Патент USA US2369689код для вставки
2,369,689 UNITED STATES PATENT OFFICE Patented Feb. 20, 1945 2,369,689 _ m w ,9, ABBASIVE ARTICLES AND METHODS or MANUFACTURING THE SAME Norman P.‘ Robie, Lewiston, and Osborne L. iii... W ,5... 3..., g ; iii... t.) u a .-... a N. Y., assignors to The Mahlman, Kenmore, Company, Niagara Falls, N. Y., a Carborundum corporation of Delaware No Drawing. Application November 6, 1941, Serial No. 418,010 12 Claims. (on. 51—--298) ' su?lcient viscosity to be satisfactory in the pro duction of both molded and coated articles and This invention relates to abrasive articles and methods of manufacturing the same. More speci?cally, the invention is concerned with the which will heat-harden to a substantially in fusible condition without the generation of gaseous icy-products. A further object of the invention will be apparent from the consideration of the ltollowing speci?cation. production of abrasive products in which the bond comprises the resinous reaction product. of an unsaturated monomeric material with the unsaturated esteri?cation. product or an alcohol and a polybasic acid. , _ I We have discovered that the objects set forth above can be accomplished by employing, as a ' ‘Although the invention is adapted to the pro binder for the abrasive grains, the reaction duction of various types of abrasives, including 10 product of a mixture of unsaturated monomeric both the coated abrasives as represented by the materials with unsaturated esteri?cation prod conventional “sandpaper" and the bonded ucts of alcohols with polybasic organic acids. articles such as abrasive wheels or stones, it is The unsaturation of the esters, which are com particularly well adapted for production of very monly employed in the form of polyesters, can be provided by the use of either an unsaturated alcohol or an unsaturated polybasic acid or both. The polybasic acids are characterized by the dense bonded articles which are substantially free from pore space. Such articles are of parti cular utility in the ?eld of ?ne ?nishing and in cases where it is desired that the abrasive article presence Oif shall maintain its grinding face while grinding two or more carboiwl groups (COOH), the hydrogen of which combines with as, for example, in the ?eld or thread grinding. 20 the hydroxyl group (OH) , which is characteristic A very large part or the resin bonded abrasive of alcohols, to form water and join the remain articles is made with a phenol aldehyde con ing part of alcohol and acid groups into an ester. densation product as the bond. Such products When a polybasic acid containing two carboxyl have a wide utility, but the phenol aldehyde groups, reacts with an alcohol containing two resins are not well suited for the production 25 hydroxyl groups, the reaction product is of the of extremely dense wheels because during the nature of a. chain in which one carboxyl of the curing or heat-hardening of the resin gaseous acid joins to one hydroxyl of an alcohol molecule products are evolved, and unless the abrasive the other carboxyl group of the acid being re article has-a certain minimum porosity to allow acted'with a different alcohol molecule. Such for the escape of these gases the article swells 30 products are herein referred to as “polyesters” and bloats and is therefore unsatisfactory. because they comprise molecules made up from Attempts have been made to make very dense a plurality of individual alcohol and acid mole articles by the polymerization of monomeric ma cules joined together as distinguished from the terials such as vinyl esters or the esters of acrylic acid. Such polymerization does not involve the evolution of gaseous lay-products and is there fore adapted to the production of dense, non 35 porous bodies. However, this process is unsat isfactory for two principal reasons. In the ?rst ordinary esters, which constitute individual and single ester molecules. The polyesters formed in the primary stages of our invention are ordinarily very viscous liquids. Since the water formed by esteri?ca tion is produced during this primary stage re place, the monomeric materials are thin liquids 40 action we provide a. part of the bond in the and it is di?icult to get a stable and homogeneous partially reacted condition such that no gaseous suspension of the abrasive particles in such or volatile by-products are produced by further liquids. In the second place, the polymerization esteri?cation. Consequently when the ?nal or products are permanently thermoplastic as dis heat-hardening ‘process is carried out the re tinguished from the heat-hardened iniusible type action is not accompanied by the evolution of obtained by the reaction of phenol with alde volatile materials because the ?nal step is a mere hydes, and when such articles are used for dry grinding the bond scritens and both smears the work with the bond and picks up the detritus formed by grinding to cause the articles to be come loaded. combination at the double bond, such as takes vention to provide abrasive articles in which the bond is infusible and which have substantially no porosity. Another object of the invention is the provision of abrasive articles and method oi'manufacturing such articles which are dense, accordance with our invention is brought about by reason of the fact that when the unsaturated polyesters oi polybasic acids are mixed with It is accordingly an object of the present in- ' place in the ordinary linear polymerization of such materials as vinyl acetate or the acrylic acid compounds, the product or which is herein referred to as an “additive reaction product.” The iniusibility oi the products iormed in polymerizable monomeric materials the chains formed during the polymerization are joined by hard and substantially free from porosity. An the other component of the reaction mixture other obiect-of the invention is the provision out and the two or three dimensional molecule thus 60. a bond for abrasive articles which will have '2 aseassa ' formed is more‘ heat-resistant, whereas the chain length we may obtain the necessary straight chain molecules of such materials as amount of unsaturation by using an unsaturated polyvinyl acetate are softenable by heat. The monobasic acid to limit the chain length. For process which we have described for the fema instance. a short chain polyester with three un tion of polyesters requires the use of both poly saturations may consist of one mole of fumaric hydric alcohols and polybasic acids. As an al acid, two moles of glycol and two moles of metha ternative we may employ unsaturated mono crylic acid. The fumaric acid will be in the hydric alcohols with unsaturated polybasic acids center with a mole of glycol on each ,side and the to form esters which polymerize by the conven methacrylic acid on each end. tional additionreaction brought about by the The invention will now be further described with reference to specific examples. It is to be joiningi of the monomeric esters at some of the double bonds of the esters. These partially poly understoodv that these examples merely illustrate merized esters still contain suiiicient unsatura tion to be capable of interaction with the poly merizable monomeric materials to form the in certain embodiments of the invention which is capable of'numerous variations and is to be limited only by the appended claims. Example I.--We have found the new type of bond to be suitable for uniform, very hard, dense fine grit wheels used for razor honing. The fol lfusible binders characteristic of our invention. We have found that polyesters formed by the reaction of diethylene glycol, which is a- dihy-' dric alcohol, with maleic or fumaric acids are lowing example illustrates this type of wheel. well adapted for use in the forming of our bind 20 The polyester of diethylene glycol fumarate ers where the polyesters are formed from poly was prepared by heating 1044 gms. furnaric acid hydric alcohols. For the production of esters with 990 gms. of diethylene glycol for seven with a monohydric unsaturated alcohol we have hours on an oil bath reaching 200° C. in 21/4 used allyl alcohol to form dlallyl maleate or hours and maintaining that temperature for the fumarate. For the polymerizable monomeric 25 remaining time. Carbon dioxide was bubbled materials we have used vinyl compounds such as through the ?ask to agitate the mixture and vinyl acetate and styrene and found them to be prevent oxidation. A resinous balsam resulted. well suited to our purposes. Instead of these Vinyl acetate and styrene monomers were sepa particular materials we can employ other poly rately distilled to remove the inhibitor and the hydric alcohols such as ethylene glycol; tri 30 reaction mixture for forming the bond was then methylene glycol; tri and tetraethylene glycol; made in the following proportions: glycerol; propylene glycol, monoethylin, and un ’Grams saturated glycols such as obtained by hydrolysis Diethylene glycol fumarate polyester _____ -_ 514 of butadiene dibromide, and other polybasic un Inhibitor free vinyl acetate monomer _____ __ 163 saturated acids such as aconitic, citraconic, itaconic, vinylmalonic, the terpene-maleic an hydride’ adduct known as "Petrex” and the like. ' Inhibitor free styrene monomer _________ __ 88 Benzoyl peroxide _______________________ __ 1.9 Other unsaturated monohydric alcohols which The polyester was warmed slightly anddissolved in the vinyl acetate, the benzoyl peroxide was alcohol, methyl vinyl carbinol, divinyl carbinol, 41 dissolved in styrene, and the two solutions were 3-chloro-2-butanol-1, butadiene-1, 2-01-4, crotyl mixed. The above bond mixture hardens at alcohol and the like. 130° F. to a very hard light amber colored glass Instead of the vinyl compounds vinyl acetate like resin which, when heated will char without and styrene speci?cally referred to above, we may fusion. employ, as the unsaturated monomeric compound 45 The liquid resin mixture was uniformly ‘mixed » various monomers, having solvent action on the with 750 gms. of very ?ne calcined alumina from esters and polyesters, such as vinyl chloracetate the Bayer process and forced thru a fine screen and other vinyl-esters,, vinyl ketones, vinyl to insure uniformity. The creamy syrup was ethers, esters of acrylic and methacrylic acid, then poured into cylindrical molds to give cast~ acrolein, acrylonitrile and the like. With these 51 ings 5" long x 3"_in diameter. The cast mix monomers which are soluble may be blended un ture prior to hardening was subjected to a me. saturated monomers which are without a sol chanical vibration to cause all air bubbles to rise vent action or are normally gaseous such as to the top where they can be removed. The casting was hardened at 130° F. for 48 hours. butadiene, vinyl chloride, coumarone. indene. isobutylene, chloroprene, vinyl acetylene and the 55 When cured it had shrunk awayv from the mold facilitating easy removal for ?nal surfacing and like. when gaseous monomers are used the insertion of the arbor. The product was a high hardening may be performed under pressure. ly satisfactory razor blade honing wheel. Since we have found it is only necessary to Example II.—-Hard dense wheels suitable for provide occasional double bonds in the poly esters, we have successfully carried out our in Oi thread grinding were produced from the follow ing composition using the procedure of Ex vention by using a mixture of an unsaturated ample I. polybasic acid with a saturated polybasic acid ‘ such as succinic acid, to form the polyesters. In Grams 180 grit fused alumina _________ -_~. _______ -- 440 such cases the degree of unsaturation depends upon the relative proportion of the unsaturated 05 400 grit fused alumina _________________ __'_ 100 we may use include propargyl alcohol, methallyl acid to the saturated acid, and by the selection Diethylene glycol fumarate polyester.v ____ -- 140 of different kinds of acids and di?erent propor~ portions of unsaturated and saturated acids we Vinyl acetate monomer ___________ -..-.... ..- 45 Styrene monomer ______________ _.- ______ -_ 25 Benzoyl peroxide ____ -.. _____ __; _________ _- 0.5 are able to produce binders having quite differ 70 ‘ ent physical characteristics. The dense glass-like nature of this bond aids the grinding wheel to retain the shape of the grind ing surface during the thread grinding operation. Example IIL-The polyesters may be diluted‘ length of the polyester. with polyesters of short 75 with su?icient vinyl resin monomer to give a The polyesters we use may be further modi ?ed by using a monobasic acid with a polybasic acid. The monobasic acid limits the chain. 3 ~ aseaaee An abrasive wheel employing this material was _ made of the following compositions: 70 parts of this Petrex modi?ed polyester was sticky liquid adhesive very suitable for adhering abrasive grain to a backing. . . , 100 gms. diethylene glycol-fumarate polyester mixed with: '10 parts styrene monomer 0.4 parts benzoyl peroxide 150 parts ?nely pulverized calcined alumina from made in accordance with Example I was mixed with 18 cc. diallyl fumarate and 32v cc. vinyl acetate monomer containing 0.2 gm. benzoyl peroxide. A sticky viscous liquid resulted. This was coated onto heavy 130# manila paper and the Bayer process. ) 30 grit fused alumina was spread uniformly over This mix was run through a ?ne screen and cast the adhesive layer. Another light adhesive layer 10 into a razor honing wheel. . The wheel was then was spread over the grain. The coated paper hardened at 120° F. to produce a uniform solid was then cured at 150° F. for 461/2 hours and then wheel with surfaces free from pores, and suitable at 250° F. for 21/2‘ hours. The resulting cured for honing razor blades. resin held the grain very tenaciously to . the We have described unsaturated polyesters suit 15 paper. able for our invention whose unsaturation is duev to the unsaturated acid used. We may also pro duce our polyesters with an unsaturated alcohol Example IV.—159 parts diethylene glycol was esterl?ed with 174 parts aconitic acid while agitating with a CO: stream by heating to 150°C. such as allyl alcohol or with an unsaturated in one hour, raising the temperature from 150 to glycol such as butenediol and a saturated or an 170° C. in 1/2 hour and holding the temperature 20 unsaturated acid. ' at 170° C. for 2 hours. The'aconitic acid poly ester became a viscous balsam more quickly than The high strength of our binder may be illus-' trated by the following data obtained by casting the fumarate polyester. The aconitic acid ester also dissolves vinyl acetate more slowly than, the fumarate polyester. 25 ~ 6" x 1" square test bars of ?lled and un?lled resin and determining its modulus of rupture. A resinous solution was prepared by adding 0.2 Resin composition part benzoyl- peroxide dissolved in 25 parts vinyl acetate, to 75 parts of the aconitic acid polyester. This resinous solution has sufficient acidity due to unesteri?ed carboxyl groups in the polyester 30 to be easily emulsi?ed by an aqueous solution of sodium hydroxide. This emulsion was coated . No. 1 No. 2 Diethylene iumei'ate polyester. _ _.parts._ Vinyl acetate monomer ..... _. . _ .do____ 109 35 109 36 Styrene monomer ........... ._ _do____ l9 l9 Benzoyl peroxide ............. __ _..do.._. 0. 4 0. 5 200 mesh and ?ner fused quartz ............. _.do_.__ ...... ._ 150 Modulus of rupture ............................... __ i3, 160 6. 320 onto strong manila paper and the coated paper was covered with fused alumina abrasive. The The compositions were hardened 64 hours at 125° emulsion was hardened by heating for 40 hours 35 F. and then 7 hours at 200° F. The un?lled test bar was hard and glassy bending slightly in the at 125° F. and 48 hours‘at' 200° F. A ?exible testing machine before shattering‘ into many strong adhesive resulted holding the abrasive . 'pieces. The quartz ?lled bar resembled a piece Example V.-A hardened molded abrasive of marble with a hard metallic ring. It is obvious that the binders and adhesives bed may be modi?ed by the usual methods. tenaciously to the backing. article bonded by a phenolic resin was made 40 much more water resistant by ?lling the pores _ with the following composition: Diethylene glycol fumarate polyester as per Parts ,5. ExampleI __________________________ ..- 175.5 Vinyl acetate monomer ________________ __ 58.5 Styrene monomer _____________________ _. 58.5 Benzoyl peroxide ______________________ __ 0.5 The article ?lled and submerged in the composi tion was warmed slightly above roomv tempera ture until the liquid formed a soft gel. The ex cess soft gel was then sliced off the abrasive article and the filled article further baked at 130° F. until the gel hardened to a hard glass like resin ?lling the pores of the abrasive article. Such a filled abrasive article is adapted for use in warm water like a pulp wheel because of its resistance to water. Example V_I.—-The solubility of our'polyester toward vinyl monomers may be modi?ed by the addition of a terpene-maleic anhydride adduct known as “Petrex.” This modi?cation also re duces the tendency of the resin to crack when curing quickly. A "Petrex” modi?ed polyester was produced as follows: Parts Diethylene glycol ______________________ .._ 80 Fumaric acid ______ ..__ __________________ _- 43.5 Petrex acid _____________________ __'_ ____ -_ 80 This mixture was heated, while bubbling nitrogen into the mix, taking 21/2 hours to reach 195°- C. and maintaining this temperature for two hours. A light amber, sticky, viscous balsam-like resin resulted. ' descri Polymerization may be carried out under differ ent conditions to modify the resin properties. Natural and synthetic resins and drying oils, may be blended with either the esters, polyesters or monomeric hardening agent. For example saturated soluble, uncured alkyd resins may be blended with our unsaturated polyesters. Poly mers may be dissolved in the monomeric mate rial before blending with the polyester and hardening. Catalysts, organic and inorganic ?llers, dyestuffs,‘ plasticizers and anticatalysts may also be employed. We have described our invention with selected characteristic examples by way of illustration. It is obvious that modi?cations of the foregoing examples are possible. These modi?cations are apparent from the foregoing description and the _ invention is to be limited only by the accompany ing claims. We claim: 1. An abrasive article comprising abrasive grains and a hardened binder comprising the ad ditive reaction product of a substantially neutral ' unsaturated monomeric material and an unsat urated esteri?cation product of an aliphatic alco hol and a polybasic acid. 2. An abrasive article comprising abrasive 70 grains and a hardened binder comprising the additive reaction product of a substantially neu tral unsaturated monomeric material with a poly ester of an aliphatic polyhydric alcohol and an unsaturated polybaslc acid." 3. An abrasive article comprising abrasive 4 . a,sea,eaa grains and a hardened binder comprising the additive reaction product 01' a substantially neu tral unsaturated monomeric material with a poly ester of an unsaturated aliphatic alcohol and a polybasic acid. ' g 4. An abrasive article comprising abrasive grains and a binder comprising the additive reac- ’ tion product or a vinyl compound and an unsat- ,_ - v _ 10. The method of making abrasive products which comprises preparing an unsaturated poly ester by reacting an aliphatic alcohol with a poly ‘basic acid, mixing the ester with a substantially neutral unsaturated monomeric material reactive therewith and with abrasive grains, and heating the article to solidify the binder by. bringing about an additive reaction between the monomeric ma urated esteri?cation product of an aliphatic alco ' terial and the polyester to cross-link polyester hol and a polybasic acid. 10 molecules. 5. An abrasive article comprising abrasive 1 11. The method of making a dense abrasive ar grains and a hardened binder comprising the ad-_ ticle which is substantially free from porosity ditive reaction product or diethylene glycol tu which comprises commingling an unsaturated marate polyester and a vinyl compound. - 6. An abrasive article comprising abrasive 15 polyester, a substantially neutral unsaturated monomeric material reactive with the said poly grains and a, ‘hardened binder comprising the ester and abrasive grains, shaping an article from ' additive reaction product oi’ a substantially neu the mixture thus prepared,v and heating the'ar tral unsaturated monomeric "material and an ester of an unsaturated aliphatic monohydric ‘alcohol and an unsaturated polybasic acid‘. ticle to solidify the binder to an infusible state by bringing about an additive reaction between . monomeric material and the polyester to 7. Ah abrasive article comprising abrasive 20 the cross-link polyester molecules. grains and a hardened binder comprising‘ the ' 12. The method of making a coated abrasive additive reaction product of diallyl iumarate and article which comprises preparing a liquid adhe a vinyl compound. ~ sive comprising an unsaturated esteri?cation 8. An abrasive article comprising bonded abra product of an aliphatic alcohol with a polybasic sive grains molded and hardened to shape and acid and a substantially neutral unsaturated, impregnated with an additional hardened binder monomeric material reactive with the said ester comprising the additive reaction product or a i?cation product, coating a backing with such ~~ substantially neutral unsaturated monomeric ma adhesive and abrasive grains, and heating the terial with an unsaturated esteri?cation product 30 article to harden the binder by bringingabout an of an aliphatic alcohol and a polybasic acid. additive reaction between the monomeric material 9. An abrasive article comprising abrasive and the esteri?cation product to cross-link the grains and a hardened binder comprising the additive reaction product of a substantially neu tral unsaturated monomeric material with an un saturated esterl?cation product 01' an aliphatic polyhydric alcohol and-‘both a monobasic and a polybasic acid. 7 . esteri?cation product molecules. NORMAN P.‘ RDBIE. - OSBORNE L. MAHLMAN.