Note: Descriptions are shown in the official language in which they were submitted.
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SMB
Fusible Bitumen Joint Sealant Tape
The present invention relates to a fusible bitumen joint sealant tape for use
in road construction, civil and structural engineering and canal construction,
a process for its preparation, and a method of laying the joint sealant tape
at a seam/connecting flank of an asphalt layer in road construction.
Fusible bitumen joint sealant tapes for road construction, civil and struc-
tural engineering and canal construction are manufactured and are me-
chanically preformed thermoplastic tape profiles with various cross-sections
which essentially consist of bitumen or bitumen modifications as binders.
They may contain, for example, additions of plastic, elastomers, plasticiz-
ers and mineral fillers.
DE-U 77 28 361 describes a laying device for self-adhesive or fusible
sealant tapes, but no further details as to the configuration of the joint
sealant tapes can be seen.
DE-U 93 13 030 relates to ~ a shaped unsupported bitumen-containing
sealant material, for example, made from a premix of about 15% finely
shredded buna rubber and about 85% blended bitumen, which is admixed
with further blended bitumen, oil, slate flour and modified cellulose powder.
In particular, the thus formed tape is inserted cold in the seam flank and
without a primer.
DE 196 03 896 A1 describes a cold processable joint sealant tape and a
method of laying a joint sealant tape. In particular, a joint sealant tape is
described for use in road construction, consisting of a polymer-improved
road construction bitumen provided with an adhesive layer on at least one
side thereof. With this joint sealant tape, there is to be achieved the object
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of providing a joint sealant tape and a method which enable cold laying,
i.e., without the aid of a flame.
However, the application of an adhesive layer, as described therein, to the
joint sealant tape has a drawback in that the shelf life of the joint sealant
- tape can be adversely affected, as a rule, by the relative instability of
the
adhesive, in contrast to that of bitumen. In addition, an adhesive layer,
especially one based on SBS/SIS block copolymers, adversely affects the
adhesion of the joint sealant tapes to the joint flanks, especially if the
joint
sealant tape or the seam/connecting flank is slightly heated up with a
propane gas flame, or if the temperature of the mix for the asphalt or top
layer to be newly applied, which is brought immediately adjacent to the laid
joint sealant tape, is rather high.
It has been the object of the present invention to provide a bitumen joint
sealant tape for use in road construction, civil and structural engineering
and canal construction which is improved over those of the prior art.
According to the invention, this problem is achieved, in a first embodiment,
by a fusible bitumen joint sealant tape which comprises a bitumen-
containing fusible coating applied to at least one major surface of the tape.
While predominantly in the prior art, prior to applying the joint sealant
tape, a bitumen-containing primer has generally been sprayed or brushed
onto the seam/connecting flank, in order to support the adhesion of the
joint sealant tape when it is applied and also to bind dust, if any, it is
possible, using the present invention, to dispense with priming as a rule
when the outside temperatures are appropriate and the edges/flanks are
clean. The application of a primer can be dispensed with at all tempera
tures. After application by pressing with a wooden or metallic spatula or
another suitable tool, the joint sealant tape according to the invention
remains at the edge/flank by itself. The starting point of the invention is
the
fact that in practice, especially when the weather is unfavorable, it is known
to fuse the joint sealant tape to the seam/connecting flank on one side
J
thereof already, using a gas burner, in order to avoid laying problems. In
the prior art, corresponding outside temperatures are known. The con-
netting flanks are usually beveled, cut or precased and can consist of
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prefabricated building materials. They must be made as smooth as possi-
ble, be solid and free of contaminations; for example, rust particles must be
removed from steel parts.
The working of the joint sealant tapes should only be performed when the
weather is dry and the construction element has a surface temperature of
+S °C. At temperatures down to +/- 0 °C, the work can be
continued when
additional measures, such as preheating the seam and/or the flank, have
been established.
The invention provides a joint sealant tape which is already equipped with a
mounting aid/laying aid by manufacture and can be pressed against the
seam/connecting flank at all times of year even without using aids such as
a primer or a gas flame, and remains there until the fresh mix has been
applied against.
Conveniently, the fusible coating consists of a coating on one side of the
joint sealant tape which is predominantly comprised of bitumen in order to
avoid incompatibilities, especially with asphalt or concrete. In a
particularly
preferred embodiment of the present invention, the fusible coating consists
of polymer-improved bitumen. Such materials are sufficiently known to the
skilled person from the prior art.
The thickness of the fusible coating is not critical. However, the layer
should
be applied as thin as possible. It is particularly preferred according to the
present invention to provide the joint sealant tape with a fusible coating
which comprises a thickness of from 0.1 to 2 mm, especially from 0.2 to 1
mm.
According to the invention, the material of the actual bitumen joint sealant
tape is different from that of the bitumen-containing fusible coating. In
particular, it is preferred that the bitumen-containing fusible coating, for
example, made of polymer-improved bitumen, has a higher elasticity,
especially an improved cold flex temperature, an increased cone penetra-
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tion and an increased recovery as compared to the actual bitumen joint
sealant tape.
According to the present invention, it is particularly preferred for the
fusible
coating to have a cold flex temperature according to DIN 52123 of -20
°C,
while the cold flex temperature of the joint sealant tape should be +/- 0
°C.
This enables the working and laying of the joint sealant tape at tempera-
tures of down to about 0 °C.
Similarly, it is particularly preferred that the cone penetration according to
BS 2499 of the fusible coating is from at least 60 to 140 tenths of mm, and
the cone penetration of the joint sealant tape is from 20 to 50 tenths of
mm, provided that the difference between the cone penetration values is
from at least 20 to 60 tenths of mm. This ensures that the fusible coating
more closely fits to existing roughnesses of the seam and/or connecting
flank.
Also for an improved compensation of roughnesses of the seam and
connecting flank, it is particularly preferred according to the invention that
the recovery of the fusible coating according to BS 2499 is from at least
60% to 90% and the recovery of the joint sealant tape is from 15% to
55%.
The different physical properties of the bitumen joint sealant tape and the
bitumen-containing fusible coating can also be achieved, for example, by
selecting different bitumens. Thus, according to the present invention, it is
particularly preferred for the bitumen joint sealant tape to be made from a
polymer-improved bitumen having a relatively high content of fillers and
optionally fibrous components. On the other hand, when the starting
bitumens for the bitumen joint sealant tape and the bitumen-containing
fusible coating are the same, ~t is preferred according to the present
invention that the mineral content is lower and, in particular, that the
polymer content is higher in the bitumen-containing fusible coating as
compared to the bitumen joint sealant tape. Particularly preferred according
to the present invention is a joint sealant tape in which the bitumen-
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containing fusible coating comprises of from 60 to 93% by weight of
bitumen.
The bitumen-containing fusible coating can be applied to the joint sealant
tape in any of different ways. Since the use of a release paper already
employed in the prior art which covers the bitumen-containing fusible
coating is intended anyway, it may be convenient to prepare the joint
sealant tape according to the invention by first applying a fusible coating to
a release paper and then applying the joint sealant tape to the backside of
the fusible coating.
As an alternative to this embodiment of the preparation process, it is also
possible to first apply the bitumen-containing fusible coating to the joint
sealant tape and then to apply the release paper.
As an overall bonding of the bitumen joint sealant tape to the seam/con-
necting flank using the present invention is not desired during the working,
but just attachment of the joint sealant tape to the desired place is to be
achieved, it is particularly preferred according to the present invention to
apply the fusible coating, not as a continuous area on the surface of the
joint sealant tape, but only at certain points, optionally in the form of a
raster-like fusible coating. In particular, this saves material for the
fusible
coating, and according to the invention, the same adhering effect is
achieved which would also be achieved with a continuous large-area fusible
coating. Advantageously, however, it is possible to remove the joint sealant
tape prior to applying the mix without damaging the joint sealant tape. In
addition, a large-area contact of the material of the joint sealant tape with
the mix is provided which is interrupted only at certain points, optionally in
a raster-like form, by low surface fractions of the fusible coating.
Another embodiment of the present invention relates to a method of laying
a joint sealant tape according to the invention, especially at a seam/con-
necting flank of a top layer in road construction. According to the invention,
the joint sealant tape is made to adhere by pressing against it. Of course, it
has to be ensured that the fusible coating contacts the seam/connecting
flank.
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In the case where the weather conditions do not allow direct adhering of
the joint sealant tape, it is preferred, also according to the invention, to
slightly heat up the seam/connecting flank and/or the joint sealant tape
with a gas flame.
In an alternative embodiment, it is also possible to first provide the seam/
connecting flank with a brushable or sprayable, at least flat-coatable,
primer before the joint sealant tape is fixed by pressing against it. As the
primers, there may be used per se known primers as commercially avail-
able, for example, under the designation of Colzumix~.
The seams and/or flanks must be clean and dry. Sticking residues of dirt, in
particular, have to be removed with a wire brush or compressed air. Moist
flanks can be dried using hot air.
For greater lengths to be applied, it may be preferable to use mechanical
equipment.
