Note: Descriptions are shown in the official language in which they were submitted.
Background of the invention
As a rule, sealing-compounds having elastic proper-
ties r notably for roofs, are manufactured by using a
reinforcement, base or carrier structure coated with
a binder consisting of bitumen and a polymer.
Since the addition of polymer to a bitumen impro-
ves the elastic properties of the sealing-compound in
proportion to the quantity of polymer added thereto, only
a few parts of polymer for hundred parts of bitumen are
sufficient for imparting the desired elasticity to the
end product. Unfortunately, during the natural aging of
the sealing-compound on the roof, this product is attacked
by weather conditions so that the polymer contained in
the binder is destroyed superficially, and cracks develop
in the surface of the polymer. The cracks thus formed
obviously fa~ilitate the detrimental penetration of rain
and humidity, thus leading eventually to a complete
destruction of the binder.
Description of the prior art
The only palliative hitherto found ~or combating
this inconvenience is to introduce an excess of polymer
for the purpose of extending the useful life of the sea-
ling-compound. In this case, the quantity of polymer to be
used becomes two to three times the amount necessary for
obtaining the desired elastic properties. Now the CQSt of
polymer, considerably high in comparison with that of bitu-
men, increases the cost of the binder and consequently the
- final cost of the product, which is doubled and sometimes
even tripled.
Summary of the invention
It is the primary object of the present invention
to solve this problem while providlng the additional
advantage of leading to a still greater improvement in
the sealing action of the product through an adequate
combination of its component elements.
The present invention provides a sealing compound
having elastic properties, adapted for use as a surface
protection material and consisting of a reinforcement covered
with a bitumen and polymer binder, wherein said binder
consists of two parts, namely the surface binder having a
sufficient polymer contents to withstand weather conditions
and the main binder constituting the internal body of the
sealing-compound and having a polymer contents sufficient
to impart elastic properties to the sealing-compound.
As a result, the surface layer undergoing a slow
weathering due to its high polymer contents will not crack,
thus preventing the weather conditions to which it is
exposed from exerting a deep action, that is, penetrating
; into the main binder layer containing only the amount of
polymer necessary and sufficient for imparting the desired
elastic property to the sealing-compound.
Description of the preferred embodiments.
The polymer percentage of the layer constituting
the outer surface of the sealing compound and the polymer
percentage of the inner layer of the sealing compound are
selected notably from the ranges of 10 to 20 percent by
weight and 0,5 to 10% by weight; respectively, of the bitumen.
More particularly, 15% by weight of polymer may be used
in the outer layer~ in proportion to the bitum
-- 3 --
, . . .
,l ~i
~ 2~ 3
and 5 % by weight of polymer may be used in the inner
layer, in proportion of the bitumen. Among the polymers
suitable for use in this sealing-compound, styrene-
butadiene-styrene, and ethylene-propylene-diene-monomer
(EPDM) may be cited by way of example. The polymer incorpo-
rated in the surface layer may differ from the polymer
used in the body layer.
According to a preferred form of embodiment of
the sealing-compound of this invention, a protective
action having the same efficiency is obtained with this
product but at a lower cost in comparison with known
sealing-compounds having a maximal polymer content,
~ut this action may still be enhanced if a particular
geometry is given to the material. In fact, if the rein-
forcement is disposed at the junction plane between the
two layers, the crack resistance of the surface layer is
: further improved due to the strenghtening of this layer
due to the close proximity of the reinforcement and on
the other hand if cxacks develop, the reinforcement
will prevent them from propa~ating inwards of the sealing-
compound, thus decreasing the detrimental action of
weather agents~
In all cases, the armature may consist for exam-
ple of fibres of glass, polyester, polyamid, polyolefin,
polyvinylic substance or of a combination of such fibres.
The sealing-compound according to this inven-
tion is manufactured by using a method known per se, for
example by using coating cylinders or rollers, and
consists in depositing the body or main layer onto the
reinforcement, then the surface layer, or preferably the
body layer onto one face and then the surface layer onto
the other face of the reinforcement. The sealing-compound
is then subjected to the external finishing operations
kno~n per se, whether on the surface or subface, such as
slate grain or the appearance of colored rocks, sand,
mica powder, the use of metal sheets and films of any
character imparting special properties to the material.
The following examples illustrate the present
invention without limiting the scope thereof :
Example_l
A sealing-compound weighing 6 kg per sq. m.,
consisting of the following successive layers :
- One layer of colored gra~ular substance,
; constituting the finishing surface layer, about 1 kg/sq.m.
- One layer of bitumen/styrene-butadiene-
styrene binder containing lS % of polymer
with respect to the bitumen ... ~......................... ..." 1 kg/sq.m.
- A fibre glass armature ..................... ............. ..." 0-100 kg/sq.m.
- One layer of bitumen/styrene-butadiene
-styrene binder containing 5 ~ of
polymer in relation to the bitumen ......... ...." 3.800 kg/sq.m.
- A sand layer as a subface finishing layer " 0.100 kg/sq.m.
Exam~le 2
A sealing compound weighing 6 kg/sq.m., consis-
ting of the following successive layers :
- One layer of sand, as a surface
finishing layer ............................ ...." 0.100 kg/sq.m.
- One layer of bitumen/EPDM bitumen
containing 15 % of polymer in relation
to the bitumen ............................. ...." 1.500 kg/sq.m.
- One polyester fibre layer ... ,........................... ...." 0.100 kg/sq.m.
- One fibre glass layer .................. ................. ~ " 0.050 kg/sq.m.
- One layer of binder consisting of
bitumen and styrene-butadiene-styrene
polymer containing 5 % of polymer in
relation to the bitumen ~ O " 3.150 kg/sq.m.
- One layer of sand, as a subface
finishing layer .................. ~...................... ...." 0.100 kg/sq.m.
