CA1223778A - Resin coated sand composition and method of producing same - Google Patents
Resin coated sand composition and method of producing sameInfo
- Publication number
- CA1223778A CA1223778A CA000432252A CA432252A CA1223778A CA 1223778 A CA1223778 A CA 1223778A CA 000432252 A CA000432252 A CA 000432252A CA 432252 A CA432252 A CA 432252A CA 1223778 A CA1223778 A CA 1223778A
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- CA
- Canada
- Prior art keywords
- phenolic resin
- resin
- parts
- coated sand
- phenolic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G16/00—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00
- C08G16/02—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00 of aldehydes
- C08G16/0212—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00 of aldehydes with acyclic or carbocyclic organic compounds
- C08G16/0218—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00 of aldehydes with acyclic or carbocyclic organic compounds containing atoms other than carbon and hydrogen
- C08G16/0231—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00 of aldehydes with acyclic or carbocyclic organic compounds containing atoms other than carbon and hydrogen containing nitrogen
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
- B22C1/02—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
- B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
- B22C1/20—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents
- B22C1/22—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents of resins or rosins
- B22C1/2233—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents of resins or rosins obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- B22C1/2246—Condensation polymers of aldehydes and ketones
- B22C1/2253—Condensation polymers of aldehydes and ketones with phenols
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G8/00—Condensation polymers of aldehydes or ketones with phenols only
- C08G8/04—Condensation polymers of aldehydes or ketones with phenols only of aldehydes
- C08G8/08—Condensation polymers of aldehydes or ketones with phenols only of aldehydes of formaldehyde, e.g. of formaldehyde formed in situ
- C08G8/16—Condensation polymers of aldehydes or ketones with phenols only of aldehydes of formaldehyde, e.g. of formaldehyde formed in situ with amino- or nitrophenols
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G8/00—Condensation polymers of aldehydes or ketones with phenols only
- C08G8/04—Condensation polymers of aldehydes or ketones with phenols only of aldehydes
- C08G8/08—Condensation polymers of aldehydes or ketones with phenols only of aldehydes of formaldehyde, e.g. of formaldehyde formed in situ
- C08G8/24—Condensation polymers of aldehydes or ketones with phenols only of aldehydes of formaldehyde, e.g. of formaldehyde formed in situ with mixtures of two or more phenols which are not covered by only one of the groups C08G8/10 - C08G8/20
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/16—Nitrogen-containing compounds
- C08K5/32—Compounds containing nitrogen bound to oxygen
Abstract
ABSTRACT
A resin coated sand for shell-molding foundry operations having improved shake-out properties for molds prepared therefrom is disclosed. Also disclosed are methods of producing said sand. The foundry aggregates or sand are coated with a phenolic resin containing from 0.2 to 40 parts of an aromatic nitro compound per 100 parts of phenolic resin. The resin may be a novolac type, a resole type or a mixture of the two types of phenolic resins. Suggested aromatic nitro compounds are nitrophenols, dinitrophenols and nitronaphthalenes. The process is extremely useful for coating lower melting temperature metals such as aluminum and magnesium.
A resin coated sand for shell-molding foundry operations having improved shake-out properties for molds prepared therefrom is disclosed. Also disclosed are methods of producing said sand. The foundry aggregates or sand are coated with a phenolic resin containing from 0.2 to 40 parts of an aromatic nitro compound per 100 parts of phenolic resin. The resin may be a novolac type, a resole type or a mixture of the two types of phenolic resins. Suggested aromatic nitro compounds are nitrophenols, dinitrophenols and nitronaphthalenes. The process is extremely useful for coating lower melting temperature metals such as aluminum and magnesium.
Description
i%2::177 !3 ~AC~GROUND OF THE INVENTIC)N
. ___ The present invention relates to an improved resin coated sand to be used in a shell-molding process. In conventional sand-molding operations, a mixture of sand coated with binder is ¦
placed in the mold, and the heat of the processing steps causes reactions to occur between the binder components to improve the pressed strength of the sand and retain the configuration of the part to be cast. After introduction of the molten metal into the cavity, the heat of the metal, during the cooling cycle is transferred to the sand-binder mixture causing the binder to be destro~ed to a degree that allows the sand to be removec~ from the cast metal in an efficient manne~.
In the automobile industry, the trend of manufacturers Il has led to the replacement of iron and steel castings ~ith 'I lighter weight metals such as aluminum, magnesium and their ¦ alloys. These castings are produced by sand-molding processes, but occur at lower temperatures than iron castings. The use of ~¦ conventional binders, at these lower temperatures, have created ' problems in the removal of the sand particles from the castings 1 due to the failure of the binder to be decomposed.
In the case of iron casting, the stock temperature of shell-mold reaches 800 - 1000C. at pouring, and the strength of shell-mold is naturally reduced after casting because almost all the phenolic resin binder is subjected to thermal degradation -25 by the intense heat at pouring. Accordingly, it is easy to remove the mold-core from molded articles in the form of sand grains after casting.
For metals having a lower melting temperature, such as aluminum and magnesium, the stock temperature of shell-mold at ~:
12~ 8 pouring is rather low, approximately 300 - 400C. This results in an incomplete thermal degradation of the phenolic resin binder.
Since conventional shell-molds have retained superfluous strength after casting for this reason, there have been extreme di~fi-culties particularly for complicated mold structures, in removingthe core efficiently from molded articles. In these cases, flogging is required so as to crush the molds even after time-¦¦ consuming calcination thereof in a furnace to remove the occluded ¦¦ core therefrom. Flogging is a term used to indicate a tapping ~l or impact force applied to the castings to remove the particulatesand particles leaving a clean cast structure.
After much inVestigation to improve the shake-out property of shell-mo~ds after casting metals having a lower ~I melting temperature, such as aluminum, the inventors have found I that the shake-out property of cast shell molds is greatly improved by using a resin-coated sand produced by coating foundry aggregates with a phenolic resin containing an aromatic nitro compound.
SUMMARY OF THE INVENTION
20 ~ This invention relates to resin coated sand for foundry shell-molding operations, and the process for preparing a binder-aggregate composition. The resin is a phenolic resin and can be selected from a novolac type, a resole type or a mixture of novolac and resole types. The phenolic resin contains an aromatic nitro compound such as a nitrophenol, dinitrophenol., dinitronaphthalene, etc. A lubricant can also be added to the phenolic resin.
~L223~
BRIEF DESCRIPTION OF DRAWING
The figure shows a side view of the testing device used to determine the shake-out properties of the formulation.
DETAILED DESCRIPTION OF THE INVENI'ION
This invention relates to coated-sand composition and a method for producing same, suitable for casting metals having a lower melting temperature compared with iron, such as aluminum lll and magnesium. In the case of iron casting, the stock temperaturq lll of shell-mold reaches 800 to 1000C. at pouring, and the strength 1l of shell-mold is naturally reduced a~ter casting because almost all -the phenolic resin binder thereof ls sub~ected -to -thermal degradation b~ the intense heat at pouring. Accordingly, it is easy to remove the mold-core from molded articles in the form of ~l sand grains after casting. For metals having a lower melting 15 ~ll temperature, such as aluminum and magnesium, said stock temper-¦l ature of shell-molds at pouring is rather low, 300 to 400C. in general. This results in an incomplete thermal degradation of 1~ phenolic resin binder employed therewith. Since conventional ¦I shell-molds have retained superfluous strength after casting for 1l this reason, there have been extreme difficulties particularly for complicated mold structures, in removing the core efficiently from m~lded articles. In these cases, flogging is required so as to crush the molds even after time-consuming calcination thereof in a furnace to remove the occluded core therefrom.
In order to improve the shake-out property after casting metals ha~ing a low melting temperature such as aluminum, the chemical crosslinking structure of cured phenolic resin l~Z3778 ¦I binders must thermally be degraded and cracked. In ordinary phenolic resins said chemical crosslinking structure therein consists of such as methylene, methine and dimethylene-ether groups. Among them, the dimethylene-ether group changes by heat to a methylene group. On the other hand, both the methylene~
i and methine gxoups are stable to thermal decomposition, and they re~uire much more energy for decomposition. Accordingly, in-corporating a substance, having a catalytic effect so as to lower I the activation energy of decomposition reaction of methylene and ~I methine groups, viz.; lowering the decomposition temperature of phenolic resins to 300 to 400C., is an effective method for causing a thermal disintegration of the sand mold.
' After much investigation in improving the shake-out Ij property of shell-molds made of coated sand obtained by coating l~ foundry aggregates with phenolic resins, the inventors hereof have Eound that the incorporation of aromatic nitro compounds in phenolic resins improves the shake-out property of shell-mold ~¦ obtained therefrom.
~ Said aromatic nitro compounds are o-nitrophenol, I p-nitrophenol, m-nitrophenol, 2,4-dinitrophenol, 2,5-dinitrophenol , ¦ 2,6-dinitrophencl, dinitronaphthalene, etc.; one or more thereof are employed in the present invention.
The most preferable incorporating proportion range of said aromatic nitro compounds is 0.2 to 40 against 100 parts by weight of a phenolic resin. When the proportion range is less than 0.2 parts it is difficult to obtain an excellent shake-out property, and when the proportion range is more than 40 parts by weight, it impairs properties such as the initial strength of the mold and curing characteristics thereof thus obtained.
The proper time for incorporating said aromatic nitro compounds during the process of preparing phenolic resin is I optional: at the beginning, during or after reacting phenols ¦I with formaldehyde. Or alternatively, after preparing said solid phenolic resin, said aromatic nitrophenols are incorporated thereinto by mix-grinding or melt-mixing with a kneading machine such as an extruder. It is also possible to incorporate the aromatic nitro compounds during resin coated-sand production Il steps; the proper time for incorporating the aromatic nitro ll compounds is optional: prior to, during or after adding the ¦ phenolic resin thereinto. The aromatic nitro compounds are in-corporated either as they are, or as dissolved in a solvent.
Any incorporating method improves the shake-out property of Il shell-molds obtained from resin coated-sand thus produced.
il 1 A phenolic resin according to the present invention is any of novolac type, resole type, and a mixture thereof.
Phenols, as raw materials in preparing a phenolic resin ~I hereof, are phenol, cresol, xylenol, etc., however, they are ¦¦ employed in the presence of resorcin, catechol, hydroquinone, ¦ urea, melamine, cashew nut shell oilt, etc.
¦ Formaldehyde for preparing said phenolic resins is selec-ted from formalin, paraformaldehyde, trioxane, etc. Reaction catalysts of phenol and formaldehyde for preparing novolacs are acidic substances, generally such as oxalic, hydrochloric and sulfuric acid. Basic substances are generally selected from such as ammonia, triethylamine, sodium hydroxide, barium hydroxide , etc., for resole type resin Preparation.
Lubricants are preferably employed in the present in-~ention, which are ordinary ones, however, more preferable are ethylene bis-stearic amide, methylene bis-stearic amide, oxy-stearic amide stearic amide and methyol stearic amide.
Lubricant-containing phenolic resins can be obtained by adding said lubricants to phenolic resins at any stage of their preparation; prior to, during or after the reac~ion.
Methods of producing resin coated-sand in the present invention may be any of the commercial hot-coating, semi-hot-coating, cold-coating, and powder-solvent coating, however, ~l hot-coating is preferably recommended for the present invention.
ll The inventors hereof will explain the present invention Il by the following nonlimitative Examples and Comparative Examples, 'I wherein "parts" and "percent" indicate "parts by weight" and "percent by weight", respectively.
Preparation Example 1 l To a reaction kettle with a reflux cooler and a stirrer, 1000 parts of phenol, 650 parts of 37~ formalin, and 10 parts of Il oxalic acid were charged. The temperature of the mixture was ¦ gradually elevated. When it reached 96C, it was held for 120 lj minutes reflux, 10 parts of methylene bis-stearic amide and 100 20 1I parts of 2,4-dinitrophenol were added thereto. After the mixture ¦ was further mixed and dispersed well, it was dehydrated under vacuum, and discharged out of the kettle. Thus, 1070 parts of a lubricant-containing novolac type resin were obtained. The I dinitrophenol content in 100 parts of the novolac type phenolic ¦ resin was 10 parts.
Preparation Example 2 Except for changing 2,4-dinitrophenol to dinitronaph-thalene 1070 parts of a lubricant-containing novolac type phenolic ~223778 resin were obtained by the sam~ conditions of Preparation Example 1. The content of said dinitronaphthalene in 100 parts of the novolac type phenolic resin was 10 parts.
Preparation Example 3 To a reaction kettle with a reflux cooler and a stirrer,¦
1000 parts of phenol, 1795 parts of 37~ formalin, 160 parts of 28~ aqueous ammonia solution, and 90 parts of 50% sodium hydroxidq ¦ solution were charged. The temperature of the mixture was ~ gradually elevatedO ~hen it reached 96C, it was held for 30 l! minutes reflux, 40 parts of methylene bis-stearic amide and 220 parts of 2,4-dinitrophenol were added thereto. After the mixture j was further mixed and dispersed weil, it was dehydrated under vacuum. It was discharged out of the kettle and chilled quickly.
I Thus, 1320 parts of a lubricant-containing resole type phenolic I resin were obtained. The content of said nitrophenol in 100 parts of the resole type phenolic resin was 20 parts.
Preparation Example 4 Except for changing 2,4-dinitrophenol to dinitronapthalenle, Il 1320 parts of a lubricant-containing resole type phenolic resin ¦ were obtained by the same conditions of Preparation Example 3.
The content of said nitrophenol in 100 parts of the resole type phenolic resin was 20 parts.
Preparation Example 5 To a reaction kettle with a reflux cooler and a stirrer, 1000 parts of phenol, 650 parts of 37% formalin, and 10 parts of oxalic acid were charged. The temperature of the mixture was gradually elevated. When it reached 96C, it was held for 30 minutes reflux, 10 parts of methylene bis-stearic amide were added thereto. After ~he mixture was further mixed and dispersed well, it was dehydrated under vacuum, and discharged out of the kettle.
Thus, 970 parts of a lubricant-containing novolac type phenolic resin were obtained.
Preparation Example 6 Except for charging 485 parts of 2,4--dinitrophenol at the time of charging the 10 parts of methylene bis-stearic amide Il thereto, 1455 parts of a lubricant-containing novolac type phenol~c Il resin were obtained by the same conditions of Preparation Example !
1 5. The content of said nitrophenol in 100 parts of the novolac type phenolic resin was 50 parts.
Preparation Example 7 Il To a reaction kettle with a reflux cooler and a stirrer, Il .
Il 1000 parts of phenol, 1795 parts of 37% formalin, 160 parts of 1 28% aqueous ammonia, and 60 parts of 50% sodium hydroxide solution were charged. The temperature of the mixture was gradually elevated. When it reached 96C, it was held for 30 minutes l~ reflux, 40 parts of methylene bis-stearic amide were added there-,l to. After the mixture was further well mixed, it was discharged 1 out of the kettle and chilled quickly. Thus, 1100 parts of a lubricant-containing resole type phenolic resin was obtained.
Example 1 Preheated at 130 to 140~C, 7000 parts of Sanei No. 6 silica sand were charged into a whirl-mixer. After 140 parts of lubricant-containing novolac type phenolic resin obtained ¦ according to Preparation Example 1 were added thereto, it was mixed for 40 seconds, and 21 parts of hexamethylene tetramine dissolved in 105 parts of water were added thereto. The mixture _g_ 1~23778 was further mixed well until it crumbled. 7 parts of calcium stearate were added thereto, and after 30 seconds mixing, it was discharged and aerated. Thus, a kind of resin coated-sand composition was obtained.
Example 2 Except for employing lubricant-conta:ining novolac type phenolic resin obtained according to Preparation Example 2, a kind of coated-sand composition was obtained by the same condi~
tions as Example 1.
I Example 3 Preheated at 130 to lqOC, 7000 parts of Sanei No. 6 silica sand were charged into a whirl-mixer. After 140 parts of lubricant-containing resole type phenolic resin obtained I according to Preparation Example 3 were added thereto, it was ,l mixed for 40 seconds. At this time 105 parts of cooling water were added thereto. The mixture was further mixed well until it crumbled. 7 parts of calcium stearate were added thereto and after 30 seconds mixing, it was discharged and aerated. Thus, a ~ kind of resin coated-sand composition was obtained.
ll Example 4 Except for employing lubricant-containing resole type phenolic resin obtained according to Preparation Example 4, a kind of coated-sand composition was obtained by the same conditions as Example 3.
. ___ The present invention relates to an improved resin coated sand to be used in a shell-molding process. In conventional sand-molding operations, a mixture of sand coated with binder is ¦
placed in the mold, and the heat of the processing steps causes reactions to occur between the binder components to improve the pressed strength of the sand and retain the configuration of the part to be cast. After introduction of the molten metal into the cavity, the heat of the metal, during the cooling cycle is transferred to the sand-binder mixture causing the binder to be destro~ed to a degree that allows the sand to be removec~ from the cast metal in an efficient manne~.
In the automobile industry, the trend of manufacturers Il has led to the replacement of iron and steel castings ~ith 'I lighter weight metals such as aluminum, magnesium and their ¦ alloys. These castings are produced by sand-molding processes, but occur at lower temperatures than iron castings. The use of ~¦ conventional binders, at these lower temperatures, have created ' problems in the removal of the sand particles from the castings 1 due to the failure of the binder to be decomposed.
In the case of iron casting, the stock temperature of shell-mold reaches 800 - 1000C. at pouring, and the strength of shell-mold is naturally reduced after casting because almost all the phenolic resin binder is subjected to thermal degradation -25 by the intense heat at pouring. Accordingly, it is easy to remove the mold-core from molded articles in the form of sand grains after casting.
For metals having a lower melting temperature, such as aluminum and magnesium, the stock temperature of shell-mold at ~:
12~ 8 pouring is rather low, approximately 300 - 400C. This results in an incomplete thermal degradation of the phenolic resin binder.
Since conventional shell-molds have retained superfluous strength after casting for this reason, there have been extreme di~fi-culties particularly for complicated mold structures, in removingthe core efficiently from molded articles. In these cases, flogging is required so as to crush the molds even after time-¦¦ consuming calcination thereof in a furnace to remove the occluded ¦¦ core therefrom. Flogging is a term used to indicate a tapping ~l or impact force applied to the castings to remove the particulatesand particles leaving a clean cast structure.
After much inVestigation to improve the shake-out property of shell-mo~ds after casting metals having a lower ~I melting temperature, such as aluminum, the inventors have found I that the shake-out property of cast shell molds is greatly improved by using a resin-coated sand produced by coating foundry aggregates with a phenolic resin containing an aromatic nitro compound.
SUMMARY OF THE INVENTION
20 ~ This invention relates to resin coated sand for foundry shell-molding operations, and the process for preparing a binder-aggregate composition. The resin is a phenolic resin and can be selected from a novolac type, a resole type or a mixture of novolac and resole types. The phenolic resin contains an aromatic nitro compound such as a nitrophenol, dinitrophenol., dinitronaphthalene, etc. A lubricant can also be added to the phenolic resin.
~L223~
BRIEF DESCRIPTION OF DRAWING
The figure shows a side view of the testing device used to determine the shake-out properties of the formulation.
DETAILED DESCRIPTION OF THE INVENI'ION
This invention relates to coated-sand composition and a method for producing same, suitable for casting metals having a lower melting temperature compared with iron, such as aluminum lll and magnesium. In the case of iron casting, the stock temperaturq lll of shell-mold reaches 800 to 1000C. at pouring, and the strength 1l of shell-mold is naturally reduced a~ter casting because almost all -the phenolic resin binder thereof ls sub~ected -to -thermal degradation b~ the intense heat at pouring. Accordingly, it is easy to remove the mold-core from molded articles in the form of ~l sand grains after casting. For metals having a lower melting 15 ~ll temperature, such as aluminum and magnesium, said stock temper-¦l ature of shell-molds at pouring is rather low, 300 to 400C. in general. This results in an incomplete thermal degradation of 1~ phenolic resin binder employed therewith. Since conventional ¦I shell-molds have retained superfluous strength after casting for 1l this reason, there have been extreme difficulties particularly for complicated mold structures, in removing the core efficiently from m~lded articles. In these cases, flogging is required so as to crush the molds even after time-consuming calcination thereof in a furnace to remove the occluded core therefrom.
In order to improve the shake-out property after casting metals ha~ing a low melting temperature such as aluminum, the chemical crosslinking structure of cured phenolic resin l~Z3778 ¦I binders must thermally be degraded and cracked. In ordinary phenolic resins said chemical crosslinking structure therein consists of such as methylene, methine and dimethylene-ether groups. Among them, the dimethylene-ether group changes by heat to a methylene group. On the other hand, both the methylene~
i and methine gxoups are stable to thermal decomposition, and they re~uire much more energy for decomposition. Accordingly, in-corporating a substance, having a catalytic effect so as to lower I the activation energy of decomposition reaction of methylene and ~I methine groups, viz.; lowering the decomposition temperature of phenolic resins to 300 to 400C., is an effective method for causing a thermal disintegration of the sand mold.
' After much investigation in improving the shake-out Ij property of shell-molds made of coated sand obtained by coating l~ foundry aggregates with phenolic resins, the inventors hereof have Eound that the incorporation of aromatic nitro compounds in phenolic resins improves the shake-out property of shell-mold ~¦ obtained therefrom.
~ Said aromatic nitro compounds are o-nitrophenol, I p-nitrophenol, m-nitrophenol, 2,4-dinitrophenol, 2,5-dinitrophenol , ¦ 2,6-dinitrophencl, dinitronaphthalene, etc.; one or more thereof are employed in the present invention.
The most preferable incorporating proportion range of said aromatic nitro compounds is 0.2 to 40 against 100 parts by weight of a phenolic resin. When the proportion range is less than 0.2 parts it is difficult to obtain an excellent shake-out property, and when the proportion range is more than 40 parts by weight, it impairs properties such as the initial strength of the mold and curing characteristics thereof thus obtained.
The proper time for incorporating said aromatic nitro compounds during the process of preparing phenolic resin is I optional: at the beginning, during or after reacting phenols ¦I with formaldehyde. Or alternatively, after preparing said solid phenolic resin, said aromatic nitrophenols are incorporated thereinto by mix-grinding or melt-mixing with a kneading machine such as an extruder. It is also possible to incorporate the aromatic nitro compounds during resin coated-sand production Il steps; the proper time for incorporating the aromatic nitro ll compounds is optional: prior to, during or after adding the ¦ phenolic resin thereinto. The aromatic nitro compounds are in-corporated either as they are, or as dissolved in a solvent.
Any incorporating method improves the shake-out property of Il shell-molds obtained from resin coated-sand thus produced.
il 1 A phenolic resin according to the present invention is any of novolac type, resole type, and a mixture thereof.
Phenols, as raw materials in preparing a phenolic resin ~I hereof, are phenol, cresol, xylenol, etc., however, they are ¦¦ employed in the presence of resorcin, catechol, hydroquinone, ¦ urea, melamine, cashew nut shell oilt, etc.
¦ Formaldehyde for preparing said phenolic resins is selec-ted from formalin, paraformaldehyde, trioxane, etc. Reaction catalysts of phenol and formaldehyde for preparing novolacs are acidic substances, generally such as oxalic, hydrochloric and sulfuric acid. Basic substances are generally selected from such as ammonia, triethylamine, sodium hydroxide, barium hydroxide , etc., for resole type resin Preparation.
Lubricants are preferably employed in the present in-~ention, which are ordinary ones, however, more preferable are ethylene bis-stearic amide, methylene bis-stearic amide, oxy-stearic amide stearic amide and methyol stearic amide.
Lubricant-containing phenolic resins can be obtained by adding said lubricants to phenolic resins at any stage of their preparation; prior to, during or after the reac~ion.
Methods of producing resin coated-sand in the present invention may be any of the commercial hot-coating, semi-hot-coating, cold-coating, and powder-solvent coating, however, ~l hot-coating is preferably recommended for the present invention.
ll The inventors hereof will explain the present invention Il by the following nonlimitative Examples and Comparative Examples, 'I wherein "parts" and "percent" indicate "parts by weight" and "percent by weight", respectively.
Preparation Example 1 l To a reaction kettle with a reflux cooler and a stirrer, 1000 parts of phenol, 650 parts of 37~ formalin, and 10 parts of Il oxalic acid were charged. The temperature of the mixture was ¦ gradually elevated. When it reached 96C, it was held for 120 lj minutes reflux, 10 parts of methylene bis-stearic amide and 100 20 1I parts of 2,4-dinitrophenol were added thereto. After the mixture ¦ was further mixed and dispersed well, it was dehydrated under vacuum, and discharged out of the kettle. Thus, 1070 parts of a lubricant-containing novolac type resin were obtained. The I dinitrophenol content in 100 parts of the novolac type phenolic ¦ resin was 10 parts.
Preparation Example 2 Except for changing 2,4-dinitrophenol to dinitronaph-thalene 1070 parts of a lubricant-containing novolac type phenolic ~223778 resin were obtained by the sam~ conditions of Preparation Example 1. The content of said dinitronaphthalene in 100 parts of the novolac type phenolic resin was 10 parts.
Preparation Example 3 To a reaction kettle with a reflux cooler and a stirrer,¦
1000 parts of phenol, 1795 parts of 37~ formalin, 160 parts of 28~ aqueous ammonia solution, and 90 parts of 50% sodium hydroxidq ¦ solution were charged. The temperature of the mixture was ~ gradually elevatedO ~hen it reached 96C, it was held for 30 l! minutes reflux, 40 parts of methylene bis-stearic amide and 220 parts of 2,4-dinitrophenol were added thereto. After the mixture j was further mixed and dispersed weil, it was dehydrated under vacuum. It was discharged out of the kettle and chilled quickly.
I Thus, 1320 parts of a lubricant-containing resole type phenolic I resin were obtained. The content of said nitrophenol in 100 parts of the resole type phenolic resin was 20 parts.
Preparation Example 4 Except for changing 2,4-dinitrophenol to dinitronapthalenle, Il 1320 parts of a lubricant-containing resole type phenolic resin ¦ were obtained by the same conditions of Preparation Example 3.
The content of said nitrophenol in 100 parts of the resole type phenolic resin was 20 parts.
Preparation Example 5 To a reaction kettle with a reflux cooler and a stirrer, 1000 parts of phenol, 650 parts of 37% formalin, and 10 parts of oxalic acid were charged. The temperature of the mixture was gradually elevated. When it reached 96C, it was held for 30 minutes reflux, 10 parts of methylene bis-stearic amide were added thereto. After ~he mixture was further mixed and dispersed well, it was dehydrated under vacuum, and discharged out of the kettle.
Thus, 970 parts of a lubricant-containing novolac type phenolic resin were obtained.
Preparation Example 6 Except for charging 485 parts of 2,4--dinitrophenol at the time of charging the 10 parts of methylene bis-stearic amide Il thereto, 1455 parts of a lubricant-containing novolac type phenol~c Il resin were obtained by the same conditions of Preparation Example !
1 5. The content of said nitrophenol in 100 parts of the novolac type phenolic resin was 50 parts.
Preparation Example 7 Il To a reaction kettle with a reflux cooler and a stirrer, Il .
Il 1000 parts of phenol, 1795 parts of 37% formalin, 160 parts of 1 28% aqueous ammonia, and 60 parts of 50% sodium hydroxide solution were charged. The temperature of the mixture was gradually elevated. When it reached 96C, it was held for 30 minutes l~ reflux, 40 parts of methylene bis-stearic amide were added there-,l to. After the mixture was further well mixed, it was discharged 1 out of the kettle and chilled quickly. Thus, 1100 parts of a lubricant-containing resole type phenolic resin was obtained.
Example 1 Preheated at 130 to 140~C, 7000 parts of Sanei No. 6 silica sand were charged into a whirl-mixer. After 140 parts of lubricant-containing novolac type phenolic resin obtained ¦ according to Preparation Example 1 were added thereto, it was mixed for 40 seconds, and 21 parts of hexamethylene tetramine dissolved in 105 parts of water were added thereto. The mixture _g_ 1~23778 was further mixed well until it crumbled. 7 parts of calcium stearate were added thereto, and after 30 seconds mixing, it was discharged and aerated. Thus, a kind of resin coated-sand composition was obtained.
Example 2 Except for employing lubricant-conta:ining novolac type phenolic resin obtained according to Preparation Example 2, a kind of coated-sand composition was obtained by the same condi~
tions as Example 1.
I Example 3 Preheated at 130 to lqOC, 7000 parts of Sanei No. 6 silica sand were charged into a whirl-mixer. After 140 parts of lubricant-containing resole type phenolic resin obtained I according to Preparation Example 3 were added thereto, it was ,l mixed for 40 seconds. At this time 105 parts of cooling water were added thereto. The mixture was further mixed well until it crumbled. 7 parts of calcium stearate were added thereto and after 30 seconds mixing, it was discharged and aerated. Thus, a ~ kind of resin coated-sand composition was obtained.
ll Example 4 Except for employing lubricant-containing resole type phenolic resin obtained according to Preparation Example 4, a kind of coated-sand composition was obtained by the same conditions as Example 3.
2~ I Example 5 i Preheated at 130 to 140C, 7000 parts of Sanei No. 6 silica sand were charged into a whirl-mixer and successively 130 parts of lubricant-containing novolac type phenolic resin obtainec ~ -10-~3 778 according to Preparation Example S were added thereto. Pollowed ~ by 20 seconds mixing, 13 parts of 2,4-dinitrophenol were added ¦! thereto. After it was mixed for 20 seconds, 21 parts of hexa-¦¦ methylene tetramine dissolved in 105 parts of water were added ¦ thereto. The mixture was further mixed until it crumbled.
7 parts of calcium stearate was added thereto, followed by 30 seconds mixing, it was discharged and aerated. Thus, a kind of resin coated-sand composition was obtained.
Il Example 6 ¦¦ Preheated at 130 to 140C, 7000 parts of Sanei No. 6 silica sand were charged into a whirl-mixer. After 13 parts of 1 2,4-dinitrophenol were added thereto, it was mixed for 20 seconds.
! I Successively 78 parts of lubricant-containing novolac type I phenolic resin according to Preparation Example 5 and 52 parts ll of lubricant-containing resole type phenolic resin according to Preparation Example 7 were added thereto, and the mixture was mixed well for 20 seconds. At this time 13 parts of hexamethylen~
tetramine dissolved in 63 parts by weight of water were added ' thereto. The mixture was mixed well until it crumbled. 7 parts ¦~ of calcium stearate were added thereto, and after 30 seconds mixing, it was discharged and aerated. Thus, a kind of resin coated-sand composition was obtained.
Comparative Example 1 Preheated at 130 to 140C, 7000 parts of Sanei No. 6 silica sand were charged into a whirl-mixer. After 140 parts of novolac type phenolic resin obtained according to Preparation Example 5 were added thereto, it was mixed for 40 seconds, and 21 parts of hexamethylene tetramine dissolved in 105 paxts of water were added thereto. The mixture was mixed well until it :
12~:3~7~1 ¦ crumbled. 7 parts of calcium stearate were added thereto, and after 30 seconds mixing, it was discharged and aeratedO Thus, a kind of resin coated-sand composition was obtained.
Comparative Example 2 5 ~ Except for employing lubricant-containing novolac type phenolic resin obtained according to Preparation Example 6, a kind of resin coated-sand composition was obtained by the same conditions as Comparative Example 1.
1~ Comparative Example 3 ll Preheated at 130 to 140C, 7000 parts of Sanei No. 6 silica sand were charged into a whirl-mixer. After 140 parts of resole type phenolic resin obtained according to Preparation ¦ Example 7 were added thereto, it was mixed for 40 seconds, and 105 parts of water were added thereto. The mixture was mixed 11 ¦ well until it crumbled. 7 parts of calcium stearate were added ¦ thereto, it was mixed for 40 seconds, and 105 parts of water were¦
added thereto. The mixture was mixed well until it crumbled.
7 parts of calcium stearate were added thereto, and after 30 seconds mixing, it was discharged and aerated. Thus, a kind ¦¦ of resin coated-sand composition was obtained.
¦I Table 1 indicates the characteristics of various kinds of coated-sand composition obtained according to Examles 1, 2, 3, 4, 5, and 6 and Comparative Examples 1, 2, and 3 as well as the shake-out property of she11-molds therefrom.
! I 1 j ~ ~ I I
O i i r-l ~ ~ ,1 C I I C~ I r . O ~
~ ~: I ~ ~ u~ a~, ~1 ~ 6 ! ~ c i I
-i r~ ¦ c~J ~ 3 ! ! i --I I c ~
n, ~ ~ I ~ i . ~
I `, 1 o~ l I ~
I ,`D ~ +! u O ~
C c I ~ ~
I ~ C I C ~D ¦ ~ ~ . ~ I ` !
j I j ~ C i c~ ' r.~l , j I ! r.~l ~1 3 ! l I I
~----~r~ ~ ~
~ ,C I r~l I cl~ c~ .
iD I, ~3C~ I
c ~ . ~ I ~ I r~
r~l ~ 3 ' ,11 I j ' ! i i I i i ' l l . I C l l -n ' o I ~D i r~ ¦ I
I i ~; r.~l ' o ~ O ~ t I r~ u) ~ I ~ i I ~ i' I I i I
ll I ,c~ ! L ~
I _ __ ~ . .~
I I I ~ l rl ~ j rn ¦ O
~ 1 O r~ O r.~ rn ~7 I IJ ~ t- i 1 e I ~ ¦ e ~3 ~ r I r E ¦
x ! ~n a~ .. , ~ o ~ I o ~, h i i I u ~0 c~ ~ ~ ~D _~
~4 ~ I r,q :~: _ . u Il o ' ~ ~ c) i ! ~- ~ o "I
r~ j ~ h O
~) 1:: ~ ! c c ~ ~ r~ ~o r~ 0 1 o ~ I al ~ ~ c ~ ~: Ll ~ I
C) ~ .C U~ I ~ ~ r,o ~ ~ ~~ rJ rn i3 ~ I ~ . _ _ ~ ¦ ~ I o 3 ~ e ¦ i h ~ ¦
C) i~l r~
o O
I O h h ~ 1 ¦ r l ~2~
Procedures used for testing of samples in Table 1.
Bending streng~h: according to JACT Method SM-l Stick point: according to JACT Method C-l Tensile strength under elevated temperature:
according to JACT Method SM-10 Shake-out property:
Preparation of specimen:
¦¦ Coated sand is fed into an iron pipe of 29mm il in diameter and 150mm length. After 30 l minutes baking, it is covered with aluminum 10 ~I foil and further heated for 3 hours at 370C.
After cooling, the sand molded pipe is removed.
1ll Test method:
;~I The specimen is flogged by the impact arm of the apparatus illustrated in Fig. 1. Crumbled 15 1I sand is removed from the pipe after each l flogging. Weighing the residual molded sand of the specimen until it becomes zero, and the shake-out property is defined by the number of `I floggings required.
20 ~ Test apparatus:
In Fig. 1, A is a molded sand specimen and B is the arm which revolves around pivot C set at 30cm high. Said arm is at first set horizontally, and then allowed to drop so as 25 ~ to flog the specimen.
-l4-
7 parts of calcium stearate was added thereto, followed by 30 seconds mixing, it was discharged and aerated. Thus, a kind of resin coated-sand composition was obtained.
Il Example 6 ¦¦ Preheated at 130 to 140C, 7000 parts of Sanei No. 6 silica sand were charged into a whirl-mixer. After 13 parts of 1 2,4-dinitrophenol were added thereto, it was mixed for 20 seconds.
! I Successively 78 parts of lubricant-containing novolac type I phenolic resin according to Preparation Example 5 and 52 parts ll of lubricant-containing resole type phenolic resin according to Preparation Example 7 were added thereto, and the mixture was mixed well for 20 seconds. At this time 13 parts of hexamethylen~
tetramine dissolved in 63 parts by weight of water were added ' thereto. The mixture was mixed well until it crumbled. 7 parts ¦~ of calcium stearate were added thereto, and after 30 seconds mixing, it was discharged and aerated. Thus, a kind of resin coated-sand composition was obtained.
Comparative Example 1 Preheated at 130 to 140C, 7000 parts of Sanei No. 6 silica sand were charged into a whirl-mixer. After 140 parts of novolac type phenolic resin obtained according to Preparation Example 5 were added thereto, it was mixed for 40 seconds, and 21 parts of hexamethylene tetramine dissolved in 105 paxts of water were added thereto. The mixture was mixed well until it :
12~:3~7~1 ¦ crumbled. 7 parts of calcium stearate were added thereto, and after 30 seconds mixing, it was discharged and aeratedO Thus, a kind of resin coated-sand composition was obtained.
Comparative Example 2 5 ~ Except for employing lubricant-containing novolac type phenolic resin obtained according to Preparation Example 6, a kind of resin coated-sand composition was obtained by the same conditions as Comparative Example 1.
1~ Comparative Example 3 ll Preheated at 130 to 140C, 7000 parts of Sanei No. 6 silica sand were charged into a whirl-mixer. After 140 parts of resole type phenolic resin obtained according to Preparation ¦ Example 7 were added thereto, it was mixed for 40 seconds, and 105 parts of water were added thereto. The mixture was mixed 11 ¦ well until it crumbled. 7 parts of calcium stearate were added ¦ thereto, it was mixed for 40 seconds, and 105 parts of water were¦
added thereto. The mixture was mixed well until it crumbled.
7 parts of calcium stearate were added thereto, and after 30 seconds mixing, it was discharged and aerated. Thus, a kind ¦¦ of resin coated-sand composition was obtained.
¦I Table 1 indicates the characteristics of various kinds of coated-sand composition obtained according to Examles 1, 2, 3, 4, 5, and 6 and Comparative Examples 1, 2, and 3 as well as the shake-out property of she11-molds therefrom.
! I 1 j ~ ~ I I
O i i r-l ~ ~ ,1 C I I C~ I r . O ~
~ ~: I ~ ~ u~ a~, ~1 ~ 6 ! ~ c i I
-i r~ ¦ c~J ~ 3 ! ! i --I I c ~
n, ~ ~ I ~ i . ~
I `, 1 o~ l I ~
I ,`D ~ +! u O ~
C c I ~ ~
I ~ C I C ~D ¦ ~ ~ . ~ I ` !
j I j ~ C i c~ ' r.~l , j I ! r.~l ~1 3 ! l I I
~----~r~ ~ ~
~ ,C I r~l I cl~ c~ .
iD I, ~3C~ I
c ~ . ~ I ~ I r~
r~l ~ 3 ' ,11 I j ' ! i i I i i ' l l . I C l l -n ' o I ~D i r~ ¦ I
I i ~; r.~l ' o ~ O ~ t I r~ u) ~ I ~ i I ~ i' I I i I
ll I ,c~ ! L ~
I _ __ ~ . .~
I I I ~ l rl ~ j rn ¦ O
~ 1 O r~ O r.~ rn ~7 I IJ ~ t- i 1 e I ~ ¦ e ~3 ~ r I r E ¦
x ! ~n a~ .. , ~ o ~ I o ~, h i i I u ~0 c~ ~ ~ ~D _~
~4 ~ I r,q :~: _ . u Il o ' ~ ~ c) i ! ~- ~ o "I
r~ j ~ h O
~) 1:: ~ ! c c ~ ~ r~ ~o r~ 0 1 o ~ I al ~ ~ c ~ ~: Ll ~ I
C) ~ .C U~ I ~ ~ r,o ~ ~ ~~ rJ rn i3 ~ I ~ . _ _ ~ ¦ ~ I o 3 ~ e ¦ i h ~ ¦
C) i~l r~
o O
I O h h ~ 1 ¦ r l ~2~
Procedures used for testing of samples in Table 1.
Bending streng~h: according to JACT Method SM-l Stick point: according to JACT Method C-l Tensile strength under elevated temperature:
according to JACT Method SM-10 Shake-out property:
Preparation of specimen:
¦¦ Coated sand is fed into an iron pipe of 29mm il in diameter and 150mm length. After 30 l minutes baking, it is covered with aluminum 10 ~I foil and further heated for 3 hours at 370C.
After cooling, the sand molded pipe is removed.
1ll Test method:
;~I The specimen is flogged by the impact arm of the apparatus illustrated in Fig. 1. Crumbled 15 1I sand is removed from the pipe after each l flogging. Weighing the residual molded sand of the specimen until it becomes zero, and the shake-out property is defined by the number of `I floggings required.
20 ~ Test apparatus:
In Fig. 1, A is a molded sand specimen and B is the arm which revolves around pivot C set at 30cm high. Said arm is at first set horizontally, and then allowed to drop so as 25 ~ to flog the specimen.
-l4-
Claims (20)
1. A resin coated sand for shell-molding foundry operations providing improved shake-out properties of molds prepared therefrom, comprising foundry aggregates coated with a phenolic resin containing an aromatic nitro compound, wherein the incorporating range of aromatic nitro compounds to 100 parts by weight phenolic resin is from about 0.2 to about 40 parts by weight.
2. A resin coated sand according to claim 1, wherein the aromatic nitro compound is selected from o-nitrophenol, p-nitrophenol, m-nitrophenol, 2,4-dinitrophenol, 2,5-dinitro-phenol, 2,6-dinitrophenol and dinitronaphthalene.
3. A resin coated sand according to claim 1, wherein the phenolic resin is a novolac phenolic resin.
4. A resin coated sand according to claim 1, wherein the phenolic resin is a resole phenolic resin.
5. A resin coated sand according to claim 1, wherein the phenolic resin is a mixture of novolac and resole phenolic resins.
6. A resin coated sand according to claim 2, wherein the phenolic resin additionally contains a lubricant.
7. A resin coated sand according to claim 3, 4 or 5, wherein the phenolic resin additionally contains a lubricant.
8. A method for producing resin coated sand for shell-molding foundry operations having improved shake-out properties of molds prepared therefrom comprising coating foundry aggregates with phenolic resin containing an aromatic nitro compound, wherein the incorporating range of aromatic nitro compounds to 100 parts by weight phenolic resin is from about 0.2 to about 40 parts by weight.
9. A method for producing resin coated sand according to claim 8, wherein the aromatic nitro compound is selected from o-nitrophenol, p-nitrophenol, m-nitrophenol, 2,4-dinitro-phenol, 2,5-dinitrophenol, 2,6-dinitrophenol or dinitro-naphthalene.
10. A method for producing resin coated sand according to claim 8, wherein the phenolic resin is a novolac phenolic resin.
11. A method for producing resin coated sand according to claim 9, wherein the phenolic resin is a novolac phenolic resin.
12. A method for producing resin coated sand according to claim 8, wherein the phenolic resin is a resole phenolic resin.
13. A method for producing resin coated sand according to claim 9, wherein the phenolic resin is a resole phenolic resin.
14. A method for producing resin coated sand according to claim 8, wherein the phenolic resin is a mixture of novolac and resole phenolic resins.
15. A method for producing resin coated sand according to claim 9, wherein the phenolic resin is a mixture of novolac and resole phenolic resins.
16. A method for producing resin coated sand according to claim 9, 10 or 11, wherein the phenolic resin contains additionally a lubricant.
17. A method for producing resin coated sand according to claim 12, 13 or 14, wherein the phenolic resin contains additionally a lubricant.
18. A method for producing resin coated sand according to claim 15 or 16, wherein the phenolic resin contains additionally a lubricant.
19. A resin coated sand for shell-molding foundry operations providing improved shake-out properties of molds prepared therefrom comprising foundry aggregates coated with a phenolic resin containing a lubricant and from 0.2 to 40 parts of an aromatic nitro compound per 100 parts of phenolic resins.
20. A method for producing resin coated sand for shell-molding foundry operations having improved shake-out properties of molds prepared therefrom, comprising coating foundry aggregates with a phenolic resin containing a lubricant and from 0.2 to 40 parts of an aromatic nitro compound per 100 parts of phenolic resin.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP120690/1982 | 1982-07-13 | ||
| JP12069082A JPS5913543A (en) | 1982-07-13 | 1982-07-13 | Composition of resin coated sand and its production |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1223778A true CA1223778A (en) | 1987-07-07 |
Family
ID=14792542
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000432252A Expired CA1223778A (en) | 1982-07-13 | 1983-07-12 | Resin coated sand composition and method of producing same |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5913543A (en) |
| CA (1) | CA1223778A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0496399U (en) * | 1991-01-29 | 1992-08-20 |
-
1982
- 1982-07-13 JP JP12069082A patent/JPS5913543A/en active Pending
-
1983
- 1983-07-12 CA CA000432252A patent/CA1223778A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5913543A (en) | 1984-01-24 |
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