US2431258A

US2431258A - Coated abrasive article and method of manufacturing the same

Info

Publication number: US2431258A
Application number: US645635A
Authority: US
Inventors: Henry P Kirchner
Original assignee: Carborundum Co
Current assignee: Unifrax 1 LLC
Priority date: 1946-02-05
Filing date: 1946-02-05
Publication date: 1947-11-18
Anticipated expiration: 1964-11-18

Description

Nov. 18, 194,7. H. P. KIRCHNERJ COATED ABRASIVE ARTICLE AND METHOD OF MANUFACTURING THE SAME Filed Feb. 5, 194@ Env/enfer Henry Kirchner fifor gy Patented Nov.v 18, 19.47

COATED ABRASIVE ARTICLE AND METHOD MANUFACTURING THE SAME Henry P. Kirchner, Niagara Falls, N. Y., assignor to The Carborundum Company, NiagaraFalls, N. Y., a corporation of Delaware Application February 5, 1946, Serial No. 645,635

This invention relates to improved abrasive articles and to a method of manufacturing the samef It is particularly concerned with coated abrasive articles in which the backing comprises discs are very likely t crack when they are pulled up against the supporting pad by the nut I4. Likewise,if the disc has a curvature such that the abrasive side is concave, it will not lie snugly vulcanized ber, and especially with discs made against the supporting pad and is very likely to from such articles. catch against the work and tear. f

Abrasive discs of the kind with which this in- It has been found by experience that a desirvention is particularly concerned have been deable curvature for the disc is such that the height scribed and claimed in a patent to Richard P. of the cord of a disc 9% inches in diameter, which Carlton Re. 20,946. They are made by coating l0 is a size which is very commonly used, shall lie either vulcanized fiber alone or the cloth side of within the range of about 1,4, inch to about-1 inch, a combination of cloth and vulcanized ber and and preferably shall be about to 5A; inch. l Very large numbers of such articles have been, e In order to obtainl this desired degree of curvaand are being, made. They are used for a great ture it is common practice in the abrasive lndusvariety of purposes, such as the removal of excess l5 try to cure the adhesive which is used for attachmaterial from the welds on automobile bodies and ing the abrasive grains to webs of the backing for smoothing sheet material such as automobile material with the webs wound into rollsY of such fenders and refrigerator boxes. diameter that the curvature of the completed ar- The method bywhich these discs are commonly ticle falls within the desired range. l After the used is described and claimed in anumberof patmaterial has been thus treated t0 Set the adents. including a, patent to Herbert R. Stratford hesive the discs are stamped from the web ma- No. 1,686,938. Their construction and method of terial. use have been illustrated in the accompanying Although it is possible by this process to make l drawings, wherein: discs which are initially of the desired curvature, 4Fig-ure 1 is a Side elet/anon of a disc made ac- 25 a great deal 4of trouble is experienced by abrasive cording to one modicatlon of the present lnvenmanufacturers by reason of the fact that vulcantion; ized ber is very susceptible to changes. in at- 'Figure 2 is a side elevation of a disc embodying mOSpheric moisture eentent, Particularly When a second modification of the invention; and one side of the material has been coated as is the Figure 3 illustrates the manner in which the 30 case with the abrasive discs of this invention. It disc is employed. l has been found, for example. that vulcanized liber .As will be seen by reference t0 Figure 3, the manufactured and sold by the Spaulding Fiber discs are mounted on a rotatable shaft I3 by Company of Tonawanda, New York, under the means of a nut Il which screws into the end of trade-mark Armite, Which has been eXlJOSed t0 the shaft and pulls the disc against a supporting the air at 70 F. at 50% relative humidity conpad Il which is commonly made of felt or soft talns 5.5% moisture whereas the same fiber exrubber. The pad is attached to the spindle I3 posed to air saturated with moisture contains through a supporting element l2, which is ccm- 17.6% water. The ber is therefore a relatively monly made of steel and is screwed tightly onto hysroscopic material and unfortunately when the the outside of the spindle I3. As illustrated in 40 moisture content of a n-ber which has been coated the drawing, in use the discs are applied to the onone side changes, the coated article curls. A workpiece I5 at a slight angle so that only a, porreduction in the moisture content causes the ber tion of the periphery of the disc is in contact to curl with the coated side convex while -an inwith the work at any particular instant. It will l crease in moisture produces the opposite effect be apparent thatv the construction and method of and causes the Vinitially Curved disc t0 become us'e of the disc are such that a disc backing must either fiat orl concave on the coated side. .As has bevery tough and relatively stiff though flexible. been Pointed Out above. either an extreme amount In order to make the disc it snugly against the of curvature with the abrasive side convex or a supporting pad II it is desirable that it should reduction in curvature below the minimum limit normally have a slight curvature with the abra- 50 0f about V4 inch abreSiVe-eOnVeX makes the discs'- sive coated side convex so lthat when the nut -II unSatiSfeetOl'yis pulled into the spindle I3 the disc will be caused It is accordingly an object of the present into hug the pad by reason of its springlike nature vention to provide a method of stabilizing abracaused by the slight curvature. On the other sive discs having a backing 6011191181118 Vulcanhand, if the curvature of the disc is .too great, the

ized fiber so that they are substantially unaffected by changes in the atmospheric conditions to which they are exposed. Another object of the invention is to provide a method of treating abrasive discs to obtain a curvature in the desired `direction and of a predetermined amount. Still anotherobject of the invention is to provide abrasive discs which have a predetermined amount of `curvature and which are substantially unaffected `by changes in atmospheric 'moisture' content with a sheet yof material which is impermeable to moisture vapor. I accomplish this by any of several methods, one very satisfactory method being to dry the articles to such an extent that they assume an excessive amount of abrasive-convex curvature and then apply the water vapor-impermeable material by means of a water-soluble adhesive. One method winch I have employed very successfully is to cut the abrasive discs from the web material, dry them until the, moisture content is-of the order of about -5.5%, as by heating in an oven for 21/2 hours at 125 F., and then attaching a disc of paper-'coated metal foil with the paper side against the vulcanized ber. One such foil material which I have found to be satisfactory is made by the Reynolds Metal Company vand identified as Mat Silver #30 Unifoil. This material consists of a sheet of paper about .002 inch thick adhesively attached to an aluminum foil which is about .001 inch thick.

In carrying out the process I rst coated the paper side of the Unifoil with ordinary mucilage which I allowed to dry and I then moistened the mucilage with water to make it tacky and pressed it against the back of a disc 91/8" in diameter. I found that the small amount of water used to moisten the mucilage, which brought the moisture content of the disc to about 5.545%. was sufficient to make the disc assume a curvature such that the height of the cord formed by the y curled disc was inch.

Referring now to the drawings:

In Figure 1 there is shown a side elevation of a disc having a backing l consisting of vulcanized fiber to one side of which a layer of abrasive grains 2 is attached by a bond 3. The other side cf'the ber is providd with a layer of water` vapor-impermeable foil 4 cemented to a paper layer 5 which is attached to the vulcanized ber by an adhesive 6.

' In Figure 2 the backing consists of a layer of vulcanized fiber i having attached to one surface a layer of cloth 1 by an adhesive 8 and to the other surface a. water vapor-impermeable film 4 which is attached directly to the fiber by adhesive 6. As in Figure 1, the abrasive grains 2 are attached to the backing by a. bond 3, in this instance the grains being directly applied to the cloth 1. The discs are provided with an arbor hole 9 for attaching to the spindle I3 in the manner illustrated in Figure 3. The amount of curvature of the discs shown in Figures 1 and 2 is indicatedby` the height hl of the cord formed by the curved disc.

Although I have found the paper coated aluminum foil to be very satisfactory. I may use other metal foils such as copper and tin and I have also made discs which are stable'to changes in atmospheric moisture content by substituting for the metal foil other water lvapor-impermeable materials such as a sheet of plasticized vinylidene chloride which is made by the Dow Chemical 5 company and sold under the trade name Saran,

or by using a specially prepared paperlike product .which is made by the Riegel Paper Corporation of New York city and sold under the designation M. P. Heat Seal Laminated Amber Di- 10 afane. Still another product ofl the Riegel Paper vCorporation which has been found t0 be satisfactory for use in our invention is one sold under the designation M. P. Heat Seal Pouch Stoc In applying these other materials I may either preliminarily cement them to a. sheet of poper as was described with respect to the aluminum foil, or I may attach them directly tothe disc by a suitable cement as` shown in Figure 2 of the drawings. f

In the latter case the disc is brought to the desired curvature before attaching the water vapor-impermeable lm because it is necessary to use amadhesive made up with an organic solvent and such solvents do not materially affect the curvature of the ber. For example, the Saran" film may be attached by using a rubber cement which is substantially free from water.

It is to be understood that the paper-foil lm of Figure 1 may be used where the backing is a cloth-fiber combination, as shown in Figure 2, or that the film may be used without paper, as

shown in Figure 2, where the backing consists only of vulcanized liber. v

Where I use a metal foil such as aluminum foil I have found that the foil is somewhat fragile- Iand at times may be pricked or scratched, for example when it is put into contact with abrasive coated surfaces. To prevent such rupturing of the metal foil I nd that it is sometimes desirable 4 to apply a coat of lacquer over the metal foil.

One such lacquer which I have found to be satisfactory has the following composition, the proportions being parts by weight:

Parts 1/2 sec. nitrocellulose 16 Estergum- 6 'Iricresyl phosphate 3 Butyl alcohol 11 Ethyl allnhnl 7 Butyl acetate 25 Toluol 32 In applying suchlacquer I first dilute the composition described above with an equal part of 56 ethyl acetate and then spray this thinned lacquer over thevmetal foil. I have found that one coat ,is suiiicient for my purpose and that a satisfactory weight is in the range of 3/4 to 11/2 grams of the lacquer solids per 100 square inches of foil.

e0 'Ihis corresponds to about 6 to 12 grams of the thinned lacquer per 100 square inches of surface since the' thinned lacquer contains U15/2% soivents.

It will be apparent that I may apply the lacquer either before or after the foil has been stuck to the disc. It will also be apparent that although I` have described the application of the lacquer as a spray, it may be put 'on otherwise as by roll coating, in which case a lacquer may be employed of the `composition given in the formula above and the thinning described for spraying is unnecessary.

As I have indicated, the .backing may be either wholly vulcanized fiber or it may be a combination which includes vulcanized ber such as a adhesives.

- combination of vulcaniz also use other backing materials which include vulcanized fiber, such as a combination of cloth,

paper and vulcanized liber, as is described and claimed in my Patent No. 2,320,139 or I may even use conventional backings such as paper or cloth where the coated articles are to be employed for other purposes as in the manufacture of abrasive belts, sheets, cones or the like. Where ber I backing by any suitable adhesive such as glue or a synthetic resin or by a combination of different For example, they may be directly attached to the backing by a so-called making coat of glue and then a second or sizing coat of a synthetic resin such as a phenol-aldehyde condensation` product may be applied over the abrasive grains and the glue making coat. Where a combination backing is used, the cloth backing may be cemented to the iiber by any suitable adhesive such as glue, a phenol-aldehyde resin, or a urea-aldehyde resin.

Although I have .described my invention by reference to certain specic materials and methods, it is to be understood that, the invention is not to be limited to the specic details described and shown in the drawings but rather is to be-considered of the scope defined in the following claims.

I claim 1. In a method of making an abrasive disc the steps which comprise bonding a layer of abrasive grains to a backing comprising vulcanized fiber, forming a disc from the abrasive coated backing, drying the article to such an extent that the ed ber and cloth. I may' abrasive coated side of the article is convex and the article has a radius of curvature which is smaller than that desired in the finished article, and attaching a sheet of paper adhesively joined to a lm which is substantially impervious to water vapor on the vulcanized ber on the side of the backing which is opposite the abrasive coat-l ing by an adhesive containing water whereby the water in the said adhesive penetrates the vulcani'zed ber and causes the article to assume a predetermined curvature of greater radius than that of the dried article.

2. In a method of makin-g an abrasive disc the steps which comprise bonding a layer of abrasive materials to a web of backing material comprising vulcanized fiber, cutting a disc from the abrasive coated web, drying the disc to such an extent that the abrasive coated side of the disc is convex, and adhesively attaching a preformed iilm which is substantially impervious to water vapor to the vulcanized fiber on the side of the backing which is opposite the abrasive coating.

3. In a method of making an abrasive disc the steps which comprise bonding a layer 'of abrasive materials to a web of backing material comprising vulcanized ber, cutting a disc from the abrasive coated web, drying the disc to such an extent .that the abrasive coated side of the disc is convex and the disc has a radius of curvature which is smaller than that desired in the nished article, and attaching a film which is substantially impervious to water vapor to the vulcanized ber on the side of the backing which is opposite the abrasive coatingy by an adhesive containing water whereby. to increase the radius o1 steps which comprise bonding a layer of abrasive materials to a web of backing lmaterial com- Drising vulcanized ber, cutting a disc from the abrasive coated web, drying the disc to such an extent that the abrasive coated side of the disc is convex and the disc has a radius of curvature which is smaller than that desired in the iinished article, and attaching a sheet of paper adhesively Joined to a sheet of metal foil to the vulcanized fiber on the side of thel backing which is opposite the abrasive coating by a water-soluble adhesive, the amount of water in the adhesive being such as to cause the finished disc to assume a curvature such that the height of a cord formed by a disc about 9 inches in the range of about A to 1 inch.

5. In a method of making an abrasive disc the steps which comprise bonding a layer of abrasive materials to a web of backing material comprising vulcanized ber, cutting a disc from the abrasive coated web, drying the disc to such an extent that the abrasive coated side of the disc is convex and the disc has a radius of curvature which is smaller than that desired in the nished article, and attaching a. sheet of paper adhesively joined to a sheet of aluminum foil to the vulcanized iiber' on the side of the backing which is opposite the abrasive coating by a water-soluble adhesive, the amount of water in the adhesive being such as to cause the finished disc to assume a curvature such that the height of a cord formed by a disc about 9 inches in diameter is within the range of about 1A to 1 inch. f

6. An abrasive disc comprising a backing comprising vulcanized ber, a layer of abrasive grains bonded to one side of the backing, anda lm which is substantially impervious to water vapor adhesively attached to the vulcanized ber on the side of the backing which is opposite the abrasive coating, the moisture content of the vulcanized fiber being such that the disc has a curvature in such direction that the abrasive surface is convex and of such an amount that the height of a chord formed by a disc about 9 inches in diameter is within the range of about V4 to 1 inch, the vulcanized ber being so sealed in by kthe bond for the abrasive grain on the one side stantially impervious to water vapor attached to the vulcanized ber on the side of the backing which is opposite the abrasive coating by a water-soluble adhesive, the moisture content of the vulcanized iiber being such that the disc has a curvature in such direction that the abrasive surface is convex and of such an amount that the height of a chord formed by a disc about 9 inches in diameter is within the range o! about 1/4 to 1 inch, the vulcanized ber being so sealed in by the bond for the abrasive grain on the one side and the nlm on the back that the curvature o! the disc remains within the designated range even when the disc is exposed to wide variations in atmospheric moisture conditions.

8. An abrasive disc comprising a backing comdiameter is within prising vulcanized ber, a layer of abrasive grains bonded to one'side of thebacking. and a layer of paper adhesively joined to a sheet of metal toil v the disc has a curvature in such direction thatl the abrasive surface is convex and of such an amount that the height of a chord formed by a disc about 9 inches-in diameter is within the range of about Wto 1 inch, the/vulcanized ber being so sealed in by the bond for the abrasive grain on the one side and the lm on the back that the curvature of the. disc remains withinv the designated range even when the' disc is exposed to wide variations in atmospheric lmoisturen:

conditions.

9. An abrasive disc comprising abackirrg comprising vulcanized ber, a layer of abrasive grains bonded to one side of the backing, and a layer of paper Vadhesive joined foil attached to the vulcanized ber on the side of the backing which is oppositevl the abrasive coating by a water-soluble adhesive, the moisture content o1 the vulcanized ber being such that i the disc has a curvature in such direction that the abrasive surface is convex and of such an amount that the height of a chord formed by a disc about 9 inches in diameter is within the range of about 1/4 tol inch, the vulcanized ber being so sealed in by the bond for the abrasive grain on the one side and the lm on theI back that the curvature of the disc remains rwithin thel designated range even when the disc is ex-Y posed to wide variations in atmospheric moisture l conditions.

10. An abrasive disc comprising a backing comprising vulcanized ber and cloth. a layer of abrasive grains bonded to the cloth, and a lm which is substantially' impervious to water vapor .adhesively attached to the other side of the vulcanized ber, the moisture content of the vulcanized ber being such that the disc has 'a curvature in such direction that the abrasive surface is convex and of such an amount that the height of a chord formed by a disc about 9 inches in diameter is within the range of about 1A. to 1 inch. the vulcanized ber being so sealed in by the bond for the abrasive grain on the one side and the lm on the back that the curvature of the disc remains within the designated range even when the disc is exposed to.wide variations in i atmospheric moisture conditions.

to a sheet oi aluminum tlf 2,431,258

11. An abrasive disc comprising a backing consisting of vulcanized ber, a layer of abrasive grains bonded to one side of the ber, and a lm which is substantially impervious to water vapor adhesively attached to the other side of the vulcanized ber, the moisture content of the vulcanized ber being. such that the disc has a curvature in such direction that the abrasive surface is'convex and of such an amount that the i/ height of a chord formed by a disc about 9 inches ,f ,in diameter is within. the range of about V4 to 1 f?, inch, the vulcanized ber being so sealed in byA the bond for -the abrasive grain on the one side and the lm ong' the back thatthe curvature of the disc remains within the designated range even when the `disc is exposed to wide variations atmospheric moisture-conditions. 12. An abrasive disc comprising a. backing com prising vulcanized ber, a layer of abrasive grainsl bonded to one side of the backing, a layer o1 pal per adhesively joined to a sheet of aluminum foil attached to the vulcanized ber on the side of the backing which is opposite the abrasive coatlacquer on'the exposed side of the aluminum foil, the moisture content of the vulcanized ber being such that the disc has a curvature in such direction that the abrasive surface is convex and of such an amount that the height of a chord formed by a disc about 9 inches in diameter is within the range of about to llincl'r'thel f vulcanized ber being so sealed in by the bond ,for the abrasive grain on the one side and the lm on the back that the curvature of the disc remains within the vdesignated range even when the disc is exposed to wide' variations in atmospheric moisture conditions.

HENRY fP. KIRCHNER.

4 REFERENCES CITED The following referencesare of record in the l Number Name Date 2,269,661 Gurwick Jan. 13, 1942 2,190,479 Moore Feb. 13, 1940 1,759,168 Okie May 20, 1930 2,152,392 Tone Mar. 28, 1939 1,966,473 Wooddell a July` 17, 1934 2,085,211 y BuddSet al June 29, 1937 ing by a water-soluble adhesive, and a coat of