ABRASIVE ARTICLE AND METHOD FOR THE PRODUCTION THEREOF

Abstract: An adhesive article which has an adhesion of a metal sediment to a carrier material which is stronger than that adhesion which is obtained in the abrasive articles disclosed according to the prior art, which abrasive article comprises a multiplicity of metal sediments which are located some distance apart and are bound to a carrier material, abrasives being embedded in said metal sediments or adhering to the top surfaces of said metal sediments, said metal sediments being obtained via a known electroplating technique, wherein a layer of binder is applied to one side of the carrier material such that said layer of binder extends continuously in cavities which have been formed in the metal sediment from the side where the carrier material is located, and wherein the binder can be a plastic.

Description: Abrasive article and method for the production thereof Description The invention relates to abrasive articles comprising a multiplicity of metal sediments which are located some distance apart and are bound to a carrier material such that at least one part of each metal sediment is exposed on an outer surface of the carrier material, abrasives being embedded in said metal sediments or adhering to the top surfaces of said metal sediments, said metal sediments being obtained via a known electroplating technique, such as, for example, electrodeposition, currentless sedimentation or vacuum deposition. An abrasive article of this type is disclosed in British Patent GB 1 534 448. This patent describes an abrasive article and a method for the production thereof, the abrasive article comprising an electrically conducting layer with non-metallic abrasives arranged on the surface thereof, a mask, which lies over the conducting layer and leaves exposed parts of the layer located some distance apart, an abundance of abrasive being arranged on said exposed parts and metal sediments being arranged on the electrically conducting layer at the location of said exposed parts to hold the abrasive in position, the abrasive and the metal sediments being applied essentially simultaneously via an essentially static electrodeposition, currentless sedimentation or vacuum deposition process. At the location of the metal sediments, the said electrically conducting layer is, as a consequence of the metal deposition, completely embedded in said metal sediments. Said layer thus forms the carrier material for the metal sediments and joins the metal sediments placed some distance apart to one another in order to form an abrasive article. An abrasive article must have a strength suitable for its use and a high flexibility. The strength of the abrasive article is determined by the adhesion of the metal sediments to the carrier material and the strength of the carrier material itself. The adhesion of the metal sediments to the carrier material is highest in the locations where the carrier material is fully embedded in a metal sediment. The adhesion of the metal sediments to the carrier material is lowest at the edges of the metal sediment where a metal sediment with embedded carrier material is located on one side and carrier material alone is located on the other side. The strength of the carrier material itself is lower than the strength of a metal sediment with embedded carrier material. If the abrasive article is loaded too heavily, this will give way at the location of the non- embedded carrier material, probably along the edges of one or more metal sediments. The aim of the invention is to provide an abrasive article which has an adhesion of a metal sediment to a carrier material which is stronger than that adhesion which is achieved in the abrasive articles disclosed according to the prior art. This aim is achieved in that a layer of binder is applied to one side of the carrier material such that said layer of binder extends continuously into cavities which have been formed in the metal sediment from the side where the carrier material is located. The cavities into which the layer of binder extends after application of the latter are produced by making use, during electrodeposition, of a cathode which has sections placed some distance apart on its surface, between which sections an electrically non-conducting material, for example a resin, has been applied. In the course of the electrodeposition procedure, metal is first deposited on the exposed surface of the protruding sections of the cathode. Moreover, metal is deposited along the exposed surface of the fibres of the carrier material as soon as at least a small part of one of the fibres is in contact with the surface of a protruding section of the cathode, because the carrier material is formed of electrically conducting, porous material, with the result that the carrier material is also able to act as a cathode. More and more metal is then deposited on previously deposited metal, so that the deposition of metal extends in all directions perpendicular to the exposed surface of the cathode - including the parts of the fibres acting as cathode - and of the metal formed. Ultimately, the deposits grow into one another some distance perpendicularly above the cathode on the side where the carrier material is located. When all of the deposits have grown together and a further common layer of a certain thickness has then grown on top of the original, individual deposits, the so-called metal sediments have been formed. During this procedure, as a consequence of the growth pattern of the original, individual deposits, cavities have then formed in the section of the metal sediment which is located between the covered surface of the cathode and the locations where the original, individual deposits have grown together. The growth pattern of the deposits can be controlled as a function of the shape of the exposed, protruding sections of the cathode, the thickness of the fibres of the carrier material used and the mutual spacing of said fibres. Depending on the growth pattern, various shapes of cavities, for example undercut cavities, can form. Preferably, the surface area of an exposed, protruding section of the cathode is smaller by at least a factor of 2 than the surface area of the part of the carrier material exposed by the mask. Otherwise it would not be possible for more than 1 growth surface to be present per metal sediment to be formed, as a result of which the intended growing together of the original, individual deposits would not be able to take place and it would then not be possible for cavities to be formed. The carrier material can be composed of an electrically conducting or non-conducting, porous material. If an electrically non-conducting material is used, the growth pattern of the deposits of metal will differ from that according to the case discussed above in which the carrier material is made up of an electrically conducting material, with the result that said carrier material also acts as a cathode. After all desired metal sediments have been formed, including the intended cavities, electrodeposition is terminated and the cathode is removed. A layer of binder is then applied to that side of the carrier material where the cathode was located, or in other words the side on which the metal sediment has not formed. Preferably, said binder is composed of a plastic and the latter is applied in liquid form to the desired side of the carrier material. During said application of the binder, care is taken that the binder fills the cavities as completely as possible. The binder then sets, as a result of which a strong and flexible layer is obtained which extends over the entire surface of the carrier material on the side where the metal sediments are not located. The abrasive article can now be subjected to a heavier load than is possible with the abrasive articles disclosed in the prior art. The added layer of binder increases the strength of the abrasive article especially in those locations where the known abrasive articles have only carrier material, whilst the layer of binder is firmly anchored to the metal sediments through the cavities filled with binder. The invention will be illustrated in more detail below with reference to the appended drawings in which an illustrative embodiment is shown in detail. Figure 1 shows a view of an abrasive article according to the invention obliquely from below; for the sake of clarity, the layer of binder is not shown. Figure 2 shows a cross-sectional view of an abrasive article at the location of a metal sediment in the case where the metal sediment has just been fully formed. Figure 3 shows a cross-sectional view according to Figure 2 of the finished abrasive article. In Figure 1, the finished abrasive article is indicated in its entirety by reference numeral 1. The abrasive article 1 comprises a carrier material 2, metal sediments 3 and a layer of binder 11. The layer of binder 11 is not shown in Figure 1 but is located in the manner shown in Figure 3 on that side of the carrier material 2 where the metal sediments 3 shown are not located. At the location where a metal sediment has been formed, each metal sediment 3 is bound to the carrier material 2 via points of adhesion 4 and growths 5 onto the fibres of the carrier material. Any metal which is amenable to electrodeposition, currentless sedimentation or vacuum deposition can be chosen as the metal for the metal sediment 3. By way of example, nickel can be chosen. The carrier material 2 can be a gauze material, fabric, sieve material, non-woven material, *mesh', 'woven' or a 'non- woven' material. In Figure 1, the carrier material is shown, merely by way of example, as a gauze material which is characterised by a regular pattern of fibres and openings between the fibres. The carrier material 2 can be electrically conducting or electrically non-conducting, porous material. In Figures 1 to 3, the carrier material is shown, merely by way of example, as an electrically conducting material. The carrier material 2 can be made of any organic or inorganic material. Figure 2 shows the situation at the end of the deposition process. An electrodeposition process has been assumed here, merely by way of example. The installation for the production of the metal sediment 3 in a known manner comprises a cathode 6, a mask 9 and a liquid from which the metal is deposited on that side of the cathode 6 where the mask 9 is located. Neither this liquid nor the other parts of the installation are shown in Figures 1 to 3 because an installation of this type is fully known and (at least as far as the missing components are concerned) has nothing to do with the present invention. The cathode 6 has a few protruding sections 7. The space between the various protruding sections 7 is filled with a filler 8. In the case where electrodeposition is employed, said filler is an electrically non-conducting material, for example a resin or a plastic. The carrier material 2 is laid on the cathode 6 and the mask 9 is laid on the carrier material 2. In the case where electrodeposition is employed, the mask 9 is made of an electrically non-conducting material. The mask 9 shields part of the surface of the carrier material 2 from the electroplating bath. At the point in time when an electric current is applied between cathode and anode, the metal is able to deposit only on the surfaces of the carrier material 2 which are not shielded by the mask 9. The deposition of metal starts on the exposed surfaces 12 of the protruding sections 7 of the cathode 6. At the end of the electrodeposition process, said initial deposits will be visible as points of adhesion 4 (Figure 1). The metal deposit then grows on the metal deposited previously. As can be seen from Figure 2, the metal then grows further in the horizontal direction, that is to say in a direction parallel to the surfaces 12 of the protruding sections 7 of the cathode 6, and in the vertical direction, that is to say perpendicular to the surfaces 12 in the direction of the carrier material 2. Metal also deposits on the fibres of the carrier material 2 as soon as a part thereof comes into contact with a surface 12 or with a metal deposit which has formed on a surface 12. Said metal deposits on the fibres of the carrier material 2 are indicated in Figures 2 and 3 by the reference numeral 5. The result of carrying out the electrodeposition process is a collection of metal sediments 3 in which carrier material 2 is partly embedded, which are joined, at the location of a metal sediment, to the carrier material by the points of adhesion 4 and the growths 5, during the production of which cavities 10 have formed. At the end of the electrodeposition process, the cathode 6, the filler 8 and mask 9 are removed and a layer of binder 11 is applied to that side of the carrier material 2 where the metal sediments 3 have not formed. During this operation, the binder 11 flows into the cavities 10. In Figures 2 and 3, the cavities 10 are shown by way of example as undercut cavities. The layer of binder 11 then extends over the complete surface of the carrier material 2 on one side thereof. The strength of the abrasive article 1 is increased by the additional strength which the layer 11 provides, as well as the stronger adhesion of the metal sediments 3 to the carrier material 2 as a whole.

Claims: Claims 1. Abrasive article (1 ) comprising a multiplicity of metal sediments (3) which are located some distance apart and are bound to a carrier material (2) such that at least one part of each metal sediment is exposed on an outer surface of the carrier material, abrasives being embedded in said metal sediments or adhering to the top surfaces of said metal sediments, said metal sediments being obtained via a known electroplating technique, such as, for example, electrodeposition, currentless sedimentation or vacuum deposition, characterised in that a layer of binder (11) is applied to one side of the carrier material (2) such that said layer of binder extends continuously in cavities (10) which have been formed in the metal sediment (3) from the side where the carrier material is located. 2. Abrasive article according to Claim 1, wherein the binder (11) is a plastic. 3. Abrasive article according to one of the preceding claims, wherein the cavities (10) are undercut cavities. 4. Abrasive article according to one of the preceding claims, wherein the carrier material (2) is electrically non¬ conducting. 5 brasive article according to one of Claims 1-3, wherein the carrier material (2) is electrically conducting. 6. Abrasive article according to one of the preceding claims, wherein the surface (12) of an exposed section (7) of a cat ode (6) used in the electrodeposition process is smaller by at least a factor of 2 than the surface of the part of the carrier material (2) exposed by the mask (9). 7. Method for the production of an abrasive article according to one of the preceding claims, wherein metal sediments (3) are applied in a known manner to a carrier material (2) and a cathode (6) required in said method is removed from the abrasive article formed, characterised in that a layer of binder (11) is applied to at least one side of the carrier material (2) in such a way that the binder (11) at least partially fills at least one cavity (10). 8. Method according to Claim 7, wherein the binder (11) is applied in liquid form. 9. Method according to Claim 7, wherein the binder (11) is applied in paste form. 10. Method according to one of Claims 7-9, wherein the binder (11) solidifies or is hardened after application.

Inventors: FERRONATO SANDRO GIOVANNI GUIS, FERRONATO, SANDRO, GIOVANNI, GUISEPPE
Applicants: FERRONATO SANDRO GIOVANNI GUIS, FERRONATO, SANDRO, GIOVANNI, GUISEPPE
Application year: 1995
Main classification: B24D3
IPC codes: B24D3, B24D18