GB2177408A - Foundry binder compositions - Google Patents
Foundry binder compositions Download PDFInfo
- Publication number
- GB2177408A GB2177408A GB08516669A GB8516669A GB2177408A GB 2177408 A GB2177408 A GB 2177408A GB 08516669 A GB08516669 A GB 08516669A GB 8516669 A GB8516669 A GB 8516669A GB 2177408 A GB2177408 A GB 2177408A
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- GB
- United Kingdom
- Prior art keywords
- phenol
- weight
- sodium hydroxide
- mole ratio
- aldehyde
- 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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- 239000000203 mixture Substances 0.000 title claims abstract description 74
- 239000011230 binding agent Substances 0.000 title claims abstract description 35
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims abstract description 144
- 229920005989 resin Polymers 0.000 claims abstract description 70
- 239000011347 resin Substances 0.000 claims abstract description 70
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N Phenol Chemical compound OC1=CC=CC=C1 ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 claims abstract description 55
- 239000007787 solid Substances 0.000 claims abstract description 46
- 229920003987 resole Polymers 0.000 claims abstract description 41
- 239000003513 alkali Substances 0.000 claims abstract description 29
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 23
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 20
- 150000001299 aldehydes Chemical class 0.000 claims abstract description 17
- 239000011819 refractory material Substances 0.000 claims abstract description 7
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims description 30
- 238000000034 method Methods 0.000 claims description 12
- 150000002148 esters Chemical class 0.000 claims description 6
- 150000002596 lactones Chemical class 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 5
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 claims description 4
- 150000002989 phenols Chemical class 0.000 claims description 4
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 claims description 4
- 229910000077 silane Inorganic materials 0.000 claims description 4
- 150000005846 sugar alcohols Polymers 0.000 claims description 3
- 125000000008 (C1-C10) alkyl group Chemical group 0.000 claims 1
- 150000001732 carboxylic acid derivatives Chemical class 0.000 claims 1
- KWYUFKZDYYNOTN-UHFFFAOYSA-M potassium hydroxide Inorganic materials [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 29
- 229940083608 sodium hydroxide Drugs 0.000 description 26
- 235000011121 sodium hydroxide Nutrition 0.000 description 26
- 239000000243 solution Substances 0.000 description 16
- 229920001568 phenolic resin Polymers 0.000 description 8
- 239000004576 sand Substances 0.000 description 7
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 6
- SLGWESQGEUXWJQ-UHFFFAOYSA-N formaldehyde;phenol Chemical compound O=C.OC1=CC=CC=C1 SLGWESQGEUXWJQ-UHFFFAOYSA-N 0.000 description 6
- 229910052708 sodium Inorganic materials 0.000 description 6
- 239000011734 sodium Substances 0.000 description 6
- 238000007906 compression Methods 0.000 description 5
- 230000006835 compression Effects 0.000 description 5
- 238000009472 formulation Methods 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- URAYPUMNDPQOKB-UHFFFAOYSA-N triacetin Chemical compound CC(=O)OCC(OC(C)=O)COC(C)=O URAYPUMNDPQOKB-UHFFFAOYSA-N 0.000 description 4
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 3
- 229930040373 Paraformaldehyde Natural products 0.000 description 3
- 238000009835 boiling Methods 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 229920002866 paraformaldehyde Polymers 0.000 description 3
- KXGFMDJXCMQABM-UHFFFAOYSA-N 2-methoxy-6-methylphenol Chemical compound [CH]OC1=CC=CC([CH])=C1O KXGFMDJXCMQABM-UHFFFAOYSA-N 0.000 description 2
- YEJRWHAVMIAJKC-UHFFFAOYSA-N 4-Butyrolactone Chemical compound O=C1CCCO1 YEJRWHAVMIAJKC-UHFFFAOYSA-N 0.000 description 2
- OZJPLYNZGCXSJM-UHFFFAOYSA-N 5-valerolactone Chemical compound O=C1CCCCO1 OZJPLYNZGCXSJM-UHFFFAOYSA-N 0.000 description 2
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 2
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 description 2
- 239000001087 glyceryl triacetate Substances 0.000 description 2
- 235000013773 glyceryl triacetate Nutrition 0.000 description 2
- 230000005484 gravity Effects 0.000 description 2
- 239000004848 polyfunctional curative Substances 0.000 description 2
- 150000004756 silanes Chemical class 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229960002622 triacetin Drugs 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Natural products CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- -1 butyro- Chemical class 0.000 description 1
- 229930188620 butyrolactone Natural products 0.000 description 1
- 150000001735 carboxylic acids Chemical class 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- WBJINCZRORDGAQ-UHFFFAOYSA-N formic acid ethyl ester Natural products CCOC=O WBJINCZRORDGAQ-UHFFFAOYSA-N 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 150000002895 organic esters Chemical class 0.000 description 1
- 239000005011 phenolic resin Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- FKRCODPIKNYEAC-UHFFFAOYSA-N propionic acid ethyl ester Natural products CCOC(=O)CC FKRCODPIKNYEAC-UHFFFAOYSA-N 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- ILJSQTXMGCGYMG-UHFFFAOYSA-N triacetic acid Chemical compound CC(=O)CC(=O)CC(O)=O ILJSQTXMGCGYMG-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G8/00—Condensation polymers of aldehydes or ketones with phenols only
- C08G8/04—Condensation polymers of aldehydes or ketones with phenols only of aldehydes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
- B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
- B22C1/20—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents
- B22C1/22—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents of resins or rosins
- B22C1/2233—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents of resins or rosins obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- B22C1/2246—Condensation polymers of aldehydes and ketones
- B22C1/2253—Condensation polymers of aldehydes and ketones with phenols
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L61/00—Compositions of condensation polymers of aldehydes or ketones; Compositions of derivatives of such polymers
- C08L61/04—Condensation polymers of aldehydes or ketones with phenols only
- C08L61/06—Condensation polymers of aldehydes or ketones with phenols only of aldehydes with phenols
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Mold Materials And Core Materials (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
Foundry cores and moulds are made by forming a mixture of granular refractory material and an aqueous binder composition, the mixture is formed and then allowed to cure. The aqueous foundry binder composition used comprises: (A) alkaline phenol-aldehyde resin comprising: (i) 40 to 95% by weight, based on the weight of the solids components of resin A, of an alkaline phenol- aldehyde resole having a phenol to aldehyde mole ratio of 1:2 to 1:3, and a phenol to alkali mole ratio of 1:0.5 to 1:1.2, the phenol-aldehyde resole, when dissolved in water at 45 to 50% by weight solids content in the presence of sodium hydroxide at a phenol to sodium hydroxide mole ratio of 1:1, having a viscosity of 50 to 350 centipoise at 20 DEG C, and (ii) 5 to 60% by weight, based on the weight of the solids components of resin A, of an alkaline phenol- aldehyde resole having a phenol to aldehyde mole ratio of 1:1.5 to 1:3.0, and a phenol to alkali mole ratio of 1:0.5 to 1:1.2; the phenol-aldehyde resole, when dissolved in water at 45 to 50% by weight solids content in the presence of sodium hydroxide at a phenol to sodium hydroxide mole ratio of 1:1, having a viscosity of 1000 to 5000 centipoise at 20 DEG C, and (B) a curing agent therefor. r
Description
SPECIFICATION
Foundry binder compositions
This invention relates to foundry binder compositions and to the manufacture of foundry moulds and cores using such compositions.
In the foundry industry it is known to use binder compositions based on alkaline phenolaldehyde resoles inthe manufacture of foundry moulds and cores. Such foundry binder compositions comprising the alkaline phenol-aldehyde resoles and a curing agent, or hardener, therefor are mixed with granular refractory material, e.g. sand, the mixture is formed and allowed to set. It is important to the use of the binder composition that the mould or core made using it develops strength sufficiently quickly (i.e. has fast cure speed) to permit early stripping of the mould or core from its former as well as having satisfactory strength developed over time (24 hour strength). In addition, of course, the cost of any binder composition is very important.
Many alkaline phenol-aldehyde resol foundry binder compositions tend to produce weak moulds or cores or require the use of unacceptable additives.
Japanese Patet Publication No: 50-130627 discloses the use in foundry mould manufacture of an organic ester (including lactones) as hardener for a sodium alkaline phenol-formaldehyde resole resin.
According to GB 2059972A and European 0072333, there is used a foundry binder composition comprising so-called potassium or sodium hydroxide phenolic resin and, as curing agent therefor, a lactone. The resins described in these references have a solids content of between 60 to 95% by weight and a viscosity in the range of 0.5 to 100 poises at 25"C.
While the Japanese Publication and British and European Specifications disclose compositions which are practically useful and give rise to strengths adequate for some foundry applications, the high levels of resin addition necessary render the system relatively expensive compared with other types of foundry binder compositions. The potassium hydroxide resins of GB 2059972 and European 0027333 generally provide compositions leading to moulds and cores having greater strengths than their sodium based counterparts. However the potassium hydroxide resins are appreciably more expensive than the sodium ones making the binder more expensive and reatively expensive compared with other types of foundry binders.
European 0085512 describes the use of foundry binder compositions containing highly condensed potassium alkaline phenol-formaldehyde resoles. According to this specification there may be obtained, using the resins described, moulds and cores of acceptable cure speed and 24 hour strength at lower addition levels than had been possible with the previous compositions. However the use of highly condensed resins which have relatively high molecular weights is in general disadvantageous as, for a given resin formulation, the higher the molecular weight the higher will be the viscosity of the resin solution. In the majority of foundry applications, there is an upper limit of resin viscosity that can be used and therefore the use of highly condensed resins restricts the scope for variations in resin formulation.For example, using a highly condensed resin the maximum permissible solids content will be lower than in the case where a less highly condensed resin is used if the resin solution is to have acceptable viscosity for foundry use. A further restriction on formulation imposed by the use of highly condensed resins is in the choice of alkali. It is necessary to use as alkali a material which will provide resin solutions of low viscosity and high solids content and European 0085512 specifies the use of potassium hydroxide.
The cheaper sodium hydroxide when used on an equimolar basis gives solutions of highly condensed resins which are relatively viscous and unsuitable for foundry use. Using potassium hydroxide as alkali the resin solutions of
European 0085512 tend towards the upper limits of acceptable viscosity.
Resins of this type require the use of large proportions of alkali so alkali cost in their preparation is significant. The need to use relatively costly potassium hydroxide as alkali is therefore a disadvantage of European 0085512. This specification states that some sodium hydroxide may be present with the potassium hydroxide but the use of the former in large proportions results in inferior resin performance.
According to the present invention there is provided an aqueous foundry binder composition which comprises: (A) alkaline phenol-aldehyde resin comprising: (i) 40 to 95% by weight, based on the
weight of the solids components of resin
A, of an alkaline phenol-aldehyde resole
having a phenol to aldehyde mole ratio of
1:2 to 1:3, and a phenol to alkali mole
ratio of 1:0.5 to 1:1.2; the phenol-al
dehyde resole, when dissolved in water at
45 to 50% by weight solids content in the
presence of sodium hydroxide at a phenol
to sodium hydroxide mole ratio of 1:1,
having a viscosity of 50 to 350 centipoise
at 20"C, and (ii) 5 to 60% by weight, based on the weight
of the solids components of resin A, of an
alkaline phenol-aldehyde resole having a
phenol to aldehyde mole ratio of 1:1.5 to
1:3.0, and a phenol to alkali mole ratio of
1:0.5 to 1:1.2; the phenol-aldehyde resole,
when dissolved in water at 45 to 50% by
weight solids content in the presence of
sodium hydroxide at a phenol to sodium hydroxide mole ratio of 1:1, having a viscosity of 1000 to 5000 centipoise at 20"C, and (B) a curing agent therefor.
The invention also provides a method of making a foundry mould or core which method comprises forming a mixture of granular refractory material and an aqueous binder composition which comprises: (A) alkaline phenol-aldehyde resin comprising: (i) 40 te 95% by weight, based on the
weight of the solids components of resin
A, of an alkaline phenol-aldehyde resole
having a phenol to aldehyde mole ratio of
1:2 to 1:3, and a phenol to alkali mole
ratio of 1:0.5 to 1:1.2; the phenol-al
dehyde resole, when dissolved in water at
45 to 50% by weight solids content in the
presence of sodium hydroxide at a phenol
to sodium hydroxide mole ratio of 1:1,
having a viscosity of 50 to 350 centipoise
at 20"C, and (ii) 5 to 60% by weight, based on the weight
of the solids components of resin A, of an
alkaline phenol-aldehyde resole having a
phenol to aldehyde mole ratio of 1:1.5 to
1:3.0, and a phenol to alkali mole ratio of
1:0.5 to 1:1.2; the phenol-aldehyde resole,
when dissolved in water at 45 to 50% by
weight solids content in the presence of
sodium hydroxide at a phenol to sodium
hydroxide mole ratio of 1:1, having a vis
cosity of 1000 to 5000 centipoise at 20"C, and (B) a curing agent therefor, forming the mixture, and allowing the mixture to cure.
We have found that fast cure speeds and high 24 hour strengths can be obtained-using in the binder composition a mixture of a relatively low molecular weight resole (Component (i)) together with a relatively highly condensed (high molecular weight) resole (Component (ii)).
The resin combination having a low molecular weight component is of acceptable viscosity for the foundry industry. Further, using the binder composition according to the present invention sufficient mould or core strengths can be obtained at low resin addition levels thus keeping costs down.
In particular, the present invention provides binder compositions based on sodium alkaline phenol-aldehyde resoles, which do not suffer from the poor strength characteristics and high addition levels of prior art resins based on this alkali. Rather, according to the present invention, there can be provided foundry binder compositions which develop high strength at low addition levels using the relatively cheap sodium hydroxide as the sole or major alkaline component of the resin. It should however also be appreciated that the resins used according to the present invention may alternatively comprise potassium hydroxide as the sole or major alkaline component of the resin.While, unless there is a major proportion of sodium hydroxide based resin also present, this may represent little cost saving over the prior art highly condensed resins based on potassium hydroxide, the present invention does provide greater flexibility of resin formulation within viscosities acceptable to the foundry industry.
The binder composition according to the present invention preferably contains the high molecular weight resole (Component (ii)) in minor amount. Most preferably the binder composition contains 60 to 90% by weight, based on the weight of the solids components of
Resin A, of Component (i) and 10 to 40% by weight, based on the weight of the solid components of Resin A, of Component (ii).
The alkaline phenol-aldehyde resoles used according to the present invention may be obtained by forming the phenol-aldehyde resole in the presence of the appropriate alkali or by dissolving the phenol-aldehyde resole in a solution of the alkali. For both Component (i) and Component (ii), the phenol to alkali mole ratio in the binder composition according to the invention is 1:0.5 to 1:1.2.
The viscosities of the two resole components are however referred to the resoles when dissovled in water at 45 to 50% by weight solids content in the presence of sodium hydroxide at a phenol to sodium hydroxide mole ratio of 1:1. For the low molecular weight component, Component (i), this is 50 to 350 centipoise, preferably 80 to 200, centipoise at 20"C. For the high molecular weight component, Component (ii), this viscosity is 1000 to 5000 centipoise, preferably 1000 to 3000 centipoise, at 20"C.
The amounts of the two resins used are determined by their properties (aldehyde to phenol ratio, degree of condensation etc.).
High molecular weight resoles having an aldehyde to phenol mole ratio above 2.6:1 are not preferred as they tend to have excess of free formaldehyde in the resin. However, it is generally desirable for promoting increased strength and cure speed for the low molecular weight, Component (i), used in the blend to have a relatively high aldehyde to phenol ratio.
Generally there is used a blend in which the higher molecular weight component, Component (ii), has a lower aldehyde to phenol ratio than the lower molecular weight component.
The solids content of the binder composition according to the invention will depend upon its composition, for example the amounts of high and low molecular weight resins used, their alkali content, etc. The solids content should preferably be as high as possible within the viscosity constraints. Generally the solids content of the binder composition will be in the range 45 to 65% by weight.
Generally speaking the phenol used in the resoles used according to the present invention will be unsubstituted phenol and the al dehyde used will be formaldehyde, whether monomeric or oligomeric. These materials are generally speaking readily available and cheaper than other materials. If desired though a substituted phenol or a higher aldehyde could be used.
Also, as mentioned above, there may be used as alkali in, one or both of the resole components, sodium hydroxide and/or potassium hydroxide. Preferably though the sole alkali used will be sodium hydroxide. Accordingly, a preferred aqueous foundry binder composition according to the invention comprises: (A) a sodium alkaline phenol-formaldehyde resin comprising: (i) 40 to 95%, more preferably 60 to 90%,
by weight, based on the weight of the
solids components of Resin A, of a so
dium alkaline phenol-formaldehyde resole
having a phenol to formaldehyde mole ra
tio of 1:2 to 1:3 and a phenol to sodium
hydroxide mole ratio of 1:0.5 to 1:1.2; the
phenol-formaldehyde resole, when dis
solved in water at 45 to 50% by weight
solids content in the presence of sodium
hydroxide at a phenol to sodium hydroxide
mole ratio of 1:1, having a viscosity of 50
to 350 centipoise, more preferably 80 to
200 centipoise, at 20"C, and (ii) 5 to 60%, more preferably 10 to 40%, by
weight, based on the weight of the solids
components of Resin A, of a sodium alkal
ine phenol-formaldehyde resole having a
phenol to formaldehyde mole ratio of 1:1.5
to 1:3.0, and a phenol to sodium hydrox
ide ratio of 1:0.5 to 1:1.2; the phenol
formaldehyde resole, when dissolved in
water at 45 to 50% by weight solids con
tent in the presence of sodium hydroxide
at a phenol to sodium hydroxide mole ratio
of 1:1, having a viscosity of 1000 to 5000
centipoise, more preferably 1000 to 3000
centipoise, at 20"C, and (B) a curing agent therefor.
Preferably the foundry binder composition according to the present invention will, in known manner, also contain at least one silane to improve strength. Suitably the silane is used in an amount of up to 3%, e.g. 0.05 to 3%, by weight based on the weight of the binder composition. Suitable silanes are alkali stable silanes, typically y-aminopropyltriethoxy- silane.
The curing agent used in the binder composition according to the present invention may be an ester. Such esters include esters of short and medium chain, e.g. Ct to CtO-alkyl mono- or poly- alcohols, with short or medium chain, e.g. Ct to C10-, carboxylic acids such as for example methly or ethyl formate, acetate, propionate or ethylene glycol monoor diacetate, glycerol mono-, di- or triacetate.
There may also be used lactones, either alone or mixed with other esters or lactones, including butyro-, capro- or valerolactone. There may also be used as curing agent propylene carbonate.
The amount of curing agent used would generally depend upon the amount of alkali present. Usually there will be 10 to 50% by weight of curing agent based on the weight of the binder solution. It is desirable, for strength and speed of curing, that the curing agent used be readly miscible with the resin.
If the curing agent used is liquid, this may conveniently be introduced into a mixture of an aqueous solution of the resin solution and the granular refractory material prior to moulding. If the curing agent is readily vaporisable, then it may be introduced by blowing through preformed resin sand mixture as described in
European 0086615.
The preferred curing agents for high cure speed are those derived from low molecular weight acids and alcohols or butyrolactone or propylene carbonate.
The granular refractory material used according to the present invention can be any material conventionally used in the foundry industry. Most generally there will be used as granular refractory material a sand.
The invention is further illustrated in the following Examples. In the Examples, the strip time was the time taken to achieve a compression strength of 350 kPa.
EXAMPLE 1
There was prepared a first resin, Resin 1 A, as follows:
Phenol and 48% by weight sodium hydroxide solution were mixed in amounts corresponding to a molar ratio of phenol:sodium hydroxide of 1:1. The mixture was cooled to 50"C and 37% by weight formalin was added stepwise in an amount corresponding to a phenol:formaldehyde ratio of 1:2.6. The temperature of the reaction mixture was allowed to rise and later heating was applied to raise the temperature of the mixture to its boiling point. Water was distilled off from the mixture until it reached a specific gravity of 1.246 and then the mixture allowed to react until its viscosity at 20"C reached 130 centipoise. The resin was cooled and 0.4% by weight y-aminopropyltriethoxysilane was added.
There was also prepared a secnd resin, Resin 1B, using the same procedure as for Resin 1 A except that the amount of formalin added corresponded to a phenol:formaldehyde ratio of 1:2. Water was not distilled off and the reaction of the mixture was allowed to proceed until a viscosity of 21 60 centipoise at 20"C was reached. On cooling of the resin, there was added 0.4% by weight y-aminopropyltriethoxysilane.
Resins 1A and 1B were mixed in a ratio of 80:20 by weight. The solids content of the mixture was 47 to 48% by weight.
30009 Chelford 60 sand was divided into two equal parts. The first part was mixed with 459 of the mixture of Resins 1A and 1B for 1 minute. The second part was mixed with 13.59 glyceryl triacetate for 1 minute.
The two parts were then mixed together at high speed and turned out. Standard 5X5 cm test cores were then prepared.
The strip time was measured as 35 minutes and the compression strength after 24 hours was 4800-5200 kPa. According to this
Example there were used 0.70 to 0.72% by weight resin solids based on the weight of the sand.
EXAMPLE 2
There was prepared a first resin, Resin 2A, as follows:
Phenol (926.39) and 47% by weight sodium hydroxide solution (837.49) were mixed and the resulting solution was cooled to 50"C.
37% by weight formalin (1571.1g) was added stepwise and cooling was applied as necessary to prevent the reaction temperature exceeding 70"C. After the exotherm had abated, the solution was heated to boiling and boiled for 30 minutes. The solution was then cooled rapidly by adding water (3809) and with external cooling. At 60"C, 78% by weight paraformaldehyde (165.29) was added and allowed to dissolve at between 65 and 70"C. The solution was then heated to boiling and 300g distillate were removed. The remaining solution was then cooled rapidly to 65"C and 78% by weight paraformaldehyde (75.89) was added.After the paraformaldehyde had dissolved, the solution was heated to 90"C and condensed to a viscosity at 20"C of 145 centipoise. The resin this obtained was cooled rapidly and 0.4% by weight, based on the weight of the resin, ;,-aminopropyltriethoxysi- lane was added. The final resin had a specific gravity at 200C of 1.246 and a solids content of 49%.
There was also prepared a second resin,
Resin 2B, usign the same procedure as for
Resin 1B except that the phenol to formaldehyde ratio was 1:2.6. The solids content of the resin was adjusted to 45% by evaporation under reduced pressure. The final viscosity of
Resin 2B was 2500 centipoise at 20"C.
Resins 2A and 2B were blended in a ratio of 80:20 by weight.
Compression testing was carried out as in
Example 1 using glyceryl triacetate as curing agent. At a resin addition of 0.61% by weight (solid resin on sand) and 0.39% by weight curing agent (based on sand), the 24 hour compression strength was 4310 kPA. At a 0.75% resin addition and 0.45% curing agent, the 24 hour compression was 5560 kPa. In the latter case, the strip time was 30 minutes.
Claims (19)
1. An aqueous foundry binder composition which comprises: (A) alkaline phenol-aldehyde resin comprising: (i) 40 to 95% by weight, based on the
weight of the solids component of resin A,
of an alkaline phenol-aldehyde resole hav
ing a phenol to aldehyde mole ratio of 1:2
to 1:3, and a phenol to alkali mole ratio of
1:0.5 to 1:1.2, the phenol-aldehyde resole,
when dissolved in water at 45 to 50% by
weight solids content in the presence of
sodium hydroxide at a phenol to sodium
hydroxide mole ratio of 1:1, having a vis
cosity of 50 to 350 centipoise at 20"C, and (ii) 5 to 60% by weight, based on the weight
of the solids components of resin A, of an
alkaline phenol-aldehyde resole having a
phenol to aldehyde mole ratio of 1:1.5 to
1:3.0, and a phenol to alkali mole ratio of
1:0.5 to 1:1.2; the phenol-aldehyde resole,
when dissolved in water at 45 to 50% by
weight solids content in the presence of
sodium hydroxide at a phenol to sodium
hydroxide mole ratio of 1:1, having a vis
cosity of 1000 to 5000 centipoise at 20"C, and (B) a curing agent therefor.
2. A composition according to claim 1 wherein the alkali used is sodium hydroxide.
3. A composition according to claim 1 or 2 which contains 60 to 90% by weight, based on the weight of the solids components of Resin A, of Component (i) and 10 to 40% by weight, based on the weight of the solid components of Resin A, of Component (ii).
4. A composition according to any one of the preceding claims wherein Component (i), when dissolved in water at 45 to 50% by weight solids content in the presence of sodium hydroxide at a phenol to sodium hydroxide mole ratio of 1:1, has a viscosity of 80 to 200 centipoise at 20"C.
5. A composition according to any one of the preceding claims wherein Component (ii), when dissolved in water at 45 to 50% by weight solids content in the presence of sodium hydroxide at a phenol to sodium hydroxide mole ratio of 1:1, has a viscosity of 1000 to 3000 centipoise at 20"C.
6. A composition according to any one of the preceding claims wherein the phenol used is unsubstituted phenol and the aldehyde used is monomeric or oligomeric formaldehyde.
7. A composition according to any one of the preceding claims which contains up to 3% by weight, based on the weight of the composition, of an alkali stable silane.
8. A composition according to any one of the preceding claims wherein the curing agent used is an ester of a C1 to C1O-alkyi mono- or poly- alcohol with a C, to C10 carboxylic acid, a lactone or propylene carbonate.
9. A composition according to any one of the preceding claims which contains 10 to 50% by weight of curing agent based on the weight of the binder composition.
10. A composition according to claim 1 substantially as described in any one of the
Examples.
11. A method of making a foundry mould or core which method comprises forming a mixture of granular refractory material and an aqueous binder composition which comprises: (A) alkaline phenol-aldehyde resin comprising: (i) 40 to 95% by weight, based on the
weight of the solids components of resin
A, of an alkaline phenol-aldehyde resole
having a phenol to aldehyde mole ratio of
1:2 to 1:3, and a phenol to alkali mole
ratio of 1:0.5 to 1:1.2; the phenol-al
dehyde resole, when dissolved in water at
45 to 50% by weight solids content in the
presence of sodium hydroxide at a phenol
to sodium hydroxide mole ratio of 1:1,
having a viscosity of 50 to 350 centipoise
at 20"C, and (ii) 5 to 60% by weight, based on the weight
of the solids components of resin A, of an
alkaline phenol-aldehyde resole having a
phenol to aldehyde mole ratio of 1:1.5 to
1:3.0, and a phenol to alkali mole ratio of
1:0.5 to 1:1.2; the phenol-aldehyde resole,
when dissolved in water at 45 to 50% by
weight solids content in the presence of
sodium hydroxide at a phenol to sodium
hydroxide mole ratio of 1:1, having a vis
cosity of 1000 to 5000 centipoise at 20"C, and (B) a curing agent therefor, forming the mixture, and allowing the mixture to cure.
12. A method according to claim 11 wherein the alkali used is sodium hydroxide.
13. A method according to claim 11 or 12 wherein there is used 60 to 90% by weight, based on the weight of the solids components of Resin A, of component (i) and 10 to 40% by weight, based on the weight of the solid components of Resin A, of Component (ii).
14. A method according to any one of claims 11 to 13 wherein Component (i), when dissolved in water at 45 to 50% by weight solids content in the presence of sodium hydroxide at a phenol to sodium hydroxide mole ratio of 1:1, has a viscosity of 80 to 200 centipoise at 20"C.
15. A method according to any one of claims 11 to 14 wherein Component (ii), when dissolved in water at 45 to 50% by weight solids content in the presence of sodium hydroxide at a phenol to sodium hydroxide mole ratio of 1:1, has a viscosity of 1000 to 3000 centipoise at 200C.
16. A method according to any one of claims 11 to 15 wherein the phenol used is unsubstituted phenol and the aldehyde used is monomeric or oligomeric formaldehyde.
17. A method according to any one of claims 11 to 16 wherein the composition contains up to 3% by weight, based on the weight of the composition, of an alkali stable silane.
18. A method according to any one of claim 11 to 17 wherein the curing agent used is an ester of a C1 to C10-alkyl mono- or polyalcohol with a C1 to C10-carboxylic acid, a lactone or propylene carbonate.
19. A method according to any one of claims 11 to 18 wherein there is used 10 to 50% by weight of curing agent based on the weight of the binder composition.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08516669A GB2177408A (en) | 1985-07-02 | 1985-07-02 | Foundry binder compositions |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08516669A GB2177408A (en) | 1985-07-02 | 1985-07-02 | Foundry binder compositions |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB8516669D0 GB8516669D0 (en) | 1985-08-07 |
| GB2177408A true GB2177408A (en) | 1987-01-21 |
Family
ID=10581639
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08516669A Withdrawn GB2177408A (en) | 1985-07-02 | 1985-07-02 | Foundry binder compositions |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2177408A (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0336534A1 (en) * | 1988-04-08 | 1989-10-11 | Acme Resin Corporation | Compositions for foundry molding processes utilizing reclaimed sand |
| EP0398463A3 (en) * | 1989-04-27 | 1992-01-22 | Borden, Inc. | Ester hardeners for phenolic resin binder systems |
| GB2255341A (en) * | 1991-02-21 | 1992-11-04 | Foseco Int | Alkaline resole phenolic resin compositions |
| US5190993A (en) * | 1988-04-08 | 1993-03-02 | Borden, Inc. | Process to enhance the tensile strength of reclaimed sand bonded with ester cured alkaline phenolic resin using an aminosilane solution |
| US5234973A (en) * | 1988-04-08 | 1993-08-10 | Acme Resin Corporation | Compositions for foundry molding processes utilizing reclaimed sand |
| US5238976A (en) * | 1990-06-15 | 1993-08-24 | Borden, Inc. | Process to enhance the tensile strength of reclaimed sand bonded with ester cured alkaline phenolic resin |
-
1985
- 1985-07-02 GB GB08516669A patent/GB2177408A/en not_active Withdrawn
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0336534A1 (en) * | 1988-04-08 | 1989-10-11 | Acme Resin Corporation | Compositions for foundry molding processes utilizing reclaimed sand |
| US5082876A (en) * | 1988-04-08 | 1992-01-21 | Borden, Inc. | Compositions for foundry molding processes utilizing reclaimed sand |
| US5190993A (en) * | 1988-04-08 | 1993-03-02 | Borden, Inc. | Process to enhance the tensile strength of reclaimed sand bonded with ester cured alkaline phenolic resin using an aminosilane solution |
| US5234973A (en) * | 1988-04-08 | 1993-08-10 | Acme Resin Corporation | Compositions for foundry molding processes utilizing reclaimed sand |
| EP0398463A3 (en) * | 1989-04-27 | 1992-01-22 | Borden, Inc. | Ester hardeners for phenolic resin binder systems |
| US5238976A (en) * | 1990-06-15 | 1993-08-24 | Borden, Inc. | Process to enhance the tensile strength of reclaimed sand bonded with ester cured alkaline phenolic resin |
| GB2255341A (en) * | 1991-02-21 | 1992-11-04 | Foseco Int | Alkaline resole phenolic resin compositions |
| GB2255341B (en) * | 1991-02-21 | 1994-06-01 | Foseco Int | Alkaline resole phenolic resin compositions |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8516669D0 (en) | 1985-08-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |