EP3934826A1 - Piégeur de formaldéhyde pour systèmes de liants - Google Patents

Piégeur de formaldéhyde pour systèmes de liants

Info

Publication number
EP3934826A1
EP3934826A1 EP20712465.2A EP20712465A EP3934826A1 EP 3934826 A1 EP3934826 A1 EP 3934826A1 EP 20712465 A EP20712465 A EP 20712465A EP 3934826 A1 EP3934826 A1 EP 3934826A1
Authority
EP
European Patent Office
Prior art keywords
group
binder system
molding material
formaldehyde
material mixture
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.)
Pending
Application number
EP20712465.2A
Other languages
German (de)
English (en)
Inventor
Annika KLOSE
Daniel WINKELHAUS
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huettenes Albertus Chemische Werke GmbH
Original Assignee
Huettenes Albertus Chemische Werke GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Huettenes Albertus Chemische Werke GmbH filed Critical Huettenes Albertus Chemische Werke GmbH
Publication of EP3934826A1 publication Critical patent/EP3934826A1/fr
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
    • B22C1/16—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents
    • B22C1/20—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents
    • B22C1/22—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents of resins or rosins
    • B22C1/2233—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by the use of binding agents; Mixtures of binding agents of organic agents of resins or rosins obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
    • B22C1/2246—Condensation polymers of aldehydes and ketones
    • B22C1/2253—Condensation polymers of aldehydes and ketones with phenols
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/40—High-molecular-weight compounds
    • C08G18/54—Polycondensates of aldehydes
    • C08G18/542—Polycondensates of aldehydes with phenols
    • 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
    • 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
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/08—Processes
    • C08G18/0838—Manufacture of polymers in the presence of non-reactive compounds
    • C08G18/0842—Manufacture of polymers in the presence of non-reactive compounds in the presence of liquid diluents
    • C08G18/0847—Manufacture of polymers in the presence of non-reactive compounds in the presence of liquid diluents in the presence of solvents for the polymers
    • C08G18/0852—Manufacture of polymers in the presence of non-reactive compounds in the presence of liquid diluents in the presence of solvents for the polymers the solvents being organic
    • 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
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
    • C08G18/30—Low-molecular-weight compounds
    • C08G18/38—Low-molecular-weight compounds having heteroatoms other than oxygen
    • C08G18/3819—Low-molecular-weight compounds having heteroatoms other than oxygen having nitrogen
    • C08G18/3821—Carboxylic acids; Esters thereof with monohydroxyl compounds
    • 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
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
    • C08G18/72—Polyisocyanates or polyisothiocyanates
    • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
    • C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
    • C08G18/7657—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings
    • C08G18/7664—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups
    • 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
    • C08G18/00—Polymeric products of isocyanates or isothiocyanates
    • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
    • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
    • C08G18/72—Polyisocyanates or polyisothiocyanates
    • C08G18/74—Polyisocyanates or polyisothiocyanates cyclic
    • C08G18/76—Polyisocyanates or polyisothiocyanates cyclic aromatic
    • C08G18/7657—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings
    • C08G18/7664—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups
    • C08G18/7671—Polyisocyanates or polyisothiocyanates cyclic aromatic containing two or more aromatic rings containing alkylene polyphenyl groups containing only one alkylene bisphenyl group
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
    • C08J7/04—Coating
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/16—Nitrogen-containing compounds
    • C08K5/17—Amines; Quaternary ammonium compounds
    • C08K5/175—Amines; Quaternary ammonium compounds containing COOH-groups; Esters or salts thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/16—Nitrogen-containing compounds
    • C08K5/21—Urea; Derivatives thereof, e.g. biuret
    • 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
    • C08L61/14—Modified phenol-aldehyde condensates
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2375/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
    • C08J2375/04—Polyurethanes

Definitions

  • the present invention relates to a binder system, in particular for use in a method from the group consisting of the polyurethane cold box method and the polyurethane no-bake method; a molding material mixture containing this binder system; a method in which a binder system according to the invention is used; and articles from the group consisting of foundry molds and foundry cores.
  • the present invention further relates to the use of substances selected from the group consisting of amino acids and urea for the production of a binder system according to the invention or a molding material mixture according to the invention and the use of a binder system according to the invention or a molding material mixture according to the invention for the production of articles from the group consisting of foundry molds, Foundry cores and feeders.
  • cold-curing binder systems are often used to bind the basic mold material, forming polyurethane.
  • binder systems comprise two components, a polyol (usually dissolved in a solvent) with at least two OH groups in the molecule (polyol component) and a polyol isocyanate (dissolved in a solvent or solvent-free) with at least two isocyanate groups in the Molecule (polyisocyanate component).
  • the polyol component is usually a phenolic resin dissolved in a solvent.
  • the polyol component is therefore referred to below as a phenolic resin component.
  • the two binder components that are used to produce a molding material mixture The basic material is added and mixed with it, react in the molded molding material mixture in a polyaddition reaction to form a polyurethane binder.
  • the curing of the binder system takes place in the presence of basic catalysts, preferably in the form of tertiary amines, which are introduced into the molding tool after the molding of the molding mixture with a carrier gas (polyurethane cold box process) or which are introduced into the molding tool before molding of the molding mixture as Solution are added (polyurethane no-bake method).
  • basic catalysts preferably in the form of tertiary amines
  • DE 10244442 A1 discloses a preservative with reduced formaldehyde emission, which at least one formal and at least one emission-reducing additive selected, among others. of urea and amino acids, e.g. for the preservation of coolants, lubricants, fuels, lacquers, dispersions or water-based paints.
  • DE 102 44 442 A1 relates to a technical field that is very far removed from that of the present application.
  • DE 23 49 598 B discloses a binder based on phenol-formaldehyde condensation products, optionally with additions of resols and modifiers, and with a content of hardeners, for use in hot-curing molding compounds, in particular in foundry molding compounds using the mask molding process , characterized in that the phenol-formaldehyde condensation product has an additional content of aminocar- having bonic acids.
  • the amino acid is already added during the manufacture of the phenol-formaldehyde condensation product, so that the amino acid “condenses”, ie is incorporated into the phenol-formaldehyde condensation product.
  • the amino acid is therefore no longer available (or only in a relatively small amount) as a formaldehyde scavenger during the production of feeders, foundry cores and foundry molds.
  • the purpose of adding amino acids to the binder according to DE 23 49 598 B is to improve the water solubility of the binder.
  • the reduction of formaldehyde emissions does not play a role in the disclosure of DE 23 49 598 B.
  • the production of feeders, foundry cores and foundry molds includes steps downstream of the hardening of the binder system, in which moldings produced using the polyurethane cold box process or the polyurethane no-bake process are exposed to an elevated temperature .
  • foundry molds and foundry cores are preferably used, the surface of which has areas in which a coating is arranged which comprises particles of one or more refractory materials.
  • This coating forms a surface of the mold or core that comes into contact with a molten metal during the casting process.
  • Such a coating is commonly referred to as a size or size coating.
  • This coating acts as a boundary and / or barrier layer against the cast metal, and serves, among other things, to suppress mechanisms of casting defects at the interface between metal and core or mold, and / or for the targeted use of metallurgical effects.
  • coatings in foundry technology should primarily fulfill the following functions known to those skilled in the art:
  • Ready-to-use compositions for the production of coatings for foundry molds and foundry cores are usually suspensions of fine-grained, refractory to highly refractory inorganic materials (refractories) in a carrier liquid (e.g. water, alkanols, or mixtures of water and one or more alkanols), further constituents often being suspended or dissolved in the carrier liquid.
  • a carrier liquid e.g. water, alkanols, or mixtures of water and one or more alkanols
  • the size composition is applied to the corresponding surface areas of a molding, and then the carrier liquid is removed by thermal treatment, with a coating being formed.
  • the carrier liquid is usually removed at a temperature above 40.degree. C., preferably in the range from 50.degree. C. to 200.degree. At these temperatures, moldings which have been produced from a molding material mixture comprising a binder system which cures to form a polyurethane emit significant amounts of formaldehyde. Such emissions represent
  • the causes of the emissions of formaldehyde to be reduced according to the invention are in particular the following two sources:
  • Formaldehyde which is released when the risers, foundry cores and foundry molds are exposed to thermal stress through at least partial decomposition of the binder (polyurethane formed from the phenolic resin of the phenolic resin component (i) and the polyisocyanate of the polyisocyanate component (ii)).
  • the present invention provides ways and means to reduce emissions of formaldehyde from both sources.
  • the object of the present invention is to reduce the emissions of formaldehyde, which are released in particular (but not only) under thermal stress from feeders, foundry cores and foundry molds made from a molding material mixture with a binder system comprising a phenolic resin component and a Polyisocyanate component have been produced.
  • this object is achieved by a binder system, in particular for use in a process from the group consisting of the polyurethane cold box process and the polyurethane no-bake process, the binder system comprising:
  • the concentration of the phenolic resins a) is 40% to 60%, preferably 45% to 60%, particularly preferably 48% to 55%
  • the concentration of the isocyanates c) is 60% to 100%; preferably 70% to 98%, particularly preferably 75% to 95%
  • components (i), (ii) and (iii) are spatially separated from one another.
  • the binder system according to the invention preferably consists of
  • the binder system according to the invention particularly preferably comprises or consists of
  • the stoichiometric ratio of isocyanate groups in the polyisocyanate component (ii) to hydroxyl groups in the phenolic resin component (i) is preferably in the range from 0.5 to 1.5, more preferably in the range from 0.6 to 1.4, more preferably in the range from 0.7 to 1.3, particularly preferably in the range from 0.8 to 1.2, very particularly preferably in the range from 0.9 to 1.1, especially preferably in the range from 0.95 to 1.05.
  • the phenolic resin component (i), the polyisocyanate component (ii) and the further component (iii) are separate from one another, ie they are in separate containers.
  • the addition reaction (polyurethane formation) between the phenolic resin of the phenolic resin component (i) and the polyisocyanate of the polyisocyanate component (ii) should only occur when the two components (i) and (ii) are in a molding material mixture with a molding base material and optionally others Components of the molding mixture to be produced have been mixed and this molding mixture has been molded.
  • substances e) selected from the group consisting of amino acids and urea are able to bind molecular formaldehyde with the formation of non-volatile reaction products, so they act as formaldehyde scavengers.
  • the structures of the resulting reaction products are known to the person skilled in the art.
  • substances e) selected from the group consisting of amino acids and urea methylolation of the amino groups of the amino acids or of the urea takes place.
  • this reaction takes place as follows:
  • the products formed in the process can enter into further condensation reactions, so that long-chain, possibly crosslinked, resin-like products with structures similar to formaldehyde-urea resins are formed.
  • component (iii) of the binder system according to the invention does not contain any formaldehyde
  • the aforementioned reaction of substances e) selected from the group consisting of amino acids and urea with formaldehyde only takes place when the substances contained in component (iii) of the binder system according to the invention e) selected from the group consisting of amino acids and urea come into contact with molecular formaldehyde.
  • component (iii) of the binder system according to the invention is combined with a phenolic resin component (i) which has a significant concentration of molecular formaldehyde (for details see below), or when a molded body produced from such a molding material mixture is exposed to thermal stress.
  • substances e) selected from the group consisting of urea and amino acids are able to reduce formaldehyde emissions very effectively. I.e. the reaction between substance e) present as a solid and the gaseous formaldehyde is surprisingly very efficient.
  • a binder system for the production of moldings, the phenolic resin component (i) of which has a very low concentration of molecular formaldehyde (for details see below), and the binder system is made by a process without the supply of heat the group consisting of the polyurethane cold box process and the polyurethane no bake process (for details see below).
  • the binder system is made by a process without the supply of heat the group consisting of the polyurethane cold box process and the polyurethane no bake process (for details see below).
  • moldings produced in this way also tend to release formaldehyde in the course of time, particularly when exposed to heat. This is bound to non-volatile reaction products by reaction with substances contained according to the invention in component (iii) of the binder system selected from the group consisting of amino acids and urea, so that the emission of formaldehyde is reduced.
  • the amino acids e) are preferably selected from the group consisting of alanine, glycine, isoleucine, methionine, proline, valine, histidine, phenylalanine, tryptophan, tyrosine, aspargin, glutamine, cysteine, methionine, serine, threonine, tyrosine, lysine , Arginine and histidine, particularly preferably from the group consisting of the group consisting of glycine, glutamine, alanine, valine and serine. Glycine is particularly preferred.
  • component (iii) the total concentration of substances e) selected from the group consisting of amino acids and urea is preferably 0.1% to 100%, preferably 10% to 80%, particularly preferably 15% to 60%, each based on the total mass of component (iii).
  • component (iii) of the binder system according to the invention consists of one or more substances e) selected from the group consisting of amino acids and urea.
  • component (iii) of the binder system according to the invention contains, in addition to one or more substances e) selected from the group consisting of amino acids and urea, one or more further constituents which are present in solid form at 25 ° C. and 101.325 kPa .
  • component (iii) contains besides
  • one or more other components from the group consisting of iron oxide, starch, corn cob granulate, wood flour, basic mold materials (e.g. quartz), graphite, magnesium oxide and spodumene.
  • component (iii) of the binder system according to the invention is thus a mixture comprising the above-mentioned constituents e) and f), or consisting of the above-mentioned constituents e) and f).
  • component (iii) of the binder system according to the invention are expediently selected from the usual constituents of molding mixtures (such as molding raw materials) and constituents of conventional additive mixtures for molding mixtures, e.g. Usual additive mixtures to avoid casting defects.
  • molding mixtures such as molding raw materials
  • additive mixtures e.g. Usual additive mixtures to avoid casting defects.
  • Such additive mixtures are known to those skilled in the art.
  • component (iii) of the binder system according to the invention is a mixture comprising or consisting of
  • one or more components that are contained in the molding material mixture to be produced for example a basic molding material.
  • substances e) selected from the group consisting of amino acids and urea as part of a mixture with one or more further constituents f), which are contained in the molding material mixture to be produced anyway, such as basic molding materials, facilitates the dosing and mixing of the component (iii ) during the production of the molding material mixture.
  • suitable molding raw materials reference is made to the statements in the context of the second aspect of the invention.
  • component (iii) of the binder system according to the invention is a mixture comprising or consisting of
  • one or more components of conventional additive mixtures for molding mixtures e.g. selected from the group consisting of iron oxide, starch, corn cob granules, wood flour, graphite, magnesium oxide, quartz and spodumene.
  • the proportion of components present in solid form at 25 ° C. and 101.325 kPa, including e) substances selected from the group consisting of amino acids and urea, is preferably 50% to 100%, preferably 75% to 100%, particularly preferably 85 % to 100%, based on the total mass of component (iii).
  • Component (iii) is preferably a solid or a homogeneous solid mixture, in particular in powder form or in granular form. In order to avoid the development of dust, it is preferred in some cases that component (iii) also contains small proportions of constituents which are present in liquid form at 25 ° C. and 101.325 kPa.
  • the solid constituents of component (iii) can be mixed with a liquid composition which corresponds to the composition of the phenolic resin component (i) of the binder system.
  • the proportion of constituents of component (iii) present in liquid form at 25 ° C. and 101.325 kPa is preferably 20% or less, preferably 10% or less, particularly preferably 5% or less, or even 1% or less, based on the total mass of component (iii).
  • Phenolic resin components (i) for binder systems in particular for use in a process from the group consisting of the polyurethane cold box process and the polyurethane no-bake process, are known in the prior art.
  • Phenolic resins a) are condensation products of one or more phenolic monomers of the general formula (II)
  • R'CHO a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.
  • R ' is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.
  • A, B and C are independently selected from the group consisting of hydrogen, unsaturated aliphatic groups with a maximum of 16 carbon atoms and saturated aliphatic groups with a maximum of 16 carbon atoms.
  • the aliphatic groups are preferably alkyl groups, preferably from the group consisting of methyl, ethyl, n-propyl, / -propyl, n-butyl, / -butyl, fe / f-butyl, octyl and nonyl, or alkenyl groups from the group consisting of pentadecenyl, pentadecadienyl and pentadecatrienyl.
  • Phenol monomers of the formula (II) in which at least one of the substituents A, B and C, preferably two of the substituents A, B and C or all of the substituents A, B and C are hydrogen, are preferred.
  • Phenol monomers suitable for the production of phenolic resins are, for example, phenol (hydroxybenzene C6H5OH), alkylphenols such as o-cresol, m-cresol, p-cresol, p-butylphenol, p- Octylphenol, p-nonylphenol, and cardanol (designation for compounds of the formula (II), where A and C are hydrogen and B is an aliphatic, unbranched alkyl or alkenyl group with 15 carbon atoms and 0, 1, 2 or 3 double bonds is).
  • phenol hydroxybenzene C6H5OH
  • alkylphenols such as o-cresol, m-cresol, p-cresol, p-butylphenol, p- Octylphenol, p-nonylphenol, and cardanol (designation for compounds of the formula (II), where A and C are hydrogen and B is an aliphatic, unbranched alkyl or alkenyl group
  • Phenol (hydroxybenzene C6H5OH), o-cresol, cardanol and their mixtures are preferred phenolic monomers for the production of phenolic resins.
  • Formaldehyde which can also be used in the form of paraformaldehyde, is preferred as the aldehyde for the production of phenolic resins.
  • Formaldehyde is used either as the sole aldehyde or in combination with one or more other aldehydes.
  • the phenolic resin component (i) of the binder system according to the invention preferably contains a phenolic resin a) in the form of an ortho-condensed resole.
  • “Ortho-condensed resole” denotes a phenolic resin, its molecules
  • terminal methylol groups arranged in the ortho position, it being possible for the terminal methylol groups to be etherified.
  • ortho or “ortho” ‘denotes the ortho position or the ortho 'position in relation to the hydroxyl group of the phenol. It is not excluded that in the molecules of the ortho-condensed resols to be used preferably according to the invention there are also aromatic rings linked by methylene groups (in addition to the aromatic rings linked by methylene ether bridges). Likewise, it is not excluded that in the molecules of the ortho-condensed resols to be preferably used according to the invention, terminal hydrogen atoms or terminal methyl groups (when using o-cresol as an additional starting material, see below) in the ortho position (in addition to terminal methylol groups in ortho Position).
  • the ratio of methylene ether bridges to methylene bridges in the molecules of the ortho-condensed resols to be preferably used according to the invention is 1: 1 or greater, and the ratio of terminal (terminal) methylol groups in the ortho position to terminal hydrogen atoms or terminal ones Methyl groups in the ortho position also 1: 1 or larger.
  • Such phenolic resins are also referred to as benzyl ether resins.
  • the structure of such ortho-condensed resol is represented by the general formula (III):
  • X selected from the group consisting of hydrogen, the methyl group CF, the methylol group CH2OH and etherified methylol groups, where preferably at least one of the groups X is a methylol group CH2OH or an etherified methylol group
  • R is hydrogen or a substituent in the meta or para position to the phenolic hydroxyl group, preferably from the group consisting of methyl, n-butyl, i-butyl, tert-butyl, octyl, nonyl, pentadecenyl, pentadecadienyl and pentadecatrienyl, m 1 or an integer> 1, preferably an integer from 1 to 10, n is for each of the m + 1 groups (purple)
  • ortho-condensed resole or “ortho-condensed phenolic resole” (English: ortho-condensed phenolic resole) includes, according to the usual professional understanding, compounds as they are in the textbook “Phenolic Resins: A Century of Progress” (editor : L. Pilato, Verlag: Springer, year of publication: 2010) are disclosed in particular on page 477 by FIG. 18.22.
  • the term also includes the “benzyl ether resins (ortho-phenol-resoles)” specified in the VDG data sheet R 305 “Urethane Cold Box Process” (February 1998) under 3.1.1.
  • the term also includes the “phenolic resins of the benzyl ether resin type” disclosed in EP 1 057 554 B1, cf.
  • Ortho-condensed resols are obtainable by polycondensation of phenol monomers with hydrogen in the ortho position and in the ortho 'position with respect to the hydroxyl group with a molar excess of formaldehyde .
  • o-cresol can be used as a further phenol monomer.
  • Formaldehyde and phenol monomers are preferably reacted in a molar ratio of greater than 1: 1 to 2: 1, preferably 1.2: 1 to 1.5: 1, in the liquid phase, typically catalyzed at a temperature below 130.degree by divalent metal ions (preferably Zn 2+ ) in a weakly acidic medium.
  • divalent metal ions preferably Zn 2+
  • the production of ortho-condensed resoles or benzyl ether resins is known in the prior art, cf. inter alia EP 1 057 554 B1.
  • the phenolic resin a) is preferably an ortho-condensed resole
  • - is a linear or branched alkyl radical with 1 to 12 carbon atoms, or an aralkyl radical with 7 to 9 carbon atoms or a furfuryl radical, or a group with a structure according to formula (IV)
  • n is an integer from 0 to 20, preferably from 0 to 4
  • each R is selected independently of the other R from the group consisting of hydroxyl groups, alkoxy groups with one to 6 carbon atoms (preferably ethoxy, propoxy or butoxy groups) and groups with a resol structure according to formula (II Ib)
  • X is hydrogen or a methyl group or a methylol group CH2OH
  • R is hydrogen or a substituent in the meta or para position to the phenolic hydroxyl group, preferably from the Group consisting of methyl, n-butyl, i-butyl, tert-butyl, octyl, nonyl, pentadecenyl, pentadecadienyl and pentadecatrienyl, m is 1 or an integer> 1, preferably an integer from 1 to 10
  • n is for each of the m + 1 groups (purple)
  • Z is a linear or branched alkyl radical with 1 to 12 carbon atoms, ie the -CH2OZ groups are alkoxymethylene groups.
  • Alkyl radicals with 1 to 9 carbon atoms are preferred here, preferably from the group consisting of methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, tert-butyl and ethylhexyl.
  • Such resins can be produced by reacting the hydroxyl groups of the unetherified terminal methylol groups -CH2OH of an orthocondensed resole with primary, secondary or tertiary alkanols, e.g. methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol- , tert-butanol and ethylhexyl alcohol.
  • Z is a linear or branched aralkyl radical (alkyl radical substituted by aryl groups) having 5 to 9 carbon atoms, or a furfuryl radical.
  • Preferred radicals R here are benzyl and furfuryl.
  • Such resins can be prepared by reacting the hydroxyl groups of unetherified terminal methylol groups -CH2OH of an ortho-condensed resole with furfuryl alcohol or an aralkyl alcohol, eg benzyl alcohol.
  • the radical Z of the etherified terminal methyl group of the ortho-condensed resol has a structure according to formula (IV) as described above.
  • n 0 in formula (IV)
  • one of the radicals R has a resol structure according to formula (IIIb) and the other radicals are ethoxy groups, or all radicals R in formula (IV) are ethoxy groups.
  • Resoles of this kind can be prepared by reacting the unetherified hydroxyl groups (i.e. the hydroxyl groups of the unetherified terminal methylol groups -CH2OH) of an ortho-condensed resol with esters of orthosilicic acid.
  • the unetherified hydroxyl groups i.e. the hydroxyl groups of the unetherified terminal methylol groups -CH2OH
  • the ratio of terminal methylol groups CH2OH to etherified terminal methylol groups CH2OZ is preferably greater than 1, preferably greater than 2, more preferably greater than 4 and particularly preferably greater than 10. It goes without saying that this is The ratio does not refer to the terminal methylol groups of an individual resol molecule, but to the totality of the terminal (etherified and unetherified) methylol groups of all resol molecules in the phenolic resin component (i).
  • Resole a is a mixture of resol molecules with two etherified terminal methylol groups, resol molecules with one etherified terminal methylol group, resol molecules with one unetherified terminal methylol group and resol molecules with two unetherified terminal methylol groups, according to the desired ratio.
  • solvent b) encompasses both individual compounds acting as solvents and mixtures of different compounds acting as solvents.
  • the solvent b) is a liquid in which component a) and, if applicable, other components of the phenolic resin component (i), insofar as they are solids, are dissolved or with component a) and possibly other components of the phenolic resin component ( i) as long as they are liquids, they are miscible so that the phenolic resin component consists of a single liquid phase.
  • the solvent b) serves in particular to adjust the viscosity of the phenolic resin component (i) in such a way that mixing with a basic molding material is facilitated.
  • the solvent b) of the phenolic resin component (i) is preferably selected from the group consisting of
  • Dialkyl esters of C 4 -C 6 dicarboxylic acids preferably from the group consisting of dimethyl adipate, dimethyl glutarate, and dimethyl succinate,
  • Saturated and unsaturated fatty acid alkyl esters preferably vegetable oil alkyl esters, preferably from the group consisting of rapeseed oil methyl ester, tall oil methyl ester, tall oil butyl ester, lauric acid methyl ester, isopropyl laurate, isopropyl myristate, and isobutyl myristic ester,
  • Alkylene carbonates preferably propylene carbonate
  • Hydrocarbons liquid at 25 ° C and 101.325 kPa preferably from the group consisting of cycloalkanes, alkanes with 6 to 22 carbon atoms and aromatic hydrocarbons, the aromatic hydrocarbons preferably being selected from the group consisting of alkylbenzenes, alkenylbenzenes, dialkyl naphthalenes, Dialkenyl naphthalenes,
  • n is an integer from 0 to 20
  • each R is selected independently of the other R from the group consisting of alkyl groups having one to 6 carbon atoms and alkoxy groups having one to 6 carbon atoms
  • Compounds of the formula (I) in which n> 0 and all R groups are alkyl groups are alkylsiloxanes.
  • Compounds of the formula (I) in which n> 0 and all R groups are alkoxy groups are alkoxysiloxanes.
  • Compounds of the formula (I) in which n> 0 and one or more groups R are alkyl groups and the remaining groups R are alkoxy groups are alkyl / alkoxy-siloxanes.
  • Tetraethylorthosilicate (TEOS) and ethoxysiloxanes, in which n is an integer from 2 to 5, are particularly preferred.
  • hydrocarbons according to its usual meaning in the field of chemistry, denotes organic compounds that consist only of carbon and hydrogen.
  • the phenolic resin is selected from the group of ortho-condensed resols as described above, and
  • the solvent is selected from the group of preferred solvents as described above.
  • the phenolic resin component (i) contains
  • - Per molecule at least one aromatic ring of 6 carbon atoms, a hydroxyl group being bonded to one of the carbon atoms of the aromatic ring and to at least one of the carbon atoms of the aromatic ring, a hydrocarbon radical is bonded, the hydrocarbon radical 1 containing 1 to 26 carbon atoms and 0 to 4 double bonds,
  • aromatic hydrocarbons being preferably selected from the group consisting of alkylbenzenes, alkenylbenzenes, dialkyl naphthalenes, dialkenyl naphthalenes, - alkylsilanes, alkyl / alkoxy silanes, alkoxysilanes, Alkylsiloxanes, alkyl / alkoxy-siloxanes and alkoxysiloxanes of the formula (I)
  • n is an integer from 0 to 20
  • each R is independently selected from the group consisting of alkyl groups having one to 6 carbon atoms and alkoxy groups having one to 6 carbon atoms
  • the phenolic resin component (i) of the binder system according to the invention optionally contains further constituents.
  • the phenolic resin component (i) of the binder system according to the invention preferably contains the lowest possible concentration
  • molecular formaldehyde (often also referred to as "free formaldehyde”) is formaldehyde that is not bound in the phenolic resin a) but is in molecular form.
  • free formaldehyde formaldehyde
  • molecular formaldehyde encompasses both monomeric formaldehyde and oligomers and polymeric forms such as paraformaldehyde (mixture of short-chain, linear poly (oxymethylene) s from 2 or more monomer units) and 1,3,5-trioxane.
  • Molecular formaldehyde contained in the phenolic resin component (i), which is introduced into the molding material mixture during the production of a molding material mixture, is - as mentioned above - an essential source for the emission of formaldehyde to be reduced according to the invention.
  • the concentration of molecular formaldehyde g) is less than 0.1%, more preferably less than 0.08%, particularly preferably less than 0.05%, the concentration in each case being based on the total mass of Phe - Molharz component (i) is based.
  • the concentration of the molecularly present formaldehyde g) in the phenolic resin component (i) can be determined, for example, using the KCN method.
  • the excess of potassium cyanide is then back-titrated with mercury (II) nitrate solution and diphenyl carbazone as an indicator.
  • the KCN method is preferably carried out in accordance with the detailed description below. The following solutions are required:
  • a blank value must be determined before each measurement.
  • 100 ml "IPA / water” are placed in a 400 ml beaker. It is mixed with a magnetic stirrer and first 40 ml of borate buffer solution, then 20 ml of KCN solution are added. After two minutes, 5 ml of phosphate buffer solution and 3 to 5 drops of indicator solution are added so that the color of the solution is observed. It is titrated with a 0.05 molar, aqueous Hg (NC> 3) 2 solution. The end point of the titration can be recognized by the color change to violet. The color should be stable for at least 10 seconds after reaching the end point. The consumption of 0.05 M Hg (NC> 3) 2 solution is noted as the “blank value”.
  • sample weight is set according to the expected formaldehyde content and is preferably selected so that approx. 10 to 20 ml of 0.05 molar Hg (NC> 3) are used for the titration. 2 solution are needed.
  • NC> 3 0.05 molar Hg
  • the sample is weighed into a 400 ml beaker with the aid of an analytical balance and dissolved in 100 ml "IPA / water". It is mixed with a magnetic stirrer and first 40 ml of borate buffer solution, then 20 ml of KCN solution are added. The pH of the solution should be around 9.3. At the end of a two-minute reaction time (measured from the moment the KCN solution is added), 5 ml of phosphate buffer solution and 3 to 5 drops of indicator solution are added so that a coloration of the solution is observed. It is titrated with a 0.05 molar, aqueous Hg (N03) 2 solution. The end point of the titration can be recognized by the color change to violet. The color should be stable for at least 10 seconds after reaching the end point. The consumption of 0.05 M Hg (N03) 2 solution is noted as the “consumption value”.
  • the concentration of molecular formaldehyde g) in the phenolic resin component (i) can be determined with a similar accuracy by means of HPLC, the determination by means of HPLC is generally preferred.
  • phenolic monomers are reacted with a relatively high molar excess of formaldehyde as described above, so that in addition to the resol a) obtained as product, high residual amounts of molecular Formaldehyde g) are present.
  • one or more ⁇ -dicarbonyl compounds which react with the molecular formaldehyde g) are added to the phenolic resin component (i) of the binder system according to the invention.
  • Reaction with ß-dicarbonyl compounds h) binds molecular formaldehyde to non-volatile reaction products in the phenolic resin component (i), so that the concentration of molecular formaldehyde in the phenolic resin component (i) is reduced.
  • the phenolic resin component (i) of a binder system according to the invention thus contains in certain cases
  • ß-dicarbonyl compounds are able to bind molecular formaldehyde with the formation of non-volatile reaction products, so they act as formaldehyde scavengers. This effect of ß-dicarbonyl compounds is i.a. in the patent application WO 2016/165916 A1.
  • the concentration of molecular formaldehyde g) in the phenolic resin component (i) of the binder system according to the invention can be reduced.
  • the use of a phenolic resin component (i) with a low concentration of molecular formaldehyde g) ensures that as little molecular formaldehyde g) as possible is introduced into a molding material mixture containing the binder system according to the invention and molded articles produced therefrom. This helps to reduce the emission of formaldehyde when processing the molding material mixture and when using moldings made from it.
  • one or more ⁇ -dicarbonyl compounds are therefore preferably added in a molar excess relative to the total amount of molecular formaldehyde g) in the production of the phenolic resin component (i).
  • phenolic resin component (i) of a binder system according to the invention thus contains in certain cases
  • Typical reaction products of dialkyl malonates with formaldehyde are, for example, 2-methylene malonic esters, 2,2-bis (hydroxymethyl) malonic esters, 2- (hydroxymethyl) malonic esters and 2- (3-hydroxy-2-oxapropyl) malonic esters.
  • dialkyl esters of malonic acid dialkyl malonates
  • Typical reaction products of dialkyl malonates with formaldehyde are, for example, 2-methylene malonic esters, 2,2-bis (hydroxymethyl) malonic esters, 2- (hydroxymethyl
  • the phenolic resin component (i) of the binder system according to the invention contains only a low concentration of molecular formaldehyde g), it is unavoidable that moldings produced with a binder system comprising this phenolic resin component (i) will not be avoided release formaldehyde over time, in particular due to the inevitable (at least partial) decomposition of the binder (polyurethane formed from the phenolic resin of the phenolic resin component (i) and the polyisocyanate of the polyisocyanate component (ii)) when exposed to heat.
  • component (iii) of the binder system according to the invention selected from the group consisting of amino acids and urea, so that the emission of formaldehyde is reduced.
  • the phenolic resin component (i) of the binder system according to the invention preferably contains the lowest possible concentration
  • Monomeric compounds from the group of phenols are phenolic monomers which are not bound in the phenolic resin a) but are in monomeric form. If the phenolic resin component (i) contains monomeric compounds i) from the group of phenols, these are mostly unconverted residual amounts of phenol monomers in the phenolic resin production. Therefore, the monomeric compounds i) from the group of phenols which may be contained in a phenolic resin component (i) are usually identical to those phenolic monomers which are in the phenolic resin a) this phenolic resin component (i) by methylene bridges or methylene ether Bridges are connected.
  • the concentration of monomeric compounds from the group of phenols i) is preferably 10% or less, preferably 5% or less, particularly preferably 1% or less, the concentration in each case being based on the total mass of the phenolic resin component (i) . If the phenolic resin component (i) of the binder system according to the invention contains a resol as phenolic resin a), then the phenolic resin component (i) usually also contains j) one or more compounds from the group of hydroxybenzyl alcohols.
  • hydroxybenzyl alcohols j are in particular saligenin (2-hydroxybenzyl alcohol, o-hydroxybenzyl alcohol) and homosaligenin (4-hydroxybenzyl alcohol, p-hydroxybenzyl alcohol). These are created in the manufacture of phenolic resins by adding a molecule of formaldehyde to a molecule of phenol (hydroxybenzenes). For details, reference is made to DE 10 2016 125 700 A1.
  • the concentration of compounds from the group of hydroxybenzyl alcohols j) in the phenolic resin component (i) of the binder system according to the invention is preferably higher than the concentration of monomeric phenol (monomeric hydroxybenzene).
  • the mass ratio of compounds j) from the group of hydroxybenzyl alcohols to monomeric phenol (hydroxybenzene) is preferably greater than or equal to 1.2, preferably 1.2 to 30, and / or the mass ratio of saligenin to phenol (hydroxybenzene) is greater than or equal to 1 , 1 preferably 1, 1 to 25, the concentration of monomeric phenol in each case preferably being less than 2.5%, preferably less than 2%, the concentrations being based in each case on the total mass of the phenolic resin component (i).
  • the phenolic resin component contains (i) of the binder system according to the invention
  • the phenolic resin component contains (i) of the binder system according to the invention
  • Hydrofluoric acid improves the moisture resistance of foundry molds and foundry cores, especially when hydrofluoric acid is used together with silanes I).
  • binder systems are preferred, the phenolic resin component (i)
  • the invention is not restricted to binder systems whose phenolic resin component (i) contains constituent h) as defined above.
  • Polyisocyanate components (ii) for binder systems in particular for use in a process from the group consisting of the polyurethane cold box process and the polyurethane no-bake process, are known in the prior art
  • Isocyanates c) with two or more isocyanate groups per molecule are generally referred to as polyisocyanates. Isocyanates with exactly two isocyanate groups per molecule are specifically referred to as diisocyanates.
  • the isocyanates c) with at least two isocyanate groups per molecule are preferably selected from the group consisting of
  • MDI Methylenebis (phenyl isocyanates)
  • diphenylmethane diisocyanates preferably 4,4’-methylenebis (phenyl isocyanate)
  • Polymethylene polyphenyl isocyanates also known as “polymeric MDI”
  • aliphatic isocyanates aliphatic isocyanates
  • Isocyanates with at least two isocyanate groups and one urethoneimine group per molecule also referred to as urethoneimine-modified di- or polyisocyanates, preferably urethoneimine-modified MDI.
  • polymeric MDI also includes mixtures of different polymethylene-polyphenyl-isocyanates.
  • Mixtures of different isocyanates c) with at least two isocyanate groups per molecule can be used, e.g.
  • the polyisocyanate contains component
  • solvent d) includes both individual compounds acting as solvents and mixtures of different compounds acting as solvents.
  • the solvent d) is a liquid in which the constituents c) and possibly further constituents of the polyisocyanate component (ii), insofar as they are solids, are dissolved or with which the constituents c) and possibly further constituents of the polyisocyanate Component (ii), insofar as they are liquids, are miscible, so that the polyisocyanate component (ii) consists of a single liquid phase.
  • the solvent d) serves in particular to set the viscosity of the polyisocyanate component (ii) so that mixing with a basic molding material is facilitated.
  • the solvent d) is preferably selected from the group consisting of
  • Dialkyl esters of C 4 -C 6 dicarboxylic acids preferably from the group consisting of dimethyl adipate, dimethyl glutarate, and dimethyl succinate,
  • Saturated and unsaturated fatty acid alkyl esters preferably vegetable oil alkyl esters, preferably from the group consisting of rapeseed oil methyl ester, tall oil methyl ester, tall oil butyl ester, lauric acid methyl ester, isopropyl laurate, isopropyl myristate, and isobutyl myristic ester,
  • Alkylene carbonates preferably propylene carbonate
  • Hydrocarbons liquid at 25 ° C and 101.325 kPa preferably from the group consisting of cycloalkanes, alkanes with 6 to 22 carbon atoms and aromatic hydrocarbons, the aromatic hydrocarbons preferably being selected from the group consisting of alkylbenzenes, alkenylbenzenes, dialkyl naphthalenes and Dialkenyl naphthalenes,
  • n is an integer from 0 to 20
  • each R is selected independently of the other R from the group consisting of alkyl groups having one to 6 carbon atoms and alkoxy groups having one to 6 carbon atoms
  • Compounds of the formula (I) in which n> 0 and all R groups are alkyl groups are alkylsiloxanes.
  • Compounds of the formula (I) in which n> 0 and all groups R are alkoxy groups are alkoxylsiloxanes.
  • Compounds of the formula (I) in which n> 0 and one or more groups R are alkyl groups and the remaining groups R are alkoxy groups are alkyl / alkoxy-siloxanes.
  • Tetraethylorthosilicate (TEOS) and ethoxysiloxanes, in which n is an integer from 2 to 5, are particularly preferred.
  • hydrocarbons according to its usual meaning in the field of chemistry, denotes organic compounds that consist only of carbon and hydrogen.
  • Binder systems according to the invention are particularly preferred, where in the polyisocyanate component (ii)
  • one or more (preferably all) isocyanates with at least two isocyanate groups per molecule are selected from the group of preferred isocyanates as described above, and
  • the solvent is selected from the group of preferred solvents as described above.
  • binder systems where in the polyisocyanate component (ii) c) one or more isocyanates from the group consisting of MDI, polymeric MDI, carbodiimide-modified MDI and urethonimine-modified MDI and mixtures thereof, the total concentration of said isocyanates c ) Is 75% to 95%, and
  • alkoxysilanes alkyl silicates
  • alkoxysiloxanes alkyl silicate oligomers
  • alkylene carbonates preferably propylene carbonate
  • fatty acid alkyl esters preferably from the group consisting of rapeseed oil methyl ester and tall oil methyl ester
  • ß-dicarbonyl compounds are able to bind molecular formaldehyde through reactions with the formation of non-volatile reaction products. Since the polyisocyanate component (ii) of the binder system according to the invention does not contain any formaldehyde, the aforementioned reaction of the ⁇ -dicarbonyl compounds m) with formaldehyde only takes place when the ß- contained in the polyisocyanate component (ii) of the binder system according to the invention Dicarbonyl compounds m) come into contact with molecular formaldehyde.
  • the ß-dicarbonyl compounds m) contained in the polyisocyanate component (ii) of a binder system according to the invention are preferably selected from the group of dialkyl esters of malonic acid (dialkyl malonates), the alkyl groups being independently selected from alkyl groups having 1 to 4 carbon atoms.
  • Diethyl malonate (diethyl malonate) and dimethyl malonate (dimethyl malonate) are particularly preferred.
  • Typical reaction products of dialkyl malonates with formaldehyde are, for example, 2-methylenemalonic ester, 2,2-bis (hydroxymethyl) malonic ester, 2- (hydroxymethyl) malonic ester and 2- (3-hydroxy-2-oxapropyl) malonic ester.
  • a binder system for the production of moldings the phenolic resin component (i) of which has a very low concentration of molecular formaldehyde g) (as described above), and the binder system without heat supply by a process from the group consisting of the polyurethane cold box process and the polyurethane no bake process (to)
  • moldings produced in this way also tend to release formaldehyde over time, in particular when exposed to heat.
  • This is converted into non-volatile compounds by reaction with substances e) contained in component (iii) of the binder system according to the invention selected from the group consisting of amino acids and urea as well as ß-dicarbonyl compounds m) contained in polyisocyanate component (ii) Bound reaction products, so that the emission of formaldehyde is reduced.
  • the polyisocyanate component (ii) contains further constituents n). In some cases it is preferred for the polyisocyanate component (ii) n) to contain one or more substances from the group consisting of
  • Acid chlorides e.g. Phosphoryl chloride, phthaloyl chloride,
  • esters of one or more phosphorus-oxygen acids the total amount of esters (bv) being in the range from 5.0% to 90.0%
  • silanes selected from the group consisting of aminosilanes, epoxysilanes, mercaptosilanes and ureidosilanes, the total amount of the silanes (cv) being in the range from 5.0% to 90.0%, with the maximum proportion of water Is 0.1%
  • the above Components n) essentially serve to extend the period of time by inhibiting the formation of polyurethane, during which a molding material mixture, in which both components of the binder system are mixed, can be stored despite the high reactivity of the binder system (“sand life time”) without becoming unusable , ie to be no longer malleable. Long sand lifetimes are desirable so that a prepared batch of molding material mixture does not become unusable due to premature hardening of the binding agent system.
  • the above Additives are also referred to as bench life extenders and are known to those skilled in the art.
  • acid chlorides from the group consisting of phosphoryl chloride POCI3 (CAS No.
  • o-phthaloyl chloride (1,2-benzenedicarbonyl chloride, CAS No. 88-95-9) and benzene-phosphorus oxydichloride ( CAS no: 842-72-6) is used.
  • Further suitable additives are methanesulfonic acid and phosphorus oxyacids, preferably from the group consisting of phosphinic acid, phosphonic acid, phosphoric acid, peroxophosphoric acid, hypodiphosphonic acid, diphosphonic acid, hypodiphosphoric acid, diphosphoric acid and peroxodiphosphoric acid.
  • a preferred additive which extends the sand service life is an additive mixture which can be produced by reacting a premix of the above-mentioned components (av), (bv) and (cv), as described in patent application WO 2013/117256.
  • the polyisocyanate component (ii) contains one or more further constituents n) from the group of plasticizers.
  • the total concentration of all substances n) is 5% or less, preferably 3% or less.
  • one or both of components (i) and (ii) furthermore comprise o) one or more silicone surfactants comprising per molecule at least one structural unit -Si (C n H 2 n + i) 2 -0-, where n is an integer from 1 to 3, and at least one polyalkoxy group
  • concentration of the silicone surfactants o) is preferably 0.001% to 1.0%, preferably from 0.001% to 0.8% and particularly preferably from 0.002% to 0.5%, based on the sum of the mass of the component (i ) and the mass of component (ii).
  • concentration of the silicone surfactants o is preferably 0.001% to 1.0%, preferably from 0.001% to 0.8% and particularly preferably from 0.002% to 0.5%, based on the sum of the mass of the component (i ) and the mass of component (ii).
  • the concentration of the silicone surfactants o) is preferably 0.001% to 1, 0%, more preferably 0.001% to 8% and particularly preferably from 0.002% to 0.5%, based on the sum of the masses of component (i) and component (ii).
  • a binder system according to the invention, the person skilled in the art will select the amount of component (iii) and thus of the substances e) contained therein selected from the group consisting of amino acids and urea so that it is sufficient to ensure the highest possible proportion of the phenolic resin component ( i) molecular formaldehyde contained in the binder system g) and the formaldehyde released during processing of a molding material mixture produced with the binder system according to the invention and during further processing (especially under thermal stress), storage and use of molded articles produced therefrom by the formation of non-volatile reaction products.
  • the person skilled in the art takes into account that the amount of component (iii) to be used and thus of the substances e) contained therein must be selected so that the reactivity between the binder components (i) and (ii) is not impaired, the sand lifetime (see above) is not unacceptably shortened, and the strength of molded bodies produced from a molding material mixture containing the binder system according to the invention is not impaired.
  • the amount of component (iii) to be used and thus of the substances e) contained therein is based on the amount of phenolic resin component (i) to be used to produce the molding material mixture, optionally the presence of further formaldehyde scavengers in the binder system (e.g.
  • the binder system according to the invention does not contain any further formaldehyde scavengers in addition to substances e) selected from the group consisting of amino acids and urea in component (iii), then the molar ratio of substances e) to the total amount of available formaldehyde is preferably 4: 1 to 1 :1. If the binder system according to the invention contains further formaldehyde scavengers in addition to substances e) selected from the group consisting of amino acids and urea in component (iii), the molar ratio of the total of all formaldehyde scavengers to the total amount of available formaldehyde is preferably 4: 1 to 1: 1.
  • Available formaldehyde is understood to mean the total amount of the molecular formaldehyde g) contained in the phenolic resin component (i) of the binder system and of the formaldehyde that can be released during the decomposition of the binder, cf. the above explanation of the two sources of formaldehyde emissions.
  • a second aspect of the present invention relates to a molding material mixture comprising a molding base material and components (i), (ii) and (iii) of a binder system according to the first aspect of the present invention.
  • the molding material mixture according to the second aspect of the present invention comprises components (i), (ii) and (iii) of a binder system according to the first aspect of the present invention described above
  • the total concentration of components (i) and (ii) of the binder system according to the first aspect of the present invention described above is usually 0.6% to 14%, based on the total mass of the molding material mixture.
  • the total concentration of components (i) and (ii) of the binder system according to the first aspect of the present invention described above is usually 0.6% up to 3%, preferably 0.8% to 2%, particularly preferably 1.0% to 1.6%, based on the total mass of the molding material mixture.
  • the total concentration of components (i) and (ii) of the binder system according to the first aspect of the present invention described above is usually 8% to 14%, preferably 10% to 12%, based on the total mass the molding material mixture.
  • the stoichiometric ratio of isocyanate groups in the polyisocyanate component (ii) to hydroxyl groups in the phenolic resin component (i) is preferably in the range from 0.5 to 1.5, more preferably in the range - Rich from 0.6 to 1.4, more preferably in the range from 0.7 to 1.3, particularly preferably in the range from 0.8 to 1.2, very particularly preferably in the range from 0.9 to 1.1 , especially preferably in the range from 0.95 to 1.05.
  • basic molding material comprises both individual materials suitable as basic molding material and mixtures of different materials suitable as basic molding material. All basic mold materials commonly used for the production of feeders, foundry molds and foundry cores are suitable as basic mold materials, e.g. Quartz sand and special sands.
  • special sand encompasses natural mineral sands as well as sintered and melted products that are produced in granular form or converted into granular form by crushing, grinding and classifying processes, or inorganic mineral sands produced by other physical-chemical processes that are used as basic molding materials with foundries Binders are used for the manufacture of risers, cores and molds. Special sands include, among others
  • the basic mold material preferably contains a proportion of recycled foundry sand.
  • a feeder compound according to the invention comprises typically insulating fillers such as hollow microspheres, optionally fiber material, and in the case of exothermic feeders, an oxidizable metal and an oxidizing agent for the oxidizable metal.
  • insulating fillers such as hollow microspheres, optionally fiber material, and in the case of exothermic feeders, an oxidizable metal and an oxidizing agent for the oxidizable metal.
  • the molding material mixture (in addition to the above-mentioned components) comprises one or more reaction products of formaldehyde with one or more substances e) selected from the group consisting of amino acids and urea.
  • the molding material mixture according to the invention is selected from among those selected by reacting substances e) Group consisting of amino acids and urea with molecular formaldehyde g) reaction products formed from the phenolic resin component (i) also contains unreacted substances e) selected from the group consisting of amino acids and urea.
  • the concentration of the concentration of substances e) introduced into the molding material mixture with component (iii) selected from the group consisting of amino acids and urea is set so that there is a molar excess relative to that with phenolic resin component (i) amount of molecular formaldehyde g) introduced into the molding material mixture.
  • component (iii) selected from the group consisting of amino acids and urea) the above statements regarding the first aspect of the present invention apply.
  • the total amount of unreacted substances e) in the molding material mixture according to the invention is preferably selected from the group consisting of amino acids and urea
  • substances bound in reaction products with formaldehyde e) selected from the group consisting of amino acids and urea
  • 0.1% to 5.0% preferably 0.1% to 3.5%, particularly preferably 0.1% to 2.0%, and very particularly preferably 0.5% to 2.0%, based on the Total mass of the molding material mixture.
  • the total amount is
  • a third aspect of the present invention relates to a method comprising the steps:
  • the molded body formed by hardening the binder system in the molded molding material mixture can be subjected to further processing with the supply of heat.
  • the inventive method can be a further Processing step include a thermal treatment of the molded body formed by curing the binder system in the molded molding material mixture.
  • components (i) and (ii) of the binder system according to the invention are preferably dosed in such a way that the total concentration of components (i) and (ii) of the binder system is 0.6% to 14% based on the total mass of the molding mixture.
  • components (i) and (ii) of the binder system according to the invention are preferably dosed in such a way that the stoichiometric ratio of isocyanate groups of isocyanates c) to hydroxyl groups of phenolic resins a) is in the range from 0.5 to 1, 5 lies.
  • the person skilled in the art will dose the amount of component (iii) to be used and thus of the substances e) contained therein selected from the group consisting of amino acids and urea so that it is sufficient to contain as high a proportion as possible of the phenolic resin component (i) molecular formaldehyde contained in the binder system g) and the formaldehyde released during processing of the molding material mixture and during further processing (especially under thermal stress), storage and use of molded articles produced therefrom by the formation of non-volatile reaction products.
  • component (iii) to be used and thus of the substances e) contained therein selected from the group consisting of amino acids and urea so that it is sufficient to contain as high a proportion as possible of the phenolic resin component (i) molecular formaldehyde contained in the binder system g) and the formaldehyde released during processing of the molding material mixture and during further processing (especially under thermal stress), storage and use of molded articles produced therefrom by the formation of non-volatile reaction products
  • the person skilled in the art takes into account that the amount of component (iii) to be used and thus of the substances e) contained therein must be selected so that the reactivity between the binder components (i) and (ii) is not impaired, the sand lifetime (see above) is not unacceptably shortened, and the strength of molded bodies produced from a molding material mixture containing the binder system according to the invention is not impaired.
  • the amount of component (iii) to be used and thus of the substances e) contained therein is thus based on the amount of phenolic resin component (i) to be used to produce the molding material mixture, optionally the presence of further formaldehyde scavengers in the binder system (e.g. the abovementioned ß-dicarbonyl compounds ) or the possibility of providing the molded body produced with a coating containing formaldehyde scavengers (further details are described below), as well as the requirements of the reactivity of the binder system and the strength of a molding material mixture produced containing the binder system according to the invention.
  • further formaldehyde scavengers in the binder system e.g. the abovementioned ß-dicarbonyl compounds
  • further formaldehyde scavengers in the binder system
  • the possibility of providing the molded body produced with a coating containing formaldehyde scavengers further
  • the binder system according to the invention does not contain any further formaldehyde scavengers in addition to substances e) selected from the group consisting of amino acids and urea in component (iii), then the molar ratio of substances e) to the total amount of available formaldehyde is preferably 4: 1 to 1 :1 . If the binder system according to the invention contains further formaldehyde scavengers in addition to substances e) selected from the group consisting of amino acids and urea in component (iii), the molar ratio of the total of all formaldehyde scavengers to the total amount of available formaldehyde is preferably 4: 1 to 1: 1 .
  • component (iii) of the binder system according to the invention is particularly preferably dosed in such a way that the total amount of substances e) selected from the group consisting of amino acids and urea 0.1% to 5.0%, preferably 0.1% to 3.5%, particularly preferably 0.1% to 2.0%, and very particularly preferably 0.5% to 2.0%, based on the total mass of the molding material mixture.
  • component (iii) of the binder system according to the invention contains glycine as substance e)
  • component (iii) is preferably dosed to produce the molding material mixture in such a way that the amount of glycine is 0.1% to 5.0%, preferably 0.1% to 3.5%, particularly preferably 0.1% to 2.0%, and very particularly preferably 0.5% to 2.0%, based on the total mass of the molding material mixture.
  • the molding material mixture is usually shaped by filling the molding material mixture into a molding tool, blowing it or shooting it and then optionally compressing it.
  • the hardening of the binder system in the molded molding material mixture is preferably carried out without the supply of heat.
  • the molded molding material mixture is contacted to harden the binder system
  • the curing of a binder system comprising a phenolic resin component (i) and a polyisocyanate component (ii) in the presence of a gaseous tertiary amine or a mixture of two or more gaseous tertiary amines is known in the art as the polyurethane cold box process , the curing of a binder system comprising a phenolic resin component (i) and a polyisocyanate component (ii) in the presence of a liquid tertiary amine or with a mixture of two or more liquid tertiary amines as a polyurethane no-bake process.
  • the tertiary amine is preferably selected from the group consisting of triethylamine, dimethylethylamine, diethylmethylamine, dimethylisopropylamine, dimethylpropylamine and mixtures thereof.
  • the tertiary amines to be used are liquid at room temperature and are vaporized for use in the polyurethane cold box process by supplying heat, and the vaporized tertiary amine is sprayed or injected into the mold - if necessary by means of a carrier gas stream.
  • the molded body produced in the process according to the invention contains a basic molding material bound by a polyurethane which has been formed by curing a binder system according to the first aspect of the present invention.
  • the molded body produced in the process according to the invention also contains one or more substances e) selected from the group consisting of amino acids and urea and / or one or more reaction products formed by reacting these substances e) with formaldehyde.
  • the molded article produced contains e) glycine and / or one or more reaction products formed by reacting glycine with formaldehyde.
  • reaction products arise in the process according to the invention on the one hand when molecular formaldehyde g) is introduced during the production of the molding material mixture through the phenolic resin component (i), and on the other hand in particular when when the binder system in the molded molding mixture is hardened with the supply of heat (which, however, is not preferred according to the invention) as well as when the molded body formed by hardening the binder system in the molded molding mixture is subjected to further processing with supply of heat (for details see below).
  • the molded body formed by curing the binder system in addition to optionally one or more reaction products formed by reacting the substances e) selected from the group consisting of amino acids and urea with molecular formaldehyde g) from the phenolic resin component (i), also have a or contains several unreacted substances e) selected from the group consisting of amino acids and urea, which bind formaldehyde by forming non-volatile reaction products during further processing of the shaped body, so that the emission of formaldehyde from the shaped body is reduced.
  • the substances e) selected from the group consisting of amino acids and urea the above statements regarding the first aspect of the present invention apply.
  • the molding formed by curing the binder system in the molded molding material mixture is an article from the group consisting of feeders, foundry molds and foundry cores, i.e. the molded body obtained by the process according to the invention can be used as a foundry core, as a foundry mold or as a feeder without further processing steps.
  • Foundry cores, foundry molds and feeders, their design, mode of operation and use are known to the person skilled in the art.
  • a second version of the method according to the invention several moldings are formed and combined to form an article from the group consisting of foundry molds and foundry cores or combinations of a casting mold with one core or with several cores.
  • Such articles composed of several shaped bodies are e.g. referred to as core packages.
  • Such composite foundry molds and foundry cores or combinations of a foundry mold with one or more cores are required in particular for the production of castings with complex geometry.
  • the molded bodies to be connected are plugged into one another, and in special cases also glued or screwed to one another.
  • the molded body formed by hardening the binder system in the molded molding material mixture is subjected to further processing steps to form a foundry core, a foundry mold or a To form feeders, the article thus formed from the group consisting of foundry cores, foundry molds and feeders comprising the molded body formed by hardening the binder system in the molded molding material mixture.
  • the further processing step consists in providing a molded body formed by curing the binder system in the molded molding material mixture with a coating.
  • the method according to the invention comprises the steps
  • a molding material mixture by mixing a molding base material with the components (i), (ii) and (iii) of a binder system according to the invention and optionally further constituents of the molding material mixture to be produced, molding the molding material mixture, and curing the binder system in the molded molding material mixture, whereby a molding is formed ,
  • a coating composition comprising particles of one or more refractory materials dispersed in a carrier liquid to the shaped body, a coated shaped body being formed whose surface has areas provided with the coating composition,
  • Coating compositions comprising particles of one or more refractory materials dispersed in a carrier liquid are also referred to as size compositions. Such sizing compositions are known in the art and are used e.g. in the patent application WO 2011/003637 A1. The coatings formed therefrom are also referred to as size coatings or sizes.
  • refractory refers to masses, materials and minerals that can withstand at least briefly the temperature load during casting or when solidifying an iron melt, usually cast iron. Masses, materials and minerals that can withstand the casting heat of molten steel for a short time are referred to as "highly refractory". The temperatures that can occur when casting steel melts are mostly in the range higher than the temperatures that can occur when casting iron or cast iron melts. Refractory masses, materials and minerals (refractory materials) and highly refractory masses, materials and minerals are known to the person skilled in the art, for example from DIN 51060: 2000-06.
  • pulverulent refractory materials have an average grain size (preferably measured by means of light scattering according to ISO 13320: 2009-10) in the range from 0.1 ⁇ m to 500 ⁇ m, preferably in the range from 1 ⁇ m to 200 ⁇ m.
  • Particularly suitable refractory materials are those materials which have melting points which are at least 200 ° C. above the temperature of the molten metal used in each case and / or which do not react with the molten metal.
  • the term “refractory material as used here also includes highly refractory materials.
  • the refractories are selected from those refractories commonly used in sizes, e.g. Refractory materials selected from the group consisting of quartz, aluminum oxide, zirconium dioxide, aluminum silicates, non-swellable sheet silicates, zirconium silicates, olivine, talc, mica, graphite, coke, feldspar, diatomite, kaolins, calcined kaolins, metakaolinite, iron oxide and bauxite.
  • Refractory materials selected from the group consisting of quartz, aluminum oxide, zirconium dioxide, aluminum silicates, non-swellable sheet silicates, zirconium silicates, olivine, talc, mica, graphite, coke, feldspar, diatomite, kaolins, calcined kaolins, metakaolinite, iron oxide and bauxite.
  • compositions for the production of size coatings often contain further components such as wetting agents, rheological additives, binders, thickening agents and / or biocides.
  • wetting agents such as wetting agents, rheological additives, binders, adjusting agents and biocides and their function and effect are known to the person skilled in the art.
  • the carrier liquid only serves as a vehicle for applying the substances suspended and dissolved in it to the shaped body and is removed by thermal treatment of the coated shaped body.
  • the carrier liquid is liquid under normal conditions (25 ° C and 1013.25 hPa) and can be evaporated under normal pressure (1013.25 hPa) at temperatures above 40 ° C, preferably in the range from 50 ° C to 200 ° C.
  • the carrier liquid is preferably selected from the group consisting of water, methanol, ethanol and isopropanol.
  • the coating composition is usually applied to the shaped body by a method selected from the group consisting of spraying, dipping, flooding and brushing, preferably dipping.
  • a method selected from the group consisting of spraying, dipping, flooding and brushing preferably dipping.
  • the carrier liquid is removed from the applied coating composition.
  • the resulting coating which comprises particles of one or more refractory materials, forms a surface of the foundry mold or the foundry core that comes into contact with a molten metal during the casting process.
  • Molecular formaldehyde is often formed when the molded body formed by curing the binder system in the molded molding material mixture is subjected to thermal stress. If the molded body formed by curing the binder system in the molded molding material mixture is to be subjected to a further processing step in the method according to the invention, which includes a thermal treatment, e.g.
  • a further processing step in the method according to the invention which includes a thermal treatment, e.g.
  • the molded body formed by hardening the binder system in the molded molding material mixture contains one or more substances e) selected from the group consisting of amino acids and urea, which are formed during its further processing Bind formaldehyde through the formation of non-volatile reaction products, so that the emission of formaldehyde is reduced.
  • a coating composition is particularly preferably used which contains particles of one or more refractory materials dispersed in a carrier liquid and one or more compounds which are able to form non-volatile compounds by reaction with formaldehyde, so that the emission of formaldehyde in the thermal treatment to remove the carrier liquid of the coating composition is further reduced.
  • Such coating compositions, as well as their production, use and effect are described in the unpublished patent application DE 10 2018 1 18 291.0 of the applicant of the present patent application.
  • a coating composition which contains one or more formaldehyde scavengers from the group consisting of
  • Tree resins, tannins and lignins Tree resins, tannins and lignins.
  • the formaldehyde produced during the thermal treatment of the coated molding is bound by the formaldehyde scavengers contained in the applied coating composition with the formation of non-volatile reaction products, so that the coating formed from the coating composition contains one or more reaction products formed by reaction of the formaldehyde scavenger contained in the coating composition with formaldehyde.
  • a binder system according to the invention is used to produce the molding material mixture, the phenolic resin component (i) of which
  • component (iii) selected from the group consisting of amino acids and
  • a coating composition is used to produce the coating which contains one or more compounds which are capable of forming non-volatile compounds by reaction with formaldehyde.
  • a preferred second special variant of the method according to the invention comprises the steps
  • a coating composition comprising particles of one or more refractory materials dispersed in a carrier liquid to the shaped body, a coated shaped body being formed whose surface has areas provided with the coating composition,
  • Moldings made by molding the o.g. Molding material mixture or another molding material mixture and hardening of the binder system in which the molded molding material mixture has been produced, to form a composite molding, thermal treatment of the composite molding at a temperature above 40.degree. C., preferably in the range from 50.degree. C. to 200.degree , being a
  • Article from the group consisting of foundry molds and foundry cores and combinations of a casting mold with cores is obtained, the surface of which has areas in which a coating comprising one or more refractory materials is arranged.
  • several moldings are produced which are intended to be assembled to form an article from the group consisting of foundry molds and foundry cores or combinations of a casting mold with one core or with several cores. At least one of these moldings is produced by molding a molding mixture containing components (i), (ii) and (iii) of a binder system according to the above-described first aspect of the present invention and curing the binder system in the molded molding mixture.
  • a coating composition comprising particles of one or more refractory materials dispersed in a carrier liquid is applied to this shaped body, a coated shaped body being formed whose Has surface areas provided with the coating composition.
  • the same molding material mixture or another molding material mixture is used for the production of the further molded bodies.
  • This other molding material mixture can contain a binder system not according to the invention.
  • a coating composition comprising particles of one or more refractory materials dispersed in a carrier liquid can be applied to one, several or all further shaped bodies, a coated shaped body being formed, the surface of which has areas provided with the coating composition.
  • the molded bodies produced, among which there is at least one coated molded body produced from a molding material mixture with a binder system according to the invention, are then joined to form a composite molded body.
  • the carrier liquid is removed from the applied coating composition.
  • the resulting coating which comprises particles of one or more refractory materials, forms a surface of the foundry mold or the foundry core that comes into contact with a molten metal during the casting process.
  • a coating composition is preferably used as described above in the context of the first special variant of the method according to the invention, which contains particles of one or more refractory materials dispersed in a carrier liquid and one or more compounds which are capable of to form non-volatile compounds by reaction with formaldehyde, so that the emission of formaldehyde during the thermal treatment to remove the carrier liquid of the coating composition is further reduced.
  • a method according to the second special variant of the method according to the invention therefore preferably comprises the steps
  • a fourth aspect of the present invention relates to articles selected from the group consisting of foundry molds and foundry cores. Such articles can be produced by a method according to the third aspect of the present invention described above.
  • such an article comprises a molded body which
  • such an article comprises a molded body which
  • such an article comprises a shaped body which
  • a basic molding material bound by a polyurethane formed by curing a binder system according to the invention preferably a basic molding material bound by a binder system according to the first aspect of the invention as described above from the phenolic resin of the phenolic resin component (i) and the polyisocyanate of the polyisocyanate component (ii) formed hardened polyurethane,
  • the article according to the invention preferably comprises a shaped body which
  • a basic molding material bound by a polyurethane formed by curing a binder system according to the invention preferably a basic molding material bound by one of the phenolic resin, the phenolic resin component (i) and the
  • an article according to the invention comprises a molded body which
  • a base molding material bound by a polyurethane formed by curing a binder system according to the invention preferably a base molding material bound by a binder system made from the phenolic resin of the phenolic resin component (i) and the polyisocyanate of the polyisocyanate component (ii) cured polyurethane formed according to the first aspect of the invention as described above,
  • reaction products formed by reacting one or more substances e) selected from the group consisting of amino acids and urea with formaldehyde
  • the surface of the article has areas in which a coating is arranged which comprises particles of one or more refractory materials.
  • an article according to the invention comprises a molded body that binds a basic molding material by a polyurethane formed by curing a binder system according to the first aspect of the invention described above, and one or more consisting of reacting substances e) selected from the group contains reaction products formed from amino acids and urea with formaldehyde.
  • the surface of the article has areas in which a coating is arranged which comprises particles of one or more refractory materials. The coating forms a surface of the foundry mold or the foundry core which comes into contact with a molten metal during the casting process. It is not necessary for the coating to extend over the entire surface of the article. Such coatings are usually referred to as sizing.
  • Articles according to the invention of this first special embodiment can be produced by a method according to the invention according to the first special variant described above.
  • a basic molding material bound by a polyurethane formed by curing a binder system according to the invention preferably a basic molding material bound by a binder system according to the first aspect of the invention as described above from the phenolic resin of the phenolic resin component (i) and the polyisocyanate of the polyisocyanate component (ii) formed hardened polyurethane,
  • reaction products formed by reacting glycine with formaldehyde As well as one or more reaction products formed by reacting glycine with formaldehyde
  • an article according to the invention comprises several interconnected molded bodies, at least one of the interconnected molded bodies
  • a base molding material bound by a polyurethane formed by curing a binder system according to the invention preferably a base molding material bound by a binder system according to the first aspect of the invention as described above from the phenolic resin of the phenolic resin component (i) and the polyisocyanate of the polyisocyanate component (ii) formed hardened polyurethane
  • an article according to the invention comprises several molded bodies connected to one another. At least one of the interconnected molded bodies contains a basic molding material bound by a polyurethane formed by curing a binder system according to the first aspect of the invention described above, as well as one or more reaction products formed by reacting substances e) selected from the group consisting of amino acids and urea with formaldehyde .
  • all interconnected molded bodies contain a basic molding material bound by a polyurethane formed by curing a binder system according to the first aspect of the invention described above, and one or more formed by reacting substances e) selected from the group consisting of amino acids and urea with formaldehyde Reaction products.
  • the surface of the article has areas in which a coating is arranged which comprises particles of one or more refractory materials.
  • the coating forms a surface of the foundry mold or the foundry core that comes into contact with a molten metal during the casting process. It is not necessary for the coating to extend over the entire surface of the article.
  • Such coatings are usually referred to as sizing.
  • Articles according to the invention of this second special embodiment can be produced by a method according to the invention according to the second special variant described above.
  • An article according to this second special embodiment preferably comprises a plurality of shaped bodies connected to one another, at least one of the shaped bodies connected to one another
  • a base molding material bound by a polyurethane formed by curing a binder system according to the invention preferably a base molding material bound by a binder system according to the first aspect of the invention as described above from the phenolic resin of the phenolic resin component (i) and the polyisocyanate of the polyisocyanate component (ii) formed hardened polyurethane
  • reaction products formed by reacting glycine with formaldehyde As well as one or more reaction products formed by reacting glycine with formaldehyde
  • the surface of the article has areas in which a coating is arranged which comprises particles of one or more refractory materials.
  • the coating contains formaldehyde with one or more compounds selected from the group consisting of
  • the coating contains the formaldehyde scavengers contained in the coating composition with the formaldehyde formed during the thermal treatment of the coated molding.
  • binder system for the production of articles from the group consisting of foundry molds, foundry cores and feeders,
  • the molded body containing a basic molding material which is obtained by hardening a binder system according to the first aspect of Invention as described above formed polyurethane is bound, preferably a molding base bound by a cured one formed from the phenolic resin of the phenolic resin component (i) and the polyisocyanate of the polyisocyanate component (ii) of a binder system according to the first aspect of the invention as described above Polyurethane.
  • the basic mold material preferably contains a proportion of recycled foundry sand.
  • the data in% relate in each case to the total mass of the phenolic resin component (i), the polyisocyanate component (ii) or the component (iii).
  • the components are spatially separated from one another, i.e. they are in separate containers.
  • Isocyanate c) polymeric MDI, 80%
  • each of the binder systems I, II and III consists of components (i) and (ii) as indicated above, the components being spatially separated from one another, i.e. in separate containers.
  • binder system I various variants according to the invention were tested, which differed in terms of the composition of component (iii), which was each provided in a separate container.
  • concentration of the glycine relates in each case to the total mass of component (iii).
  • the solids content in component (iii) according to variant 3 being at least 80%, based on the total mass of component (iii) according to variant 3.
  • the further constituents f) of variants 3, 4a and 4b of component (iii) are customary constituents of additive mixtures for molding material mixtures. Such additives are state of the art, they serve e.g. to avoid casting defects.
  • molding material mixtures not according to the invention were produced to which, instead of component (iii), a comparative additive 3 or 4 was added, each of which contains the above contained further constituents of variant 3 or 4a and 4b of component (iii), but no substances from the group consisting of urea and amino acids.
  • the other constituents of variant 3 of component (iii) are present in the same concentration ratios relative to one another as in variant 3 of component (iii).
  • the basic molding material 100 parts by weight was placed in a mixing container.
  • the phenolic resin component (i) (0.7 parts by weight) and the polyisocyanate component (ii) (0.7 parts by weight) of the respective binder system and, if applicable, component (iii) (see the tables below for parts by weight) or a comparative additive as described above were then weighed into the mixing container so that they do not mix directly.
  • the basic molding material, phenolic resin component (i), polyisocyanate component (ii) and, if necessary, component (iii) (see table below for parts by weight) or comparative additive were mixed in a bull mixer for 120 seconds at level 4 to form a molding material mixture.
  • the molding material mixture was shaped using a Multiserw core shooter at a shooting pressure of 4 bar (400 kPa).
  • gassing was carried out for 10 seconds at a gassing pressure of 2 bar (200 kPa) using a gassing device Titronic 110 Plus with dimethylpropylamine (in a carrier gas stream) at a temperature in the range from 20 to 30 ° C.
  • the flexural strengths of the test objects produced with different variants of the binder systems I to III were determined as a function of different parameters (point in time after the end of curing, storage time of the molding material mixture before molding, storage conditions of the test specimens produced, size coating). Each determination was carried out on a specially manufactured test piece. The results of the measurements are compiled in Tables 1 and 2 below. Therein mean:
  • B-1 h Test specimen immersed in the sizing composition immediately after hardening, stored in the digester at room temperature, tested after 1 hour.
  • B-24h test specimen immersed in the composition of the sizing agent immediately after hardening, stored in the digester at room temperature, tested after 24 hours.
  • B-72h test specimen immersed in the composition of the sizing agent immediately after hardening, stored in the dump at room temperature, tested after 72 hours.
  • D-1 h Test specimen immersed in the composition of the size immediately after hardening, dried in an oven at 150 ° C. for 1 hour, tested after cooling to room temperature.
  • the sizing composition contains water as the carrier liquid and particles of aluminum silicate as the refractory material.
  • F-24h Test specimen stored immediately after curing at 100% relative humidity at room temperature for 24 hours and tested immediately after removal from storage.
  • F-72h test specimen stored immediately after curing at 100% relative humidity at room temperature for 72 hours and tested immediately after removal from storage
  • glycine as amino acid e) in component (iii) reduced formaldehyde emissions by approx. 20 to 50% with sufficient flexural strength.
  • the amount of amino acid e) added is preferably 0.1 to 3 parts by weight, particularly preferably 0.25 to 2 parts by weight, based on 100 parts by weight of the basic molding material (see Table 1).
  • the amino acid e) was added in pure form (variant 1), or as part of a mixture with a basic molding material (variant 2) or as part of a mixture with constituents of conventional additive mixtures for Molding material mixtures (variants 3, 4a, 4b), see Table 3.
  • the addition of the amino acid e) as part of a mixture with one or more other ingredients f) that are contained in the desired molding material mixture anyway (e.g. the respective molding base material, or the respective phenolic resin component), or are usually added to the desired molding material mixture (e.g. additive mixtures to avoid casting defects), has practical advantages because the addition and metering of the amino acid e) is made easier.
  • Table 1 Test results for binder system I without component (iii) or with component (iii) according to variant 1
  • Table 2 Test results of the binder systems I (different test specimens than in Table 1), II and III without component (iii) or with component (iii) according to variant 1
  • Table 3 Formaldehyde emissions from test specimens produced with binder system I with different variants of component (iii)

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)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Mold Materials And Core Materials (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Polyurethanes Or Polyureas (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Binders And Loading Units For Sheaves (AREA)

Abstract

L'invention concerne un système de liant, s'utilisant en particulier dans un procédé du groupe composé du procédé polyuréthane boîte froide et du procédé polyuréthane durcissant à froid.
EP20712465.2A 2019-03-08 2020-03-09 Piégeur de formaldéhyde pour systèmes de liants Pending EP3934826A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102019106021.4A DE102019106021A1 (de) 2019-03-08 2019-03-08 Formaldehyd-Fänger für Bindemittelsysteme
PCT/EP2020/056210 WO2020182724A1 (fr) 2019-03-08 2020-03-09 Piégeur de formaldéhyde pour systèmes de liants

Publications (1)

Publication Number Publication Date
EP3934826A1 true EP3934826A1 (fr) 2022-01-12

Family

ID=66442580

Family Applications (1)

Application Number Title Priority Date Filing Date
EP20712465.2A Pending EP3934826A1 (fr) 2019-03-08 2020-03-09 Piégeur de formaldéhyde pour systèmes de liants

Country Status (11)

Country Link
US (1) US11981770B2 (fr)
EP (1) EP3934826A1 (fr)
JP (1) JP7466560B2 (fr)
KR (1) KR20210135573A (fr)
CN (1) CN113573825A (fr)
BR (1) BR112021017468A2 (fr)
CA (1) CA3132226A1 (fr)
DE (2) DE102019106021A1 (fr)
EA (1) EA202192451A1 (fr)
MX (1) MX2021010777A (fr)
WO (1) WO2020182724A1 (fr)

Family Cites Families (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1222949A (fr) * 1958-04-22 1960-06-14 Polygram Casting Co Ltd Compositions thermodurcissables à base de sous-produits du sucre utilisables notamment pour la fabrication de moules de fonderie
US4197219A (en) 1979-01-17 1980-04-08 Lord Corporation Aqueous polyurethane-phenolic-formaldehyde resin emulsions for use as adhesives, primers and surface coatings
IT1141138B (it) 1980-12-16 1986-10-01 Montedison Spa Processo per la conversione di gruppi isocianici in gruppi carbodiimmidici e/o uretoniminici
DE19925115A1 (de) 1999-06-01 2000-12-07 Huettenes Albertus Bindemittelsystem für Formstoff-Mischungen zur Herstellung von Formen und Kernen
US6291578B1 (en) 1999-12-16 2001-09-18 Bayer Corporation Blocked polyisocyanates containing phenolic groups
JP3350532B1 (ja) 2001-09-28 2002-11-25 コニシ株式会社 水性固形接着剤および該水性固形接着剤による接着方法
DE10244442A1 (de) * 2002-09-24 2004-04-01 Schülke & Mayr GmbH Emissionsarme Formaldehyd-Depot-Zubereitungen und deren Verwendung
DE102005058835A1 (de) 2005-12-09 2007-06-14 Bayer Materialscience Ag Verfahren zur Herstellung von Carbodiimid- und/oder Uretonimin-Gruppen enthaltenden Polyisocyanaten
JP2008183580A (ja) 2007-01-29 2008-08-14 Kobe Rikagaku Kogyo Kk 鋳型用樹脂組成物、鋳型用粘結剤および鋳型の製造方法
DE102007012660B4 (de) 2007-03-16 2009-09-24 Chemex Gmbh Kern-Hülle-Partikel zur Verwendung als Füllstoff für Speisermassen
DE102008055042A1 (de) 2008-12-19 2010-06-24 Hüttenes-Albertus Chemische Werke GmbH Modifizierte Phenolharze
CN101524737B (zh) 2009-04-10 2010-12-29 苏州市兴业铸造材料有限公司 有色铸造用酚尿烷冷芯盒粘结剂及制备方法
DE102009032668A1 (de) 2009-07-09 2011-01-13 Hüttenes-Albertus Chemische Werke GmbH Schlichte zur Herstellung von Formüberzügen
JP5684482B2 (ja) 2010-02-18 2015-03-11 旭有機材工業株式会社 ポリウレタンフォーム用発泡性組成物並びにポリウレタンフォーム
GB201016565D0 (en) * 2010-10-01 2010-11-17 Dynea Oy Low free formaldehyde resins for abrasive products
DE102010051567A1 (de) 2010-11-18 2012-05-24 Ashland-Südchemie-Kernfest GmbH Bindemittel auf Polyurethanbasis zur Herstellung von Kernen und Gießformen unter Verwendung von Isocyanaten enthaltend eine Urethonimin- und/oder Carbodiimid-Gruppe, eine Formstoffmischung enthaltend das Bindemittel und ein Verfahren unter Verwendung des Bindemittels
DE102012200967A1 (de) 2012-01-24 2013-07-25 Chemex Gmbh Speiser und formbare Zusammensetzung zu deren Herstellung enthaltend kalzinierte Kieselgur
DE202012013467U1 (de) 2012-02-09 2017-01-30 HÜTTENES-ALBERTUS Chemische Werke Gesellschaft mit beschränkter Haftung Cold-Box-Bindemittelsysteme und Mischungen zur Verwendung als Additive für solche Bindemittelsysteme
JP6026891B2 (ja) * 2012-03-09 2016-11-16 花王株式会社 鋳型造型用粘結剤組成物
EP3046945B1 (fr) * 2013-09-19 2023-12-13 Dow Global Technologies LLC Composition activatrice, système adhésif la comprenant, et procédé de collage de substrats l'utilisant
MX2017013161A (es) * 2015-04-14 2018-02-21 Huettenes Albertus France Composicion de resina fenolica para uso en el proceso de caja fria y/o autofraguante de poliuretano y correspondientes sistemas aglomerantes de dos componentes, usos y procesos.
MX2018005270A (es) 2016-01-05 2018-08-01 Mitsui Chemicals Inc Composicion de policarbodiimida, metodo para producir la composicion de policarbodiimida, composicion de dispersion acuosa, composicion en solucion, composicion de resina, y resina curada.
DE102016203896A1 (de) 2016-03-09 2017-09-14 HÜTTENES-ALBERTUS Chemische Werke Gesellschaft mit beschränkter Haftung Zweikomponenten-Bindemittelsystem für den Polyurethan-Cold-Box-Prozess
DE102016123051A1 (de) 2016-11-29 2018-05-30 HÜTTENES-ALBERTUS Chemische Werke Gesellschaft mit beschränkter Haftung Aminosäure enthaltende Formstoffmischung zur Herstellung von Formkörpern für die Gießereiindustrie
DE102016123621A1 (de) 2016-12-06 2018-06-07 Ask Chemicals Gmbh Polyurethan Bindemittel mit verbesserter Fließfähigkeit
DE102016125700A1 (de) 2016-12-23 2018-06-28 Ask Chemicals Gmbh Bindemittel auf Basis von Phenolharzen vom Benzylethertyp enthaltend freies Phenol und freie Hydroxybenzylalkohole
DE102016125702A1 (de) 2016-12-23 2018-06-28 Ask Chemicals Gmbh Komponentenystem zur Herstellung von Kernen und Formen
DE102018118291A1 (de) 2018-07-27 2020-01-30 HÜTTENES-ALBERTUS Chemische Werke Gesellschaft mit beschränkter Haftung Schlichtezusammensetzung zur Reduzierung von Formaldehyd-Emissionen

Also Published As

Publication number Publication date
JP7466560B2 (ja) 2024-04-12
KR20210135573A (ko) 2021-11-15
MX2021010777A (es) 2021-09-30
WO2020182724A1 (fr) 2020-09-17
CN113573825A (zh) 2021-10-29
CA3132226A1 (fr) 2020-09-17
EA202192451A1 (ru) 2021-11-26
JP2022523980A (ja) 2022-04-27
US11981770B2 (en) 2024-05-14
DE202019102078U1 (de) 2019-04-23
BR112021017468A2 (pt) 2021-11-16
US20220169780A1 (en) 2022-06-02
DE102019106021A1 (de) 2020-09-10

Similar Documents

Publication Publication Date Title
DE69629464T2 (de) Phenolharz-zusammensetzungen mit verbesserter schlagfestigkeit
EP2812374B1 (fr) Systèmes liants en boîte-froide et mélanges pour utilisation comme additifs pour de tels systèmes
EP3191239A1 (fr) Système de liant à deux composants pour procédé "polyuréthane-boîte froide"
WO2017153474A1 (fr) Système de liant à deux composants pour le procédé boîte froide polyuréthane
DE202011110579U1 (de) Sulfonsäure enthaltendes Bindemittel für Formstoff-Mischungen zur Herstellung von Formen und Kernen
EP3737707A1 (fr) Liant résine phénolique à teneur réduite en formaldéhyde
DE102015107016A1 (de) Verfahren zur Reduzierung von freiem Formaldehyd in Benzylether-Harzen
EP3829798A1 (fr) Composition de poteyage servant à réduire des émissions de formaldéhyde
EP3898752A1 (fr) Composition isocyanate et système liant contenant ladite composition isocyanate
WO2016008467A1 (fr) Co-catalyseurs pour liants polyuréthane-boîte froide
EP3934826A1 (fr) Piégeur de formaldéhyde pour systèmes de liants
EP3558559B1 (fr) Système d'éléments destiné à la fabrication de noyaux et de moules
EP3265254A1 (fr) Procédé de durcissement de liants au polyuréthane dans des mélanges de matériaux ce moulage par introduction d'amines tertiaires et de solvants et kit pour la mise en uvre du procédé
EP3559065B1 (fr) Résine phénolique destinée à être utilisée dans le composant résine phénolique d'un système de liant bicomposant
DE1583521C (de) Massen zum Herstellen von Gießereikernen und -formen

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: UNKNOWN

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20211008

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)