Note: Descriptions are shown in the official language in which they were submitted.
2.FUG.2002 14:22 RN'~IRLTSKRNZ'~EI RIEDER & P1RTNER NR.24S S.2i'_2
WO 00/34943 PCT/EP99/09509
Multi-la er insulating elea~ient
The invention relates in the first instance to
a multi-layer insulating element with a layer of
nonwoven material and a layer of cellular material,
which are provided in layers arranged one on top of the
other.
Insulating elements of this type are already
known in various forms. However, these are not
satisfactory in every respect with regard to various
requirements, which are generally to be accomplished in
combination. Anong these requirements are high sound
absorption and/or sound insulation, which in particular
allows curve characteristics with regard to a sound
absorption curve and a sound-insulation measuring curve
in a frequency band between 10 and 20, 000 Hz. Further
requirements are, a high 'thermal insulation and a low
level of liquid water formation when there are great
tempera~ure gradvent~~ and great atmospheric humidity
grad=ents, iy at all possible also combined with
comparatively low weights per unit area and good
suitability for handling as a fitted element.
The invention is therefore concerned with the
technical problems involved in specifying an insulating
element of the type in question which is distinguished
by meeting one or more of the aforementioned
requirements t~ a high degree o~ satisfaction.
These technical problems are initially and
essentia'.:ly solved by the subject-matter of Claim 1,
based on the idea that the layer of cellular material
consists of non-flats, three-dimensionally structured
polyimide foam. As a result of this configuration, a
layer of the insulating element which is distinguished
by low weight with a comparatively large volume is
created. This layer of polyimide foam is structured in i
such a way that, when. viewed in the extent of its
plane, .t extends in a Third dimension, i.e. toward the
1 Translator's Note: optionally "non-planar" or "undulating".
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layer of nonwoven material.arranged above this layer or
away from the layer of nonwoven material arranged below
this layer, for example by means of elevations in
certain. regions. These may be further formed for
example by wave-like or pit-like elevations or
formations. In this respect, a mould-foamed polyimide
foam can also be used. The non-flat structure of the
polyimide foam, formed on an upper side, may also be
reproduced in negative on the underside, so that
according to the invention both surfaces are non-flat,
three-dimensionally structured, to increase the overall
surface area of the layer of cellular material.
Furthermore, the invention also relates to a multi-
layer insulating element with two layers of cellular
material which are provided in layers arranged one on
too of tl:e other, the invention being based here on the
idea that one layer of cellular material consists of
non-flat, three-aimensionayly structured polyimide
oam. Irrespective o' the ~'~ayered structure, which is
c0 a matter of choice, that is a layer o.nonwoven
material with a layer of cellular material or two
layers of cellular material, in a preferred
configuration of the subject-matter of the invention it
is provided that the layer of cellular material
consists of a cut foam. It is particularly preferred
in this respect that the layer of cellular material
runs in a zigzag fo~m, the path it follows extending in
the plane of the layer of cellular material.
Accordingly, the elevations formed by the zigzag form
extend in tre direction of the layer arranged above it
and/or below it. As a result, the layer (layer of
nonwoven material or further layer of cellular
n,ater~~al) arranged above and/or below the layer of
cellular mater_al formed according to the invention is
spaced from the ':.ayer of polyimide foam, cavities
approximately v-shaped in cross section being formed in
the interstices of the zigzag form. It proves to be
particularly advantageous in this respect for a desired
sound absorption behaviour to be set by means of the
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thickness ard/er the angular path of the zigzag webs
relative to the perpendicular. As a consequence of
this configuration, the scund absorption behaviour can
be pre-set dur,_r.g the production of the layer of
ce'_lular material according to the invention by
choosing the material thickness and/or the path
followed by the zigzag structure. In a further
embodiment of the subject-matter of the invention, it
is provided that the layer of cellular material is
covered on the uppsr side and underside by a layer of
nonwoven material_ This may in each case be a needled.
condensed or mechanically compacted nonwoven.
urthermore, melofil fibres may also be used here in a
proportion of 10-'70~, preferably 50~. It is also
conceivable to form the upper layer of nonwoven
:~.aterial, preferably facing the noise source, as a
r~.elt-blown nonwoven and to form the lower layer as a
thermally bonded volume r.onwoven. Furthermore, there
is also the possib~.'~,yt~r or using a blend of melamine
2C fibres and basofl fibres for producing a three-
dimensional framework. In addition, with an
arrangement of at least two layers of cellular material
lying one on top of the other, there is (the
possibility] of forming each layer of cellular material
prom polyimide, the non-flat, three-dimensionally
structured, preferably zigzag-structured layer of
polyimide foam being covered on the upper side and
underside with a M at layer of polyimide foam that is
relatively thin in relation to the layer of structured
3C cellular material. In addition, two layers of cellular
material :nay also be provided, with a layer of nonwoven
material provided between them. Preferred ir_ this
respect is a configuration in which both layers of
cellular material are designed in a way corresponding
3~ to the configurations described above in a non-flat,
three-dimensionally structured manner as layers of
polvimide foam and the interposed layer of nonwoven
material is a melt-blown nonwoven. Tre layers of the
insulating element a.re, furthermore, sheathed by a
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Film. Tn particular, this sheathing film comprises two
=~llm layers, which are further preferred to be outer
layers. These fil~,; layers sheath the layers of
insulation arranged one on top of the other to form a
compact, mufti-layer insulating element. The film
layers may also be additionally provided as
intermediate layers. Tt is further preferred for the
cuter films to be edge-welded, but all or some of the
layers of nonwoven and/or cellular material may be
integrated into the weld, for instance by a layer of
nonwoven and/or cellular material edge-compressed to
virtually nethirg. Such edge compression may also be
used for shaping the component. Fastening elements may
also be integrated into such a weld. The joining
together of the outer films is suitably provided in
th_s case by the complete composite structure being
:geld together just by the edge-welded films and
possibly layers ef nonwoven and/or cellular material.
too adhesive bonding, l~aminaticn or the like ef
2~ individual layers is required and is preferably also
not provided. The payers arQ simply laid one on top of
'he ether - at least outside the edge region. This
produces as it were a cushion with a sheath formed by
the outer films. Partial compressed portions, brought
about by welding operations, in particular in the edge
region, can play a part in accommodating fastening
elements and/or reinforcements of the component. The
plurality of layers !layers ef nonwoven and/or cellular
material) lead to a kind of swollen filling. It is
3C also of signirica:~ce for the sub=ect-matter that the
formation of liqu~ld water in the component is reduced.
The films used, both tl~_e outer films and possibly also
intermediate films, have different water permeability,
it being preferred for water-vapour-permeable membrane
films to be used. Preferably used are also films which
have direction-active water vapour permeabilities.
Films which have moisture-dependent and/or temperature-
dependent water vapour permeabilities may also be used.
FLrthermore, these films may also be fibre-reinforced,
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=t being further preferred in this respect for these
fibres to be provided on the inside of the film.
The invention is~ further explained in mere
detail be'~ow w;th reference to the attached drawing,
w~:_ch however merely represents one exemplary
e~.bodiment and in which:
Figure 1 shows a par~ially sectioned
perspective representation of a mufti-layer insulating
element according to the invention;
1C Figure 2 shows a greatly enlarged
representation o' the section along the line II-II in
Figure i.
With reference to Figure 1, an insulating
element 1 which comprises a lower outer film 2 and an
upper outer film 3 and three middle layers 4, 5 and 6
is represented.
:he layers of nonwoven material 4 and 6, of a
flat form, are formed from identical or non-identical
nonwoven material. The fibres of the nonwoven material
2C consist of a polymer; such as for example PPS or a
blend of PPS and copolyester and other organic or
inorganic fibres, the weights per unit area of the
layers of nonwoven material 4 and 6 lying between 50
and 800 g/m2. Moreover, the upper layer of nonwoven
~.aterial 6, preferably facing a noise source, may
consist of a melt-blown nonwoven and the lower layer of
nonwoven material 4 may consist of a thermally bonded
volume nonwoven and/or a layer of cellular material.
The fibres are thermoplastic and inherently
f'_ame-retardant. The granules from which the nonwoven
fibres are obtained have a specific melt viscosity.
The nonwovens are also resistant to hydrolysis.
Mcreover, they are acoustically absorbent and
;nsulating. yn addition, they have a thermally
,insulating effect. They may also be intumescer:t in
order to influence the fire behaviour (favourably).
The middle layer 5 is designed as a layer of
cellular material, in particular as a layer of
polyimide foam wzich, as can be seen in particular from
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the sectiona= representa~ion in Figure 2, is non-flat,
~:zree-dimensionally structured. In fact, the design is
chosen such that the layer.of cellular material runs in
a zigzag form in the extent of its plane. The choice
o' a polyimide foam creates a very lightweight middle
~.ayer with a comparatively large volume for the
Formation of the ,:.nsulating element 1.
The layer of cellular material consists o~ a
cut polyimide foam, the thickness and/or angular path
of the zigzag webs 7 relative to the perpendicular
a_lowirg a desired sound absorption behaviour to be
set. ~n the exemplary embodiment shown, a material
thickness d of approximately 8 mm has been chosen, with
a total height h of the zigzag-shaped layer of cellular
material 5 of approximately 24 mm. Consequently, a
ratio of material thickness d to layer height h of
approximately 1 . 3 has been set. A further preferred
material thickness d is 35 mm, with a height h of 60
m~~. ~_'his gives a ratio of, 1 . 1.7.
Furthermore, an angle alpha of the webs 7
relative to the perpendicular of 45-60°, for example 55°
is chosen.
he thicknesses of the layers of nonwoven
materia'; 4 and 6 are - in the non-compressed state
approximately one third to one tenth of the thickness
of the middle layer (layer of cellular material 5). The
thicknesses of the layers of nonwoven material 4 and 6,
seen i:~ absolute terms, lie in the range from 0.5 to 5
rte.
The a.:ranaerr.ent of the individual layers 4 to 6
one on top of the other has the effect of producing V-
shaped cavities 3, covered by the respectively assigned
layer of nonwcven material 4 or 6, in the region of the
interstices formed by the zigzag form of the middle
layer of cellular mat erial 5. Furthermore, this rnay
have the result that each layer of nonwoven material 4,
6 has a slightly corrugated structure in the extent of
~~ts plane, according to the cross-sectional
representation ir. F~~.gure 2; it is accordingly not
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stretched taut over the middle layer of cellular
material 5.
The film layers 2 and 3 are fibre-reinforced
films of very small thickness, The thickness lies
be~ween 10 and 15 Vim. preferably around 20 Eun. The
density lies around approximately 0.9 to 1.4 g/cm'.
The films are likewise thermoplastic and resistant to
hydrolysis. In particular, they also have water-vapour
permeabilities matching one another.
In terms of material, inherently flame-
retardant polymers may be concerned. As fibres, glass
fibres, but also melamine resin fibres, may be
lamira~ed on for example. In the exemplary embodiment
represented, only the lower outer film layer 2 is
fibre-reinfo:Yced, the fibres 9 being provided on the
i.~.side ef this film 2. .he fibres 9 are indicated in
Figure 1 by a arid on the lower outer layer of film 2.
In the cross-sectional representation according to
Figure 2, the criss-cross arrangement of the fibres 9
is represented on an exaggerated scale.
It is preferred for the fibres 9 to be provided
only on one side of the film. The grid lies between
approxima:ely i and 5 mm. Fibres respectively running
transversely in relation to one another are provided.
The outer film layers 2, 3 are edge-welded, it
also being conceivable to taJce the exemplary embodiment
represented a stage further and integrate all or some
of the layers of nonwoven and/or cellular material 4 to
E into the weld 10, this bei:~g accomplished for
3~ instance by an edge compression of the layers of
noawoven and/or cellular material 9 to 6 going to
virtually noth,'~ng.
T:ze edge compression may be used for shaping
the component. Fastening elements may also be
integrated into such a weld 10.
.he cor.:plete composite struc*~ure is held
together just by the edge-bonded or edge-welded films
2, 3, possibly with the layers of nonwoven and/or
cellular material 4 to 6 being incorporated.
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The layers 4 to E are simply laid one on top of
the other - at least cutside the edge region. This
produces as it were a cushion with a sheath formed by
tce outer films 2, 3. '
A';1 features disclosed are material to the
~.~ventien. The full content of the disclosure of the
associated/attached priority documents (copy of the
prior application) is hereby incorporated in the
disclosure of the application, also ;or the purpose of
"~C including features of these documents in claims of the
present application.
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