US1723982A - Liquid core binder - Google Patents

Description

Patented Aug. 6, 1929.

UNITED STATES PATENT OFFICE.

WILLIAM R. IPATE AND JOSEPH A. GITZEN, OF MILWAUKEE, WISCONSIN, ASSIGNORS TO' LINDSAY-MCMILLAN CO5 OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

LIQUID CORE BINDER.

No Drawing.

are powdered rosin and linseed oil.

The rosin produces what is called a rosin or soft "core and the linseed oil produces what is called an oil or hard core. 7

The core 'is molded from the sand. and

binder mixed together and then it is heated or baked.

The powdered rosin becomes unified and distributed in the sand While the coreis after the grated by the heat from the molten metal.

Powdered rosin, though constituting a binder forcore sand which willbecome plastic when heated to the temperatures involved in core baking and in the casting of metal,

has certain decided disadvantages. For ex-' ample, rosin is very sticky and hard to main-' tam in a pulverized formp Consequently, particularly if the room 1s hot, the pulverized rosin will form into lumps which when mixed with sand by the'core maker produces a nonhon1ogeneous mixture, resulting 111 pockets when the core is baked or when the core is subjected tothe action of themolten metal in a mold lVhenthese pockets appear on the exterior of the core, the result 1s a rough casting. Another disadvantage of the useof powdered rosin as a binder in-a core is that the core does not presenttha strength or toughness required in many v t f ter,1c'ombined in such proportions that the The present invention has as its object .to

operations.

. casting.

()l'JJGCt oi: the present invention is to provide Application filed April 11, 1927. Serial No. 182,998.

provide a liquid corebinder which will be solidified by 'theiheat in baking the core and which will be softened and disintegrated bv the heat of the molten metal. "I

Another object is to provide a liquid core binder which may be readily and economically manufactured. a

Another object istoprovide a liquid core binder which Will readily intermingle with the sand and which Will not cause the core to adhere to the mold in Which it is formed.

Another object is to' provide a core binder which is convenient in use, which may be readily and u'niformly mixed with the core sand, which willhold together the particles of the core sand with sufficient tenacity to permit the cores to be handled, and which will permit the necessary disintegration of the core after the casting operation is completed.

Another object is to provide a liquid core binder which will become plastic under the temperatures encountered in the casting of metal, whereby shrinkage or other stresses set up during the cooling operation of the casting will not result inthe production of destructive stresses to produce cracks in the Expressed in other language, an

a core binder which will produce a core which is 1 lastic under the temperatures encountered in metal casting operations, whereby the core will give, or yield, as shrinkage occurs in the cooling of the cast metal.

Another object is to provioe an improved core'having the advantages of plasticity and toughness above referred to.

According tothis invention as it has been employed in practice, the liquid core binder comprises resin or other suitable soluble binding matter, petroleum oil or distillate or other volatile solvent, and linseed oil'or other suitable strengthening or' drying matbinding matterremains in solution in' the solvent under normal temperature and the rosin maintains its fumlamental characteristics and constitutes the basic binder.

The liquid core binder provided by this invention has many advantageous characteristics, among which are the rosin is in solution and will readily and uniformly intermingle with the sand, it will be soliditied by the heat in baking the core to bind the sand together and hold the core in shape, and it will become plastic and then disintegra e under the heat from the molten metal.

The invention will he further understood and explained from the binder which is set forth in the following composition:

Rosin 40% Light petroleum oil 28 Beaum gravity 10% P e t r 0 l e u m distillate 40 mi ht Beaiun gravity 44% Raw linseed oil 5% Pine oil 1% The rosin constitutes the basic binder and it is in solution .in the light petroleum oil and the petroleum distillate which are a volatile solvent therefor.

The linseed oil gives the rosin increased strength and tenacity (that is cohesion or toughness) and lessens the rosin required to bind the sand together.

'hen 40% rosin and 5% linseed oil are present, the binder will have substantially the same strength as 60% rosin alone.

The linseed oil which is employed is insufiieient in amount to impair the rosin or overcome its characteristics.

Vhen even about 10% linseed oil is present the rosin will still be the basic binder and maintain its characteristics over the linseed oil.

The pine oil is a ready rosin solvent and promotes maintaining the rosin in solution. The linseed oil, in addition to having drying characteristics to increase the strength and tenacity of the binder, constitutes a solvent. for rosin. Therefore, all of the liquids employed with the rosin act cumulatively to hold the rosin in solution.

The solvent retains the rosin in permanent solution under ordinary temperature.

When the core in which the binder is employed is heated and baked, the solvent is volatilized and eliminated and the rosin and the linseed oil therein are solidified to bind the sand together. The distillate distills'out with the water in the core sand at the core baking temperatures.

The provision of the petroleum solvents having different boiling'f'points produces the following'advant'ag'es":The light petroleum oil (which for examplemay be paraffin oil) permits the melting of the rosin without decomposition thereof. Later on in the baking of the core, said light petroleum oil protects the rosin, so that if too high a temperature should be used. or baking should be com tinned for too long a time, the rosin is protected against decomposition. The lighter distillate has the advantage that the mixture is rendered sufliciently fluid to distribute itself unitormly throughout the core sand.

In order to facilitate making the binder and to lessen the volatilization thereof under normal.temperature, the light petroleum oil and the petroleum distillate are employed as the solvent.

.The-light petroleum oil is less volatile than the petroleum distillate, and the petroleum distillate is more fluid and less adhesive than the light petroleum oil.

According to the ordinary process employed to make the binder, the rosin is dissolved under heat which is suliieient to melt the rosin.

\Vhen the solution thus obtained is reduced to substantially normal temperature, the petroleum distillate is introduced to make it more fluid and to lessen its adhesiveness.

The linseed oil may be introduced either while the solution is heated or after it is cooled.

The pine oil is introduced after the solution has been cooled.

According to another process for making the hinder, the rosin while it is in a heated liquid state in being obtained from its original source is dissolved in the light petroleum oil and then the other ingredients are incorporated in the way which has been set forth.

An important feature of the present in-,

vention is that it provides the advantages of rosin in that the core will become plastic under heat (followed by disintegration of the core) as the temperature of the core is raised to a predetermined value. The present invention has the advantage over rosin that, being a liquid, distribution throughout the core sand is more readily and uniformly accomplished. The present invention has the further advantage over dry rosin that the flying powder does not have to be contended with.

The present invention has decided advantages over 011 cores (that is, cores comprising sand and core oil or comprising sand and linseed oil,) in that it provides plasticity, whereas oil cores do not have plasticity. An oihcore will not soften under heat,

went invention ing oil core will, in many instances, produce breakage of the casting. Oilcores, however,

by reason of their cheapness, have a field of usefulnessin many types of castings Where breakage of the cast ngs is not likely to occur, as for examp'lewuh gray iron castings,

which have a relatively low shrinkage modulus, or in castings so designed that the shrinkage is low. The present invention lies in a field distinct from oll cores and con stitutes an improvement over rosin cores.

The present invention is particularly ap plicable to the making of castings m which the core shouldchange its shape under the shrinkage ofthe casting. Cast ngs are p raetic-ally always pro'vided with apertures which permit the oozingof the plastic core therethrough. Cores manufactured accord-- the liquid core-binder according. to the-presplasticity stage.

iii-"many instances, for the reason that the fluidcomprising the present invention'jpen mcates the core sand muchmore readily than does pulverized rosin and is decidedly. more eflicientas a binder'than is pulverized ros n.

Therefore, less of the liquid employing the principles of'the present invention is required .(by weight) for-a unit amount of sand than is required of rosin. q i

Added to this advantage is the advantage that no lumps of rosin will collect on the surface of the core, which lumps will fall out either during the core baking operation or thereafter; leaving a rough surface which promotes chafing when the cores contact withone another in storage. Expressed in other language, cores made with liquid employing the principles of the present inven tion are smoother than rosin cores, and consequently will not wear away and crumble A further ad vantage is the smoother casting 'resultlng as readily as rosin cores.

from the practiceof the present invention.

Still another advantage of the presentin-" vention is the reduction ot labor cost from.

the cost involved in the working of rosin,

inasmuch as the n'lani-pulation otthe core hinder employing the principlcslof the present invention doesnot have the unpleasant features of flying powdered ros n. 1

Of course, the composition which has been set fOItl1' l1C!0il1 to illustrate the invention and further the process of making the same may be modified in various ways.

' The invention claimed is as follows:

will disintegrate after the baking temperatures, and

1. A liquid core binder comprising rosin about forty percent a volatile solvent about fifty-five percent and linseed oil about five percent (5%) by weight.

2. A liquid core. binder comprising rosin about forty percent (40%), petroleum oil about ten percent (10%), petroleum distillate about forty-live percent (45%) and linseed oil about five percent (5%) by Weight.

3. A liquid core binder comprising rosin about forty percent (40%), light petroleum oil about ten percent (10%), petroleum distillate about forty-four percent (44%), linseed oil about five percent (5%) and pine oil about one percent (1%) by weight.

.4. A core binderadapted for use with core sand in the manufacture of baked cores col-uprising a liquid including resin in a suliicient amount to constitute the essence of metal casting temperatures, and a solvent HOH VOlELiZIlG: under normal temperatures,

' said rosin being in solution in; said solvent, ing to the present lnvention oremploying said solvent including petroleum derivatives and linseed'oil.

I 5. A core binder adapted for use with core sand in the manufacture of baked cores comprising a liquid including resin in a suiticicnt amount to constitute the essence of said co re binder and insure plasticity. under metal .CRStInQ temperatures,. and a solvent nonvolahleunder normal- .temperatures, said rosin being in solution in said solvent, said solvent includingpetroleum derivatives and an oil having drying characteristics.

6.: A core resulting from the application of core baking temperature to a mixture of core sand and a binder, which binder is a liquid under normal 'tei'nperatures and includes resin in a suflicient-quantity to bind the par- 'ticlesof said core into a mass plastic under metal casting temperatures, said rosin being dissolved in a liquid including petroleum. derivatives non-volatile at normal temperatures and linseed oil. i

7. A. core resulting from the application of core baking temperature to a mixture of core sand and a bi nder which binder is a liquid under normaltemperaturesand ineludes rosin in a suflicient quantity to bind the partieles of said core into a mass'plastic under metal casting temperatures said rosin being dissolved in a liquid including petroleum derivatives non-volatile under norvmal f tem eraturesjand an oil having drying characteristics.

8. A core resulting from the application of heat-"to a mixture of core sand and a binder, w'hich hinder containssuiiicient' rosin to bind the particlesot said coresand into a mass plasticunder meta-l casting temperatures, a solvent for said rosin non-volatile atnormal temperatures but volatile at core an oil having drying characteristics, said oil being in sufli- 1 inous substance dissolved in a mixture of petroleum solvents having difierent boiling points and non-volatile under normal temperatures and an oil having drying characteristics, said petroleum solvents and said oil having cumulative solvent actions on said resinous substance, saidoil being insuflicient in quantity to harden said binder beyond a plastic stage at metal casting temperatures.

, In witness whereof we have hereunto subscribed our names.

\VILLIAM R. PATE. JOSEPH A. GITZEN.