Note: Descriptions are shown in the official language in which they were submitted.
109093~
This invention relates to thermoplastic materials and their use for
the production of mouldings, particularly web and sheeting, having low water
vapour permeability and at the same time low water absorption.
It is known that thermoplastic materials may be used for example in
the form of web or sheeting for sealing against moisture. They may be united
either by heat sealing or by a swelling agent or special adhesive to form
larger sealing surfaces and either laid loosely on the substructure of, for
example, concrete, wood, bitumen or air-containing thermal insulating material
or stuck all over or at isolated places by special sheet a& esives to the said
substructure.
To provide a seal against flowing or static water a thickness of the
material of from 1 to 2 mm and the presence of a closed surface are sufficient.
Particularly in building construction, for example in sealing flat roofs, there
are used for keeping the necessary layers of thermal insulation dry so-called
vapour-lock sheeting which has to have a specific minimal resistance to the
diffusion of water vapour. It is important that the sheeting which insulates
the thermal insulating layer from the moisture of the building has a lower
water vapour diffusion than the sealing membrane situated above the thermal
insulation for protection against rain. This precludes accumulation of mois-
ture in or on the thermal insulation layer and consequent loss or diminution
of its function.
It is however often required of sheeting or web used for insulating
purposes that it should have - in addition to low water vapour permeability -
a low water absorption because the durability behaviour and the life in rela-
tion to the corrosive aqueous liquids encountered in some environments of use,
for example in structural work below ground, is considerably better in the
case of low water absorption.
It is therefore an object of the invention to develop a thermoplastic
material which, particularly in the form of web or sheeting, has a good water
vapour permeability and at the same time a low water absorption. Moreover it
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1090934
should naturally have the properties which are essential in any case for the
use of such material for the production of insulating web or sheeting, namely
favourable rheological behaviour, good heat-sealing properties, adequate
mechanical properties and also resistance to the effects of weathering and
aggressive media and thermo-mechanical influences at high and low temperatures.
According to the invention, there is provided a thermoplastic ma-
terial which consists of:
(a) 100 parts by weight of a polyolefin rubber;
~b) from 15 to 50 parts by weight of a crystalline or partly crystalline
polyolefin;
(c) from 30 to 140 parts by weight of a carbon black;
(d) from~ to 150 parts by weight of a bitumen or mineral oil; and
~e) froml~ to 360 parts by weight of chalk or siliceous chalk.
Within the scope of the present invention the polyolefin rubber
which forms the basis of the thermoplastic material according to the invention
may be a polymer prepared from ethylene, one or more ~-olefins of three to
eight carbon atoms, particularly propylene, with or without one or more multi-
olefins by means of a Ziegler-Natta catalyst which may additionally contain
an activator and a modifier, in solution or dispersion, at a temperature of
from -30C to +100C, for example by the method of DT-OS 1,570,352, 1,595,442
or 1,720,450 and also DT-OS 2,427,343.
Polyolefin rubbers are preferred which are saturated and consist of
15 to 90% by weight and more preferably 30 to 75% by weight of ethylene and
85 to 10% and more preferably 70 to 25% by weight of propylene and/or butene-
(1) or are unsaturated and consist in addition to ethylene and propylene or
butene-(l) of a multi-olefin, namely in such an amount that 0.5 to 30 double
bonds are contained per 1000 carbon atoms in the rubber. Particularly pre-
ferred multi-olefins include cis-hexadiene-~1,4), dicyclopentadiene, 5-
methylene-2-norbornene, 5-ethylidene-2-norbornene and 5-isopropylidene-2-
norbornene.
109093~
Polyolefins which are added to the material according to the inven-
tion in an amount of from 15 to 50 parts by weight and preferably from 20 to
40 parts by weight include first of all a crystalline or partly crystalline
modification of polyethylene having a density of from 0.910 to 0.975 g/cm3,
an RSV value (measured at 135C in decalin (decahydronaphthalene)) of from
0.5 to 3.3 dl/g and a melt index of from 0.2 to 50 g/lnmin. It is possible
however to use partly crystalline copolymers of ethylene with another -olefin
within the limits of the said specification. Also suitable are crystalline
and partly crystalline homopolymers and copolymers (with other ~-olefins and
preferably with ethylene) of propylene or butene-(l), namely homopolymers and
copolymers of propylene having densities of from 0.90 to 0.910 g/cm3 RSV va-
lues (measured at 135C in decalin) of 1.0 to 10 dl/g and melt indices of 0.1
to 50 g/ln min, and homopolymers and copolymers of butene-(l) having densities
of from 0.910 to 0.925 g/cm3, RSV values (measured at 135C in decalin) of 1.0
to 10 dl/g and melt indices of 0.1 to 100 g/10 min.
To improve the heat-sealing properties of mouldings prepared from
the material according to the invention it is also possible to use - in addi-
tion to the crystalline and/or partly crystalline polyolefins - a small amount
(up to about one-third of the weight of the crystalline and/or partly crystal-
line polyolefin) of atactic polypropylene and/or polybutene-l having a density
of 0.86 g/cm3 and RSV values (measured at 135C in decalin) of 0.1 to 3.0 dl/g
Suitable carbon blacks include those prepared by the furnace method,
especially of the types FEF (fast extruding furnace black), GPF (general pur-
pose furnace black), HMF (high modulus furnace black) APF (all purpose furnace
black), HAF (high abrasion furnace black), FT (fine thermal black), MT (medium
thermal black) and SRF (semi-reinforcing furnace black). The carbon blacks
are added to the material according to the invention in an amount of from 30
to 140 parts by weight and preferably from 40 to 120 parts by weight. The
materials also include as further filler from 3 to 360 parts by weight, gene-
30 rally from 3 to 350 parts by weight and preferably from 30 to 300 parts by
1090934
weight, of chalk and/or siliceous chalk. These include natural, ground pig-
ments containing mainly calcium carbonate and/or silicic acid or precipitated
calcium carbonate which may have been coated for example with a fatty acid
derivative, in the form customarily used in processing rubber.
Finally the material according to the invention includes from 5 to
150 parts by weight, generally from 5 to 120 parts by weight and preferably
from 25 to 100 parts by weight of a bitumen or mineral oil.
Suitable bitumens include liquid to solid distillation residues from
petroleum refining consisting mainly of highly condensed hydrocarbons; their
structure may be partially changed for example by oxidation (blown bitumens).
Suitable mineral oils are those having viscosities of from 50 to
5000 centistokes at 20C and preferably of from 200 to 3000 centistokes at
20C and a density of 0.84 to 0.98 g/cm3. The oils may contain paraffinic
carbon atoms and also naphthenic or aromatic carbon atoms.
Production of the claimed thermoplastic material may be carried out
for example in a commercial internal mixer with floating weight, with or with-
out heating. The period required for homogenisation depends on the formula-
tion, the structure of the starting material, the constructional features of
the mixi~g plant and of the further processing units and the process conditions
20 chosen such as temperatures of the material (generally from 50 to 220C and
preferably from 80 to 150C), the extent to which the internal mixer is filled
(generally from 1.0 to 1.8 and preferably from 1.2 to 1.5 based on its effec-
tive volume) and the speed of the rotor (generally up to 100 and preferably
from 10 to 40 rpm) and is generally from 1 to 100 minutes and preferably 35
minutes. After adequate homogenisation the material, usually having a tempera-
ture of from 50 to 220C, is discharged. In the case of mixtures containing
a high concentration of bitumen it may be necessary in order to preclude con-
siderable adhesion to casing and rotors (which may prevent substantially the
discharge of the material) to cool the same prior to the discharge (cooling
30 period from 1 to 30 minutes and preferably from 3 to 15 minutes).
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1090934
The material discharged from the internal mixer is then converted
into strips or strings for example through a pair of rollers or a unit driven
by a screw and either granulated or transferred immediately to a further pro-
cessing unit.
This further processing unit which serves particularly for the pro-
duction of the web or sheeting may be for example a calender, an extruder
with a flat sheeting die or so-called roller-head plant. It may be provided
with means for applying or introducing carrier materials, as for example fleece
of synthetic fibres and glass cloth.
The material according to the invention which is distinguished by
good water vapour permeability and at the same time low water absorption and
which is also distinguished by good strength at elevated temperatures may be
used, especially in the form of web or sheeting, both in superstructures for
example for sealing buildings having flat roofs and in substructures for ex-
ample for linings for collecting basins, keeping tanks, settling tanks~ stor-
age basins and for laying out pools, canals and artificial lakes. Other
applications are as a sealing sheeting for breaches, tunnels, subways and
underpasses and for bridge building and skyscraper sealing in areas of subsoil
water.
The following Examples serve to illustrate the present invention.
Example 1
In a laboratory kneader having an effective volume of 2 litres of
the Werner ~ Pfleiderer GK2 type with a ram there are mixed the ethylene-
propylene-diene rubber identified as EPDM I (diene = ethylidene nor~ornene;
30% by weight of propylene; 8 double bonds per 1000 carbon atoms; MLl+4 (at
100C~ = 87; polymer crude strength = 130 kp/cm2) with the following products
according to the stated mixing periods at a temperature of 90C at the outlet
from the kneader and a rotor speed of 50 rpm.
1090934
Mixing procedure: Time (minutes)
introduction of 703 g of EPDMI 0
introduction of 703 g of bitumen B 85/25
introduction of 633 g of FEF carbon black
introduction of 1407 g of chalk
introduction of 211 g of polyethylene
~density 0.945 g/cm3, RSV 1.45 dl/g, 3
melt index 7 g/10 min)
ram cleaned 4
discharge 9
The homogeneous material is discharged with a material temperature
of 150C and then converted on a laboratory roll mill having a surface tem-
perature of 50C into a rough sheet which is cut into strips or granulated.
The strips or granules are converted into web of a thickness of
1 mm in a Kleinewefer laboratory extruder with a flat die 300 mm in width
arranged in front and a two-roll smoothing calender arranged behind. Portions
taken from this web are investigated according to DIN 52122 for water vapour
permeability and according to DIN 53495, method A, for water absorption. The
water absorption after a storage period of 24 hours is 0.15% and after 200
hours is 0.25% by weight. The water vapour permeability resistance factor,
calculated according to DIN 52615 is ~ = 145,000.
Example 2
Example 1 is repeated with the difference that 1407 g of siliceous
chalk is used instead of chalk and the material is discharged at a material
temperature of 160C. Strips also prepared as described in Example 1 are
shaped into web on a 4-roll laboratory calender. Test boards prepared there-
from are measured according to the DIN test methods given in Example 1
Water absorption after 24 hours: 0.3% by weight.
Water absorption after 200 hours: 0.6% by weight.
Water vapour permeability resistance factor: 105,000 ~.
1090934
Example 3
Thermoplastic material is prepared under the conditions specified
in Example 1 from the components set out below and prepared within the times
specified:
Mixing procedure: Time (minutes)
introduction of 964 g of EPDM I 0
introduction of 1284 g of SRF black
introduction of 268 g of naphth. mineral oil)
introduction of 428 g of polyethylene 3
~density 0.923 g/cm3, melt index 8 g/10 min)
ram cleaned 4
discharge 9
The discharge temperature of the material is 155C. Production and
testing of the strips is carried out under the conditions specified in Example
1. The water absorption of the test specimens prepared according to the Ex-
ample is 0.25% by weight after 24 hours and 0.6% by weight after 200 hours.
The water vapour permeability resistance factor is ~ = 100,000
Example 4
Under the same conditions as in Example 1 the following mixing com-
ponents are mixed in the specified times and in the specified proportions to
form a thermoplastic material.
Mixing procedure: Time ~minutes)
introduction of 1096 g of EPDM I
O
introduction of 261 g of bitumen B 80
introduction of 1253 g of SRF black)
introduction of 417 g of chalk
introduction of 209 g of polyethylene 3
~density 0.935 g/cm3, melt index
0.5 g/10 min)
ram cleaned 4
discharge 9
The discharge temperature of the material is 160C. The test values
1090934
for water absorption ascertained under the same conditions as in the previous
Examples are 0.3%/0.8% by weight after 24/200 hours. The value 120,000 is
determined for the water vapour permeability resistance factor ~.
Example 5
The following mixing components as stated are mixed together under
the conditions specified for Example 3:
Mixing procedure: Time (minutes)
introduction of 1000 g of EPDM II 0
introduction of 1000 g of SRF black
introduction of 450 g of polyethylene 3
~density 0.923 g/cm3, melt index
8 g/10 min)
ram cleaned 4
discharge 9
The EPDM II used here differs from EPDM I by a MLl+4 value of 45
and a polymer crude strength of 50 kp/cm2. The discharge temperature of the
material is 158C. Water absorption and water vapour permeability are deter-
mined analogously to Example 3. Water absorption after 24 hours is 0.28% by
weight and after 200 hours is 0.7% by weight. The water vapour permeability
resistance factor is ~ = 114,000.
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