CA1119334A - Novalac lubricant-containing resole-sand composition - Google Patents
Novalac lubricant-containing resole-sand compositionInfo
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- CA1119334A CA1119334A CA000294627A CA294627A CA1119334A CA 1119334 A CA1119334 A CA 1119334A CA 000294627 A CA000294627 A CA 000294627A CA 294627 A CA294627 A CA 294627A CA 1119334 A CA1119334 A CA 1119334A
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- resin
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- parts
- resole
- weight
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Abstract
Abstract This invention related to resin-coated sand compositions useful in the preparation of foundry sand cores and molds comprising sand, a solid novalac resin, a lubricant-containing solid resole resin, and optionally, hexamethylenetramine in an amount of up to about 5 parts by weight based on 100 parts by weight of the total amount of resin.
Description
Background of the Invention This inYention is directed to resin-coated sand compositions and a process for the preparation thereof, and more particularly, to a process for producing resin-coated sand compositions substantially free of nitrogen by the dry hot coating method. The compositions thus prepared are suitable for manufacturing foundry sand cores and ~olds.
Conventional resin-coated sand compositions have been typically prepared by the dry hot coating method by mixing heated sand particles with a novolac phenolic resin (hereinafter referred to as a novolac resin) in the form of an agitated aqueous solution, adding hexamethylenetetramine (hereinafter referred to as hexamine) as a hardening agent, in an amount of 10 to 15 parts by we;ght with respect to 100 parts by weight of resin, and further adding calcium stearate.
Such resin-coated sand compositions produced with novolac resins and lS hexamine exhibit fast curing and excellent flow, but are also often as-sociated with certain drawbacks such as pollution problems and defects in the cast products, such as pinholes or blow holes resulting from the presence of nitrogen compounds, such as ammonia or formaldehyde, generated - by the pyrolysis of hexamine when the resin-coated sand compositions are ~ used in iron or steel casting or when forming molds.
In order to avoid such problems, various attempts have been made to . employ a shell molding resin with a very low nitrogen content when using dry hot coating methods. A representative attempt in this direction is the use of a sotid resole phenolic resin obtained with an ammonia catalyst (hereinafter referred to as a solid ammonia resole resin).
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This method is, however, associated with certain drawbacks such as slower hardening as compared to novolac resins cured with hexamine, and unsatisfactory flow (insufficient hot flow) resulting from premature local curing before the sand particles become well-coated in the course of mulling.
As a result, the cured articles frequently exhibit significantly lower physical strength than those obtained with a novolac resin and hexamine, and, therefore, this method has not been extensively employed in practice.
A method has also been proposed for controlling the degree o~ reaction of a solid ammonia resole resin in the earlier stages of reaction in order to accelerate the hardening. However, this method still results in insuff-icient hot flow and ~hus in insufficient strength of the molded articles.
In addition, a method has been proposed for using a solid ammonia resole resin as a curing agent for novolac resins. This method, though effective for improving the physical strength of the molded article,is associated with the serious drawback of slow curing.
The present inventors have found that these problems can be solved by using, as a curing agent for novolac resins, a lubricant-containing solid resole phenolic resin having a higher content of methylol radicals (here-inafter referred to as a lubricant-containing solid resole resln). The presence of a lubricant in the resin elevates the apparent melting point and thus improves its resistance against blocking.
As this method provides a solid resole resin having a high degree of reactivity (with a higher content of methylol radicals), it is possible to obtain a coated sand composition with a fast curing speed and with a h;gher crosslinking density. Also, the uniform distribution of lubricant ~- in the solid resole resin assures an improvement in hot flow and uniform mixing with the novolac resin.
Accordingly, it is an object o~ the present invention to provide a process for producing a resin-coated sand composition having good physical strenyth and rapid curing by means of the dry hot coating method.
Another object of the present invention is to provide a process for producing a resin-coated sand composition capable o~ substantially elimin-ating gas defects in cast products and also capable of preventing the various associated pollution problems.
A still further object of the present invention is to provide a process which utilizes a stable supply of a reactive binder substantially free of blocking characteristics and which provides for the simpli~ied preparation of a more reactive solid resole resin.
Summary of the Invention The present inventors have now succeeded in developing an improved foundry sand composition comprising sand, a solid novolac resin, a lubricant-containing solid resole resin reactive with said novolac resin, and op-tionally, hexamine present in an amount of up to about ~ parts by weight based on 100 parts by weight of the total amount of resin. The use of a lubricant-containing solid resole resin as a curing agent for the novolac resin in the preparation of resin-coated sand compositions provides satis-factory hot flow without substantial adverse blocking effects, and also provides the following significant advantages:
1) The substantial absence of defective castings and disagreeable odors due to gas formation;
Conventional resin-coated sand compositions have been typically prepared by the dry hot coating method by mixing heated sand particles with a novolac phenolic resin (hereinafter referred to as a novolac resin) in the form of an agitated aqueous solution, adding hexamethylenetetramine (hereinafter referred to as hexamine) as a hardening agent, in an amount of 10 to 15 parts by we;ght with respect to 100 parts by weight of resin, and further adding calcium stearate.
Such resin-coated sand compositions produced with novolac resins and lS hexamine exhibit fast curing and excellent flow, but are also often as-sociated with certain drawbacks such as pollution problems and defects in the cast products, such as pinholes or blow holes resulting from the presence of nitrogen compounds, such as ammonia or formaldehyde, generated - by the pyrolysis of hexamine when the resin-coated sand compositions are ~ used in iron or steel casting or when forming molds.
In order to avoid such problems, various attempts have been made to . employ a shell molding resin with a very low nitrogen content when using dry hot coating methods. A representative attempt in this direction is the use of a sotid resole phenolic resin obtained with an ammonia catalyst (hereinafter referred to as a solid ammonia resole resin).
aF
This method is, however, associated with certain drawbacks such as slower hardening as compared to novolac resins cured with hexamine, and unsatisfactory flow (insufficient hot flow) resulting from premature local curing before the sand particles become well-coated in the course of mulling.
As a result, the cured articles frequently exhibit significantly lower physical strength than those obtained with a novolac resin and hexamine, and, therefore, this method has not been extensively employed in practice.
A method has also been proposed for controlling the degree o~ reaction of a solid ammonia resole resin in the earlier stages of reaction in order to accelerate the hardening. However, this method still results in insuff-icient hot flow and ~hus in insufficient strength of the molded articles.
In addition, a method has been proposed for using a solid ammonia resole resin as a curing agent for novolac resins. This method, though effective for improving the physical strength of the molded article,is associated with the serious drawback of slow curing.
The present inventors have found that these problems can be solved by using, as a curing agent for novolac resins, a lubricant-containing solid resole phenolic resin having a higher content of methylol radicals (here-inafter referred to as a lubricant-containing solid resole resln). The presence of a lubricant in the resin elevates the apparent melting point and thus improves its resistance against blocking.
As this method provides a solid resole resin having a high degree of reactivity (with a higher content of methylol radicals), it is possible to obtain a coated sand composition with a fast curing speed and with a h;gher crosslinking density. Also, the uniform distribution of lubricant ~- in the solid resole resin assures an improvement in hot flow and uniform mixing with the novolac resin.
Accordingly, it is an object o~ the present invention to provide a process for producing a resin-coated sand composition having good physical strenyth and rapid curing by means of the dry hot coating method.
Another object of the present invention is to provide a process for producing a resin-coated sand composition capable o~ substantially elimin-ating gas defects in cast products and also capable of preventing the various associated pollution problems.
A still further object of the present invention is to provide a process which utilizes a stable supply of a reactive binder substantially free of blocking characteristics and which provides for the simpli~ied preparation of a more reactive solid resole resin.
Summary of the Invention The present inventors have now succeeded in developing an improved foundry sand composition comprising sand, a solid novolac resin, a lubricant-containing solid resole resin reactive with said novolac resin, and op-tionally, hexamine present in an amount of up to about ~ parts by weight based on 100 parts by weight of the total amount of resin. The use of a lubricant-containing solid resole resin as a curing agent for the novolac resin in the preparation of resin-coated sand compositions provides satis-factory hot flow without substantial adverse blocking effects, and also provides the following significant advantages:
1) The substantial absence of defective castings and disagreeable odors due to gas formation;
2) Satisfactory hot flow and uniform ~ixing of the lubricant-containing resole with the novolac due to the presence of the lubricant, and satisfactory cure speed due to a higher content of reactive radicals in the solid resole resin;
3) A higher crosslinking density, and a resulting increase in strength of the molded articles, due to the use of a novolac resin in combination with a solid resole resin having a higher content ~f reactive radicals; and
4) The lack of, or very limited need for, the addition of a lub-ricant, such as calcium stearate, in the blending process for the preparation of resin-coated sand compositions thus facilitating the blending operation.
Descr;ption of the Preferred Embodiments The lubricant-containing solid resole resin employed in the present invention may be obtained by incorporating a lubricant into the base resin prepared by reacting l mole of phenol with at least l mole of formaldehyde in the presence of an alkaline catalyst.
Suitable solid resole resins include ammonia solid resole resins, prepared by using an amine catalyst such a ammonia or an amine compound, solid resole resins prepared by the combined use of an amine catalyst and an alkali metal catalyst, and solid resole resins prepared by using an alkali metal catalyst alone.
The phenolic reactant employed in the present invention to prepare the novolac or resole resin can be phenol, an alkylphenol such as m-cresol, p-cresol, xylenol or mixtures thereof.
As source of formaldehyde, in addition to formalin, forma1dehyde polymers such as paraformaldehyde or trioxane, or mixtures thereof, can be advantageously employed. In addition, hexamine can be employed not only as a catalyst, but also in combination with ammonia as a source of formaldehyde.
Examples of ami~e compounds applicable as amine catalysts are mono-methylamine, triethylamine, ethanolamine, aniline, etc.
11193~4 Typical examples of suitable alkali metal catalysts are hydroxides and oxides of alkali metals such as sodium, potassium and lithium, and hydroxides and oxides of alkali earth metals such as barium, calcium and magnesium.
Typical examples of suitable lubricants are carnauba wax, montan wax, paraffin wax, polyethylene wax, aliphatic amides such as ethylene bis-stearamide, methylene bis-stearamide, oxystear-amide, stearamides, linoleic amide, etc., aliphatic acid salts such as calcium stearate, rosin, "Vinsol" resin (a complex ther-moplastic mixture derived from southern pinewood comprising phen-olic constituents in the form of substituted phenolic ethers, polyphenols and phenols of high molecular weight), polyethylene-glycol, polystyrene, talc, etc. The preferred lubricant is an aliphatic amide or polyethylene wax.
Such a lubricant can be added prior to, during, or after the preparation of the solid resole resin to obtain a lubricant-containing solid resole resin. In order to achieve a homogeneous dispersion, the lubricant is added preferably prior to or during the reaction and preferably in the form of a dispersion. The amount of lubricant employed may vary within a range of about 0.5 to about 10 parts by weight based on 100 parts by weight of the solid resole resin, and preferably within a range of about 1 to about 7 parts by weight to achieve a more satisfactory hot flow and cure speed.
The following examples will serve to illustrate the process for producing the lubricant-containing solid resole resin of the present invent;on:
1) One mole of phenol and 1-3 moles of formaldehyde are placed in a reactor, and an alkaline catalyst is added thereto prior to the addition of a lubricant. The mixture thus obtained ,, . .:
- : : ' ` "~
11~933~
is subjected to a condensation reaction for about 30 minutes to 2 hours at a temperature of 50C to 100C. (The lubricant is preferably added after completion of the condensation reaction or subsequently during the course of dehydration.) The reaction mixture is then subjected to dehydration under reduced pressure and at a temperature not exceeding 100C. to obtain a highly vis-cous yellow or brownish-yellow resin, which is removed from the reactor, rapidly cooled and crushed to obtain a lubricant-contain-ing solid resole resin in solid state.
2) One mole of phenol and 1-3 moles of formaldehyde are placed in a reactor and an alkaline catalyst is added. The mix-ture obtained is subjected to a condensation reaction for about 30 minutes to 2 hours at a temperature of 50C. to 100C. A dis-persion of a lubricant is then added to the reaction mixture with a silane coupling agent, such as amino-silane or epoxysilane, and rapidly dried to obtain a lubricant-containing solid resole resin in flake or granular form.
3) A lubricant-containing solid resole resin can also be obtained by incorporating a lubricant into a ;olid resole resin modified by a modifier capable of reacting with formaldehyde such as resorcin, urea, melamine, cashew nut shell oil, etc.
The novolac resin employed in the presen~ invention is a solid condensate with a melting point of 70C to 100C prepared by the reaction of phenol and formaldehyde in the presence of an organic or inorganic acid catalyst such as oxalic acid, hydrochloric acid, sulfuric acid, p-toluenesulfonic acid or zinc acetate, followed by dehydration, said condensate being obtainable in flake, granular or rod shaped forms. Furthermore, in addition to ordinary novolac resins, so-called high ortho-novolac resins are also included in the novolac resins employed in the present invention. ~he prepara-tion of suitable high ortho-novolac resins is fully described in US Patent 3,425,989, to Shepard et al.
;
~ : ~ . ,,, ' :' :
1~933~
The novolac resin thus obtained is a thermoplastic. Hexamine is a representative curing agent for the novolac, but it is asso-ciated, as explained in the foregoing, with certain disadvantages such as defects in cast products and with disagreeable odors due to the formation of gas. Also, as explained in the foregoing, a solid resole resin is unsatisfactory as a curing agent due to its slow cure speed, although it is not associated with the above-mentioned disad~antages.
The amount of novolac employed should preferably be in the range of about 1 part by weight to about 30 parts by weight based on 100 parts by weight of the total amount of resin employed. The upper limit can be increased to about 40 parts by weight if hexa-mine is employed.
The resin-coated sand compositions of the present invention can be prepared by placing sand, preheated to 120C. to 140C, i.e.
at an elevated temperature sufficient to fluidize the solid resin into a muller, adding a novolac resin in flake, granular or rod shaped form, further adding the lubricant containing solid resole resin of the present invention, and if necessary, adding a small amount of hexamine dissolved in the cooling water, and continuing the mulling until the sand lumps are crushed, with the addition, when required, of a small amount of cal~ium stearate. The total resin content of the sand composition will preferably be in the range of about 2 to about 5 parts by weight based on 100 parts by weight of sand.
The present invention sill be further elucidated by the following examples which are not intended to limit the scope there-of. The amounts and percentages in the specification and claims are represented by parts by weight and percent by we;ght unless specifically defined otherwise.
2000 parts of phenol and 1350 parts of 37~ formalin were placed in a reactor, and 15 parts of 10% hydrochloric acid was added. The mixture was heated to 100C. and reacted under reflux for 3 hours.
. . -- ;
.
: , . . .
;
3;~
The reaction mixture was subjected, successively~ to dehydration under a reduced pressure of 30-65 cmHg, then removed from the re-actor when the internal temperature rose to 160C., allowed to cool, and crushed to obtain a novolac resin in granular form.
2000 parts of phenol and 2590 parts of 37% formalin were placed in a reactor, and 160 parts of a 28% ammonia solution was added.
The mixture was gradually heated to 100C and reacted under reflux for 30 minutes. After the addition and mixing of 100 parts of methylene bis-stearamide, the reaction mixture was subjected to de-hydration under a reduced pressure of 30-50 cmHg, then removed from the reactor when the internal temperature rose to 82C., rapidly cooled and crushed to obtain a solid resole resin with a melting point of 97C in granular form. The solid resole resin thus ob-tained was found to have no blocking characteristics.
2000 Parts of phenol and 2590 parts of 37% formaline wereplaced in a reactor, and 160 parts of a 28% aqueous ammonia so-lution and 60 parts of a 50% aqueous solution of sodium hydroxide were added. The mixture was gradually heated to 100C and reacted under reflux for 30 minutes. After the addition of 100 parts of ethylene bis-stearamide and dispersion by admixture, the mixture was subjected to dehydration under a reduced pressure~ then re-moved from the reactor when the internal temperature reached 82C, cooled rapidly and crushed to obtain a solid resole resin with a melting point of 97C in granular form. The solid resole resin thus obtained was found to have no blocking characteristics.
2000 Parts of phenol and 2590 parts of 37% formalin were placed in a reactor, and 160 parts of a 28% aqueous ammonia solution was added. The B
.... . . ...... ; .... ... ..... ~
.. . ., ...... ~ . . .. .
i ~ .
,. , . ~
. . - ~ .,.
~ 3 mixture was gradually heated to 100C. and reacted under reflux for 30 minutes. The mixture was subjected successively, to dehydration under a reduced pressure of 30-50 cmHg, removed from the reactor when the internal temperature rose to 95C. cooled rapidly and crushed to obtain a sol;d resole resin having a melting point of 85C. in granular form.
The conditions for preparation of resin-coated sand compositions, together with the properties thereof, based on the novolac resin obtained in Example 1 and the solid resole resin obtained in Examples 2 or 3, or Reference Example l, in some cases with hexamine, are summarized in Table l below.
The method of preparation of the resin-coated sand and the methods of testing were as follows:
l. Preparation of resin-coated sand:
30 Kg of "Ayaragi" silica sand preheated to 130-140C. was placed in a Whal mixer. A novolac resin (Example l) and a solid resole resin were added and mulled with the silica sand for 40 seconds. 450 9 of water (in which a predetermined amount of hexamine, if required, is dissolved) was added, and mulling was continued until the sand particles were crushed.
After the addition of 20 9 of calcium stearate, the mixture was further - mulled for 20 seconds, then removed from the mixer and aerated to obtain the resin-coated sand.
2. Test methods:
Bending strength (kg/cm2) : JACT test method SM-l Sticking point : JACT test method C-l Hot tensile strength (kglcm2) : JACT test method SM-lO
From the results in the foregoing and in Table l, it will be observed that, in order to achieve a higher strength and a faster cure (represented _ g _ 3~ ?3 3 ~
by the hot tensile strength value at 30 and 60 seconds), a lubricant-containing solid resole resin prepared using a mixture of ammonia and an alkal~ metal catalyst in combination is preferred to that prepared ~ith an ammonia catalyst alone.
RUN COtlTROL RU~
Cond~tlons of PreparatiOn of resin-cDated sand Ex. 1 ~novolac) (9) 250250 3S0 350 250350 900 1 0 EX. 2 (solid resole resin of the present in-ventlon) (g)6iO
Ex. 3 (solid resole resin ~ of the present in-1 5 vention) (9) - 650550 550 Ref. Ex. 1 (solid ammonia resole res~n( (g) - - - - 650 650 Hexam1ne - - 27 45 - 45 135 ~ropertles of restn-coated sand 2 0 Bending strength (kgjcm2) 44.9 46.5 43.J 42.5 35.5 33.2 43.3 Stick~ng point (~C.) 103102 104 104 100103 107 Hot tensile strength (kg~cr ) 30 sec. 1.8 2.4 1.7 1.8 1.1 t.4 2.1 2 5 60 sec.6.5 7.3 6.7 6.9 4.3 4.9 6.9 240 sec.19.5 22.1 20.3 19.8 14.5 15.3 20.6 - .... - -- . .
~ 10 --
Descr;ption of the Preferred Embodiments The lubricant-containing solid resole resin employed in the present invention may be obtained by incorporating a lubricant into the base resin prepared by reacting l mole of phenol with at least l mole of formaldehyde in the presence of an alkaline catalyst.
Suitable solid resole resins include ammonia solid resole resins, prepared by using an amine catalyst such a ammonia or an amine compound, solid resole resins prepared by the combined use of an amine catalyst and an alkali metal catalyst, and solid resole resins prepared by using an alkali metal catalyst alone.
The phenolic reactant employed in the present invention to prepare the novolac or resole resin can be phenol, an alkylphenol such as m-cresol, p-cresol, xylenol or mixtures thereof.
As source of formaldehyde, in addition to formalin, forma1dehyde polymers such as paraformaldehyde or trioxane, or mixtures thereof, can be advantageously employed. In addition, hexamine can be employed not only as a catalyst, but also in combination with ammonia as a source of formaldehyde.
Examples of ami~e compounds applicable as amine catalysts are mono-methylamine, triethylamine, ethanolamine, aniline, etc.
11193~4 Typical examples of suitable alkali metal catalysts are hydroxides and oxides of alkali metals such as sodium, potassium and lithium, and hydroxides and oxides of alkali earth metals such as barium, calcium and magnesium.
Typical examples of suitable lubricants are carnauba wax, montan wax, paraffin wax, polyethylene wax, aliphatic amides such as ethylene bis-stearamide, methylene bis-stearamide, oxystear-amide, stearamides, linoleic amide, etc., aliphatic acid salts such as calcium stearate, rosin, "Vinsol" resin (a complex ther-moplastic mixture derived from southern pinewood comprising phen-olic constituents in the form of substituted phenolic ethers, polyphenols and phenols of high molecular weight), polyethylene-glycol, polystyrene, talc, etc. The preferred lubricant is an aliphatic amide or polyethylene wax.
Such a lubricant can be added prior to, during, or after the preparation of the solid resole resin to obtain a lubricant-containing solid resole resin. In order to achieve a homogeneous dispersion, the lubricant is added preferably prior to or during the reaction and preferably in the form of a dispersion. The amount of lubricant employed may vary within a range of about 0.5 to about 10 parts by weight based on 100 parts by weight of the solid resole resin, and preferably within a range of about 1 to about 7 parts by weight to achieve a more satisfactory hot flow and cure speed.
The following examples will serve to illustrate the process for producing the lubricant-containing solid resole resin of the present invent;on:
1) One mole of phenol and 1-3 moles of formaldehyde are placed in a reactor, and an alkaline catalyst is added thereto prior to the addition of a lubricant. The mixture thus obtained ,, . .:
- : : ' ` "~
11~933~
is subjected to a condensation reaction for about 30 minutes to 2 hours at a temperature of 50C to 100C. (The lubricant is preferably added after completion of the condensation reaction or subsequently during the course of dehydration.) The reaction mixture is then subjected to dehydration under reduced pressure and at a temperature not exceeding 100C. to obtain a highly vis-cous yellow or brownish-yellow resin, which is removed from the reactor, rapidly cooled and crushed to obtain a lubricant-contain-ing solid resole resin in solid state.
2) One mole of phenol and 1-3 moles of formaldehyde are placed in a reactor and an alkaline catalyst is added. The mix-ture obtained is subjected to a condensation reaction for about 30 minutes to 2 hours at a temperature of 50C. to 100C. A dis-persion of a lubricant is then added to the reaction mixture with a silane coupling agent, such as amino-silane or epoxysilane, and rapidly dried to obtain a lubricant-containing solid resole resin in flake or granular form.
3) A lubricant-containing solid resole resin can also be obtained by incorporating a lubricant into a ;olid resole resin modified by a modifier capable of reacting with formaldehyde such as resorcin, urea, melamine, cashew nut shell oil, etc.
The novolac resin employed in the presen~ invention is a solid condensate with a melting point of 70C to 100C prepared by the reaction of phenol and formaldehyde in the presence of an organic or inorganic acid catalyst such as oxalic acid, hydrochloric acid, sulfuric acid, p-toluenesulfonic acid or zinc acetate, followed by dehydration, said condensate being obtainable in flake, granular or rod shaped forms. Furthermore, in addition to ordinary novolac resins, so-called high ortho-novolac resins are also included in the novolac resins employed in the present invention. ~he prepara-tion of suitable high ortho-novolac resins is fully described in US Patent 3,425,989, to Shepard et al.
;
~ : ~ . ,,, ' :' :
1~933~
The novolac resin thus obtained is a thermoplastic. Hexamine is a representative curing agent for the novolac, but it is asso-ciated, as explained in the foregoing, with certain disadvantages such as defects in cast products and with disagreeable odors due to the formation of gas. Also, as explained in the foregoing, a solid resole resin is unsatisfactory as a curing agent due to its slow cure speed, although it is not associated with the above-mentioned disad~antages.
The amount of novolac employed should preferably be in the range of about 1 part by weight to about 30 parts by weight based on 100 parts by weight of the total amount of resin employed. The upper limit can be increased to about 40 parts by weight if hexa-mine is employed.
The resin-coated sand compositions of the present invention can be prepared by placing sand, preheated to 120C. to 140C, i.e.
at an elevated temperature sufficient to fluidize the solid resin into a muller, adding a novolac resin in flake, granular or rod shaped form, further adding the lubricant containing solid resole resin of the present invention, and if necessary, adding a small amount of hexamine dissolved in the cooling water, and continuing the mulling until the sand lumps are crushed, with the addition, when required, of a small amount of cal~ium stearate. The total resin content of the sand composition will preferably be in the range of about 2 to about 5 parts by weight based on 100 parts by weight of sand.
The present invention sill be further elucidated by the following examples which are not intended to limit the scope there-of. The amounts and percentages in the specification and claims are represented by parts by weight and percent by we;ght unless specifically defined otherwise.
2000 parts of phenol and 1350 parts of 37~ formalin were placed in a reactor, and 15 parts of 10% hydrochloric acid was added. The mixture was heated to 100C. and reacted under reflux for 3 hours.
. . -- ;
.
: , . . .
;
3;~
The reaction mixture was subjected, successively~ to dehydration under a reduced pressure of 30-65 cmHg, then removed from the re-actor when the internal temperature rose to 160C., allowed to cool, and crushed to obtain a novolac resin in granular form.
2000 parts of phenol and 2590 parts of 37% formalin were placed in a reactor, and 160 parts of a 28% ammonia solution was added.
The mixture was gradually heated to 100C and reacted under reflux for 30 minutes. After the addition and mixing of 100 parts of methylene bis-stearamide, the reaction mixture was subjected to de-hydration under a reduced pressure of 30-50 cmHg, then removed from the reactor when the internal temperature rose to 82C., rapidly cooled and crushed to obtain a solid resole resin with a melting point of 97C in granular form. The solid resole resin thus ob-tained was found to have no blocking characteristics.
2000 Parts of phenol and 2590 parts of 37% formaline wereplaced in a reactor, and 160 parts of a 28% aqueous ammonia so-lution and 60 parts of a 50% aqueous solution of sodium hydroxide were added. The mixture was gradually heated to 100C and reacted under reflux for 30 minutes. After the addition of 100 parts of ethylene bis-stearamide and dispersion by admixture, the mixture was subjected to dehydration under a reduced pressure~ then re-moved from the reactor when the internal temperature reached 82C, cooled rapidly and crushed to obtain a solid resole resin with a melting point of 97C in granular form. The solid resole resin thus obtained was found to have no blocking characteristics.
2000 Parts of phenol and 2590 parts of 37% formalin were placed in a reactor, and 160 parts of a 28% aqueous ammonia solution was added. The B
.... . . ...... ; .... ... ..... ~
.. . ., ...... ~ . . .. .
i ~ .
,. , . ~
. . - ~ .,.
~ 3 mixture was gradually heated to 100C. and reacted under reflux for 30 minutes. The mixture was subjected successively, to dehydration under a reduced pressure of 30-50 cmHg, removed from the reactor when the internal temperature rose to 95C. cooled rapidly and crushed to obtain a sol;d resole resin having a melting point of 85C. in granular form.
The conditions for preparation of resin-coated sand compositions, together with the properties thereof, based on the novolac resin obtained in Example 1 and the solid resole resin obtained in Examples 2 or 3, or Reference Example l, in some cases with hexamine, are summarized in Table l below.
The method of preparation of the resin-coated sand and the methods of testing were as follows:
l. Preparation of resin-coated sand:
30 Kg of "Ayaragi" silica sand preheated to 130-140C. was placed in a Whal mixer. A novolac resin (Example l) and a solid resole resin were added and mulled with the silica sand for 40 seconds. 450 9 of water (in which a predetermined amount of hexamine, if required, is dissolved) was added, and mulling was continued until the sand particles were crushed.
After the addition of 20 9 of calcium stearate, the mixture was further - mulled for 20 seconds, then removed from the mixer and aerated to obtain the resin-coated sand.
2. Test methods:
Bending strength (kg/cm2) : JACT test method SM-l Sticking point : JACT test method C-l Hot tensile strength (kglcm2) : JACT test method SM-lO
From the results in the foregoing and in Table l, it will be observed that, in order to achieve a higher strength and a faster cure (represented _ g _ 3~ ?3 3 ~
by the hot tensile strength value at 30 and 60 seconds), a lubricant-containing solid resole resin prepared using a mixture of ammonia and an alkal~ metal catalyst in combination is preferred to that prepared ~ith an ammonia catalyst alone.
RUN COtlTROL RU~
Cond~tlons of PreparatiOn of resin-cDated sand Ex. 1 ~novolac) (9) 250250 3S0 350 250350 900 1 0 EX. 2 (solid resole resin of the present in-ventlon) (g)6iO
Ex. 3 (solid resole resin ~ of the present in-1 5 vention) (9) - 650550 550 Ref. Ex. 1 (solid ammonia resole res~n( (g) - - - - 650 650 Hexam1ne - - 27 45 - 45 135 ~ropertles of restn-coated sand 2 0 Bending strength (kgjcm2) 44.9 46.5 43.J 42.5 35.5 33.2 43.3 Stick~ng point (~C.) 103102 104 104 100103 107 Hot tensile strength (kg~cr ) 30 sec. 1.8 2.4 1.7 1.8 1.1 t.4 2.1 2 5 60 sec.6.5 7.3 6.7 6.9 4.3 4.9 6.9 240 sec.19.5 22.1 20.3 19.8 14.5 15.3 20.6 - .... - -- . .
~ 10 --
Claims
The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
In the process for preparation of a composition useful as a foundry core or mold consisting essentially of sand and a phenolic resin wherein a mixture of the phenolic resin consisting of solid particles and sand at an elevated temperature sufficient to fluid-ize said solid resin are mulled to coat the sand with said resin, the improvement wherein the solid phenolic resin comprises a solid novolac phenolic resin and a lubricant-containing solid resole phenolic resin produced by the reaction comprising a) condensation of a phenol and a formaldehyde source and b) subsequent dehydra-tion of the condensation mixture wherein the lubricant is added prior to completion of said reaction to produce the solid resole phenolic resin, the novolac resin constituting about 1 to about 40 parts by weight per 100 parts by weight of the phenolic resin, and the lubricant-containing resole phenolic resin constituting the balance of the phenolic resin component, the proportion of the total phenolic resin being about 2 to about 5 parts by weight per 100 parts by weight of the sand and the proportion of lubri-cant in the resole resin component being about 0.5 to about 10 parts by weight per 100 parts by weight of the resole resin component.
The process of Claim 1 wherein the lubricant is selected from the group consisting of carnauba wax, montan wax, paraffin wax, polyethylene wax, aliphatic amides, rosin, a complex ther-moplastic mixture derived from southern pinewood comprising phenolic constituents in the form of substituted phenolic ethers, polyphenols and phenols of high molecular weight, polyethylene-glycol, polystyrene, talc, and mixtures thereof.
The process of Claim 2 wherein the lubricant is an aliphatic amide or a polyethylene wax.
The process of Claim 1 wherein the novolac resin comprises a condensation product of phenol and formaldehyde.
The process of Claim 1 wherein the resole resin comprises a condensation product of phenol and formaldehyde.
The process of Claim 1 wherein the temperature of the sand is 102°C to 140°C.
The process of Claim 6 wherein the novolac resin is present in an amount of about 1 to about 30 parts by weight based on 100 parts by weight of the total resin content.
A product useful as a foundry sand core or mold prepared by the process of Claim 7.
The process of Claim 7 wherein the lubricant is present in an amount of about 1 to about 7 parts by weight based on 100 parts by weight of the resole resin.
The process of Claim 1 wherein the lubricant-containing resole resin also includes a silane coupling agent.
The process of Claim 1 wherein the mixture of sand and resin also includes hexamine in an amount of up to about 5 parts by weight based on 100 parts by weight of the total resin.
A product useful as a foundry sand core or mold prepared by the process of Claim 11.
A product useful as a foundry sand core or mold prepared by the process of Claim 1.
The process of Claim 1 wherein the lubricant is added after completion of the condensation step of the reaction to produce the solid phenolic resin.
A product useful as a sand core or mold prepared by the process of Claim 14.
In a solid phenolic resin composition for binding sand in a foundry sand core or mold, prepared by mixing solid novolac and solid resole resin particles, the improvement wherein said re-sole comprises a lubricant-containing resole produced by the re-action comprising a) condensation of a phenol and a formaldehyde source in the presence of an alkaline catalyst and b) subsequent dehydration of the condensation mixture, wherein the lubricant is added to the completion of said reaction to produce said solid resole in a proportion of about 0.5 to about 10 parts by weight per 100 parts by weight of the lubricant-containing resole, the solid novolac constituting about 1 part to about 40 parts by weight per 100 parts by weight of the novolac and lubricant-containing resole resins, and the lubricant-containing resole constituting the balance of the composition.
The composition of Claim 16, wherein the lubricant is selected from the group consisting of carnauba wax, montan wax, paraffin wax, polyethylene wax, aliphatic amides, rosin, a resin-ous material comprising a complex thermoplastic mixture derived from the southern pinewood comprising phenolic constituents in the form of substituted phenolic ethers, polyphenols, and phenols of high molecular weight, polyethylene glycol, polystyrene, talc and mixtures thereof.
The composition of Claim 17 wherein the lubricant is an aliphatic amide or a polyethylene wax.
The composition of Claim 16, wherein the novolac resin comprises a condensation product of phenol and formaldehyde.
The composition of Claim 16, wherein the resole resin comprises a condensation product of phenol and formaldehyde.
The composition of Claim 20, wherein the novolac resin is present in an amount of about 1 to about 30 parts by weight based on 100 parts by weight of the novolac and the lubricant-containing resole resins.
The composition of Claim 21, wherein the lubricant is present in an amount of about 1 to about 7 parts by weight based on 100 parts by weight of the lubricant-containing resole resin.
The composition of Claim 16 wherein the lubricant-containing resole resin also includes a silane coupling agent.
The composition of Claim 16, wherein the lubricant is added during the condensation step of the reaction employed to prepare the solid resole resin.
The composition of Claim 16 wherein the lubricant is added subsequent to the condensation step of the reaction employed to prepare the solid resole.
The composition of Claim 16 wherein the resole is prepared in the presence of an alkaline catalyst and an amine catalyst, said alkaline catalyst being selected from the group consisting of alkali metal hydroxides, alkali metal oxides, alkaline earth metal hydroxides, alkaline earth oxides and mixtures thereof and said amine catalyst being selected from the group consis-ting of ammonia, monomethyl amine, triethyl amine, ethanol-amine, an aniline and mixtures thereof.
The composition of Claim 26 wherein the phenolic reactant is phenol.
The composition of Claim 27 wherein the alkaline catalysts sodium hydroxide.
The composition of Claim 27 wherein the alkaline catalysts barium hydroxide.
The composition of Claim 26 wherein the amine catalysts ammonia.
The process of Claim 1 wherein said resole is prepared in the presence of an alkaline catalyst selected from the group consist-ing of alkali metal hydroxides, alkali metal oxides, alkaline earth metal hydroxides, alkaline earth metal oxides and mixtures thereof and an amine catalyst selected from the group consisting of ammonia monomethyl amine, triethyl amine, ethanol amine, an aniline and mix-tures thereof.
The process of Claim 31 wherein the lubricant is selected from the group consisting of carnauba wax, montan wax, paraffin wax, polyethylene wax, aliphatic amides, rosin, a complex ther-moplastic mixture derived from southern pinewood comprising phenolic constituents in the form of substituted phenolic ethers, polyphenols and phenols of high molecular weight, polyethylene glycol, polystyrene, talc and mixtures thereof, the novolac resin comprises a condensation product of phenol and formaldehyde, the resole resin comprises the condensation product of phenol and formaldehyde, the alkaline catalyst is an alkali metal hydroxide, the amine catalyst is ammonia, the mixture of sand and resin also includes hexamine in an amount of up to about 5 parts by weight per 100 parts by weight of the novolac and lubricant-containing resole and the novolac is present in an amount of about 1 to to about 30 parts by weight based on 100 parts by weight of the novolac and the lubricant-containing resole.
The process of Claim 32 wherein the lubricant is added after completion of the condensation step of the reaction to produce the solid resole resin in a proportion of about 1 to about 7 parts per 100 parts by weight of the lubricant-containing resole resin, the lubricant-containing resole also includes a silane coupling agent and the alkali hydroxide catalyst is sodium hydroxide.
A product use ful as a foundry sand core or mold prepared by the process of Claim 31.
In the process for preparation of a composition useful as a foundry core or mold consisting essentially of sand and a phenolic resin wherein a mixture of the phenolic resin consisting of solid particles and sand at an elevated temperature sufficient to fluid-ize said solid resin are mulled to coat the sand with said resin, the improvement wherein the solid phenolic resin comprises a solid novolac phenolic resin and a lubricant-containing solid resole phenolic resin produced by the reaction comprising a) condensation of a phenol and a formaldehyde source and b) subsequent dehydra-tion of the condensation mixture wherein the lubricant is added prior to completion of said reaction to produce the solid resole phenolic resin, the novolac resin constituting about 1 to about 40 parts by weight per 100 parts by weight of the phenolic resin, and the lubricant-containing resole phenolic resin constituting the balance of the phenolic resin component, the proportion of the total phenolic resin being about 2 to about 5 parts by weight per 100 parts by weight of the sand and the proportion of lubri-cant in the resole resin component being about 0.5 to about 10 parts by weight per 100 parts by weight of the resole resin component.
The process of Claim 1 wherein the lubricant is selected from the group consisting of carnauba wax, montan wax, paraffin wax, polyethylene wax, aliphatic amides, rosin, a complex ther-moplastic mixture derived from southern pinewood comprising phenolic constituents in the form of substituted phenolic ethers, polyphenols and phenols of high molecular weight, polyethylene-glycol, polystyrene, talc, and mixtures thereof.
The process of Claim 2 wherein the lubricant is an aliphatic amide or a polyethylene wax.
The process of Claim 1 wherein the novolac resin comprises a condensation product of phenol and formaldehyde.
The process of Claim 1 wherein the resole resin comprises a condensation product of phenol and formaldehyde.
The process of Claim 1 wherein the temperature of the sand is 102°C to 140°C.
The process of Claim 6 wherein the novolac resin is present in an amount of about 1 to about 30 parts by weight based on 100 parts by weight of the total resin content.
A product useful as a foundry sand core or mold prepared by the process of Claim 7.
The process of Claim 7 wherein the lubricant is present in an amount of about 1 to about 7 parts by weight based on 100 parts by weight of the resole resin.
The process of Claim 1 wherein the lubricant-containing resole resin also includes a silane coupling agent.
The process of Claim 1 wherein the mixture of sand and resin also includes hexamine in an amount of up to about 5 parts by weight based on 100 parts by weight of the total resin.
A product useful as a foundry sand core or mold prepared by the process of Claim 11.
A product useful as a foundry sand core or mold prepared by the process of Claim 1.
The process of Claim 1 wherein the lubricant is added after completion of the condensation step of the reaction to produce the solid phenolic resin.
A product useful as a sand core or mold prepared by the process of Claim 14.
In a solid phenolic resin composition for binding sand in a foundry sand core or mold, prepared by mixing solid novolac and solid resole resin particles, the improvement wherein said re-sole comprises a lubricant-containing resole produced by the re-action comprising a) condensation of a phenol and a formaldehyde source in the presence of an alkaline catalyst and b) subsequent dehydration of the condensation mixture, wherein the lubricant is added to the completion of said reaction to produce said solid resole in a proportion of about 0.5 to about 10 parts by weight per 100 parts by weight of the lubricant-containing resole, the solid novolac constituting about 1 part to about 40 parts by weight per 100 parts by weight of the novolac and lubricant-containing resole resins, and the lubricant-containing resole constituting the balance of the composition.
The composition of Claim 16, wherein the lubricant is selected from the group consisting of carnauba wax, montan wax, paraffin wax, polyethylene wax, aliphatic amides, rosin, a resin-ous material comprising a complex thermoplastic mixture derived from the southern pinewood comprising phenolic constituents in the form of substituted phenolic ethers, polyphenols, and phenols of high molecular weight, polyethylene glycol, polystyrene, talc and mixtures thereof.
The composition of Claim 17 wherein the lubricant is an aliphatic amide or a polyethylene wax.
The composition of Claim 16, wherein the novolac resin comprises a condensation product of phenol and formaldehyde.
The composition of Claim 16, wherein the resole resin comprises a condensation product of phenol and formaldehyde.
The composition of Claim 20, wherein the novolac resin is present in an amount of about 1 to about 30 parts by weight based on 100 parts by weight of the novolac and the lubricant-containing resole resins.
The composition of Claim 21, wherein the lubricant is present in an amount of about 1 to about 7 parts by weight based on 100 parts by weight of the lubricant-containing resole resin.
The composition of Claim 16 wherein the lubricant-containing resole resin also includes a silane coupling agent.
The composition of Claim 16, wherein the lubricant is added during the condensation step of the reaction employed to prepare the solid resole resin.
The composition of Claim 16 wherein the lubricant is added subsequent to the condensation step of the reaction employed to prepare the solid resole.
The composition of Claim 16 wherein the resole is prepared in the presence of an alkaline catalyst and an amine catalyst, said alkaline catalyst being selected from the group consisting of alkali metal hydroxides, alkali metal oxides, alkaline earth metal hydroxides, alkaline earth oxides and mixtures thereof and said amine catalyst being selected from the group consis-ting of ammonia, monomethyl amine, triethyl amine, ethanol-amine, an aniline and mixtures thereof.
The composition of Claim 26 wherein the phenolic reactant is phenol.
The composition of Claim 27 wherein the alkaline catalysts sodium hydroxide.
The composition of Claim 27 wherein the alkaline catalysts barium hydroxide.
The composition of Claim 26 wherein the amine catalysts ammonia.
The process of Claim 1 wherein said resole is prepared in the presence of an alkaline catalyst selected from the group consist-ing of alkali metal hydroxides, alkali metal oxides, alkaline earth metal hydroxides, alkaline earth metal oxides and mixtures thereof and an amine catalyst selected from the group consisting of ammonia monomethyl amine, triethyl amine, ethanol amine, an aniline and mix-tures thereof.
The process of Claim 31 wherein the lubricant is selected from the group consisting of carnauba wax, montan wax, paraffin wax, polyethylene wax, aliphatic amides, rosin, a complex ther-moplastic mixture derived from southern pinewood comprising phenolic constituents in the form of substituted phenolic ethers, polyphenols and phenols of high molecular weight, polyethylene glycol, polystyrene, talc and mixtures thereof, the novolac resin comprises a condensation product of phenol and formaldehyde, the resole resin comprises the condensation product of phenol and formaldehyde, the alkaline catalyst is an alkali metal hydroxide, the amine catalyst is ammonia, the mixture of sand and resin also includes hexamine in an amount of up to about 5 parts by weight per 100 parts by weight of the novolac and lubricant-containing resole and the novolac is present in an amount of about 1 to to about 30 parts by weight based on 100 parts by weight of the novolac and the lubricant-containing resole.
The process of Claim 32 wherein the lubricant is added after completion of the condensation step of the reaction to produce the solid resole resin in a proportion of about 1 to about 7 parts per 100 parts by weight of the lubricant-containing resole resin, the lubricant-containing resole also includes a silane coupling agent and the alkali hydroxide catalyst is sodium hydroxide.
A product use ful as a foundry sand core or mold prepared by the process of Claim 31.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000294627A CA1119334A (en) | 1978-01-09 | 1978-01-09 | Novalac lubricant-containing resole-sand composition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000294627A CA1119334A (en) | 1978-01-09 | 1978-01-09 | Novalac lubricant-containing resole-sand composition |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1119334A true CA1119334A (en) | 1982-03-02 |
Family
ID=4110496
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000294627A Expired CA1119334A (en) | 1978-01-09 | 1978-01-09 | Novalac lubricant-containing resole-sand composition |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1119334A (en) |
-
1978
- 1978-01-09 CA CA000294627A patent/CA1119334A/en not_active Expired
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