Note: Descriptions are shown in the official language in which they were submitted.
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Glasbau Hahn GmbH & Co.KG, D-6000 Frankfurt 1 11464
Method of Producing a Layer of Plastics Material between two Glass
Panes and Apparatus for Performing the Method
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The present invention relates to a method and to an apparatus for
performing the metho~ of producing a layer or lamina of plastics
material between the two glass panes, wherein the plastics material
in liquid form is fed between the two glass panes being maintained
parallel and sealed at the outer edges thereof and a pressure is
exerted on the surfaces of the glass panes.
Such methods and apparat~s are already known. DE-AS 22 26 342, for
example, specifies a method of producing a laminated glass comprising
two glass panes bonded together by intermediate layer of self-curing,
transparent plastics material capable of being cast, said two glass
panes with a spacer separating and sealing the glass panes only at
the edges thereof, being leant in vertical position against a tilt-
able plate and the space between them being filled at least in part
with the liquid plastics material, the plate together with the two
glass panes is then tilted slowly towards the horizontal position
whereby a bulge or bowing in the glass pane averted from said plate
resulting from the pressure of the liquid plastics material in the
vertical position is reformed whereby the plastics material fills the
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whole space between the glass panes until an opening provided in the
spacer for the ventilation is closed. m e recession or reformation of
the bulge of the glass pane may also ~e effected additionally by
means of a suction cup connected by a hose to a subpressure source.
Furthermore, from DE-OS 27 28 762 a method is known of producing a
laminated glass pane, wherein the space between two horizontal panes
maintained parallel to each other by a spacer is filled with a
plastics material. Measures to avoid the tendency of the glass panes
to bulge outwards and inwards, respectively, which is caused by the
pressure of the plastics material filled in and by the weight of the
upper glass pane, are not considered in said publication.
Another method of producing laminated glass panes is specified in DE-
OS 26 06 569. According to said method, the plastics material is
filled into the interspace between the two glass panes in the in-
clined position and the curing proper takes place in the horizontal
position.
Further, from DE-PS 27 37 740 a method is known of producing a la-
minated glass consisting of two glass panes and one intermediate
layer wherein an already finished layer of plastics material is glued
as intermediate layer between the glass panes, and the glass panes
are pressed against the layer of plastics material by means of ro-
tatable rollers in order to avoid gas bubbles in the adhesive lamina.
This method of bonding glass plates and intermediate layer is, how-
ever, eXp nsive anD rs3Uires, mOreDVer, a pre-fabricate~ layer of
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plastics material.
CH-PS 574 371 relates to a sound-absorbing glazing in the form of a
laminated b~dy of two glass panes surrounding a layer of plastics
material. In a ~ethod of producing such a laminated body the glass
panes are placed in a water reservoir in the vertical position for
filling in the plastics material. In order to prevent the tendency of
the glass panes to bulge, the process is carried out with different
water levels depending on the pressure ratios and thickness of the
glass panes. This method does not limit the hydrostatic pressure but
compensates by hydrostatic counterpressure the continuously increas-
ing hydrostatic pressure which is extraordinarily high in case of
large glass panes. I'he elaborate and complicated character of this
method due to the large pressure-stable water reservoir is obvious
and does, moreover, not guarantee that the opposing glass panes are
plane-parallel, which is rendered still more difficult because, as it
is known, self-supporting glass panes are not entirely vertical.
Furthermore, from GB-OS 20 15 427 an arrangement is known in which
glass or plastics panes held in parallel by means of spacers are
placed in a vertical position when liquid material is filled in, the
spacers being provided in the interspace between the panes. The
liquid plastics material is filled into the interspace between the
panes at such a filling rate that the height of the not cured plas-
tics material does, as much as possible, not have the tendency to
effect a bulging. When the curing level rises, the spacers can be
withdrawn concurrently from the interspace between the panes. In
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order to avoid bends or bulges of the glass panes which have a long
vertical extension, a pair of opposite rollers is mounted for move-
ment over the front and rear surfaces of the glass panes. The bends
or bulges in the glass panes are obviously compensated statically
before the filling process begins.
I~ case of photo-curing plastics materials a W radiation source is
moved concurrently with the filling height from below to above over
the pane assembly. m e intention is to avoid thereby a curing of the
flowing in plastics material already above the filling level by UV
radiation.
It may be a disadvantage of this arrangement that only very slow
filling xates are possible with a maximum allowable height of the
column of the not cured plastics material of a few centimeters.
However, also the slow filling of columns of plastics material of a
few centimeters leads to a bulged or even wedge-shaped glass pane.
Moreover, only panes of smaller dimensions and greater thickness can
be produced. In paxticular, when the panes axe thin and when they
have a large vertical and latexal extension, the bulging of the panes
can by no means be avoided anymore solely by regulating the filling
rate.
It should also be considered that due to such slow filling rates a
homogenous intermediate layer free from reams cannot be achieved.
Moreover, the production process is very time-consuming. Furthermore,
the temporary provision of spacers between the panes and a proposed
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sealing of the spaced pane edges by means of adhesive tapes is
problematic with regard to the occurring shrinking process.
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It is the object of the invention to provide a method which can be
performed with simple means and a simple device f~r performing said
method which allows the production of flawless panes of plastics
material and/or laminated glass panes.
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In the method according to the invention filling process and curing
process are combined whereby a large number of technical problems are
overcome as they occur e.g. when the glass panes are brought in the
vertical position to render possible a good inflow of the plastics
material and to avoid inclusions of air bubbles. With the filling and
curing process according to the invention a high static pressure
which would destroy the necessarily soft sealing of the edges and
would cause a tendency of outward bulging of the glass panes is not
built-up even when the panes are set up vertically. The production of
glass panes of a uniform thickness and very large dimensions is
guaranteed. It is no problem to separate the finished sheet of plas-
tics material from the glass panes when a plastics material is used
which does not react with glass or when the inner surfaces of the
glass panes are provided with separating agents kefore the filling
process is started. In particular the method according to the inven-
tion gives the possibility of the combined production of very long
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laminas of plastics material. In particular, it is possible to pro-
duce laminated glass pa~es by the method according to the invention
in a simple way and of high quality. Laminas of plastics material may
be obtained up to any arbitrary filling level which are flawless and
free of air bubbles.
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Due to the quick curlng of the plastics material it is possible that
the devices to achieve a pressure (pressure devices) keep the glass
' panes separated at an exact distance during the filling process, that
; 10 a quick polymerisation of the plastics material is initiated, and
that the plastics material now solidifying has no flow properties
anymore which would cause a bulging-out of the glass panes. For this
purpose the pair of glass panes can be positioned vertically or in-
clined on a solid support and the uniform distance (between the glass
panes) during the filling process can be controlled from one side
e.g. by means of a course of rollers or drums. ~hen a glass pane is
in a preferred vertical position, oppositely arranged devices to
achieve pressure can also be carried along in conformity with the
filling process whereby it is e.g. also possible to fill the inter-
space of bent glass panes. m e method according to the invention also
allows a sandwich arrangement of more than two glass panes at adjust-
able distances.
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The apparatus according to the invention is a simple construction and
requires only substantially 'arbitrary devices to achieve pressure and
means for moving said devices and/or glass panes to effect the rela-
tive movement between glass panes and said devices.
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It may be advantageous to hold the glass panes in an inclined posi-
tion during the production process whereby the static pressure is
reduced and the total height of the arrangement is reduced to low
dimenslons also in case of large panes.
A further development of the invention is that the plastics material
is rapidly curable by intense external radiation. When a plastics
material is used which is curable by, for instance, intense ultra-
violet radiation, the curing rate may be determined quite exactly. In
order to consider production errors due to aging processes of the
radiaton source, its intensity can be regulated.
A further development of the invention is that one or more radiation
sources are located before or behind one of the two devices to
achieve pressure and are movable together with them. Depending on the
sensitivity of the material to be radiated and its thickness the
curing rate can be determined by switching on a plurality of light
sources respectively arranged between said devices.
A further development of the invention is that the plastics material
is fed in in conformity with the rate of motion of the pressure de-
vices which are respectively guided in the area of the liquid surface
of the plastics material. This allows that only the rate of inflow of
the plastics material must be controlled when the rate of the pres-
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sure devices and light sources is constant.
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A further development of the invention is that the plastics materialis fill~d in and the devices to achieve pressure are moved such that
said devices are always in the area of the liquid surface of the
plastics material. A constant filling rate is assumed therefor and
the rate ~f the pressure devices and of the radiation path is adapted
to the liquid surface of the plastics material. For example, when the
liquid is supplied uniformly, the filling rate is halved when the
interspace between the glass panes has been doubled.
A further development of the invention is that the plastics material
is curable by heat and that the heat may ~e supplied via the devices
to achieve pressure. This heat supply must not be caused by intense
radiation, but a microwave apparatus incorporated for instance in a
drum and travelling to and fro, if necessary, is adapted to heat
quickly filled-in materials without heating the glass, and to ini-
tiate a curing process.
A further development of the invention is that the pressure devices
extend over the total width of the glass panes.
A further development of the invention is that the radiation source
is arranged between two adjacent pressure devices so that in the area
where the plastics material is still liquid the glass panes can be
maintained in position by one pressure device, is then hit by a, for
instance, intense W radiation, that then another pressure device
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follows, and thereafter, perhaps, another intense radiation, then
another pressure device etc. This depends on the filling rate, the
required radiation intensity, the radiation capacity of the lamps, as
well as on the time required by the fed-in plastics material to lose
its flow property.
A further development of the invention is that the devices to achieve
pressure and the radiation source are not movable but stationary and
that the unit of glass panes is passed therethrough in an inclined
and vertical position, respectively. The production may be, for
example, a continuous production by guiding one pair of glass panes
after the other one through the positioning station and, e.g. through
the radiation station.
The devices to achieve pressure must not fulfill specific require-
ments. Besides drums and rollers hoses filled with liquid may be used
which have a more gentle effect on the surface. In order to prevent
the glass surfaces from being scratched, it is also possible to pro-
vide a protective sheet or film between pressure devices and glass
panes.
The devices to achieve pressure may be provided alternatively also
with pneumatic, hydraulic or mechanic (with spring action) control
devices which effect an exact pressure compensation over the total
surface of the glass pane when the pressure devices are moved.
It is also possible to move air-cushion developing aggregates rela-
tive to the glass panes whereby their surfaces are in no way damaged
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~ due to the non-contact pressure effect.
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A further development of the invention is that it is also possible to
process besides one-component plastics materials multi-component
materials. When surplus of plastics material (fat edges) occurs in
the interspace between the glass panes when the plastics material is
filled in, it is possible to convey the liquld to be filled in by
means of a thin hose, for instance a sausage skin, into the inter-
space between the glass panes untll up to the upper liquid level and
to heave it (the hose) continuously up and outwards with the liquid
level. The ratio of processing time to curing time in the presently
repeatedly used cast resins which are mixed shortly before they are
filled in is approximately 1 : 10. Thus, it may be considered in
conjunction with a mixing apparatus that a processing period of 30
seconds is utilized to reach the interspace between the glass panes
up to the surface of the plastics material from the proportioning
means via the hose. Within a period of 5 minutes a curing has then
occured here which is strong enough to at least eliminate the flow-
ability of the material. ~hen the pressure devices have a height of
about 1 m it is possible to fill the interspace between the glass
panes in 15 minutes up to a height of 3 m. With the presently usual
manufacturer's standard stock size for float glass production of 6 m
x 3.21 m it would be possible to produce about 80 m2 per hour. With
the present production methods a very complicated machinery and, in
particular, very much space is required to produce a glass pane of 6
m x 3.21 m. A substantial advantage of the invention is that the
above production is possible on a base surface of e.g. only 10 to 15
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m~. ~he halls in glass-processing installations have
usually the required height o~, like in the present
case, about 4 m. - without a pit.
A ~urther development of the invention is that the
vertically positioned or inclined glass pane can be
filled with prepared air or a different gas before the
liquid plastics material is filled in, which gas is
then expelled by the flowing-in and ascending liquid.
According to one's desire, the lattice-like
polymerization of plastics material and glass can, in
this way, be improved and deteriorated, respectively.
A further development of the invention is that the
temperature of the glass pane and of the liquid
plastics material to be filled in is different. When,
for example, the plastics material to be filled in is
heated, a precipitate is formed immediately at the
upper edge of the liquid column on the surface of the
glass which counteracts the adhesion of plastics
material to the glass.
According to a broad aspect of the present invention
there is provided a method of forming a sheet of
plastic material in a space between first and second
panes, each having a width and a length and an outer
surface and inner surface, sealed along the length
thereof. The method comprises feeding liquid plastic
material into the space between the inner surfaces of
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the panes to form a rising level of plastic material
therein. Pressure is applied adjacent the rising level
of liquid plastic material by pressure application
means extending over about the width of the outer
surface of the first pane, so that the panes are
pressed uniformly against the pressure application
means by the static pressure of the liquid plastic
material. The plastic material is cured and the
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application of pressure is continued for about the length
of the firs-t pane as relative movement of the first and
second panes and the press~re application means is effected
at about the rate of curing of the plastic material.
Accordlng to a further broad aspect of the present invention
there is provided an apparatus for forming a sheet of plastic
material. The apparatus comprises a first pane having an
outer surface, an inner surface, a length, and a width. A
second pane is provided and has an inner surface. Spacing
means is positloned between the inner surfaces of the first
pane and the second pane to form a space therebetween.
Delivery means is provided for feeding liquid plastic material
to the space between the inner surfaces of the first and
second panes to form a rising level of liquid plastic material.
Pressure application means is operatively associated with the
first pane for exerting pressure on the outer surface thereof
adjacent the rising level of liquid plastic material. Drive
means is provided for effecting relative movement of the first
and second panes and the pressure application means to cause
pressure to be exerted adjacent the rising level of liquid
plastic material on the outer surface of the first pane for
about the length thereof.
The invention will be explained hereinafter by means of the drawings,
wherein
Fig. 1 illustrates an e~x~iment of the apparatus according to the
invention,
Fig. 2 illustrates another embodiment of the apparatus according to
the invention, and
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~ig. 3 illustrates an embcdiment of the apparatus according to the
invention wherein a plurality of drums and radlation sources
are provided.
Fig. 1 shows a vertically positioned pane unit comprising two glass
panes 1, 1 and a spacing piece or a spacer 2 which are held in posi-
tion ~y pressure devices in the form of drums or rollers 4 running
before and behind (said panes) when liquid plastics material 3 is fed
in the interspace 5 between said panes. Especially with a vertical
arrangement it is possible to produce pane units of more than two
panes 1 at the same time, by filling the interspaces between the
glass panes simultaneously with liquid plastics material 3 which
requires special attention for example when the distances between the
glass panes are different. When the liquid level is maintained always
somewhat above the drums, the panes are pressed uniformly against the
drums by the static pressure. Multiple glass panes may, however, also
be produced one after the other by putting-on another pane and in-
` creasing the distance of the holding means to each other.
20Fig. 2 illustrates a table supporting the pane unit and the roller
course or assembly is moved together with a curing device provided
with radiation sources over the glass surface concurrently with the
filling process. During the filling process said table may be posi-
tioned vertically or it may be inclined depending on the flowability
of the plastics material, on the thickness of the pane or, e.g. also
on the available headroom. When the tableis at an inclined position
the uppermost glass pane is sagging which can easily be compensated
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by maintaining the filling degree of the glass pane at a somewhat
higher level than the concurrent drum and radiation unit, the static
pressure pressing the upper glass pane against the roller assembly
running above thus guaranteeing an optimum uniform thickness. con-
trary to the conven-tional methods the quantity filled in must not be
determined precisely beforehand but the completely filled interspace
5 directs that the filling process can be stopped.
Fig. 3 illustrates a stationary drum and radiation unit through which
the glass panes are passed while being filled. The position of said
unit is adjusted to be vertical or inclined depending on the consis-
tence of the liquid plastics material.
~ontrary to the embodiments according to Figs. 1 and 2 the latter
embodiment does not require a device for moving the devices to
achieve pressure. Instead a moving device for moving the glass pane
unit must be provided. As both moving means may be implemented in any
way desired, it was renounced to illustrate them.
The embodiments were explained in connection with the use of drums as
devices to achieve pressure. Meanwhile, however, rotatably mounted
rollers turned out to be good in practice. However, also a number of
other pressure devices such as those referred to at the beginning are
imaginable without cutting down the advantageous effect of the appa-
ratus according to the inventlon.
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