CA1155997A

CA1155997A - Urethane binder compositions for no bake foundry application utilizing amine polyols

Info

Publication number: CA1155997A
Application number: CA000329489A
Authority: CA
Inventors: Robert J. Schafer
Original assignee: Ashland Oil Inc
Current assignee: Ashland LLC
Priority date: 1978-06-14
Filing date: 1979-06-11
Publication date: 1983-10-25
Also published as: FR2434828B1; AU4773879A; JPS5514192A; BR7903690A; TR20846A; BE876906A; NL7904524A; ZA792736B; PT69765A; MA18469A1; AU517094B2; JPS643586B2; FR2435488A1; MX153925A; AT381876B; IT1121796B; FR2434828A1; IT7923537A0; ES481604A1; AR220945A1

Abstract

ABSTRACT
No Bake foundry cores and molds for casting metals are prepared by using a binder comprising a polyol generally derived from alkoxylating an amine compound and a polyisocyanate. The binder is especially useful for casting non-ferrous metals, for example, the casting of aluminum, magnesium and other light weight metals. The cores and molds produced for casting aluminum and other light weight metals exhibit excellent shakeout while retain-ing other desirable core and mold properties. In addition the binders of this invention would have been observed to have an autocatalytic nature.

Description

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BACKGROUND 0~ THE INVENTION
~ i This ~lvention relates to resinous binder com~ositions which are ad-mixtures of amine-based polyols and polyisocyanates. In another aspect ~h;s invention relates to curable urethane binder compositions which are useful ~or binding particlaate solids. In particular the illvention relates to binders, of~he No B~ke type, which utilize an amine pol~ol. The binders are capablè of bonding sand or o*her foundry aggregate to forn molds or cores for ca~ing of metals, especially aluminum and ot~er light weigh~ me~a~s which a~e cast at relatlv~ly low temperature. The cores and molds made using these b~l~ers demonstrate superior collapslbility ~hen used at low casting tempera~ures~

DESCRIP~I~Y OF THE PRIOR ART

Urethane NQ Bake billders for use in bonding aggregate~ useful as fOUndl~r COTeS and molds are known in the art. U. 5. Patent No. 3,~76,3gZ is an ex2~p1e of such a No Ba~e bin~er composition and the use thereof ~o make cores and m~lds for ~oundr~r applications.

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~ lis in~en~ion is based in part upon the autocatalytic nature of amine polyols. A No Ba~e binder system for use in foundries is nol~ disclosed which can be a two component system instead of a typical urethane No Bake System which utili~es at le.~st three components.
Although the autocatalytic nature is a significant advanc~ment, this in~ention is not limited to such a system but may also incorporate a catalyst in certain embodiments. It is believed that utili~ation of an amine polyol in a No Bake System is in itself an advancement in the aTt o foundry binders.
This i~vention also emkodies another very important eature. A
~: long felt need in the foundry industry has been a No Bake binder for making castings for light metals such as aluminum and magnesium. ~le No Bake binders of the prior art weTe unable to provide cores and molds for casting these light weight metals having the required core and mold properties as well as good shakPout. Urethane No Bake binders based on phenolic, alkyd-oil and ;: polyester polyols aTe common in the found~y industry. However, when enough binder is used to achieve workable strength and abrasion resistance the cores and molds will not break do~n well at the casting temperatures of light metals. ~ :
That is9 ~ley exhibited poor shakeout. Non-urethane No Bake binders based on furan resins, phe~olic resins, al~yd resins, phosphate polymers and sodiu~
silicates are also kno~n and used, but suffer from the same sha~eout problem as described for the urethane No BaXe binders. There~ore, an existing problem has been. to find a binder that on the one hand produces stron~3 non-friable cores and molds and on ~he other hand bre~ks dow.n ~ell at ~he casting temper~
ature of aluminum and magnesium to pro~id~ easy shakéout.
.
BRIEF SU~4RY_OF~_THE~INVE~IION

It is an object of ~his in~ention to provide a foundry binder com-position using in admixture a pclyol and a polyisocyanate, wherein the polyol `

~Ol~ 51~ 7 is an ~mine polyol. The amune polyols of this inYention are normally ob~ained as the reaction product of an amine and an alXyler~e oxlde.
Another object of this invention is to provide urethane No Bake binder cor~ositions. It is further an object of this inven~ion to pro~ide urethane No Bake binders which can be used to produce cores and molds which have strength and non-friability but still break down well at low casting temperatures, i.e., below the casting temperatures of ferrous metals. The cores and molds exhîbit the combination o strength and easy shakeout at the casting temperatules of light weight metals such as aluminum and magnesium.
It has been found that a urethane binder formed as the reaction prod~ct of a polymeric isocyanate and an amine-based polyol can be used to make cores and molds. More specifi~ally it has been found ~hat a polyol which is the reaction product of an anine compound and an al~lene oxide will react with a polymeric isocyanate to produce a No Bake binder which, upon mix m g wnth sand or other suitable foundry aggregates, forms cores and molds possess-`~ ing excellent working characteristics, i.e., strength, abrasion resistanc~ and non-~riability. These properties are coupled with excellent shakeout character-istics when used in casting nonferrous metals. This co~bination of good wor~ing characteristics and excellent shakeout are especially significant and unique when the binder is used to ma~e cores intended for use in low temper-ature castIng. A catalyst is not necessarily a component of the ~Lnder system.
However, suitable catalysts can be utilized in the invention and are preferred with cert~in amine polyols when a rapid cure is needed.

DETAILED DESCRIPTION OF l~E INV~NTION
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The resin compositions of the present in~ention ind use as a tw~-part composition or system. Part one is the amine pol~ol. Part ~o is ~h~
polyisocyanate. Both parts are in liquid form and are generally solutions wit]l organic sol~en~s. At the time of use, that is to say l~len ~le urethane binder is formed~ the amine polyol part and the polyisocyanate part are com-1 ~ 5 5 9 bined and used f~r the in~ended application. In foundry application, i e.~the use of the compositions as a binder for cores and molds, it is preferTed to first admix one part with a fou~dry aggregate such as sand. Therea-fter, the second component is added and after achieving a uniform distribution of binder on the aggregate, the resulting foundry mi~ is formed or shaped into ~he desired shape. The shaped product can immediately be set aside and will cure to form a core or mold at room temperature. The conpositions of this invention are generally autocatalytic ~o a degree. That is, once the amine polyol and isocyanate are combined the reactivity of the polyol with the iso-cyanate is such that the reaction proceeds rapidly enough ~hat a catalyst isnot needed. The degree of reactivity of the amine polyol and polyisocyanate is dependent upon the reactivity of the polyol.
In spite of the fact that the co~?ositions are autccatalytic~ ~mine catalysts and metallic catalysts Xno~n in urethane technology may be e~ployed.
It should be noted that in some cases the ~;e of a catalyst l~ith the amine polyol and polyisocyanate components is beneficial and preferred. By selection af a proper catalyst, conditions of the core makin~ process, for examp}e ~rk time and strip time, can be adjusted as desired. In commercial practice it may be necessary to use a catalyst with certain polyols to obtain desired production rates.
The amm e polyols used to form the ure~ane binder c~mpositions o~
this invention are normally produced as ~he reacti~n product of an alkylene oxide and an amine compound. When ~he term "am m e polyol't is used herein it is meant ~o idenLify such reaction products but is not limited specifically to such means of synthesis. In general any polyol containing a~ least one or more terti~ry amine groups are considered to be wi~hin the scope of the de~Lnition of "amine polyol". The aIkylene oxides which are us~d to prepare the amine polyols are preferably ethylene oxide and prnpylene oxide. H~eve~, it appears easible to use other alkylene oxides as well. ~he amount of alkylene oxide in moles to moles o amine compound is subject to considerable ..

L~016 variation. It is believed ~hat ~he degree of alkoxylation does not detract from the ability of ~he resultant amine polyol to function as a binder.
The amine compounds which react with alkylene oxides to yîeld the amine polyols useful in the binder COmpOSitiQn constituting this invention include ammonia and mono and polyamino compounds with primary or secondary a~dno nitrogens. Specific examples include aliphatic amines such as prImary alkyl amines, ~thylene diamine, diethylene triamine and triethylene tetramine, cycloaliphatic amunes, aromatic amines, such as ortho-, meta~ and para-pheny-lene diamines, aniline-formaldehyde resins and the like. Blends of ~he amine polyols listed abo~e can also be utilized. In addition a blend of amIne polyols with other polyols is useful. In general it is belie~ed that amine containing compounds which when alkoxylated yield a polyol ~ith ~Yo or more reactive hydroxyl groups are useful in the compositions of this invention.
The second component or package of the novel binder composition com-prises an aliphatic, cycloaliphatic, or aromatic polyisocyanate having prefer-ably from 2 to 5 isocyanate groups. If desired, mixtu~es of polyisocyanates can be employed. Isocyanate prepolymers formed by reacting e~cess polyiso-cyanate with polyhydric alcohol e.g. a prepolymer of toluene diisocyanate and ethylene glycol, also can be employed. Suitable polyisocyanates mclude the aliphatic polyisocyanates su~h as hexamethyle~e diisocyanate3 alicyclic poly-lsocyanates such as 4,4'-dicyclohe~ylmethane diisocyanate~ and aromatic pol~r isocyanates such as 2,4-and 2S6-toluene diisocyanate, diphenylmethane di-isocyanate, and the dime~hyl derivatives ~hereof. Purther examples of suit-able polyisocyanates are 1,5-napthalene diisocyanate, triphenylmethane triiso-cyanate7xylylene diisocyanate, and ~he methyl derivatives thereof, polymethyl-enepolyph~nyl isocy~nates, chlorophenylene-2~ 4-diisocyanate; and ~he like.
Although all polyisocyanates react wi~h ~he amine polyol ~o fo~m ~ crosslinked polymer structure, the preferred polyisocyanates are aromatic polyisocyanates and particularly diphenylmethane diisocyanate, t~iphenylmethane triisocyana~e, and mixtures the~eof 401~ ~5~99~

The polyisocyana~e is generally employed in approximately a stoich-iometric amountD that is in sufficient concentra~ion to cause the curing of the amine polyol. However it is possible to deviate from this amount within limits and in some cases advantages may result. In general, the polyisocyan-ate will be employed in a range of lO to 500 weight percent based on the weight of ~he ~nine polyol. Preferably, from 20 to 300 weight percent of pol~-isocyanate on the same basis is employed. The polyisocyanate is employed in liquid ~o~m. Liquid polyisocyanates can be employed in undiluted form. Solid or viscous polyisocyanates are employed in the form of organic solvent solu-lQ tions, the solYent be m g present in a range of up to 80% by weight o-E the solution.
hlthough the salvent employed in combination with ~ither the amine polyol or the polyisocyanate or or both components does n~t enter to any significant degree into the reaction between the isscyanate and the amine polyol, it can affect the reaction. Thus the difEerence in the polarity between the polyisocyanate and the amine po:Lyol restricts the choice of sol-vents in which both components are compatib:Le. Such compatibility is neces-sary to achieve complete reaction and curing of the binder compositions of ~he present invention. Polar solvents of either the protic or aprotic type are good solvents ~or the amine polyol~ It is there~ore preferred to employ solvents or combinations of solvents where the solvent~s) for the polyol and for the polyisocyanate when mixed are compatible. In addition to compati~ility the solvents for either the polyol or polyisocyanate are selected to provide low viscosity~ low odor, high boiling point and inertness. Ex2mples of such solvents are ben~ene, toluene,~ylene, ethylbenzene, and mixtures ~hereof Preferred aromatic solvents are solvents and mL~tures thereof that have a high aromatic convent and a boiling point range within a range of 280 to 500 F. The polar solvents should not be extremely polar such as to become incom-patible when used in combination with the aromatic solvent. Sui~able polar solvents are generally those which have been classi~ied in the art as coupling ~016 solvents and :Lnclude furfural, Cellosolve, glycol diace~ate, bu~yl Cellosolve acetate, isophorone and the like. It is possible some reactive polyols may also be used as a solvent. In addition it should be noted that water has been found to be a suitable solvent for the amine polyol under cer~ain conditions.
The binder components are combined and then admixed with sand ar a similar foundry aggregate to form the foundry mix or the foundry mix can also be formed by sequentially adnixing the components l-rith the aggregate. Methodsof distributing the binder on the aggregate particles are well-known to those skilled in the art. The foundry max can, optionally, contain o~her ingredients such as iron oxide, ground flax fibers, wood cereals, pitch, refractory flours, and the like. The aggregate, e.g. sand, is usually the major constit-uent and the binder portion constitutes a rela~ively minor amount. ~lthough ~le sand employed is preferably dry sand, some moisture can be tolerated.
This is partic~arly true if the solvent en~loyed is non-~ater-miscible or if an excess of the polyisocyanate necessary for curing is employed, since such e~cess polyisocyanate will react with the water which as previously mentioned has been found to be a solvent for some amine polyols.
hs previously stated the excelle~t shakeout or collapsibility of cores made using the binder of this invention is deemed to be a significant discovery. The binders of this invention degrade or break dol~n easily to permlt separa*ion of *he core ~rom the cast metal. For cas~ings at low tem-peratures, e.g. 1800 F. or below~ shakeout has been a major problem. Gen- ;
erally nonferrous metals are cast a~ ~hese temperatures including aluminum and magnesium. Failu~e of ~he binder to break do~n causes great dif~iculty in removal of the sand from the casting. Thus cores exhibiting a low degree of shakeout or collapsibili*y9 that is to say a low degree of binder degra-dation~ require more time ~nd energy to remove the sand from the casting.
The use of the binder compositions of this inve-ntion results i~n many cases of virtually 100% shakeout without the application of any external energy. The improveme~t in shakeou~ is attributable to the presence of ~he amine polyol : , 1 ~55~9~

in the binder composition. As will be appreciatcd by ~hose skilled in ~he art, the ability of ~Iy core to sl~aXeout is dependent to an extent upon the amount of binder used to bond ~he sand particles into a coheren~ shape.
The percent binder utilized, based on the weight of the sand, depends upon the desired core properties which are required from the binder system. As can be-appreciated, as the amount of binder in the system increases an increase in the tensile strength of the core generally occurs. Accordingly, the binder level may be varied within reasonable limits to achieve the described performance properties. A preferred range of binder is, in this invention~ from 0.7~ to 2.5% based upon the weight of sand. However, it may be possible to use as little as 0.5% and as mwch as 10~ binder and still achieve properties which are of advantage in certain applications. However, it has also been noted that when the binder level is increased the degree of shakeout may decrease at the higher binder levels.
The present invention is further illustrated by the ~ollowing examples in which, unless othen~ise indicated, all parts are by weight and all percentages are weight percentages.

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~016 EX~LE 1 An amine polyol t~as prepared by propoxyla~ing 1.0 mole of ethylene diamine with 4.2 moles of propylene oxide. A 40~ solids solution of the amine polyol was ~repared by dissolving ~he polyol in an aromatic solvent commerciallyavailable under the brand name ~ISOL~ 10. This solution is referred to as Part I. A polymeric isocyanate solution, 75% solids, based on Mbndur MR, commercial-ly available from Mobay, was prepared using an aromatic solvent, also HISOL~ 10.Tne isocyanate solution is referred to as Part IIo ~ edron 501Q sand ~washed and dried, f~te gTained silica sand, AFSGFN
66) was placed in a suitable mixing apparatu~i. Part I was adm~ed with ~he sand until a unifonn coating ~as pTovided. Part II was added to the coated s~nd and blellded un~il a homogeneous sand mix was prepared. A near stoichio-metic amotmt of polyisocyanate, a slight excess, to completely react with the hydroxyl groups of -the polyol was used. One an a half percent (1~%) of total binder ~equal amounts of Part I and II~ by weight of sand was used.
~ he mix of sand, polyol and polyisoc~anate was placed in a core box a~d standard tensile briquettes, kn~.rn as "dog bones", were prepared. A work time of five and a half minutes ~nd a strip tIme of eigllt min~ltes was achieved.
Tensile str~ngths after t~o hours~ our hours and 24 hours were sOO, 371 ~Id 387 psi, respecti~ely.
The "dog bone" cores were used Ln sha~eout studies ~ith aluminum castings~ Seven ~ensile bTiquettes (dog bones) ~ere arranged in a mold. The mold incoTporated a gating syst~m~ The mold is designed to provide hollo~
cas~ings having a me~al thickness of approx~lately one-quarter inch on all sides. An opening at an end of the cas*ing is provided for removal of the core from th`e casting. hblten aluminum at approximately 130~)F. prepared fromaluminum ingots was poured into the mold. After cooling ~or abou~ an hour the aluminum castings are hro~cn from the gating system and remo~ed from the mold for shakeout testin~.
Shakeout tests are pcrformed by placing a casting in a one gallon container. The oontainer is placed on an agitating mechanism and tumbled for two minutes~ The weight of the sand core wllich is removed from the casting in this manner is compared to the initial weight of sand core and a percent shake-out is calculated. Sand remaining in the castin~ after the agitation de~cribed abo~e is removed by scraping and also weighed. The sand core, bonded with the amine polyol-polyisocyanate binder described above, collapsed and flowed out of the alumi~um casting without using the agitation mechanism ~nd ~nthout the application of any exte~nal mechanical energy. Shakeout was 100%.

EXA~LES 2-6 Using the procedures described in Example 1 dog bone tes~ coTes were prepared using the components and methods listed and descTibed below. The cores .
were used in shakeout tes~s using aluminum castings as described un Example 1.
ample 2 ample 3 Exam~le 4 F arnple 5 .~nple 6 Sand l~edron ~edron ~edron ~edTon ~l~ed~on Amine com- ~iethylene Triethylene Ethylene 20 pound Triamine Tetramine ~iamine Alkylene Propylene Propylene Plopylene Oxide (AO) Qxide Oxide Q~ide Mole Ratio 5.1:1 602:1 12:1 AO:amine ~mine Triethanol Qu.~DRoLb ~ Polyol amine from :: UPJOH~ra Poly- Mondur MR ~bndur MR ~bndur ~ Mondur ~ ndur isocy~nate Solvent in 40% 10% 60% 60~ 60%
Amine Polyol HISOL 10 ISOPHORO~E ISOPHORO~E HISOL 10 HISOL 10 Solvent in NONE NO~E 25~ 25% 25%
Polyisocy~nte HISOL 10 HISOL 10 HISOL 10 4016 ~ 3 ~

~x~npIe 2 Example 3 Example 4 Example 5 Example 6 Catalyst NONE NO~E NONE NONE NONE
ork Time 5 min. 2 min. 0,S min. 6 min. 5 min.
Strip T~ne 12 min. 4.5 min. 1.0 min. 9 min. 8 min.
Percent 1.5% 1.5Qo 1.5% 1.5~ 1.5%
Binder 40% Part I 50% Part I 60% Par~ I 50~ Part I 50% Part I
60% Part II SOO Part II 40~ Part II 50% Part II 50% Part II
Tensile Strength in psi

2 hr. lO0 153 85 360 339 4 hr. 118 210 113 365 350 24 hr. 163 247 ~- 230 383 Shakeout 100% 100% 100% 100% 100%
Cores made as described above were observed to collapse and fl~ out of the casting without using an agitation mechanism and witllout the applicationof any external mechanical energy.
a~PJOHN is a brand of triethanolamine9 i.e. ethoxylated ammonia, commercially available from ~john Corp.
- bQUADROL is the brand of propoxylated ethylene diamine, mole ratio of 4:13 commer d ally available from BASF IYyandotte.

EX~LE 7 An aromatic amine polyol was prepared by propoxylating one mole o~
me~a-phenylenediamine with 4.2 moles of propylene oxide. A 40% solids solution of the aromatic amine polyol was prepared by dissol~ing the polyol in an ;~ aliphatic solvent~ butyl Cellosolve. This solution is referred to as Part I.
A polymeric isocyanate solution9 75~ solids, based on M~n~ur ~, commercially a~ailable from Mobay9 was prepared using an aromatic solventl commercially available as HISOL~ 10. The isocyanate solution is ~eferred to as Part II.
A nearly stoichiometl~ic amount of polyisocyanate to completely react ~nth the llydroxyl groups of the polyol was used.

~016 ~L ~ 5 5~ 9 ~ r7 ~ Yedron 5010 s~ld (washed and dried, fine grained silica sand, AFSGFN
66) was placed in a suitable mixing apparatus~ Part I was admixed with the sand 7m til a 7~nifonn coa~ing was provided. Incorporated in Part I was a urethane catalys~, trie~hylenediamine, c~mercially availa51e under the brand name D~BCO~
~lis catalyst is a well kno~n urethane catalyst~ ~ased on the wei~ht of Part I,0.8% catalyst was used. Par~ as added to the coated sand and hlended until a homogeneous sand mox was prepared. One and a half percent (1~%) of total binder (Part I a7ld Part II) by weight of sand was used.
The mix of sand, pQlyOl, catalyst and polyisocyanate was placed in a core box and standard tensile briquettes, kno~n as "dog bones"~ were prepared.
A wor~ time of seventy minutes and a strip time of one hundred ten minutes was achieved. Tensile s~rength after 24 hours was 230 psi.
The "dog bone7' cores were used in shakeout studies with alumin~m castings. Seven tensile briquettes ~dog bones~ were arranged in a mold. The mold incorpora*ed a gating system. The mold .is designed ~o provide hollow castings havin~ a metal thickness o one-quarter inch on all sides. An opening at an end o the casting is provided for removal of the core fr~m the casting.
~lten alum~lum at approximately 1300 F. prepared frGm aluminum ingots was poured in~o the mold. After cooling for ab8ut an hour ~he aluminum c~s~ings were b~oken rom the gating system and ~moved from *he mold for shakeout testing~
Shakeout tests are perfoTmed by placing a casting in a one gallon container. The container is placed on an agitating mechanism and tumbled for two minutes. The weight of the sand core which is removed from ~he casting in ~his m~nner is compared ~o ~le ini~ial weight of sand core and a perce~t shakeout is calculated. Sand remaining in the casting af~er ~he agita~ion described above is removed by scraping and also ~eighedr Th~ sand core, bonded with the amine polyol-polyisocyanate-catalyst binder described above, collapsed and flow2d out of ~le aluminum cas~ing withou~ using the zgita~ion ~ - mec~nism and without the application of any external mecha~ical energy.
Shakeou~ was 100%.
i - 12 4~16 5~

EXA~LE 8-ll _ Using tlle procedures described in Example 7 dog bone test cores were prepared using the components and methods as described belo~. The cores weTe used in shakeout ~ests using aluminum eastings as described in EXample 7, E~ ample 11 Sand ~Tedron ~Yedron ~edron WedTo~
5010 5010 ~010 5010 Amine : Component Al~ylene Oxide Mble Ratio AO:amine Amine Polyol PluracolC PluracolC Pluracoid Pluracold ~:. 767 767 79S 795 Poly M~ndur MR Mbndur ~ ~ondur h~ ~londur isocyanate Solve~t in 40% 35% 35% 35%
~mine Polyol HISOL 10 ~Yater HISOL 10 HISOL 10 S~lvent in 44goe None 35%e 35Pe Polyisocyanate Catalyst ~1) 1.4% None None (1) 1~%
Work Time25 min. 10 min. 11.5 min. 7 min.
Strip Time 31 min. 16 min. 16 min. 10.5 min.
: ~ Percent 1~5~o 1.7% 1.5% 1.5%
Binder 50% Part I 60~ Part I 50% Part I 50~O Part I
50% Par~ II 40% Par~ II 50% Par~ II 50% Part II
Tensile S~reng~h in psi 2 hr. ~25 10~ 203 223 (3 hrsO) 4 hr. -. 128 (3 ~r) 213 210 ; 24 hr. 368 -- 323 320 Sha~eout 92% 100% 100%

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~016 ~ 5~97 Cores made as described above were observed to collapse and flow out of the oasting witl-out using an agi~a~ion mechanism and lnthout the application of any external mechanical energy.

(1) 50% phenylpropyl pyridine and 50~ of a lithium salt of a carboxylic acid.
c Pluracol 767 is a brand name for a propoxyla~ed aromatic amine-based polyol commeTcially available from BASF ~yandotte.
d Pluracol 795 is a brand name for an ethoxylated aromatic amine based polyol commercially available from BASF l~'yandotte.
e a blend of HISOL 10 and kerosene.

EXA~lPLE 12 ., ~.
; An aromatic amine polyol ~as prepared by propoxylating one mole of ortho-phenylenediamine with 4.2 moles of propylene oxide. A 40~ solids solu- ;tion of the aromatic amine polyol was prepared by dissolving the polyol in isophorone. This solution is referred to as Part I. A polymeric isocy~na~e, Mondur MR, is ~eferred to as Part IX. A nearly stoichiometric amo~nt of poly-isocyanate to completely react with the hydroxyl groups of the polyol was used.
Wed~on 5010 sand ~washed and dried, fine gralned silica s~nd, AFSGFN
66) was placed in a suitable mixing apparatus. Part I was admixed with the 5and until a uni~orm coating was pro~ided. Incorporated in Part I l~as a 33%
solution in dipropylene glycol of a urethane catalyst, triethylenediamine, commercially aYailable under the brand name nABCOo This ca~alyst is a well-known urethane catalyst. Based on the weighx of Part I, 1.0~ catalyst was used. Part II was added to the coated sand and blended until a homogeneous sand ~ix was prepared. One and a half percent ~1~%) of total binder ~55%
Part I and 45~ Par~ II) by weight of sand was used~
The mix of sand, polyol, catalyst and polyisocyanate was placed in a , ~Ql6 ; 1~55~7 .

core box and standard ~ensile briquettes, known as "dog bones~'~ were prepared.
A work tIme of nine minutes and a strip time of twenty minute~ was achieved.
Tensile strength in psi after 2 hours and 24 hours were 292 and 313, respec-tively.
The "dog bone'l cores were used in shakeout studies wnth aluminumcastings. Seven tensile briquettes (dog bones) were arranged in a mold. The mold incorporated a gating system. The mold is designed to provide holl~
castings having a metal thickness of one-quarter inch on all sidesO An opening at an end of the casting is provided for removal o the csre from the casting.
Molten aluminum at approximately 1300F p~epared from aluminum ingots was po~lred into the mold. After cooling for about an hour the alu~inun castings were broken from the gating system and removed from the mold for shakeout t~sting.
Shakeout tests are peTonmed by placing a castin~ m a one-gallon COntaineT. The container is placed on an agitating m~chanism and tumbled for two minutes. m e weight of the sand core which is removed from the casting in ~his manner is compared to the initial weight of sand core and a percent ', shakeout is calcula*ed Sand ~emaining in the cas~ing afteT the ag;tation described above is removed by scraping and also weighed. The sand core, ~ 20 bonded with the amine polyol-polyisocyanate-ca~alyst binder described abo~e~
; collapsed and flowed out of the aluminum cas~ing without using the agi~tion mechanisn and withou~ the application of any external mechanical energy.
., .
Shakeout was 100%.

E~MPLSS 13 lS

Using 'che pTocedures described in Example 12 dog bone test cores were prepared Usi3lg the com~onemts and methods as described below~ l~e cores . were used in shakeout tests using al~nin~n castings as described in Example 12.
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~016 ~ 599~
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Exa le 13 Exame~
Sand Wedron ~Yedron tiedron Amine Meta phenylene CURIT~NE103, Anile Component diamine an anile formalde-hyde resin fTom UpJohn Alkylene Propylene oxide Pr~pylene oxide Propylene oxide Oxide Mole Ratio AD:amine 4.2:1 4.2:1 2.2:1 Amine Polyol Polyisocyanate Mondur MR ~Iondur ~ Mondllr MR
Solvent in 60% Isophorone 60% Isophorone 60% (X) Amine Polyol Solvent in None None ~Tone Polyisocyana~e Catalyst None None 1% Dabco ~ork l`ime 45 min. 70 mi~. 70min.
, Strip Time 78 min. 131 m:~n. 140 mun.
Percent 1.5% 1.5% 1.5%
20 Binder . 55% Part I 73% Part I 61% Part I . -45% Part II 27% Par~ II 39% Part II
!~ ~ Tensile Strength -~ ~npsi:
. 2 h~. 145 23 4 hr. 307 24 hT. 320 140 180 .~ Shakeou~ 89% 100% 74%

(X) a blend of butyl cellosolve aceta~e (40%) and HISOL 10 (20~) 30 Cbres made as described above were observed to collapse and ~low out of the ; .
casting using a~ agita-tion mechanism, with the application of external mechanical energy.

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Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A binder composition useful for making shaped foundry articles for use in casting lightweight metals, which articles collapse after casting of said lightweight metals, comprising in admixture a polyol component and a liquid polyisocyanate component, said polyol component comprising an aromatic amine polyol.

2. The binder composition of Claim 1 wherein the aromatic amine polyol is the reaction product of an aromatic amine com-pound and an alkylene oxide.

3. The binder composition of Claim 2 wherein the aromatic amine compound comprises aniline.

4. The binder composition of Claim 2 wherein the aromatic amine compound comprises an aniline formaldehyde adduct.

5. The binder composition of Claim 2 wherein the alkylene oxide comprises propylene oxide.

6. The binder composition of Claim 2 wherein the alkylene oxide comprises ethylene oxide.

7. The binder composition of Claim 2 wherein the amine polyol component comprises a water solution.

8. The binder composition of Claim 2 wherein the amine polyol component comprises a solution of an organic solvent.

9. The binder composition of Claim 8 wherein the organic solvent comprises an aromatic organic solvent.

10. The binder composition of Claim 2 containing a curing catalyst, said catalyst comprising a liquid or solid urethane catalyst.

11. A binder composition useful for making shaped foundry articles for use in casting lightweight metals! which articles collapse after casting of said lightweight metals, comprising in admixture a polyol component and a liquid polyisocyanate component, said polyol component comprising an adduct of ammonia and an alkylene oxide.

12. The binder composition of Claim 11 wherein the polyol component comprises a water solution.

13. The binder composition of Claim 11 wherein the binder composition contains a curing catalyst, said catalyst comprising a liquid or solid urethane catalyst.

14. Process of forming shaped foundry articles for use in casting lightweight metals, which articles collapse after casting of said lightweight metals, comprising:
a) Forming a foundry mix by distributing on an aggregate a binding amount of up to 10%, based upon the weight of the aggregate, of a binder composition, said composition comprising in ad-mixture a polyol component and a liquid polyiso-cyanate component, said polyol component comprising an amine polyol.

b) Shaping the foundry mix into a desired foundry article; and c) Allowing the article to cure.

15. The process of Claim 14 wherein the amine polyol com-ponent is the reaction product of an aromatic amine compound and an alkylene oxide.

16. The process of Claim 15 wherein the alkylene oxide comprises propylene oxide.

17. The process of Claim 15` wherein the alkylene oxide comprises ethylene oxide.

18. The process of Claim 15 wherein the amine polyol com-ponent comprises a water solution.

19. The process of Claim 15 wherein the binder composition contains a curing catalyst, said catalyst comprising a liquid or solid urethane catalyst.

20. The process of Claim 15 wherein the aromatic amine compound comprises aniline.

21. The process of Claim 15 wherein the aromatic amine compound comprises an aniline formaldehyde adduct.

22. The process of Claim 15 wherein the amine polyol com-ponent comprises a solution of an organic solvent.

23. The process of Claim 15 wherein the amine polyol com-ponent comprises a solution of an aromatic organic solvent.

24. The process of Claim 14 wherein the amine polyol com-ponent is the reaction product of an aliphatic amine compound and an alkylene oxide.

25. The process of Claim 24 wherein the alkylene oxide comprises propylene oxide.

26. The process of Claim 24 wherein the alkylene oxide comprises ethylene oxide.

27. The process of Claim 24 wherein the amine polyol com-ponent comprises a water solution.

28. The process of Claim 24 wherein the binder composition contains a curing catalyst, said catalyst comprising a liquid or solid urethane catalyst.

29. The process of Claim 24 wherein the aliphatic amine compound comprises ethylene diamine.

30. The process of Claim 24 wherein the amine polyol com-ponent comprises a solution of an organic solvent.

31. The process of Claim 24 wherein the amine polyol com-ponent comprises a solution of an aromatic organic solvent.

32. The process of Claim 14 wherein the amine polyol comprises an admixture of an aliphatic: amine polyol and an aromatic amine polyol.

33. Process of casting lightweight metal articles, said metal articles being shaped by use of foundry articles, which foundry articles collapse after casting said metal articles com-prising:
a) Forming a foundry article as described in Claim 14;
b) Heating said lightweight metal until it melts and is castable;
c) Casting said lightweight metal using the shaped foundry article;
d) Allowing the cast metal to solidify; and e) Collapsing the foundry article and removing said collapsed foundry Article from the cast lightweight metal article.