacent the roof of the vehicle and the concave
surface of the headliner being exposed to the interior of the
veh~cle. The headliner panel may be installed in a vehicle by
any of a variety of methods which generally utilize clips or
other attachment devices. Since the methods of attaching
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212~L~0 7
headliner panels to the roofs of vehicles are well known in the
art and form no part of the present invention, the attachment
devices are not shown.
As best shown in FIG. 2, the self-supporting headliner panel
10 of the present invention is a l~ in~te with a single faced
corrugated backing sheet 12 that is installed in a vehicle
adjacent or against the interior surface of the vehicle roof and
a fiber glass facing layer 14 which is exposed to the interior
of the vehicle. The single faced corrugated backing sheet 12
provides the structural strength of the laminate and the fiber
glass facing layer 14 provides the sound absorbing properties of
the laminate.
The single faced corrugated backing sheet 12 comprises a
vapor impervious, wood fiber filled polypropylene sheet 16 with
a corrugated paperboard medium 18 adhered thereto. The caliper
of the wood fiber filled polypropylene backing sheet 16 is
generally between 18 and 22 points. The preferred composition
of the wood fiber filled polypropylene backing sheet 16 is about
65~ wood fibers and about 35% polypropylene by weight. However,
the composition can range from 60% to 75% wood fibers and from
40% to 25% polypropylene by weight.
The preferred wood pulp fiber is a long, soft bleached
southern pine which has been found to work better than short or
hard wood fibers. The longer fibers function to decrease the
- 2S density of the sheet 16 by creating loft. This causes the
backing sheet 16 to conform more readily to the contour of the
mold surface when the l~ in~te is being molded into the headliner
panel 10. In addition, the longer length, soft bleached,
southern pine fibers improve the tear strength of the h~ck;ng
sheet 16 due to the greater entanglement of the longer fibers
with ~u ,uunding fibers. The long southern pine fibers are
between 50 and 150 microns long and have a diameter of between
20 to 60 microns and preferably between 30 to 50 microns. In
addition to southern pine fibers, other long, soft pine fibers
can also be used in the sheet 16.
In addition to providing structural strength to the
laminate, the wood fiber filled polypropylene backing sheet 16
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2124~07
also functions as a vapor barrier for the headliner panel 10 and
prevents condensation from the metal vehicle roof from
penetrating the headliner. This eliminates the need for a
separate vapor barrier in the laminate and reduces the cost of
the headliner panel.
The corrugated paperboard medium 18 is preferably a C flute
which is 141 mils thick and contains 39 flutes per foot. The
corrugated medium 18 should be at least 30 pounds per 1000 square
feet of medium and can be up to 40 pounds per 1000 square feet
of medium.
The fiber glass facing layer 14 is formed from a fiber glass
insulation blanket having a density of between 4 and 10 pounds
per cubic foot. The fiber glass facing layer 14 generally ranges
in thickness from 1/8 of an inch up to about 1 1/2 inches. Since
the backing sheet 16 and the corrugated medium 18 provide the
structural strength of the panel laminate, portions of the fiber
glass facing layer 14 can be formed at a lower density for better
sound absorption without adversely affecting the strength of the
headliner. These "pillowed" areas pose a problem in molded fiber
glass headliners where the reduction in density of the fiber
glass we~ken~ the panel.
The fiber glass composite headliner panel 10 is formed in
a molding process. FIG. 3 shows a heated press 20 comprising a
male mold ~-h~r 22 and a female mold - h~r 24. Both members
- 25 contain heating units 26 such as electrical heaters or hot water
lines which maintain the male and female non-planer press
surfaces 28 and 30, respectively, at a predetermined molding
temperature.
The molding temperature for this process ranges from 400
degrees to 570 degrees Fahrenheit. The curing time in the press
for the laminate will vary dep~n~ing on the density of the fiber
glass insulation used to form the facing layer 14.
As shown in FIG. 3, the self supporting he~liner panel is
formed by locating the backing sheet 16 in the press. The
backing sheet comprises wood fibers and polypropylene fibers.
The average diameter of the polypropylene fibers is between 1 and
8 microns and preferably between 1 and 4 microns. The average
~ 12 ~
diameter of the wood fibers is between 20 and 60 microns and
preferably between 30 and 50 microns~ The average length of both
the wood and polypropylene fibers is between 50 and 150 microns.
Sheets with larger diameter polypropylene fibers do not work in
this process. When larger diameter polypropylene fibers are used
in the sheet, the fibers migrate to the surface during the sheet
forming process and the sheet does not process properly.
The corrugated paperboard medium 18 is located on the
backing sheet 16 and a layer of uncured fiber glass insulation
14 between 4 and 6 inches thick is located on the corrugated
paperboard medium. The press is then closed as shown in FIG. 3
by bringing the male mold member 22 down into the female mold
member 24. The heat and pressure cause the polypropylene fibers
in the backing sheet 16 to melt and flow around the wood fibers
as the sheet conforms to the configuration of the female mold
surface 30 thereby forming a vapor impervious sheet. The
polypropylene also acts as an adhesive to bond the corrugated
paperboard medium 18 to the backing sheet 16.
At the same time that the backing sheet 16 is being molded
to conform to the surface 30 of the female mold h~r, the fiber
glass insulation facing layer 14 is being cured and conformed to
the surface 28 of the male mold h~r 22. As phenolic resin in
the fiber glass insulation is cured, the resin functions as an
adhesive to bond the fiber glass insulation facing layer 14 to
- 25 the corrugated paperboard medium 13. When the fiber glass
insulation facing layer is cured, the formed he~liner panel 10
is removed from the press 20.
While not shown, the backing sheet 16 and the corrugated
paperboard medium 18 will be normally bonded together in a
conventional heated corrugation -çh;ne prior to being il.LLod~ced
into the press 20.
As shown in FIG. 3, the surface 28 of the male mold member
22 is inclined so that the spacing between the male mold surface
28 and the female mold surface 30 varies when the mold is closed.
Thus, the thickness and density of the fiber glass facing layer
14 varies from one area of headliner to another creating
"pillowed" areas for better sound absorption in selected areas
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~ 2~2~407
of the headliner. Since the single faced corrugated backing
sheet 12 provides the structural strength for the self-supporting
headliner panel, the l'pillowed" areas can be incorporated into
the headliner without adversely affecting the physical properties
of the headliner panel.
