CA1196450A - Phenolic resin binder for shell-molds and resin- coated sand obtained therefrom - Google Patents
Phenolic resin binder for shell-molds and resin- coated sand obtained therefromInfo
- Publication number
- CA1196450A CA1196450A CA000412590A CA412590A CA1196450A CA 1196450 A CA1196450 A CA 1196450A CA 000412590 A CA000412590 A CA 000412590A CA 412590 A CA412590 A CA 412590A CA 1196450 A CA1196450 A CA 1196450A
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- Prior art keywords
- catalyst
- formaldehyde
- phenolic resin
- resin
- resin binder
- 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.)
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Classifications
-
- 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
- B22C1/26—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 carbohydrates; of distillation residues therefrom
-
- 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
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Health & Medical Sciences (AREA)
- Molecular Biology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Mold Materials And Core Materials (AREA)
- Phenolic Resins Or Amino Resins (AREA)
Abstract
ABSTRACT
This invention relates to phenolic resin useful as binder in the preparation of foundry sand cores and molds.
The phenol component of the resin is reacted, under acidic conditions, with a sugar and following this reaction is sub-sequently reacted with a formaldehyde source under acidic conditions to form a novolac type phenolic, or under alkaline conditions to form a resole type phenolic. The invention also includes the process for preparing coated sand for use as foundry resin-coated sand in shell-molding operations.
This invention relates to phenolic resin useful as binder in the preparation of foundry sand cores and molds.
The phenol component of the resin is reacted, under acidic conditions, with a sugar and following this reaction is sub-sequently reacted with a formaldehyde source under acidic conditions to form a novolac type phenolic, or under alkaline conditions to form a resole type phenolic. The invention also includes the process for preparing coated sand for use as foundry resin-coated sand in shell-molding operations.
Description
I',ACKGROUI~D Ol: TIIE INVENTION
The present invention relates to an improved phenolic resin ~in~er and resin coated sand obtained therefrom to be used in a shell-molding process~ In conventional shell-molding operations, ~oundry sand is mixed or coated with a resin and placed in a mold to obtain the configuration desired, followed by a heating cycle to allow the resin to polymerize and bind the sand particle~ into a firm structure. After the 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 destroyed to a degree that will allow the casting to be removed ~nd cleaned of sand in an efficient manner~
Conventional resin coated sand compositions have been typically prepared by mixing heated sand with a phenolic resin to obtain a coated sand~ Catalysts are mixed with the sand prior to the placing of the resin coated sand into the mold. However, there is a drawback in the conventional phenolic binders when used in shell-molding operations, namely the shell molds often crack. This is caused by abrupt thermal expansion of the mold of resin-coated sand exposed to high temperatures at pouring.
In order to eliminate this problem, cushioning sub-stances are usuall~ incorporated into the resin binder or resin-coated sand, to enable the shell-molds to have a degree of flexibility as well as reducing thermal expansion. Materials known to be cushioning substances are bisphenol A, "Vinsol", petroleum resins and rosins. These materials lower the thermal expansion o~ molds and are partially effective in the prevention of cracks that occur at pouring. Howe~er, they also present un-wanted problems, such as the emission of disagreeable odors due A~9P~
o decomp~sLtion and evaporation of disassociation products and hindering the shake-out property.
It is an object of this invention to provide a binder formulation that will prevent cracks in the mold due to the thermal shock created by casting hot metal into the shell-mold.
I~ is a fur~her object of this invention to improve the shake-out proper~y of the sand grains by utilizing the resin coated sand of this invention.
SUMMARY OE' THE INVENTION
This invention relates to a phenolic resin binder and resin-coated sand obtained therefrom for sand shell-molding operations. The phenolic resin binder, disclosed herein, is prepared by reacting the phenol component with a sugar, such as cane or beet sugar or the syrupy residue of refined sugar, molasses. The reaction between the sugar and phenol is con-ducted in the presence of an acid catalyst. This product is then reacted with formaldehyde under basic or acidic conditions to form a resole or novolac phenolic resin. The phenolic resin is mixed with foundry sand and catalysts to form a resin-coated sand for use in shell-molding operations. The incorporation of a lubricant to the phenolic resin will improve the curing characteristics of the binder, and will assist in the preparation of the resin-sand mixture.
~ ~4'3~
DESCRIPTION OF THE PREE'ERRED EMBI~DIMENT
_ . __ _ After investigation to overcome the above mentioned drawbacks, the inventors hereof have found that both prevention of cracks in molds and improvement of shake-out property are attained by using resin-coated sand wherein foundry sand grains are coated with sugar-modified phenolic resins. A phenolic resin of the novolac type, that is, one obtained by reacting sugars and phenols with an acid catalyst, and successively reacting the product with formaldehyde with an acidic catalyst; or a resole type resin obtained by reacting sugars and phenols with an acid catalyst, and successively reacting the product with formaldehyde with a basic catalyst may be used.
Generally speaking, the major portion of commerclal sugar is saccharose, which is called cane or beet sugar according to its source, graded as syrup-containing and syrup-free at stages of processing, as crude and refined, and at refining steps as white, brown and black according to its color, or as powder, cube and crystal according to its available form. Also molasses is the syrupy residue of refined sugar. Any of said grades there-of is usable in the present invention.
~ hen phenols and sugars are mixed and heated with an acid catalyst, they react with each other and form a chemical bond. ~hPy scarcely react in a neutral state or with a basic catalyst. Acid catalysts used for the reaction between sugars and phenols, or successively with formaldehyde are inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, boric acid and phosphoric acid, and organic acids such as para-toluene sulfonic acid, benzene sulfonic acid, xylene sulfonic acid, oxalic acid, maleic acid, formic acid, acetic acid and succinic acid.
After reacting su~ars and phenols with an acidic catalyst , he reaction mixture is :uccessively reacted in acidic ccndition 3~
with formaldehyde, followed by dehydration under vacuum producing a s~gar-modified novolac type phenolic resin of reddish-brown to brownish-black in color. This resln, resembles ordinary novolac type phenolic resin obtained by reacting phenols and formaldehyae ~ith ar. acid catalyst and cures by heating with addition of a formaldehyde donor such as hexamethylenetetramine or para-formaldehyde forming a three-dimensional cross-linked structure.
After reacting sugars and phenols with an acid catalyst, the reaction mixture is successively reacted by adding a basic catalyst thereto, such as sodium hydroxide, potassium hydroxide, aqueous ammonia, aminesl calcium hydroxide, magnesium hydroxide, or quick lime, with formaldehyde,followed by dehydration under vacuum to produce a sugar-modified resole type phenolic resin of yellowish-brown to brownish-black in color. This resin, resembles ordinary resole type phenolic resin obtained by reacting phenols and formaldehyde with a basic catalyst and cures by heating forming a three-dimensional cross-linked structure~
In preparing sugar-modified phenolic resins, phenols herein are phenol, cresol, xylenol, catechol, resorcine, and a mixture thereof, however, a portion thereof may be substituted with hydroquinone, aniline, urea, melamine, cashew nut shell oil, etc. Formaldehyde herein is selected from aldehyde donors such as formalin, parafo~naldehyde, and trioxane.
The ratio of sugar to phenol should range from 70-10 to 30-90 parts, by weight. When khe sugar is less than 10 parts relative to the phenol, there is present insufficient sugar modified phenol to prevent crac~ing of the mold and the shake out property of the resin is not improved. ~hen the sugar is greater than 70 parts relative to the phenol, the mechanical strength of l~C3~45~
the shell molds is lowered due to a chemically loose three-dimensional structure of the cured ~esin.
In preparing a suitable novolac type phenolic resin, the molar ratio o~ formaldehyde to 1 mole of phenols is 0.3 - 0.9.
When said ratio is less than 0.3, the chemical three-dimensional structure after curing said resin binder is loose, and it results in lowering the physical properties of shell-molds. When said ratio is more than 0.9, mold cracks are inevitable at pouring and the resin binder thus obtained is ineffective for a better shake-out property of shell-molds.
In preparing a resole type phenolic resin, a suitable resin is obtained by selecting the molar ratio of formaldehyde to 1 mole of phenols at 1 - 3. When said ratio is less than 1, it results in lowering the rate of cure of the resin binder, and a chemically loose three-dimensional structure after curing results, thus it leads to lowering the physical properties of shel]-molds.
When said ratio is more than 3, mold cracks are inevitable at pouring, and no improvement in shake-out property can be obtained.
A preferable embodiment o~ the present invention is to add lubricants into phenolic resins. Said lubricants are not only useful in improving shell properties but also prevent the powder resin from agglomerating or improve the curing characteristics of xesin binders. Ordinary lubricants are usable in the present invention, however, preferable are ethylene bis-stearic amide, methylene bis-stearic amide, oxy-stearic amide, and methyol stearic amide.
Methods for producing coated sand adopted in the present invention may be any of the commercial hot coatiny, semi-hot coating, cold coating, and powder solv nt coating processes. The respective embodiments are as follo~s.
_5_ (1~ ~t coating process: A method for coating hot sand (130 - 140C) ~y adding a solid resin thereto.
The present invention relates to an improved phenolic resin ~in~er and resin coated sand obtained therefrom to be used in a shell-molding process~ In conventional shell-molding operations, ~oundry sand is mixed or coated with a resin and placed in a mold to obtain the configuration desired, followed by a heating cycle to allow the resin to polymerize and bind the sand particle~ into a firm structure. After the 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 destroyed to a degree that will allow the casting to be removed ~nd cleaned of sand in an efficient manner~
Conventional resin coated sand compositions have been typically prepared by mixing heated sand with a phenolic resin to obtain a coated sand~ Catalysts are mixed with the sand prior to the placing of the resin coated sand into the mold. However, there is a drawback in the conventional phenolic binders when used in shell-molding operations, namely the shell molds often crack. This is caused by abrupt thermal expansion of the mold of resin-coated sand exposed to high temperatures at pouring.
In order to eliminate this problem, cushioning sub-stances are usuall~ incorporated into the resin binder or resin-coated sand, to enable the shell-molds to have a degree of flexibility as well as reducing thermal expansion. Materials known to be cushioning substances are bisphenol A, "Vinsol", petroleum resins and rosins. These materials lower the thermal expansion o~ molds and are partially effective in the prevention of cracks that occur at pouring. Howe~er, they also present un-wanted problems, such as the emission of disagreeable odors due A~9P~
o decomp~sLtion and evaporation of disassociation products and hindering the shake-out property.
It is an object of this invention to provide a binder formulation that will prevent cracks in the mold due to the thermal shock created by casting hot metal into the shell-mold.
I~ is a fur~her object of this invention to improve the shake-out proper~y of the sand grains by utilizing the resin coated sand of this invention.
SUMMARY OE' THE INVENTION
This invention relates to a phenolic resin binder and resin-coated sand obtained therefrom for sand shell-molding operations. The phenolic resin binder, disclosed herein, is prepared by reacting the phenol component with a sugar, such as cane or beet sugar or the syrupy residue of refined sugar, molasses. The reaction between the sugar and phenol is con-ducted in the presence of an acid catalyst. This product is then reacted with formaldehyde under basic or acidic conditions to form a resole or novolac phenolic resin. The phenolic resin is mixed with foundry sand and catalysts to form a resin-coated sand for use in shell-molding operations. The incorporation of a lubricant to the phenolic resin will improve the curing characteristics of the binder, and will assist in the preparation of the resin-sand mixture.
~ ~4'3~
DESCRIPTION OF THE PREE'ERRED EMBI~DIMENT
_ . __ _ After investigation to overcome the above mentioned drawbacks, the inventors hereof have found that both prevention of cracks in molds and improvement of shake-out property are attained by using resin-coated sand wherein foundry sand grains are coated with sugar-modified phenolic resins. A phenolic resin of the novolac type, that is, one obtained by reacting sugars and phenols with an acid catalyst, and successively reacting the product with formaldehyde with an acidic catalyst; or a resole type resin obtained by reacting sugars and phenols with an acid catalyst, and successively reacting the product with formaldehyde with a basic catalyst may be used.
Generally speaking, the major portion of commerclal sugar is saccharose, which is called cane or beet sugar according to its source, graded as syrup-containing and syrup-free at stages of processing, as crude and refined, and at refining steps as white, brown and black according to its color, or as powder, cube and crystal according to its available form. Also molasses is the syrupy residue of refined sugar. Any of said grades there-of is usable in the present invention.
~ hen phenols and sugars are mixed and heated with an acid catalyst, they react with each other and form a chemical bond. ~hPy scarcely react in a neutral state or with a basic catalyst. Acid catalysts used for the reaction between sugars and phenols, or successively with formaldehyde are inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, boric acid and phosphoric acid, and organic acids such as para-toluene sulfonic acid, benzene sulfonic acid, xylene sulfonic acid, oxalic acid, maleic acid, formic acid, acetic acid and succinic acid.
After reacting su~ars and phenols with an acidic catalyst , he reaction mixture is :uccessively reacted in acidic ccndition 3~
with formaldehyde, followed by dehydration under vacuum producing a s~gar-modified novolac type phenolic resin of reddish-brown to brownish-black in color. This resln, resembles ordinary novolac type phenolic resin obtained by reacting phenols and formaldehyae ~ith ar. acid catalyst and cures by heating with addition of a formaldehyde donor such as hexamethylenetetramine or para-formaldehyde forming a three-dimensional cross-linked structure.
After reacting sugars and phenols with an acid catalyst, the reaction mixture is successively reacted by adding a basic catalyst thereto, such as sodium hydroxide, potassium hydroxide, aqueous ammonia, aminesl calcium hydroxide, magnesium hydroxide, or quick lime, with formaldehyde,followed by dehydration under vacuum to produce a sugar-modified resole type phenolic resin of yellowish-brown to brownish-black in color. This resin, resembles ordinary resole type phenolic resin obtained by reacting phenols and formaldehyde with a basic catalyst and cures by heating forming a three-dimensional cross-linked structure~
In preparing sugar-modified phenolic resins, phenols herein are phenol, cresol, xylenol, catechol, resorcine, and a mixture thereof, however, a portion thereof may be substituted with hydroquinone, aniline, urea, melamine, cashew nut shell oil, etc. Formaldehyde herein is selected from aldehyde donors such as formalin, parafo~naldehyde, and trioxane.
The ratio of sugar to phenol should range from 70-10 to 30-90 parts, by weight. When khe sugar is less than 10 parts relative to the phenol, there is present insufficient sugar modified phenol to prevent crac~ing of the mold and the shake out property of the resin is not improved. ~hen the sugar is greater than 70 parts relative to the phenol, the mechanical strength of l~C3~45~
the shell molds is lowered due to a chemically loose three-dimensional structure of the cured ~esin.
In preparing a suitable novolac type phenolic resin, the molar ratio o~ formaldehyde to 1 mole of phenols is 0.3 - 0.9.
When said ratio is less than 0.3, the chemical three-dimensional structure after curing said resin binder is loose, and it results in lowering the physical properties of shell-molds. When said ratio is more than 0.9, mold cracks are inevitable at pouring and the resin binder thus obtained is ineffective for a better shake-out property of shell-molds.
In preparing a resole type phenolic resin, a suitable resin is obtained by selecting the molar ratio of formaldehyde to 1 mole of phenols at 1 - 3. When said ratio is less than 1, it results in lowering the rate of cure of the resin binder, and a chemically loose three-dimensional structure after curing results, thus it leads to lowering the physical properties of shel]-molds.
When said ratio is more than 3, mold cracks are inevitable at pouring, and no improvement in shake-out property can be obtained.
A preferable embodiment o~ the present invention is to add lubricants into phenolic resins. Said lubricants are not only useful in improving shell properties but also prevent the powder resin from agglomerating or improve the curing characteristics of xesin binders. Ordinary lubricants are usable in the present invention, however, preferable are ethylene bis-stearic amide, methylene bis-stearic amide, oxy-stearic amide, and methyol stearic amide.
Methods for producing coated sand adopted in the present invention may be any of the commercial hot coatiny, semi-hot coating, cold coating, and powder solv nt coating processes. The respective embodiments are as follo~s.
_5_ (1~ ~t coating process: A method for coating hot sand (130 - 140C) ~y adding a solid resin thereto.
(2) Cold coating process: A method for coating sand with a resin dissolved in a solvent such as methanol.
(3) Semi-hot coating process: A method fox coating hot sand (80 - 100C) by adding said liquid resin thereto.
~ 4~ Powder-sol~ent process: ~ method for coating sand by adding a solvent such as methanol, after adding a powdered resin to the sand.
Among them, the hot coating process is more preferable in caxrying out the present invention.
The inventors hereof will explain the present invention with the following nonlimitative Examples and Comparative Examples wherein both "parts" and "percent" indicate "part by weight" and "percent by weight", respectively.
To a reaction kettle with a reflux cooler and stirrer, 1000 parts of phenol, 429 parts of sugar and 7 parts of con-centrated sulfuric acid were charged, and the temperature of the kettle was gradually ele~ated. After reacting sugar with phenol at 100C for 180 ~sinutes, the pH value of the reaction mixture was found to be 0~8. To the reaction mixture, 431 parts of 37~
formalin was added and reacted for additional 120 minutes at 96C.
Successively it was neutralized by adding 9 parts of slaked lime thereto. After adding 10 parts of methylene bis-stearic amide thereto with mixing~ followed by dehydration under vacuum, 1320 parts of a sugar-modified nvvolac type phenolic resin were ob-tained.
EXAMPLE_2 To a reaction kettle with a reflux cooler and a stirrer, 1000 parts of phenol,1000 parts of sugar and 15 parts of para-toluene sulfonic acid were charged and the temperature of the kettle was gradually elevated. After reacting sugar with phenol at 100C for ~40 minutes, the pH value of the reaction mixture was found to be 1 2. To the reaction mixture, 518 parts of 3~%
formalin were added and reacted for additional 90 minutes at 96C.
Successively, 80 parts of 50% sodium hydroxide solution, 200 parts of 28~ a~ueous ammonia and 1206 parts of 37% formalin werP added thereto, then, reacted for 30 minutes at 96C. After adding 15 parts of ethylene bis-stearic amide thereto with mixing, followed by dehydration under Yacuum, 2350 parts of a sugar modified resole type phenolic resin were ohtained.
To a reaction kettle with a reflux cooler and a stirrer, 900 parts of phenol, 100 parts of cashew nut shell oil, 429 parts of sugar and 10 parts of concentrated sulfuric acid were charged, and the temperature of the kettle was gradually elevated. After reacting sugar, phenol and cashew nut shell oil for 240 minutes at lOO~C, the pH value was ound to be 0.5. To the reaction mixture, 431 parts of 37% formalin were added and reacted for additional 120 minutes at 96C. Successively it was neutralized by adding 12 parts o~ slaXed lime thereto. After adding 10 parts of methylene bis-stearic amide thereto with mixing, followed by dehydra~iDn under ~acuum, 1350 parts of a sugar-modified novolac type phenolic resin were obtained.
EX~MPLE 4 To a reaction kett1e with a reflux cooler and a stirrer, ~ ~ 51~
50 par~s of phenol, 250 parts of meta-cresol, 429 parts of sugar and 6 par~s of concentrated sulfuric acid were charged, and the temperature of the kettle was gradually elevated. After reacting sugar,phenol and metal-cresol, the pH value was found to be 0.9.
To the reaction mixture, 431 parts of 37~ formalin were added and reacted for additional 90 minutes at 96%C. Successively it was neutralized by adding 8 parts of slaked lime. After adding 10 parts of methylene bis-stearic amide thereto with mixing, followed by dehydration under vacuum, 1330 parts of a sugar-modified novolac type phenolic resin were obtained.
COMPARATIVE EXAMPLE I
To a reaction kettle with a reflux cooler and a stirrer, 1000 parts of phenol, 650 parts of 47% formalin and 10 parts of oxalic acid were charged, and the temperature of the kettle was gradually elevated. After the tempexature reached 96C, and 120 minutes' reaction thexeafter, 10 parts of ethylene bis-stearic amide was added thereto with mixing, followed by dehydration under vacuum, 970 parts of a novolac type phenolic resin were obtained.
COMPARATIVE EX~MPLE II
To a reaction kettle with a reflux cooler and a stirrer, 1000 parts of phenol, 1553 parts of 37% foxmalin, 60 parts of 50%
sodium hydroxide solution, and 160 parts of 28% aqueous ammonia were charged, and the temperature of the kettle was gradually eleva~ed. After the temperat~re reached 96C, and 30 minutes reaction thereafter, 40 parts of ethylene bis-stearic amide was added thereto with mixing, followed by dehydration under vacuum, 1060 parts of a resole type phenolic resin were obtained.
Table I indicates the characteristics of the four examples of sugar-modified phenolic resins and two comparative x~nple~ of non sugar-m~dified phenolic resins.
TABLE I
Reaction Conditions and ~omparative Resin Properties Examples Examples ...... , ~ ~
Weight proportion: 0 43 1 0.43 0.43 0 0 Sugars/Phenols _ _ Molar ratio:
Formaldehyde/Phenols 0.5 2 0.54 0.5~ 0.75 1.8 Melting point (C) 83 80 81 ~ 84 80 _ 78 Free phenol content ~ 3.7 4 1 3.2 3.5 5.5 5 9 The resin prepared in Examples 1-4 and Comparative Examples I and II were coated onto foundry sand and subjected to testing.
After heating to 130 ~ 140~C, 7000 parts of Sanei No. ~
shell sand was charged into a whirl-mixer and 210 pa~ts of sugar-modified novolac type phenolic resin obtained according to Example 1 was added thereto. After mixing for 30 seconds, 30 part s of hexamethylenetetramine dissolved in 80 parts of water was added thereto. The mixture was further mixed until it crumbled.
7 parts of calcium stearate was added thereto, followed by 30 seconds mixing, the mixture was discharged and aerated to obtain the resin-coated sand.
The proc~dure ~f Ex~mple 5 was followed except the sugar~
modified resole type phenolic resin obtained according to Example 2 was substituted, and the hexamethylenete~ramine was _g_ I
omitted to produce ~he resin-coated sand.
EXAMPX.E ?
The procedure of Example 5 was followed except the sugar-modified novolac resin prepared according to Example 3 was substituted, and resin coated sand was produced.
EXAMP~E 8 The procedure of Example 5 was followed except the sugar-modified novolac resin prepared according to Example 4 was substituted to produce the resin coated sand.
The procedure of Example 5 was followed except the novolac resin prepared according to Comparati~e Example I
was substituted to produce the resin coated sand.
- COMPARATIVE EXAMæLE IV
The procedure of Example 6 was followed except the resole resin prepared according to Comparative Example II
was substituted to produce the coated sand.
Table Il indicates the characteristics of the resin coated sand and the shake out property of shell-molds therefrom.
~ ~ 5~
Cl~ ~O~r u~
~ ~ U ,~ ~ U~ ~ ~ o .~ U) ~-~
al _ 5; ~ ~ ~ ,~ oo ~r ~ ~ ~ c u~ ~ r~ a~ ,~
~ X H C ~ rl U ~ ~D
c~ ~ r o~
a~ ~ ~ In r~ ,i c:
__ _ In ~ r o a~
~ ~ Lr) î~ ~ O
I`~ C I` ~1 ~ __ ~ O .
O CO ~ r-l 1` a~
1~ r' ,1 ~ u~ co O O
~3 ~Dc ~D N
~ ~ _ H ~7 el~ ~D t~ co H 11~ co ~`1 Ll'~ 1-- ~i O r~
~ ~ I~ ~ ~
~ _ _ ., E~ ~ ~ ~ ~) ~
o a) ~ ~ ,~
~ U~ ~
K o ~ o d _ ~ ~ ~D, X
-~ ~ ~ ~
o ~ ~ ~D S~ E Q~ .
-~ Ul U~ s ~C
O ~ ~ ~^ .
P~ tl~ a) :~ .~ dP O^
a~ ~ ~ ~_ I ~n .~ ~1 ~ a) t) ~ ~ ~
o ~ ~n a) Q-~ ~ O ~ ~3 ,~ ~ .c~ k ~ n5-r Gl a) ~ O K Q ~a rt::
u~ m E~ ~ ~_ ~: ~ ~"_ Test Methods:
Bending strength~ according to JACT Method SM-l stick point. ~cc~r~ing to JACT Method C-l Tensile strength under elevated temperature:
according to JACT Method SM-10 Abrupt thermal expansion rate:
according to JACT Method SM-7 at 1000C
Shake-out property:
Preparation of specimen:
Coated sand is fed into an iron pipe of 29mm in diameter and 150mm in length. After 30 minutes baking, it is covered with aluminium foil and ~urther heated for 3 hours at 370C. After cooling, the sand molded pipe is taken out.
Test method:
The specimen is struck by the impact arm of the apparatus illustrated in Fig. 1. Crumbled sand is removed from the pipe after each flogginy~
Weighing the residual molded sand of the specimen until it becomes zero, the shake-out property is defined by the number of floggings required.
Test apparatus:
A molded sand specimen is disposed below an arm which revolves around a pivot set at 30cm high. Said arm is at first set horizontally, and then allowed to drop so as to flog said specimen.
~ 4~ Powder-sol~ent process: ~ method for coating sand by adding a solvent such as methanol, after adding a powdered resin to the sand.
Among them, the hot coating process is more preferable in caxrying out the present invention.
The inventors hereof will explain the present invention with the following nonlimitative Examples and Comparative Examples wherein both "parts" and "percent" indicate "part by weight" and "percent by weight", respectively.
To a reaction kettle with a reflux cooler and stirrer, 1000 parts of phenol, 429 parts of sugar and 7 parts of con-centrated sulfuric acid were charged, and the temperature of the kettle was gradually ele~ated. After reacting sugar with phenol at 100C for 180 ~sinutes, the pH value of the reaction mixture was found to be 0~8. To the reaction mixture, 431 parts of 37~
formalin was added and reacted for additional 120 minutes at 96C.
Successively it was neutralized by adding 9 parts of slaked lime thereto. After adding 10 parts of methylene bis-stearic amide thereto with mixing~ followed by dehydration under vacuum, 1320 parts of a sugar-modified nvvolac type phenolic resin were ob-tained.
EXAMPLE_2 To a reaction kettle with a reflux cooler and a stirrer, 1000 parts of phenol,1000 parts of sugar and 15 parts of para-toluene sulfonic acid were charged and the temperature of the kettle was gradually elevated. After reacting sugar with phenol at 100C for ~40 minutes, the pH value of the reaction mixture was found to be 1 2. To the reaction mixture, 518 parts of 3~%
formalin were added and reacted for additional 90 minutes at 96C.
Successively, 80 parts of 50% sodium hydroxide solution, 200 parts of 28~ a~ueous ammonia and 1206 parts of 37% formalin werP added thereto, then, reacted for 30 minutes at 96C. After adding 15 parts of ethylene bis-stearic amide thereto with mixing, followed by dehydration under Yacuum, 2350 parts of a sugar modified resole type phenolic resin were ohtained.
To a reaction kettle with a reflux cooler and a stirrer, 900 parts of phenol, 100 parts of cashew nut shell oil, 429 parts of sugar and 10 parts of concentrated sulfuric acid were charged, and the temperature of the kettle was gradually elevated. After reacting sugar, phenol and cashew nut shell oil for 240 minutes at lOO~C, the pH value was ound to be 0.5. To the reaction mixture, 431 parts of 37% formalin were added and reacted for additional 120 minutes at 96C. Successively it was neutralized by adding 12 parts o~ slaXed lime thereto. After adding 10 parts of methylene bis-stearic amide thereto with mixing, followed by dehydra~iDn under ~acuum, 1350 parts of a sugar-modified novolac type phenolic resin were obtained.
EX~MPLE 4 To a reaction kett1e with a reflux cooler and a stirrer, ~ ~ 51~
50 par~s of phenol, 250 parts of meta-cresol, 429 parts of sugar and 6 par~s of concentrated sulfuric acid were charged, and the temperature of the kettle was gradually elevated. After reacting sugar,phenol and metal-cresol, the pH value was found to be 0.9.
To the reaction mixture, 431 parts of 37~ formalin were added and reacted for additional 90 minutes at 96%C. Successively it was neutralized by adding 8 parts of slaked lime. After adding 10 parts of methylene bis-stearic amide thereto with mixing, followed by dehydration under vacuum, 1330 parts of a sugar-modified novolac type phenolic resin were obtained.
COMPARATIVE EXAMPLE I
To a reaction kettle with a reflux cooler and a stirrer, 1000 parts of phenol, 650 parts of 47% formalin and 10 parts of oxalic acid were charged, and the temperature of the kettle was gradually elevated. After the tempexature reached 96C, and 120 minutes' reaction thexeafter, 10 parts of ethylene bis-stearic amide was added thereto with mixing, followed by dehydration under vacuum, 970 parts of a novolac type phenolic resin were obtained.
COMPARATIVE EX~MPLE II
To a reaction kettle with a reflux cooler and a stirrer, 1000 parts of phenol, 1553 parts of 37% foxmalin, 60 parts of 50%
sodium hydroxide solution, and 160 parts of 28% aqueous ammonia were charged, and the temperature of the kettle was gradually eleva~ed. After the temperat~re reached 96C, and 30 minutes reaction thereafter, 40 parts of ethylene bis-stearic amide was added thereto with mixing, followed by dehydration under vacuum, 1060 parts of a resole type phenolic resin were obtained.
Table I indicates the characteristics of the four examples of sugar-modified phenolic resins and two comparative x~nple~ of non sugar-m~dified phenolic resins.
TABLE I
Reaction Conditions and ~omparative Resin Properties Examples Examples ...... , ~ ~
Weight proportion: 0 43 1 0.43 0.43 0 0 Sugars/Phenols _ _ Molar ratio:
Formaldehyde/Phenols 0.5 2 0.54 0.5~ 0.75 1.8 Melting point (C) 83 80 81 ~ 84 80 _ 78 Free phenol content ~ 3.7 4 1 3.2 3.5 5.5 5 9 The resin prepared in Examples 1-4 and Comparative Examples I and II were coated onto foundry sand and subjected to testing.
After heating to 130 ~ 140~C, 7000 parts of Sanei No. ~
shell sand was charged into a whirl-mixer and 210 pa~ts of sugar-modified novolac type phenolic resin obtained according to Example 1 was added thereto. After mixing for 30 seconds, 30 part s of hexamethylenetetramine dissolved in 80 parts of water was added thereto. The mixture was further mixed until it crumbled.
7 parts of calcium stearate was added thereto, followed by 30 seconds mixing, the mixture was discharged and aerated to obtain the resin-coated sand.
The proc~dure ~f Ex~mple 5 was followed except the sugar~
modified resole type phenolic resin obtained according to Example 2 was substituted, and the hexamethylenete~ramine was _g_ I
omitted to produce ~he resin-coated sand.
EXAMPX.E ?
The procedure of Example 5 was followed except the sugar-modified novolac resin prepared according to Example 3 was substituted, and resin coated sand was produced.
EXAMP~E 8 The procedure of Example 5 was followed except the sugar-modified novolac resin prepared according to Example 4 was substituted to produce the resin coated sand.
The procedure of Example 5 was followed except the novolac resin prepared according to Comparati~e Example I
was substituted to produce the resin coated sand.
- COMPARATIVE EXAMæLE IV
The procedure of Example 6 was followed except the resole resin prepared according to Comparative Example II
was substituted to produce the coated sand.
Table Il indicates the characteristics of the resin coated sand and the shake out property of shell-molds therefrom.
~ ~ 5~
Cl~ ~O~r u~
~ ~ U ,~ ~ U~ ~ ~ o .~ U) ~-~
al _ 5; ~ ~ ~ ,~ oo ~r ~ ~ ~ c u~ ~ r~ a~ ,~
~ X H C ~ rl U ~ ~D
c~ ~ r o~
a~ ~ ~ In r~ ,i c:
__ _ In ~ r o a~
~ ~ Lr) î~ ~ O
I`~ C I` ~1 ~ __ ~ O .
O CO ~ r-l 1` a~
1~ r' ,1 ~ u~ co O O
~3 ~Dc ~D N
~ ~ _ H ~7 el~ ~D t~ co H 11~ co ~`1 Ll'~ 1-- ~i O r~
~ ~ I~ ~ ~
~ _ _ ., E~ ~ ~ ~ ~) ~
o a) ~ ~ ,~
~ U~ ~
K o ~ o d _ ~ ~ ~D, X
-~ ~ ~ ~
o ~ ~ ~D S~ E Q~ .
-~ Ul U~ s ~C
O ~ ~ ~^ .
P~ tl~ a) :~ .~ dP O^
a~ ~ ~ ~_ I ~n .~ ~1 ~ a) t) ~ ~ ~
o ~ ~n a) Q-~ ~ O ~ ~3 ,~ ~ .c~ k ~ n5-r Gl a) ~ O K Q ~a rt::
u~ m E~ ~ ~_ ~: ~ ~"_ Test Methods:
Bending strength~ according to JACT Method SM-l stick point. ~cc~r~ing to JACT Method C-l Tensile strength under elevated temperature:
according to JACT Method SM-10 Abrupt thermal expansion rate:
according to JACT Method SM-7 at 1000C
Shake-out property:
Preparation of specimen:
Coated sand is fed into an iron pipe of 29mm in diameter and 150mm in length. After 30 minutes baking, it is covered with aluminium foil and ~urther heated for 3 hours at 370C. After cooling, the sand molded pipe is taken out.
Test method:
The specimen is struck by the impact arm of the apparatus illustrated in Fig. 1. Crumbled sand is removed from the pipe after each flogginy~
Weighing the residual molded sand of the specimen until it becomes zero, the shake-out property is defined by the number of floggings required.
Test apparatus:
A molded sand specimen is disposed below an arm which revolves around a pivot set at 30cm high. Said arm is at first set horizontally, and then allowed to drop so as to flog said specimen.
Claims (16)
1. A phenolic resin binder for the shell-molding pro-cess comprising reacting sugars with phenols in the presence of an acid catalyst and, thereafter reacting with formaldehyde in the presence of a catalyst.
2. A phenolic resin binder according to claim 1, wherein said binder contains a lubricant.
3. A phenolic resin binder according to claim 1, wherein the proportion of sugar to phenol is about 70 - 10 to about 30 -90 parts by weight.
4. A phenolic resin binder according to claim 3, wherein said binder contains a lubricant.
5. A phenolic resin binder according to claim 1, 2 or 3, wherein said catalyst for formaldehyde-sugar modified phenol reaction is an acid catalyst.
6. A phenolic resin binder according to claim 1, 2 or 3, wherein said catalyst for formaldehyde-sugar modified phenol reaction is an acid catalyst, and the molar ratio of formaldehyde to phenol is about 0.3 - 0.9 to 1.
7. A phenolic resin binder according to claim 1, 2 or 3, wherein said catalyst for the formaldehyde-sugar modified phenol reaction is a basic catalyst.
8. A phenolic resin binder according to claim 1, 2 or 3, wherein said catalyst for the formaldehyde-sugar modified phenol reaction is a basic catalyst, and the molar ratio of formaldehyde is about 1 - 3 to 1 mole of phenol.
9. A phenolic resin binder according to claim 4, wherein said catalyst for formaldehyde-sugar modified phenol reaction is an acid catalyst.
10. A phenolic resin binder according to claim 9, wherein the molar ratio of formaldehyde to phenol is about 0.3 - 0.9 to 1.
11. A phenolic resin binder according to claim 4, wherein said catalyst for the formaldehyde-sugar modified phenol reaction is a basic catalyst.
12. A phenolic resin binder according to claim 11, wherein the molar ratio of formaldehyde is about 1 - 3 to 1 mole of phenol.
13. Resin coated sand for shell molding processes comprising foundry sand grains coated with a resin obtained by reacting sugars with phenols in the presence of an acid catalyst followed by reacting with formaldehyde in the presence of a catalyst.
14. Resin coated sand according to claim 13, wherein the catalyst for the formaldehyde-sugar modified phenol reaction is an acid catalyst.
15. Resin coated sand according to claim 13, wherein the catalyst for the formaldehyde-sugar modified phenol reaction is a basic catalyst.
16. Resin coated sand according to claim 13, 14 or 15, wherein said resin contains a lubricant.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP15383481A JPS5855146A (en) | 1981-09-30 | 1981-09-30 | Phenolic resin binder for shell mold and resin coated sand produced by using said binder |
| JP153,834/1981 | 1981-09-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1196450A true CA1196450A (en) | 1985-11-05 |
Family
ID=15571106
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000412590A Expired CA1196450A (en) | 1981-09-30 | 1982-09-30 | Phenolic resin binder for shell-molds and resin- coated sand obtained therefrom |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5855146A (en) |
| CA (1) | CA1196450A (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6316830A (en) * | 1986-07-09 | 1988-01-23 | Gunei Kagaku Kogyo Kk | Resin covered sand for shell mold |
| EP0961813B1 (en) | 1997-02-20 | 2004-04-21 | Kronospan Technical Co. Ltd. | Adhesive composition and its use |
| WO1998037148A2 (en) * | 1997-02-20 | 1998-08-27 | Kronospan Gmbh | Adhesive composition |
| WO1998037147A2 (en) * | 1997-02-20 | 1998-08-27 | Kronospan Gmbh | Adhesive composition and its use |
| JP4963579B2 (en) * | 2006-08-28 | 2012-06-27 | リグナイト株式会社 | Polysaccharide-modified phenolic resin, production method of polysaccharide-modified phenolic resin, resin-coated sand, polysaccharide-modified phenolic resin carbonized material, conductive resin composition, carbon material for electrode, electrode for secondary battery, electric double layer capacitor polarizability electrode |
| JP5002792B2 (en) * | 2006-08-28 | 2012-08-15 | リグナイト株式会社 | Polysaccharide-modified phenolic resin, production method of polysaccharide-modified phenolic resin, resin-coated sand, polysaccharide-modified phenolic resin carbonized material, conductive resin composition, carbon material for electrode, electrode for secondary battery, electric double layer capacitor polarizability electrode |
| JP5478048B2 (en) * | 2008-10-09 | 2014-04-23 | 群栄化学工業株式会社 | Phenolic resin |
| WO2011030795A1 (en) * | 2009-09-10 | 2011-03-17 | リグナイト株式会社 | Binder-coated refractory, casting mold and method for producing casting mold |
| JP5437053B2 (en) * | 2009-12-24 | 2014-03-12 | 群栄化学工業株式会社 | Thermosetting molding material and molded product |
| JP5731758B2 (en) * | 2010-04-20 | 2015-06-10 | 群栄化学工業株式会社 | Biomass phenol resin, production method thereof, thermosetting material |
| JP6694711B2 (en) * | 2015-12-28 | 2020-05-20 | 株式会社ブリヂストン | Phenolic resin, method for producing phenolic resin, rubber composition and tire |
| WO2017187907A1 (en) * | 2016-04-25 | 2017-11-02 | 株式会社ブリヂストン | Phenolic resin to be blended with rubber, rubber composition, and tire |
-
1981
- 1981-09-30 JP JP15383481A patent/JPS5855146A/en active Pending
-
1982
- 1982-09-30 CA CA000412590A patent/CA1196450A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5855146A (en) | 1983-04-01 |
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