Note: Descriptions are shown in the official language in which they were submitted.
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RELEASABLE ADHESIVE ;JOINT, A METHOO FOR ESTABLISHING
A RELEASABLE ADHESIVE JOINI AND_AN APPARATUS FOR
RELEASING SUCH AI~IESIVE_JOINTS
BACKGROUND OF THE INVENTION
The present invention refers, according to a first
aspect, to a releasable adhesive joint between two elements in
which the two elements are fixed to each other by means o~ an
adhesive bead. According to a second aspect, the present inven-
tion further relates to a method for establishing a releasable
adhesive joint between two elements by providing an adhesive
bead of particular design between the two elements to be fixed
to each other. In a third and final aspect; the present inven
tion further relates to an apparatus for releasiny such an ad-
hesive joint fixing two elements to each other.
In the following, in accordance with the common lin-
guistic usage, th~ expression "adhesive joint" is used for a
connection or fixture between two rlgid elements by means of
one or a plurality o~ beads of adhesive material provided bet-
:~:
ween the two elements to be fixed to each other. Such adhesivejoints are very well suited, for instance, for mounting vehicle
windows in the body of the vehicle; examples of such adhesive
joints are disclosed e.g. in the European Patent Publications
EP-Al-O 312 496 and EP-A1-0 351 369. However, the usa~e and
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application of such adhesive joints is not limited at all ~or
mounting windows in a vehicle body.
Bven if this kind of glazing is very favourable and
may be successfully used in mounting panes or windows in a ve
hicle body in a quick and efficient way, the problem exists
that the pane or window must be removed from the vehicle body
in the case of repair of a broken pane or in the case of dis-
assembling the vehicle for recycling purposes. Up to now, no
efficient and quicXly to perform solution has been known for
releasing the adhesive joints between two elements, e.g. bet-
ween a vehicle pane and the vehicle body.
OB;IECTS OF THE INVENTION
It is an object of the invention to provide a releas-
able adhesive joint between two elements, particularly between
a vehicle pane and a vehicle body, which can be re~eased quick-
ly and efficiently in the case of repair or disassembling the
vehicle.
; It is a further ob~ect of the invention to provide a
method of establishing a releasable adhesive joint between two
elements, particularly between a vehicle pane and a vehicle
body, hy means of which such a releasable adhesive joint can be
realized.
It is a still further object of the invention to pro-
vide an apparatus for releasing such a releasable adhesive
~ joint in a convenient and efficient way.
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SUMMARY OF ~HE_NVENTION
~:.
To meet these and other objects, the invention provid-
es, according to a first aspect of the :invention, a releasable
adhesi~e j~int between two elements which are fixed to each
other by means of an adhesive bead. Tha adhesive joint compris-
es a heatable separating member closely fitting the adhesive
bead or embedded in the adhesive bead. The heatable separating
member looses the adhesion to the closely fitting parts of the ;~
adhesive joint or is destroyed upon heating the heatable sepa-
rating member to a temperature at which the adhesive bead is
not yet damaged, thus releasing the parts of the adhesive bead
closely fitting the heatable separaking member.
According to a second aspect, the invention further
;; pxovides a releasable adhesive joint between two elements which
are fixed to each other by means of a plurality o~ adhesive
beads. Thereby, the adhesive joint comprises a heatable sepa-
rating member closely fitting one of the adhesive beads or is
embedded in one of the adhesive beads. The heatable separating
memb~r looses the adhesion to the closely ~itting parts of the
adhesive joint or is destroyed upon heating the heatable sepa-
rating member to a temperature at which the one of the adhesive
beads closely fitting or containing the heatable separating
member is not yet damaged, thus releasing the parts o~ the one
of the adheslve beads closely fitting the h~atable separatiny
member.
To sum up it can be said that the releasable adhesive
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joint of the invention generally comprises a heatable separat-
ing member which either is in close contact to the adhesive
bead as well as to one of the elements to be fixed to another
one, or in close con-tact to one of the adhesive beads as well
as to one of the elements to be fixed to another one in the
case where more than one adhesive beads are used for the adhe-
sive joint, or is embedded in tha adhesive bead used to fix one
element to another one, or is embedded in one of the adhesive
beads in the case where more than one adhesive beads are used
for the adhesive joint. In any case, upon heating the heatable
separating member to a predetermined temperature, it looses the
adhesion to the closely fitting parts o~ the adhesive joint,
i.e. to the adhesive bead located next to it, or it is even
destroyed, with the result that the parts of the adhesive bead
closely fitting the heatable separating member are released
and, consequently, the adhesive joint is weakened or even de-
stroyed to such an extent that the two elements can be separat-
ed from each other without difficulties.
According to a particular embodiment, the heatable
separating member can be located on the sur~ace of one of the
two members to be fixed together and reliably fixed thereto.
Thereby, ~he adhesive bead or one of the adhesive beads used to
fix the two elements to each other is applied onto the surface
of the heatable separ~ting member. According to another embodi-
ment, the heatable separating member can be located in the in-
terior o~ the adhesive bead, if only one adhesive bead is used,
or in the interior of one of the adhesive beads, if two or more
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adhesive beads are usedO
Advantageously, the heatable separating member has the
shape and configuration of a flat body member. For instance, it
can be provided in the form of a thin layer, particularly a
thin film or foil, made of an electrically conducting thermo-
plastic material. The thin layer and the thin film or ~oil,
respectively, is provided with electrical connector means for
the supply of electric current.
;
According to another embodiment, the heatable separat-
ing member can be constituted by a thin film or foil made of a
plastic material which can be heated by the application o~ high
frequency, micro wave or infrared radiation.
In an embodiment of the releasable adhesive joint ac-
cording to the in~ention in which two adhesive beads are pro-
vided, one of the adhesive beads itsel~ can be designed as the
heatable separating member. In this case, the said one of the
.
adhesive beads is made of such a material which looses the ad-
hesion to the adjacent and closely fitting second adhe5ive bsad
at a temperature at which said second adhesive bead is not yet
damaged. It is even possible to design said one of khe adhesive
beads as a separating member which is destroyed at a tempera-
ture at which the second adhesive bead is not damaged. In any
cas~, the second adhesive bead is r leased and the two element
fixed to each other can be separated easily.
An important point is that the separating element
looses its adhesion to the remaining parts of the adhesive
joint or is destroyed at such a temperature at which the heat
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transferred to the related adhesive beadl cannot damage it. If
the usual adhesive materials are used, a damage of the adhesive
bead would occur at a temperature of about 200 to 250 C. It is
understood that the damaging process is time dependent. Due to
the low thermal conductivity of the plastic materials used as
adhesive agents, the temperature of the separating member can
be considerably higher than the temperature at which the adhe-
sive material is damaged, but only during a short time period.
The invention further provides a method for establish-
ing a releasable adhesive joint between to elements to be fixed
ko each other.
According to a first variation of the method, there is
provided an adhesive bead and a heakahle separating member
closely fitting the adhesive bead or embedded in the adhesive
bead, the heatable separating member loosin~ the adhesion to
the closely fitting elements or parts of the adhesive joint or
being destroyed upon heating it to a temperature at which the
adhesive bead is not yet damaged, thus releasing the parts o~
the adhesive bead closely fitting the heatable separating mem-
ber. Then, the adhesive bead is applied to one of the elements
to be fi~ed to each other, and the other one of the elements is
pressed against the adhesive bead.
According to a second variation of the method, a plu-
rality of adhesive beads and a heatable separating member
closely fitting one of these adhesive beads or embedded in one
o~ these adhesive beads are provided, whereby the heatable se-
parating member looses the adhesion to the closely fitting ele-
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ments or parts of the adhesive joint or is destroy~d upon heat-
ing it to a temperature at which the one of the adhesive beads
closely fitting or containing the separating member i5 not yet
damaged, thus releasing parts of the one of the adhesive beads
closely fitting or con'taining the heatable separating member.
Then, the plurality of adhesive beads is applied to one of the
elements to be ~ix~d to each other, and finally the other of
the elements is pressed against the adhesive bead.
According to a third variation of the method, there is
provided a first adhesive bead and a heatable separating member
closely fitting the first adhesive bead or embedded in the
first adhesive bead, whereby the heatable separating member
looses the adhesion to the closely fitting elements or parts of
the adhesive joint or being destroyed upon heating it to a t~m-
perature at which the first adhesive beads is not yet damaged,
thus releasing the parts of the first adhesive bead closely
fitting the heatable separating member. Then the first adheslve
bead is applied to one of the elements to be fixed to each
other. Thereafter, the first adhesive bead e~uipped with or
closely contacting the heatable separating member is cured.
Finally, a second adhesive bead is applied onto the cured first
adhesive bead, and the other one of the two elements is pressed
to the second adhesive bead.
If the heatahle separating member is to be embedded
into the adhesive bead or into one of the adhesi~e beads prior
to applying the adhesive bead to on of the two elements to be
~ixed to each other, th~ embedding is advantageously performed
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by coextrusion o~ the heatable separatiIIg member together with
the corresponding adhesive bead.
However, it is also possible to apply the heatable
separating member to the surface of one of the two Plements to
be fixed to each other prior to applying the adhesive bead or
one of the adhesive beads, for instance by spraying, painting
or printing a layer of suitable material, or by rolllng-on an
electrically conducting plastic material ~ilm or foil, or by
rolling-on a plastic material film or foil which can be heated
by means of high fre~uency, micro wave or infrared radiation,
; or by applying a plastisol to the surface of one of the two
elements to be fixed to each other which plastisol can be heat-
ed under the influence of high frequency, micro wave or infra-
red radiation.
Particularly suitable materials to be used as the
thermoplastic layer of the heatable separating member are the
following substances:
polyolefines, particularly polyethylene, atactic poly-
propylene, polybutene and the copolymers thereof;
~ ethylene-vinylacetate copolymers;
:~ ethylene-acrylic acid copolymers;
ethylene-methacrylic acid copolymers and corresponding
metal salts;
: grafted and/or segmented ethylene vinylacetate copoly-
mers;
ethylene-propylene-diene copolymers;
thermoplastic polyurethanes;
; saturated polyesters and copolyesters;
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Polyamides and copolyamides;
polyacrylates and polymethacrylates; and
triblock and biblock copol~mers, particularly co-
polymers consisting of polyamide, polyester and/or polyether
blocks, and of polystyrene, polybutadiene and polyisobutylene
blocks.
If adhesive beads made oP a polyurethane based materi- ;~
al are used, there may arise the di~iculty that these beads
show a poor adhesion to separating members made o~ polyethylene
based materials. This difficulty can be avoided by using an
ethylene-acrylic acid copolymer having 9 to 20~ by weight of
acrylic acid as a separating member. 5uch products are distri-
buted by "The Dow Chemical Company9', Mi~land, MI 48674, USA,
under the trade name "Primacori'. Very well suitable products
are, for instance, "Primacor 1430", "Primacor 5980" and "Prima-
cor 5990".
~ Similar products on the basis of methacrylic acid and
its metal salts are distributed by "Du Pont" under the trade
name "Surlyn".
The electric conduckivity of the material of the sepa-
ra~ing member, i.e. the layer, film or foil or the plastisol,
.,:,
- can be created or improved by adding an electrically conductive
.
material in Eine dispersion to the base material during its
preparation. Examples of such materials are listed below:
- polymers ha~ing intrinsic conductivity;
,~,;
electrically conductive carbon blacks;
graphite;
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metallic powcler, metallic fibres, metallic needles,
particularly made of aluminum, copper, silver or tungsten;
fillers coated with metal, particularly coated with
aluminum, copper, silver or tungsten;
metal coated micro balls and metal coated textile
fibres; and
mixtures of these materials.
Polymers having intrinsic conductivity are insoluble
and not-meltable polymers the pi-electron system o~ which has
been altered to a poly radical cation salt by protonation.
Thereby, a high electrical conductivity oE up to 102 S/cm and
more, corresponding to a resistivity of less than 10
Ohm.cm. Suitable representatives of such materials particularly
are polyaniline (PAni~ and its blend with polyvinyl chloride
(PAni/ /PVC). Such products are distributed, for instance, by
Zipperling Kes~ler ~ Co., D~2070 Ahrensberg, Germany, under the
txade name "Versicon" and by Americhem Inc., Cuyahoga Falls,
44222~0375 OH, USA, under the trade name "Incoblend".
As metal coated textile fibres, particularly metal
coated polyacrylonitrile fibres ~PAN) are preferred. These
fibres have a resistivity of less than 10 3 Ohm.cm, corre-
sponding to a conductivity of more than 103 S/cm. Such a pro-
duct is distributed by Texmet, I-28100 Novara, Italy, under the
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tracle name "Texmet".
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I~ the heatable separating member is electrically con-
ductive~ the releasing of the adhesive joint, ecg. cluring re-
pair of a vehicle, is accomplished by supplying an electxic
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current to the separating member in order to heat it up. The
heating of the separating member by means of electric energy
can be performed by means of direct current or alternating cur-
rent. In order to render ine~fective possible breaks or gaps in
the flat heatable separating member originating from breaking
the vehicle pane, it is advantageous to use high frequency al-
ternating current for heating the separating membsr.
On the other hand, if the separating member is consti-
tuted by a plastic material film or foil heatable under the
influence of high fre~uency, micro wave or in~rared radiation,
a high frequency, micro wave or infrared radiation source is
provided to heat the separatîng member. Of course it is requir-
ed that the selected radiation really can reach the place where
the heating should occur, be lt due to the geometry of the ad-
hesive bondj be it due to the kind of materlal of at least one
of the elements to be fixed together, If one of the elements
consists of glass as is usually the case with panes or windows
for vehicles, this requirement is normally fulfilled as glass
is permeable for the ~inds of radiation mentioned above. In the
case of an adhesive joint between two metallic ~lements, such a
heating is possible only in the presence of a specific geometry
of the adhesive joint.
Advantageously, the heating of the heatable separating
member is performed to a temperature of at least 100 C, pre-
ferably to 150~ C.
In the case of repair, i.e. in the case when a damaged
vehicle pane has to be replaced by a new one, a separating sur-
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face in the adhesive joint as smooth as possible is desired
which can serve as a basis ~or a new adhesive joint without the
need ~or a follow-up treatment. Due to these reasons, the first
embodiment of tha adhesive joint according to the invention
with a flat shaped heatable separating member is preferred.
In the case of disposal, however, i.e. when a vehicle
has to be disassembled for recycling the different materials
~steel, aluminum, glass, plastic etc.)( the quality of the se-
parating surface in the adhesive joint is of no further impor-
tance; thus, also other heatable separating members than flat
shaped ones can be used. The same goes ~or particular geometric
situations, for instance i~ very thin adhesive beads are pre-
sent.
According to a further embodiment of the invention,
the releasable adhesive joint comprises a first and a second
adhesive bead whereby the first adhesive bead itself constitut-
es the heatable separating member. It will loose the adhesion
to the closely fitting parts of the adhesive joint or will be
destroyed upon heating th~ first adhesive bead to a temperatuxe
at which the second adhesive bead is not yet damaged, thus re-
leasing the second adhesive bead closely fitting the fixst ad-
hesive bead.
As a basis material for such adhesive beads serving
simultaneously as heatable separating member, the products dis-
tributed by "The Dow Chemical Company", Midland, MI 48674, USA,
under the trade name "Primacor Adhesive Polymer" is very suit-
able. Particularly good experiences have been made with the
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products distributed under the trade name "Primacor 5980" and
"Primacor 5990".
BRIEF DESCRIPTION OF ~HE DRAWINGS
In the following, a number o~ preferred embodiments of
the releasable adhesive joint will be further described, with
refarence to the accompanying drawings, in which:
Fig. 1 shows a partial cross-sectional view of a ve-
hicle pane mounted into a frame of a vehicle body ~y a releas-
able adhesive joint, according to a first embodiment;
FigO 2 shows a partial cross-sectional view of a ve-
hicle pa~e mounted into a frame of a vehicle body by a releas- ..
able adhesive joint, according to a second embodiment;
~ ig. 3 shows a partial cross-sectional view of a ve-
hicle pane mounted into a ~rame of a vehicle body by a releas-
able adhesive joint, according to a third embodiment;
Fig. 4 shows a partial cross-sectional view of a ve-
hicle pane mounted into a frame of a vehicle body by a releas- :
a~le adhe~ive joint, according to a fourth embodiment;
Fig. 5 shows a paxtial cross-sectional view o~ a ve-
hicle pane mounted into a frame o~ a vehicle body by a releas-
able adhesive joint, according to a sixth embodiment;
Fig. 6 shows a partial cross-sectional view of a ve
hicl~ pane mounted into a frame of a vehi d e body by a releas-
ble adhesive joint, according to a sixth embodiment;
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Fig. 7 shows a partial cross-sectional view of a ve~
hicle pane mounted into a frame of a vehicle body by a releas-
able adhesive joint, according to a seventh embodiment; and
Fig. 8 shows a partial cross-sectional view of a ve-
hicle pane mounted into ~ frame of a vehicle body by a releas-
able adhesive joint, according to a eighth embodiment.
DETAI~ED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following description, reference is made to the
drawings in which, as a typical example, a glass pane is shown
which is fixed to the frame of a vehicle body. However, it is
understood that the releasable adhesive joint in accordance
~ith the invention can be used to fix two arbitrary elements to
each other and the examples described hereinbelow are just il-
lustrative.
Fig. 1 shows a vehicle body frame 114 in a partial
.. . .
cross-sectional view. A glass pane 110 is releasably mounted to
the vehicle ~rame 114 For this purpose, there is provided a
single ~dhesive bead 112 having trapezoidal cross section. Bet-
-~ ween the adhesive bead 112 and the surface 116 o~ the glass
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~: pane 110, there is provided a heatable separating member 118
- constituted, for example, by a flat shaped thin plastic ma-teri-
al Poil made of a suitable material as hereinbefore described.
~: If the heatable separating member 118 consists of an electri-
,
cally conducting material, it is provided with electrical con-
nectors (nok shown) in order to be connected to a source of
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electric power to heat ~t up. If, however, the heatable sepa-
rating member 118 consists of a material hea~able under the
influence of high frequency, micro wave or infrared radiation,
no electric connectors are required.
The heatable separating member 118 closely fits both a
edge portion of the surface 116 of the glass pane 110 and the
surface of the adhesive bead 112 facing the glass pane 110.
Thus, upon heating the separating member 118, the adhesion bet-
ween the separating member 118 and the adhesive bead 112 is
lost and the glass pane 110 can be removed easily from the ve-
hicle body frame 114. After removal of the ylass pane llO, the
free surface of the adhesive bead 112 shows a smooth finish
suitable for receiving a new glass pane 110 without the need
~or a follow-up treatment of this surface.
According to Fig. 2, there is agaiI~ provided a vehicle
body frame 214 into which a glass pane 210 is fixed. For this
purpose, there is provided a single adhesive bead 212 having
..
~ trapezoidal cross section. The adhesive bead 212 closely fits
: ^
~, the surface 216 of the glass pane 210 as well as an edge por-
tion of the vehicle body frame 214. Embedded in the interior of
,
the single adhesive bead 212, there is provided a heatable se-
~- parating member 218 constituted/ for example, by a flat shaped
thin plastic material fvil madP of a suitablP material as here-
inbefore described. Preferablyr the adhesive bead 212 and the
heatable separating member 218 are applied to the sur~ace 216
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of the glass pane 210 b~ coextrusion.
If the heatable separating member 218 consists of an
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electrically conducting material, it is provided with electri-
cal connsctors (not shown) in order to be connected to a source
of electric power to heat it up. If, however, the heatable se-
parating member 218 consists of a material heatable under the
influence of high requency, micro wave or infrared radiation,
no electric connectors are required.
Upon heating the separating member 218, the adhesion
between the separating member 218 and the closely fitting upper
and lower portions of the adhesive bead 212 is lost and the
glass pane 210 can be removed easily from the vehicle body
frame 214 because only a narrow edge portion of the adhesive
bead 212 fixes the glass pane 210 to the frame 214. After re-
moval of the glass pane 210, the free surface o~ the lower por-
tion of the adhesive bead 212 shows a smooth fi~ish suitable
for receiving a new glass pane 210 without the need for a fol
low-up treatment o this surface.
., ,1 .
According to Fig. 3, there is again provided a vehicle
body frame 314 into which a glass pane 310 is fixed. For this
purpose, there are provided two adhesive beads 312 and 313 to-
gether having trapezoidal cross section. The adhesive bead 312
~-losely fits the surface 316 of the glass pane 310 as well as
the upper surface of a heatable separating member 318 inserted
between the two adhesive beads 312 and 313. The adhesive bead
313 closely ~its the lower surface of the heatable separating
member 318 as well as an edge portion of the vehicle body frame
314. The heatable separating member 318 is constituted, for
example, by a flat shaped thin plastic material foil made of a
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suitable material as hereinbe~ore described. If the heatable
separating member 3~8 consists of an electrically conducting
material, it i5 provided with electrical connectors ~not shown)
in order to be connected to a source of electric power to heat
it up. If, however, the heatable separating member 318 consists
of a material heatable under the influence of high frequency,
micro wave or infrared radiation, no electric co~nectors are
required.
Upon heating ths separating member 318, the adhesion
between the separating member 318 and the closely fitting upper r
and lower adhesive beads 312 and 313 is lost and the glass pane
310 can be removed easily from the vehicle body frame 314. Af-
ter removal of the glass pane 310, the free sur~ace o~ the
lower adhesive bead 313 shows a smooth finish suitable for re
:
ceiving a new glass pane 310 without the need for a follow-up
treatment of this surface.
According to Fig. 4, there is again provided a vehicle
body frame 414 into which a glass pane 410 is fixed. For this
purpose, there are provided two adhesive beads 412 and 413.
Inserted betweèn the surface 416 of the glass pane 410 and the
upper adhesive bead 412, there is provided a heatable separat-
ng member 418. The adhesive bead ~12 closely fits the surfac
of the heatable separating member 418. The adhesive bead 413
closely fits the surface of the edge portion of the vehicls
body frame 414. The heatable separating member 418 is consti-
tuted, for example, by a flat shap~d thin plastic material foil
made of a suitable material as hereinbefore described. If the
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heatable separating member 418 consists of an electrically con-
ducting material, it is provided with electrical connectors
(not shown) in order to be connected to a source of electric
power to heat it up. If, however, the heatable separating mem-
ber 418 consists of a material heatable under the influence of
high ~requency, micro wave or infrared radiation, no electric
connectors are re~uired.
In this embodiment, first the heatable separating mem-
ber 418 is applied to the surface 416 o~ the glass pane 410.
Thereafter, the ~irst adhesive bead 412 is applied to the free
sur~ace of the heatable separating member 418 and then cured.
After curing, the second adhesive bead 413 is applied to the
first adhesive bead 412 and the glass pane thus prepared is
inserted lnto the frame 414 and pressed thereagainst until also
the second adhesive bead 413 lS cured.
Upon heating the separating member 418, the adhesion
between the separating member 418 and the closely fitting upper
adhesive bead 412 is lost and the glass pane 410 can be removed
easily from the vehicle body ~rame 414. A~ter removal of the
glass pane 410, the free surface of the upper adhesive bead 412
shows a smooth finish suitable for receiving a new glass pane
410 without the need for a follow-up treatment of this surface.
Fig. 5 shows an embodiment similar to the one shown in
Fig. 1 with a vehicle body frame 514 in a partial cross-sec-
tional view. A glass pane 510 is releasably mounted to the ve-
hicle frame 514. For this purpose, there is provided a singl~
adhesive bead 512 having trapezoidal cross section. Between the
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adhesive bead 512 and the surface of the vehicle body frame
514, there is provided a heatable separating member 518 consti-
tuted, for example, by a flat shaped thin plastic material foil
made of a suitable material as hereinbefore described. If the
heatable separating member 518 consi~ts of an electrically con-
ducting material, it is provided with electrical connector~
(not shown) in order to be connected to a source of electric
power to heat it up. If r however, the heatable separating mem-
ber 518 consists of a material heatable under the influence of
high frequency, micro wave or infrared radiation, no electric
connectors are required.
Fig. 6 shows an embodiment similar to the one shown in
Fig. 4 with a vehicle body frame 614 in a partial cross-sec-
tional view. A glass pane 610 is releasably mounted to the ve-
~.~
- hicl~ frame 614. For this purpose, there are provided two ad-
hesive beads 612 and 613. No separate heatable separating mem-
, .. .
ber is re~uired, because in this embodiment, one of the two
adhesive beads 612 and 613 is made of a suitable material as
hereinbe~ore described, preferably the adhesive bead 612 which
:;
closely fits the surface of the vehicle body frame 614. If the
heatable adhesive bead 6I2 consists of an electrically conduct-
ing material, it is provided with electrical connectors (not
shown) in order to be connected to a source of electric power
to heat it up. If, however, the heatable adhesive bead 612 con-
sists of a material heatable under the in-fluence of high fr~-
quency, micro wave or i~frared radiation, no electric connect
ors are reguired.
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Upon heating the adhesive bead 612, it looses its ad-
hesion to the vehicle body frame 614 and/or to the second ad-
hesive bead 613 such that the glass pane 610 can be easily re-
moved, together with the second adhesive bead 613 which closely
fits the surface 416 of thé glass pane 610.
Fig. 7 also shows an embodiment similar to ~he one
shown in Fig. 4 with a vehicle body frame 714 in a partial
cross-sectional view. A glass pane 710 is releasably mounted to
the vehicle frame 714~ For this purpose, there are provided two
adhesive beads 712 and 713. A heatable separating member 718 is
inserted between the upper portion 712B and the lower portion
712A of the ~irst adhesive bead 712 which closely fits the sur-
face 716 o~ the glass pane 710. The separating member 718 is
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made of a suitable material as hereinbefore described. If the
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heatable separating member 718 consists of an electrically con-
. ,
ducting material, it is provided with electrical connectors
(not shown) in order to be connected to a source of electric
powar to heat it up. If, however, the heatable separating mem-
ber 7:L8 consists of a material heatable under the influence of
high frequency, micro wave or infrared radiation, no electric
connectors are required.
The lower adhesive bead 713 closely fits both the
lower portion 712A of the first adhes~ve bead 712 as well as
the surface o~ the vehicle body frame 7~4.
In this embodiment, first the adhesive bead 712 con-
sisting of the upper and lower portions 712B and 712A together
with the heatable separating member 718 is applied to the sur-
.
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face 716 of the glass pane 710, preferahly by coextrusion and
then cured. After curing, the second adhesive bead 713 is
applied to the ~irst adhesive bead 712 and the glass pane 710
thus prepared is insertPd into the frame 714 and pressed there-
against until also the second adhesive bead 713 is cured.
Upon heatlng ~he separating member 718, it looses its
adhesion to the upper portion 712B and/or to the low~r portion
712A of the adhesive bead 712 such that the glass pane 710 can
be easily removed, together with the first portion 712B of the
adhesive bead 713 which closely fits the surface 716 of the
glass pane 710. After removal of the glass pane 710, the free
surface of the lower portion 712A of the adhesive bead 712
shows a smooth finish suitable for receiving a new glass pane
710 without the need for a follow-up treatment of this surface.
Finally, Fig. 8 also shows an embodiment similar to
the one shown in Fig. 4 with a vehicle body frame 814 in a
partial cross-sectional view. A glass pane 810 is releasably
mounted to the vehicle frame 814. For this purpose, there are
provided two adhesive beads 812 and 813. A heatable separating
member 818 is embedded in the adhesive bead 813 which closely
fits the surface of the vehicle body frame 814. The adhesive
bead 812 closely fits the surface 816 of the glass pane ~10.
The separating member 818 is made of a suitable mate-
rial as hereinbefore described. If the heatable separating mem-
,
ber 818 consists of an electrically conducting material, it isprovided with electrical connectors (not shown) in order to be
connected to a source of electric power to heat it up. If, how-
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ever, the heatable separating member 818 consists of a material
heatable under the influence of high frequency, micro wave or
infrared radiation, no electric connectors are reguired.
~ .
The lower adhesive bead 813 closely fits both the
:.
upper adhesive bead 812 as well as the surface of the vehicle
; body frame 814.
.`~ In this embodiment, first the adhesive bead 812 to-
gether with the heatable separating member 818 is applied to
; the surface 816 of the glass pane 810, pre~erably by coextru-
sion, and then cured. After curing, the second adhesive bead
813 is applied to the ~irst adhesive bead 812 and the glass
pane 810 thus prepared is inserted into the frame 814 and
pressed thereagainst until also the second adhesive bead 813 is
.~ cured.
if Upon heating the separating member 818, it looses its
.~ adhesion to the lower adhesive bead 813 such that the glass
~ .
pane 810 can be easily removed, together with the upper ad-
hesive bPad 813 which closely fits the surface 816 of the glass
pane 810 because the two adhesive beads 812 and 813 are con-
nected to each other only by very small edge portions which
easily can be destroyed.
: . EXAMPLES OF APPLICATION
The ~ollowing examples of application describe heating
tests which have been performed with electrically conductive
polymsr foils.
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EXAMPLE 1
r
In this example, use was made of a foil distributed
~: under the trade name "PE 105 LF", i.e. a polyethylene rendered
electrically conductive by adding carbon black thereto, by
- Zipperling Kessler & CoO, D-2070 Ahrensberg, Germany. The xe-
:
sistivity of this material amounts to 0.5 ohm.cm, corresponding
to a conductivity o~ 2 S/cm. It has been tested in the form of
an elongated tape.
:'',,
Test Conditions
Tape length:400 cm 200 cm 200 cm
Tape width: 10 mm 10 mm 10 mm
Tape thickness:1 mm 1 mm 1 mm
Frequency: 50 cps 50 cps 50 cps
: Voltage (AC):260 V 260 V 260 V
. Initial Temperature: 30 C 30 C 30 C
` .
Initial Measurement Values
Resistance:3200 ohm 1900 ohm 940 ohm
Power Consu~ption: 21.13 W 35.58 W 71.91 W
:'
. Measured Values after 5 min
. : Temperature:40 C 55 C 100 C
Heating Time5 min 5 min 3.5 minl)
Resistance:3300 ohm 2100 ohm 1700 ohm
Power Consumption: 20.48 W 32.1~ W 39.76 W
1~ So~t after 2 min, sticky after 3 min,
test stopped after 3.5 min.
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EXAMPLE 2
In this example, use was made o~ a foil distributed
under the trade name "Primacor 5980" containing 20~ by weight
carbon black and 5% by weight polyacrylonitrile fibres coated
with nickel, a test product of "Texmet", I-28100 Novara, Italy.
The resistivity of this material amounts to 0.1 ohm.cm, cor-
responding to a conductivity of 10 S/cm. It has besn tested in
the form o~ an elongated tape.
',
Test. Conditions
Tape length:400 cm 200 cm 200 cm
Tape width:10 mm 10 mm 10 mm
Tape thickness:2 mm 2 mm 2 mm
Frequency:50 cps 50 cæs 50 cps
Voltage (AC):260 V 260 V 260 V
Initial Temperature: 30 C 30 C 30 C
~ .
Initial Measurement Values
Resistance: 350 ohm 200 ohm120 ohm
Power Consumption: 195 W 340 W 560 W
Measured Values after 5 min
TemE)erature:~100 C ~100 C ~100 C
Heating Time2 min )1 min ) 0.5 min )
Resistance:3300 ohm2100 ohm 1700 ohm
Power Consumption: 20.48 W 32.19 W 39.76 W
-;
1) Heating test terminated, since the poly-
mer had molken.
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