U.S. patent application number 11/682504 was filed with the patent office on 2007-09-20 for flooring element.
Invention is credited to Malcolm Roger Curzon Donald.
Application Number | 20070218252 11/682504 |
Document ID | / |
Family ID | 36292967 |
Filed Date | 2007-09-20 |
United States Patent
Application |
20070218252 |
Kind Code |
A1 |
Donald; Malcolm Roger
Curzon |
September 20, 2007 |
Flooring element
Abstract
An apparatus for and a method of making a flooring element. The
flooring element is a tile formed of a polymer with embedded filler
material. The filler material includes abrasive particles adjacent
the top surface and a resilient or rubber-like material. The bottom
surface of the tile includes a plurality of particles embedded in
and extending from the bottom, which enables the tile to be
securely adhered to a substrate. One embodiment of a method of
making the tile includes adding a first layer containing a filler
material to a mold, vibrating the mold to cause the heavier filler
material to sink, applying a plurality of particles to the top of
the polymer mixture in the mold, and polymerizing the mixture in
the mold. In another embodiment, a second layer including resilient
particles is added to the mold above the first layer before the
mold is vibrated.
Inventors: |
Donald; Malcolm Roger Curzon;
(Dumfreisshire, GB) |
Correspondence
Address: |
KNOX PATENTS
P.O. BOX 30034
KNOXVILLE
TN
37930-0034
US
|
Family ID: |
36292967 |
Appl. No.: |
11/682504 |
Filed: |
March 6, 2007 |
Current U.S.
Class: |
428/143 ;
428/156 |
Current CPC
Class: |
B29C 39/42 20130101;
B29C 2791/008 20130101; E01C 11/24 20130101; E04F 15/02 20130101;
E01C 5/20 20130101; B29C 39/025 20130101; Y10T 428/24372 20150115;
B29C 70/64 20130101; B29C 39/006 20130101; Y10T 428/24479
20150115 |
Class at
Publication: |
428/143 ;
428/156 |
International
Class: |
E01F 9/04 20060101
E01F009/04 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 17, 2006 |
GB |
0605413.4 |
Claims
1. A flooring element comprising: a tile having a top surface and a
bottom surface, said bottom surface being substantially planar,
said tile formed as a single piece of a polymer having a first
concentration of a plurality of first particles and a second
concentration of said plurality of first particles, said plurality
of first particles including a plurality of abrasion resistant
particles, said first concentration greater than said second
concentration, said first concentration proximate said top surface
of said tile and said second concentration proximate said bottom
surface; and a plurality of second particles embedded in and
extending from said bottom surface of said tile.
2. The flooring element of claim 1 wherein said tile includes a
plurality of resilient material pieces embedded in said
polymer.
3. The flooring element of claim 1 wherein selected portions of
said top surface of said tile includes a photo-luminescent
material.
4. The flooring element of claim 1 wherein said top surface of said
tile includes a plurality of protrusions extending away from said
bottom surface, said plurality of protrusions selected from a group
including a plurality of blisters integral with said tile, a
plurality of pre-formed reflective items embedded in said polymer,
and a plurality of ridges integral with said tile.
5. The flooring element of claim 1 wherein said top surface of said
tile includes a component to stabilize said top surface against
ultra-violet light.
6. A flooring element comprising: a mixture of a polymerizable
resin, a hardener, and a filler material, said filler material
including abrasion resistant particles, said flooring element
having a thickness defining at least a first and a second region,
wherein said first region has a concentration of said abrasion
resistant particles that is greater than that of said second
region.
7. The flooring element of claim 6 further including an upper
surface and a lower surface, and wherein said first region is
provided at the upper surface.
8. The flooring element of claim 7 further including a third region
provided at said lower surface, wherein said third region has a
concentration of said abrasion resistant particles that is greater
than that of said second region.
9. The flooring element of claim 6 wherein said flooring element is
a tactile tile.
10. The flooring element of claim 6 wherein said filler material
comprises a first set of abrasion resistant particles and a second
set of abrasion resistant particles, the first set of abrasion
resistant particles having a density that is higher than that of
the second set.
11. The flooring element of claim 10 wherein said first set of
abrasion resistant particles includes one or both of sand and
bauxite.
12. The flooring element of claim 10 wherein said second set of
abrasion resistant particles includes a resilient material.
13. The flooring element of claim 6 wherein said mixture includes a
photo-luminescent additive.
14. The flooring element of claim 6 wherein said mixture includes a
component to stabilize said first region against the effects of
ultra violet light.
15. A method of making a flooring element including a mixture of a
polymerizable resin, a hardener and a filler material, the filler
material including abrasion resistant particles, the method
comprising the steps of: a) providing a first layer of a mixture in
a mold prior to polymerization of the mixture; b) treating said
mixture so that there is movement of the abrasion resistant
particles to define at least a first and a second region of said
mixture, wherein said first region has a concentration of abrasion
resistant particles which is greater than that of said second
region; and c) polymerizing said first layer.
16. The method of claim 15 wherein said step b) of treating said
mixture includes vibrating said mixture.
17. The method of claim 15 wherein the filler material includes a
first set of abrasion resistant particles having a density that is
higher than the density of at least the polymerizable resin such
that said first set of abrasion resistant particles moves to a
lower portion of a volume of said mixture during treatment of said
mixture to define said first region.
18. The method of claim 17 wherein said first set of abrasion
resistant particles includes one or both of sand and bauxite.
19. The method of claim 17 wherein the flooring element is formed
upside down in the mold such that said first region is adjacent an
upper surface of the flooring element, said upper surface
configured to be tread upon.
20. The method of claim 19 further including the step of adding a
third set of abrasion resistant particles to said mold during
polymerization to define a third region of said mixture, said third
region having a concentration of said abrasion resistant particles
that is greater than that of said second region.
21. The method of claim 17 wherein the filler material includes a
second set of abrasion resistant particles, said first set having a
density that is higher than that of said second set.
22. The method of claim 21 further including the step of providing
a second layer of said mixture in the mold prior to step c) of
polymerizing said mixture, said second layer including said second
set of abrasion resistant particles, said step c) of polymerizing
including polymerizing said second layer.
23. The method of claim 22 further including the step of vibrating
said mold to cause intermixing of the first and second layers.
24. The method of claim 21 wherein said second set of abrasion
resistant particles includes a resilient material.
25. The method of claim 15 further including the step of providing
at least one cavity at the mold to create at least one protrusion
of the flooring element.
26. The method of claim 15 further including the step of pressing
said mixture within said mold.
27. The method of claim 15 further including the step of adding a
photo-luminescent additive to said mixture.
28. The method of claim 15 wherein the viscosity of said mixture is
adjusted.
29. The method of claim 15 further including the step of adding to
said mixture a component to stabilize said first layer against the
effects of ultra violet light.
30. A method of making a flooring element, said method comprising
the steps of: a) adding a first layer to a mold, said first layer
including a resin, a hardener, and a plurality of first particles,
said mold having a shallow and substantially planar cavity
configured to receive said first layer, said mold having a bottom
that corresponds to a top of said flooring element, said plurality
of first particles including abrasion resistant material; b)
vibrating said mold until a substantial portion of said plurality
of first particles are located adjacent said bottom of said mold;
c) adding a plurality of second particles to a top surface of a
mixture in said mold, said mixture including said first layer, said
plurality of second particles being partially embedded in said top
surface and extending from said top surface; and d) polymerizing
said mixture in said mold.
31. The method of claim 30 further including, after said step d) of
polymerizing, a step e) of removing said mixture from said mold and
a step f) of storing said mixture on a flat horizontal surface for
a specified time.
32. The method of claim 30 wherein said first layer includes a
plurality of resilient particles.
33. The method of claim 30 further including a step al) of adding a
second layer to said mold after said step a), said second layer
including a resin, a hardener, and a plurality of resilient
particles, said mixture including said second layer.
34. The method of claim 30 further including a step of adjusting a
viscosity of said first layer before said step b) of vibrating.
35. The method of claim 30 further including, before said step a)
of adding said first layer, a step of adding a pre-formed
reflective item to said mold.
36. The method of claim 30 further including a step of adjusting a
viscosity of said first layer before said step b) of vibrating,
said viscosity adjusted by controlling one or both of a temperature
of said first layer and a ration of said resin to said
hardener.
37. The method of claim 30 wherein said mold includes a bottom
having a plurality of depressions configured to form a plurality of
features selected from a plurality of blisters and a plurality of
ridges.
38. The method of claim 30 wherein said first layer includes one or
both of a photo-luminescent material and a component to stabilize
said top surface against ultra-violet light.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of Application Number
0605413.4, filed Mar. 17, 2006, in the United Kingdom, hereby
incorporated by reference. STATEMENT REGARDING FEDERALLY SPONSORED
RESEARCH OR DEVELOPMENT
[0002] Not Applicable
BACKGROUND OF THE INVENTION
[0003] 1. Field of Invention
[0004] This invention pertains to floor tiling, in general, and to
tactile floor tiling, in particular. Tactile floorings have an
uneven surface so that they can provide information about the
surroundings to those walking on them, e.g., blind and
partially-sighted people.
[0005] 2. Description of the Related Art
[0006] There is an international standard for the designs and uses
of tactile tiling, for example, tiles with `blisters` arranged on a
square pattern are used on pavements at the edges of pedestrian
crossings, tiles with a triangular pattern are used near the edges
of railway platforms, and tiles with regularly spaced parallel
ridges are used at the tops and bottoms of stairs. In this context,
the `blisters` are about 25 mm in diameter, about 5 mm high, and
spaced 67 mm apart. Such tiling is highly beneficial to blind
people because the blisters can be detected by both a stick
sweeping the ground in front of them and through the soles of their
shoes. Tactile tiles may be provided in a contrasting color to that
of the rest of the flooring so that sighted caregivers for blind
persons and partially sighted people may be further warned of the
impending hazard.
[0007] Tactile tiling is used both outside, e.g., in the street and
public spaces, and inside, e.g., in public access areas, shopping
malls, and locations particularly frequented by blind people. For
outside use, the tiles are often cast from concrete or similar
materials, but for inside use, they are usually made from polymeric
materials, sometimes incorporating a degree of cushioning.
[0008] FIG. 1 shows a current design of polymeric tile and some
problems associated with it. Tile 1 consists of regularly spaced
blisters 2 on a substrate 3. The upper face has a hard-wearing
surface 4. Because of the shape and pattern of the blisters 2, tile
1 has to be cast upside down, i.e., with the blisters at the bottom
of the mold, and so, lower surface 5 is the top surface in the
mold. The mixture from which the tile is cast contains resin,
hardener, and a filler, such as sand or grit particles.
[0009] In the manufacturing process it is normal to fill the mold
and then vibrate it to release trapped air bubbles and settle the
mixture fully down into the mold. This vibrating process also
causes the filler particles to settle in the resin mixture and
leave a smooth surface at the top of the mold. Thus, after
polymerization and removal from the mold, this smooth surface
becomes lower surface 5 of tile 1. When the flooring is fitted, it
is normal to bond tiles 1 adhesively to a wood or concrete
foundation. A smooth surface 5 is not ideal for adhesive bonding.
It is possible to roughen surface 5, e.g., with sandpaper, but this
is not really practicable when working to deadlines. The result is
that, in use, tiles frequently become wholly, or partly, unbonded
and detached from the foundation.
[0010] Another problem that arises, occurs because the
polymerization process continues after the tiles have been removed
from the mold. If tiles 1 are not stored perfectly flat, e.g., they
are placed on a slightly uneven surface or, perhaps, overlapping
the edge of a pallet, it is possible that a `kink`, resulting in a
`permanent set`, may occur. This is illustrated as displacement 6
in FIG. 1. Though the tile 1 may be `bent straight` by the person
laying the floor and then adhesively bonded to the substrate, the
distortion 6 remains as an internal tensile stress. It is known
that adhesive bonds are weak in tension and, especially when the
adhesive is bonded to a smooth surface 5, failure of the bond is a
high probability. Adhesive failure, whether due to the smooth
surface 5, or exacerbated by a kink 6, is a common problem with the
fixing of this form of tile.
[0011] There is thus a need for a form of tiling with a hard
wearing surface and cushioned substrate, which can be bonded firmly
to the flooring foundation and remains firmly bonded for the
lifetime of the tile.
BRIEF SUMMARY OF THE INVENTION
[0012] According to various embodiments, apparatus for and methods
of making a flooring element are provided. The methods include
providing a mixture of a cross-linkable, polymerizable resin and a
hardener filled with abrasion resistant particles characterized in
that the abrasion-resistant particles are concentrated in the upper
layer of the flooring element to give a high friction, wear
resistant surface and further characterized in that a layer of
abrasion resistant particles is incorporated into the base surface
of the element prior to polymerization so that, after
polymerization, it forms a rough backing layer integral with the
flooring element, ideal for the adhesion of the element to the
foundation plane to which the flooring element is to be bonded with
an appropriate adhesive.
[0013] According to a first variation, the flooring element is cast
upside down in a mold.
[0014] According to a second variation, the mold is filled with the
polymerizable mixture, which is pressed into the mold.
[0015] According to a third variation, the mold is vibrated to
ensure complete filling and removal of air bubbles in the
polymerizable mixture.
[0016] According to a fourth variation, the vibration of the mold
causes segregation of the various fillers within the resin mixture
before polymerization occurs.
[0017] According to a fifth variation, the segregation process
produces a layer of abrasion resistant particles at or near the
base of the mold, which becomes the wearing surface of the flooring
element.
[0018] According to a sixth variation, resilient, such as rubber,
particles are included in the polymerizable mixture.
[0019] According to a seventh variation, the resilient particles
are concentrated in the upper layer of the mold, which becomes a
resilient substrate of the flooring element.
[0020] According to an eighth variation, the mold is provided with
parts such that, after casting, polymerization, and removal from
the mold, said parts creating areas of the flooring element which
project above the plane of the wearing surface.
[0021] According to a ninth variation, the projecting areas have
the form of partial spheres.
[0022] According to a tenth variation, the projecting areas have
the form of a ridge.
[0023] According to an eleventh variation, the projecting areas
have the form of parallel ridges with a groove between adjacent
ridges.
[0024] According to a twelfth variation, the parts of the mold are
pre-filled with a resin mixture containing a high concentration of
the abrasion resistant particles before the other resin-filled
mixture(s) is/are added to the mold.
[0025] According to a thirteenth variation, the pre-filling resin
mixture contains a photo-luminescent additive.
[0026] According to a fourteenth variation, pre-manufactured items
are located in the parts of the mold before the other resin-filled
mixture(s) is/are added to the mold so that, after polymerization,
the pre-manufactured items are bonded to the rest of the
polymerized matrix.
[0027] According to a fifteenth variation, the viscosity of the
polymerizable mixture is adjustable so that, during vibration prior
to polymerization, adequate segregation occurs due to density
differences with air bubbles rising and abrasion-resistant
particles sinking.
[0028] According to a sixteenth variation of the method, the
viscosity of the polymerizable mixture is adjusted by controlling
one or more of the temperature, proportion of resin to hardener,
and/or quantity of filler(s).
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0029] The above-mentioned features of the invention will become
more clearly understood from the following detailed description of
the invention read together with the drawings in which:
[0030] FIG. 1 is a side elevation of a prior art type of tactile
floor tile;
[0031] FIG. 2 is a part sectional elevation of a first embodiment
showing the polymerizable mixtures in a mold;
[0032] FIG. 3 is a part sectional elevation of the filled mold,
shown in FIG. 2, after vibration and addition of the rough backing
member;
[0033] FIG. 4 is a part sectional elevation of a second embodiment
showing the polymerizable mixture filling the mold;
[0034] FIG. 5 is a part sectional elevation of the mold, shown in
FIG. 4 after vibration and addition of the rough backing
member;
[0035] FIG. 6 is a part sectional elevation of a mold, the blister
of which has been pre-filled with a resin mixture containing a high
concentration of the abrasion resistant particles before the other
resin-filled mixture(s) is/are added to the mold and after the
settling and segregation caused by the vibrating of the mold and
its contents;
[0036] FIG. 7 is a part sectional elevation of the floor tile,
shown in FIG. 6, after polymerization;
[0037] FIG. 8 is a part sectional elevation of a mold, into which
an optical element has been placed before filling with the resin
mixture(s) and after vibrating the mold and its contents to settle
the resin mixture around the optical element and cause segregation
of the fillers within the mixture(s);
[0038] FIG. 9 is a part sectional elevation of the floor tile shown
in FIG. 8, after polymerization;
[0039] FIG. 10 is a part sectional elevation of a mold having parts
to form ridges in the floor tile and which parts have been
pre-filled with a resin mixture containing a high concentration of
the abrasion resistant particles before the other resin-filled
mixture(s) is/are added to the mold and after the settling and
segregation caused by the vibrating of the mold and its
contents;
[0040] FIG. 11 is a part sectional elevation of a floor tile, such
as one cast in the mold shown in FIG. 10 and showing one embodiment
of the incorporation of a photo-luminescent strip; and
[0041] FIG. 12 is a flow diagram of one embodiment of the
method.
DETAILED DESCRIPTION OF THE INVENTION
[0042] In the following description, the same reference number is
used for the same component or for different components fulfilling
an identical function.
[0043] Referring to FIGS. 2 and 3, the first embodiment provides
for the resin hardener mixture to be added to mold 10 in two
separate stages. In the first stage the resin and hardener are
mixed with a silica sand and bauxite filler to form a uniform
mixture and placed as a first layer 19 in mold 10. Mold 10 is
provided with concave projections 11 so that the mixture 19 therein
has convex blisters 2 after polymerization. As shown, first layer
19 is squeezed into the corners and blisters 11 and roughly leveled
to give a surface 16, only partly filling mold 10.
[0044] In the second stage, a further batch of the same resin and
hardener formulation is prepared, this time with a filler of
resilient, or rubber, particles 15. As before, a uniform mixture is
produced and added as a second layer 20 to mold 10 on top of
surface 16 of first layer 19 so that the mold is now full. As shown
in FIG. 2 the particles of sand and bauxite filler 14 and the
resilient particle filler 15 are uniformly distributed throughout
resin mixture 13 in their respective layers 19 and 20.
[0045] Mold 10 is now vibrated, primarily to settle the mixture in
the mold and blisters 11 and to allow trapped air bubbles (not
shown) to rise and leave the mold through surface 17. A secondary
effect of the vibration is to cause the denser sand and bauxite
particles to sink, thus collecting 14A near the bottom of mold 10,
11. This increases the wear resistance of the surface of the tile
after polymerization.
[0046] Another effect of the vibration is to meld the two layers of
polymer mixture together in the region of the boundary 16, which is
now shown dashed 16A to indicate this local mixing of the two
layers 19, 20. This process also causes some rubber particles 15 to
be incorporated into the first layer 19, as shown. After vibrating,
the resin surface 17 is leveled off with mold lip 12. As the same
resin and hardener is used for both layers, melding of the two
layers occurs naturally.
[0047] At this point in the process, the resin mixture has just
started to polymerize and surface 17 is tacky. With the surface in
this condition, a layer 18 of silica sand is placed on surface 17
so that the particles partly sink into tacky surface 17. If the
silica particles do not sink sufficiently into the surface of the
tacky resin, gentle pressure may be applied, e.g., with a roller, a
flat board or builder's float. The mold is now placed in an oven
and, in one embodiment, allowed to polymerize for three hours at
35.degree. C. After this the tiles are removed from the molds,
stacked horizontally on flat boards, and kept for 24 hours at
ambient temperature. This allows them to cool naturally and the
polymerization process to continue, essentially to completion. The
tiles are then trimmed to size to remove any edge imperfections and
packed into boxes for distribution. As previously, the boxes are
kept horizontal and flat though any further polymerizing set is
unlikely.
[0048] In one application of the first embodiment of the process,
the formulation is:
[0049] Resin Mixture
[0050] Resin, e.g., Nufins P U Casting Resin
[0051] Hardener, e.g., Nufins Casting Resin Hardener
[0052] The resin is mixed at the rate of between 2.5 to 4.0 parts
per 1.0 part of hardener, by weight.
[0053] First Layer
[0054] Silica sand filler, passing a 0.5 to 1.0 mm mesh screen, 90
wt. %
[0055] Bauxite filler, passing a 0.5 to 1.0 mm mesh screen, 10 wt.
%
[0056] The filler mixture is gradually added to the resin mixture
above until a rate of 65 to 72 wt. % is achieved, i.e., 35 to 28
wt. % resin. 1 to 2 wt. % pigment may be added in lieu of an
equivalent quantity of filler. Mixing under a vacuum is not
essential.
[0057] Second Layer
[0058] Equal parts of rubber particles, passing a 40 mesh screen
and a 26 mesh screen, are mixed together and added progressively to
the above resin mixture until a rate of 10 wt. % to 90 wt. % resin
is achieved. As the rubber particles do not pack well, there is a
much greater volume of rubber than resin and the rubber particles
float on the resin. Thus, mixing involves thoroughly wetting the
particles and kneading the whole to distribute the particles
evenly.
[0059] Vibration: 15 to 60 seconds, depending on the viscosity of
the resin/hardener mixture
[0060] Backing Layer
[0061] 0.2 to 0.7 mm silica sand particles are sprinkled on to the
tacky polymer surface to give a uniform covering. Normally, the
particles partly sink into the polymer matrix and bond with the
matrix. However, gentle pressure is applied, if required. Before
removal from the molds and, after polymerization, the tiles are
inverted and brushed gently to remove unbonded particles
[0062] Polymerization
[0063] 3 hours at 35.degree. C. in an oven, followed by removal
from the molds and 24 hours at room temperature, with each tile
horizontally on a flat board. The resin system taught is fully
cross-linked throughout the matrix but is also thermoplastic, which
assists the fitters when laying the tiles.
[0064] In the embodiment where the tiles are for outdoor
applications, an ultra-violet fight stabilizing agent is added,
along with the fillers, to the first layer only. (The agent is very
expensive and not required in the second layer.)
[0065] Referring to FIGS. 4 and 5, the second embodiment provides
for the resin hardener mixture to be added to mold 10 in a single
stage. The resin and hardener are mixed as before and the silica
sand, bauxite, and rubber filler added to form a single uniform
mixture. From a practical point of view, it is desirable to add the
less dense rubber particles first because they float and it is
easier to disperse the rubber particles into a free flowing liquid
than after the silica sand and bauxite mixture have been added.
[0066] As before, the mixture is pressed and squeezed into the
corners and blisters 11, filled 17 to the brim, and vibrated to
allow buoyant air bubbles (not shown) to rise to the surface and to
allow the mixture to fill the mold 10, 11 completely with surface
17 aligning with lip 12. During the vibration, as explained
previously, the silica sand (density 7.5-2.1) and bauxite (density
3.9) particles settle 14A to the lower part of mold 10, 11, through
the resin (density c. 0.9) to give a denser packing 14A at the base
of the mold, and especially in the blisters, to give greater wear
resistance to the tile after polymerization. Though more expensive,
the denser bauxite particles settle more quickly during the
vibration period and so enhance the wear resistance of the surface.
In this case, the rubber particles (density c. 0.9) remain
distributed uniformly throughout the single layer 21.
[0067] Close examination of the tile after polymerisation shows
that the sand and bauxite particles are often surrounded by a layer
of the smaller rubber particles, which provides an excellent bond
for the sand and bauxite, i.e., it promotes the wear resistance of
the tile surface 4.
[0068] As before, silica sand particles 18 are added to the tacky
surface 17 and become an integral part of layer 17. This is shown
in FIGS. 3 and 5 with the cross symbols representing these
particles passing through the surface 17 into the resin mixture 20
and 21 respectively.
[0069] In an application of the second embodiment of the process,
the formulation is:
[0070] Resin Mixture: As described above.
[0071] Fillers
[0072] Silica sand and bauxite filler mixture as above, 60 to 70
wt. %
[0073] Rubber particles, as described above, 3 to 10 wt %
[0074] The rubber and inorganic fillers are added progressively to
the resin mixture, as described above, until a rate of 62 to 75 wt.
% is achieved, i.e., 38 to 25 wt. % resin. 1 to 2 wt. % pigment may
be added in lieu of an equivalent quantity of filler. Again, mixing
under a vacuum is not essential, but the mixing process is
maintained for an adequate time to ensure homogeneity.
[0075] Vibration, Backing layer, and Polymerization: As described
above.
[0076] As shown in FIGS. 3 and 5, it is a feature of the method
that the vibration process leads to segregation 14A of the denser
inorganic fillers relative to the rest of the mixture 19, 20 and
21. The parameter affecting this segregation process is the
viscosity of the bulk mixture, after adding the fillers. Raising
the temperature of the resin and hardener reduces the viscosity, as
does adding less of the fillers. However, to maximize wear
resistance requires a large amount of the inorganic filler and that
the filler be located at, or close to, the surface of the tile,
(i.e., 4 in FIG. 1). Similarly, to maximize cushioning requires the
maximum quantity of rubber particles. Thus, there are conflicting
requirements and the formulation range given allows the skilled
person to select an appropriate balance for any particular
application.
[0077] Increasing the ratio of resin to hardener, i.e., reducing
the amount of hardener for a given quantity of resin, slows down
the rate of polymerization. As the polymerization increases the
viscosity, reducing the rate of polymerization allows the
segregating effect of the vibration to become relatively more
pronounced. This feature is implicit in the recommended resin
mixture rate of between 2.5 to 4.0 parts per 1.0 part of hardener,
by weight.
[0078] In one embodiment of the method, the resin, hardener, and
fillers are stored in a temperature-controlled room at 20.degree.
C., together with the mixer and vibrator. Thus, the whole
manufacturing process is conducted in a constant temperature
environment.
[0079] It is also noted that, in the single layer mixture 21, some
of the inorganic particles e g. those numbered 14 in FIG. 4 have a
greater distance to settle to reach zone 14A, than ones in the
lower part of mold 10. Thus, for the single layer application 21
(FIGS. 4 and 5), either a lower viscosity and/or a longer vibration
time is required. However, the polymerization process is continuing
all the time and vibration generates heat in the mixture, which
accelerates the polymerization. This emphasizes the importance of
the initial viscosity of the resin-hardener mixture. Typical
vibration times are 15-60 seconds for both the two layer system
(FIGS. 2 and 3) and the single layer system (FIGS. 4 and 5).
[0080] Having explained the method and its application to the
manufacture of flooring tiles, specific developments of the
principle will now be taught.
[0081] The principle of two layered manufacture has been explained
(FIGS. 2 and 3) and, in other embodiments, the number of layers is
increased to three layers. In such a case, a resin/hardener mixture
is prepared as usual but loaded with a higher than normal
concentration of sand/bauxite filler and the resulting mixture 22
placed in the blisters 11 (FIG. 6) or ridge-forming channels LLA
(FIG. 10). An injection means, such as a mastic gun (not shown), is
used to place the required quantity of mix 22 in place. After
filling molds 10 or LOA with one or two additional layers, as
taught above, the effects of the vibration melds the adjacent
layers together at their boundary layers. After polymerization,
highly wear-resistant blisters 22A (FIG. 7) or ridges 28 (FIG. 11)
are created.
[0082] Another embodiment is to incorporate illumination into the
tiling. This is done by placing pre-formed glass "cats' eyes" 24
(FIG. 8) into blisters before adding resin 21A. In this embodiment,
a blob of adhesive 27, e.g., a blob of grease or a weak adhesive
(such as used on memo-attachment notes) is used to hold the cat's
eye 24 in place so that the resin mixture 21A can fill gap 25
during the vibration and thus hold the cat's eye 24 firmly after
polymerization (FIG. 9). As shown 26A, 26B, incident light is
refracted into cat's eye 24, reflected from rear surface 24A and
re-emitted 26A, 26B. As shown, the lip 25 grips cat's eye 24, as
well as via the adhesion of the resin mix 21A to the surface 24A.
In various embodiments, the cats' eyes 24 are pure glass elements
or cast from a glass particle/resin mixture. The glass may be plain
or colored, as desired. The effect is enhanced if the tiles are
illuminated by low-level, glancing lighting.
[0083] A still another embodiment is to incorporate a
photo-luminescence substance into a concentrated filler 22, as
shown by numeral 23 (FIGS. 8 and 10). Such a substance absorbs
incident light and emits it after dark or if the lights failed,
e.g., during a fire emergency. In FIG. 10, a photo-luminescent
mixture is used for one ridge 23 located between two highly
wear-resistant ridges 22 to give added protection. In FIG. 11,
either a pre-formed photo-luminescent strip 23A is incorporated
into ridge 22, e.g., using the same method as for cats' eye 24, or
a separate photo-luminescent liquid-resin mixture is injected into
the appropriate channel 1A, before resin mixtures 22, 21A are
added.
[0084] Flooring elements made according to the method are an
improvement over present tactile floor tile technology by
optimizing the resin system and the actual location of the wear
resistant and cushioning components within the tile itself. The
skilled person will appreciate the variations of the method of the
teaching, all of which are implicit in the disclosure.
[0085] FIG. 12 illustrates a flow diagram of various embodiments of
the method of making a flooring element tile 1. In the first
embodiment, the first step 102 is to prepare a mixture of resin and
hardener, followed by the step 104 of adding the filler, which is
an abrasion resistant material. This combination is then added to
the mold 106 as a first layer. Along a parallel path, a step 118 of
preparing a mixture of resin and hardener, followed by the step 104
of adding the filler, which is a resilient material, such as rubber
or a rubber-like material. This combination is then added to the
mold 122 as a second layer, after the first layer has been added to
the mold 106. After the mold is filled, the next step 108 is to
vibrate the mold, followed by the steps 110, 112 of leveling the
top and adding particles to the top surface. The next step 114 is
to polymerize the tile in the mold. After polymerization, the next
step 116 is to remove the tile from the mold and temporarily store
the tile flat while the tile completes curing.
[0086] In a second embodiment, mixture is prepared 102, and the
filler is added 104, with the filler including both abrasion
resistant material and resilient material. The mold is then filled
106 with only a single layer and steps 118, 120, 122 for a second
layer are not performed.
[0087] In a third embodiment, before the first layer is added 106
to the mold, the step 124 of adding an item to the mold is
performed. The item includes pre-formed reflective items, cats'
eyes 24, and/or pre-formed photo-luminescent strip 23A. In other
embodiments, a third layer is added to the mold.
[0088] According to a first embodiment of the method, the flooring
element is cast into a mold in two layers, the first layer
comprising a mixture of a cross-linkable, polymerizable resin and a
hardener filled with abrasion resistant particles and placed in the
mold 106 first to form a wear-resistant surface layer and a second
layer comprising a mixture of a cross-linkable, polymerizable resin
and a hardener filled with rubber particles and placed in the mold
122 on top of the first layer to form a resilient substrate and a
layer of abrasion resistant particles is incorporated into the base
surface of the element, prior to polymerization so that, after
polymerization 114, it forms a rough backing layer integral with
the flooring element, ideal for the adhesion of the element to the
foundation plane to which the flooring element is to be bonded with
an appropriate adhesive.
[0089] According to first variation of the first embodiment of the
method, the mixture forming the first layer of the flooring element
includes a component to stabilize the polymerized element against
the effects of ultra violet light.
[0090] According to second variation of the first embodiment of the
method, the vibration of the mold causes intermixing of the first
and second resin, hardener and filler layers, so that the two
layers polymerize together to form effectively a single layer with
different concentrations of fillers in different parts of said
single layer.
[0091] According to a second embodiment of the method, the flooring
element is cast from a single mixture of a cross-linkable,
polymerizable resin and a hardener filled with both
abrasion-resistant particles and rubber particles, placed in a mold
and the mold and its contents vibrated for a period of time
sufficient to allow air bubbles to rise out of the mixture and for
the denser abrasion-resistant particles to sink towards the bottom
of the mold to form a wear resistant surface layer to the element
with most of the rubber particles remaining in the bulk of the
mixture to form a resilient substrate and a layer of abrasion
resistant particles is incorporated into the base surface of the
element, prior to polymerization, so that, after polymerization, it
forms a rough backing layer integral with the flooring element,
ideal for the adhesion of the element to the foundation plane to
which the flooring element is to be bonded with an appropriate
adhesive.
[0092] In one such embodiment of the method to produce a floor
tile, a resin and hardener mixture is prepared and
abrasion-resistant and rubber particle fillers are progressively
added to the mixture, with thorough mixing between each addition.
When the full quantity of fillers has been added, a mold is filled
with the mixture, which is gently pressed into place. The mold,
with its mixture, is then vibrated for a period of time during
which any air bubbles rise to the surface and the denser fraction
of the fillers sinks towards the bottom of the mold. This
segregation of the denser, abrasion-resistant fillers to the bottom
of the mixture in the mold, which becomes the hard-wearing surface
of the flooring element, is a feature.
[0093] After the mold has been vibrated for the required period of
time, the upper surface of the mixture is leveled off with the top
of the mold and silica sand particles are sprinkled onto the tacky
surface of the mixture, where the particles partly sink into the
resin mixture. Gentle pressure may be applied to the silica
particles, if they do not sink sufficiently into the resin
mixture.
[0094] After polymerization in an oven, when the silica sand
particles on the surface of the mixture become firmly bonded to the
polymer matrix, the tile is removed from the mold and placed on a
flat, level surface for a further period of time, at ambient
temperature, to allow the polymerization to proceed to completion.
The tiles, thus prepared, are then ready to be supplied for use.
Particular advantages of the tile are that it is flexible and so
may be fitted on slightly uneven surfaces. The rough surface of the
silica particle backing is ideal for adhesive bonding to the floor
foundation and the concentration of abrasion-resistant particles
gives a hard-wearing surface,
[0095] If the tiles are to be used outside, stabilization against
UV light is desirable, as the stabilizing agent is very expensive,
it is desirable to concentrate it in the surface layer of the tile.
This is done by preparing the resin mixture in two parts. In the
first part, only the abrasion-resistant particles and NV agent are
used as fillers and this mixture is placed in the mold first and
pressed down to give a first layer. In the second part, only rubber
particle filler is used and this mixture added to the mold as a
second layer. The effect of the vibration is both to cause the
abrasion-resistant particle to sink, as before, but also to cause
mixing between the two layers and give an essentially uniform
matrix for polymerization.
[0096] In one embodiment of a mold, partial spherical depressions
are provided in the base so that flooring tiles made from the mold
have raised `blisters`, which blind and partially sighted people
can detect, either with a stick or through the soles of their feet.
In another embodiment of a mold, parallel channels are provided in
the base so that the tiles have raised parallel ridges, separated
by grooves.
[0097] In one application of the molds of these designs, a
resin/hardener mixture with a high concentration of abrasion
resistant particles is used to fill the depressions before the
normal resin mixture(s) is/are added. The vibration causes a degree
of mixing at the interface between any two adjacent mixture layers
so that there are no plane(s) of weakness between the adjacent
layers. An advantage of this is that the raised parts, which are
most prone to wear, are also the most wear-resistant. If a
photo-luminescent additive is incorporated into the mix for the
raised parts, it absorbs light and re-emits it, e.g., after dusk or
during a fire alert.
[0098] In a further embodiment, pre-formed reflective items are
placed in all or some of the depressions to catch and reflect
incident light, as "cats' eyes" do on roads. This further
emphasizes the presence of the tiling (and the hazard to which it
refers). The effect is enhanced if the tile is illuminated by low
level, glancing light.
[0099] From the foregoing description, it will be recognized by
those skilled in the art that an apparatus for tactile flooring
elements and a method of making tactile flooring elements such as
tiles has been provided. The tiles 1 have an upper surface that
includes abrasion resistant material and the bottom of the tiles 1
include a surface that is rough and suitable for adhesively
attaching to a substrate. The tiles 1 also include, in one
embodiment, a resilient filler disposed between the upper and
bottom surfaces of the tile 1 so as to provide a cushioning effect
for the tile 1.
[0100] The method includes providing a mixture of a cross-linkable,
polymerizable resin and a hardener filled with abrasion resistant
particles characterized in that the abrasion-resistant particles
are concentrated in the upper layer of the flooring element to give
a high friction, wear resistant surface and further characterized
in that a layer of abrasion resistant particles is incorporated
into the base surface of the element, prior to polymerization so
that, after polymerization, it forms a rough backing layer integral
with the flooring element, ideal for the adhesion of the element to
the foundation plane to which the flooring element is to be bonded
with an appropriate adhesive.
[0101] In one embodiment, rubber particles are also included in the
resin-filler mixture to provide cushioning in the substrate of the
tile. The resin-filler mixture is applied to the mold either in a
single layer or in multiple layers.
[0102] A feature of the method is that the viscosity of the resin
mixture is carefully controlled so that, during the period of
vibration to settle the mixture fully into the mold, segregation of
the filler(s) occurs within the resin mixture. The denser abrasion
resistant particles sink through the resin mixture towards the base
of the mold, which is the wearing surface of the tile, after
polymerization and removal from the mold. The mold may be provided
with parts to create areas of the tile, which project above the
plane of the surface of the tile. Means to increase the wear
resistance of the projecting areas and to incorporate means of
illuminating parts of the tiles are taught.
[0103] While the present invention has been illustrated by
description of several embodiments and while the illustrative
embodiments have been described in considerable detail, it is not
the intention of the applicant to restrict or in any way limit the
scope of the appended claims to such detail. Additional advantages
and modifications will readily appear to those skilled in the art.
The invention in its broader aspects is therefore not limited to
the specific details, representative apparatus and methods, and
illustrative examples shown and described. Accordingly, departures
may be made from such details without departing from the spirit or
scope of applicant's general inventive concept.
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