Note: Descriptions are shown in the official language in which they were submitted.
7463~
The present invention relates to a process for the manu-
facture of a new flexible and water-impermeable covering sheet
which possesses a fibrous reinforcement and is intended to ensure
complete water-impermeability in civil engineering works and
building works. The sheet obtained according to the invention
differs from the products used hitherto for the same purpose by
the fact that it combines perfect water-impermeability with
remarkable mechanical strength properties, especially excellent
resistance to tension, flexing, tearing and bursting.
It is already known to combine a textile carrier with
a conventional aqueous bitumen emulsion. This emulsion however
does not ensure complete impermeability because of the breaking
of the emulsion and elimination of the water liberated by this
breaking of the emulsion. Equally, it is known that the combin-
ation of a textile carrier and a conventional bitumen applied
hot does not ensure complete water-impermeability except when
the proportion of bitumen is above a very high value. In fact,
when the bitumen is employed in such proportions, the role of
the carrier virtually disappears and one can no longer consider
a combination to be involved. At lower proportions of bitumen,
that is to say when one is effectively dealing with a combination,
on the other hand, neither perfect water-impermeability nor satis-
factory behaviour at high temperatures is observed; in effect,
at these temperatures the viscosity of the bitumen decreases,
which causes a flow of the bitumen on the w~b, above all in
applications in a position other than the horizontal, and in
parallel therewith causes the disappearance of the homogeneity
-2- ~
~ -
33L
of the combination. Furthermore, the use of certain special bitumens,
and especially oxidised or filled bitumens does not make it possible
to produce the combinations directly on the construction site and requires
factory manufacturc.
Furthermore, using the products currently available on the market
requires, at the stage of assembling various widths, the use of special
devices and, especially, the use of gluing binders or the supply of a
large amount of heat in order to ensure self-adhesion by pressure.
Finally, as men~ioned above, the products currently on the market do not
at one and the same time exhibit the required set of mechanical properties
and complete impermeability.
The present invention provides a process which makes it possible
to manufacture a new, homogeneous covering sheet which combines all the
abovementioned properties. ~le process of the invention comprises:
heating to a temperature of about 125 to 160C a binder consisting
of an emulsion of sulphur in bi~umen in a ratio between 15:85 and 30:70
by weight, the mean size of the sulphur droplets not exceeding 10 microns;
adding to the binder one or more additives suitable for the application
envisaged for the sheet;
and impregnating a fibrous material uniformly at a temperature oE 125 to
145C with this binder to give an impregnated sheet in which the fibrous
ma~erial to binder ratio is between 1:0.5 and 1:60 by weight preferably
1:10 by weight, the fibrous material weighing 10 to 1000 g/m and consisting
of (A) one or more non-woven fabrics of continuous or short fibres selected
from the group consisting of polyester, polyamide, polyvinyl chloride,
acrylic or inorganic materials or fibres made from copolymers of any of the
above
-- 3 --
'1 ..~ .
. ~ : .
~7463~
materials or fibres made from mixtures of any of the above
materials with each other or with polyolefines; or (B) a woven
fabric comprising continuous or short polyolefine fibres or
fibres made from any of the materials listed in A; or (C) a
composite made up of a woven fabric and a non-woven fabric, each
of which fabrics may be of continuous or short fibres made from .
any of the materials listed in B.
Examples of fibres used in the non-woven fabrics or
in the woven fabrics, or in the composites of one with the other,
are given below, with some indications of the melting points or
decomposition points: -
Polyesters (melting point between 245 and 290C),
especially based on terephthalic acid and ethylene glycol
(Dacron ~ , Diolen ~ , Terylene ~ , Trevira ~; melting point
256C.), those polyesters resulting from the partial replacement
of these components, for example by naphthalene-2,6-dicarboxylic
acid, 1,4-bis-(hydroxymethyl)-cyclohexane or 1,4-butanediol, and
those based on 4-hydroxybenzoic acid;
Polyamides based especial.ly on ~-captrolactam (Nylon 6,
Perlon ~ , Caprolan ~ ; melting point 215C.), on laurolactam
.
``~ '74633L
~Nylon 1~), or on 1,6-hexanediami.ne and a~ipic acid (Nylon
6,6; melting point 260C), sebacic acid, dodecanoic acid
and the like;
polyvinyl chlorides as such (Clevyl R ~ melting point/
¦ 5 decomposition point about 180-200C) and above all in the ~orm
of copolymers,,in par-ticular wlth acrylonitrile (modacrylic
fibres; Dynel ~ Vinyon N ~ softening point about 150C)
and with vinyl acetate ~Vinyon HH ~);
I polyacrylic fibres, that is to say fibres made fromZ 10 acrylonitrile (Orlon ~ Dralon ~ Acrilar. ~; melting point
330C)and rrom its copolymers with ~inyl acetate, allyl alco-
holsj acrylic and methacrylic .esters and vinyl chloride
~modacrylic fibres; see above);
~ inGrganiC fibres, especially glass fibres and asbestos
~ibres;
finally, in the case of woven fabrics and in the case
of mixtures of non-wo~ens of dif~erent chemical composition,
polyole~ines such as polypropylene (melting point 175C) and .
I polyethylene (melting point 135C~. .
`~ . 20 The. fibrous material which is preferably employed in
¦ the process according to the invention consists of (A') a
non-woven of inorganic fibres or of polyesters o~ of
I polyamides, or of mixtures of the preceding materials with one
3 "
another or with polyolefines, o~ (B~) a woven fabric based on
fibres of polyolefines or o~ the chemical species mentioned
under Al,or o~ (C~) a ~mposite o~ a woven fabric and a non-
. woven, the two const.ituents conslsting of ~ibres of identical
or di~ferent chemical composition o~ the type mentioned under ~'.
. - 5 _
.
~ 3~ ~
Furthermore, it is possible to assembleJ by needle-punching,
gluing or high frequency welding, non-woven webs of different gauges and
above all webs of non-wovens and of woven fabrics, in order to achieve
superior tensometric properties.
The binder is based on a modified or unmodified bitumen but is
sufficiently fluid between 125C and 160C to permit fine dispersion of
the sulphur between these temperatures. Preferably~ the average size of
the sulphur particles in the emulsion is about 0.5 to 5 microns. The
proportion of sulphur in the binder is chosen in accordance with th~
required properties of the impermeable sheet and the ease of impregnation
of the fibrous material. The binder can be modified by adding solvents,
fluxes, fillers, inorganic and organic pigments or dyestuffs, herbicidal
or fungicidal compounds or the like.
To manufacture the binder it is essential to proceed as described
in French Patent No. 2,230,691. In this way a fine emulsion of the liquid
sulphur in the liquid or pasty bitumen is obtained, with sulphur droplets
the size of which does not exceed 10 microns and is in practice between
0.5 and 5 microns.
The impregnation can be carried out either on dry fibrous
materials or on ~he same materials when wet, but treated beforehand with
a specific adhesion promoter for the fibres constituting thenon~woven or
the woven fabric. This adhesion-promoter has the effect of repelling the
water from the fibres of the material, so as to allow contact with the
-- 6 --
.... .
7~63~
bitumen; it consists,preferably,either of the acetate of a
secondary arnine or of a suspension of quaternary amine in
coal tar oil,either ma-terial being in a 1 : 10 aqueous
suspension and being sprayed onto the fibrous material at the
S rate of abou-t 40 g per m . As an example o~ an ~dhesion
promoter of the secondary amine acetate type, there may be
mentioned the alkyldipropylenetriamines of the formula
R-NH-(CH2)3-NH-(CH2)3-NH2, in which R represents a long-chain
aliphatic radlcal.
The impregnation of the fibrous material can be
carried out at a temperature of about 130 to 140C, by
spraying9 by dipping or by coating. Spraying is carried
out at a temperature of about 140C and under a presst~e
between 4 and 6 bars, throu~h special vortex nozzles.
These nozzles are mour.ted on a frame with constant spacing
of the nozzles, so chosen as to ensure good transverse
distribution. This frame is of the double-wall heated
~rame type. The material is delivered either by means
of a constant pressure of a neutral gas or by means o~ a
metering pump or by a system of a pump and discharge valve~.
The ~rame is placed 40 cm above the material to be treated.
For impregnation by dipping, the fibrous material is
passed through one or more troughs containing the binder
and kept at a ternperature of 135 to 145C~ In certain
cases, it is preferable to carry out the impregnation by
coating, at a temperature of 125 to 145C. ~arious conventional
coating techniques, such as knife coating, can be used for
this purposeO
-- 7 --
~L~7463~ ~
, .. ..
- In order to facilitate the subsequent unwinding of
the covering sheet, when it is being applied, the sheet can
be provided with a non-adhesive protective film as the last
stage of the manufacturing process.
Using the bitumen/sulphur binder described above
results in the following advantages:
Firstly, a lowering of the use temperature, due to
the fluxing or fluidising power of the sulphur which, at the
same time, permits better penetration o~ the binder into the
interior of the fibrous material; and
secondly, progressive crosslinking, due to the partial
crystallisation of the sulphur, which reduces the sensiti~ity
of the binder -to rises in temperature and consequently a~oids
migration of the binder both inside the ~ibrous materi&l and
at the sur~ace.
A microscopic study of the sheet manufactured according
to the invention, bea~ing on the question of crystallisation
in a bitumen/sulphur medium s in effect shows a genuine
entangling between the fibres or filaments and the crystallites
~see the attached ~igure; a) Eibres or filaments, b) entangled
cystallised materials3.
In practice, it has been found that the phenomena G~
migration of the blnder on the fibrous material are greatly
reduced from the start of applying the sheet and completely
eliminated after a few hours, as a result of the crystallisa- -
tion of the sulphur between the fibres. The entangling
which results therefrom imparts to the covering sheet a
homogeneous structure and a high degree o~ cohesion, which
- 8 -
.. . .
'
1~79L631
manifest themselves in increased flexibili-ty and increased
mechanical strength.
On the other hand 9 the lowering of the viscosity at
a given temperature makes it possible -to impregnate the
fibrous material at temperatures which are sufficiently low
not to damage the material and which can even come down -to
about 125C. Furthermore, it thus becomes possible to
place the binder under high pressure (4 to 6 bars) without
causing it to deteriorate, which makes it possible to spray
the ~ibrous material under high pressure and hence to manu-
facture the covering shee~ on site.
The required widths can be assembled either by over-
lapping or by applying a join~ covering strip, that is to
say a strip of the same type applied onto the contiguous
ends of the widths.
The new covering sheets self-adhere to one another
under pressure in the cold,at a temperature of 16C or above,
as a re~ult o~ the fluxing effect of the sulphur in the binder.
This property makes it possible to avoid the use of glue or
~0 the application of a large amount of hea-t for joining up the
widths.
Summarising, the covering sheet ob~ained according to
the invention is distinguished, in respect of its manufacture
and its application, by the fact that it can be prepared at
a relatively low temperature and on site (as a result of the
stability of the binder, whish withstands high pressure
spraying) and that it is self-adhesive to itself in the
cold. As regard its ef~ects, the new sheet exhibits complete
~Ltl 74631
impermeability to wa-ter, coupled wi-th the absence of migration
of the binder when the material is applied in positions other
than horizontal, and remarkable adaptation to deformation of
the carriers to which it is applied,whether this deformation
be shearing, punching 9 flexing, bursting, tearing or tension.
It mus-t be emphasised here that the process according
to the invention makes i-t possible to employ any bitumen,
that is to say it is not limited to soft bitumens. In fact,
so~t bitumens have already been used to impregnate fibrous
lo materials of all kinds at relatively low temperatures, of
about 140C, but the productsthus obtained did not exhibit
fully satisfactory mechanical strength properties, which con-
. .
sequently limited their use; only applications where theseproducts were not exposed to major mechanical forces were
possible. On the other hand, it was also known to impregnate
certain fibrous materials with hard bitumens; in this way,
impermeable membranes exhibiting excellent mechanical proper-
ties were obtained. However, the need to work at rela-
tively high temperatures, of about 200C, limited the use of
the hard bitumens to fibrous materials having higher melting
points or decomposition points; ~urthermore, it created
difficulties, which were sometimes considerable, when the
material was applled.
Surprisingly, the process according to the invention
now makes it possible to achieve what has hitherto been proved
impossible, namely to manufacture, from soft bitumens, imperme
able sheets possessing very high mechanical strength9 but also
to use hard bitumens at lower temperatures and thus to impreg-
-- 10 -- : .
3 ~7~63~
nate fibrous materials of all kinds without danger of damage tothe material and without difficulties when the material is
applied. This result constitutes a doubly remarkable technical
advance; it is obviously due to the use of the particular binder
described above. However, it was not to be expected that the
recrystallisation of sulphur within the sheet, after application
and cooling, would manifest itself in a decisive improvement of
the mechanical properties, and, furthermore, it was not possible
to foresee that the addition of sulphur to hard bitumens would
exert a fluxing effect such that the use temperature was as a
result lowered by about 60 to 80C.
The covering sheet described above makes it possible to
produce main (water) barriers, barriers to trickling water, or
semi-permeable membranes, for civil engineering work or building
work, below or above ground and, furthermore, to provide a rein-
forcement effect or support effect for certain parts of the work.
In particular, it makes it possible to produce relnforcements
suitable for various structures employed in civil engineering
and in building, ensuring the impermeability and bonding of the
various layers which constitute the structures.
The mechanical strength of the structures is improved,
and durable carrier layers and bonding layers can be produced.
In the examples which follow, the products usually
sold commercially were used as fibrous material. Soft bitumens
are to be understood as bitumens having a high penetration value
(for example 80-100, 100-120 or 180-200), whilst hard
--11--
7463~L
bitumens are to be understood as bitumens having a low pene-
tration value (for example 20-3Q or 40-50).
The fibrous material is a nonwoven of continuous
~ilaments based on polyamide 6,6; filament gauge: 15 dtex;
weight of the web after needle~punching: 350 g/m2. For
results of the tests, see Table I below. In this table,
as well as in the ~ollowing tables, the abbreviation ESB
~0:70 denotes an emulsion of sulphur in bitumen in a weight
ratio o~ 30 to 70, whilst the entry 80-100 defines the type
of bitumen employed.
Example_2
The fibrous materials isanonwoven of continuous fila-
ments double-component fibres) of polypropylene and
polyamide in-a weight ratio of the two components of 70 to
30. The filam~nts are bonded to one another by heat-bonding,
effeoted in a heated calender; the ~inal web weighs 250 g/m2.
For the results of the tests, see Table II.
Example 3
The fibrous materialsis a nonwoven of short ~ibres,
o~ gauge 2 dtex, based on polyvinyl chloride ~Clévyl T, registered
trademark o~ Rh~one-Poulenc Textiles); weight of the web after
needle-punching: 260 g/m . For results of the tests, see
Table III.
~
The fibrous material is a glass mat weighing 450 gSm
For results of th~ tests, see Table IV.
A glass mat is to be understood as a ~elt of glass
- 12 -
11~37~63~L
fibres, cut to 25 and 50 mm length and agglomerated
by means of a binder. It serves to produce laminates
possessing average mechanioal strength, without preferential
orientation of the fibres.
Example 5
The fibrous ma-terial is a woven fabric consisting of
short fibres of polyester; weight of fabric 130 g/m2. For
results of the tests, see Table V~
The ~ibrous material is a woven fabric based on yarns
composed of short fibres of polyamides 6,6; weight of fabric
130 g/m2. For results of the tests, see Table VI,
~, .
The fibrous material is a composite of a non-woven
lS of continuous ~ilaments of polyester - filament gauge 8 dtex,
weight of the web: 350 g/m29 and of a woven fabric based on
yarns composed of continuous filaments of polypropylene -
weigh-t of the fabric: 115 g/m2. The non-woven web and the
woven fabric are bcnded to one another by needle-punching.-
For results of the tests, see Table VII.
~e~.~
The fibrous material is a needle-punched non-woven,
of continuous filaments of polyester - filament gauge 8 dtex,
weight of the web: 300 g/m2. For results of the tests~ see
Table VIII.
1~74~i31
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~74631
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-- 21. _
