MXPA97003387A

MXPA97003387A - Abrasi products

Info

Publication number: MXPA97003387A
Application number: MXPA/A/1997/003387A
Authority: MX
Inventors: J Kardys Gary; G Kelly Robert
Original assignee: Norton Company
Priority date: 1994-11-09
Filing date: 1995-08-09
Publication date: 1997-08-01

Abstract

Coated abrasive materials can be made of a backing material and abrasive elements comprising abrasive particles adhered to a rigid base material, said elements being rigidly adhered to the backing material in a predetermined pattern

Description

PRODUCTS flBRRSIVQS FIELD OF THE INVENTION This invention relates to coated abrasive products which can be made very simply and reproducibly by an easily automated production process.

BACKGROUND OF THE INVENTION In a conventional process for the manufacture of coated abrasives, a support is prepared and then treated with a coating of a forming ream which is then L5 partially cures before depositing a layer of abrasive particles on it. The former coating is then cured and an additional binder coating, known as a reverse primer, is applied over the grain to roots. The abrasive grain is applied either by gravity coating or by an electrostatic process in which the grains are propelled to the surface to be coated by electrostatic forces. This is known as the technique of UP coating. In these processes, the product is obtained: on sale in the shape of a cylinder that is then cut to form discs or strips, some of which can be molded on ribbons. Clearly, said method involves the parallel formation of a significant amount of waste material. Particularly when the cost of the grain is a significant element in the total cost of the product, this is a waste that is convenient to avoid. The official use of grain has been proposed for example in U-Pi-1 509 240, which describes an abrasive having a plurality of abrasive elements each comprising a plurality of abrasive particles, wherein the elements are adhered to a material of support in a predetermined configuration. In recent years a new grain form has been developed. This grain has a filtering particle shape with a substantially uniform transverse shape and a length dimension perpendicular to that transverse section which is at least as long as the largest dimension of the cross section. One form of such grains is made from an alumina sol-gel which has been shaped into the filamentous particle form before being dried and baked to produce a remarkably effective abrasive grain. Said grains are described in USP 5,009,676 and coated abrasives made using such particles are described in USP 5,103,590. It has now been found that coated abrasives *, comprising abrasive particles and particularly filamentous abrasive particles, can be obtained in a highly flexible and efficient manner that allows l < .-t "elaboration according to particular specifications" of a coated abrasive for a specific application. The use of the technique results in minimal waste of grain and the maximum effectiveness established as a target of the grain that is used. The use of the present invention also avoids the danger that the filamentous particles deposited on a substrate may be forced to assume a position different from the orientation lessened before the binder has hardened to the extent that the orientation is fixed.

DESCRIPTION OF FL INVENTION The present invention provides a coated abrasive having a plurality of abrasive elements each comprising a base pad and a plurality of abrasive particles each bonded by an ex-patch thereof to a surface of the pad, said elements being adhered to a support material in a predetermined configuration. The base pad can have any suitable shape but in general a circular disk is more satisfactory. However, square, diamond, oval or even irregular discs can be thought of as embodiments of this part of the element.

The abrasive particles may be of any type, including fused and sol-gel aluminas, to the zirconium, silicon carbide, garnet and the like. The particles can have any desired shape such as forms' • >; similar predetermined or random forms. However, they are often similar in size in order to fit in the same classification of grit. Due to the manner in which they are used, it is often preferred that the particles have a dimension significantly larger than the others. It is said that such particles have a "weak form". The forms must have been produced either by the forming process or by grinding larger masses of the abrasive. A particularly advantageous form of abrasive particle for the practice of this invention is the filament abrasive particle 5. üLight particles, when used in the present invention, are preferably substantially of the same length so that the far ends of the surface of the base pad are at the same distance from the surface. However, in some circumstances, differential lengths may have certain advantages. The preferred material from which the abrasive particles can be made is an alumina sol-gel. The methods of making said alumina sol-gel are described in USP 4,314,827; 4,623,364; 4,770,671; 4,768,167; 4,848,041; 5, 4,881,951; 5,076,815; 5,139,978; 5,185,299; 5,203,884; 5,204,300; 5,219,806; 5,236,471; and others.

The material from which the base pad is made can be the same one from which the abrasive particles are formed. Thus, in the case of products having alumina sol-gel filamentous abrasive particles, the base pad and the filaments can be formed simultaneously in a single operation, which could be, for example, a molding or casting operation. . Alternatively, the filaments could be placed with one end of each located on a non-solidified alumina sol-gel disk which can then be dried and baked with the particles on position to form an alumina base pad with which the filamentous abrasive particles are chemically identical and in which the particles are rooted. Alternatively, the pad may be made of a material that is more conventionally used as a binder in the construction of coated abrasives. This could therefore be a phenolic resin, an epoxy resin, a radiation-curable polyurethane (including modified poly-urethanes), anneale, formaldehyde resins, urea-formaldehyde resins and the like. The pad can be conveniently chosen to be compatible with the binder, to which it is to be applied in the production of a coated abrasive, using the elements of the invention. Another alternative is to make the base pad of a fibrous material which is then impregnated with a curable ream formulation. Then, the fibers help to retain the vertical openting of the filamentous particles while curing the re ina. In addition to the alternatives discussed above, the base pad can be made of a crystalline material or a metal, as long as the base can be formed at a temperature below that in which the performance of the abrasive particles is significantly affected. The abrasive elements according to the invention can be applied to any suitable form of coated abrasive. Generally, however, the greatest advantage is found when the elements are used to form an abrasive disk. In such a case, it is preferred to form the elements with the base pad in the form of a circular disk with a diameter that is less than about 40%, and preferably less than about 25%, of the diameter of the disk. The elements are arranged around the disk in such a way as to provide the maximum usable usable surface. These could be in the form of two or more rings of elements around the disk, with one ring inside the other, optionally with the elements radially misaligned with respect to the elements in the adjacent rings.

DESCRIPTION OF THE DIBU30S Figure 1 is a cross-sectional view of an abrasive element according to the invention.

I to Figure 2 is a plan view of an abrasive disk comprising abrasive elements conforming to the invention.

DESCRIPTION OF THE PREFERRED MODALITY OF THE INVENTION The invention is now described with reference to the accompanying drawings which are for purposes of illustration only and are not intended to imply any necessary limitation on the scope of the invention. Referring to the drawings, an abrasive element 1 comprises a base pad 2 and a plurality of filamentary particles 3 having one end of each particle rooted in the base. In Figure 2, the elements illustrated in Figure 1 are shown arranged in two concentric rings on the surface of a disc 5 having a central junction location 5. In a particular embodiment of the invention, as depicted in the drawings, a deposit of a phenolic resin is prepared in a round mold and filamentous abrasive particles formed from a sol-gel seeded with alumina by a process such as that described in USP 5,090,968, which have a length of 4 mm and a diameter of 0.5 mm, were applied by UP coating on the surface of the resin which is then cured until it is stable dirnensionally., thus forming an abrasive element suitable for use in the invention. Several such elements are then placed on a padded woven fabric backing material, coated with a forming backing of the same phenol resin from which the base pad of the elements is formed. The elements are arranged in concentric circles around the circumference of the disc as shown in Figure 2. The resin formed is then cured and the sizing coating is applied on the top of the abrasive elements and cured. The abrasive disc formed in this way is an effective tool for a wide variety of gas applications.

Claims

NUVEPñP DE Lñ INVENCIÓN CLAIMS

1. - A coated abrasive having a plurality of abrasive elements each comprising a base pad and a plurality of abrasive particles each adhered to a surface of the pad, said elements being adhered to a support material in a with default configuration.

2. A coated abrasive according to claim 1, further characterized in that the abrasive elements have base pads in the form of a circular disk.

3. An abrasive coated in accordance with claim 1, further characterized in that the base pad is made of the same material as the open particles.

4. A coated abrasive according to claim 1, further characterized in that the abrasive element is adhered to the support material in a predetermined configuration.

5. A coated abrasive according to claim 1, in the form of a disc in which the abrasive elements are disposed in one or more concentric circles around the periphery of the disc.

6. A coated abrasive according to claim 1, further characterized in that the abrasive particles are formed from an alumina sol-gel.

7. A coated abrasive according to claim 6, further characterized in that the alumina sol-gel is a < -ol - sown alumina gel.

8. A coated abrasive according to claim 1, further characterized in that the abrasive particles are filamentous abrasive particles.

9. An abrasive coated in the form of a disc comprising a support material and a plurality of abrasive elements, each element comprising a base pad and a plurality of filamentous abrasive particles seeded with alumina sol-gel, each adhered by an extremity to a surface of the pad, said elements are adhered to the support material in a plurality of concentric circles.