US2270770A - Foundry mold wash - Google Patents

Description

- ing foundry cores and about to be described, or will be Patented 1515-20, 1942 UNITED STAT FOUNDRY MOLD WASH Philip A. Ray, Wilmington, cules Powder. Company,

corporation of Delaware Wilmington, DeL, a

DeL, assignor to Her- No Drawing." Application November 10, 1939, I

Serial No. 3 Claims. ,(Cl. 22-489) This invention relates to metal foundinggand more particularly to a wash for coating, or facmolds; or the like.

An object of the invention is to provide a core or mold wash which can be economically and easily prepared.

Another object is to provide a core or mold wash which does not require expensive emulsifying agents, drying oils, or adhesives.

Another object is to provide a core or mold wash having a dispersion of refractory material therein, which can stand for long periods without settling out of the refractory material.

' Another object is to provide-a core or mold wash which can be readily appliedby sprayingf, l5

swabbing or dipping and can be subsequently dried in a convenient and expeditious manner.

Another object is to provide a core or mold wash which, when applied, forms a smooth facing of sufficient strength to resist the erosive action of molten metal during the casting process.

Another object is toprovide a core or mold facing which prevents the -metal from fusing with the sand or founding forms and thus saves time and'labor in the cleaning operations.

Another object is to provide a core or mold facing which will produce castings having a smooth surface, whereby expensive grinding or chipping operations are eliminated.

A further object is to provide foundry structures such as cores or molds having an improved facing.

Other and further objects will be obvious upon an understanding of the illustrative embodiment the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of theinvention in practice.

These objects are generally accomplished by preparing a wash or dispersion comprising refractory material, a fluid suspending medium, a suspending agent, if desired, and an adhesive or binder adapted to cause=the refractoryparticles to adhere to each other and form a smooth film or coating when applied on the surface of sand founding cores or molds.

Suitable refractory materials which may be used are finely divided graphite, plumbago (native carbon in flake form), silica flour, soapstone, talc, zirconium dioxide,or the like. Preferably, plumbago or silica flour are employed and in amounts by weight.

' able to stabilize indicated in between about 25 and about parts which maybe to about parts by desired consistency of the wash. inflammable fluid may medium. Such a,fluid position comprising approximately weight ethyl alcohol, 5 parts by weight ethyl acetate and l aviation grade gasoline. This" composition may be used in amounts between alcohol, 5 parts part by weight used in amounts between about 25 weight, depending upon the Also, a volatile be used asa suspending 90 parts by by weight methyl about 50 and. about parts by weight.

If a suspending agent isnecessary or desirthe dispersion, bentonite, that is, colloidal clay,:preferably is used in amounts between about .5 and about 5 parts 1y weight.

Ithas been found that a pulverized pine wood resin which is substantially insoluble in petite-'- leum hydrocarbons such as gasoline, has the de sired characteristics of cooperating with the othermaterials of the geneous, stable agglomerates.

resin serves as When dispersion wash to provide a homowhich is free from the wash is dried, this an adhesive orbinder to cause.

therefractory particles to adhere to each other molds or cores. be applied in and form a smooth glaze-like coating on sand The, binder enables the wash to; 7 small quantities and form a film resistant to the ero-.-

sive action of molten .metal and prevents the cellent results.

metal from fusingwiththe'sand of the core or molds. Preferably, between .10 parts by weight of the.

about 1 and about resin" produce ex- The material which is' characterized by the term pine wood resin ay not have substantially insoluble in gasoline herein and in the appended, claims, is the resinous ma which. may be prepared preferably from stump pine The pine wood. been steamed to manner.

remove volatile constituents such as turpentine and pine oil, may be hydrocarbon such as extract then freed of volatile constituents, leaving a residue consisting of a mixture ofwood extracted with a coal tar benzol or toluol, and the resin and the resin used in the present compo-. sitionsn Extraction of this mixture with a petroleum hydrocarbon such 'as, for example, ,gas-

oline, dissolves and removes the rosin. separation f the rosin,

After resinous residue remains which is low in abietic.

acid. Alternatively, carbon extract may be the two layers which the initial coal tar hydro-- treated with furfural, and form separated, in which The fluid suspending medium may be water 55 case the resinous residue is found dissolved in may be an alcohol comhigh in abietic acid, a

the furfural from which it may be obtained by and heating it to about 110 C. An aqueous soevaporation of the f irfural. resinous resilution of parts of casein made soluble by -3 due, used in the composition ofijfthe present inpar-ts ammonium hydroxide in 30 parts of water vention, is characterized by a dark red brown is prepared. An ammonia solution of 6 parts color, cherry-red in solution, and by substantial 5 ammonium hydroxide in 100 parts of water is insolubility in petroleum hydrocarbons, but it added to the molten resin while stirring slowly will vary somewhat in its specific characteristics first and gradually increasing the speed of agisuch as acid number, melting point, exact petation as the emulsion is formed. The casein troleum ether solubility, and content of naphtha solution is then added to complete the emulsifiand toluol insoluble material, depending upon 10 cationhe r l ing emulsion is light brown the details of the extraction processes utilized. n color. ta f fin pa t size. a d nta ns This resin will meet or nearly meet the followabout 40% solids. ing specifications, namely, substantial insolubilample V ity in hydrocarbons Substantially A suitable wash adapted for air or flash drycomplete solubmty m alcohol a methoxy ing, wherein a volatile solvent is employed as the tent from about 3% to about 7.5 (usually from suspending fluid may comprise. about 4% to about 6%) an acid number in the Partsb Wei ht range from about 90 to about 110, anda drop plun bago r silica flour melting pointin the range from about 95 C. to Resin e 2 Volatile soi entui 73 While the proportions of the ingredients may vary, the following formulations are given as ex- Pinewood resin substantiall insoluble in amples of core or mold washes which have been y gasoline.

found to produce excellent results:

' I 25 The resin is the same as that used in the fore- Examples going examples. The volatile solvent employed v may be an alcohol composition comprising 90- g I H In parts ethyl alcohol, 5 parts methyl alcohol, 5

s. parts ethyl acetate, and 1 part aviation grade Farm Pam, Pam by gasoline. The resin and refractory materials weight wei ht weight can bedispersed in the solvent without the use 45 I of a suspending agent, such as bentonite. However, it may be desirable to agitate suchwashes 5 during application in order to keep the refrac- I tory materials suspended in the solvent. Pine wocd resin substantially insolubleingasoliiie. The Wash may be i' to t Surface of In preparing the a compositions illustrated cores or molds or 0 her founding structures by Examples I, II, and III, pulverized resin, the refractory material (pl'umbago or silica flour) and bentonite are mixed together well before 40 pending medium (Examples I, II, III, and IV), the wash may be applied to the cores prior to reiterate. d sc ar es? bait gg or gg a o e cores W' ry the m of, wash. f degmount of gagg gia f i' i ggg ii 3 g: sired, the wash may be applied immediately after 532 32 2 bentogitz by etheswter A sgitable the cores or molds have been baked so that the wetting agent for this purpose is a composition zfi s gi i? of the sand whfle coohng Wm dry comprising about 85 parts pine oil, nine parts oleic acid soda s ap and six parts water, al-

a smooth facing. Also, the wash may be applied after the cores or molds have though other wetting compositions maybe read- 28:2 :11, 2: 2 32 23 33 3 by heatlpg the ily substituted. After thorough wetting of the Where the Volatile composm'on is used as a materials, the wash is made up to desired consistency and is well agitated by a suitable stirring device.

Example IV a mitted to an dry. If deS1Ied, t0 expedite drying,

A suitable wash, wherein the resin is first inflammable alcohol composition, which, upon emulsified, may comprise the following ingrediburning leaves a hard smooth film or protective ents: facing of refractory materials on the surface.

I Parts by weight This may also be applied to green sand molds or Plumbago or silica flour 40 cores and the heat created by the burning s0i- Water 50 vent may be utilized to sufflciently dry the sand. Resin emulsion 10 From the foregoing description, it will be seen In preparing this composition, the resin is that h present Invention provide? s.amp1e emulsified in water by means of casein, soya bean expenswe core or mold .wash is easy to protein, animal glue, or other protective colloid, prepare and can be readfly i only small which has been cut with alkali, such as ammonia or sodium carbonate. Preferably, the proportions of materials used are:

of hot metal and prevent fusing of the sand so Parts by Welghg that the sand willreadily peel from the casting. Resin h cores, molds, or other founding structures gi eg 1-2-5715?) 9 provided with this film produce better castin s er 130 which require a minimum amount of r nd n chipping other machining operations, thereby The emulsion is prepared by melting the resin greatly reducing the founding costs and speeding up production. Another feature of the invention is that the resin may be used in relatively small amounts and that quantities of resin remaining in the sand will not prevent its further use in forms.

It will be understood that the details and examples hereinbefore set forth are illustrative only broadly described and thereby. to protect by Letters and that the invention as claimed is in no way limited What I claim and desire Patent is:

1. A foundry mold and core wash composition essentially comprising a finely-divided refractory material, a finely-divided substantially gasoabout 10 per cent by weight of the insoluble resin derived from pine wood,

2. A foundry mold and core wash composition essentially comprising a finely-divided refractory material, a finely-divided substantially gasolineinsoluble resin derived from pine wood, a suspending agent, and a volatile liquid suspending medium, said refractory material, suspending agent, and suspending medium being present in such relative proportions that the composition is in fluid form, and said resin being present in an amount representing between about 1 and about 10 per cent by weight of the entire composition.

3. A foundry mold and core wash composition comprising between about 25 and about 50 per cent by weight of a finely-divided refractory material, between about 1 and about 10 per cent by weight of a finely-divided substantially gasolineand the remainder consisting of a volatile inflammable liquid suspending medium.

PHILIP A. RAY.

Patent No 2., 270 ,770

CERTIFICATE OF CORRECTIOI.

January 20, 191m PHILIP A} RAY.

It 1 hereby certified that error appears in the printed speclrlcation ofthe above numbered patent requiring correction as follows: Page'l, first column, line 2b., for "or" read -of-; page 2, second columnQIine k2, Ior making read --ba.king--; and line 65, for "sample" read --simple--; 'and that the said Letters Patent should be read with this correct-ion therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 10th day of March, A. 1), 19h2.

7 Henry Van Arsdale, (Seal) Acting Commissioner of Patents.