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AUTOMOTIVE CEILING PANEL AND PROCESS FOR MANUFACTURING SAME

Abrégé anglais

ABSTRACT OF THE DISCLOSURE
An automotive ceiling panel and a process for manu-
facturing the same and more particularly, to a process which
reduces the weight of the panel and the man-hours required for
the manufacture thereof and yet results in an improvement in
the quality of the panel. The ceiling panel comprises a laminate
of a first polyethylene foam layer having an aesthetically de-
signed crimp-pattern in its layer surface, a second metal lath
laid under the first polyethylene foam layer, and a third layer
of polyethylene foam laid under the metal lath. The metal lath
is sandwiched between the polyethylene foam layers, with the
crimp-pattern appearing on the top surface of the panel. A
process of manufacturing the automotive ceiling panel comprises
the steps of forming a crimp-pattern in the surface of a first
polyethylene foam layer by a crimp-pattern forming machine,
placing a metal lath between the first and a second polyethylene
foam layer, with the crimp-pattern carrying surface of the first
polyethylene foam layer appearing on the top surface of the first
layer, bodning the thus laid layers together using fusion-bonding
and rolling techniques, and cold-pressing the laminate thus pre-
pared into a desired shape for an automotive ceiling.

Revendications

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows:-
1. An automotive ceiling panel comprising a laminate of:
a first polyethylene foam layer having an aesthetically
designed crimp-pattern in its layer surface,
a second metal lath laid under said first polyethylene
foam layer, and
a third layer of polyethylene foam laid under said
metal lath;
said metal lath being sandwiched between said polyethylene foam
layers, with said crimp pattern appearing on the top surface of
the panel.
2. A process for manufacturing the automotive ceiling
panel, comprising the steps of:
forming a crimp-pattern in the surface of a first
polyethylene foam layer by a crimp-pattern forming
machine;
placing a metal lath between said first and a
second polyethylene foam layer, with the crimp-
pattern carrying surface of said first poly-
ethylene foam layer appearing on the top surface
of said first layer;
bonding the thus laid layers together using
fusion-bonding and rolling techniques; and
cold-pressing the laminate thus prepared into
a desired shape for an automotive ceiling.
3. A process for manufacturing an automotive ceiling
panel as set forth in claim 2, wherein said cold-pressing is
carried out by using upper and lower pressing dies, said upper
die being formed with a protrusion along its peripheral edge

and said lower pressing die being formed with a channel along
its peripheral edge in registration with said protrusion, said
channel being cooperative with said protrusion to secure the
laminate and thus avoid the formation of wrinkles on the sur-
face of said panel during the press-forming step.

Description

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This invention relates to an automotive ceiling panel
and a process for manufacturing the same and more particularly,
to a process which reduces the weight of the panel and the man-
hours required for the manufacture thereof and yet results in an
improvement in the quality of the panel.
The automotive ceiling panel of the prior art consists
of four layers, i.e., from top to bottom, a vinyl chloride layer,
a polyethylene foam layer, a metal lath, and a polyethylene foam
` layer, all of which are bonded together.
, 10 Such automotive ceiling panels suffer from many draw-
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backs either due to manufacturing cost or complexity of the
process for manufacturing the same. Particularly, in the pro-
cess, problems with wrinkles forming on the surface of the panel
during the press-forming process as well as failure of the metal
lath are encountered.
Accordingly, it is an object of the present invention
to provide an automotive ceiling panel and a process for manu-
facturing the same in which the manufacturing cost and man-hours
required for the manufacture of the panel may be significantly
reduced.
, It is another object of the present invention to pro-
vide an automotive ceiling panel and a process for manufacturing
the same wherein wrinkles which may occur during the cold-press -
forming process may be avoided and in addition, wherein a crimp-
' pattern i~ formed in the high-density layer in the top surface
of the panel thus prepared.
According to one aspect of the present invention, there
is provided an automotive ceiling panel which comprises a lami-
nate of a first polyethylene foam layer having an aesthetically
designed crimp-pattern in its layer surface, a second metal lath
laid under the first polyethylene foam layer, and a third layer
of polyethylene foam laid under the metal lath. The metal lath
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is sandwiched between the polyethylene foam layers, with the
crimp-pattern appearing on the top surface of the panel.
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According to another aspect of the present invention,
there is provided a process for manufacturing an automotive
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ceiling panel which includes the steps of forming a crimp-
pattern in the high-density surface of a first polyethylene
foam layer by a crimp-pattern forming machine, placing a metal
lath between the first polyethylene foam layer and a second
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polyethylene foam layer with the crimp-pattern carrying surface
of the first polyethylene foam layer being placed at the top,
bonding the thus laid layers using conventional fusion bonding
and rolling techniques, and cold-pressing the laminate thus
bonded into the desired shape.
In a drawing which illustrates embodiments of the
e present invention:
,!'~ Figure 1 is a partial cross-sectional view of an
automotive ceiling panel according to the
, present invention,
Figure 2 is a view illustrative of an embossing step
`; 20 of the process according to the invention,
Figure 3 is a view illustrative of a fusion-bonding
~- and rolling step of the process according
- to the invention, and
Figure 4 is a view illustrative of a cold-press --
forming step of the process according to
the invention.
Referring to Figure 1, there is shown a partial cross-
sectional view of an automotive ceiling panel which is laminated
according to the process of the invention. Shown at 2 is a first
polyethylene foam layer having an embossed crimp-pattern 1 on its
high density surface~ The pattern provides the aesthetics of
the panel since it ultimately is visible to the user. The first
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polyethylene foam layer has a specific gravity ranging from 0.02
: to 0.1.
- Shown at 3 is a metal lath, and at 4, a second poly-
ethylene foam layer having a specific gravity ranging from 0.02
~, to 0.1. The metal lath 3 is thus sandwiched between the first
and second polyethylene foam layers.
The three layers thus laminated are then fusion-bonded
by a pair of rolls and heaters. The automotive ceiling panel of
the aforesaid arrangement provides the desired rigidity, heat
insulation and noise shielding effect.
,," .
Figure 2 shows an embossing step of the process accord-
D ing to the invention. One surface~of the first polyethylene
foam layer 2 is heated by means of heaters 6, and then the first
layer 2 is embossed by embossing rolls 5,5, to provide a crimp-
pattern 1 thereon.
, Figure 3 shows a bonding and rolling step of the pro-
cess according to the invention. The first polyethylene foam
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layer 2 carrying a crimp-pattern 1 thereon and the second poly-
ethylene foam layer 4 are heated by heaters 7,7 and introduced
between rollers 8,8 with the metal lath 3 being sandwiched there-
between. As a result, the three layers are fusion-bonded to give
a flat laminate or a panel.
Figure 4 shows a cold-press forming step in accordance
with the process of the present invention. There is shown a cold
forming press which includes an upper die 9 and a lower die 10.
The upper die 9 is formed with build-up portion or protrusion 11
along its peripheral edge for holding down the panel during the ~-
press forming, in cooperation with a peripheral channel 12 formed
in the lower die 10. The cooperation of protrusion 11 and channel
12 serves to secure and hold the laminate in place during press
forming and thus eliminates the formation of wrinkles in the
panel during press forming.

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.
, In operation, a panel prepared as outlined above is
cut to the desired dimensions and placed on top of the lower die
10, with the embossed crimp surface of the panel facing upwards.
-~ The upper die 9 is then lowered to form the panel into a desired
shape. In this respect, the edges of the panel are held between
the build-up portion 11 and the channel 12 so as to prevent a
....
wrinkle on the surface of the panel.
As is apparent from the foregoing description of the
~' automotive ceiling panel according to the present invention, a
crimp-pattern is formed in a high density layer in the top sur-
face of a polyethylene foam layer, and the ceiling panel may be
, made of three layers, as opposed to the four layers of a prior
art ceiling panel, so that the man-hours normally required for
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the manufacture of a ceiling panel as well as its weight may be
reduced accordingly. In addition, the dynamic frictional co-
~', efficient of the polyethylene foam layer is smaller than that
of the prior art vinyl chloride skin, resulting in improvements
in the drawability of the panel during the cold-press forming
step, and in elimination of failure or breaking of the metal
lath. Furthermore, since polyethylene provides a solvent-
resisting property, stains on the surface of the polyethylene
foam layer may be wiped off easily.
; Additionally, the prior art ceiling panel with the
vinyl chloride skin suffers from a low bonding force between
the vinyl chloride skin and the polyethylene foam layer, so
that the skin is liable to be stripped off. The ceiling panel
according to the invention is free of such defects.
Furthermore, a ceiling panel according to the inven-
tion provides less spring-back force and higher rigidity, as
compared with those of the prior art ceiling panels. In addi-
tion, ceiling panels in accordance with the present invention
include layers made of a polyethylene foam, thus allowing for
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a change in volume with ease, leading to freedom from winkles on
the surface of the panel, thus improving the yield of panels in
the process.
- At the same time, waste materials from the panels may
be separated with ease into constituent materials, because the
ceiling panel is made of only two kinds of materials, i.e., a
polyethylene foam and a metal lath.
The foregoing description and embodiments are pre-
sented herein for illustrative purposes only, and are not
~, 10 intended to unduly limit the scope of the invention.
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