Method and tool for maintenance of hard surfaces, and a method for manufacturing such a tool

Abstract

A method is disclosed for maintaining a hard surface, the method comprising treating 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. The abrasive particles comprise diamond particles, and the treating is performed in the absence of an effective amount of crystallization agent on the contact surface. A tool for use in the method is also provided, as well as a floor surfacing machine comprising such a tool and a method for manufacturing such a tool.

Claims

1. A method of maintaining a gloss on an uncoated surface of a stone material, including marble, terrazzo, or polished concrete, at or above an initial value, the method comprising: providing a flexible pad of an open, lofty, three dimensional nonwoven web of fibers having diamond particles bonded thereto on a contact surface and dispersed within the flexible pad, the diamond particles having an average diameter of 3 to 6 m; treating the uncoated surface of the stone material by applying pressure and relative motion between the contact surface of the flexible pad and the uncoated surface of the stone material, in the absence of an effective amount of crystallization agent; and repeating the treating step as part of a regular daily maintenance routine to maintain the gloss at or above the initial value.

2. The method as claimed in claim 1, wherein the step of treating is performed substantially in the absence of liquid.

3. The method as claimed in claim 1, wherein the step of treating is performed in the presence of water.

4. The method as claimed in claim 3, wherein the step of treating is performed in the presence of water and a cleaning agent.

5. The method as claimed in claim 1, wherein the flexible pad has diamond particles bonded thereto by a secondary binder.

6. The method as claimed in claim 1, wherein the flexible pad has diamond particles bonded thereto only in a vicinity of the contact surface.

7. The method as claimed claim 1, wherein the flexible pad has diamond particles comprising at least one of natural diamond particles, industrial diamond particles and coated diamond particles.

8. The method as claimed in claim 1, wherein the flexible pad has a density of less than 40 kg/m.sup.3.

9. The method as claimed in claim 8, wherein the flexible pad has a density of 20-35 kg/m.sup.3.

10. The method as claimed in claim 1, wherein the stone material has a hardness of about 6-7 moh.

11. The method as claimed in claim 1, wherein said flexible pad, while in contact with the surface of stone material, is caused to rotate at a rotational speed of approximately 50-3000 rpm.

12. The method as claimed in claim 11, wherein said flexible pad, while in contact with the surface of stone material, is caused to rotate at a rotational speed of approximately 100-1500 rpm.

13. The method according to claim 1, wherein the treating is performed at least once daily.

14. The method according to claim 1, wherein the diamond particles are dispersed within the open, lofty, three dimensional nonwoven web of fibers to a predetermined depth from the contact surface of the flexible pad.

15. The method according to claim 1, wherein the stone material has a hardness of at least 5 moh.

16. The method according to claim 1, wherein the treating is performed by a scrubber/dryer combination floor surfacing machine.

17. The method according to claim 1, wherein the treating is performed by a ridable floor surfacing machine.

18. The method according to claim 1, wherein the treating is performed on a daily basis.

19. The method according to claim 1, wherein the stone material is concrete.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1a-1b show a pad according to a first embodiment.

(2) FIGS. 2a-2b show a pad according to a second embodiment.

(3) 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.

(4) FIGS. 4a-4b show a diagram of a pad according to the first embodiment, and an enlargement of a portion of the pad.

(5) FIG. 5 is a schematic sectional view of a floor surfacing machine on which a pad according to the invention is mounted.

DESCRIPTION OF EMBODIMENTS

(6) 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.

(7) 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.

(8) 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.

(9) 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.

(10) 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.

(11) 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.

(12) 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.

(13) 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.sup.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.

(14) 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-RD ethanol (available from Alfort & Cronholm AB, Bromma, Sweden) and 20 g of LANDS LS600F 4-8 m diamond particles (available from Lands Superabrasives, Co., New York, N.Y., USA). Just before application of the mixture, 60 g of 65% p-toluene sulfonic acid (PTS) was added as a hardener.

(15) 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.

(16) 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.

(17) 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 m silver coated diamond particles, and a second one, referred to as green, having 3-6 m 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, Minn., USA.

(18) The tests were made on two different surface types: Kolmrden marble (marble from the Kolmrden area outside Norrkping, Sweden) and K40 concrete. Each test was carried out on a surface of about 1 m.sup.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.sup.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.

(19) 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.

(20) When testing the 3M pads, each surface portion was first treated with the brown pad and subsequently with the gray pad.

(21) TABLE-US-00001 TABLE 1 Tests performed with water as lubricant on Kolmrden marble Pad Brown Gray Green Initial gloss 17 17 10 Liquid Water Water Water Final gloss 17 35 30

(22) TABLE-US-00002 TABLE 2 Tests performed without lubricant on Kolmrden marble Pad Brown Gray Green Initial gloss 20 25 28 Liquid No No No Final gloss 25 30 50

(23) 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 semi-gloss range.

(24) TABLE-US-00003 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

(25) TABLE-US-00004 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

(26) 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.

(27) TABLE-US-00005 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

(28) 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.

(29) 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.

(30) 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.

(31) 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.

(32) 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.

(33) 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.

(34) 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.

(35) 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.

(36) In a fourth embodiment, a three dimensionally woven or knitted pad may be used, whereby the binder/particle mixture is applied as described above.

(37) 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.

(38) 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.

(39) The invention is not limited to the use of phenol resin. Other examples of suitable resins are melamine, urea, epoxy and polyester resins.

(40) 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.

(41) 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.

(42) 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.

(43) 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.

(44) Alternatively, or additionally, the pad may be provided with a backing layer.

(45) A pad 1 for polishing a hard surface may be provided as described above. Such a pad may, in one embodiment comprise diamond particles having an average size of about 0.1-80 m. In preferred embodiments, the average particle size may be about 0.1-30 m, about 0.1-20 m or about 0.1-15 m.

(46) According to another embodiment, a grinding pad may be provided as described above, but comprising diamond particles of a different average particle size. For example, a grinding pad comprising diamond particles having an average size of about 80-800 m may be provided, preferably 80-600 m and more preferably 80-300 m.