Abstract:
A flexible abrasive finishing article including a backing of fabric or paper having first and second major surfaces with abrasive particles adhesively secured to said first major surface and a layer of cyanoacrylate based material substantially covering the second major surface. The method of making a flexible abrasive finishing material including the steps of applying a layer of cyanoacrylate based material to a surface of a backing material opposite the surface to which abrasive particles are adhesively secured and covering said cyanoacrylate material.

Description:
RELATED APPLICATIONS 
     This application is based upon Provisional Patent Application No. 61/271,771 filed on Jul. 27, 2009, Reinforcing Cloth &amp; Paper Abrasive Discs with Cyanoacrylate Adhesive, and hereby claims the benefit of the filing date thereof. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to flexible abrasive products having a backing material of fabric or paper having abrasive particles adhered to one surface thereof and a layer of cyanoacrylate based material coated on the opposite surface thereof. 
     BACKGROUND OF THE INVENTION 
     Coated abrasive articles generally contain an abrasive material typically in the form of abrasive grains bonded to a backing by means of one or more adhesive layers. Such articles usually take the form of sheets, discs, belts, bands and the like which can be adapted to be mounted on pulleys, wheels or drums. Abrasive articles can be used for sanding, grinding or polishing various surfaces of, for example only, and not by way of limitation, steel and other metals, wood, wood-like laminates, plastic, fiberglass, leather or ceramics. 
     Coated abrasive articles are used industrially, commercially and by individual consumers to prepare any of a variety of materials for use or for further processing. Exemplary uses of such abrasive products include: preliminary preparation of a surface before priming or painting, cleaning the surface of an object to remove oxidation or debris, and grinding or abraiding an object to obtain a specific shape, to upbraid a surface to clean or facilitate a bonding or coating such as paint, or to provide a desired surface finish especially a smooth or otherwise a decorative finish. 
     Many abrasive articles are used as discs in grinding assemblies. A typical such abrasive, sanding or grinding assembly includes: a back-up pad or support pad made from a resilient and reinforced material such as rubber or plastic, an abrasive disc which is typically adhesively or hook and loop mounted on the back-up pad, or otherwise secured by appropriate fastening members attached to the abrasive disc, and a rotatable shaft and cap for mounting the abrasive disc and back-up pad to an appropriate electric or air pressure driven power tool. In use, the shaft of the assembly is rotated by the power tool and the abrasive coated surface of the disc is pressed against a work piece with considerable force, thus the disc is subjected to severe stresses. 
     The backings used in coated abrasive articles are typically made of paper, polymeric materials, cloth, non-woven materials, vulcanized fiber, or combinations of these materials. Many of these materials are not appropriate for certain applications because they are not of sufficient strength, flexibility or impact resistant. 
     The present invention is directed to coated abrasive finishing articles which utilize fabric or paper as the backing material. Such backing materials when utilized as coated abrasive discs used in a grinding operation such as: weld grinding, contour grinding, and edge grinding it has been found that the backing material, particularly around the outer edges of the disc, tends to deteriorate rather rapidly thus causing a very short useful life for the abrasive disc. The deterioration and short life is contributed to by the limited radial strength of the fabric and/or paper backing 
     In many instances coated abrasive finishing articles have an additional coating or layer applied to the surface of the backing material opposite that to which the abrasive articles are secured in order to provide additional lifetime to the coated abrasive disc. It has, however, been found that when such additional coating or laminations are applied to the surface of the backing material that the flexibility of the abrasive disc is compromised. That, therefore, results in the inability of the operator to utilize the abrasive disc to abrasively finish surfaces which have curvatures thereto of any significant degree. 
     Thus there exists a need for a flexible abrasive finishing article which has a tailored cutting ability, a long useful life which can be made in a simple method and does not in anyway compromise the flexibility of the abrasive finishing article. Particularly, such abrasive finishing articles are formed as discs. 
     SUMMARY OF THE INVENTION 
     A flexible coated abrasive finishing article having a flexible backing having first and second major surfaces, an abrasive layer secured to the first major surface, and a layer of cyanoacrylate based material substantially covering said second major surface. 
     The present invention also includes the method of making a flexible coated abrasive article which includes the steps of providing a flexible backing having first and second major surfaces on opposite sides thereof, an abrasive layer secured to the first major surface, and applying a coating of cyanoacrylate based material to such second major surface, and curing said cyanoacrylate material to provide a coating substantially covering said second major surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a coated abrasive article according to the present invention.  FIG. 1  is schematic in nature to reflect construction according to the present invention; 
         FIG. 2  is an enlarged fragmentary side cross-sectional view of a coated abrasive article according to the present invention taken along the lines  2 - 2  of  FIG. 1 ; 
         FIG. 3  is an enlarged fragmentary side cross-sectional view of an alternative embodiment of a coated abrasive article according to the present invention; 
         FIG. 4  is an enlarged fragmentary side cross-sectional view of a further embodiment of a coated abrasive article according to the present invention; 
         FIG. 5  is a side view of a coated abrasive article according to the present invention and attachment system secured to the back surface thereof; and 
         FIG. 6  is a schematic view of a system for making coated abrasive material to be used in constructing coated abrasive finishing articles as illustrated in  FIGS. 1 through 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As required, detailed descriptions of the present invention are provided herein. In general, the detailed descriptions are to be considered as exemplary only. Therefore the invention is not to be interpreted as limited to the specific formulations, arrangements and method identified and described, except as limited by the claims. 
       FIG. 1  illustrates a front view of a circular disc  10  which incorporates the construction as illustrated in  FIG. 2 . Circular disc  10  is representative of a working surface  12  of a coated abrasive disc according to the present invention. The working surface  12  is also referred to as a front surface or a top surface and generally represents the surface used for abraiding work pieces. The representation shows two general regions  14  and  16 . Region  14  includes abrasive material in the form of abrasive grains  18  adhered to the working surface  12  of the backing of the circular disc  10 . Region  16  is a center aperture in the circular disc  10  for use in mounting the disc  10  on a rotatable shaft of a power driven grinding tool for rapidly rotating the disc  10  as the working surface  12  is applied to the surface which is to be abrasively finished. It will be understood by those skilled in the art that various attachments may be used which may or may not require a center aperture. 
     Generally the diameter of the disc will be within the size range of about two to six inches but can vary therefrom. The disc may typically have a center aperture as illustrated, that is the region  16  which is usually about ¼ to ⅞ inches in diameter. Alternatively, however, instead of having a center aperture as illustrated at  16  there may be affixed to the reverse or backside of the disc  10  an attachment system which is utilized for attaching the disc  10  to an appropriate power drive tool such as a random orbit dual action sander. 
     Referring now more particularly to  FIG. 2 , a coated abrasive article  10  according to the present invention includes a backing  20  and a layer  22  of adhesive material. This adhesive material  22  is used to secure an abrasive material such as a plurality of abrasive grains  24  to the working or first major surface  26  of the backing  20 . The layer of adhesive  22  is commonly referred to as a make coat. A second adhesive layer  28  which is commonly referred to as a size coat is coated over the abrasive grains  24  and the first adhesive layer  22 . The purpose of the size coat is to secure and anchor the abrasive grains  24 . A third adhesive layer  30  which is commonly referred to as a supersize coat may be coated over the second adhesive layer  28 . The third adhesive layer  30  is optional and is typically utilized in coated abrasive articles that abraid very hard surfaces such as stainless steel or exotic metal work pieces. 
     The thickness of the backing layer  20  is typically less than about 0.06 inches for optimum flexibility and material conservation. Preferably the thickness of the backing  22  is between about 0.02 and 0.05 inches for optimum flexibility. However, the thickness of the backing layer  20  may be decreased or increased depending upon the particular applicability to which the abrasive finishing article is to be put. As is illustrated in  FIG. 2 , the backing layer  20  is constructed of fabric material both natural and synthetic. It should be understood, however, and will be discussed more in detail hereinafter that the backing layer may also be constructed of paper. 
     The structure above described and illustrated is known in the art and for example, one form thereof is illustrated and described in U.S. Pat. No. 7,344,575 which is incorporated herein by reference. 
     The novel feature of the present invention is that a layer of cyanoacrylate based material  32  is adhered to the opposite or second major surface  34  of the backing material  20 , that is the major surface opposing the first major surface  26  to which the abrasive particles  24  are secured. The thickness of the layer  32  of cyanoacrylate based material is preferably between 0.003 and 0.005 inches although it may be thicker depending upon the particular application to which the abrasive finishing article is to be put. It has been found that the layer of cyanoacrylate based material provides a surprising improvement to the radial strength of the backing material  20  without any loss of flexibility. Such surprising improved radial strength permits the use of larger diameter abrasive discs held on support pads with relatively small diameter fastener flanges. The support pads can be very flexible if desired. It is this improved radial strength of the backing material provided by the cyanoacrylate based layer that allows the utilization of such discs on random orbit/dual action sanders for abrasively finishing contours as well as flat surfaces. The cyanoacrylate coating increases the radial strength such that the periphery of the adhesive disc does not deteriorate for a substantially longer use period even under severe stress. 
     The cyanoacrylate based layer  32  may be any known cyanoacrylate based material. However, it is preferably selected from the group consisting of ethyl cyanoacrylate, methyl cyanoacrylate, butyl cyanoacrylate, beta methoxy ethyl cyanoacrylate, alpha cyanoacrylate, and octyl cyanoacrylate. 
     Referring now more particularly to  FIG. 3 , another exemplary coated abrasive article according to the present invention is illustrated. As is therein shown, the coated abrasive article  36  comprises a backing  38 . The backing  38  may be fabric as is the backing  20  in  FIG. 2 , or alternatively, as will be described in more detail hereinafter, may also be paper. Adhered to the working surface  40  of the backing  38  is a plurality of abrasive grits such as shown at  42  which are distributed throughout a binder  44 . Again, structure as thus illustrated and described is well known in the prior art and described in U.S. Pat. No. 7,344,575 above referred to and is incorporated herein by this reference. In accordance with the novel feature of the present invention, a layer  46  of cyanoacrylate based material selected from the group above identified is secured to the opposite surface  48  of the backing layer  38  and is constructed of the materials and of the thicknesses as above described. 
     Referring now more particularly to  FIG. 4 , there is illustrated an additional embodiment of the present invention which includes a backing layer  50  which is constructed of paper. Attached to the working or first major surface  52  of the paper backing layer  50  is an adhesive layer  54  which is used to secure a plurality of abrasive particles  56  to the working surface  52  of the paper backing  50 . On the opposite or second major surface  58  of the backing layer  50  there is adhered a layer  60  of cyanoacrylate material of the type above referred to and selected from the group above referred to. Again the layer  60  of cyanoacrylate based material provides surprisingly improved radial strength to the paper backing layer  50  allowing it to be used in the manner above described in accordance with the surprising results obtained by the present invention. 
     Referring now more particularly to  FIG. 6 , there is illustrated an abrasive disc  62  having the abrasive particles  64  secured to the working surface thereof and a layer of cyanoacrylate based material  66  secured the opposite surface of a backing layer  68  and extending to the peripheral edge thereof. Also secured to an opposite surface of the backing material  68  is a securing system  70  which is well known in the art and is utilized to secure the disc  62  to an appropriate power tool for rotating the disc as it is applied to a work surface. Alternatively these securing systems may include an appropriate threaded member extending through an aperture in the disc and secured in place by various means known in the art. 
     Referring now more particularly to  FIG. 5 , there is schematically illustrated a system for constructing the abrasive finishing materials from which the disc as illustrated and described above is manufactured. As is illustrated in  FIG. 5  a roll  72  of a backing layer of either fabric or paper having abrasive material adhesively secured to a first major surface  73  thereof is supported upon a support  74  so that the backing material may be pulled in the direction shown by the arrow  76  by appropriate rotating rollers  78  and  80  which grip the material and pulls it from the roll  72 . As the material is pulled in the direction as shown by the arrow  76  a cyanoacrylate based material is deposited from a source  82  thereof through an appropriate conduit  84  onto a second major surface  86  of the backing layer opposite that material. After the cyanoacrylate material is deposited on the surface a scraper  88  spreads the material and evens it out as is shown at  90 . The scraper is preferably manufactured from ultra high molecular weight (UHMW) polyethylene plastic material. As is well known in the art the cyanoacrylate material will cure and set very rapidly and particularly such is the case in the presence of moisture. However, to speed up the manufacturing process an accelerator is applied to the surface  86  of the material upon which the cyanoacrylate based material has been deposited. This accelerator is applied from a source  92  thereof through an appropriate conduit  94  into a chamber  96  through which the backing material having the cyanoacrylate coated thereon is passed. The accelerator which is utilized may be any known to the art, but preferably is toluidine which is disposed within a carrier such as acetone or isopropyl alcohol and one such carrier may be 68% acetone, 14% N butane and 15% propane. Through the utilization of the accelerator the cyanoacrylate based material cures much more rapidly such that by the time it reaches the rollers  78  and  80  the cyanoacrylate is totally cured and no longer has an adhesive-like characteristic. 
     There has thus been disclosed a flexible coated abrasive finishing article having a fabric or paper backing which has abrasive articles affixed to a first major surface thereof and layer of cyanoacrylate based material affixed to the opposite or second major surface thereof which provides surprisingly improved radial strength to the coated abrasive finishing article, as well as a method of manufacturing the same.