Technical field
[0001] The invention relates to a method and a tool for maintenance of hard surfaces, primarily
concrete (cement), terrazzo and granite floor surfaces, but also marble or limestone
surfaces. The invention particularly relates to a method and a tool for maintenance
which is suitable for use on a daily basis to maintain a polished hard floor surface.
Background
[0002] It is known in connection with cleaning or light polishing of floor surfaces to use
a pad in the form of a three-dimensional non-woven web. The pad is usually provided
as a circular, disc-shaped body, which is to be disconnectably mounted on a circular
carrier plate, which in use is caused to rotate in a plane parallel with the floor
surface, such that the pad, when brought into contact with the floor surface, is slightly
compressed by the pressure arising between the floor surface and the carrier plate.
The carrier plate is usually driven by a motor and may be mounted on a carrier frame,
which may be arranged to be pushed or pulled by a walking operator or which may be
arranged as a ridable vehicle.
[0003] Such pads are formed from fibers of an organic material, e.g. polyamide and/or polyester,
particularly polyethylene terephtalate. In some cases the fibers also include natural
fibers, such as walnut fibers or coconut fibers.
[0004] The fibers of the pad is interconnected at their mutual points of contact by so-called
melt bonding, whereby the fibers are subjected to heat that cause the outer part of
the fibers to slightly melt and thereby to bond to each other.
[0005] Alternatively, or additionally, the fibers may be interconnected at their mutual
points of contact by the pad being impregnated with a polymer resin, hereinafter referred
to as a "primary binder".
[0007] US-A-3,537,121 discloses pads for polishing surfaces of aluminum, plastic, wax and similar surfaces.
US-A-3,537,121 also discloses production of such pads. In
US-A-3,537,121 a binder mixed with abrasive particles is applied to the pad by passing the pad between
a pair of squeeze rolls, one of which is partially immersed in a container for a mixture
of binder resin and abrasive particles, after which the pad is allowed to cure or
dry. Thus, in
US-A-3,537,121 a pad is provided, which is entirely impregnated by the binder and abrasive particles.
[0008] US-A-4,893,439 discloses a pad for polishing floor surfaces or aluminum. The pad consists of fibers
of organic material and constitutes a lofty open non-woven structure, and contains
a binder binding abrasive particles to the fibers. The pad shown in
US-A-4,893,493 has larger voids than that shown in
US-A-3,537,121, and thereby has an improved ability to absorb dirt, so that it can be used for a
longer period. Also the pad disclosed in
US-A-4,893,493 is entirely impregnated by binder and abrasive particles.
[0009] EP-A-0 397 374 discloses a pad for floor polishing machines, which also is entirely impregnated
by binder and abrasive particles.
[0010] Pads of the above type are frequently used for so-called "burnishing", i.e. dry polishing
(often on a daily basis) of very lightly worn surfaces at high speed (1500-3000 rpm)
and relatively low pressure, with a view to restoring a polished surface. This type
of treatment is commonly used for both vinyl and marble floorings. Pads suitable for
this purpose are available from 3M® under the designation "3M
™ Floor Pads", and provide no or little effect on very hard floor surfaces, such as
terrazzo or concrete, which have been subject to wear for a longer period of time.
[0011] EP-B-0 562 919 discloses a non-woven pad of polymer fiber, which is entirely impregnated by a binder
comprising a mixture of curable plastic resin and abrasive particles having a particle
size of 0,1-30 µm. As examples of curable resins are mentioned phenol resin, acrylic
resins, melamine resin and urea resin. Diamond is mentioned as one among several other
examples of plausible abrasive particles. However, according to
EP-B-0 562 919, the pad disclosed therein is suitable for treatment of marble floor surfaces, and
only in combination with crystallization chemicals, which means that treatment must
be made in the presence of liquid containing a salt-forming acid.
[0012] The pad in
EP-B-0 562 919 is also provided by passing a non-woven pad through a nip between two squeeze rolls,
one of which being partially immersed in a binder/abrasive particles mixture, such
that the binder and abrasive particles, via the surface of the cylinder is distributed
in the pad.
[0013] Since the pad disclosed in
EP-B-0 562 919 is to be used in the presence of crystallization chemicals, the method described
in
EP-B-0 562 919 actually constitutes a vitrification method, used with a view to improving the stain
resistance and durability of a marble floor. This method is not suitable for daily
maintenance purposes, since it involves use of special crystallization chemicals,
including acids, which are to react with calcium present in the floor surface to form
insoluble calcium salts. Such a method is typically used once in connection with the
initial preparation of the polished marble floor, and thereafter at intervals of 6-12
months. The method described in
EP-B-0 562 919 is thus too complicated for being used on a daily basis.
[0014] Pads of the type referred to in
EP-B-0 562 919 are sold by 3M® under the designations "3M
™ 5200 Brown Stone Renew Pad" and "3M
™ 4000 Grey Stone Polish Pad", and are used for treating marble in the presence of
crystallization chemicals and at relatively low speeds (below 250 rpm) .
[0015] The need for crystallization chemicals makes the polishing work more complicated,
since the chemicals are to be applied to the surface, possibly followed by removal
of excess chemicals, which also contribute to making the polishing work more time
consuming. Handling and application of the chemicals also constitute a potential hazard
to the environment in general and to the work environment in particular.
[0016] It is also known to provide a polished stone or concrete surface by using tools comprising
grinding or polishing elements made from a plastic resin mixed with abrasive particles,
i.a. diamond particles. Since such elements are fixedly mounted on a usually rotating
plate, they do not have the ability to compensate for unevenness in the floor, which
may lead to uneven treatment of the floor surface, or to scratching or staining of
the floor surface in case such an element is to contact the surface at an excess pressure.
Yet another problem is that debris, such as grains of sand, small stones or metal
may get stuck in or near the elements and cause scratching of the floor surface. Finally,
this type of tools require special machinery capable of applying a higher pressure
to the contact surface between the tool and the floor surface.
[0017] WO03/075734 discloses a disc-shaped device for cleaning purposes, comprising a nylon scouring
material, which is arranged on a rigid disc, whereby grinding elements containing
industrial diamonds are placed in recesses in the active scouring surface. A disadvantage
with the device disclosed in
WO03/0753 is that it does not eliminate the risk of debris getting stuck in or near the grinding
elements. Yet another disadvantage is that this tool is complex and therefore more
prone to breaking and more difficult and expensive to manufacture.
[0018] Hence, there is a need for an improved and simplified method and tool for daily maintenance
of hard surfaces. Preferably, the method should be simple to use, e.g. by persons
who do not have specialist training in floor surface preparation, and the method should
be usable with conventional floor surfacing equipment, e.g. burnishing machines, etc.
Also, the tools should be easy to manufacture, not too expensive and durable.
Summary of the invention
[0019] It is an object of the invention to provide improved technique, which wholly or partially
eliminate the problems with the prior art methods and pads. In particular, it is an
object to provide a method of treating a hard surface which is more easy to use and
which provides a comparable or better result than the prior art methods.
[0020] The invention is based on the idea that abrasive particles in the form of diamond
particles provide a polishing effect which is vastly superior to that achievable with
those abrasive particles used in the examples shown in e.g.
EP-B-0 562 919, and that this polishing effect is so superior as to eliminate the need for crystallization
chemicals.
[0021] The invention is defined by the appended independent claims. Embodiments are set
forth in the dependent claims and in the following description and drawings.
[0022] Thus, there is provided a method for maintaining a hard surface, the method comprising
treatment of the surface with a flexible pad, in the presence of abrasive particles
on a contact surface between the pad and the hard surface. The abrasive particles
comprise diamond particles bonded to the pad, and the treating is performed in the
absence of an effective amount of crystallization agent on the contact surface.
[0023] The term "diamond" is understood to include natural diamond as well as synthetic
diamond, and diamond particles being coated with any suitable coating, e.g. silver.
[0024] The term "effective amount" is understood as an amount that is sufficient to achieve
a measurable gloss improvement as compared to the same treatment using a liquid containing
no crystallization agent at all. Amounts known to be effective are about 1-2 liters
of crystallization agent (comprising 2-30 % by weight of e.g. magnesium hexafluorosilicate)
per 50 m
2 of floor surface for a single treatment operation. Hence, amounts known to be effective
on an ad-hoc basis range from about 0,4 g of magnesium hexafluorosilicate per m
2 floor surface. However, diluted crystallization agent, e.g. at a ratio of 1:100 is
also known to be effective when used repeatedly, e.g. in connection with daily or
weekly maintenance. Hence, amounts known to be effective for maintenance on a regular
basis range from about 0,004 g of magnesium hexafluorosilicate per m
2 floor surface. It is understood that there are other types of crystallization agents,
e.g. zinc hexafluorosilicate, hydrofluoric acid and oxalic acid. The values given
above may thus need to be adjusted to apply to the respective type of crystallization
agent chosen.
[0025] The combination of a flexible pad and diamond particles provides compensation for
unevenness in the surface, and distributes the pressure applied to the pad evenly.
Also, this combination, through the flexibility of the pad, considerably reduces the
risk of the diamonds scratching the surface.
[0026] Using diamond particles as abrasive particles when polishing hard stone surfaces
provides an effect equal to or better than use of conventional abrasive particles,
both in wet and dry conditions. In particular, the use of diamonds enables the crystallization
agent to be abolished, thereby eliminating its handling.
[0027] The treatment may be performed substantially in the absence of liquid on the contact
surface, i.e. during substantially dry conditions; or in the presence of water on
the contact surface, i.e. during wet conditions. In particular, the treatment may
be performed in the presence of water and a cleaning agent on the contact surface,
thereby making it combine excellently with the daily maintenance/cleaning operations.
[0028] In one embodiment, the abrasive particles are bonded to the pad by means of a secondary
binder. Hence, no abrasives need to be added when treating the floor. Specifically,
the abrasive particles may be bonded to the pad only in the vicinity of the contact
surface. This is advantageous, since the abrasive particles present in the parts of
the pad that are not in contact with the hard surface do not fulfill any function
and therefore can be seen as a waste.
[0029] The abrasive particles may have an average diameter of 0,1 to 30 µm, preferably between
0,1 and 15 µm and most preferably between 10 and 15 µm.
[0030] The abrasive particles may comprise at least one of natural diamond particles, industrial
diamond particles and coated diamond particles.
[0031] In one embodiment, the pad that is used comprises an open, lofty, three dimensional
non-woven web of fibers. Such webs are available at a relatively low cost and in standard
sized adapted for the existing surfacing machines.
[0032] The pad may have a density of less than 40 kg/m
3, preferably 20-35 kg/m
3. Thus, the pad comprises a relatively large amount of voids, into which dust, debris
and particles may migrate during the treatment. Thus, dust is to a large extent contained
in the pad rather than being distributed in the area where the treatment is taking
place, eliminating the need for additional dust collecting equipment. Also, by allowing
debris to migrate into the pad, the risk for scratching of the surface is reduced.
[0033] The method is particularly suitable for use on a floor surface.
[0034] The method is particularly applicable where the surface is a stone or stone-like
material having a hardness of about 5 moh or more, preferably 6-7 moh. Examples of
such surfaces are concrete, terrazzo, granite etc.
[0035] The pad, while in contact with the hard surface, may be caused to rotate at a rotational
speed of 50-3000 rpm, preferably of 100-1500 rpm.
[0036] Furthermore, there is provided a tool for treating a hard surface, the tool comprising
a flexible pad having an active treatment surface presenting abrasive particles bonded
to the pad. The pad presents a first portion wherein said abrasive particles are present
in a first concentration, and a second portion having a second, lower concentration
of said abrasive particles, said abrasive particles comprising diamond particles.
[0037] In one embodiment, the second portion is substantially free from diamond particles.
[0038] Since the abrasive particles present in the parts of the pad that are not in contact
with the hard surface do not fulfill any function, pads according to the invention
can be manufactured at a lower cost.
[0039] The flexibility of the pad eliminates or reduces the harmful effects that diamond
abrasive particles could otherwise have on the hard surface. Hence, the tool may be
used for any hard surface, such as surfaces of wood, laminate, marble, granite, concrete,
terrazzo, etc. However, the tool is particularly effective for hard stone or stone-like
surfaces, such as granite, concrete, terrazzo, etc.
[0040] In one embodiment, the pad consists of a disc-shaped body having a thickness and
a first surface, wherein said abrasive particles are present on said first surface
and down to a depth from said first surface, which depth is less than said thickness,
such that said first portion is at said first surface and said second portion is at
a second surface, opposite said first surface. By leaving the second surface free
from abrasive material and binder, the attachment of the pad to a Velcro hook connector
on a carrier plate is facilitated.
[0041] In a second embodiment, the pad consists of a disc-shaped body having a thickness
and a first surface, wherein said abrasive particles are present over less than the
entire first surface, such that said first and second portions are situated adjacent
each other at said first surface. This second embodiment facilitates migration of
dust and debris into the pad.
[0042] In one embodiment, the pad comprises an open, lofty, three dimensional non-woven
web, including a plurality of fibers, which are adhered to each other at their points
of mutual contact.
[0043] The abrasive particles may be bonded to the fibers of the pad by a secondary binder.
Hence, the bonding of the fibers of the pad does not in any way need to be negatively
affected by the fact that the abrasive particles are only present at the contact surface.
[0044] As non-limiting examples, the secondary binder may be selected from a group consisting
of phenol resin, melamine resin, urea resin and epoxy resin.
[0045] In one embodiment, the secondary binder forms a plurality of distinct droplets having
a maximum diameter which is smaller than an average length between two points of mutual
contact of a fiber. Thus, the fibers are not entirely coated by the binder resin,
facilitating further the migration of dust and debris into the pad.
[0046] The pad may further comprise second abrasive particles selected from a group consisting
of graphite, tin oxide, silicon carbide and aluminum oxide.
[0047] The pad is preferably provided in the shape of a circular disc having a diameter
between 30 and 100 cm and an uncompressed thickness between 1 and 5 cm.
[0048] Finally, there is provided a method for manufacturing a pad for treating a hard surface.
The method comprises: providing a pad, and applying, on a first surface of the pad,
a mixture of a binder and abrasive particles including diamond, such that said pad
presents a first portion wherein said abrasive particles are present in a first concentration
and a second portion, having a second, lower concentration of said abrasive particles.
In one embodiment, the second portion is substantially free from said abrasive particles.
The abrasive particles may be provided to the first surface by spraying, rolling or
dipping.
Brief description of the drawings
[0049] Figs 1a-1b show a pad according to a first embodiment.
[0050] Figs 2a-2b show a pad according to a second embodiment.
[0051] Figs 3a-3b show enlarged photographs of a pad according to the present invention,
before and after the binder and abrasive particles have been applied.
[0052] Fig. 4a-4b show a diagram of a pad according to the first embodiment, and an enlargement
of a portion of the pad.
[0053] Fig. 5 is a sectional view of a floor surfacing machine on which a pad according
to the invention is mounted.
Description of embodiments
[0054] The description will first focus on a tool suitable for use in the method for maintenance
of hard surfaces, subsequently on the method for manufacturing the tool, and finally
on the use of the tool for maintenance of a hard surface.
[0055] Referring to Fig. 1a, there is shown a pad 1 made up from an open, lofty three dimensional
non-woven web of fibers 2. A first surface of the pad 1 has a portion P1 presenting
abrasive particles bonded to the web by means of a secondary binder, i.e. a binder
having as a main purpose to bond fibers to the web. The pad 1 is circular in shape.
[0056] Referring to Fig. 1b, a cross section along the line S1-S2 in Fig. 1a is shown. As
is indicated in Fig. 1b, the portion P1 presenting the abrasive particles is present
at the first surface A and to a depth D, which is less than the thickness T of the
pad 1. Hence, at the second surface B there is a portion P2, which is substantially
free from the abrasive particles and the secondary binder.
[0057] When referring to "portions", it is to be understood as a portions of the macrostructure
of the pad 1 and not portions of the individual fibers.
[0058] Referring to Figs 2a and 2b, there is shown a similar pad 1, the difference being
that there is a portion P2' also at the first surface A, which portion P2' is substantially
free from the abrasive particles and the secondary binder.
[0059] In both embodiments, the abrasive particles are present throughout the secondary
binder, and the fibers are bonded to each other by a primary binder and/or by being
melt-bonded.
[0060] A description of the preparation of a pad 1 according to the embodiment discussed
with reference to Figs 1a and 1b will now be given.
[0061] As a starting material, circular, disc shaped Glit/Microtron® Tan Floor Polishing
Pad having a diameter of 20 inches (51 cm), a thickness of 28 mm and a weight of 157
grams was used. Such pads are available from Glit/Microtron, Wrens, GA, USA. The starting
density of the pad was thereby 27 kg/m
3. Fig. 3a is a microscope photograph showing the pad prior to application of the polymer
resin/abrasive particles. From Fig. 3a, it can be seen that the fibers constituting
the pad are held together at their points 10 of mutual contact by a primary polymer
resin. The pad is flexible and resilient and comprises polyester and nylon fibers.
[0062] A homogenous polymer resin mixture was prepared, consisting of 200 g PA resin 52-68
phenol resin (available from Perstorp AB, Perstorp, Sweden), 100 g of T-RÖD® ethanol
(available from Alfort & Cronholm AB, Bromma, Sweden) and 20 g of LANDS LS600F 4-8
µm diamond particles (available from Lands Superabrasives, Co., New York, NY, USA).
Just before application of the mixture, 60 g of 65% p-toluene sulfonic acid (PTS)
(available from [insert vendor]) was added as a hardener.
[0063] The resin mixture was sprayed onto a first one A of the surfaces of the polishing
pad, using a standard-type compressed air spray gun (normally used for spraying paint).
The pad with the uncured resin thereafter weighed 173 grams. Subsequently, the pad
was placed in a hot air oven at approximately 120°C for approximately 20 minutes.
[0064] The pad has now assumed the appearance that can be seen from Fig. 3b, which is a
microscope photograph. Globules or droplets 11 of the resin/particle mixture are formed
along each fiber, also between the fibers' points of mutual contact. The droplets
are so distributed that the fibers to which they are adhered are not entirely covered.
A more clear illustration of this is found in Figs 4a-4b, which show a pad as described
above with reference to Figs 1a-1b, and an enlargement of a portion of that pad (Fig.
4b), wherein droplets 11 of binder/particle mixture are attached to the fibers.
[0065] In order to evaluate the performance of the pad produced as described above, comparative
tests were carried out in order to evaluate two different 20 inch (51 cm) pads, prepared
as described above: a first one, referred to as "yellow", having 7-12 µm silver coated
diamond particles, and a second one, referred to as "green", having 3-6 µm normal
diamond particles. As a reference, two different commercially available pads were
used: a 20 inch (51 cm) 3M™ 5200 Brown Stone Renew Pad and a 20 inch (51 cm) 3M™ 4000
Grey Stone Polish Pad were used, both available from 3M, St. Paul, MN, USA.
[0066] The tests were made on two different surface types: Kolmården marble (marble from
the Kolmården area outside Norrköping, Sweden) and K40 concrete. Each test was carried
out on a surface of about 1 m
2, using a Coor & Kleever Crystallizer 1250KG floor surfacing machine (available from
Coor & Kleever, S.A., Barcelona, Spain) having a single carrier plate adapted for
receiving a 20 inch floor pad and rotating at about 175 rpm. The test included polishing
the surface for about 1 minute/m
2. The surface gloss was measured at several spots on the area before and after each
treatment using a Sanwal/Cenma IG-310 Glosschecker. The gloss value in the tables
below constitute the average value for each area. High gloss is rated 80-90°. Semi
gloss is rated 50-75°. Satin is rated 30-45°. Rubbed effect is rated 20-25°. Flat
sheen is rated 5-15°.
[0067] Each surface was tested both dry and using water as a lubricant. Additionally, the
concrete surface was tested using Coor Rosa/K-2 crystallizer (available from Coor
& Kleever S.A., Barcelona, Spain) as lubricant, i.e. the crystallization chemical
mentioned in
EP-B-0 562 919 as comprising magnesium hexafluourosilicate as crystallization agent.
[0068] When testing the 3M™ pads, each surface portion was first treated with the brown
pad and subsequently with the gray pad.
Table 1: Tests performed with water as lubricant on Kolmården marble
Pad |
Brown |
Gray |
Green |
Initial gloss |
17 |
17 |
10 |
Liquid |
Water |
Water |
Water |
Final gloss |
17 |
35 |
30 |
Table 2: Tests performed without lubricant on Kolmården marble
Pad |
Brown |
Gray |
Green |
Initial gloss |
20 |
25 |
28 |
Liquid |
No |
No |
No |
Final gloss |
25 |
30 |
50 |
[0069] From tables 1 and 2, it can be concluded that on marble, which is a relatively soft
stone having a hardness of about 3-5 moh, and using water as a lubricant, the 3M™
pad combination (brown and gray) provide a slightly better effect, although both the
gray and the green pads achieved values falling within the "satin" range. However,
during dry conditions, the green pad achieved a remarkable improvement, reaching the
semigloss range.
Table 3: Tests performed with water as lubricant on K40 concrete
Pad |
Brown |
Gray |
Yellow |
Green |
Initial gloss |
30 |
29 |
24 |
35 |
Liquid |
Water |
Water |
Water |
Water |
Final gloss |
29 |
29 |
35 |
46 |
Table 4: Tests performed without lubricant on K40 concrete
Pad |
Brown |
Gray |
Yellow |
Green |
Initial gloss |
29 |
34 |
30 |
48 |
Liquid |
No |
No |
No |
No |
Final gloss |
34 |
35 |
48 |
58 |
[0070] From Tables 3 and 4, it is noted that in wet conditions and on K40 concrete, having
a hardness of about 6-7 moh, the combination of brown and gray pads did not provide
any measurable improvement at all, whereas the combination of yellow and green pads
provided a distinct improvement. In dry conditions, a small improvement was noted
for the surface treated with the combination of brown and gray pads, whereas a major
improvement was noted for the surface treated by the combination of yellow and green
pads.
Table 5: Tests performed with Coor Rosa/K-2 crystallizer as lubricant on K40 concrete
Pad |
Gray |
Green |
Initial gloss |
41 |
35 |
Liquid |
VMC-Pink |
VMC-Pink |
Final gloss |
45 |
51 |
[0071] From table 5, it is noted that some effect is achievable with a gray pad using Coor
Rosa/K-2 crystallizer as lubricant on K40 concrete, and that a somewhat better effect
is achievable with the green pad using Coor Rosa/K-2 crystallizer as lubricant.
[0072] All in all, it is concluded that the pad according to the invention provides a noticeable
improvement as compared with the prior art. The improvement is particularly noticeable
during dry conditions and on concrete.
[0073] Fig. 5 is a sectional view of a floor surfacing machine 20 on which a pad 1 according
to the invention is mounted so as to define a contact surface 9 with the hard surface
8, which in this example is a floor surface. The pad 1 is mounted on a driven, rotatable
carrier plate 4, which is typically journalled in bearings and thus rotatable relative
to a machine body 5, on which a motor unit 6 is arranged. In this embodiment, the
machine has a handle 7, and is thus adapted for being held/pushed/pulled by a walking
operator. It is recognized that in other embodiments the floor surfacing machine 20
may be e.g. a ridable vehicle fitted with a carrier plate 4 that is adapted for receiving
the pad 1.
[0074] The pad 1 and method described above can be used for everyday cleaning/maintenance
of polished hard surfaces, such as stone, concrete or terrazzo floor surfaces using
a floor surfacing machine such as a scrubber/dryer combination machine, e.g. the Nilfisk
CR1300; a single disc floor maintenance machines (low speed or high speed), e.g. the
Nilfisk 510B or 545; a burnisher, e.g. the Nilfisk SDH5120, BHS5120 or BHS7014, all
of which are available from Nilfisk-Advance, Stockholm, Sweden.
[0075] The treatment of the floor surface is typically performed by causing the pad, when
in contact with the floor surface, to rotate in a plane parallel with the floor surface.
Typical rotational speeds are from 50 rpm to 3000 rpm. However, lower or higher rotational
speeds are not excluded.
[0076] As is clear from the above, a first embodiment of the pad according to the invention
comprises an open, lofty, three dimensional non-woven web, including a plurality of
fibers, which are adhered to each other at their points of mutual contact by means
of a primary binder, and in which abrasive particles are mixed with a secondary binder
and applied only to a first surface of the pad, such that the pad is only partially
impregnated by the binder/particle mixture. Alternatively, or additionally, the fibers
may be melt-bonded to each other.
[0077] In a second embodiment of the pad, binder/particle mixture is only applied to parts
of said first surface. This can be achieved by masking those parts of the surface
to which the binder/particle mixture should not be applied.
[0078] In a third embodiment, the pad is entirely impregnated with the binder/particle mixture,
e.g. by using such squeeze rollers as are described in
EP-B-0 562 919. In a variant of this embodiment, a relatively thin impregnated woven or non-woven
pad is attached to a thicker carrier pad in order to provide the flexibility. According
to variants of this embodiment, a substantially two-dimensional woven or non-woven
web is attached to a thicker carrier pad.
[0079] In a fourth embodiment, a three dimensionally woven or knitted pad may be used, whereby
the binder/particle mixture is applied as described above.
[0080] In a fifth embodiment, the abrasive particles are present in the material of the
pad. In a first alternative, the pad is a non-woven fiber pad substantially as described
above, with the diamond particles included in the fiber material. In a second alternative,
the pad is a polymer foam pad with the diamond particles included in the foamed polymer
material.
[0081] In a sixth embodiment, the pad is a polymer foam pad, to a surface of which a binder/particle
mixture is applied as described above.
[0082] The invention is not limited to the use of phenol resin. Other examples of suitable
resins are melamine, urea, epoxy and polyester resins.
[0083] Furthermore, the hardener may be selected from any hardener suitable for the type
of resin selected. Also it is possible not to include the hardener, e.g. by allowing
the pad to cure at a higher temperature and/or for a longer period of time.
[0084] Also, the solvent (ethanol was used in the example) is provided merely to reduce
the viscosity of the mixture and thereby to facilitate spraying thereof. Any suitable
solvent may be used, and the solvent may also be excluded, provided that the method
of application so allows.
[0085] The abrasive particles preferably include diamond. However, floor treatment pads
may be produced according to the principles set forth above using other types of abrasive
particles, or combinations thereof, as well, e.g. those mentioned in
EP-B-0 562 919. In particular silver coated diamond particles have proven to provide good results
as well. Naturally, the diamond particles may be combined with other types of abrasive
particles.
[0086] It is understood that the pad 1 having secondary binder and abrasive particles as
described above may be attached to a disc or plate having an arbitrary connector for
being connected to a carrier plate of the surfacing machine, or that the pad may be
directly connectable to the surfacing machine by means of a Velcro-type hook arrangement
provided on the carrier plate, the hooks of which engage the fibers of the pad 1.
Hence, the maintenance tool may be composed of the pad with the primary binder, the
secondary binder and the abrasive particles, possibly with the addition of dyes or
printed areas providing information on the type of pad, manufacturer, trademark etc.
[0087] Alternatively, or additionally, the pad may be provided with a backing layer.
1. A tool for treating a hard surface, the tool comprising a flexible pad (1) having
an active treatment surface presenting abrasive particles bonded to the pad, wherein
the pad presents a first portion (P1) wherein said abrasive particles are present
in a first concentration, and a second portion (P2, P2') having a second, lower concentration
of said abrasive particles, said abrasive particles comprising diamond particles.
2. The tool as claimed in claim 1, wherein said second portion (P2) is substantially
free from diamond particles.
3. The tool as claimed in claim 1 or 2, wherein the pad comprises a disc-shaped body
having a thickness (T) and a first surface (A), wherein said abrasive particles are
present on said first surface (A) and down to a depth (D) from said first surface,
which depth is less than said thickness (T), such that said first portion (P1) is
at said first surface and said second portion (P2) is at a second surface (B), opposite
said first surface.
4. The tool as claimed in any one of the preceding claims, wherein the pad comprises
a disc-shaped body having a thickness (T) and a first surface (A), wherein said abrasive
particles are present over less than the entire first surface (A), such that said
first and second portions (P1, P2') are situated adjacent each other at said first
surface (A).
5. The tool as claimed in any one of the preceding claims, wherein the pad comprises
an open, lofty, three dimensional non-woven web, including a plurality of fibers (2),
which are adhered to each other at their points (10) of mutual contact.
6. The tool as claimed in claim 5, wherein the abrasive particles are bonded to the material
of the pad by a secondary binder.
7. The tool as claimed in claim 6, wherein the secondary binder comprises at least one
of phenol resin, melamine resin, urea resin and epoxy resin.
8. The tool as claimed in claim 6 or 7, wherein said secondary binder forms a plurality
of distinct droplets (11) having a maximum diameter which is smaller than an average
length between two points of mutual contact of a fiber.
9. The tool as claimed in claim 6-8, wherein the abrasive particles are present throughout
the secondary binder.
10. The tool as claimed in any one of claims 5-9, wherein the fibers are bonded to each
other by a primary binder and/or by being melt-bonded.
11. The tool as claimed in any one of the preceding claims, further comprising a second
abrasive particles selected from a group consisting of graphite, tin oxide, silicon
carbide and aluminum oxide.
12. The tool as claimed in any one of the preceding claims, wherein the pad has the shape
of a circular disc having a diameter between 30 and 100 cm and an uncompressed thickness
between 1 and 5 cm.
13. A floor surfacing machine (20), comprising a tool (1) according to any one of the
preceding claims 16-27.
14. A method for manufacturing a tool for treating a hard surface, the method comprising:
providing a pad (1), and
applying, on a first surface (A) of the pad, a mixture of a binder and abrasive particles
including diamond, such that said pad presents a first portion (P1) wherein said abrasive
particles are present in a first concentration and a second portion (P2), having a
second, lower concentration of said abrasive particles.
15. The method as claimed in claim 14, wherein said second portion (P2) is substantially
free from said abrasive particles.
16. The method of claim 14 or 15, wherein said binder and abrasive particles are applied
to said first surface (A) by spraying, rolling or dipping.
17. A method for maintaining a hard surface, the method comprising treatment of the surface
with a flexible pad (1), in the presence of abrasive particles, bonded to the pad,
on a contact surface between the pad (1) and the hard surface, wherein:
the abrasive particles comprise diamond particles, and
the treatment is performed in the absence of an effective amount of crystallization
agent on the contact surface.
18. The method as claimed in claim 17, wherein the treatment is performed substantially
in the absence of liquid on the contact surface.
19. The method as claimed in claim 17, wherein the treatment is performed in the presence
of water on the contact surface.
20. The method as claimed in claim 19, wherein the treatment is performed in the presence
of water and a cleaning agent on the contact surface.
21. The method as claimed in claim 20, wherein the treatment is performed using a pad
(1) having abrasive particles bonded to it by means of a secondary binder.
22. The method as claimed in any one of the preceding claims, wherein the treatment is
performed using a pad (1) having abrasive particles bonded to it only in the vicinity
of the contact surface.
23. The method as claimed in any one of claims 17-22, wherein the treatment is performed
using a pad (1) having abrasive particles of an average diameter of 0,1 to 30 µm,
preferably between 0,1 and 15 µm and most preferably between 10 and 15 µm.
24. The method as claimed in any one of claims 17-23, wherein the treatment is performed
using a pad (1) having abrasive particles comprising at least one of natural diamond
particles, industrial diamond particles and coated diamond particles.
25. The method as claimed in any one of claims 17-24, wherein the treatment is performed
using a pad (1) comprising an open, lofty, three dimensional non-woven web of fibers.
26. The method as claimed in claim 25, wherein the wherein the treatment is performed
using a pad (1) having a density of less than 40 kg/m3, preferably 20-35 kg/m3.
27. The method as claimed in any one of claims 17-26, wherein the hard surface is a floor
surface.
28. The method as claimed in any one of claims 17-27, wherein the hard surface is a stone
or stone-like material having a hardness of about 5 moh or more, preferably 6-7 moh.
29. The method as claimed in claim 28, wherein the hard surface is a concrete or terrazzo
surface.
30. The method as claimed in any one of claims 17-29, wherein the pad (1), while in contact
with the hard surface, is caused to move in relation to the hard surface.
31. The method as claimed in claim 30, wherein the pad, while in contact with the hard
surface, is caused to rotate at a rotational speed of 50-3000 rpm, preferably of 100-1500
rpm.