Note: Descriptions are shown in the official language in which they were submitted.
CA 02594439 2007-07-23
FLOOR COVERING
Field of the Invention
The invention relates to a floor covering with high slip resistance, which
essentially includes a web or sheet shaped base material of an elastomeric
material with an
anti-slip surface including granular particles.
Background Art
A floor covering of the generic type is known from WO 03/100162. This floor
covering includes a carrier made of plastic, preferably a thermoplastic
polymer or a
thermoplastic elastomer. To increase the slip resistance, the surface of the
carrier is
roughened by way of granular particles. These granular particles include
preferably hard
particles of quartz, silicon carbide, aluminum oxide and/or sand paper.
It is a disadvantage of this known floor covering that it is hard to cut
because of the
very hard particle material (corundum problem). This creates problems in the
confectioning and/or further processing of the floor covering.
Summary of the Invention
It is an object of the invention to provide a floor covering which is
distinguished by
a high slip resistance and in addition is easily and economically manufactured
and
processed.
This object is achieved with a floor covering in accordance with the invention
with
high slip resistance. The inventive floor covering includes an essentially web
or sheet
shaped base material of an elastomeric material. The surface of the floor
covering is
roughened by way of granular particles and provides an anti-slip effect. In
accordance
with the invention, the granular particles are made of a polymeric material,
the hardness of
which is higher than that of the elastomeric material.
It has been surprisingly found that these materials, although they are
significantly
softer than mineral particles, for example corundum, and additionally have a
tendency for
rounded rather than sharp corners, nevertheless result in a high slip
resistance. However,
in contrast to the floor coverings with mineral particles, they have the
advantage of ease of
manufacture and further processing. In particular, a floor covering in
accordance with the
invention can be cut very well.
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CA 02594439 2007-07-23
It has been found that good results with respect to the anti-skid effect are
achieved
already when the hardness of the polymeric material is by 10 shore D higher
than that of
the elastomeric material.
Thermoplastics and duroplastics can principally be used as the polymeric
material.
Both materials can be mixed into the base material, for example in the form of
particles.
Duroplastics are less suitable for a spreading-on application, since they,
just like the
corundum particles known in the art, can sink into the base material during
its
vulcanization and resulting liquefaction.
Suitable thermoplastic polyrners for mixing with the base material are
generally
those, which have a melting point higher than the high temperatures occurring
during later
processing steps. Thermoplastic polymers with lower melting points can also be
used if
shear forces which could lead to a mixing of the materials are prevented
during later
processing steps. The melting itself of the particle material is not a problem
as long as the
particle droplets as such remain intact. As long as no shear forces occur,
this is generally
already guaranteed because of the highly different viscosities of the
materials.
Preferably, semi-crystalline thermoplastic polymers are used.
In the case of spread-on particles of semi-crystalline thermoplastic material,
it is
even desirable that the particle material melt during the vulcanization of the
base material,
in order to float up to the surface of the latter. The particle droplets
thereby remain intact
at the surface during the vulcanization and do not sink into the liquefied
base material.
After cooling, the particle droplets re-crystallize into grainy particles.
This property can be described by the location of an exothermic melting peak
maximum of the thermoplastic polymeric material in a thermogram measured with
a
Differential Scanning Calorimetry (DSC) process. It has been found that for
the elastomers
and processes commonly used for the floor coverings, those thermoplastic,
preferably
semi-crystalline, polymers are especially suited, which in a test in the
Differential
Scanning Calorimetry (DSC) according to DIN 53765 have an exothermic melting
peak
maximum in the thermogram in a temperature range of 100 C to 250 C. If the
melting
point is in the temperature range given, the thermoplastic polymer during the
vulcanization
of the base material melts to a drop, which in the case of the spread-on
particles does not
sink into the base material, but floats at the surface. Subsequent to the
vulcanization
process, the drop at the surface re-crystallizes into a granular particle. The
anti-slip
properties remain intact.
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The person skilled in the art will be able to select a respectively suitable
thermoplastic polymer for a given elastomeric base material and manufacturing
process
without any further detailed description.
Generally, the thermoplastic polymers can be, for example, pure homopolymers,
or
copolymers or grafted homo or copolymers. They preferably include
thermoplastic
polymers selected from the group of polyofefins, modified polyolefins, semi-
crystalline
polyamides and/or polyesters. The polymers used can also be grafted, for
example, with
conventional grafting compounds such as maleic acid anhydride and/or acrylic
acid, in
order to improve the binding of the particles into the matrix.
A floor covering in accordance with the invention can be manufactured in
different
ways. For example, the granular particles can be simply spread, as mentioned
above, onto
the un-vulcanized blank of the elastomeric web and subsequently subjected
together with
the blank to a heat treatment for the vulcanization, whereby the particles are
preferably
melted as well.
It is also possible, as also mentioned above, to mix the granular particles
into the
base material of elastomeric raw material. In this variant, granular particles
can be spread
in addition onto the surface, whereby the process is then continued as
described above.
In a further variant, the blank of the base material web made of elastomeric
raw
material to which the granular particles were admixed is split and
subsequently subjected,
optionally after spreading-on of additional particles, to a vulcanization
process. In this
process variant, it is also preferable to use a thermoplastic, preferably semi-
crystalline
polymer for the admixed particles, which after splitting of the base web also
come to lie at
the surface of the split web to a certain degree, which polymer in the range
of the
vulcanization temperature of the elastomeric base material melts, in order to
also prevent a
sinking of these particles into the base material during the vulcanization.
The admixing of the granular particles has the advantage compared to the
spreading-on that a floor covering produced in this manner has a higher wear
resistance
and therefore a longer service life. Furthermore, it allows for the
manufacture of a floor
covering by splitting of a base web.
In the case of the admixing of the granular particles one must bear in mind
that
these mixing processes are generally carried out at temperatures between 100
C and 130
C. The melting temperature of the thermoplastic polymer used for the granular
particles,
which is defined, as described above, by the location of the exothermic melt
peak
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CA 02594439 2007-07-23
maximum of the material, should therefore preferably be > 130 C. Further
processing
steps can also be carried out at temperatures higher than the melting
temperature of the
thermoplastic polymer, as long as it is assured that no shear forces act on
the materials at
these temperatures, which could lead to a mixing of the particle material with
the base
material.
The requirements for the grain sizes and amount of the particle material
differ
depending on the type of manufacture of the floor covering in accordance with
the
invention. It has been found that, in the case of a spreading on of the
granular particles,
the best anti-slip properties are achieved when the mean grain size of the
particles,
measured by sieve analysis according to DIN 66165, is between 100 m and 800 m,
preferably about 300 m. The anti-slip properties degrade too much at grain
sizes of <100
m, while for the flooring thicknesses of 2-5mm common for elastic floor
coverings, the
mechanical and fire safety properties degrade too much at grain sizes >800 m.
The amount of spread on particles per surface area of the base material should
be
between 30cm3/m2 and 360cm3/mZ, preferably between 100cm3/m2 and 250 cm3/mZ.
The
anti-slip properties decrease too much at amounts below 30 cm3/m2, while the
danger
exists that the mechanical and fire safety properties of the floor covering
deteriorate too
much at amounts above 360 cm3/m2.
In the case of an admixing of the granular particles, the mean grain size of
the
particles, measured by sieve analysis according to DIN 66165, should be
between 100 m
and 2000 m, preferably at about 500 m. At grain sizes below 100 .m the anti-
slip
properties again degrade too much, while the mechanical and fire safety
properties
degrade, as in the above cases at grain sizes above 2000 m.
The portion of the admixed particles is thereby preferably between 10% and 40%
of the volume of the base material, preferably between 14% and 25%. At a
portion of less
than 10%, the anti-slip properties decrease too much and the mechanical and
fire safety
properties degrade at a portion of more than 40%.
Potential elastomers for the base material are those which are suited for use
as a
floor covering. The base material preferably includes one or more of the
elastomers SBR
(poly-styrol-butadiene-caoutchouc), NBR (nitrile-butadiene-caoutchouc), EPM
(ethylene-
propylene-caoutchouc), EPDM (ethylene-propylene-diene-caoutchouc), EVA
(ethylene-
vinylacetate), CSM (chlorosulfonyl-polyethylene-caoutchouc), VSi (silicone-
caoutchouc)
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and/or AEM (ethylene-acrylate-caoutchouc), whether sulfur cross-linked,
peroxide cross-
linked and/or addition cross-linked.
In a floor covering in accordance with the invention, the base material may
further
include generally known mineral type fillers, for example, clay, chalk,
silicic acid and/or
silicic chalk. These fillers are used for the purpose of adjusting the
physical properties, for
example the hardness and the wear of the rubber compound. Furthermore, fillers
are also
used for improvement of the fire safety properties. Normally, they are added
in amounts of
10-70%/wt with grain sizes of <100 m.
A floor covering in accordance with the invention can be used in web or sheet
form.
The invention will now be further described in the following with reference to
exemplary embodiments.
Exemplary Embodiment I
275cm3 of a polypropylene powder with a mean grain size of 300 m was spread
per m2 onto a web shaped base material of a sulfur cross-linkable SBR mixture.
The
maximum of the melting peak of the polypropylene powder determined by DSC
according
to DIN 53765 was 163 C. The web with the spread-on powder was subsequently
subjected for a period of 5 min and at 180 C to a vulcanization process in a
continuous
vulcanization installation with a band press. The result was an elastomeric
floor covering,
which in a slip test with a British Pendulum Tester (BPT) achieved a slip
safety value of
40 scale units upon testing with water as the glide medium.
Exemplary Embodiment II
40%/volume of the above powder was mixed at an expulsion temperature of 120
C with a sulfur cross-linkable SBR mixture. A blank of this material was
calendared and
split in the centre and the resulting blank was subjected for a period of 7
min and at 180 C
to a vulcanization process in a non-continuous vulcanization installation. The
resulting
elastomeric floor covering, achieved in the above described test a slip safety
value of 36
scale units upon testing with water as the glide medium.
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Exemplary Embodiment III
In a third variant, a web was calendared from the mixture with polypropylene
powder as described in exemplary embodiment 2 and another 275cm3 of the same
polypropylene powder was spread per m2 onto this web. The web was then
subjected for a
period of 5 min and at 180 C to a vulcanization process in a continuous
vulcanization
installation with a band press. The result was an elastomeric floor covering,
which in the
above described test method achieved a slip safety value of 40 scale units
upon testing
with water as the glide medium.
Comparative Example I
A web shaped base material of a sulfur cross-linkable SBR mixture analogous to
Example 1, but without applied powder, was subjected for a period of 5 min and
at 180 C
to a vulcanization process in a continuous vulcanization installation with a
band press. The
resulting elastomeric floor covering achieved a slip safety value of only 12
scale units
according to the above described testing method upon testing with water as the
glide
medium.
Comparative Example II
In a further comparative experiment, 800g/m2 of corundum particles were spread
onto a web shaped base material of a sulfur cross-linkable SBR mixture
analogous to
Example 1, and subjected for a period of 5 min and at 180 C to a vulcanization
process in
a continuous vulcanization installation with a band press. After
vulcanization, the majority
of the corundum particles were sunken into and enclosed by the base material.
The
resulting elastomeric floor covering achieved a slip safety value of only 14
scale units
according to the above described testing method upon testing with water.
The above exemplary embodiments show that a floor covering in accordance with
the invention has a significantly improved slip safety value compared to a
covering
without anti-slip surface and a covering with spread-on corundum particles.
In addition, the floor coverings made according to exemplary embodiments 2 and
3
with admixed granular particles of polypropylene were distinguished by a more
than 20%
increased wear resistance, when compared to the base material used in
exemplary
embodiment 1 without corresponding admixture, according to a test carried out
under ISO
9352 (Taber-Scoring) on the floor coverings of the exemplary embodiment.
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