Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1327~7~
Method for discharging a foamed material mixture, more
particularly a -thermal insulating material, by means of
a mixing head for at least two reactive compounding in-
gredients in the low pressure process, mixing head for
-
performing the method and thermal insulating material
produced according to the method
Scope of application
The me-thod, the appropriate mixing head and also the thus
fabricated insulating material can be employed wherever insu-
lating material is produced and employed with which it is in-
tended to provide larger roof areas in order to form an insu-
lating and sealing layer.
The present invention relates to a method of discharging a
mixture of foamed material, more particularly for a thermal ,
insulating material, by means of a mixing head for at least
two reactive ~ n~ngredients in the low pressure pro-
cess, consisting of a tube, inside which an agitator rotates
at high speed, a mixing head for performing the method and
an insulating material fabricated according to the method.
State of the art
Mixing heads for polyurethane mixtures of foamed materials
produced in the low pressure process are known. In order to
distribute the material with the aid of a mixing head onto
a substrate passed through underneath the mixing head, the
most widely varying methods and means are employed which are
subject to a great many shortcomings. Due to the high visco-
sity of the Foamed material mixture, not even the reciprocal
travel of the mixing head transversally to the direction of
course suffices for achieving the desired run of the foamed
material mixture. By way of example, fish tail-shaped dis-
charge nozzles are used. Also employed are srrlall bore -tubes,
in which case the mixture is discharged with the aid of
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i32787~
2 23589-124
compres~ed air. All these forms of dischargin~ the mixture of
~oamed materlals, subse~uent to the mixin~ operation, call for a
substantial effort and do not result ln the desirad success or
are, as the discharge ef~ected by compres~ed alr, a hazard to
health.
The present invention seeks to provlde a method of the
kind stated above and a device ~or thls, in which these
disadvantages no longer exist and with the aid o~ which the
dischar~e of foamed materials can be effected without fluctuations
in quality, without interruptions due to arislng preparation ~ime
and in a manner adaptable to all requirements.
For solving this technical problem, a method of the kind
stated in the beginning i5 proposed, ln accordance wlth which the
mixture ready for reaction is discharged by centrlfugal force and
di~tributed onto a substrate~ so as to fully react and ioam
~hereon.
~ The tnventlon therefore provides a method for delivering
a foamable mixture from a mixing head for mixing at least two
reactive components in a low-pressure method, which ~ixin~ head
comprises a tu~e in which an a~itator rotates at high ~peed and
from which the mlxture ready ~or reaction is delivered by gravity
and distributed onto a substrate to react completely thereupon and
to foam ~hereupon, which method comprises discharglng ~he mixture
by centrlfugal force as well a~ gravi~y ~rom the mixing head, and
wherein only one (A) o~ ~he two reactive componen~s, whlch one
reactive component (A~ comprises materials which do not react on
their own, ls introduced in~o a space within said mixing head
located in ~he viclnity of an outer bearing o~ a floatlny sha~
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327g75
2a 23589-124
upon which said agita~or i5 mounted and i~ then conveyed by
centrifugal force to another location in thr mixing head at which
other location reactive component (A) is intermixed with the other
(B) of said two reactive component~ thereby preven~ing premature
reaction of components (A) and (B) in the vicinity o~ the bearing
and protecting said bearing against contamination, heat or damage
by said lnterreacting components.
The method proposed renders a uniform distrlbution of
the foamed materlals mixture on ~he substrate possible, even ~hen
the mixture of foamed material is highly viscous and at the lowest
throughput in the simplest manner whlle avoidlng the disadvantages
~tated.
The invention further provides a mixlng head comprising
a casing-like mixing tube provided ~ith a dlscharge aperture at
one end and a lid-like closing member at the other end, said
closing member having a bearing disposed thereln, said bearin~ :
floatably supporting a drive shaft capable of being driven by
driving means, sald drive shaft having mounted thereon an agitator
body extending along the inside length of the mixing tube to the
area of said discharge aperture, ~aid agitator body being formed
so as to provide an interspace between the agitator body and the
closing member and to provide a mixing chamber between sald mixing
tube inner wall and said agitator body, a first feed channel
terminating in said interspace and a ~econd feed channel
terminating in said mixing chamber.
An appropriate device is ~haracterized in ~hat ~he
mixlng head is axranged within a machine frame, in that the mlxing
head consists of a casing-like mixing tube which, at its upper end
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1327~7~
2b 23589-124
located oppo~ite its lower end in which the discharge aperture is
constructed, is provided with a cover-like sealing body, in that a
bearing is disposed within the sealiag body,
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in which a shaft driveable by a drive means is floatingly
supported, upon which an agitator body extending as far as
into the area of the discharge aperture is mounted and which
shaft is constructed so as to extend righ-t through the entire
mixing tube, in which, underneath the bearing, while forming
a gap-like interspace, the cylinder-like-configured agitator
body is mounted on the shaft, in that the sealing body, a
first feeder channel terminating in the interspace is construc-
ted, and in that, in the mixing tube, a second feeder channel
terminating in a mixing space constructed between the mixing
tube inner wall and the agitator surface is constructed.
If, for instance, larger or smaller widths of the foamed mate-
rial strand are to be fabricated on a laminating machine,then
this can be achieved by the vertical adjustment o-f the mixing
head, in which case the cone of the mixture to be applied,
formed by the centrifugal force, accordingly covers a larger
or a smaller area.
It is also possible to achieve a different thickness of the
foamed material coating transversally to the direction of
travel, as e.g. is necessary for the production of sloping
panels, by inclination by a few degrees from the vertical and
a slight displacement in the horizontal of the mixing head.
If larger widths of application become necessary ~e.g. in ex-
cess of 1000 mm), -then it is possible to dispose two mixing
heads side by side without allowing the mixing head to oscil-
late transversally to the direction of travel of the subs-trate.
By conveying the one compounding ingredient of the foamed ma-
terial with does not react with itself into the proximity of
the outer bearing of the mixing head and the shaft by centri-
fuging in the mixing space, so as to permit it only there to
come into contact with the compounding ingredient wi-th which
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the reaction takes place, a contamination of the bearing
is avoided and the entire mixing head is kept operable for
a continuous operation.
The casing grooves of the agitator which interrupt the screw
channels and bring about a subsequent mixing are expediently
not to be constructed so as to reach the end of the agitator.
It is avoided thereby that, when the conveyor screw channels
are not filled completely due to a high speed or a lower ma-
terial throughput, mixed material about to come to reaction
or air reachesthe lower portion of the agitator and a contami-
nation is precluded here as well.
~r,'c~
D Preferred further development of the ~e are characterized
in the Claims 4 to 13. With such a device it is possible to
provide a thermal insulating material to be used as insula-
ting and sealing layer for roof areas which makes it possible
to simultaneously cover larger areas of several square meters,
the material consisting of strips of insulating material bon-
ded or laminated onto a substrate.
It is known in the case of flat roofs, especially in the
case of so-called non-insulated roofs, to apply the roof sea-
ling in several layers onto the insulation. The manufacturers
of insulating material have tried to simplify this multiple-
layer application in that insulating elements having the nor-
mal dimension of 1 m x 0.5 m were provided with a single sea-
ling layer with an overlap projecting on two sides to be bon-
ded onto already laid material consisting of already applied
insulating elements. It was intended to thereby simplify the
entire roofing operation and to have the insulating material
protected against atmospheric influences and exposure imme-
diately following the laying. It was still necessary then to
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apply the actual sealing layers (at least one) because, due
to the application of the elements, overlaps were produced
which were too short, which gave rise to the fear of a pene-
tration of humidity from the outside.
For the sake of a further simplification and for the sake of
a faster sequence of operations, web rolls were produced that
consisted of a correspondingly wide sealing web having a length
of up to 10 m, which were bonded onto the strips of foamed
material, which made it possible to roll the same up so as
to form webs of up to 10 m in length. These web rolls have
a width of up to 1 m and, with a length of 5 m, cover a roof
area of 5 m2 in one operation. 5 m was the required minimum
length in order to avoid too shortoverlaps of the elements.
These web rolls made it possible for the strips of insulating
material to be rolled up to form a larger unit for covering
larger areas. Normal bituminous roofing webs are employed in
this case as sealing webs. However, when unrolled, the same
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had buckling creases in the carrier web so that there was
good cause to be afraid oF leaks in the finished flat roof.
That is why, additionally, several, but at leas-t one additi-
onal roofing web has to be applied.
Even today, when flat roofs having a slope of 3% or more
are invol;ved, the laying of at least two sealing layers on
one thermal insulation layer is necessary. If the slope is
less than 3% or even zero, three sealing webs or bituminous
sheets on the thermal insulation layer are regarded as being
in keeping with a workmanlike finish. Even the, today, very
highly developed plastic sheets that are admitted in single
layers even on roofs having a zero slope, require as a gua-
rantee on a thermal insulation layer, one additional substrate
web for the protection of the laid sheeting at the joints of
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the thermal insulation against damage and against the migra-
tion of e.g. plasticizers from the sheet sealing. However,
the carrier web located on a web roll, irrespective of the
type, is recognized as a protection of the sheet.
A further signiFicant disadvantage in the multple-layer roof
sealing is the feared bubble formation on the flat roof. This
is caused by non-bonded points between the sealing layers.
The slightest inclusion of moisture when superposing the sea-
ling layers or placing them onto the thermal insulating ma-
terial, results in non-bonded points and, thereby, in the
formation of bubbles or hlisters.
The bubble formation is often put down to the apparently ari-
sing steam pressure, e.g.due to solar irradiation. However,
a steam pressure above atmospheric can only arise at 100C
and more. But the bubble formation in coating layers is only
possible by the volume enlargement of the entrapped air at
the non-bonded points according to the law of Gay-Lussac.
According to this law, the air volumes~behave like the abso-
lute temperatures. That is why a distension of the air bet-
ween the individual sealing layers is unavoidable when the
connection between the individual sealing layers by relevant
bonding or welding is not established in such a way that se-
veral layers become one and a perfect connection comes about.
But this is quite impossible. Matters have improved due the
employment of welding webs, in which case the two joined webs
are fused together. The bubble formation can thus be avoided
only when the layers or sealing layers laid on top of each
other are joined so as to form one whole.
In addition, a further requlrement results today. In the case
of flat roofs, an ever-increasing demand exists, be it in
new buildings or in redevelopment of old ones, that no water
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be left standing on the roof after a rainfall. Consequently,
more and more sloping roofs are produced.
This is done in a conventional manner, in new buildings in
many cases by the application of a sloping coating, either
in heavy concrete or by a light-weight concrete. ~ith this,
the slope is provided and no further consideration is requi-
red when applying the thermal insulating material and the
sealing.
If this is not the case, then the thermal insulating material ~;
is mostly supplied in wedge shape and this very largely in
polystyrene. Various demands are made on the slope, in par-
ticular of from 1% to 3%. This is mostly done according to
previously produced drawings in which the entire slope is
then produced at the works in any form whatever, either by
cutting or by the construction of individual pieces. It
would therefore be desirable to provide a thermal insulating
material which, due to a web-like construction, enables lar-
ger surface elements of the material to be manufacture in
one operation and to cover larger areas of several square
meters all at once.
It is desirable to provide a thermal insulating material
and sealing layer for roof areas which can be employed as
the sole roofing element for the roof areas, that can be laid
on larger areas in one operation and which can also be used
for the construction of a roof slope without the previous
application of a slope piece, in which the disadvantages of
the known solution, such as the trimming waste or the ne-
cessity of individual construction or the formation of buck-
ling creases and the bubble formation are avoidable.
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Above all it is possible with the method and the device to
provide a thermal insulating material as an insulating and
sealing layer in that the strips of insulating material are
laminated onto a suitable sheet web as a sealing layer in
such a way that the thermal insulating material is construc-
ted as a thermal insulating and sealing layer so that, when
it is laid, no need exists for applying a further sealing
layer and in that the strips of insulating material possess
a rectangular or cuneiform cross-section.
By preference, provision is made in this case for the angle
of inclination of the wedge shape transversally to the longi-
tudinal direction of the web rollto correspond ,to a gradient
of 1%,2% or 3%.
With such a thermal insulating material it is possible to
provide a roof area with the requisite thermal insulation
and sealing layer without it being necessary for an additio-
nal sealing web having to be applied. It is possible to
achieve quite a decisive saving in both labour and material
thereby, while at the same time the quality of the roofing
improves since, due to the reduction in the craftsmen's ac-
tivities, a reduction in the possibility of errors is achie-
ved. ~ ;
According to a preferred embodiment, provision is made in
this case for the laminating material to consist of a plastic
sheet while, according to another preferred embodiment, the
laminating material consists of a metal foil. The essential
thing is in this case that it is ensured by such laminating
materials that the thermal insulating material is applied to
the roof area in such a way that an appropriate thermal in-
sulation is produced, on which, at the same time, a sealing
layer is disposed which is connectable without difficulty
1~27875
within the overlap areas so that the insulating material is
protected against atmospheric influences after laying. In
this case the insulating material may, according to a prefer-
red embodiment, consist of polyurethane strips, while accor-
ding to another preferred embodiment, provision has been made
for foamed polystyrene particles or extruded polystyrene to
be used as insulating material. This construction of the
strips of insulating material in the form of hard foamed ma-
terial bodies results in an optimal thermal insulation> in
which case provision is preferably made for the insulating
material to be fabricated and/or applied in such a way that
the strips of insulating material, in the laid state, are lo-
cated side by side without any gaps therebetween.
In this case provision may be made for the insulating material
to be provided with diffusion channels on its surface located
opposite the lamination. These may be constructed in that,
on the surface located opposite the lamination, projections
are provided in regular arrangement which possess a spherical,
a rib-like, a frusto-conical configuration or some other geo-
metrical shape;
In order to increase the inherent stability of the thermal
insulating material, especially -to satisfy the most exacting
requirements, provision may preferably be made for the insu-
lating material and/or the laminating material to be provided
with a stabilizing or reinforcing fabric.
Advantageous and expedient embodiments of the invention are
characterized in the subclaims.
Brief description of the drawings
Embodiments of the invention are explained below with the
aid of the drawings. Thus,
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Figure 1 shows, in a vertical section, a diagrammatical re-
presentation of a mixing head,
Figure 2 shows, in a diagramrnatical representation, -the mixing
head according to the Figure 1 wjth a drive means wi-
thin an indicated machine frame with an indicated
discharge of foamed material,
Figure 3 shows the assembly according to Figure 2 with the
laterally displaced mixing head swivelled out of
the vertical,
Figure 4 shows, in a view from below, a section of a thermal
insulating material,
Figure 5 shows, in a vertical section in the direction of
Line V-V in Figure 4, the thermal insulating ma-
terial, and
Figure 6 shows the thermal insulating material in the side-
by-side arrangement projected for a flat roof for
forming a slope.
Detailed descrlption of the invention and the best way of
.
performing the invention.
In the Figures 1 to 3, a mixing head is depicted for dischar-
ging a mixture of foamed material consisting of compounding
ingredients A and B not shown in the drawing. Such a mixing
head is mounted within a machine frame 11 and is driven by
a driving means 12, while the compounding ingredients ~ and
B are supplied via feeder lines which are not shown.
The mixing head 10 consists of a mixing tube 13 which forms
the discharge aperture 15 at its lower end 14, while the up-
per end 16 is closed with the sealing body, to which the mi-
xing tube 13 is secured.
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Within the area of the discharge aperture 15, the mixing
tube 13 is provided with a chamfer 15a which imparts a spe-
cific discharge cone K to the foamed material consisting
of the mixed compounding ingredients A and B.
Within the sealing body 17 which is secured in a torsionally
resistant manner to the drive means 12, a bearing 18 is dis-
posed in which a floating shaft 19 is supported. Underneath
the bearing 18, the shaft 19 carries the agitator body 20
while the shaft 19 and the agitator body 20 extend as far as
into the area of the discharge aperture 15 of the mixing tube
13. In this case, the agitator body 20 is provided with a
longitudinal drilled hole 120 with which it is mounted on
the shaf-t 19. The shaft 19 is in this case provided with a
shoulder 19a, while the longitudinal drilled hole 120 is
provided with a step 20a in such a way that the agi-tator bo-
dy 20 can be pushed onto the shaft 19 up to the limiting
stop formed by the shoulder 19a and the step 20a.
The agitator body itseif which is constructed in the form
of a cylinder has two sections 21,22, the upper section 21
being provided with mandrels 23 disposed on the surface 20b
of the agitator body 20 and possesses e.g. a frusto-cylindri-
cal shape, while the second section 22 is constructed as a
conveyor screw 24 for conveying the material A,B through
the screw channels 25 of the conveyor screw 24.
Between the disk-shaped upper terminal surface 121 of the
agitating body 20 which is provided with a, in the longitudi-
nal direction L of the shaf-t, projecting, rotating outer rim
12ia, and the oppositely arranged sealing body 17 supporting
the bearing 18, a gap-like interspace 26 is constructed, in
which, a first feeder channel terminating within the area
of the gap-like interspace 26 and/or the rotating rim 121a
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delimiting the latter is constructed in the sealing body 17,
-through which the compounding ingredient A `can be supplied
to this area. Underneath the rotating rim 121a, on the surface
20b of the agitator body 20, before the beginning of the sec-
tion 21 which bears the mandrels, a mandrel-free area 21a is
constructed which has a distance from the inner wall 13a of
the mixing tube 13 predetermined by the height of the mandrels
23 and which forms a first mixing space 27. Into the same,
due to the centrifugal force, the compounding ingredient A
charged into the gap-like interspace 26 is transferred. At the
same time, a second feeder channel 29 terminates within the
area of the mixing space 27 on the inner wall 13a of the mi-
xing tube 13 for supplying the compounding ingredient ~. That
is why the compounding ingredients A and B are mixed within
the mixing space 27, the actual mixing being brought about by
the mandrels 23. Since the compounding ingredients A and B
are supplied in a pressurized state via the feeder channels
28,29, the compound ingredient mixture produced in mixing
space 27 and mixed thoroughly by the mandrels 23 is conveyed
within the area of the conveyor screw 24 and received by the
screw channels 25.
In adaptation to the various factors and influence values as
well as to the compounding ingredients A and B, the spatial
size of the gap-like interspace can be adjusted or altered
in that one or more disks 30 having the same or varying thicl<-
ness can be pushed onto the shaft 19 and brought up -to the
shoulder 19a before the agitating body 20 is mounted and
screwed tight by means of the nut 31 of shaft 19. By the
step 20a coming to abu-t against the disks 30, a longitudinal
displacement of the agitator body is achieved, so that the
size of the gap-like interspace 26 adjusts itself correspon-
dingly enlarged.
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A number of the screw channels 25 of the conveyor screw 24
are connected by interruptions 132 in the screw 24 so that
one or severalconnections extending in the longitudinal di-
rection L of the shaft between the screw channels 25 of the
conveyor screw 24 result. These may also be constructed in
the form of casing grooves 32. In this case, provision is
also made for the screw channels 25, within the area of the
discharge aperture 15, not to be connected by interruptions
132 or by casing grooves 32.
On its outer wall 13b, the mixing tube 13 is, within the dis-
charge aperture area 15, provided with a ring that embraces
the mixing tube 13 as a wiper 33. The wiper 33 is displaceably
mounted on the mixing tube 13 or on the outer wall 13b of the
mixing tube 13 in the longitudinal direction L of the shaft,
while in the drawing, at I., a working position of the wiper
33, and at II., a rest position of the wiper 33 is depicted.
As shown in the Figure 2, the mixed and reacting compounding
ingredients A and B of the foamed material mixture are dis-
charged by the interaction of the agitator 20, the centrifu-
gal forces arising and the chamfer 15a into a discharge cone
K. A discharge results hereby of the material located or
moved underneath the mixing head 10, it being also possible
for the chamfer 15a to be provided with a radius so that the
issuing material forms a steeper dispersion cone K. The ap-
proximately rectangular foam discharge is indicated wi-th 34,
which resul-ts when the mixing head 10 assumes the position
depicted in the Figure 2. when the mixing head, as is shown
in the Figure 3, is swivelled out in the longitudinal direc-
tion of the shaft through an angle with respect to the ver-
tical and is laterally displaced, a rising foam 134 results
that possesses a gradient St, as is also indicated in the
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Figure 3. It is hereby possible to construct the foamed mate-
rials and particularly strips of insulating material which
possess a cuneiform cross-section
The mixing head described in the foregoing which, in principle,
constitutes the device for carrying out the novel method, is
not restricted to the embodiments described in the foregoing
and depicted in the drawings. Changes in the type of the mi-
xing members on the surface of the agitator as well as in the
construction of the discharge aperture come under the scope
of the invention just like another type of adjustment device
when the fundamental teaching is realized, which consists in
that the compounding ingredients A and B are first of all sup-
plied separately to the mixing head and mixed within a space
immune to contaminations.
In the Figures 4 -to 6, an accordingly fabricated thermal insu-
lating material is identified with 100, which consists of the
sheet web 150 as sealing layer and the strips of insulating
material 140 placed thereupon as insulating material 40. In
this case, the sheet web 150, in comparison with the strips
of insulating material 140, are provided with projecting ed-
ges which serve as overlap sections 51,52 and which are dis-
posed on a longitudinal and a transversal edge, respectively.
In a side-by-side arrangement of the thermal insulating mate-
rial web (depicted in Figure 6), relevant overlap sections 51,
52 can be placed upon the already laid insulation webs and be
welded to each other so that a secure protection against at-
mospheric influences is provided. The strips of insulating
material 140 consist in this case of the insulating material
40, for which polyurethane or polystyrene can be selected.
The employment of glass fiber and rock wool strips is also
possible. Provision may be made in this case for the insula-
ting material 40 to be provided with a stabilizing fabric.
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In addition, on the side facing away from the sheet web 150
of the strips of insulating material 140, spherical projec-
tions 41 in regular disposition are provided for the construc-
tion of diffusion channels 42. These are cons-tructed in the
form of flat prominences, while it is possible to also provide
any other suitable configuration and disposition by means of
which it is ensured that, between the roof to be covered and
the insulating material 100, a dehumification zone is created,
in which a partial pressure ratio then results which, on ac-
count of its relationship to the partial pressure ratio of the
ambient atmosphere, leads to an evacuation of the humidi-ty from
the building surface.
By means of -the depicted assembly, particularly wide and regu-
lar steam expansion paths are provided which ensure a certain
dehumification. In this case, a metal foil 60 is bonded onto
the insulating material 40 on the surface located opposite the
single-layer sealing layer lamination 50, while the lamination
ma-terial is constructed in the form of plastic sheet, metal
foil, welding web or bituminous sealing web.
The insulating material 40 or the s-trips of insulating material
140 possess, in the longitudinal direction of the web, a uni-
form cross-section which, in the transversal direction of the
web, is rising in a cuneiform manner. In order to form a sui-
table slope, a gradient of 1%,2% or 3% is provided, it also
being possible to provide required intermediate values.
The sealing layer lamination 50 may consist of a material re-
inforced by a fabric 53 or of a non-woven pressed into a plas-
tic sheet, in which case provision may be made for the sealing
layer lamination 50, for the sake of a better adhesion of -the
insulating material strips 140, to be provided on its surface
with a non-woven or a fabric of polyester or glass fibers or
organic fibers, such as jute or the like.
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By preference, the strips of insulating ma-terial 140 are bon-
ded on in the form of a strand in a laminating machine and
are subsequently formed into cut insulating material 40, it
being possible to provide in -this case for the insulating ma-
terial 40 to be fabricated in panels and that, when the strips
of insulating material are cut, the panels are not cut right
through so that a connection of the strips of insulating ma-
terlal still exists for bonding on in large areas.
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