US2532248A

US2532248A - Fibrous polishing device

Info

Publication number: US2532248A
Application number: US32506A
Authority: US
Inventors: Frederick A Upper; Richard A Baumgartner
Original assignee: Carborundum Co
Current assignee: Unifrax 1 LLC
Priority date: 1948-06-11
Filing date: 1948-06-11
Publication date: 1950-11-28
Anticipated expiration: 1967-11-28

Description

Patented Nov. 28, 1950 UNITED STATES PATENT OFFICE FIBROUS POLISHING DEVICE Frederick A. Upper and Richard A. Banmgartner, 'Niagara Falls, N. Y. assignors to The Carborundnm Company, Niagara Falls, N. Y., a corporation of Delaware Application June 11, 1948, Serial No. 32,508

7 Claims. 1

This invention relates to laminated fibrous polishing or honing devices such as wheels, sticks, and other shapes comprising layers of felted fibrous sheet material which are adhesively combined to provide a suitably resilient fibrous body which as made containsno abrasive material but which in use usually is charged with the desired finely divided abrasive in liquid, paste, or solid form to produce the required abrasive action.

Heretofore, non-abrasive fibrous polishing wheels and the like composed of layers of fibrous sheet material held together by a resilient material such as a natural or synthetic rubber have been found unsatisfactory for the reason that they have failed to stand up in use. on the other hand, similar articles when made with a heat-hardenable resin as the bonding material have met with no success because of the harshness of cutting action and the failure to produce a satisfactory finish upon the work being polished.

It is an object of the present invention to provide non-abrasive, fibrous polishing devices having improved polishing action.

It is also an object of the present invention to provide improved polishin devices of laminated structure, which provide not only a satisfactory polishing action but which do not break down prematurely in use.

Other objects and advantages of the invention will become apparent from the following description. i

In order that the invention may be fully understood, reference is made to the drawing, in which:'

, Figure 1 depicts a top plan view of a polishing wheel made in accordance with the present invention; and

Figure 2 is a vertical. diametrical cross section through the line 2-2 of Figure 1.

We have found that highly satisfactory laminated, fibrous polishing devices such as polishirig wheels, honing sticks and the like can be made from sheets of carded or felted fibrous material when some of the fibrous sheets are impregnated with a heat-hardenable binder such as a thermosetting, phenol-formaldehyde resin, and other layers of the fibrous sheet material are impregnated with a permanently resilient binder such as a coagulated polychloroprene latex. In order to provide the most uniform polishing action throughout the device the body of the article is usually formed by alternating layers of the unwoven fibrous sheet material containing the heat-hardenable binder with layers of similar sheet material containing the permanently resilient binder. By so alternating the two types of fibrous sheet material making upthe body of the article, the polishing quality of the resulting laminated structure is consistent and uniform throughout.

A fibrous sheet material which has been found highly satisfactory for carryin out the present invention is that described and disclosed in U. S. Patent No, 2,055,410. The fibrous sheet material therein disclosed consists of a carded fibrous web produced by a process in which the sheet material is dry laid. During the course of manufacture the fibers of the sheet material are up-ended and disarranged from the normally parallel position usually assumed in a carding or combing operation so that the individual fibers of the sheet material are interwoven and intermingled in all directions to form a strongly interlocked fibrous structure in which the desired impregnating adhesive used to hold the fibers of the sheet in compact condition is introduced into the web of material after the fibers have been suitably interwoven but usually prior to or at the time of compacting of the sheet material. In making articles of the present invention a supply of the fibrous sheet material which has been impregnated with a heat-hardenable resin, and a supply of similar fibrous material impregnated with a resilient binder such as polychloroprene latex, are obtained. The two materials are died out or cut into pieces of the desired shape and the pieces of the two materials assembled in alternating arrangement and hot pressed, whereupon the two impregnating adhesives serve jointly as the laminating adhesive to hold the various layers of material together. The presence of the two types of adhesive in the final article in the manner provided in the present invention produces a polishin effect in the final article unobtainable by the use of either adhesive exclusively. It is not fully understood how the two adhesives coact to produce such a. result although it is surmised that the heat-hardened resinous binder, dispersed as it is through the body structure, serves to preserve and hold up the fibrous material during polishing operations and yet provide some degree of friability to produce a gradual breakdown of the polishing surface during use. 0n the other hand, the permanently resilient constituent of the composite bo jding material contained within the overall body of the polishing device appears to coact with the heat- 3 hardened constituent of the binder to modify the hardness characteristics of the resin without being so intimately blended therewith as to interfere with or destroy the desirable qualities of the resin. As a result. the resinous material does not render the abrasive action too harsh for polishin purposes and yet is allowed to contribute highly satisfactory breakdown characteristics to the article.

Referring further to the drawing. a polishing wheel 3 provided with an arbor hole 4 is composed of a plurality of layers or plies of sheet material 5 impregnated with a heat hardened resinous binder and alternated with a plurality of layers of fibrous sheet material 8 impregnated with a permanently resilient rubber bond.

A non-abrasive laminated fibrous polishing wheel of the type shown in Figures 1 and 2 is made as follows:

A non-abrasive, carded cotton fiber sheet materialsuch as that described, in U. S. Patent 2,055,410 which has been impregnated with a liqliid heat-hardenable phenolic resin, such as that made and sold by the Bakelite Corporation of Bloomfield, New Jersey, under the trade desigjnation "Bakelite BR5995, and which has a resin 'content amounting to 20-35% dry weight based- 'on the total weight of the sheet material is diedout into a number of disc shaped pieces having an outside diameter of 3%" and a central arbor hole 1" in diameter. A similar fibrous sheet materialimpregnated with 5-10% by weight of a coagulated polychloroprene latex is also died out into a number of disc-shaped pieces also of 3%" outside diameter'and having a 1" central arbor hole. The disc shaped pieces of the above two materials are then assembled in alternating arrangement and aligned on a 1" diameter arbor pin and prepressed cold to an apparent density which is preferably 16-20 grams per cubic inch. The pre-pressed shape is then hot pressed between polished metal plates at 260 F. and 500 pounds per square inch for 15 minutes, employing shims .312" thick to limit the extent of compression of the material during the hot pressing operation Upon removal from the hot press the resulting polishing wheel is allowed to cool and then finished to size in accordanc with usual dressing practices.

Although in the above description the polishing wheel was made with an equal number of layers of each material with the sheets of material in alternating arrangement it is possible without departing from the spirit of the present invention to allow the number of sheets of one material to predominate over the number of sheets of the second material. However, the ratio of the sheets of resiliently bonded material to sheets of resinous bonded material should be kept within the range of 1:3 to 3:1 in number in order to obtain satisfactory results.

Other heat-hardenable resinous materials may be used in place of the phenolic resins heretofore mentioned such as urea resins, melamine resins and other thermosetting resinous materials. Also, the resilient binder, instead of polychloroprene latex, may be any natural. or synthetic rubber material such as butadiene-styrene copolymers, butadiene-acrylonitrile copolymers and the like or it may be any one of a number of thermoplastic resins such as the styrene resins, methmaterial containing a rubber bond, the piles of v acrylates and the like. The resilient binder can also be modified by use therewith of modifying ingredients such as casein or the like.

Having described the invention, it is desired toclaim:

1. A laminated fibrous polishing device comprising layers or non-abrasive fibrous sheet material bonded with a resilient binder alternated with layers of non-abrasive fibrous sheet material bonded with a non-resilient binder, the layers of said article being adhesively combined.

2. A laminated polishing device comprising a plurality of plies of non-abrasive, fibrous sheet material containing a heat-hardened resinous bond intercalated with piles of non-abrasive, fibrous sheet material containing a resilient bond, the plies of said device being adhesively combined.

3. A laminated polishing device comprising a,

said device being adhesively combined.

4. A laminated polishing device comprising a plurality of plies of non-abrasive, fibrous sheet material containing a heat-hardened phenolic resin intercalated with plies of non-abrasive, fibrous sheet material containing a polychloroprene bond, the plies of said device being adhesively combined.

5. A laminated polishing device comprising a plurality of adhesively combined plies of nonabrasive, fibrous material in which various of the plies throughout the device contain a resilient binder and the remainder of the plies contain a heat-hardened resin.

6. A laminated fibrous polishing wheel comprising a composite of resiliently bonded nonabrasive, fibrous discs and non-resilient bonded non-abrasive, fibrous discs adhesively combined to form a unitary structure.

7. A laminated fibrous polishing device comprising layers of non-abrasive, carded cotton fibrous sheet material adhesively combined, in which some of the layers are impregnated with a heat-hardened phenolic resin and the other layers are impregnated with a resilient binder such as polychloroprene.

FREDERICK A. UPPER. RICHARD A. BAUMGARTNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 334,671 Laughton Jan. 19, 1886 341,925 Lemassena May 18, 1886 704,789 Elson July 15, 1902 895,641 Hyatt Aug. 11, 1908 1,435,721 McIntosh et al. Nov. 14, 1922 1,822,856 Dirkes Sept. 8, 1931 1,932,104 Hepp Oct. 24, 1933 2,078,437 Anderson Apr. 27, 1937 2,284,715 Benner et al June 2, 1942 2,284,716 Benner et a1 June 2, 1942 2,335,902 Ball et al. Dec. 7, 1943 2,375,263 Upper May 8, 1945 2,378,386 Baumgartner June 19, 1945