Патент USA US2404192код для вставки
July 16, 1946. K. G. RlEs ET AL ABRÁSIVE ARTICLE AND METHOD OF MAKJ-.NG ' 2,404,192 Filed DGO. 29, 1944 g i111.. 1,4 `. _ l ._`. .. . . 'A y / ° ß e o ç ec’gòucQbada „225% f-’o :Zbâv 7i ff) /Zi - . ATTNEY e. Patented July 16, 1946 ' u g 2,404,192.A _UNITED `s'rrrl‘iëz-s `PATENT OFFICE* 2,404,192 A'BRASIVEv ARTICLE AND METHOD OF ‘ AMAKING Kernell G. Ries, Niagara Falls, Norman I’. Robie, Lewiston, and Phyllis von D'oenhoff, Niagara Falls, N. Y., assignors to The Carborundum Company, Niagara Falls, N. Y., a corporation of Delaware ApplicationDecember 2 9, i944,seria1No. 570,314 1 2 . This invention relates tothe lmanufacture of It has, therefore, long been desirable to iind abrasive articles. More particularly, it relates to the manufacture of composite abrasive articles some other more advantageous way of making vsuch articles. Previous attempts to form the comprising two or more resin bonded bodies con aforesaid articles from liquid mixtures of bond taining iillers, at least one of which is abrasive in character and capable of use for abrading pur poses, the individual filler-containing resin bodies being integrally united to form the composite article. The invention also pertains to methods of using liquid or «casting resins as bonds in the 10 and abrasive or other iiller materials have not mety with complete success due to the inability to obtain a satisfactorily strong union between the constituent'parts of the article and at the same time prevent an undesirable mixingor intermin manufacture of such articles in which the con stituent bonded bodies of~ the >article >are inte fillers employed in making the article. satisfactory results that such combination sharp tions. The porous diaphragm allows the liquid, unpolymerized bond to pass through and join-the gling of the various abrasive and/ or non-abrasive , It is an object of the present invention to >pro vide such composite abrasive articles having an grally combined, but with the ñllers of those improved uniformity and structure.. It is a fur constituents sharply segregated one from another. The present invention is especially adap-table 15 ther object to provide improved methods of man ufacturing such articles which will avoid the dis for making dense, ñne grit abrasive articles, as advantages and undesirable features of prior art for example, the making of dual-purpose or com methods as above set forth. v bination honing stones embodying in the one We have found that composite abrasive articles article a resin bonded abrasive body containing a relatively _coarse grit size abrasive ñller for 20 can be made with a plurality of casting composi tions in one article Withoutintermixing ofthe rough grinding and a resin bonded abrasive body powdered ñller materials contained in those cast containing an abrasive filler of much liner par~ ing compositions by the use of .a porous diaphragm ticle size for ñnishing grindingor ñnal sharpen inserted between the different casting composi ing operations. It is highly desirable for most ening stones or hones be as dense and uniform as possible in order to avoid uneven or irregular mixes into a unitary article without permitting cutting action on the instrument being sharpened the intermixing of the various ñller materials. According to the present invention, composite and also that the different size abrasive particles employed in making the article be kept from in-` 30 abrasive articlesof the type described above are made by first formingv a suitable mixture of a termingling one with the other. Heretofore such liquid or casting resin together with the selected combination sharpening stones have been formed by pressure molding relatively dry but ldampened iìller or fillers for forming one part of the article mixtures of the abrasive powder and powdered and placing a sufficient amount of the mixture resin in a hot mold, followed by a prolonged oven 35 in a mold of the desired shape to form that part cure. When prepared according to such pro of the article when set, after which a thin layer cedures, the aggregation of the resin powder into of porous sheet materiaLisuch as -a sheet of coarse larger particles has prevented a thorough wetting filter paper, is placed in the mold over the con and dispersing of the iinely divided abrasive ma Y tents of liquid resin and nller as a diaphragm. terial, and, as a result, the articles so made have 40 A mixture of liquid resin and ñller which is to not been as uniform as could be desired. The constitute the second part of the composite article formation of such articles by pressing methods is then prepared and poured into the mold on top hasalso required the use of costly molds and of the thin sheet of porous material and the entire mold contents are allowed to harden orl set after presses, and required long, high temperaturecures. portion, as for example, the making of a resin which the molded shape is removed from the mold, Vand when desired, given a suitable oven cure'. Other porous materials can be used as the intercalary diaphragm in place of the iilter paper between the constituent resin-ñller mixes so long as the material chosen is permeable to the resin bond and impervious to the different granula bonded grinding wheel having the abrasiveV par ticles confined to that part of thewheel in the fillers The employed liquid resin in bond makingv used. theinarticle. forming thev two vicinity of one or both i‘lat faces or extending radially inward but a short distance from the periphery of the wheel. As in the making of the different parts of the article is usually the same although different resins can be used to form the Certain of the above disadvantages havel also been encountered in the making of composite abrasive articles embodying a resin bonded abra sive 'grinding surface integrally combined with a non-abrasive resin bonded supporting or body various `parts of the article, providing they are combination sharpening stones mentioned above, the manufacture of such articles by pressing pro cedures entails the use of expensive equipment and“ lengthy processes. ' ' cb compatible and are capable of penetrating the porous intercalary sheet material. In the article so formed, it will also be found that if the proper -materials are selected, the granular ñllers con `2,404,192 3 tained in the various parts of the article Will not 4 mixture into-the mold.. >This can be accomplished pass through the porous Vsheet material; so that more easily by forming the article in molds such ` there will be a sharp, clear dividing line betweenv ras those shown in Figures 2 and 3, which are the component parts of the resulting abrasive ' article _with no intermingling of the different ñller ' usually of suitable metallic construction with the exception ofthe diaphragm which is usually aV materials. porous ñbrous sheet material. f ~ A modified method of makingabrasive articles Y Y embodying the principle of the present invention, The mold con struction depicted in Figure 2 consists of a lower mold half I4 and an upper mold half I5 which ' anda method which is particularly adaptable' to Y fits tightly over the lower half I4, holding the forming abrasive articles of the type wherein'the 10 porous diaphragm I 6 in place. The slight out ` » . abrasiveis conñned to a relatively small portion of the'article in the immediate-vicinity of the grinding surface, can -be carried out asA follows. The porous diaphragm or separating medium, such as a layer of ñlter paper, is first coated on one side with a mixture of liquid or casting resin ward iiare I1 of the upper mold half assists in quickly placin-g the upper half in position on the lower half. In use', the lower mold'half I 4 is i'llled with the first liquid, filler-containing Vmixture 15 and the sheet I6 of porous material constituting and abrasive particles, either by first applyinga the diaphragm Vis placed upon the top of the Vfreshly poured contents and held tightly in place coating of the resin to the .filter paper and then while the upper half of 'the mold is placed in addingtheabrasive particles to the adhesively position, thereby holding »the diaphragm ñrmly coated surface or mixing the abrasive particles 20 and accurately in place. The second liquidv mix with the liquid resin and applying the mixture to ture'containing a diiîerent ñlleris then poured the Vi‘llter paper or other porous sheet material. on top of the diaphragm to ñll the upper half of The thus coated filter paper is then suitably the mold. Themold contents are then allowed placed in a mold with the resin and abrasive coat to set, removed from the mold and usually given ed side facing the inner mold surfaces and the 25 an oven cure to mature the resin bond. If de mold ñlled with the liquid resin mixture, usually sired, the mold contents can be subjected to a containing a non-abrasive filler, `which is to con heat treatment at low temperature to hasten set stitute the body of the article, and the mold con tents allowed to set or harden, after which the ting of the resin bond.. strongly combine the abrasivecontaining portion the porous diaphragm 22 tightly in position. The clamps 23 serve to draw the mold lips tightly ' Y The mold in Figure 3, like that in Figure 2, con article so formed is removed from the mold and 30 sists of a lower moldhalf I8 and an upper mold usually‘given'an oven cure. « Again, thevabrasive half I9 and is used similarly. The two mold con-_ e particles will be preserved in position at and ad structions differ fin the Vmanner of holding the jacent to the grinding surface ofthe resulting porous diaphragm in place.? In Figure 3 the upper ' ' article whereas the penetration of the resin bond and lower mold halves I8 and I9 are equipped therefor through the. porous sheet serves to 35 with side lips 20 and 2| which ñt together to hold to the main body of the article with no danger of delamination~ Y , together. Y Y A , In order to better understand the nature of the Figure 4 Ais a side view of a modified abrasive invention, reference is made to the accompanying 40 sharpening stone 24 similar in'shape and con-V drawing, in which: , , . , struction to that depicted in Figure 1 but diñ‘er Figure 1 is a side view of a combination abra ing therefrom in the composition of the two sive sharpening stone made in accordance with bodies 25 and 26 which make up the article.’ The the present invention; , \ abrasive article shown in Figure 4 is composed 45 Figure 2 is a vertical cross-sectional view illus of a resin-bonded, ,Áñne grit size abrasive body 25 f trating one form of .mold set-up used in out the present invention; and v carrying , and a resinous non-abrasive body 26, the two 1 bodies 25 and 26 being separated in a sharp line Figure 3 is a vertical cross-sectional view illus of Vdemarcation between them by reason of the trating a modified form of mold set-up which can presence between the twol bodies of a thin sheet be used in connection With the present invention. 50 of porous filter paper 9 which is permeable to theY ` Figure 4 is aside View of a modiñed form of resin bond I0 but is impervious to the i’ine abra abrasive sharpening` stoneY made in accordance siveparticles I 2 of the resin bonded abrasive body with the present invention. . ‘ 25 and also impervious to any non-abrasive ñller Referring further'to the drawing, Figure 1 is a substances whichV may be incorporated, when de sidefview oi"v aY combination sharpening stone 6 55 sired, in the non-abrasive resinous body 26.’ composed of a coarse grit size abrasive body 'I The following example is given as illustrative. and a iine grit size abrasive body `8, the abrasive A combination abrasive hone, such as that fillers of the two bonded abrasive bodies 'I and shown in Figure 1, was _made having one face 8Vbein~g separated in a sharp line of demarcation suitable for preliminary honing comprising resin between them by reason of the presence between ï bonded 320 mesh size, silicon carbide andthe op- l the two bonded bodies of a, thin sheet of porous ' posite face suitable for finish honing and coml filter paper 9 which'is permeable to the resin bond prising resin bonded, 600 mesh and finer fused I0 but is impervious to either the coarse abrasive alumina. The same bond was used throughout. particles I_ I of the bonded body 'I or the ñne abra The mixture for the bottom layerwas composedr ` ¿E sive particles I2 of the resin bonded bodyV 8. of 26% allyl resin monomer (suchas that known The composite sharpening stone shown in Fig'- V` and sold by the Columbia Chemicals Division of Pittsburgh Plate Glass Co. as CR-39 resin mono ure 1 can be formedin the usual type of mold by partially ?illingthe mold with the ñrst pourable, mer) and 74%V 320 mesh silicon carbide and con liquid resin mixture, inserting the porous sheet taining dissolved iny the monomer benzoyl per material on top of the mold contents by hand, 19 oxide catalyst to the extent of 3% of the mono and ñlling the balance of the mold with the sec mer. This liquid mixture was poured into a=rec-` Vond desired mixture. However,4 it is desirable to ' tangular mold such as that shown in Figure 2. hold the porous diaphragm tightly in position in A sheet of _very porous ñlter paper was then laid order to prevent wrinkling or dislocation of the upon the freshly poured mix. A second casting- sheetmaterial during the pouring of the second 76 mixture was poured onto the filter paper to fill 2,404,192 5 6 the mold. This second casting mixture consisted characteristic abrasive material of each abrading body of the article being separated from the abra sive material c-f the adjoining'abrading body by of 30%' of allyl resin monomer known as CR-39 monomer, 70% very fine fused alumina, polishing Ipowder having a particle size of 600 mesh and nner and 3% benzoyl peroxide based on the monomer. The mold contents were allowed to solidify after which the cast article was removed from the mold and the resin bond cured at 150° F, for 18 hours, then raised 15 degrees per hour for two hours, 10 degrees per hour for two hours, and finally held one hour at 200° F. The cured hone was surfaced on a rotating metal lapping a thin layer of sheet material permeable to the resin bonds but impervious to the abrasive ma» terials of said article. . 2. v.A resin bonded composite abrasive article having at least two dissimilar abrading bodies integrally united by means of a resin bond com-A mon to the constituent bodies thereof, the char acteristic abrasive material of each labrading body of the article being separated from the disc charged with abrasive andwater, The fin abrasive material of the adjoining abrading body ished article was extremely uniform and of high density with a sharp line of demarcation between by a thin layer of sheet material permeable to the resin bond but impervious to the abrasive ma ,the different bonded abrasive bodies thereof. The resin bond thoroughly penetrated through and hardened in the ñlter paper so that there was no sign of delamination or weakness in the terials of said article. ' 3. A resin bonded abrasive article comprising a surface portion of resin bonded abrasive ma terial integrally united to a resinous body portion line of union between the different bonded parts through an intercalary fibrous sheet material im of the article. pervious to the abrasive particles of said surface The bonds which may be >used to make cast portion but permeated by the resin bond. articles accordingto the practices of the present 4. A resin bonded abrasive article comprising invention include those resins produced from un a body of resin bonded abrasive material integral saturated monomers by addition polymerization. 25 ly united to a non-abrasive resinous body through 'I‘ypical monomers are the vinyl, acrylic and allyl an intercalary fibrous shëet material inpervious monomers, such as diallyl phthalate, diallyl to the abrasive particles of the abrasive body but maleate, diallyl fumarate, methyl-methacrylate, permeated by the resin bond of the article. vinyl acetate, styrene, diallyl diethylene glycol 5. A method of making bonded abrasive articles carbonate, and the like. Mixtures of monomers . which comprises preparing amixture comprising to produce copolymers and cross linked resins may a liquid resin and an abrasive filler, pouring said also be used. We may also’use solutions -of re~ mixture into a suitable mold, placing a thin sheet active resins in monomers such as a solution of of ñbrous material permeable to the liquid resin an unsaturated alkyd ofthe glycol~maleic anhy but impervious to the abrasive filler of the afore dride type in diallyl phthalate or styrene mono- i said mixture over ethe top surface of the mixture mer. It is also possible to use certain initial con contained in said mold, preparing a second mix densation polymers in liquid form, such as heat ture comprising a liquid resin and an abrasive hardenable, liquid urea or phenolic casting resins. filler differing from the filler of the ñrst mixture, In practicing the invention any of the abrasive pouring the second mixture into the aforesaid materials in common use may be employed such 40 mold on top of said sheet material, allowing the as silicon carbide, diamonds, boron carbide, fused mold contents to set and removing them from aluminum oxide, nint, corundum,`emery, rouge, the mold. and similar substances. The size of the abrasive 6. A method of making bonded abrasive articles particles may vary from the finest polishing or which comprises preparing a mixture comprising buiflng powder to the coarser grit sizes used in 45 a casting resin and an abrasive filler, pouring grinding. When composite abrasive articles are said mixture into a suitable mold, placing a thin being formed wherein one of the resin bonded sheet of porous material permeable to the casting bodies constituting the entire article is non resin but impervious to the abrasive filler of the abrasive in character any organic or inorganic aforesaid mixture over the top surface of the mix non-abrasive fillersA may be incorporated in the 50 ture contained in said mold, preparing a second resin bond thereof, such as carbon black, clays, mixture comprising a casting resin and an abra wood flours, mineral fillers and the like. sive filler diifering from the filler of the first The present invention is very adaptable to mixture, pouring the second mixture into the making composite abrasive articles which employ aforesaid mold on top of said sheet material, a relatively finely divided abrasive material and 55 allowing the mold contents to set and removing dense bond in one or more of the sections mak them from the mold. ing up the article, such as the combination hone 7. A method of making bonded abrasive articles previously illustrated. The shape of the sec which comprises preparing a mixture comprising l tions making up the article may vary and may a liquid resin and an abrasive filler, pouring said consist of cylinders, rods, sections of a circle and mixture into a suitable mold, placing a thin sheet other shapes as well as layers. Other composite of fibrous material permeable to the liquid resin articles which can be made include mounted hon but impervious to the abrasive ñller of the afore ing wheels, diamond wheels, discs for lapping said mixture over the top surface of the mixture machines, die honing sticks, polishing discs, contained in said mold, preparing a second mix thread grinding wheels, and so forth. ture comprising a liquid resin and a non-abra 65 Having described and set forth the invention sive ñller, pouring the second mixture into the in detail, the scope of the invention is not to be aforesaid mold on top of said sheet material, confined other than by the appended claims. allowing -the mold contents to set and removing We claim: them from the mold. 1. A resin bonded composite abrasive article 70 having at least ftwo dissimilar abrading bodies KERNELL G. RIES. Áintegrally united by means of compatible resin NORMAN P. ROBIE. bonds of the lconstituent abrasive bodies, the PHYLLIS VON DOENHOFF.