EP3056296A1 - Mélange pour liant pour sable de fonderie - Google Patents

Mélange pour liant pour sable de fonderie Download PDF

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Publication number
EP3056296A1
EP3056296A1 EP16154978.7A EP16154978A EP3056296A1 EP 3056296 A1 EP3056296 A1 EP 3056296A1 EP 16154978 A EP16154978 A EP 16154978A EP 3056296 A1 EP3056296 A1 EP 3056296A1
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EP
European Patent Office
Prior art keywords
weight
parts
mixture
alkyl ester
phosphate
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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Application number
EP16154978.7A
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German (de)
English (en)
Inventor
Giorgio Zennaro
Gianni Claudio STROPPOLO
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Cavenaghi SpA
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Cavenaghi SpA
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Publication date
Application filed by Cavenaghi SpA filed Critical Cavenaghi SpA
Publication of EP3056296A1 publication Critical patent/EP3056296A1/fr
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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

Definitions

  • the present invention relates to synthetic resin-based systems, such as furan resins, to be used, in combination with suitable curing agents, as binders in mixtures with silica sand or other granular masses, for the production of foundry moulds and cores.
  • the aforesaid foundry binder systems normally consist of two or more components which are mixed with sand or other granular masses in order to subsequently produce the shapes or cores into which or around which the molten metal will be poured.
  • furan no-bake binder systems such as, for example, those described in pages 30-34 of the publication " No-bake cores and molds", published in 1980 by the American Foundrymen's Society , and incorporated herein for reference.
  • binder systems consist of two liquids (furan resin and acidic curing agent) which, when added to the sand, produce, with no heating needed, cores and moulds which are suitable for the production of ferrous and non-ferrous metal castings.
  • the furan resin is substantially constituted of furfuryl alcohol varyingly condensed with formaldehyde, and - if necessary - modified with ureic, melamine, and phenolic resins and various additives.
  • the condensation reaction normally takes place in the presence of an acidic catalyst, such as, for example, acetic acid.
  • an acidic catalyst such as, for example, acetic acid.
  • Furan resins used in the no-bake systems are described, for example, in pages B320-6 to B320-15 of the publication " Manuel des sables à prise chimique", published by the Centre Technique des Industries de la Fonderie in 1993 , incorporated herein for reference. Furan resins are also described in US2343972 , US4634723 , and US 5459183 , incorporated herein for reference.
  • the acidic curing agent has the function of creating the strongly acidic environment (usually below pHl) needed to cause the sand/resin mixture to cure.
  • the acidic curing agent usually consists of a hydroalcoholic or aqueous solution of one or more sulphonic acids, if necessary, mixed with other organic or inorganic acids.
  • sulphonic acids are benzenesulphonic acid, toluenesulphonic acid, xylene sulphonic acid, cumene sulphonic acid, phenolsulphonic acid, and methanesulphonic acid, or mixtures thereof.
  • toluenesulphonic acid is by far the most used.
  • the curing agent consists of orthophosphoric acid, either alone or mixed with sulphonic acids.
  • Orthophosphoric acid brings drawbacks related to the formation - as a result of the casting heat - of non-volatile compounds, which accumulate in the sand and lower the refractoriness during subsequent reuse.
  • Another component of the inorganic curing agents is sulphuric acid, which is almost always present in sulphonic acids in small amounts, as the residue of the sulphonation process.
  • sulphuric acid is intentionally added to curing agents to increase the strength thereof. Sulphuric acid, however, is an often undesired component for both environmental reasons (unpleasant odours) and for reasons of quality in relation to highly critical castings.
  • Patent application WO 2012/080454A1 relates to a low-emission cold-curing resin for the foundry industry with a furfuryl alcohol content of below 25%, a formaldehyde conversion product content of 40% or above, and an assumed free formaldehyde content of below 0.5%, which uses an organic acid with a pKa of 2.5 or above, and/or the salts thereof, as an acidic catalyst for condensation.
  • the aforesaid alkyl esters of phosphorous acid and/or phosphoric acid may have a pKa below 2.5. They are preferably C 1 -C 8 alkyl esters, even more preferably diesters, such as dimethyl phosphate, diethyl phosphate, dipropyl phosphate, dibutyl phosphate, bis(2-ethylhexyl) phosphate, dimethyl phosphite, diethyl phosphite, dipropyl phosphite and dibutyl phosphite; particularly preferred esters have proved to be dibutyl phosphite, dibutyl phosphate, and bis(2-ethylhexyl) phosphate.
  • diesters such as dimethyl phosphate, diethyl phosphate, dipropyl phosphate, dibutyl phosphate, bis(2-ethylhexyl) phosphate, dimethyl phosphite
  • one aim of the present invention consists, therefore, of the use of at least one alkyl ester of phosphorous acid and/or phosphoric acid and/or a salt thereof as an acidic catalyst for the manufacture of foundry binder mixtures, for example those of the 'no-bake' type.
  • a further aim of the invention also consists of a mixture usable as a foundry binder, for example of the no-bake type, containing:
  • Formaldehyde conversion products is understood as the products resulting from the condensation between formaldehyde and furfuryl alcohol and, optionally, components other than furfuryl alcohol and/or products deriving from the condensation between formaldehyde and one or more compounds other than furfuryl alcohol.
  • the aforesaid compounds other than furfuryl alcohol can be: urea, melamine, phenol or derivatives thereof; the phenol derivatives are preferably C 6 -C 25 organic compounds containing at least one phenolic radical or at least one benzene radical with two, three or four hydroxyl groups, such as diphenols (for example resorcinol), alkylphenols (for example ortho-cresol, meta-cresol and/or para-cresol), bisphenols (such as 4,4'-isopropylidenediphenol).
  • diphenols for example resorcinol
  • alkylphenols for example ortho-cresol, meta-cresol and/or para-cresol
  • bisphenols such as 4,4'-isopropylidenediphenol
  • the said mixture has a water content no greater than 20% by weight and, preferably, no greater than 15% by weight.
  • the mixture has the following composition by weight:
  • the one alkyl ester of phosphorous acid aaid/or phosphoric acid and/or a salt thereof is present in the mixture in quantities ranging from between 0.1% and 5.0% by weight, and preferably between 0.3% and 2.0% by weight, with respect to the weight of the mixture.
  • the alkyl ester of phosphorous acid and/or phosphoric acid may be chosen from dibutyl phosphite, dibutyl phosphate and bis(2-ethylhexyl phosphate).
  • the mixture may contain further components, such as, for example:
  • a further aim of the present invention consists of a process for the production of the aforesaid mixture usable as a foundry binder, wherein a mixture containing:
  • formaldehyde is used in the form of paraformaldehyde, in particular paraformaldehyde with a 89-91% by-weight content of formaldehyde.
  • the mixture thus obtained is then cooled to a temperature ranging from 55 to 65°C and subjected to a further treatment to lower the free formaldehyde content to a value below 0.5%.
  • a phenolic compound preferably chosen from among C 6 -C 25 organic compounds containing at least one phenolic radical or at least one benzene radical with two, three or four hydroxyl groups, such as diphenols (for example resorcinol), alkylphenols (for example cresoles or xylenols), bisphenols (such as 4,4'-isopropylidenediphenol).
  • the mixture Upon reaching a free formaldehyde content below 0.5% by weight, the mixture is cooled to below 35°C, additivised with compounds able to increase adhesion between the binder system and the grains of sand, such as - for example - silanes, preferably including 3-aminopropyl triethoxy silane, 3-(Diethoxymethyl-silyl)propylamine), 3-glycidoxypropyltrimethoxysilane and any additives capable of reducing viscosity (for example, ethanol or benzyl alcohol) or the reactivity of the sand/resin/curing agent mixture (for example glycols).
  • silanes preferably including 3-aminopropyl triethoxy silane, 3-(Diethoxymethyl-silyl)propylamine), 3-glycidoxypropyltrimethoxysilane and any additives capable of reducing viscosity (for example, ethanol or benzyl alcohol) or the reactivity of the
  • a further aim of the present invention consists of a foundry binder system, preferably of the no-bake type, comprising or consisting of a binder mixture compliant with the description set out above and an acidic curing agent.
  • the acidic curing agent may be an aqueous or hydroalcoholic solution with a pH below 2, preferably below 1, at ambient temperature.
  • the aforesaid solution may contain one or more sulphonic acids, such as - for example - benzenesulphonic acid, toluenesulphonic acid, xylene sulphonic acid, cumene sulphonic acid, phenolsulphonic acid, methanesulphonic acid, if necessary, mixed with other organic or inorganic acids.
  • the aforesaid solution may also contain orthophosphoric acid, either alone or mixed with sulphonic acids.
  • the binder system may be composed of 0.2-0.8 parts by weight acidic curing agent and 0.6-1.5 parts by weight binder mixture, preferably from 0.3-0.6 parts by weight acidic curing agent and 0.7-1.2 parts by weight binder mixture.
  • the cores and/or moulds according to the present invention may be composed of 0.2-0.8 parts by weight acidic curing agent, 0.6-1.5 parts by weight binder mixture, and 80-120 parts by weight sand and/or other refractory material; preferably, such cores and/or moulds contain 100 parts by weight sand and/or other refractory material, 0.3-0.6 parts by weight acidic curing agent, and 0.7-1.2 parts by weight binder mixture.
  • One aim of the present invention also consists of the procedure for the production of foundry cores and/or moulds, wherein an acidic curing agent is mixed with sand and/or another refractory material, at ambient temperature, and with a binder mixture compliant with the description set out above.
  • an acidic curing agent is mixed with sand and/or another refractory material, at ambient temperature, and with a binder mixture compliant with the description set out above.
  • 80-120 parts by weight sand are mixed with 0.2-0.8 parts by weight said acidic curing agent and with 0.6-1.5 parts by weight binder mixture; still more preferably, approximately 100 parts by weight sand and/or other refractory material are mixed 0.3-0.6 parts by weight acidic curing agent and 0.7-1.2 parts by weight binder mixture.
  • the aims of the present invention also include the foundry cores and/or moulds obtainable according to the said procedure.
  • 'ambient temperature' is understood as a temperature ranging approximately from 0 ° to + 40 °C, preferably from +15 to + 30 °C, depending on the season and the geographic position (latitude, altitude, etc.) of the foundry.
  • the free formaldehyde content was determined using the AN006.6 method, which is annexed hereto, and based on the reaction of formaldehyde with sodium sulphite. This method is taken from the text by Walker, J. Frederic, Formaldehyde, Third Edition, Robert E. Krieger Publishing Corporation and the EN ISO 11402:2004 method, incorporated herein for reference.
  • Example 1 Resin NS-1A (not compliant with the invention).
  • the two resins were used as the basis for the synthesis of the resins according to the invention.
  • the catalyst was changed [(raw material e)] and - where necessary - the type and amount of the raw material d) was adjusted to maintain the pH during condensation at a value above 4.2, as was the quantity of water c), in order to maintain the reflux temperature at 120-125°C.
  • the processing instructions remain unchanged.
  • composition of the mixtures :
  • standard + GF + bars were prepared with a 5 cm 2 rupture section.
  • the bending strength of the aforesaid bars was measured after 3, 5, and 24 hours of stay at a temperature of 18-19°C from the time the mixture is unloaded from the mixer using a BENET device (COE model).

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Mold Materials And Core Materials (AREA)
EP16154978.7A 2015-02-13 2016-02-10 Mélange pour liant pour sable de fonderie Withdrawn EP3056296A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
ITMI20150206 2015-02-13

Publications (1)

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EP3056296A1 true EP3056296A1 (fr) 2016-08-17

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3085724A1 (fr) * 2015-04-24 2016-10-26 Cavenaghi SPA Système de liant de fonderie avec une faible teneur en formaldéhyde et son procédé d'obtention
CN116274851A (zh) * 2022-12-15 2023-06-23 江苏华岗材料科技发展有限公司 一种铸造用粘合剂及制备方法

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2343972A (en) 1943-02-24 1944-03-14 Harvel Res Corp Novel furfuryl alcohol-formaldehyde acid condensation resinous product and method for preparing the same
US3227564A (en) * 1961-01-31 1966-01-04 Catalin Ltd Foundry moulding process
US3734936A (en) * 1971-02-03 1973-05-22 Quaker Oats Co Process of producing a foundry core composition
US3779955A (en) * 1972-01-31 1973-12-18 Resitron Corp Non-burning resinous compounds and structures prepared from furan resins
US4111253A (en) * 1972-08-21 1978-09-05 The White Sea & Baltic Company Limited Foundry processes and compositions
JPS57139443A (en) * 1981-02-20 1982-08-28 Hitachi Ltd Molding method for mold
US4634723A (en) 1984-03-31 1987-01-06 Rutgerswerke Aktiengesellschaft Furfuryl alcohol binders, methods for their production and use
US5096983A (en) * 1990-08-02 1992-03-17 Borden, Inc. Method for making a phenolic resole resin composition having extended work life
EP0540837A1 (fr) * 1991-11-07 1993-05-12 Bakelite AG Liant modifié avec de la lignine
US5459183A (en) 1993-05-19 1995-10-17 Schuller International, Inc. Low VOC furan resins and method of reducing VOCS in furan resins
WO2012080454A1 (fr) 2010-12-16 2012-06-21 Hüttenes-Albertus Chemische Werke GmbH Liant durcissant à froid à faibles émissions pour l'industrie de la fonderie
DE102012201971A1 (de) * 2012-02-09 2013-08-14 Hüttenes-Albertus Chemische Werke GmbH Cold-Box-Bindemittelsysteme und Mischungen zur Verwendung als Additive für solche Bindemittelsysteme
CN103113547B (zh) * 2013-03-06 2014-11-05 苏州兴业材料科技股份有限公司 改性铸造用呋喃树脂的制备方法

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2343972A (en) 1943-02-24 1944-03-14 Harvel Res Corp Novel furfuryl alcohol-formaldehyde acid condensation resinous product and method for preparing the same
US3227564A (en) * 1961-01-31 1966-01-04 Catalin Ltd Foundry moulding process
US3734936A (en) * 1971-02-03 1973-05-22 Quaker Oats Co Process of producing a foundry core composition
US3779955A (en) * 1972-01-31 1973-12-18 Resitron Corp Non-burning resinous compounds and structures prepared from furan resins
US4111253A (en) * 1972-08-21 1978-09-05 The White Sea & Baltic Company Limited Foundry processes and compositions
JPS57139443A (en) * 1981-02-20 1982-08-28 Hitachi Ltd Molding method for mold
US4634723A (en) 1984-03-31 1987-01-06 Rutgerswerke Aktiengesellschaft Furfuryl alcohol binders, methods for their production and use
US5096983A (en) * 1990-08-02 1992-03-17 Borden, Inc. Method for making a phenolic resole resin composition having extended work life
EP0540837A1 (fr) * 1991-11-07 1993-05-12 Bakelite AG Liant modifié avec de la lignine
US5459183A (en) 1993-05-19 1995-10-17 Schuller International, Inc. Low VOC furan resins and method of reducing VOCS in furan resins
WO2012080454A1 (fr) 2010-12-16 2012-06-21 Hüttenes-Albertus Chemische Werke GmbH Liant durcissant à froid à faibles émissions pour l'industrie de la fonderie
DE102012201971A1 (de) * 2012-02-09 2013-08-14 Hüttenes-Albertus Chemische Werke GmbH Cold-Box-Bindemittelsysteme und Mischungen zur Verwendung als Additive für solche Bindemittelsysteme
CN103113547B (zh) * 2013-03-06 2014-11-05 苏州兴业材料科技股份有限公司 改性铸造用呋喃树脂的制备方法

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
"Manuel des sables a prise chimique", 1993, CENTRE TECHNIQUE DES INDUSTRIES DE LA FONDERIE, pages: B320 - 6,B320-1
WALKER, J. FREDERIC: "Formaldehyde", PUBLISHING CORPORATION

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3085724A1 (fr) * 2015-04-24 2016-10-26 Cavenaghi SPA Système de liant de fonderie avec une faible teneur en formaldéhyde et son procédé d'obtention
EP3085724B1 (fr) 2015-04-24 2019-06-05 Cavenaghi SPA Système de liant de fonderie avec une faible teneur en formaldéhyde et son procédé d'obtention
EP3530685A1 (fr) * 2015-04-24 2019-08-28 Cavenaghi SPA Système de liant de fonderie avec une faible teneur en formaldéhyde et son procédé d'obtention
CN116274851A (zh) * 2022-12-15 2023-06-23 江苏华岗材料科技发展有限公司 一种铸造用粘合剂及制备方法
CN116274851B (zh) * 2022-12-15 2023-10-20 江苏华岗材料科技发展有限公司 一种铸造用粘合剂及制备方法

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