JPS643586B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to resin binder compositions that are mixtures of amine-based polyols and polyisocyanates. These compositions can be cured with gaseous catalysts. In another aspect, the present invention relates to curable urethane binder compositions useful for bonding particulate solids. In particular, the present invention relates to cold box type binders using uncalcined and amine polyols. These binders bind sand or other foundry aggregates to form casting molds or cores for metals, particularly aluminum and other lightweight metals that are cast at relatively low temperatures. I can do it. Cores and molds made using these binders have excellent disintegration or sand-shedding properties when used at low casting temperatures. Urethane cold box binders for use in bonding aggregates used as foundry cores and molds are known to those skilled in the art. U.S. Pat. No. 3,409,579 describes examples of such cold box binder compositions and their use in the manufacture of foundry cores and molds. Cold box binder systems used in foundries are known to utilize amine polyols as a component of the binder composition. The use of amine polyols in cold box systems advances casting binder technology. Furthermore, urethane non-bake binders are known for use in bonding aggregates used as foundry cores and molds.
U.S. Pat. No. 3,676,392 describes examples of unfired binder compositions and their use in forming foundry cores and molds. The invention is based on the autocatalytic properties of monopartial amine polyols. It is known that the no-fire binder systems used in foundries can be converted to two-component systems instead of the typical urethane no-fire systems that use at least three components. Although autocatalysis is a significant advance, the present invention is not limited to such systems, and in some instances catalysts can be mixed. The invention also has extremely important properties. Traditional considerations in the foundry industry concern non-fired and cold box binders in the casting of light metals such as aluminum and magnesium. The unfired and cold box binders of the prior art do not allow these lightweight metal casting cores and molds to have the desired core and mold properties and good sand removal properties. If sufficient binder is used to achieve service strength and abrasion resistance, the core and mold will not fail at light metal casting temperatures. That is,
Shows poor sand removal properties. In practice, the problem was, on the one hand, to produce strong, non-brittle cores and molds, and, on the other hand, to find binders that fracture well at aluminum and magnesium casting temperatures and facilitate sanding. It is an object of the present invention to provide a casting binder composition using a polyol and a polyisocyanate in which the polyol is an amine polyol. The mixture can be cured with a gaseous catalyst. The amine polyol in the present invention is usually obtained as a reaction product of an amine and an alkylene oxide. Another object of the invention is to provide urethane unfired and cold box binder compositions. Yet another object of the present invention is to provide a urethane non-fired and cold box binder that is capable of producing strong, non-brittle cores and molds, yet breaks at low casting temperatures, i.e., below the casting temperature of ferrous metals. The core and mold of the present invention have the combined effect of ease of sand removal and strength at casting temperatures for light metals such as aluminum and magnesium. It has been discovered that urethane binders formed as reaction products of polymerized isocyanates and amine-based polyols can be used to make cores and molds. The binder cures rapidly using a gaseous tertiary amine catalyst. Polyols, which are the reaction products of amine compounds and alkylene oxides, are combined with polymerized isocyanates, mixed with sand or other suitable foundry aggregates, and cured to provide excellent working properties, namely strength, wear resistance, and It has been found to produce unfired or cold box binders that form brittle cores and molds. These properties can be combined with excellent grit properties when used in casting non-ferrous metals. This combination of good working properties and excellent sand-off properties is particularly remarkable and unique when the binder is used in the formation of cores intended for use in low-temperature castings. Catalysts can be used to cure the components of the binder system. Suitable catalysts for the cold box according to the invention are gaseous tertiary amines or amines which can be introduced as vapors. Trimethylamine, dimethylethylamine and triethylamine are preferred catalysts. Some catalysts do not require the components of a non-calcined binder system. However, suitable catalysts can be used in non-calcined binders, and certain amine polyols are preferred when rapid curing is required. It has been confirmed that the resin composition of the present invention can be used as a two-component composition or a two-component system. The first component is an amine polyol. The second component is a polyisocyanate. Both of these components are in liquid state, generally solutions in organic solvents. In use, the amine polyol component and the polyisocyanate component are mixed to form the so-called urethane binder and used for the intended application. In the foundry field, ie when the composition is used as a binder for cores and molds, it is preferred to first mix the first component with foundry aggregates such as sand. The second component is then added and the resulting casting mixture is formed or formed into the desired configuration after achieving a uniform distribution of binder on the aggregate. The formed product immediately hardens to form a core or mold at room temperature. The compositions of the invention are generally autocatalytic to some extent. That is,
Once the amine polyol and isocyanate are mixed, the reactivity of the polyol with the isocyanate is such that the reaction proceeds quickly enough without the need for a catalyst. The degree of reactivity of amine polyols and polyisocyanates is influenced by the reactivity of the polyol. The formed product can also be cured to form a core or mold by contacting the shape with a gaseous catalyst. Although the composition is autocatalytic, liquid amine catalysts and metal catalysts known in the urethane art can be used for non-calcination. In some cases it is advantageous to use catalysts with amine polyols and polyisocyanate components. The conditions of the core forming process, by selecting a suitable catalyst,
For example, the working time and stripping time can be adjusted as desired. In practice, the use of certain catalysts with certain polyols is required to obtain the desired production rate. Also, gaseous amine catalysts known in cold box technology can be used. The actual curing step consists of suspending the tertiary amine in a stream of inert gas and passing this tertiary amine-containing gas stream through the mold under sufficient pressure to infiltrate the molding until the resin is cured. This can be accomplished by The binder compositions of the present invention require only very short curing times to achieve acceptable tensile strength, a very important attribute. Optimal curing times can be easily established experimentally. Because the catalytic concentration of tertiary amine is required to effect cure, a stream can generally be made very dilute enough to effect cure. However, excess concentrations beyond those necessary for curing are not detrimental to the resulting cured product. An inert gas stream can be used, for example air containing 0.01 to 20% by volume of tertiary amine, carbon dioxide or nitrogen. Generally, the gaseous tertiary amine can be passed through the mold neat or in diluted form. Suitable tertiary amines include gaseous tertiary amines such as trimethylamine. However, normally liquid tertiary amines such as trimethylamine are suitable in a volatile state or suspended in a gaseous medium and then passed through a mold. Although ammonia, primary amines, and secondary amines exhibit some activity for cold reaction, the activity of these compounds is significantly less than that of tertiary amines. Functionally, substituted amines such as trimethylethanolamine fall within the scope of tertiary amines and can be used as curing agents. Functional groups that are not harmful to the action of the tertiary amide include hydroxyl groups, alkoxy groups, amines and alkylamino groups, ketooxy groups, thio groups, and the like. The amine polyols used to form the urethane binder compositions of the present invention are generally formed as reaction products of alkylene oxides and amine compounds. As used herein, "amine polyol" is meant to be identical to such reaction products, but is not specifically limited to such means of synthesis. Generally at least 1 or 2
Any polyol containing the above tertiary amine groups is considered to be within the definition of "amine polyol." Preferred alkylene oxides used to make amine polyols are ethylene oxide and propylene oxide. However, other alkylene oxides can be suitably used as well. The molar amount of alkylene oxide relative to the moles of amine compound can vary considerably. The degree of alkoxylation does not reduce the ability of the resulting amine polyol to act as a binder. The amine compounds react with alkylene oxides to produce amine polyols used in the binder composition of the present invention.
and mono- and polyamine compounds having secondary amino nitrogens. Particular examples of amine compounds include primary alkylamines, aliphatic amines such as ethylenediamine, diethylenetriamine and triethylenetetramine; cycloaliphatic amines; aromatic amines such as ortho-, meta- and para-phenylenediamine; aniline-formaldehyde Including resin etc. Also, mixtures of the above-mentioned amine polyols can be used. Additionally, mixtures of amine polyols and other polyols, ie non-amine polyols, can be used. Generally, amine-containing compounds that when alkoxylated yield polyols having two or more reactive hydroxyl groups can be used in the compositions of the present invention. The nature of the polyol component used is influenced by the conditions of the core forming process. In cold-boxing processes, ie, processes in which resin-coated sand is cured by amine-catalyzed gassing, an important property of the binder is the beuch bife. The pot life, which corresponds to the work time in an unfired system, is the elapsed time during which the resin-coated sand remains effective. After the binder is distributed on the aggregate, the binder begins to react. After a certain period of time, the reaction has progressed to such an extent that the resin-coated sand can no longer be used.
The sand coated with binder is then referred to as a "shot". The elapsed time after coating the sand with resin before the sand mixture becomes "shot" is known as the pot life in a cold-box system. It was determined that the pot life of the resin-coated sand was unexpectedly increased when aromatic initiated amine polyols were used. This unexpected result is both powerful and important. As mentioned above, it has been confirmed that polyhydroxyl compounds that can react with polyisocyanates are useful when blending or mixing amine polyols with other polyols. Its utility lies specifically in the box strength achieved after exposing the binder to the catalyst. Particularly preferred are the hydroxy-containing phenolic resins of US Pat. No. 3,485,797, known in the foundry industry as PEP resins. The second component or package of the novel binder composition preferably consists of an aliphatic, cycloaliphatic or aromatic polyisocyanate having 2 to 5 isocyanate groups. Mixtures of polyisocyanates can be used if desired. Also,
Isocyanate prepolymers formed by reacting excess polyisocyanate with prepolymers of polyhydric alcohols such as toluene diisocyanate and ethylene glycol can be used. Suitable polyisocyanates include aliphatic polyisocyanates such as hexamethylene diisocyanate; cycloaliphatic polyisocyanates such as 4,4'-dicyclohexylmethane diisocyanate; Includes aromatic polyisocyanates such as enylmethane diisocyanate and its dimethyl derivatives. Other examples of suitable polyisocyanates include 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate, xylylene diisocyanate and its methyl derivatives, polymethylene polyphenyl isocyanate and its methyl derivatives, chlorphenylene-2,4-diisocyanate, etc. can be mentioned. Although all polyisocyanates react with amine polyols to form crosslinked polymeric structures, the preferred polyisocyanates are aromatic polyisocyanates, particularly diphenylmethane diisocyanate, triphenylmethane triisocyanate, and mixtures thereof. Generally, the polyisocyanate is used in approximately stoichiometric amounts, ie, at a concentration sufficient to effect curing of the amine polyol. However, deviations from such usage amounts can be achieved with advantageous results in some cases. Generally, the polyisocyanate is 10% by weight of the amine polyol.
Used in the range of ~500% by weight, preferably 20~
Can be used at 300% by weight. Polyisocyanates are used in liquid form. Liquid polyisocyanates can be used undiluted. Solid or viscous polyisocyanates are used as solutions in organic solvents, with the solvent present in an amount up to 80% by weight of the solution. The solvent used in combination with the amine polyol or polyisocyanate, or for both components, can be reacted without being added to any sufficient extent to react the isocyanate with the amine polyol. For this reason, the difference in polarity between the polyisocyanate and the amine polyol limits the selection of solvents that make both components compatible. Such compatibility is necessary to achieve complete reaction and cure the binder compositions of the present invention. Polar solvents of the protic or aprotic type are good solvents for amine polyols. For this purpose, it is preferable to use solvents or solvent mixtures which, when mixed, are compatible with the solvent for the polyol and the solvent for the polyisocyanate. In addition to compatibility, the solvent for the polyol or polyisocyanate is selected to obtain low viscosity, low odor, high boiling point, and inertness. Such solvents include, for example, benzene,
Toluene, xylene, ethylenebenzene and mixtures thereof. Aromatic solvents are, for example, solvents and mixtures thereof with a high aromatic content and a boiling point in the range from 280 to 725°. Polar solvents should not be so extremely polar that they become incompatible when used in combination with aromatic solvents. in general,
Suitable polar solvents are those classified as coupling solvents and include, for example, furfural, cellosolve, glycol diacetate, butyl cellosolve acetate, isophorone, and the like. Also, certain reactive polyols can be used as solvents. Additionally, water has been determined to be a suitable solvent for amine polyols under certain conditions. The binder components may be mixed and then mixed with sand or similar casting aggregates to form a casting mixture, or such binder components may be sequentially mixed with aggregates to form a casting mixture. can. Methods of distributing binder on aggregate particles are well known to those skilled in the art. If necessary, the casting mixture may contain iron oxide, ground flax fiber, grain flour (wood
cereals), pituti, refractory powder
Other ingredients such as flours, etc. may also be included. The aggregates, or sand, usually constitute the main component, with the binder component being in a relatively minor amount. The sand used is preferably dry sand, although some moisture is acceptable. Particularly if the solvent used is incompatible with water or if there is an excess of polyisocyanate required for curing, such excess polyisocyanate will react with the water and the water will react with the amine polyol. It is a useful solvent. As mentioned above, the excellent sand removal property or disintegration stability of the core formed using the binder of the present invention is considered to be an important discovery. The binder in the present invention is susceptible to disintegration or breakage, facilitating separation of the core from the cast metal. In castings at low temperatures, for example 1800°C or less, shedding is a major problem. Generally, non-ferrous metals, including aluminum and magnesium, are cast at these temperatures. Failure of the destructive bonding agent makes it extremely difficult to remove sand from the casting. For this reason, cores exhibiting low sand-shedding or disintegration properties, ie, low binder disintegration, require time and energy to remove the sand from the casting. The use of the binder compositions of the present invention provides virtually 100% improvement without the use of any external energy in many cases.
It is possible to achieve sand removal. The improvement in sand-off properties is due to the presence of the amine polyol in the binder composition. The ability of any given core to shed sand is
It is influenced in part by the amount of binder used to bind the sand particles into a cohesive shape. The amount of binder used relative to the weight of sand is influenced by the desired core properties required from the binder system. As can be appreciated, increasing the amount of binder in the system generally increases the tensile strength of the core. Accordingly, the level of binder can be varied within reasonable limits to achieve the desired performance characteristics. In the present invention, the preferred range of binder is 0.7% to 2.5% by weight of sand. However, binders can be used in amounts as low as 0.5% and as high as 10% to achieve advantageous properties in certain applications. However, also when increasing the binder level, the degree of sand-shedding decreases at high binder levels. The invention will now be explained by way of example. All parts shown in the examples are by weight unless otherwise indicated;
In addition, all percentages indicate weight percent. Example 1 An amine polyol was made by propoxylation of approximately 1.0 moles of ethylene diamine and 4.2 moles of propylene oxide. A 40% solids solution of the amine polyol was made by dissolving the polyol in an aromatic solvent sold under the trade name "Hisol 10". Add this solution to the component (Part
). Based on the Mondur MR available from Mobay
A 75% polymerized isocyanate solution was made using an aromatic solvent, or "Hahisol 10". This isocyanate solution is called a component (Part). "Wedron 5010" sand (washed and dried fine granular silica sand "Afsgefn 66") was placed in a suitable mixing device. The above ingredients were mixed with this sand until a uniform coating was formed. The above ingredients were added to the evenly coated sand and mixed until a homogeneous sand mixture was obtained.A near stoichiometric amount of polyisocyanate was used with some excess to completely react with the hydroxyl groups of the polyol. A total binder of 11/2% by weight was used. The mixture of sand, polyol and polyisocyanate was placed in a core box and
They made standard tensile brigettes known as bones. A working time of 51/2 minutes and a stripping time of 8 minutes were achieved. The tensile strengths after 2 hours, 4 hours and 24 hours were 300, 371 and 387 psi, respectively. The "Dock Bone" core was used in a sand removal test using aluminum castings. Seven tensile briquettes (docked bones) were placed in the mold. The mold was combined with a gating system. The mold was designed to yield a hollow casting with approximately 11/4 inch metal thickness on all sides. A hole in one end of the casting was provided for removing the core from the casting. Approximately 1,300 ml of molten aluminum, made from an aluminum ingot, was poured into a mold. After cooling for approximately 1 hour, the aluminum casting was broken from the gate system and removed from the mold for sand drop testing. Shakeout tests were conducted with castings placed in one gallon containers. Place this container on the stirrer and
It was shaken for 2 minutes. The weight of the sand core thus removed from the casting was compared to the initial weight of the sand core and the percent shakeout was calculated.
After stirring as described above, the sand remaining in the casting was removed by scraping and weighed. Sand cores bonded by the amine polyol-polyisocyanate binder described above were broken and drained from aluminum castings without the use of a stirrer and without the application of any external mechanical energy. Sand drop rate is 100
It was %. Examples 2-6 Using the process described in Example 1 above, dogbone test cores were made using the components and methods shown in the following table. The cores were used in sand-drop tests using aluminum castings as described in Example 1.

TABLE Cores made as described above were observed for casting failure and spillage without the use of a stirrer and without any external mechanical energy. a Upjohn is the trade name for triethanolamine, i.e. ethoxylated ammonia, commercially available from Upjohn Corporation b Quadrol is the trade name of BASF
4:1 molar ratio commercially available from Wyandotte
Example 7 An aromatic amine polyol was made by propoxylating 1 mole of meta-phenylenediamine with 4.2 moles of propylene oxide. A 40% solids solution of aromatic amine polyol was made by dissolving the polyol in an aliphatic solvent, butyl cellosolve. This solution is called a component. A polymerized isocyanate solution (75% solids) based on "Monduille MR" commercially available from Mobai was prepared using "Hahisol 10" aromatic solvent. This isocyanate solution is referred to as a component. A stoichiometric amount of polyisocyanate was used to completely react with the hydroxy groups of the polyol. ``Uedron 5010'' sand (washed and dried fine granular silica sand, ``Afskefun 66'') was placed in a suitable mixing device. The ingredients were mixed into the sand until a uniform coating was formed. The ingredients were mixed with triethylenediamine, a urethane catalyst available under the trade name Dabco. This catalyst is a well-known urethane catalyst. 0.8 relative to the weight of the ingredients
% catalyst was used. The ingredients were added to the coated sand and mixed until a homogeneous sand mixture was obtained. 11/2%
% total binder by weight was used. A mixture of sand, polyol, catalyst, and polyisocyanate was placed in a core box to create a standard tensile bricade known as a "dock bone." A working time of 70 minutes and a stripping time of 110 minutes were achieved. Tensile strength after 24 hours was 230 psi. The "Dock Bone" core was used in a sand removal test using aluminum castings. Seven tensile briquettes (docked bones) were placed in the mold. The mold was combined with a gate system. The mold was designed to yield a hollow casting with approximately 11/4 inch metal thickness on all sides. A hole in one end of the casting was provided for removing the core from the casting. Approximately 1,300 ml of molten aluminum, made from an aluminum ingot, was poured into a mold. After cooling for approximately 1 hour, the aluminum casting was broken from the gate system and removed from the mold for sand drop testing. Shakeout tests were conducted with castings placed in one gallon containers. Place this container on the stirrer and
It was shaken for 2 minutes. The weight of the sand core thus removed from the casting was compared with the initial weight of the sand core to calculate the sand removal rate. After stirring as described above, the sand remaining in the casting was removed by scraping and weighed. A sand core bonded by the above-mentioned amine polyol-polyisocyanate-catalyst binder,
The aluminum casting was broken and drained without the use of an agitator and without the application of any external mechanical energy. The sand removal rate was 100%. Examples 8-11 Using the process described in Example 7 above, dogbone test cores were made using the components and methods shown in the following table. The cores were used in a sand drop test using aluminum castings as described in Example 7.

TABLE Cores made as described above were observed for casting failure and spillage without the use of a stirrer and without any external mechanical energy. (1) 50% phenylpropylpyrine and 50% lithium salt of a carboxylic acid. c Pluracol 767 is a propoxylated aromatic amine commercially available from Basf Wyandotte.
Product name of based polyol. d Pluracol 795 is a trade name for an ethoxylated aromatic amine-based polyol commercially available from Basf Wyandotte. e Trade name of Hahisol 10 and kerosene. Example 12 An aromatic amine polyol was added to 1 mole of ortho-
It was prepared by propoxylation of phenylene diamine with 4.2 moles of propylene oxide. A 40% solids solution of aromatic amine polyol was made by dissolving the polyol in isophorone. This solution is called a component. Polymerized isocyanate "Monduille MR" is called a component. A nearly stoichiometric amount of polyisocyanate was used to completely react with the hydroxy groups of the polyol. ``Uedron 5010'' sand (washed and dried fine granular silica sand, ``Afskefun 66'') was placed in a suitable mixing device. The ingredients were mixed into the sand until a uniform coating was formed. Ingredients include a urethane catalyst available under the trade name "Dabco" and 33% of dipropylene glycol of triethylenediamine.
% solutions were mixed. This catalyst is a well-known urethane catalyst. 1.0% catalyst was used based on the weight of the ingredients. The ingredients were added to the coated sand and mixed until a homogeneous sand mixture was obtained. 11/ for the weight of sand
2% by weight total binder (55% component and 45% component) was used. A mixture of sand, polyol, catalyst and polyisocyanate was placed in a core box to form a standard tensile briquette known as a "dock bone". A working time of 9 minutes and a stripping time of 20 minutes were achieved. The tensile strengths after 2 and 24 hours were 292 and 313 psi, respectively. The "Dock Bone" core was used in a sand removal test using aluminum castings. Seven tensile briquettes (docked bones) were placed in the mold. The mold was combined with a gate system. Place the mold on all sides about 1
It was designed to obtain a hollow casting with a metal thickness of 1/4 inch. A hole in one end of the casting was provided for removing the core from the casting. Approximately 1,300 ml of molten aluminum, made from an aluminum ingot, was poured into a mold. After cooling for approximately 1 hour, the aluminum casting was broken from the gate system and removed from the mold for sand drop testing. Sand drop tests were conducted with castings placed in one gallon containers. Place this container on the stirrer and
It was shaken for 2 minutes. The weight of the sand core thus removed from the casting was compared with the initial weight of the sand core to calculate the sand removal rate. After stirring as described above, the sand remaining in the casting was removed by scraping and weighed. A sand core bonded by the above-mentioned amine polyol-polyisocyanate-catalyst binder,
The aluminum casting was broken and drained without the use of a stirrer and without the application of any external mechanical energy. The sand removal rate was 100%. Examples 13-15 Using the process described in Example 12 above, dogbone test cores were made using the components and methods shown in the following table. The cores were used in sand drop tests using aluminum castings as described in Example 12.

【table】

[Table] The cores produced as described above were observed for fracture and outflow of the castings using a stirrer and applying external mechanical energy. Example 16 An amine polyol was made by propoxylation of about 1.0 moles of meta-phenylene diamine and 6.0 moles of propylene oxide. 40% solid solution of amine polyol, 40% isophorone solvent, 16.5
% aromatic solvent and 3.5% kerosene. This solution is called a component. Mondur MR available from Mobai
A 75% solids polymerized isocyanate solution based on MR) was prepared using an aromatic solvent, "Hahisol 10". This isocyanate solution is referred to as a component. A nearly stoichiometric amount of polyisocyanate was used to completely react with the hydroxy groups of the polyol. "Wedron 5010" sand (washed,
Dry fine granular silica sand, Afskehun 66'')
was placed in a suitable mixing device. The above ingredients were mixed into this sand until a uniform coating was formed. The above ingredients were added to this uniformly coated sand and mixed until a homogeneous sand mixture was obtained. 11/2% total binder (equal parts and components) based on the weight of the sand was used. A mixture of sand, polyol, and polyisocyanate was placed in a conventional core cavity or core box to create a standard tensile bricade known as a "dock bone." Dogbone test cores were cured by exposing the core to a tertiary amine catalyst.
The amine catalyst, dimethylethylamine, was suspended in carbon dioxide, an inert carrier gas. The cores were exposed to the amine catalyst for approximately 20 seconds (gas time) and were allowed to remain in the core box for 10 minutes (residence time) before being removed from the box. Tensile strength psi is 25 when taken out of the box, 72 after 1 hour and 72 after 24 hours.
It was 135. The "Dock Bone" core was used in a sand removal test using aluminum castings. Seven tensile briquettes (docked bones) were placed in the mold. The mold was combined with a gating system. The mold was designed to yield a hollow casting with approximately 11/4 inch metal thickness on all sides. A hole in one end of the casting was provided for removing the core from the casting. Approximately 1,300 ml of molten aluminum, made from an aluminum ingot, was poured into a mold. After cooling for approximately 1 hour, the aluminum casting was broken from the gate system and removed from the mold for sand drop testing. Sand drop tests were conducted with castings placed in one gallon containers. Place this container on the stirrer and
It was shaken for 2 minutes. The weight of the sand core thus removed from the casting was compared to the initial weight of the sand core and the percent shakeout was calculated.
After stirring as described above, the sand remaining in the casting was removed by scraping and weighed. Sand cores bonded by the amine polyol-polyisocyanate binder described above were broken and drained from aluminum castings without the use of a stirrer and without the application of any external mechanical energy. Sand drop rate is 100
It was %. Examples 17-21 Using the process described in Example 16 above, test cores were made using the ingredients and methods shown in the following table.

TABLE Cores made as described above were observed for casting failure and spillage without the use of a stirrer and without any external mechanical energy. Example 22 An amine polyol was made by propoxylating 1 mole of meta-phenylenediamine with 8.0 moles of propylene oxide. A polyol mixture was made by adding a phenolic polyol, available as a PEP resin, to an amine polyol. The ratio of o-amine polyol to non-amine polyol was 2:1. A 60% solids solution of the polyol mixture was made by dissolving the polyol mixture in isophorone solvent. This solution is designated as component I.
A polymerized isocyanate solution (75% solids) based on "Mondeul MR" was made using a solvent mixture consisting of "Texaco 7545", an aromatic solvent and 6% kerosene. This isocyanate solution is referred to as a component. A nearly stoichiometric amount of polyisocyanate was used to completely react with the hydroxy groups of the polyol. ``Uedron 5010'' sand (washed and dried fine granular silica sand, ``Afskefun 66'') was placed in a suitable mixing device. The ingredients were mixed into the sand until a uniform coating was formed. Add the ingredients to the coated sand,
Mixed until a homogeneous sand mixture was obtained. A total binder of 11/2% by weight based on the weight of the sand (44% component and 56% component) was used. A mixture of sand, polyol, and polyisocyanate was placed in a conventional core cavity or core box to create a standard tensile bricade known as a "dock bone." Dogbone test cores were cured by exposing the core to a tertiary amine catalyst.
The amine catalyst, dimethylethylamine, was suspended in carbon dioxide, an inert carrier gas. The cores were exposed to the amine catalyst for approximately 5 seconds (gas time) and were allowed to remain in the core box for 1 minute (residence time) before being removed from the box. Tensile strength psi was 58 out of the box, 200 after 1 hour and 210 at time of casting. The "Dock Bone" core was used in a sand removal test using aluminum castings. Seven tensile briquettes (docked bones) were placed in the mold. The mold was combined with a gate system. Place the mold on all sides about 1
It was designed to obtain a hollow casting with a metal thickness of 1/4 inch. A hole in one end of the casting was provided for removing the core from the casting. Approximately 1,300 ml of molten aluminum, made from an aluminum ingot, was poured into a mold. After cooling for approximately 1 hour, the aluminum casting was broken from the gate system and removed from the mold for sand drop testing. Sand drop tests were conducted with castings placed in one gallon containers. Place this container on the stirrer and
It was shaken for 2 minutes. The weight of the sand core thus removed from the casting was compared with the initial weight of the sand core to calculate the sand removal rate. After the above-mentioned stirring, the sand remaining in the casting was removed by scraping and weighed. Sand cores bonded by the amine polyol-polyisocyanate binder described above were used to break and drain aluminum castings without the use of a stirrer and without the application of any external mechanical energy. The sand removal rate was 100%. Examples 23-24

[Table] Sand core "Curithane 103"
The aluminum castings were bonded with an amine polyol derived from aniline formaldehyde resin available from Uption Corporation, and the aluminum castings were broken and drained without the use of a stirrer and without the application of any external energy. pullura call
A sand core based on 753 was vibrated to obtain the sand removal rate shown in the table. Example 25 An amine polyol was made by propoxylating 1.0 moles of ethylene diamine with 8.0 moles of propylene oxide. 50% solid solution of amine polyol, polyol in isophorone solvent
30%, aromatic solvent 16.5% and kerosene 35%. This solution is called a component. A polymerized isocyanate solution (75% solids) based on "Mondeul MR" was made using "Texaco 7545", 19% aromatic solvent and 6% kerosene. This isocyanate solution is referred to as a component.
A nearly stoichiometric amount of polyisocyanate was used to completely react with the hydroxy groups of the polyol. ``Uedron 5010'' sand (washed and dried fine granular silica sand, ``Afskefun 66'') was placed in a suitable mixing device. The ingredients were mixed into the sand until a uniform coating was formed. Add the ingredients to the coated sand,
Mixed until a homogeneous sand mixture was obtained. 11/2% by weight of total binder (equal parts and components) based on the weight of the sand was used. A mixture of sand, polyol, and polyisocyanate was placed in a conventional core cavity or box to create a standard tensile bricade known as a "dog bone." Dogbone test cores were cured by exposing the core to a tertiary amine catalyst, trimethylamine. The cores were exposed to the amine catalyst for approximately 10 seconds (gas time) and were allowed to remain in the core box for 5 minutes (residence time) before being removed from the box. The tensile strength psi was 80 at 15 minutes after degassing and 135 after 24 hours. The "Dock Bone" core was used in a sand removal test using aluminum castings. Seven tensile briquettes (docked bones) were placed in the mold. The mold was combined with a gate system. Place the mold on all sides about 1
It was designed to obtain a hollow casting with a metal thickness of 1/4 inch. A hole in one end of the casting was provided for removing the core from the casting. Approximately 1,300 ml of molten aluminum, made from an aluminum ingot, was poured into a mold. After cooling for approximately 1 hour, the aluminum casting was broken from the gate system and removed from the mold for sand drop testing. Sand drop tests were conducted with castings placed in one gallon containers. Place this container on the stirrer and
It was shaken for 2 minutes. The weight of the sand core thus removed from the casting was compared with the initial weight of the sand core to calculate the sand removal rate. After the above-mentioned stirring, the sand remaining in the casting was removed by scraping and weighed. Sand cores bonded by the amine polyol-polyisocyanate binder described above were used to break and drain aluminum castings without the use of a stirrer and without the application of any external mechanical energy. The sand removal rate was 100%. Example 26 A 58.5% solids solution of a phenolic polyol available as a PEP resin was made by dissolving the polyol in "Hysol 10". This solution is called a component. Polymerized isocyanate solution (75% solids) based on "Morduyur MR" is "Texaco 7545",
It was made using a solvent mixture consisting of 19% aromatic solvent and 6% kerosene. This isocyanate solution is referred to as a component. A stoichiometric amount of polyisocyanate was used to completely react with the hydroxy groups of the polyol. ``Uedron 5010'' sand (washed and dried fine granular silica sand, ``Afskefun 66'') was placed in a suitable mixing device. The ingredients were mixed into the sand until a uniform coating was formed. Add the ingredients to the coated sand,
Mixed until a homogeneous sand mixture was obtained. A total binder of 1.8% (equal parts and components) based on the weight of the sand was used. A mixture of sand, polyol, and polyisocyanate was placed in a conventional core cavity or box to form a standard tensile briquette known as a "dock bone." Dogbone test core,
The core was exposed to a tertiary amine catalyst and cured. The amine catalyst, dimethylethylamine, was suspended in carbon dioxide, an inert carrier gas. The core was exposed to the amine catalyst for approximately 1 second (gas time) and the core was immediately removed from the box. The tensile strength psi was 182 when immediately removed from the box (1 minute), 225 after 4 hours and 297 after 20 hours. The "Dock Bone" core was used in a sand removal test using aluminum castings. Seven tensile briquettes (docked bones) were placed in the mold. The mold was combined with a gate system. Place the mold on all sides about 1
It was designed to obtain a hollow casting with a metal thickness of 1/4 inch. A hole in one end of the casting was provided for removing the core from the casting. Approximately 1,300 ml of molten aluminum, made from an aluminum ingot, was poured into a mold. After cooling for approximately 1 hour, the aluminum casting was broken from the gate system and removed from the mold for sand drop testing. Sand drop tests were conducted with castings placed in one gallon containers. Place this container on the stirrer and
It was shaken for 2 minutes. The weight of the sand core thus removed from the casting was compared with the initial weight of the sand core to calculate the sand removal rate. After the above-mentioned stirring, the sand remaining in the casting was removed by scraping and weighed. The sand core bonded by the above-mentioned amine polyol-polyisocyanate binder was damaged by sand removal after stirring. The sand removal rate was 0%. Comparing this example with the examples described above, it can be seen that sand removal using an amine polyol in a cold box system is superior to other polyols used in a cold box system when making low temperature castings. Recognize.

Claims (1)

[Scope of Claims] 1. A method for casting a lightweight metal article using a casting article that is destroyed after casting the lightweight metal article, comprising: a. for binding up to 10% of aggregate based on the weight of the aggregate; forming a casting mixture by distributing a sufficient amount of a binder composition over the aggregate, such binder composition comprising a polyol component, a liquid polyisocyanate component, and such polyol component comprising an amine polyol; forming the casting mixture into the desired casting article; and curing the formed casting mixture; b. heating the lightweight metal until it is molten and ready to be cast; c. the formation so formed. d. solidifying the cast metal; and e. breaking the casting article and removing such broken casting article from the cast lightweight metal article. Method of casting articles. 2. The casting method according to claim 1, wherein the amine polyol component is a reaction product of an aromatic amine compound and an alkylene oxide. 3. The casting method according to claim 2, wherein the alkylene oxide is propylene oxide. 4. The casting method according to claim 2, wherein the alkylene oxide is ethylene oxide. 5. The casting method according to claim 2, wherein the amine polyol component is an aqueous solution. 6. The casting method according to claim 2, wherein the aromatic amine compound comprises aniline. 7. The casting method according to claim 2, wherein the aromatic amine compound is an aniline formaldehyde adduct. 8. The casting method according to claim 2, wherein the amine polyol is present in a solution of an organic solvent. 9. The casting method according to claim 2, wherein the amine polyol is present in a solution of an aromatic organic solvent. 10. The casting method according to claim 2, wherein the amine polyol component is a reaction product of an aliphatic amine compound and an alkylene oxide. 11. The casting method according to claim 10, wherein the alkylene oxide is propylene oxide. 12. The casting method according to claim 10, wherein the alkylene oxide is ethylene oxide. 13. The casting method according to claim 10, wherein the amine polyol component is an aqueous solution. 14. The casting method according to claim 10, wherein the aliphatic amine compound is ethylenediamine. 15. The casting method according to claim 10, wherein the amine polyol is present in a solution of an organic solvent. 16. The casting method according to claim 10, wherein the amine polyol is present in a solution of an aromatic organic solvent. 17. The casting method according to claim 10, wherein the amine polyol is a mixture of an aliphatic amine polyol and an aromatic amine polyol. 18 The polyol component is comprised of an amine polyol and a non-amine polyol.
The casting method described in item 0. 19. The casting method according to claim 1, wherein the binder is cured with a gaseous tertiary amine at room temperature. 20. The casting method according to claim 1, wherein the aggregate is sand. 21. The casting method according to claim 1, wherein the lightweight metal article to be cast is aluminum.