Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02143469 1999-12-21
MULTI-COLOURED, PATTERNED FLOOR COVERING
The invention relates to mufti-coloured, patterned floor coverings made of
rubber.
More particularly, the invention relates to floor coverings consisting of a
cautchouc
(elastomer) base web and a contrastingly coloured cautchouc (elastomer)
granulate which
is pressed flush at least into the surface of the base web and is subsequently
permanently
fixed tr.erein by vulcanization of the material of the resulting product. The
individual
particles of the granulate have at least two particle sections which are
different in colour
from each other and from the base web.
A floor covering of this general type is described in German Patent
Application
SN 44 O5 589.7 and includes a base web of a first colour and contrastingly
coloured
particles which are embedded into the base web. The base web and the particles
are made
of a cross-linkable, elastomeric material. The contrastingly coloured
elastomerer granulate
is pressed flush into the surface of the base web and is permanently fixed
therein by
subsequent vulcanization of the resulting base/granulate combination. The
individual
contrastingly coloured particles have particle sections which are different in
colour from
each other and from the base web.
In this prior floor covering, the amount and colour of the granulate particles
and
their particle sections is selected and coordinated with the amount and colour
of the base
web material in such a way that the blended colour achieved upon a homogeneous
mixing
of all components in the floor covering is the same as the first colour of the
base web. A
process for the manufacture of the granulate particles and their differently
coloured
particle sections disclosed in that prior application as well as a method for
embedding
them into the base web.
tt is a disadvantage of this prior floor covering that the colours of the
particles
spread onto the base web must be selected such that the blended colour
achieved upon a
homogeneous mixing thereof is the same as the base web colour. This
requirement
severel~~ limits the range of colours available for use in such a floor
covering. The range
of possible colour designs which can be created in such a floor covering is
therefore
substam:ially limited. Furthermore, it is impossible to render that floor
covering
conductive by incorporating soot into the base web, because of these
limitations with
respect to granulate colour.
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CA 02143469 1999-12-21
The present disclosure is of a floor covering of the above general type, which
gives
the des igner more freedom in selecting the colour design of the floor
covering and thereby
providers for an improved optical appearance. The disclosure also provides an
electrically
conductive variant with a wide range of possible colour patterns.
In particular, at least a first particle section of each granulate particle
has strip or
wedge shaped portions which extend through at least a second particle section.
Furthermore, the differently coloured particle sections have the same colours
in at least
50% of the particles of each granulate visible in the surface of the floor
covering and have
respective surface areas n. If two colours 1 and 2 are present in each
granulate, then in the
at least 50% of the particles with equally coloured particle sections the sums
of the areas n
of the r~apective colours follow the following equation:
ff colours 1,2,3...x, are present in each granulate, the sums of the areas n
of the
respective colours in the at least 50% of the particles with equally coloured
particle
section~~ follow the formula
More particularly in accordance with the invention there is provided,
multico loured, patterned floor covering, comprising a base web of material
having a first
colour, ;end at least one contrastingly coloured granulate which is first
pressed flush into a
surface of the base web and subsequently fixed therein by vulcanization of the
resulting
product the web and the granulate being made of a crosslinkable, elastomeric
material;
individual particles of the granulate having at least two particle sections
which are
coloured different from each other and from the first colour; in the granulate
particles,
strip or 'wedge shaped portions of at least a first particle section extending
through at least
a second particle section and the differently coloured particle sections have
the same
colours in at least 50% of the particles of each granulate visible in the
surface of the floor
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CA 02143469 1999-12-21
covering and have respective surface areas n; wherein when the granulate
includes two
colours l, 2, the sums of the areas n for each colour follow the formula
nz
;rnd when the granulate includes more than two colours 1, 2,....x, the sum of
the
areas n follows the formula
and where the amount and colour of the particles and the particle sections
have
been selected in relation to the amount and colour of the material of the base
web so that a
blended colour can be achieved upon homogenous mixing of all components in the
floor
covering; which does not correspond to the first colour.
'fhe aesthetic appearance of such a floor covering can be varied to a much
greater
extend than is possible with the prior art floor coverings described above.
The colours for
a floor covering in accordance with the invention can be selected almost
arbitrarily and
one is only limited by aesthetic criteria. The range of possible designs is
thereby
significmtly extended, since it is possible to achieve any colour effect in
the overall
appearance.
',he use of elastomeric materials for all floor covering components provides
the
new floor covering with excellent mechanical properties. The properties of the
floor
covering are easily controlled since the body of the floor covering, which is
provided by
the base web, is of homogeneous consistency and completely encloses the
particles
embeddv.d therein at least below the surface of the flooring.
7'he particles can be so tightly spaced in the new floor covering that they
mutually
contact. In such an embodiment, the overall appearance of the floor covering
is mainly
determined by the structure and colour of the particles. However, it is also
possible to
embed the particles into the base web in a spaced apart arrangement. The
overall
appearance of the floor covering is then determined essentially by the colour
of the base
web, whereby the particles break up the appearance of the web. The particles
can be
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CA 02143469 1999-12-21
distribr.ted in any selected pattern, for example in the form of letters,
words and/or
pictogr;~ms.
The floor covering embodying the invention can be manufactured by
substantially
the same manufacturing process as the one disclosed in German Application 44
OS 598.
However, the colours of the particles in the floor covering and of their
particle sections
must be: selected according to the requirements of the present disclosure.
Thus, the
contras~:ingly coloured cross linkable, elastomeric material granulate is
spread onto a
homogeneously coloured base web of the same material and of a first colour.
The base
web can be formed by feeding a homogeneously coloured cross linkable
elastomeric
material base granulate of a first colour from above into the gap between a
pair of counter
rotating, horizontally positioned parallel rollers. The granulate of
contrasting colour is
added and the resulting granulate mixture can be compressed in the gap without
generation
of pore;. and without mutual mixing of the colours of the granulate particles
along their
edges. 'The granulate of contrasting colour preferably is fed into the gap not
at the center
thereof but closer to one of the rollers. It is thereby avoided that this
granulate is exposed
to the substantial shear forces generated at the center of the gap. It is
assumed that this
permits the achievement of a precise patterned appearance of the floor
covering. The
granula~:e of contrasting colour includes particles which have at least two
particle sections
that are coloured differently from each other and from the base web. The
particles are
pressed into the base web flush with the surface of the web by a roller
calendar, a
continuous vulcanization machine, or a press and at a temperature of 160 to
190°C.
Subsequently, the particles are fixed in place by vulcanization of the
material of the
granulate and the base web. The mechanical stress on the particles and their
particle
sections is especially low in such a process. This allows one to achieve
colour patterns
that are free of blended or blurred colours on the visible surface of the
floor covering.
The finished, vulcanized product is not heat softenable and is characterized
by a high
chemical, mechanical and thermal stability.
~~11 known cross linkable vulcanizable elastomers suitable for use in floor
coverings can be used in the floor covering here described. For example,
rubbers and
elastom~:rs having the standard designations SBR, NBR and EPDM or natural
caoutchouc
as well as mixtures thereof can be used.
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A granulate having a colour which contrasts with the one of the base web can
be
obtained by independently making individual rubber mixtures of contrasting
colour,
forming each of the mixtures into a strand by way of extruders, and
subsequently
granulating them.
In a preferred embodiment, independently produced rubber mixtures of
contrasting
colour ;ire first shaped into a mufti-coloured strand by using a single
extruder, and then
granulated and spread onto the base web. However, the limitations with respect
to the
shape, colour and area of the equally coloured particle sections in accordance
with the
present disclosure must always be fulfilled. Mixing along the edges of the
individual
rubber mixtures of contrasting colour used for the manufacture of the mufti-
coloured
strand and granulate particles should be prevented during processing in the
extruder. This
can be ~ichieved by operating the extruder under especially gentle mixture
conditions. In
particular this means that temperatures in excess of 100°C should be
avoided as well as all
other stress which can lead to a complete disintegration of the rubber
mixtures employed.
In another preferred embodiment, the first particle section consists of a pair
of
essentially parallel subsections. Experience in the industrial field has shown
that dirt
particles settle in stripes on floors with vehicle or pedestrian traffic. Such
dirt deposits are
optically especially well concealed with the floor covering of this
embodiment. This
concealing effect is further increased when the first particle section is not
straight at least
at one ~ oint of its extent.
fn a further preferred embodiment, the smallest linear extent of the particles
at the
surface of the floor covering is l2mm. This means that the visible particle
sections are
relatively large, which especially in large rooms creates a less disquieting
surface effect
than do numerous small particles. These large particles moreover can be
arranged in the
form of pictograms.
'Smallest linear extent" refers to the shortest straight line which connects
the most
closely spaced opposite edges of a particle in the surface of the floor
covering.
fn still another preferred embodiment, the floor covering embodying the
invention
is electrically conductive with a leakage resistance below 106 ohms according
to DIN 51
953. In this embodiment, the base web accordingly includes embedded soot,
which results
in a dar:c black coloured base web. However, within the confines of the
present invention,
CA 02143469 1999-12-21
it is po;,sible to produce a floor covering wherein this black colour is not
dominant in the
visible surface thereof. Furthermore, there are no limits to the colour
variations possible.
In order to ensure that the surface of the floor covering is sufficiently
conductive, the
amount of base web surface covered by the granulate must be limited. The
surface
coverage can only be so dense that in any 20cm2 area of the floor covering the
base web is
still vis ible and, thus, accessible to electrodes.
Granulates for use in a floor covering embodying the present invention can be
made from natural or synthetic raw materials and are preferably produced with
mixing
arrangements conventionally used in the rubber industry, for example kneeders,
rolling
mills and/or extruders. In the final manufacturing step, the elastomer
mixtures used to
achieve granulate particles that have at least a pair of contrastingly
coloured particle
sections are transferred into a body of elongated shape from which short
portions are
subsequently sliced. The sliced-off portions together form the granulate. The
particle
sections of contrasting colours can be achieved by gently shaping two
elastomer strands of
contrasting colour into an elongated body by way of an extruder. It is however
preferable
to sufficiently reduce the friction forces in the extruder so that a mutual
mixing of the
individual colour components in the strand is avoided. Whether or not this has
been
achieved can be relatively easily monitored by way of the outer appearance of
the
elongated body. Whenever the outer surface of the body is free of pores and
has a clearly
structured colour pattern, free of blurred colours, a correspondingly exactly
structured
pattern is also present inside the elongated body. The body preferably has a
circular cross-
section, but can also have any other cross-sectional shape such as polygonal
or a shape that
includes both straight and curved portions.
~~hanges and modifications in the specifically described embodiments can be
carried ~~ut without departing from the scope of the invention which is
intended to be
limited only by the scope of the appended claims.
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