DE102018121769A1 - Process for producing a metallic casting or a hardened molded part using an aliphatic binder system - Google Patents

Abstract

A method is described (i) for producing a metallic casting and / or (ii) for producing a hardened molding, selected from the group consisting of casting mold, core and feeder, for use in casting metallic castings, and a molding material mixture for use therein Method. The use of an aliphatic polymer which is crosslinked by one or more aliphatic polyisocyanates and contains hydroxyl groups is also described as a binder of a molded part for use in the casting of metallic castings. Also described is a hardened molded part for use in the casting of metallic castings, including a green part which is stable on green, and which can preferably be produced by the process according to the invention. It also describes the use of biopolymers from the group of poly-D-glucosamines as binders or binder components for the production of a green molded part in the foundry industry.

Description

The present invention relates to a process (i) for producing a metallic casting and / or (ii) for producing a hardened molding, selected from the group consisting of casting mold, core and feeder, for use in casting metallic castings, and a molding material mixture, in particular for use in this procedure.

Furthermore, the present invention relates to the use of an aliphatic polymer, which is crosslinked by one or more aliphatic polyisocyanates and comprises hydroxyl groups, as a binder of a molded part for use in the casting of metallic castings.

The present invention likewise relates to a hardened molded part for use in the casting of metallic castings, including a molded part which is stable on green, and preferably can be produced by the process according to the invention.

The present invention also relates to the use of biopolymers from the group of the poly-D-glucosamines as binders or binder components for the production of a green-stable molded part in the foundry industry.

Foundry molded parts used in metal casting (hereinafter also referred to as “molded parts”), in particular cores, molds and feeders (including feeder caps and wrappings or feeder sleeves), consist regularly of a refractory base material which, depending on the application, contains one or more refractory solids , for example quartz sand, and / or one or more particulate light fillers, for example spheres from fly ash, and a suitable binder which gives the molded part sufficient mechanical after removal from the mold (for example a molded part box such as a core box or a molded box, see below) Gives strength. In the uncured state, the mixture of molding base material and binder, which may also contain other additives, is referred to as a “molding material mixture”.

Refractory solids are preferably particulate and in a free-flowing form, so that after incorporation into a molding material mixture they can be filled into a suitable hollow mold (the molding tool, see above) and compressed there. For this purpose, feeders and cores are usually introduced into a mold in core shooters under pressure, i.e. "Shot". Smaller moldings are often also shot, while larger moldings, especially larger molds, are usually molded in a mold box by stamping. In general, all molded parts can also be produced by stamping in appropriate shapes, for example using the hand molding method. In order to obtain shootable or tampable molding material mixtures, their moisture content, and in the case of water-based binders in particular their water content, must be set accordingly so that the molding material mixture has sufficient dimensional stability for the corresponding molding process, or the ratio of the liquid components of the molding material mixture to their solid content Components are set accordingly.

Molded parts such as molds, cores and feeders must meet various typical foundry requirements. The type and extent of the fulfillment of these requirements are essentially determined by the binder used to manufacture them:

After the production of a molded part, i.e. immediately after the molded part has been removed from the production tool, the molded part should have the highest possible strength. The strengths at this point in time (“initial strength”, also referred to as “green stability”, see also below) are particularly important for the safe handling of cores, molds or feeders when they are removed from the manufacturing tool.

A high so-called final strength (i.e. the strength after the molded part has completely hardened) and a high temperature resistance of a molded part during the actual metal casting are important, especially for cores and molds, so that the molded part does not deform under the weight of the cast metal (i.e. a good one Retains its shape during the casting process, also referred to as "casting resistance") and the metal casting produced with it can be made as far as possible without casting defects. In this context, it is also important that the molded parts used have as clean or smooth a surface as possible without distortions or the like, since otherwise surface defects of the molded parts can be transferred to the surfaces of the metal castings produced with them.

Furthermore, the high resistance of the molded parts to aqueous moisture is a great advantage. In general, such a high level of moisture resistance allows the molded parts to be stored for a longer period of time, even under demanding climatic conditions (warm, humid climate) and ideally over several days or weeks, which facilitates the production of molded parts in stock and their storage. As a result, the industrial production of metal castings with these molded parts gains considerable flexibility. It has also been shown that with all molded parts used in metal casting, in particular with feeders, water absorption (for example during their storage due to the absorption of moisture from the air) can lead to the corresponding water deposits at the high temperatures of the metal casting Form vapor bubbles, which can lead to the formation of voids in the metal casting, which then makes it unusable. In extreme cases, sudden water vapor formation can even lead to explosions. A high level of moisture resistance of the molded parts is also advantageous, since it allows, for example, their use with different types of size and in particular also with water-based sizes. Finishes are release agents on a ceramic basis, which in certain cases are intended to prevent direct contact between molded parts, for example cores, and the molten metal, so that they can better withstand the high thermal loads during metal casting.

In view of a high metal casting quality, it is also desirable that molded parts withdraw as little thermal energy from the molten metal, e.g. by reactions of the binder, such as can occur in known melting reactions of water glass binders. Such a withdrawal of thermal energy can lead to premature solidification of the molten metal and thus to an incomplete casting. This characterization of a binder by its properties to absorb thermal energy itself is also referred to as its "quenching behavior". Particularly in the case of feeders, a particularly good thermal insulation effect is desired or necessary in order to keep the molten metal liquid as long as possible during the casting of the metal and to achieve the lowest possible formation of voids in the metal casting, any void formation occurring as far as possible outside the finished metal casting ( only in the feeder).

After the casting process has taken place, a molded part should then decompose as much as possible under the influence of the heat emitted by the casting metal in such a way that it loses its mechanical strength, that is to say the cohesion between individual particles of the base material is lost. In the ideal case, the molded part then disintegrates into fine particles of the basic molding material, which can be removed from the metal casting effortlessly and with as little residue as possible. If the molded part is a core, such advantageous disintegration properties lead to a particularly good removability of a metal casting.

In this context, it is also particularly desirable that the decomposition of the molded part, which is usually accompanied by thermal decomposition of the binder, is as emission-free as possible, i.e. without the emission of unpleasant smells and / or even substances that are hazardous to health, in order to minimize, reduce or ideally exclude any nuisance or health risks to the personnel working in the foundry. Such an impairment due to unpleasant smells and / or substances hazardous to health can occur especially when casting with the hot molten metal, in which case the feeders, which usually protrude from the mold, are the main cause, but also after the metal casting has solidified, if this is freed from the mold ("unpacked" or "demolded").

Various organic and inorganic binders are already known for the production of molded parts for the foundry industry, all of which have limitations or disadvantages typical of them.

In the field of organic binders and binder systems, those are known which can be cured by cold or hot processes.

In the case of thermosetting processes, the molding material mixture is shaped e.g. heated to a sufficiently high temperature by the heated molding tool in order to drive off the solvent contained in the binder and / or to initiate a chemical reaction by means of which the binder is cured. An example of such a thermosetting process is the so-called "hot box process". Today it is mainly used in the large-scale production of cores.

Cold-hardening processes are processes which are carried out essentially without heating the mold used for core production, usually at room temperature or at a temperature caused by any, usually chemical, reaction. The curing takes place, for example, by a gas which is passed through the molding material mixture to be hardened and thereby triggers a corresponding chemical reaction. An example of such a cold-hardening process is the so-called “cold box process”, which is used extensively in the foundry industry today.

According to the prior art, both hot-box processes and cold-box processes use organic binders based on phenolic resin. Irrespective of their exact composition, these have the disadvantage that, in the event of their desired decomposition, they are partly caused by the temperatures prevailing during metal casting. considerable amounts of pollutants such as Release benzene, toluene and xylene (also abbreviated "BTX"). In addition, the metal casting of such organic binders generally leads to undesirable odor and smoke or smoke emissions. In some such binder systems, undesirable emissions even occur during the manufacture and / or storage of the molded parts.

As an alternative to the aforementioned organic binders, corresponding inorganic binders are known which do not have the aforementioned phenomenon of releasing undesirable odors or pollutants during metal casting, or do so only to a much lesser extent. An example of such an inorganic binder is water glass. The corresponding molding material mixture essentially consists of molding material, for example quartz sand, and water glass (as an aqueous solution of alkali silicates). The shaped molding material mixtures are cured, for example, by gassing with CO ₂ .

However, the use of such inorganic binders is associated with other, typical disadvantages: moldings made from inorganic binders often have only low strengths. This is particularly evident immediately after the molded part has been removed from the tool. In addition, their often low moisture resistance leads to a limited shelf life of the molded parts produced with them. In addition, inorganic binders often do not have sufficient disintegration properties, which means that time-consuming reworking of the metal castings produced with corresponding molded parts is necessary. It is also known that waterglass-bound feeders generally have less good insulation properties than feeders bound with organic binders. Finally, inorganic binder systems such as water glass are also known to noticeably absorb heat energy when metal is poured, i.e. consume, whereby the metal melt solidifies relatively early so that casting errors can occur. This is especially true for iron and steel casting with the high casting temperatures required there.

• Das Dokument DE 10 2007 031376 A1 beschreibt ein alternatives Cold-Box-Verfahren mit Rohölen.
• Das Dokument DE 196 154 00 A1 beschreibt ein Polymer, seine Verwendung als Bindemittel zur Herstellung keramischer Grünkörper und ein Verfahren zur Herstellung von keramischen Gegenständen.
• In dem Dokument JPH 061 57860 A werden Wasser-resistente Zusammensetzungen beschrieben.
• In dem Dokument JPS 61 276813 A werden härtbare Zusammensetzungen angegeben.
• Das Dokument EP 677 346 A2 betrifft ein Gießverfahren unter Verwendung eines Gießkerns aus synthetischem Harz, einen synthetischen Harzkern sowie ein Gusswerkstück.
• In dem Dokument WO 96/26231 A1 wird ein chemischer Binder beschrieben, umfassend einen Ester-basierten Polyol, ein Isocyanat und einen Katalysator.
• Das Dokument WO 2011/044003 A2 betrifft auf Lignit-Urethan basierende Harze für Gusssand mit verbesserter Leistung.
• In dem Dokument WO 2017/071695 A1 werden Phenol-Formaldehydharz-freie Bindemittel für Gießerei-Formsande beschrieben.

A number of organic binders as well as processes for the production of molded parts using such binders are already discussed in the prior art:

• The document DE 10 2007 031376 A1 describes an alternative cold box process with crude oils.
• The document DE 196 154 00 A1 describes a polymer, its use as a binder for the production of ceramic green bodies and a process for the production of ceramic objects.
• JPH 061 57860 A describes water-resistant compositions.
• In document JPS 61 276813 A curable compositions are given.
• The document EP 677 346 A2 relates to a casting method using a synthetic resin casting core, a synthetic resin core and a casting workpiece.
• In the document WO 96/26231 A1 describes a chemical binder comprising an ester-based polyol, an isocyanate and a catalyst.
• The document WO 2011/044003 A2 concerns lignite-urethane based resins for cast sand with improved performance.
• In the document WO 2017/071695 A1 Phenol-formaldehyde resin-free binders for foundry molding sands are described.

• - eine hohe, jedenfalls für praktische Einsatzzwecke ausreichende, Anfangsfestigkeit der nach dem Verfahren hergestellten Formteile;
• - eine hohe Endfestigkeit der nach dem Verfahren hergestellten Formteile;
• - eine hohe Abgussfestigkeit bzw. Temperaturbeständigkeit der nach dem Verfahren hergestellten Formteile;
• - eine saubere bzw. glatte Oberfläche der nach dem Verfahren hergestellten Formteile;
• - eine möglichst hohe Feuchtigkeitsbeständigkeit bzw. eine möglichst hohe Wasserfestigkeit der nach dem Verfahren hergestellten Formteile, so dass u.a. eine möglichst gute bzw. lange Lagerfähigkeit der Formteile auch bei unterschiedlichen Klimabedingungen resultiert und/oder diese mit wasserbasierten Schlichten eingesetzt werden können;
• - eine möglichst geringe Wärmeenergieaufnahme und im Idealfall eine gute Wärmeisolierungswirkung beim Metall-Abguss der nach dem Verfahren hergestellten Formteile;
• - eine möglichst geringe Emission von Geruchs- und/oder Schadstoffen sowie von Rauch oder Qualm der nach dem Verfahren hergestellten Formteile, insbesondere unter den Bedingungen eines Metall-Abgusses, sowohl beim Abguss von Leichtmetallen und deren Legierungen als auch beim Eisen- und Stahlabguss;
• - der wenigstens teilweise Einsatz nachwachsender Ausgangsstoffe;
• - einen möglichst geringen apparativen Aufwand bei der Durchführung des Verfahrens, insbesondere eine Durchführbarkeit (auch) ohne heizbare Werkzeuge (d.h. durchführbar mindestens ähnlich einem bekannten Cold-Box-Herstellungsverfahren und mit einer entsprechenden apparativen Ausstattung).

However, even in view of the prior art, there is still a need for a method for producing metallic castings or for producing hardened molded parts for use in casting metallic castings, which realizes one, more and, ideally, all of the following advantageous properties:

• - A high, at least for practical purposes, sufficient initial strength of the molded parts produced by the process;
• - A high final strength of the molded parts produced by the process;
• - a high casting resistance or temperature resistance of the molded parts produced by the process;
• - A clean or smooth surface of the molded parts produced by the process;
• - The highest possible moisture resistance or the highest possible water resistance of the molded parts produced by the process, so that among other things the best possible or long shelf life of the molded parts results even under different climatic conditions and / or these can be used with water-based sizes;
• - The lowest possible heat energy absorption and ideally a good heat insulation effect when casting metal from the molded parts produced by the process;
• - The lowest possible emission of odors and / or pollutants as well as smoke or smoke from the molded parts produced by the process, in particular under the conditions of a metal casting, both when casting light metals and their alloys and when casting iron and steel;
• - the at least partial use of renewable raw materials;
• the least possible outlay in terms of apparatus when carrying out the method, in particular feasibility (also) without heatable tools (ie feasible at least similar to a known cold box production method and with appropriate apparatus).

Furthermore, there is also a need for a binder for a molded part in the casting of metallic castings, which has or effects one, several and, ideally, all of the advantageous relevant properties specified above, and for a molding material mixture for use in such a process. There is also a need for a molded part which has one, several and, ideally, all of the relevant properties mentioned in connection with the method described above. There is also still a need for a binder which allows green-stable molded parts to be produced for use in the foundry industry, especially in terms of flexible design of corresponding manufacturing processes.

It was therefore a primary object of the present invention to provide a method for producing a metallic casting or for producing a hardened molded part for use in casting metallic castings, which process brings about one, more and, ideally, all of the advantageous properties stated above or has and a molding material mixture va for use in the aforementioned method.

It was a further object of the present invention to provide a binder for use in a molded part in the casting of metallic castings, which has or effects one, several and ideally all of the advantageous relevant properties indicated above.

A specific object of the present invention was also to provide a hardened molded part for use in the casting of metallic castings, which has one, several and ideally all of the relevant properties mentioned in connection with the method described above.

In addition, it was an object of the present invention to provide a binder which also makes it possible to produce moldings which are green-stable for use in the foundry industry, if possible at room temperature.

• V1) Herstellen einer Formstoffmischung, umfassend die folgenden Bestandteile (oder bestehend aus den folgenden Bestandteilen):
  1. a) mindestens einen Formgrundstoff,
  2. b) ein oder mehrere aliphatische Polymere jeweils umfassend Hydroxygruppen enthaltende Struktureinheiten der Formel I -CH₂-CH(OH)- (I),
  3. c) als Härterkomponente, ein oder beide Bestandteile ausgewählt aus der Gruppe bestehend aus:
     • c1) ein oder mehrere Biopolymere ausgewählt aus der Gruppe der Poly-D-Glucosamine und
     • c2) ein oder mehrere Polyisocyanate, als Vernetzungsmittel für Hydroxygruppen des bzw. der aliphatischen Polymere;
     und
  4. d) Wasser;
• V2) Formen der Formstoffmischung, und anschließend
• V3) Härten der geformten Formstoffmischung oder eines daraus entstandenen, nicht gehärteten Folgeproduktes in einem oder mehreren Schritten, so dass ein gehärtetes Formteil resultiert.

It has now surprisingly been found that the primary object and further objects and / or partial objects of the present invention are achieved by a method i) according to the invention for producing a metallic casting and / or ii) for producing a hardened molded part selected from the group consisting of a mold , Core and feeder, for use in casting metallic castings, with the following steps:

• V1) Preparation of a molding material mixture comprising the following constituents (or consisting of the following constituents):
  1. a) at least one basic molding material,
  2. b) one or more aliphatic polymers each comprising structural units of the formula I containing hydroxyl groups - CH ₂ -CH (OH) - (I),
  3. c) as hardener component, one or both components selected from the group consisting of:
     • c1) one or more biopolymers selected from the group of poly-D-glucosamines and
     • c2) one or more polyisocyanates, as crosslinking agents for hydroxyl groups of the aliphatic polymer (s);
     and
  4. d) water;
• V2) shaping the molding material mixture, and then
• V3) hardening the molded molding material mixture or a resulting, non-hardened secondary product in one or more steps, so that a hardened molded part results.

The invention and combinations of preferred parameters, properties and / or components of the present invention which are preferred according to the invention are defined in the appended claims. Preferred aspects of the present invention are also specified or defined in the following description and in the examples.

With the method according to the invention, including its variants and preferred variants, hardened molded parts can be produced for the foundry industry, in particular molds, cores and feeders (insulating feeders and exothermic feeders, including feeder caps and feeder sleeves), which have a large number of advantageous properties. Depending on the design of the method (or its variants or preferred variants), one, several or, ideally, all of the advantageous properties listed above can be achieved. All variants and configurations of the method according to the invention have in common that only low emissions of odor and / or pollutants as well as of smoke or smoke occur in them. In preferred embodiments of the method according to the invention, only very low emissions of odorous and / or pollutants as well as smoke or smoke occur. Furthermore, all variants and configurations of the method according to the invention have in common that the molded parts produced thereafter have little tendency to absorb thermal energy and exhibit advantageous quenching behavior.

In the process according to the invention specified above, the molding material mixture in step V1) is preferably produced by intensively mixing the components a) to d) with one another in order to obtain a homogeneous distribution in the molding material mixture. The components are mixed with one another in a manner known per se, for example with a stirrer suitable for this purpose, for example a paddle stirrer. For preferred configurations of components a) to c) see below.

In step V2) the molding material mixture is formed into a three-dimensional structure, selected from the casting mold, core and feeder (including feeder caps and feeder sleeves). Step V2) is preferably carried out in a molding tool.

In the context of the present invention, the term “molding tool” denotes any tool which can be used in the foundry industry for shaping molded parts, preferably selected from the group consisting of casting mold, core and feeder (including feeder caps and feeder sleeves), in particular molded part boxes (including Molding boxes and core boxes) and shooting machines for shooting molded parts, in particular core shooting machines.

If the molding in step V2) is carried out in a shooting machine, the ratio of total moisture content to total solids content in the molding material mixture is preferably set before or during molding of the molding material mixture such that the molding material mixture can be fired in a shooting machine or in a molding box is stompable. This setting is readily possible for the person skilled in the art.

Step V3) of the method according to the invention specified above comprises hardening the molded molding material mixture or a non-hardened secondary product resulting therefrom, so that a hardened molded part results. The hardening in step V3) preferably results in an at least dimensionally hardened molded part. In this context, “dimensionally stable” means that a molded part with this property retains its shape, even after the mold has been removed, for example, that it can be handled at least without loss or impairment of its shape and, for example, can be transported to a further processing site at the place of manufacture.

• V31) Ausfällen von zumindest Anteilen der ein oder mehreren Biopolymere (in der geformten Formstoffmischung und/oder dem daraus entstandenen, nicht gehärteten Folgeprodukt) so dass ein grünstandsfestes Formteil resultiert (Näheres dazu siehe unten),
• V32) Behandeln der geformten Formstoffmischung und/oder des daraus entstandenen, nicht gehärteten Folgeproduktes und/oder (sofern vorher Schritt V31) durchgeführt wurde) des grünstandsfesten Formteils durch Erhitzen und/oder Entfernen von Wasser (Näheres dazu siehe unten), und
• V33) Vernetzen lassen von Hydroxygruppen des bzw. der aliphatischen Polymere der Formel I (Bestandteil b)) mit Isocyanat-Gruppen der Polyisocyanate (Bestandteil c1), soweit vorhanden), vorzugsweise der aliphatischen Polyisocyanate, in der geformten Formstoffmischung und/oder in dem daraus entstandenen, nicht gehärteten Folgeprodukt und/oder in dem grünstandsfesten Formteil (sofern vorher Schritt V31) durchgeführt wurde), so dass als gehärtetes Formteil ein vernetztes Formteil resultiert (Näheres dazu siehe unten).

In the context of the present invention, the hardening of the shaped molding material mixture or a non-hardened secondary product resulting therefrom in step V3) comprises one, two or all three steps (in each case as far as applicable in a specific variant or embodiment of the method according to the invention) selected from the group consisting of :

• V31) Precipitation of at least portions of the one or more biopolymers (in the molded molding material mixture and / or the resulting, non-hardened secondary product), so that a green component is obtained (for further details see below),
• V32) treating the shaped molding material mixture and / or the resulting, not hardened secondary product and / or (if step V31 was carried out beforehand) the green stand-resistant molded part by heating and / or removing water (for details see below), and
• V33) Crosslinking of hydroxyl groups of the aliphatic polymer (s) (formula b) (component b)) with isocyanate groups of the polyisocyanates (component c1), if present), preferably the aliphatic polyisocyanates, in the molded molding material mixture and / or in it The resulting, non-hardened secondary product and / or in the green-stable molded part (if step V31 was carried out beforehand), so that a cross-linked molded part results as a hardened molded part (for details see below).

In the context of the present invention and in accordance with the usual understanding in the professional world, the term “green-stable” means “dimensionally stable or dimensionally stable hardened or pre-hardened, but not yet hardened or hardened sufficiently for the intended purpose”. A green part that is stable on green has, for example, a hardness that is sufficient for removal from a molding tool or for transfer to a next processing step, but usually still does not have sufficient hardness for the ultimately intended purpose, here for use in the production of a metallic casting. The production of a green part that is stable in the process according to the invention is preferred, for example, when the process is carried out without heatable molds: a green part that is stable in the green can then be treated further with or without the mold used for its production, in particular according to step V32) and / or Step V33) of the method according to the invention, for example in a conventional drying oven. In order to produce a green part that is resistant to green standing in step V3) or V31), the presence of constituent c1), one or more biopolymers selected from the group of poly-D-glucosamines, in the molding material mixture is required by the process according to the invention. A green-stable molded part obtained after step V31) represents a hardened molded part in the sense of the present invention.

In the preferred embodiments of the process according to the invention, in which the hardening in step V3) comprises step V31), at least proportions, preferably the total amount, of the one or more biopolymers used in the process (preferably the chitosan, see below) are obtained from the aqueous Shares of the molded molding material mixture or a resulting, not hardened secondary product precipitated. This is preferably done in a manner known per se by increasing the pH of these aqueous fractions. The pH can be increased in any known manner, for example by adding aqueous alkali. The pH value of the aqueous portions of the shaped molding material mixture or of an uncured secondary product resulting therefrom is preferably increased by gassing with one or more alkaline compounds which are gaseous under the reaction conditions, preferably with one or more amines which are gaseous under the reaction conditions. The one or more of the several gaseous amines is preferably N, N, -dimethylpropyla-min. As a result of the increase in the pH in the molded molding material mixture or the resulting, uncured secondary product, which in each case contains the one or more biopolymers from the group of poly-D-glucosamines (preferably chitosan), at least portions of these biopolymers fall out of the aqueous ones Ingredients of the molded molding material mixture or the resulting, not hardened secondary product, so that a green-stable molded part results. The production of a green part that is resistant to green stands can be carried out in a manner known per se, in particular according to the step the hardening or hardening of a shaped molding material mixture (or a non-hardened secondary product resulting therefrom) in the cold box process: since no temperature increase (heating) is necessary to produce a green-stable molded part according to the process of the invention, this step can be carried out, for example, in one step known cold box tool can be performed. A cold box core shooter without a heating device is suitable for this, without having to make any noteworthy changes to it, since in the cold box process, for example, the step of curing the molded molding material mixture (or the resulting, non-hardened secondary product) is also preferred by gassing with a gaseous amine. In the aforementioned manner, green molds, cores and feeders can be produced using the method according to the invention.

The shaped molding material mixture (as obtained after step V2)) and / or a non-hardened secondary product resulting therefrom and / or a green-stable molded part (as obtained after step V31)) is preferably further treated according to step V32) (see below). A molded part produced by the method according to the invention usually already has sufficient hardness for use in producing a metallic casting after step V32) has been carried out. The treatment in step V3) or V32) is carried out by heating the molded molding material mixture and / or the resulting, not hardened secondary product and / or the green component that is resistant to green residue, and / or by removing water from the molding material mixture, secondary product or green component that is resistant to green residue ( as indicated above) achieved as described in more detail below.

As far as possible (ie if component c2), one or more polyisocyanates are present as crosslinking agents for hydroxyl groups of the aliphatic polymer (s) in the molding material mixture in step V1) and is desired, one after step V31) and / or after step V32 ) obtained (hardened) molded part in step V33) further converted into a crosslinked (hardened) molded part, by crosslinking hydroxyl groups of the aliphatic polymer (s) of formula I with isocyanate groups of the polyisocyanates. To produce a crosslinked molding in step V3) or V33), the presence of component c2), one or more polyisocyanates as crosslinking agents for hydroxyl groups of the aliphatic polymer or polymers, in the molding material mixture is required by the process according to the invention.

The crosslinking of the hydroxyl groups with the isocyanate groups in step V33) is preferably carried out by heating the molded molding material mixture and / or the resulting uncured follow-up product and / or the green-resistant molded part and the, preferably simultaneous, removal of water therefrom, so that if step V32) is carried out accordingly and component c2) is present in the molding material mixture, the hydroxyl groups are at least partially crosslinked with the isocyanate groups (step V33)). In variants of the method according to the invention, in which step V3) comprises both step V32) and step V33), the product or end product of the method according to the invention therefore results in a crosslinked (hardened) molded part, which is a hardened molded part in the sense of the present Represents invention. See below for details.

A cross-linked (hardened) molded part (as obtained after carrying out both steps V32) and step V33)) generally has sufficient hardness for use in the production of a metallic casting and additionally preferably has an advantageous high moisture resistance or high water resistance on. The initial strength, the final strength and the casting strength of such a crosslinked (hardened) molded part are generally particularly high.

• - die Formstoffmischung als Härterkomponente c) (mindestens) den Bestandteil c1), ein oder mehrere Biopolymere ausgewählt aus der Gruppe der Poly-D-Glucosamine, umfasst, und vorzugsweise (zusätzlich) den Bestandteil c2), ein oder mehrere Polyisocyanate, vorzugsweise aliphatische Polyisiocyanate, als Vernetzungsmittel für Hydroxygruppen des bzw. der aliphatischen Polymere, umfasst

und/oder (vorzugsweise „und“)

• - das Härten in Schritt V3) umfasst
  • V31) (bei Anwesenheit des Bestandteils c1)) das Ausfällen von zumindest Anteilen der ein oder mehreren Biopolymere, vorzugsweise durch Erhöhen des pH-Wertes der wässrigen Anteile der geformten Formstoffmischung, besonders bevorzugt durch Kontaktieren, vorzugsweise Begasen, mit einer alkalisch reagierenden gasförmigen Verbindung, ganz besonders bevorzugt durch Begasen mit einem gasförmigen Amin, so dass ein grünstandsfestes Formteil resultiert;
  und/oder (vorzugsweise „und“)
  • V32) das Behandeln der geformten Formstoffmischung und/oder des daraus entstandenen, nicht gehärteten Folgeproduktes und/oder (sofern vorher Schritt V31) durchgeführt wurde) des grünstandsfesten Formteils,
    • - durch Erhitzen der geformten Formstoffmischung und/oder des daraus entstandenen, nicht gehärteten Folgeproduktes und/oder des grünstandsfesten Formteils, vorzugsweise auf eine Temperatur im Bereich von 100 °C bis 300 °C, besonders bevorzugt im Bereich von 150 °C bis 250 °C und ganz besonders bevorzugt im Bereich von 180 °C bis 230 °C, und/oder (vorzugsweise „und“)
    • - durch Entfernen von Wasser aus der geformten Formstoffmischung und/oder aus dem daraus entstandenen, nicht gehärteten Folgeprodukt und/oder aus dem grünstandsfesten Formteil.

Preferred is a method according to the invention specified above, preferably a method (ii) according to the invention (preferably a method according to the invention designated above or below as preferred), wherein

• - The molding material mixture as hardener component c) comprises (at least) component c1), one or more biopolymers selected from the group of poly-D-glucosamines, and preferably (additionally) component c2), one or more polyisocyanates, preferably aliphatic polyisiocyanates , as a crosslinking agent for hydroxyl groups of the aliphatic polymer (s)

and / or (preferably "and")

• - the hardening in step V3)
  • V31) (in the presence of component c1)) the precipitation of at least portions of the one or more biopolymers, preferably by increasing the pH of the aqueous portions of the molded molding mixture, particularly preferably by contacting, preferably gassing, with an alkaline gaseous compound, very particularly preferably by gassing with a gaseous amine, so that a green-stable molded part results;
  and / or (preferably "and")
  • V32) the treatment of the shaped molding material mixture and / or the resulting, non-hardened secondary product and / or (if step V31 was carried out beforehand) the molded part which is stable on green,
    • by heating the shaped molding material mixture and / or the resulting, not hardened secondary product and / or the green part which is resistant to green standing, preferably to a temperature in the range from 100 ° C. to 300 ° C., particularly preferably in the range from 150 ° C. to 250 ° C. and very particularly preferably in the range from 180 ° C. to 230 ° C., and / or (preferably “and”)
    • - By removing water from the molded molding material mixture and / or from the resulting, non-hardened secondary product and / or from the green-proof molded part.

In many cases, an embodiment of the method according to the invention specified above is preferred, the molding material mixture as hardener component c) comprising only component c1), one or more biopolymers selected from the group of poly-D-glucosamines (ie the hardener component c) comprises in this embodiment does not include component c2), one or more polyisocyanates). In this embodiment of the method according to the invention, which is preferred in many cases, step V31), the precipitation of at least portions of the one or more biopolymers, is preferably carried out to produce a green stand-resistant molded part. In this embodiment of the method according to the invention, step V32) is preferably carried out either with the shaped molding material mixture (as obtained after step V2), then without carrying out step V31 beforehand)) or - preferably - with the green part which is resistant to green (as obtained after step V31), then carried out in addition to and after the previous step V31)).

• - Gefriertrocknen der geformten Formstoffmischung und/oder des daraus entstandenen, nicht gehärteten Folgeproduktes und/oder des grünstandsfesten Formteils,
• - Vakuumtrocknen der geformten Formstoffmischung und/oder des daraus entstandenen, nicht gehärteten Folgeproduktes und/oder des grünstandsfesten Formteils, und
• - Erhitzen der geformten Formstoffmischung und/oder des daraus entstandenen, nicht gehärteten Folgeproduktes und/oder des grünstandsfesten Formteils (und Entfernen von Wasser aus der geformten Formstoffmischung und/oder aus dem daraus entstandenen, nicht gehärteten Folgeprodukt und/oder aus dem grünstandsfesten Formteil);

ausgeführt. Vorzugsweise wird das Entfernen von Wasser in Schritt V32) (in allen Varianten des erfindungsgemäßen Verfahrens, welche den Schritt V32) und das Entfernen von Wasser umfassen) ausgeführt durch Erhitzen der geformten Formstoffmischung und/oder des daraus entstandenen, nicht gehärteten Folgeproduktes und/oder des grünstandsfesten Formteils und (vorzugsweise gleichzeitiges) Entfernen von Wasser aus der geformten Formstoffmischung und/oder aus dem daraus entstandenen, nicht gehärteten Folgeprodukt und/oder aus dem grünstandsfesten Formteil.The removal of water in step V32) (in all variants of the method according to the invention, which include step V32) and the removal of water) is selected by one, two or by all three measures from the group consisting of:

• Freeze-drying the shaped molding material mixture and / or the resulting, not hardened secondary product and / or the green part which is stable on greenery,
• - Vacuum drying of the shaped molding material mixture and / or of the resulting, not hardened secondary product and / or of the molded part which is stable on green, and
• - heating the molded molding material mixture and / or the resulting uncured secondary product and / or the green-resistant molded part (and removing water from the molded molding material mixture and / or the resulting uncured secondary product and / or the green-stable molded part);

executed. Preferably, the removal of water in step V32) (in all variants of the method according to the invention, which include step V32) and the removal of water) is carried out by heating the molded molding material mixture and / or the resulting uncured follow-up product and / or the green-resistant molded part and (preferably simultaneous) removal of water from the molded molding material mixture and / or from the resulting, not hardened secondary product and / or from the green-stable molded part.

• V32) das Behandeln des grünstandsfesten Formteils,
  • - durch Erhitzen des grünstandsfesten Formteils, vorzugsweise auf eine Temperatur im Bereich von 100 °C bis 300 °C, besonders bevorzugt im Bereich von 150 °C bis 250 °C und ganz besonders bevorzugt im Bereich von 180 °C bis 230 °C, und/oder (vorzugsweise „und“)
  • - durch Entfernen von Wasser aus der dem grünstandsfesten Formteil.

Also preferred is an embodiment of the method according to the invention specified above, preferably a method according to the invention (ii) (preferably a method according to the invention designated above or below as preferred), the molding material mixture as hardener component c) only comprising component c1), one or more biopolymers selected from the group of poly-D-glucosamines and which, in addition to and after step V31) defined above, comprises the step:

• V32) the treatment of the green-stable molded part,
  • by heating the molded part which is stable on green, preferably to a temperature in the range from 100 ° C. to 300 ° C., particularly preferably in the range from 150 ° C. to 250 ° C. and very particularly preferably in the range from 180 ° C. to 230 ° C., and / or (preferably "and")
  • - By removing water from the molded part that is green-proof.

In a further, particularly preferred embodiment of the process according to the invention, the molding material mixture comprises, as hardener component c), both component c1), one or more biopolymers selected from the group of poly-D-glucosamines, and additionally component c2), one or more Polyisocyanates. In this embodiment, molded parts with particularly advantageous properties can be produced, in particular molded parts with a particularly high moisture resistance or a particularly high water resistance and with a particularly high initial strength, a particularly high final strength and a particularly high cast resistance.

• - aromatischen Polyisocyanaten, vorzugsweise wasserverträglichen aromatischen Polyisocyanaten,
• - aliphatischen Polyisocyanaten, vorzugsweise den unten näher bezeichneten bevorzugten aliphatischen Polyisocyanaten und
• - deren Gemischen.

In the aforementioned, particularly preferred embodiment of the process according to the invention, in which the molding material mixture as hardener component c) comprises both component c1) and component c2), the polyisocyanates of component c2) are preferably selected from the group consisting of:

• aromatic polyisocyanates, preferably water-compatible aromatic polyisocyanates,
• - Aliphatic polyisocyanates, preferably the preferred aliphatic polyisocyanates described below and
• - their mixtures.

Aromatic polyisocyanates (as stated above) have the advantage that they can be crosslinked with the structural units of the formula I which contain hydroxyl groups in each case with the one or more aliphatic polymers and are therefore suitable for the production of moldings with high moisture resistance. However, the use of aromatic polyisocyanates is not particularly advantageous if the production of hardened molded parts in the foundry industry is important to work with as little emissions as possible and to produce as few odor and / or pollutants as possible, since aromatic polyisocyanates are used in such undesirable emissions .

In all variants of the process according to the invention in which component c2) is used in step V1), the polyisocyanates of component c2) therefore preferably comprise aliphatic polyisocyanates, particularly preferably the preferred aliphatic polyisocyanates described in more detail below. In these preferred variants of the process according to the invention (in which component c2) is used in step V1), the abovementioned aliphatic polyisocyanates or the preferred aliphatic polyisocyanates preferably make up a proportion of 75 75% by weight, particularly preferably of 90 90%. -% and very particularly preferably from ≥ 95 wt .-%, based on the total mass of one or more polyisocyanates used (or present) in the molding material mixture. In a particularly preferred variant of this embodiment of the process according to the invention, the polyisocyanates of component c2) comprise only aliphatic polyisocyanates, preferably only the preferred aliphatic polyisocyanates described below.

Aliphatic polyisocyanates have the advantage that they contribute even less to the occurrence of undesirable emissions of odors and / or pollutants and of smoke or fumes when carrying out the process according to the invention than, for example, aromatic (i.e. containing organic, aromatic rings) polyisocyanates.

In the particularly preferred embodiment of the process according to the invention, in which the molding material mixture as hardener component c) comprises both constituent c1) and additionally constituent c2), step V31), the precipitation of at least portions of the one or more, is preferably used to produce a green-resistant molded part several biopolymers.

If step V32) is carried out in this embodiment of the method according to the invention, this is carried out either with the molded molding material mixture and / or with the resulting uncured secondary product (as obtained after step V2)), or this is preferably, additionally after carrying out step V31), carried out with the molded part which is stable on the green. The removal of water in step V32) can then be carried out by one, by two or by all three of the measures mentioned above (freeze drying, vacuum drying, heating).

• - das Erhitzen der geformten Formstoffmischung und/oder des daraus entstandenen nicht gehärteten Folgeproduktes und/oder des grünstandsfesten Formteils, vorzugsweise des grünstandsfesten Formteils, vorzugsweise auf eine Temperatur im Bereich von 100 °C bis 300 °C, besonders bevorzugt im Bereich von 150 °C bis 250 °C und ganz besonders bevorzugt im Bereich von 180 °C bis 230 °C, und
• - das Entfernen von Wasser aus der geformten Formstoffmischung und/oder aus dem daraus entstandenen, nicht gehärteten Folgeprodukt und/oder aus dem grünstandsfesten Formteil, vorzugsweise aus dem grünstandsfesten Formteil;

In the particularly preferred embodiment of the method according to the invention, in which the molding material mixture as hardener component c) comprises both component c1) and component c2), step V33) is preferably carried out in addition to step V32) (and preferably simultaneously with this) . The crosslinking of hydroxyl groups and isocyanate groups in step V33) to produce the crosslinked molding preferably comprises:

• - The heating of the molded molding material mixture and / or the resulting non-hardened secondary product and / or the green part, preferably the green part, preferably to a temperature in the range from 100 ° C to 300 ° C, particularly preferably in the range from 150 ° C up to 250 ° C and very particularly preferably in the range from 180 ° C to 230 ° C, and
• - The removal of water from the molded molding material mixture and / or from the resulting, not hardened secondary product and / or from the green-proof molded part, preferably from the green-proof molded part;

The hardening in step V3) of the method according to the invention therefore also includes step V33) (as defined above) in this case in addition to step V32).

As mentioned above, a molded molding material mixture produced by the method according to the invention and / or a non-hardened secondary product resulting therefrom can also be converted to the hardened molded part or to the crosslinked (hardened) molded part, like a green-stable molded part produced by the method according to the invention. I.e. Step V32) can be carried out according to the method according to the invention after step V2) or after step V31). Conversely, however, it is not preferred to carry out step V31) after step V32), since a precipitation of at least portions of the one or more biopolymers in the molded molding material mixture and / or in the resulting uncured follow-up product (in step V31)) after it has been heated or after water has been removed from it or from it, this is generally not technically expedient or not possible.

In a variant of the method according to the invention, to carry out step V32) (and preferably additionally or simultaneously from step V33)), a shaped molding material mixture (produced in step V2) and / or a non-hardened secondary product resulting therefrom is generally heated together with the molding tool (for example a molding box or a shooting head), in a drying device, for example a drying oven, a belt dryer, a continuous dryer, a tunnel dryer or a drying belt, or also by passing a heated gas, preferably heated air, through the shaped molding material mixture to a temperature indicated above, and preferably - particularly preferably at the same time - removes water from the molded molding material mixture and / or from the resulting, non-hardened secondary product. In this process variant, a drying oven is preferably used as the drying device, particularly preferably a circulating air drying oven. The hardened molded part can then usually be removed from the mold (if present or still available).

In another variant of the method according to the invention, to carry out step V32) (and preferably additionally or simultaneously from step V33)), a green-stable molded part produced by the method according to the invention is heated, either together with the molding tool (for example a molding box or a shooting head) or preferably without the molding tool, in a drying device, for example a drying oven, a belt dryer, a continuous dryer, a tunnel dryer or a drying belt, to a temperature specified above, and preferably - and particularly preferably at the same time - removes water from the green-stable molded part. In this variant of the method, too, a drying oven is preferably used as the drying device, particularly preferably a circulating air drying oven.

The advantage of this last-mentioned method variant lies above all in the fact that the green part which is stable on the green is not in a mold and in particular not in a heatable mold to the hardened molded part (in particular to the crosslinked, hardened molded part), but instead (for example at room temperature) removed from the mold and separately in a suitable drying device (in particular by heating and removing water as described above) to the hardened molded part (in particular for crosslinked Molding) can be implemented. In this way, non-heatable molding tools such as cold box core shooters known per se can be used for molding the molding material mixture or the resulting, non-hardened secondary product and / or for producing the green-stable molded part, so that, for example, for carrying out this process variant according to the invention No time-consuming and costly retrofits to production sites equipped for cold box processes are necessary. However, since the implementation of this process variant is not limited to the implementation in non-heatable molds, it can be carried out at production sites equipped with different equipment, so that the further advantages of the process according to the invention can be used very flexibly in industry.

In general, the setting of the exact process parameters of the process according to the invention in step V32) and / or in step V33), for example the duration of the heating, the temperature of the drying oven or of the heated gas, the flow time with heated gas (ie the duration of the passage of the heated gas) Gas) and the pressure of the heated gas (if used) to a large extent depending on the properties of the molded part to be produced by curing, such as its size, its weight, its volume or its wall thickness. If necessary, the parameters suitable in the individual case can be determined by the skilled person in preliminary tests in a manner known per se.

• - die Formstoffmischung als Härterkomponente c) (mindestens) den Bestandteil c2), ein oder mehrere Polyisocyanate, vorzugsweise aliphatische Polyisocyanate, umfasst, und/oder
• - das Härten in Schritt V3) umfasst
  • V32) das Behandeln der geformten Formstoffmischung und/oder des daraus entstandenen, nicht gehärteten Folgeproduktes und/oder (bei Anwesenheit des Bestandteils c1) und vorheriger Durchführung des Schrittes V31)) des grünstandsfesten Formteils,
    • - durch Erhitzen der geformten Formstoffmischung und/oder des daraus entstandenen, nicht gehärteten Folgeproduktes und/oder des grünstandsfesten Formteils, vorzugsweise auf eine Temperatur im Bereich von 100 °C bis 300 °C, besonders bevorzugt im Bereich von 150 °C bis 250 °C und ganz besonders bevorzugt im Bereich von 180 °C bis 230 °C, und/oder (vorzugsweise „und“)
    • - durch Entfernen von Wasser aus der geformten Formstoffmischung und/oder aus dem daraus entstandenen, nicht gehärteten Folgeprodukt und/oder aus dem grünstandsfesten Formteil,
    und (zusätzlich zu Schritt V31) und/oder V32), vorzugsweise zusätzlich zu Schritt V32)) vorzugsweise
  • V33) das Vernetzen lassen von Hydroxygruppen des bzw. der aliphatischen Polymere der Formel I mit Isocyanat-Gruppen der Polyisocyanate, in der geformten Formstoffmischung und/oder in dem daraus entstandenen, nicht gehärteten Folgeprodukt und/oder in dem grünstandsfesten Formteil, so dass als gehärtetes Formteil ein vernetztes Formteil resultiert.

Also preferred is an inventive method specified above, preferably an inventive method (ii) (preferably an inventive method described above or below as preferred),
in which

• - The molding material mixture as hardener component c) comprises (at least) component c2), one or more polyisocyanates, preferably aliphatic polyisocyanates, and / or
• - The hardening in step V3) includes
  • V32) the treatment of the shaped molding material mixture and / or the resulting, not hardened secondary product and / or (in the presence of component c1) and prior execution of step V31)) of the green-stable molded part,
    • by heating the shaped molding material mixture and / or the resulting, not hardened secondary product and / or the green part which is resistant to green standing, preferably to a temperature in the range from 100 ° C. to 300 ° C., particularly preferably in the range from 150 ° C. to 250 ° C. and very particularly preferably in the range from 180 ° C. to 230 ° C., and / or (preferably “and”)
    • by removing water from the molded molding material mixture and / or from the non-hardened secondary product resulting therefrom and / or from the green part which is stable on greenery,
    and (in addition to step V31) and / or V32), preferably in addition to step V32)) preferably
  • V33) the crosslinking of hydroxyl groups of the aliphatic polymer (s) of the formula I with isocyanate groups of the polyisocyanates, in the molded molding material mixture and / or in the resultant uncured secondary product and / or in the green component which is stable on green, so that it is cured Molding results in a cross-linked molding.

• In dieser Ausgestaltung des erfindungsgemäßen Verfahrens, worin die Formstoffmischung als Härterkomponente c) nur den Bestandteil c2) (nicht aber den Bestandteil c1)) umfasst, umfassen die Polyisocyanate des Bestandteils c2) vorzugsweise einen Anteil von ≥ 75 Gew.-%, besonders bevorzugt von ≥ 90 Gew.-% und ganz besonders bevorzugt von ≥ 95 Gew.-% an aliphatischen Polyisocyanaten, vorzugsweise an (den oben angegebenen und unten näher definierten) erfindungsgemäß bevorzugt einzusetzenden aliphatischen Polyisocyanaten, bezogen auf die Gesamtmasse der in der Formstoffmischung eingesetzten (bzw. vorliegenden) ein oder mehreren Polyisocyanate des Bestandteils c2). In einer besonders bevorzugten Variante dieser Ausgestaltung des erfindungsgemäßen Verfahrens umfassen die Polyisocyanate des Bestandteils c2) nur aliphatische Polyisocyanate, vorzugsweise nur die unten näher bezeichneten bevorzugten aliphatischen Polyisocyanate, als Bestandteil c2). In dieser bevorzugten Ausgestaltung des erfindungsgemäßen Verfahrens (worin die Formstoffmischung als Härterkomponente c) nur den Bestandteil c2) umfasst) wird kein grünstandsfestes Formteils hergestellt.

In many cases, an embodiment of the preferred method according to the invention specified above is also preferred, the molding material mixture as hardener component c) only comprising hardener component c2), one or more polyisocyanates (ie in this embodiment, hardener component c) does not comprise component c1), one or more biopolymers selected from the group of poly-D-glucosamines):

• In this embodiment of the process according to the invention, in which the molding material mixture as hardener component c) comprises only component c2) (but not component c1)), the polyisocyanates of component c2) preferably comprise a proportion of 75 75% by weight, particularly preferably of ≥ 90% by weight and very particularly preferably of ≥ 95% by weight of aliphatic polyisocyanates, preferably of aliphatic polyisocyanates to be preferably used according to the invention (above and defined below), based on the total mass of the (or present) one or more polyisocyanates of component c2). In a particularly preferred variant of this embodiment of the process according to the invention, the polyisocyanates comprise of component c2) only aliphatic polyisocyanates, preferably only the preferred aliphatic polyisocyanates described in more detail below, as component c2). In this preferred embodiment of the process according to the invention (in which the molding material mixture comprises only component c2) as hardener component c), no molded part which is stable on green is produced.

In the preferred embodiment of the method according to the invention, in which the molding material mixture as hardener component c) comprises only component c2) (but not component c1)), step V32) and preferably additionally (and preferably simultaneously with step V32)) step V33) are carried out in each case carried out analogously or correspondingly as indicated above for the design of the process, in which the molding material mixture as hardener component c) comprises both component c1) and component c2). Step V32) is carried out in each case with the shaped molding material mixture (as obtained after step V2)) or with a resultant, non-hardened follow-up product (but not with a molded part which is green-proof).

For the particularly preferred embodiment of the process according to the invention, in which the molding material mixture as hardener component c) comprises both component c2), one or more polyisocyanates, and additionally component c1), one or more biopolymers selected from the group of poly-D-glucosamines, includes, see above.

• V1) Herstellen einer Formstoffmischung, umfassend die folgenden Bestandteile:
  1. a) mindestens einen Formgrundstoff,
  2. b) ein oder mehrere aliphatische Polymere jeweils umfassend Hydroxygruppen enthaltende Struktureinheiten der Formel I -CH₂-CH(OH)- (I),
  3. c) als Härterkomponente beide Bestandteile ausgewählt aus der Gruppe bestehend aus:
     • c1) ein oder mehrere Biopolymere ausgewählt aus der Gruppe der Poly-D-Glucosamine und
     • c2) ein oder mehrere Polyisocyanate, vorzugsweise aliphatische Polyisocyanate, als Vernetzungsmittel für Hydroxygruppen des bzw. der aliphatischen Polymere;
     und
  4. d) Wasser;
• V2) Formen der Formstoffmischung, und anschließend
• V3) Härten der geformten Formstoffmischung oder eines daraus entstandenen, nicht gehärteten Folgeproduktes, wobei das Härten in Schritt V3) umfasst
  • V31) das Ausfällen von zumindest Anteilen der ein oder mehreren Biopolymere, vorzugsweise durch Erhöhen des pH-Wertes der wässrigen Anteile der geformten Formstoffmischung, besonders bevorzugt durch Kontaktieren, vorzugsweise Begasen, mit einer alkalisch reagierenden gasförmigen Verbindung, ganz besonders bevorzugt durch Begasen mit einem gasförmigen Amin, so dass ein grünstandsfestes Formteil resultiert; und/oder (vorzugsweise „und“)
  • V32) das Behandeln der geformten Formstoffmischung und/oder des daraus entstandenen, nicht gehärteten Folgeproduktes und/oder des grünstandsfesten Formteils, vorzugsweise des grünstandsfesten Formteils (nach vorheriger Durchführung des Schrittes V31)),
    • - durch Erhitzen der geformten Formstoffmischung und/oder des daraus entstandenen, nicht gehärteten Folgeproduktes und/oder des grünstandsfesten Formteils (vorzugsweise des grünstandsfesten Formteils), vorzugsweise auf eine Temperatur im Bereich von 100 °C bis 300 °C, besonders bevorzugt im Bereich von 150 °C bis 250 °C und ganz besonders bevorzugt im Bereich von 180 °C bis 230 °C, und/oder (vorzugsweise „und“)
    • - durch Entfernen von Wasser aus der geformten Formstoffmischung und/oder aus dem daraus entstandenen, nicht gehärteten Folgeprodukt und/oder aus dem grünstandsfesten Formteil (vorzugsweise aus dem grünstandsfesten Formteil),
    und (zusätzlich zu Schritt V31) und/oder V32), vorzugsweise zusätzlich zu Schritt V32)) vorzugsweise
  • V33) das Vernetzen lassen von Hydroxygruppen des bzw. der aliphatischen Polymere der Formel I mit Isocyanat-Gruppen der Polyisocyanate in der geformten Formstoffmischung und/oder in dem daraus entstandenen, nicht gehärteten Folgeprodukt und/oder in dem grünstandsfesten Formteil (vorzugsweise in dem grünstandsfesten Formteil), so dass als gehärtetes Formteil ein vernetztes Formteil resultiert.

It is therefore preferred a method according to the invention specified above i) for producing a metallic casting and / or ii) for producing a hardened molded part selected from the group consisting of casting mold, core and feeder, for use in the casting of metallic castings, (preferably one above or hereinafter referred to as the preferred method according to the invention), with the following steps:

• V1) Preparation of a molding material mixture comprising the following constituents:
  1. a) at least one basic molding material,
  2. b) one or more aliphatic polymers each comprising structural units of the formula I containing hydroxyl groups -CH ₂ -CH (OH) - (I),
  3. c) as hardener component, both components selected from the group consisting of:
     • c1) one or more biopolymers selected from the group of poly-D-glucosamines and
     • c2) one or more polyisocyanates, preferably aliphatic polyisocyanates, as crosslinking agents for hydroxyl groups of the aliphatic polymer (s);
     and
  4. d) water;
• V2) shaping the molding material mixture, and then
• V3) hardening the shaped molding material mixture or a resultant, non-hardened secondary product, the hardening in step V3) comprising
  • V31) the precipitation of at least portions of the one or more biopolymers, preferably by increasing the pH of the aqueous portions of the molded molding material mixture, particularly preferably by contacting, preferably gassing, with an alkaline gaseous compound, very particularly preferably by gassing with a gaseous one Amine, so that a green-stable molded part results; and / or (preferably "and")
  • V32) the treatment of the shaped molding material mixture and / or the resulting, not hardened secondary product and / or the green part that is resistant to green standing, preferably the green part that is stable to green standing (after step V31 has been carried out beforehand)),
    • - by heating the shaped molding material mixture and / or the resulting, not hardened secondary product and / or the green-resistant molded part (preferably the green-fixed molded part), preferably to a temperature in the range from 100 ° C. to 300 ° C., particularly preferably in the range from 150 ° C to 250 ° C and very particularly preferably in the range from 180 ° C to 230 ° C, and / or (preferably "and")
    • by removing water from the molded molding material mixture and / or from the resulting, non-hardened secondary product and / or from the green-proof molded part (preferably from the green-proof molded part),
    and (in addition to step V31) and / or V32), preferably in addition to step V32)) preferably
  • V33) the crosslinking of hydroxyl groups of the aliphatic polymer (s) of the formula I with isocyanate groups of the polyisocyanates in the molded molding material mixture and / or in the resulting uncured secondary product and / or in the green-resistant molded part (preferably in the green-fixed molded part) ), so that a cross-linked molded part results as a hardened molded part.

It has been shown in our own experiments that the (crosslinked) hardened moldings produced (ie according to the variant, of the process according to the invention) prepared and crosslinked according to the particularly preferred variant of the process according to the invention specified above, and in which the molding material mixture comprises components c1) and c2) step V32) comprises heating and removing water and both steps V32) and V33) are carried out) a high initial strength, a particularly high final strength (after hardening or crosslinking) as well as a particularly high casting strength and a particularly high temperature resistance during the Have castings with iron or steel. Also noticeable is the advantageous smooth and clean surface structure of these (crosslinked) hardened molded parts produced according to the particularly preferred variant of the method according to the invention specified above. Furthermore, it was also possible to show that the (crosslinked) hardened moldings produced according to this particularly preferred variant of the process according to the invention given above have particularly good moisture resistance and water resistance, which makes them excellent for long storage over days or weeks even under difficult climatic conditions ( humid and warm climate) are suitable. In the case of metal casting, the (crosslinked) hardened moldings produced according to this particularly preferred variant of the process according to the invention indicated above also show only a low heat energy absorption, which results in a small formation of voids, which is only relatively far from the actual metal casting distant areas of the metal casting (such as in the feeder neck) occurs. This property also makes this variant of the method according to the invention particularly suitable for the production of feeders, in particular of insulating feeders. After metal casting has taken place, the (crosslinked) hardened molded parts produced in accordance with this variant of the process according to the invention are also distinguished by an extraordinarily advantageous unpacking behavior, since they largely disintegrate due to the heat released during metal casting and thus further processing of the correspondingly produced metal Simplify the casting considerably because only a few or, ideally, no further processing steps are required on the metal casting produced.

A particular advantage of the molded parts produced by the process according to the invention is their emission behavior, especially during metal casting and when unpacking metal castings which have been produced with the aid of these molded parts produced according to the invention: in metal casting with light metals or their alloys (for example in aluminum casting) as well as in iron or steel casting or when unpacking the correspondingly produced metal castings hardly any smoke or. Smoke formation, hardly any occurrence of unpleasant smells and / or hardly any emissions of substances which are potentially harmful to health are observed, as they occur regularly when using conventional organic foundry binders, especially those containing aromatics (such as those containing aromatic polyols and aromatic polyisocyanates in particular). This applies in particular to feeders produced using the method according to the invention. Insulating feeders produced by the method according to the invention (in particular according to its preferred variants) show hardly any undesirable emissions, even at the relatively low temperatures of the light metal casting. Exothermic feeders produced by the method according to the invention show hardly any undesirable emissions (such as smoke development) even during or after the combustion. Particularly low smoke or smoke formation, particularly low occurrence of unpleasant odors and / or particularly low emissions of substances which are potentially hazardous to health are observed if predominantly or exclusively aliphatic polyisocyanates are used as component c2) in the process according to the invention, preferably those designated as preferred in this text aliphatic polyisocyanates, and / or if at best small amounts and preferably no other aromatics-containing constituents are used in the process according to the invention.

• - herstellbar sind durch mindestens partielle Verseifung von Polyvinylacetat; und/oder
• - ausgewählt sind aus der Gruppe bestehend aus Polyvinylalkohole, Polyvinylacetate und deren Gemische; und/oder
• - ≥ 75 Gew.-%, vorzugsweise ≥ 90 Gew.-%, besonders bevorzugt ≥ 98 Gew.-%, der Gesamtmasse der in der Formstoffmischung, neben den als Bestandteil c1) eingesetzten ein oder mehreren Biopolymeren ausgewählt aus der Gruppe der Poly-D-Glucosamine, insgesamt eingesetzten, Hydroxygruppen umfassenden organischen Polymere ausmachen; und/oder
• - ein oder mehrere Polyvinylalkohole umfassen, wobei die Gesamtheit der eingesetzten Polyvinylalkohole vorzugsweise
  • - einen Hydrolysegrad von > 50 Mol-% (d.h. im Bereich von 50,1 Mol-% bis 100 Mol-%) aufweist, vorzugsweise bestimmt gemäß der Methode wie angegeben in Dokument DE 10 2007 026 166 A1 , Paragraphen [0029] bis [0034], und besonders bevorzugt einen Hydrolysegrad aufweist im Bereich von 70 Mol-% bis 100 Mol-%, ganz besonders bevorzugt im Bereich von 80 Mol-% bis 100 Mol-%, vorzugsweise bestimmt gemäß der Methode nach DIN EN ISO 15023-02 2017-02 Entwurf, Anhang D, und/oder
  • - eine dynamische Viskosität im Bereich von 0,1 bis 30 mPa · s aufweist, vorzugsweise im Bereich von 1,0 bis 15 mPa · s, besonders bevorzugt im Bereich von 2,0 bis 10 mPa · s, jeweils bestimmt an einer 4 %-igen (w/w) wässrigen Lösung der Gesamtheit der eingesetzten Polyvinylalkohole bei 20 °C nach DIN 53015:2001-02 ; und/oder
  • - ≥ 75 Gew.-%, vorzugsweise ≥ 90 Gew.-%, besonders bevorzugt ≥ 98 Gew.-%, der Gesamtmasse der in der Formstoffmischung insgesamt eingesetzten aliphatischen Polymere jeweils umfassend Hydroxygruppen enthaltende Struktureinheiten der Formel I ausmacht.

Also preferred is a method according to the invention specified above, preferably a method (ii) according to the invention (preferably a method according to the invention designated above or below as preferred),
the aliphatic polymers used each comprising structural units of the formula I containing hydroxyl groups

• - Can be produced by at least partial saponification of polyvinyl acetate; and or
• - are selected from the group consisting of polyvinyl alcohols, polyvinyl acetates and mixtures thereof; and or
• ≥ 75% by weight, preferably ≥ 90% by weight, particularly preferably ≥ 98% by weight, of the total mass of the molding material mixture, in addition to the one or more biopolymers used as component c1), selected from the group of poly- D-glucosamines, total organic polymers used which comprise hydroxyl groups; and or
• - comprise one or more polyvinyl alcohols, the entirety of the polyvinyl alcohols used preferably
  • - Has a degree of hydrolysis of> 50 mol% (ie in the range from 50.1 mol% to 100 mol%), preferably determined according to the method as indicated in the document DE 10 2007 026 166 A1 , Paragraphs [0029] to [0034], and particularly preferably has a degree of hydrolysis in the range from 70 mol% to 100 mol%, very particularly preferably in the range from 80 mol% to 100 mol%, preferably determined according to the method to DIN EN ISO 15023-02 2017-02 Draft, Appendix D, and / or
  • has a dynamic viscosity in the range from 0.1 to 30 mPas, preferably in the range from 1.0 to 15 mPas, particularly preferably in the range from 2.0 to 10 mPas, each determined at a 4% -igen (w / w) aqueous solution of all of the polyvinyl alcohols used at 20 ° C. DIN 53015: 2001-02 ; and or
  • ≥ 75% by weight, preferably 90 90% by weight, particularly preferably 98 98% by weight, of the total mass of the aliphatic polymers used overall in the molding material mixture in each case comprising structural units of the formula I containing hydroxyl groups.

In a preferred embodiment of the method according to the invention, the aliphatic polymers to be used are in each case fully (that is to say 100% by weight) structural units of the formula I containing hydroxyl groups as one or more polyvinyl alcohols.

The molding material mixture produced in step V1) of the process according to the invention comprises, as organic polymers comprising hydroxyl groups, constituents b), one or more aliphatic polymers each comprising structural units of formula I comprising hydroxyl groups, and (if present or used) c1), one or more biopolymers selected from the group of poly-D-glucosamines. In the process according to the invention, the constituents b) and (if present or used) c1) preferably make 95 95% by weight, particularly preferably 98 98% by weight, of the total mass in the molding material mixture overall in the molding material mixture prepared in step V1) used organic, comprising hydroxy groups, organic compounds. In a particularly preferred variant of the process according to the invention, constituents b) and (if present or used) c1) make up 100% by weight of the total mass of the organic hydroxyl groups comprising organic groups to be used in total in the molding material mixture in step V1) Connections out.

According to the invention, it is preferred to use the one or more aliphatic polymers each comprising hydroxyl group-containing structural units of the formula I (component b)) for producing or in the preparation of the molding material mixture in step V1) at least partially and preferably completely as an aqueous mixture comprising one or more aliphatic polymers each comprising hydroxyl-containing structural units of the formula I. This aqueous mixture preferably comprises the one or several aliphatic polymers in a total amount (concentration) in the range from 10% by weight to 40% by weight, particularly preferably in the range from 15% by weight to 35% by weight and very particularly preferably in the range from 20% by weight. -% to 30 wt .-%, based on the total mass of the aqueous mixture comprising one or more aliphatic polymers.

The one or more aliphatic polymers used, each comprising hydroxyl-containing structural units of the formula I, preferably the one or more polyvinyl alcohols, are in the said aqueous mixture in an amount of 90 90% by weight, preferably ≥ 95% by weight, based on the Total mass of one or more aliphatic polymers used, dissolved before.

It has been shown that the one or more aliphatic polymers specified above, in particular the one or more polyvinyl alcohols specified above as preferred, make a significant contribution to the advantageous properties of the hardened moldings produced according to the invention. In particular, the abovementioned one or more aliphatic polymers contribute to the good moisture resistance or water resistance, final strength and cast resistance of the hardened moldings produced according to the invention.

Apparently, the above-mentioned one or more aliphatic polymers, in particular the above-mentioned one or more polyvinyl alcohols, also make a significant contribution or are even the cause of the advantageous low emission properties of the hardened molded parts produced by the process according to the invention or its preferred variants. in particular for the low or very low emission of smoke or smoke and / or odors and / or pollutants during or after the metal casting and the low or very low emissions of odors and / or pollutants during manufacture or storage the hardened molded parts. This is probably due to the fact that the aliphatic polymers to be used according to the invention contain practically no or no aromatic constituents, which are frequently cited as the cause of harmful emissions.

The one or more aliphatic polymers to be used according to the invention are therefore preferably free from aromatics-containing constituents and / or other constituents which, under the conditions of the method according to the invention, cause significant amounts of smoke, smoke, odor and / or pollutant emissions.

For the reasons given above, the process according to the invention is preferably not carried out in the presence of aromatic-containing organic compounds or the molding material mixture produced in the process according to the invention is aromatic-free (ie contains the molding material mixture produced in the process according to the invention and also contains the constituents used for its production preferably no aromatic compounds containing organic compounds).

The molding material mixture prepared in step V1) preferably also does not contain any structural units of the formula I (constituent b)) which contain hydroxyl groups and which comprise the one or more aliphatic polymers and the one or more polyisocyanates, as crosslinking agents for hydroxyl groups of the or the aliphatic polymer active compound, selected from the group consisting of organotin compounds, organoaluminum compounds, dimethylcyclohexylamine, N-substituted pyrrolidones, N-substituted imidazoles, triazine derivatives, diazabicyclooctane or quaternary ammonium salts (as indicated in WO 2017/071695 A1 ).

• - das eine oder eines oder mehrere der mehreren (oder alle) Biopolymere ausgewählt aus der Gruppe der Poly-D-Glucosamine Chitosan umfassen, wobei das Chitosan vorzugsweise
  • - einen Deacetylierungsgrad von > 70 Mol-%, vorzugsweise von > 75 Mol-% und besonders bevorzugt von > 80 Mol-% aufweist, bestimmt mittels ¹H-NMR-Spektroskopie, und/oder
  • - eine dynamische Viskosität von > 500 mPa · s, vorzugsweise von > 600 mPa · s, besonders bevorzugt von ≥ 700 mPa · s aufweist, jeweils bestimmt an einer 1 %-igen (w/w) Lösung des Chitosans in 1 %-iger (w/w) Essigsäure bei 20 °C nach DIN 53015:2001-02 ,
  und/oder
• - das Verhältnis der Summe
  • - der Gesamtmasse der eingesetzten aliphatischen Polymere jeweils umfassend Hydroxygruppen enthaltende Struktureinheiten der Formel I und
  • - der Gesamtmasse an eingesetzten Biopolymeren ausgewählt aus der Gruppe der Poly-D-Glucosamine, zur
  • - Gesamtmasse an eingesetztem Formgrundstoff,

im Bereich von 0,2 : 100 bis 13 : 100 liegt, vorzugsweise im Bereich von 0,3 : 100 bis 10 : 100, besonders bevorzugt im Bereich von 0,5 : 100 bis 9 : 100.Also preferred is a method according to the invention specified above, preferably a method (ii) according to the invention (preferably a method according to the invention designated above or below as preferred),
in which

• - The one or one or more of the several (or all) biopolymers selected from the group of poly-D-glucosamines comprise chitosan, the chitosan preferably
  • has a degree of deacetylation of> 70 mol%, preferably of> 75 mol% and particularly preferably of> 80 mol%, determined by means of ¹ H-NMR spectroscopy, and / or
  • - Has a dynamic viscosity of> 500 mPa · s, preferably of> 600 mPa · s, particularly preferably of ≥ 700 mPa · s, each determined on a 1% (w / w) solution of the chitosan in 1% (w / w) acetic acid at 20 ° C after DIN 53015: 2001-02 ,
  and or
• - the ratio of the sum
  • - The total mass of the aliphatic polymers used, each comprising hydroxyl-containing structural units of the formula I and
  • - The total mass of biopolymers used selected from the group of poly-D-glucosamines
  • - total mass of molding material used,

is in the range from 0.2: 100 to 13: 100, preferably in the range from 0.3: 100 to 10: 100, particularly preferably in the range from 0.5: 100 to 9: 100.

In the embodiment of the process according to the invention specified above, the chitosan to be used preferably has a degree of deacetylation in the range from 65 mol% to 95 mol%, particularly preferably in the range from 70 mol% to 95 mol%, very particularly preferably in the range from 75 mole% to 95 mole% and most preferably in the range of 80 mole% to 95 mole%.

In the embodiment of the method according to the invention specified above, the chitosan to be used preferably has a dynamic viscosity in the range from 500 mPa · s to 1100 mPa · s, particularly preferably in the range from 600 mPa · s to 800 mPa · s, very particularly preferably in the range from 700 mPas to 800 mPas and most preferably in the range from 720 mPas to 770 mPas, each determined on a 1% (w / w) solution of the chitosan in 1% (w / w) acetic acid at 20 ° C after DIN 53015: 2001-02 (determined with the Höppler falling ball viscometer).

It has been shown that the above-mentioned preferred biopolymers selected from the group of poly-D-glucosamines, in particular the above-mentioned preferred chitosan, are particularly suitable for producing a molding material mixture in combination with the further constituents to be used according to the invention by the process according to the invention, which can first be converted in step V31) to a green part which is stable on green and then by further treatment in step V32) and preferably additionally in step V33) in a hardened molded part (or in a crosslinked, hardened molded part) which has the advantageous properties indicated above having. The use of biopolymers selected from the group of poly-D-glucosamines also opens up the possibility, at least in part, of using renewable raw materials to produce hardened molded parts for use in the foundry industry.

According to the invention, it is also preferred to use the one or more biopolymers selected from the group of the poly-D-glucosamines (component c1)), if present or used, at least partially and preferably completely, to prepare the molding material mixture in step V1) as an aqueous preparation comprising one or more biopolymers selected from the group of poly-D-glucosamines. The aqueous preparation to be used in the process according to the invention preferably comprises the one or more biopolymers selected from the group of poly-D-glucosamines in a total amount (concentration) in the range from 0.5% by weight to 10% by weight, particularly preferably in the Range from 1% by weight to 7.5% by weight and very particularly preferably in the range from 1.5% by weight to 5% by weight, based on the total mass of the aqueous preparation comprising one or more biopolymers. The aqueous preparation can additionally comprise an amount of one or more suitable acids which is suitable for partially or completely dissolving the one or more biopolymers. The aqueous preparation preferably comprises up to 5% by weight, particularly preferably up to 2.5% by weight, based on the total mass of the aqueous preparation, of one or more acids, selected from the acids which have a pKa value in the Range from 3 to 7, preferably in the range from 3.5 to 6.5 and preferably contain no aromatic organic compounds or radicals. Particularly preferably, said one or more acids are one or more organic acids, preferably one or more single-proton organic acids. The one or at least one of the said acids is very particularly preferably acetic acid.

The one or more biopolymers used are preferably selected from the group of the poly-D-glucosamines, preferably chitosan, in the said aqueous preparation in an amount of 90 90% by weight, preferably ≥ 95% by weight, dissolved before, based on the total mass of biopolymers used selected from the group of poly-D-glucosamines.

• - das eine bzw. eines oder mehrere oder alle der mehreren aliphatischen Polyisocyanate nichtionisch oder ionisch hydrophiliert sind, und/oder
• - das eine bzw. eines oder mehrere oder alle der mehreren aliphatischen Polyisocyanate eine Polyethergruppe oder eine Sulfonatgruppe umfasst bzw. umfassen, und/oder
• - das eine bzw. eines oder mehrere oder alle der mehreren aliphatischen Polyisocyanate eine Polyethergruppe und zudem eine Urethan- und/oder eine Allophanatgruppe umfasst bzw. umfassen, und/oder
• - das eine bzw. eines oder mehrere oder alle der mehreren aliphatischen Polyisocyanate eine oder mehrere 2,4,6-Trioxotriazingruppen umfasst bzw. umfassen sowie vorzugsweise eine Polyethergruppe oder eine Sulfonatgruppe, vorzugsweise eine Polyethergruppe umfasst bzw. umfassen, und/oder
• - das eine bzw. eines oder mehrere oder alle der mehreren aliphatischen Polyisocyanate eine oder mehrere 2,4,6-Trioxotriazingruppen sowie eine Polyethergruppe und zudem eine Urethan- und/oder eine Allophanatgruppe, vorzugsweise eine Urethangruppe, umfasst bzw. umfassen, und/oder
• - das eine bzw. eines oder mehrere oder alle der mehreren aliphatischen Polyisocyanate selbstemulgierende und/oder selbst-wasseremulgierbare aliphatische Polyisocyanate umfassen, und/oder
• - die eingesetzten ein oder mehreren aliphatischen Polyisocyanate ≥ 50 Gew.-%, vorzugsweise ≥ 75 Gew.-%, besonders bevorzugt ≥ 90 Gew.-% und ganz besonders bevorzugt ≥ 98 Gew.-%, der in der Formstoffmischung insgesamt eingesetzten ein oder mehreren Polyisocyanate ausmachen.

It is also preferred to use a process according to the invention specified above, preferably a process according to the invention (ii) (preferably a process according to the invention described above or below as preferred), the one or more polyisocyanates used as component c2) (if used or present) comprise aliphatic polyisocyanates (in the sense of aliphatic polyisocyanates to be used preferably in the process according to the invention),
in which

• - The one or one or more or all of the several aliphatic polyisocyanates are nonionically or ionically hydrophilized, and / or
• - The one or one or more or all of the several aliphatic polyisocyanates comprises or comprise a polyether group or a sulfonate group, and / or
• - The one or one or more or all of the several aliphatic polyisocyanates comprises or comprise a polyether group and also a urethane and / or an allophanate group, and / or
• - The one or one or more or all of the several aliphatic polyisocyanates comprises or comprise one or more 2,4,6-trioxotriazine groups and preferably comprises or comprises a polyether group or a sulfonate group, preferably a polyether group, and / or
• - The one or one or more or all of the several aliphatic polyisocyanates comprise one or more 2,4,6-trioxotriazine groups and a polyether group and also a urethane and / or an allophanate group, preferably a urethane group, and / or
• - The one or one or more or all of the several aliphatic polyisocyanates comprise self-emulsifying and / or self-water-emulsifiable aliphatic polyisocyanates, and / or
• the one or more aliphatic polyisocyanates used ≥ 50% by weight, preferably 75 75% by weight, particularly preferably 90 90% by weight and very particularly preferably 98 98% by weight, of the one or all used in the molding material mixture make up several polyisocyanates.

In a preferred embodiment of the preferred variant of the process according to the invention specified above, the one or more aliphatic polyisocyanates used make up 100% by weight of the total mass of the one or more polyisocyanates used overall in the molding material mixture.

The above-mentioned one or more aliphatic polyisocyanates which are preferably used according to the invention are preferably those with at least two free isocyanate groups, so that they are suitable for crosslinking with free hydroxyl groups of the aliphatic polymers each comprising structural units of the formula I which contain hydroxyl groups.

The above-mentioned one or more aliphatic polyisocyanates to be used according to the invention preferably include aliphatic and cycloaliphatic polyisocyanates. The aliphatic polyisocyanates to be preferably used according to the invention preferably do not contain any aromatic groups (i.e. are free from aromatics), for the reasons given above (avoidance of smoke, smoke, odor and / or pollutant emissions by the molded parts produced by the process according to the invention).

Preferably, the one or more aliphatic polyisocyanates to be used according to the invention are self-emulsifying or self-water-emulsifiable aliphatic polyisocyanates, as described, for example, in the book by Ulrich Meier-Westhues: "Polyurethanes - Varnishes, Adhesives and Sealants", Hanover : Vincentz Network 2007 (ISBN: 3-86630-896-5 or 978-3-86630-896-1), pp. 43-46.

• - nichtionisch hydrophylierten aliphatischen Polyisocyanaten vom Polyetherurethan-Typ, beispielsweise Bayhydur® 3100, Bayhydur® VP LS 2306, Desmodur® DA-L und Desmodur® DN
• - nichtionisch hydrophylierten aliphatischen Polyisocyanaten vom Polyetherallophanat-Typ, beispielsweise Bayhydur® 304 und Bayhydur® 305 und
• - ionisch hydrophilierten aliphatischen Polyisocyanaten vom Sulfonat-Typ, beispielsweise Bayhydur® XP 2487/1, Bayhydur® XP 2547, Bayhydur® XP 2570 und Bayhydur® XP 2655.

The above-mentioned one or more aliphatic polyisocyanates to be used according to the invention preferably comprise aliphatic polyisocyanates selected from the group consisting of:

• - Nonionically hydrophylated aliphatic polyisocyanates of the polyether urethane type, for example Bayhydur® 3100, Bayhydur® VP LS 2306, Desmodur® DA-L and Desmodur® DN
• - Nonionically hydrophylated aliphatic polyisocyanates of the polyether allophanate type, for example Bayhydur® 304 and Bayhydur® 305 and
• - Ionically hydrophilized aliphatic polyisocyanates of the sulfonate type, for example Bayhydur® XP 2487/1, Bayhydur® XP 2547, Bayhydur® XP 2570 and Bayhydur® XP 2655.

One or more aliphatic polyisocyanates to be used with particular preference in the process according to the invention are selected from the group consisting of nonionically hydrophylated aliphatic polyisocyanates of the polyether urethane type, for example Bayhydur® 3100, Bayhydur® VP LS 2306, Desmodur® DA-L and Desmodur® DN. A very particularly preferred aliphatic polyisocyanate to be used in the process according to the invention is Desmodur® DA-L (CAS RN 125252-47-3).

It has been shown that the preferred self-emulsifying or self-water-emulsifiable aliphatic polyisocyanates described above are extremely suitable under the conditions of the process according to the invention as crosslinking agents for the structural units of the formula I, each comprising hydroxyl groups and comprising hydroxyl groups, i.e. especially in an aqueous mixture or an aqueous binder system.

• b) ein oder mehrere aliphatische Polymere jeweils umfassend Hydroxygruppen enthaltende Struktureinheiten der Formel I -CH₂-CH(OH)- (I), und
• c2) ein oder mehrere Polyisocyanate als Vernetzungsmittel für Hydroxygruppen des bzw. der aliphatischen Polymere.

To the extent of the variants of the process according to the invention, in which the molding material mixture prepared in step V1) as hardener component c) (at least) component c2), one or more polyisocyanates, as crosslinking agent for hydroxyl groups of the aliphatic polymer (s) (only or also, preferably also , in addition to constituent c1)), a preferred process according to the invention, preferably a process (ii) according to the invention (preferably a process according to the invention described above or below as preferred) is preferred, the one or more aliphatic polymers each comprising structural units containing hydroxyl groups of the formula I (component b)) and the one or more polyisocyanates as crosslinking agents for hydroxyl groups of the aliphatic polymer (s) (component c2)) are provided or used as an aqueous mixture as the first binder system comprising:

• b) one or more aliphatic polymers each comprising structural units of the formula I containing hydroxyl groups -CH ₂ -CH (OH) - (I), and
• c2) one or more polyisocyanates as crosslinking agents for hydroxyl groups of the aliphatic polymer or polymers.

The aforementioned aqueous mixture to be used in the process according to the invention for producing the molding material mixture in step V31) preferably comprises, as the first binder system (hereinafter also referred to as “first binder system”), one or more structural units of the formula I containing hydroxyl groups, each comprising hydroxyl groups, in a total amount in the range from 5% by weight to 40% by weight, particularly preferably in the range from 7.5% by weight to 35% by weight and very particularly preferably in the range from 10% by weight to 30% by weight, based on the total mass of the first binder system.

The aforementioned first binder system to be used in the process according to the invention preferably comprises the one or more aliphatic polyisocyanates in a total amount in the range from 1% by weight to 20% by weight, particularly preferably in the range from 2.5% by weight to 15% by weight .-% and very particularly preferably in the range of 3 wt .-% to 10 wt .-%, based on the total mass of the first binder system.

In a preferred variant of the method according to the invention specified above, the weight fractions of constituents b), c2) supplement each other in the aqueous mixture as the first binder system. (each as defined above) and d) water to 100 wt .-%, ie to the total mass of the aqueous mixture as the first binder system.

Preferably, in the aqueous mixture as the first binder system, the aliphatic polymers used are each comprising structural units of the formula I comprising hydroxyl groups in a solution of 90 90% by weight, particularly preferably ≥ 95% by weight, based on the total mass of aliphatic polymers used .

In the variants of the process according to the invention specified above or below, in which the molding material mixture prepared in step V1) as hardener component c) (at least) component c2), one or more polyisocyanates, as crosslinking agents for hydroxyl groups of the aliphatic polymer (s) (only or also, preferably also, in addition to the component c1)), it is preferred if the components of the molding material mixture b) and c2) are brought into contact with one another only immediately before the production of the molding material mixture, preferably not earlier than one hour before the production of the molding material mixture . This prevents an undesirable premature start of a crosslinking reaction of the one or more polyisocyanates with hydroxyl groups of the one or more aliphatic polymers (e.g. in the absence of the basic molding material).

It has also been shown in our own experiments that a mixture of molding materials is obtained if components b), one or more aliphatic polymers, and c2) are particularly easy to process and shape, for example in shooting machines or molding boxes (such as core boxes) or more polyisocyanates, the molding material mixture used in step V1) in the amounts or proportions given above.

It has also been shown in our own experiments that the preferred variant of the process according to the invention, in which the one or more aliphatic polymers (component b)) and the one or more polyisocyanates (component c2)) are used in the form of an aqueous mixture as the first binder system , leads to a particularly homogeneous mixing of components b) and c2) with one another, so that, for example the crosslinking of hydroxyl groups of the aliphatic polymer (s) with isocyanate groups of the crosslinking agent takes place particularly completely in the presence of the basic molding material (step V33)) and thus the shaped molding material mixture (or a non-hardened secondary product resulting therefrom) is particularly completely and homogeneously integrated into one hardened molding or is converted into a crosslinked, hardened molding.

• b) ein oder mehrere aliphatische Polymere jeweils umfassend Hydroxygruppen enthaltende Struktureinheiten der Formel I -CH₂-CH(OH)- (I),
• c1) ein oder mehrere Biopolymere ausgewählt aus der Gruppe der Poly-D-Glucosamine und
• c2) ein oder mehrere Polyisocyanate, vorzugsweise ein oder mehrere aliphatische Polyisocyanate, als Vernetzungsmittel für Hydroxygruppen des bzw. der aliphatischen Polymere.

Within the scope of the preferred variants of the process according to the invention, in which the molding material mixture produced in step V1) as hardener component c) contains both component c1), one or more biopolymers selected from the group of poly-D-glucosamines, and component c2) or a plurality of polyisocyanates, as crosslinking agents for hydroxyl groups of the aliphatic polymer (s), an above-mentioned inventive method, preferably an inventive method (ii) (preferably an above-mentioned or hereinafter preferred inventive method) is preferred, the components b) , c1) and c2) are provided or used as an aqueous mixture as a second binder system comprising:

• b) one or more aliphatic polymers each comprising structural units of the formula I containing hydroxyl groups -CH ₂ -CH (OH) - (I),
• c1) one or more biopolymers selected from the group of poly-D-glucosamines and
• c2) one or more polyisocyanates, preferably one or more aliphatic polyisocyanates, as crosslinking agents for hydroxyl groups of the aliphatic polymer or polymers.

The aforementioned aqueous mixture to be used in the process according to the invention preferably comprises, as a second binder system (hereinafter also referred to as “second binder system”), the one or more aliphatic polymers, each comprising structural units of the formula I comprising hydroxyl groups, in a total amount in the range from 5% by weight to 30% by weight, particularly preferably in the range from 7.5% by weight to 25% by weight and very particularly preferably in the range from 10% by weight to 20% by weight, based on the total mass of the aqueous second Binder system.

The aforementioned aqueous mixture to be used in the process according to the invention preferably comprises, as a second binder system, the one or more biopolymers selected from the group of poly-D-glucosamines in a total amount in the range from 0.25% by weight to 5% by weight, particularly preferably in the range from 0.4% by weight to 3.5% by weight and very particularly preferably in the range from 0.5% by weight to 2.5% by weight, based on the total mass of the aqueous second binder system .

The aforementioned second binder system to be used in the process according to the invention preferably comprises the one or more aliphatic polyisocyanates in a total amount in the range from 1% by weight to 15% by weight, particularly preferably in the range from 2% by weight to 10% by weight. % and very particularly preferably in the range from 2.5% by weight to 7.5% by weight, based on the total mass of the aqueous second binder system.

In a preferred variant of the method according to the invention specified above, the weight fractions of the components b), c1), c2) (in each case as defined above) and d) water in the aqueous mixture as a second binder system add up to 100% by weight, i.e. to the total mass of the aqueous mixture as a second binder system.

Preferably, in the aqueous mixture as the second binder system, the aliphatic polymers used each have structural units of the formula I comprising hydroxyl groups at a concentration of ≥ 90% by weight, particularly preferably ≥ 95% by weight, in solution, based on the total mass of aliphatic polymers used .

It has been shown that the preferred variant of the method according to the invention, wherein the one or more aliphatic polymers (component b)), the one or more biopolymers selected from the group of poly-D-glucosamines (component c1)) and the one or several polyisocyanates (component c2)) is used in the form of a second binder system, leads to a particularly homogeneous mixing of its components with one another, so that, in particular, the crosslinking of hydroxyl groups of the aliphatic polymer or polymers with isocyanate groups of the crosslinking agent in the presence of the mold base material in particular takes place completely and thus the molded molding material mixture is particularly completely and homogeneously transferred into a hardened molded part or into a cross-linked, hardened molded part.

• - das Verhältnis
• - der Gesamtmasse an zur Herstellung der Formstoffmischung (in Schritt V1)) eingesetzten wässrigen Mischung oder wässrigen Mischungen, vorzugsweise ausgewählt aus der Gruppe bestehend aus der wässrigen Mischung umfassend ein oder mehrere aliphatische Polymere jeweils umfassend Hydroxygruppen enthaltende Struktureinheiten der Formel I, der wässrigen Zubereitung umfassend ein oder mehrere Biopolymere ausgewählt aus der Gruppe der Poly-D-Glucosamine, der wässrigen Mischung als erstes Bindemittelsystem und der wässrigen Mischung als zweites Bindemittelsystem; zur
• - Gesamtmasse an eingesetztem Formgrundstoff (in Schritt V1));

im Bereich von 1 :100 bis 50 : 100 liegt, vorzugsweise im Bereich von 1,5 : 100 bis 40 : 100, besonders bevorzugt im Bereich von 2 : 100 bis 35 : 100.Also preferred is a method according to the invention specified above, preferably a method (ii) according to the invention (preferably a method according to the invention designated above or below as preferred), wherein

• - The relationship
• - The total mass of aqueous mixture or aqueous mixtures used for producing the molding material mixture (in step V1)), preferably selected from the group consisting of the aqueous mixture comprising one or more aliphatic polymers, each comprising hydroxyl-containing structural units of the formula I, comprising the aqueous preparation one or more biopolymers selected from the group of the poly-D-glucosamines, the aqueous mixture as the first binder system and the aqueous mixture as the second binder system; to
• - total mass of molding raw material used (in step V1);

is in the range from 1: 100 to 50: 100, preferably in the range from 1.5: 100 to 40: 100, particularly preferably in the range from 2: 100 to 35: 100.

The setting of the above-mentioned (numerical) ratio of the sum of the total mass of the aqueous mixture or aqueous mixtures used to the total mass of mold base material is preferably carried out in such a way that one to a molded part, selected from the group consisting of mold, core and Feeder, shootable or tampable molding material mixture results. In this context, it has been shown that the ratio that is suitable in the individual case (with the concentrations of the aqueous mixtures used unchanged) depends, among other things, on the type of molding material used: the suitable numerical ratio given above is usually in the higher range (ie closer to the upper limit) of 50: 100 or 40: 100) in cases where a mold base material with a lower bulk density (preferably as quartz sand) is used, while the suitable numerical ratio given above tends to be in the lower range (ie closer to the lower limit of 1: 100 or 1.5: 100) is in cases in which a molding material with a higher bulk density (preferably quartz sand) is used.

• - das Verhältnis der Summe
  • - der Gesamtmasse der eingesetzten aliphatischen Polymere jeweils umfassend Hydroxygruppen enthaltende Struktureinheiten der Formel I und
  • - der Gesamtmasse an eingesetzten Biopolymeren ausgewählt aus der Gruppe der Poly-D-Glucosamine (sofern vorhanden bzw. eingesetzt),
  zur
  • - Gesamtmasse der als Vernetzungsmittel eingesetzten, vorzugsweise aliphatischen, Polyisocyanate (sofern vorhanden bzw. eingesetzt)
  im Bereich von 1 : 1 bis 10 : 1 liegt, vorzugsweise im Bereich von 1,5 : 1 bis 7,5 : 1 besonders bevorzugt im Bereich von 2:1 bis 5 : 1.

Also preferred is a method according to the invention specified above, preferably a method according to the invention (ii) (preferably a method according to the invention designated above or below as preferred) (preferably a method according to the invention, the molding material mixture as hardener component c) comprising both component c1), one or more Biopolymers selected from the group of poly-D-glucosamines, as well as component c2), which comprises one or more polyisocyanates),
in which

• - the ratio of the sum
  • - The total mass of the aliphatic polymers used, each comprising hydroxyl-containing structural units of the formula I and
  • - the total mass of biopolymers used selected from the group of poly-D-glucosamines (if present or used),
  to
  • - Total mass of the preferably aliphatic polyisocyanates used as crosslinking agents (if present or used)
  is in the range from 1: 1 to 10: 1, preferably in the range from 1.5: 1 to 7.5: 1, particularly preferably in the range from 2: 1 to 5: 1.

It has been shown that when carrying out the process according to the invention with the abovementioned biopolymers selected from the group of the poly-D-glucosamines (component c1)), the aliphatic polymers each comprising structural units of the formula I (component b)) and the as Crosslinking agents used, preferably aliphatic, polyisocyanates (component c2), in the amounts and ratios given above results in a green-stable molded part which is excellently suitable for further processing by the process according to the invention in the step of crosslinking hydroxyl groups of the or the aliphatic polymers with isocyanate Groups of the crosslinking agent (step V33)), so that a green-stable molded part can be converted particularly well (in step V32)) into a hardened molded part or (through step V32) and additionally step V33)) into a crosslinked, hardened molded part.

• - einen oder mehrere partikuläre feuerfeste Feststoffe, vorzugsweise ausgewählt aus der Gruppe bestehend aus
  • - Oxide, Silicate und Carbide, jeweils umfassend ein oder mehrere Elemente aus der Gruppe bestehend aus Si, AI, Zr, Ti, Mg, Fe und Ca,
  • - Mischoxide, Mischcarbide und Mischnitride, jeweils umfassend ein oder mehrere Elemente aus der Gruppe bestehend aus Si, AI, Zr, Ti, Mg, Fe und Ca, und
  • - Graphit
  und/oder
• - einen oder mehrere partikuläre Leichtfüllstoffe, vorzugsweise ausgewählt aus der Gruppe bestehend aus:
  • - Kern-Hülle-Partikel, vorzugsweise aufweisend einen Glaskern und eine feuerfeste Hülle, besonders bevorzugt mit einer Schüttdichte im Bereich von 470-500 g/L, vorzugsweise wie beschrieben im Dokument WO 2008/113765 A1 ;
  • - feuerfeste Kompositpartikel, vorzugsweise wie beschrieben in oder hergestellt gemäß Dokument WO 2017/093371 A1 ;
  • - Spheres, vorzugsweise Spheres aus Flugasche, wie z.B. Spheres „Fillite 106“ der Fa. Omya GmbH;
  • - Perlit, vorzugsweise geblähter Perlit wie insbesondere geblähter Perlit mit den Namen „Eurocell 140“, „Eurocell 145“, „Eurocell 150“ oder „Eurocell 300“ der Fa. RS Rohstoff-Sourcing GmbH;
  • - geschlossen-porige Mikro-Kugeln aus expandiertem Perlit, vorzugsweise wie beschrieben im Dokument WO 2017/174826 A1 ;
  • - Reisschalenasche, vorzugsweise wie beschrieben im Dokument WO 2013/014118 A2 ;
  • - Blähglas,
  • - Glashohlkugeln, und
  • - keramische Hohlkugeln, vorzugsweise Hohlkugelkorund.

Also preferred is a method according to the invention specified above, preferably a method (ii) according to the invention (preferably a method according to the invention designated above or below as preferred),
wherein the (at least one) basic molding material comprises:

• - One or more particulate refractory solids, preferably selected from the group consisting of
  • Oxides, silicates and carbides, each comprising one or more elements from the group consisting of Si, Al, Zr, Ti, Mg, Fe and Ca,
  • - Mixed oxides, mixed carbides and mixed nitrides, each comprising one or more elements from the group consisting of Si, Al, Zr, Ti, Mg, Fe and Ca, and
  • - graphite
  and or
• one or more particulate light fillers, preferably selected from the group consisting of:
  • - Core-shell particles, preferably having a glass core and a refractory shell, particularly preferably with a bulk density in the range of 470-500 g / L, preferably as described in the document WO 2008/113765 A1 ;
  • - Refractory composite particles, preferably as described in or produced according to the document WO 2017/093371 A1 ;
  • - Spheres, preferably spheres made from fly ash, such as Spheres “Fillite 106” from Omya GmbH;
  • - Perlite, preferably expanded perlite, such as expanded perlite with the names "Eurocell 140", "Eurocell 145", "Eurocell 150" or "Eurocell 300" from RS Rohstoff-Sourcing GmbH;
  • - Closed-pore micro-balls made of expanded pearlite, preferably as described in the document WO 2017/174826 A1 ;
  • - Rice bowl ash, preferably as described in the document WO 2013/014118 A2 ;
  • - expanded glass,
  • - hollow glass spheres, and
  • - Ceramic hollow spheres, preferably hollow spherical corundum.

The aforementioned one or more particulate refractory solids can be used individually or in combination with one another and thus form the basic molding material to be used in the process according to the invention. Likewise, the aforementioned one or more particulate light fillers can be used individually or in combination with one another and thus form the basic molding material to be used. Of course, the one or more particulate refractory solids in combination with the one or more particulate light fillers can also be used as the basic molding material and thus form the basic molding material to be used. Depending on the intended use of the method according to the invention, i.e. Depending on the hardened molded part to be produced, the person skilled in the art selects the suitable basic molding material. For example, only quartz sand can be selected as the basic molding material for producing a simple casting mold. Furthermore, a mixture of quartz sand with one or more particulate light fillers can be selected, for example, for the production of a feeder, or one or more particulate light fillers can also be selected for this purpose, preferably selected from the preferred group of light fillers defined above.

In addition to the preferred ingredients mentioned above, the mold base material to be used in the process according to the invention can also contain further, preferably particulate, constituents, preferably selected from the group consisting of elemental metals (for example aluminum), oxidizing agents and ignition agents. For example, in order to produce an exothermic feeder, the molding base material to be used may contain aluminum, iron oxide, oxidizing agents known per se for this purpose and ignition agents known per se in addition to the abovementioned constituents (selected from refractory solids and light fillers).

• V4) Kontaktieren des gehärteten Formteils, vorzugsweise wie erhalten nach Schritt V32) und vorzugsweise zusätzlich Schritt V33), mit einem Gießmetall zur Herstellung eines metallischen Gussstücks, wobei das Gießmetall vorzugsweise in Kontakt mit dem gehärteten Formteil erstarrt, wobei vorzugsweise
  • - das Gießmetall ausgewählt ist aus der Gruppe bestehend aus Aluminium, Magnesium, Zinn, Zink und deren Legierungen
  und/oder
  • - die Temperatur des Gießmetalls beim Abguss nicht höher ist als 900 °C;
  so dass ein metallisches Gussstück resultiert.

Also preferred is a method according to the invention specified above, preferably a method (i) according to the invention (preferably a method according to the invention designated above or below as preferred) for producing a metallic casting with the following additional step (preferably additionally carried out after performing step V32) and / or Step V33), particularly preferably additionally carried out after carrying out both steps V32) and V33)):

• V4) contacting the hardened molded part, preferably as obtained after step V32) and preferably additionally step V33), with a casting metal for producing a metallic casting, the casting metal preferably solidifying in contact with the hardened molded part, preferably
  • - The cast metal is selected from the group consisting of aluminum, magnesium, tin, zinc and their alloys
  and or
  • - The temperature of the cast metal during casting is not higher than 900 ° C;
  so that a metallic casting results.

In the preferred method according to the invention for producing a metallic casting described above, the casting metal is at least partially and preferably completely liquid when the hardened molded part or the crosslinked, hardened molded part comes into contact. Any castable metal or castable metal alloy, in particular light metals and their alloys, for example aluminum, magnesium, tin and zinc, is suitable as the casting metal; as well as iron and steel.

It has been shown in our own investigations that when contacting the hardened molded part produced according to the invention, in particular when contacting the crosslinked, hardened molded part produced according to the invention, with the cast metal - regardless of the nature of the cast metal - small amounts of soot or smoke or smoke are formed are and hardly, or ideally no, gaseous emissions that are potentially harmful to humans, for example through the decomposition of the crosslinked binder of the crosslinked, hardened molded part under the action of the heat of the liquid casting metal. This even applies to relatively low temperatures in the range from 600 ° C to 900 ° C, so that the aforementioned preferred process variant (i) is particularly suitable for the production of metallic castings, the cast metal being a light metal or a light metal alloy: it is Namely, it is known that at the relatively low temperatures prevailing in light metal casting (compared to the temperatures in iron or steel casting), conventional, currently frequently used, cold box binders are often only incompletely thermally decomposed, so that precisely in these cases - Both when casting metal and when unpacking the molds - there is a particularly strong formation of smoke, smoke or soot as well as a strong release of gaseous, aromatic-containing emissions, which are usually accompanied by unpleasant smells and are potentially harmful to people's health.

Such disadvantages exist when using hardened moldings produced by the process according to the invention or when carrying out the preferred process variant (i) according to the invention specified above, in particular the preferred process variants (i) described in this text, on the other hand to a much lesser extent or ideally not at all. Since feeders or feeder caps pose a particularly strong emission hazard in metal casting due to their position on the contact surface of casting molds with the ambient air, the preferred process variant (i) according to the invention indicated above is particularly effective if feeders or Feeder caps are produced (process variant (ii)) or used (process variant (i)), in particular if they have been crosslinked by the process according to the invention (in step V33)).

1. a) mindestens einen Formgrundstoff,
2. b) ein oder mehrere aliphatische Polymere jeweils umfassend Hydroxygruppen enthaltende Struktureinheiten der Formel I -CH₂-CH(OH)- (I), und
3. c) als Härterkomponente, ein oder beide Bestandteile ausgewählt aus der Gruppe bestehend aus:
   • c1) ein oder mehrere, vorzugsweise ausgefällte, Biopolymere ausgewählt aus der Gruppe der Poly-D-Glucosamine, vorzugsweise umfassend Chitosan und
   • c2) ein oder mehrere, vorzugsweise aliphatische, Polyisocyanate, wobei vorzugsweise die Hydroxygruppen der eingesetzten aliphatischen Polymere jeweils umfassend Hydroxygruppen enthaltende Struktureinheiten der Formel I (Bestandteil b)) mindestens teilweise vorliegen als durch Vernetzung mit Isocyanatgruppen der eingesetzten ein oder mehreren Polyisocyanate gehärtetes, vorzugsweise vernetztes, gehärtetes, Bindemittel.

The present invention further relates to a hardened molded part, preferably producible by a process according to the invention (ii) given above (preferably by a process according to the invention described above or below as preferred) selected from the group consisting of mold, core and feeder, for use in the casting of metallic castings, comprising the following components:

1. a) at least one basic molding material,
2. b) one or more aliphatic polymers each comprising structural units of the formula I containing hydroxyl groups -CH ₂ -CH (OH) - (I), and
3. c) as hardener component, one or both components selected from the group consisting of:
   • c1) one or more, preferably precipitated, biopolymers selected from the group of poly-D-glucosamines, preferably comprising chitosan and
   • c2) one or more, preferably aliphatic, polyisocyanates, preferably the hydroxyl groups of the aliphatic polymers used, each comprising at least partially structural units of the formula I (component b)) containing hydroxyl groups, as at least partially hardened, preferably crosslinked, by crosslinking with isocyanate groups of the one or more polyisocyanates used , hardened, binder.

With regard to preferred configurations of the hardened molded part according to the invention and possible combinations of one or more associated aspects with one another, the explanations given above for the method according to the invention apply accordingly, and vice versa.

Preferred as the above-mentioned hardened molded part according to the invention is a green molded part comprising, as hardener component c), component c1), one or more precipitated biopolymers selected from the group of poly-D-glucosamines, preferably comprising chitosan.

If the green-resistant molded part according to the invention additionally also comprises component c2), one or more, preferably aliphatic, polyisocyanates, these are one or more polyisocyanates and the one or more aliphatic polymers, each containing structural units of the formula I comprising hydroxyl groups, preferably uncrosslinked in the green-fixed molded part ( with each other).

Preferred as the above-mentioned hardened molding according to the invention is also a (crosslinked) hardened molding comprising, as curing component c), component c2), one or more, preferably aliphatic, polyisocyanates, the hydroxyl groups of the aliphatic polymers used each comprising structural units containing hydroxyl groups Formula I (component b)) is at least partially present as a hardened binder crosslinked by crosslinking with isocyanate groups of the one or more polyisocyanates used (component c2)).

If a hardened (or crosslinked, hardened) molded part according to the invention comprises a crosslinked binder by crosslinking hydroxy groups of the aliphatic polymers used, each comprising structural units of the formula I (component b)) containing isocyanate groups of the one or more polyisocyanates used (component c2)) For the purposes of the present invention, it is assumed that in the molded part according to the invention the hydroxyl groups of the crosslinked or crosslinking aliphatic polymer are no longer freely available (at least predominantly) but (at least predominantly) after the crosslinking by the isocyanate groups of the one or more polyisocyanates used ) are involved in the formation of urethane groups with the isocyanate groups.

The present invention also relates to a hardened molded part selected from the group consisting of casting mold, core and feeder, produced or producible by a method according to the invention specified above, preferably by a method (ii) according to the invention (or a preferred method according to the invention described in this text).

With regard to preferred configurations of the hardened molding produced or producible according to the invention and possible combinations of one or more associated aspects with one another, the explanations given above for the method according to the invention and for the hardened molding according to the invention apply accordingly, and vice versa.

• - der Gesamtmasse des im Formteil vorliegenden gehärteten Bindemittels zur
• - Gesamtmasse des im Formteil vorliegenden Formgrundstoffes

im Bereich von 0,1 : 100 bis 10 : 100, vorzugsweise im Bereich von 0,5 : 100 bis 7 : 100 und besonders bevorzugt im Bereich von 0,6 : 100 bis 6 : 100, liegt.A previously specified (crosslinked) hardened molded part according to the invention (or a corresponding preferred crosslinked, hardened molded part according to the invention described in this text or a crosslinked, hardened molded part which can be produced by the above described method according to the invention) is preferred, the ratio

• - The total mass of the hardened binder present in the molded part
• - Total mass of the basic molding material present in the molded part

is in the range from 0.1: 100 to 10: 100, preferably in the range from 0.5: 100 to 7: 100 and particularly preferably in the range from 0.6: 100 to 6: 100.

1. a) mindestens einen Formgrundstoff,
2. b) ein oder mehrere aliphatische Polymere jeweils umfassend Hydroxygruppen enthaltende Struktureinheiten der Formel I -CH₂-CH(OH)- (I),
3. c) als Härterkomponente, ein oder beide Bestandteile ausgewählt aus der Gruppe bestehend aus:
   • c1) ein oder mehrere Biopolymere ausgewählt aus der Gruppe der Poly-D-Glucosamine, vorzugsweise Chitosan, und
   • c2) ein oder mehrere, vorzugsweise aliphatische, Polyisocyanate, als Vernetzungsmittel für Hydroxygruppen des bzw. der aliphatischen Polymere;
   und
4. d) Wasser.

The present invention also relates to a molding material mixture, preferably selected for the production of a hardened molded part (including a green-proof molded part, if component c1) is present as the hardener component and / or a crosslinked, hardened molded part, if component c2) is present as the hardener component) from the group consisting of mold, core and feeder, for use in casting metallic castings, comprising the following components:

1. a) at least one basic molding material,
2. b) one or more aliphatic polymers each comprising structural units of the formula I containing hydroxyl groups -CH ₂ -CH (OH) - (I),
3. c) as hardener component, one or both components selected from the group consisting of:
   • c1) one or more biopolymers selected from the group of poly-D-glucosamines, preferably chitosan, and
   • c2) one or more, preferably aliphatic, polyisocyanates as crosslinking agents for hydroxyl groups of the aliphatic polymer or polymers;
   and
4. d) water.

In a particularly preferred variant of the above-mentioned molding material mixture according to the invention, this comprises, as hardener component c), component c1), one or more biopolymers selected from the group of poly-D-glucosamines, preferably chitosan, and additionally component c2), one or more, preferably aliphatic, polyisocyanates, as crosslinking agents for hydroxyl groups of the aliphatic polymer or polymers.

In a preferred variant of the above-mentioned molding material mixture according to the invention, this comprises, as hardener component c), only component c1), one or more biopolymers selected from the group of poly-D-glucosamines, preferably chitosan, but not component c2), one or more, preferably aliphatic, polyisocyanates, as crosslinking agents for hydroxyl groups of the aliphatic polymer or polymers.

In another preferred variant of the above-mentioned molding material mixture according to the invention, this comprises, as hardener component c), only component c2), one or more aliphatic polyisocyanates (preferably one or more aliphatic polyisocyanates to be used in the present text as preferred according to the invention) as crosslinking agents for hydroxyl groups aliphatic polymers, but not component c1), one or more biopolymers selected from the group of poly-D-glucosamines, preferably chitosan.

With regard to preferred configurations of the molding material mixture according to the invention and possible combinations of one or more associated aspects with one another, the explanations given above for the method according to the invention, the hardened molded part according to the invention and the hardened molded part produced or producible according to the invention apply accordingly, and vice versa.

The above-mentioned molding material mixture according to the invention (or a molding material mixture according to the invention mentioned above, referred to in this text as preferred) is suitable for use in the method according to the invention specified above and is intended therefor.

The present invention also relates to the use of an aliphatic polymer crosslinked by one or more aliphatic polyisocyanates comprising structural units of the formula I containing hydroxyl groups -CH ₂ -CH (OH) - (I), preferably of a crosslinked polyvinyl alcohol, as a binder of a hardened molded part selected from the group consisting of mold, core and feeder, for use in the casting of metallic castings.

With regard to preferred embodiments of the use according to the invention and possible combinations of one or more associated aspects with one another, the statements given above for the method according to the invention, the hardened molded part according to the invention, the hardened molded part produced or producible according to the invention and for the molding material mixture according to the invention apply accordingly, and vice versa.

The present invention also relates to the use of biopolymers selected from the group of poly-D-glucosamines, preferably chitosan, as binders or binder components for producing a hardened molded part, preferably a green-shaped molded part, selected from the group consisting of a mold, core and Feeder, in the foundry industry.

With regard to preferred configurations of the use of biopolymers according to the invention and possible combinations of one or more associated aspects with one another, the same applies to the method according to the invention, the hardened molded part according to the invention, the hardened molded part produced or producible according to the invention, the molding material mixture according to the invention and the use according to the invention of one or more aliphatic polyisocyanates crosslinked aliphatic polymer in accordance with the explanations given above, and vice versa.

Examples:

The examples given below are intended to describe and explain the invention in more detail without restricting its scope.

Unless otherwise stated, the tests were carried out under laboratory conditions (normal pressure, temperature 20 ° C, humidity 50%).

Example 1: Production of molding material mixtures

The constituents given in Table 1 below and described in more detail under Table 1 were used to produce mixtures of molding materials.

The molding material mixtures “F-Cold-Box” and “F-water glass” are comparative molding material mixtures not according to the invention or not to be used according to the invention. The molding material mixtures and “F-V6” and “F-E6 +” are molding material mixtures according to the invention or to be used according to the invention. Table 1: Components of molding material mixtures component Molding material mixture F cold box F water glass F-V6 F-E6 + Quartz sand BO42 [parts by weight] 100 100 100 100 Aqueous PVAL mixture [parts by weight] 0 0 3.6 3,428 Aliphatic polyisocyanate [parts by weight] 0 0 0 0.286 Aqueous preparation of chitosan [parts by weight] 0 0 2.4 2,286 Cold-box activator 6324 [parts by weight] 1.2 0 0 0 Cold box gas resin 7241 [parts by weight] 1.2 0 0 0 Soda water glass binder 48/50 [parts by weight] 0 1.5 0 0

Quartz sand BO 42 (CAS No. 014808-60-7) from Bodensteiner Sandwerk GmbH & Co. KG was used as the basic molding material.

A 25% by weight solution of polyvinyl alcohol (> 93% polyvinyl alcohol) with a degree of hydrolysis of approx. 88 mol% and a dynamic viscosity in the range from 3.5 to 4.5 mPa · s was used as the aqueous PVAL mixture (measured as a 4% by weight aqueous solution at 20 ° C. according to DIN 53015), methanol content: 3% by weight; CAS RN 25213-24-5 (Kuraray Europe GmbH).

The non-ionically hydrophilized polyisocyanate "Desmodur® DA-L" (Covestro AG) of the polyether urethane type (CAS RN 125252-47-3) was used as the aliphatic polyisocyanate.

A 2.5% by weight solution (based on the total mass of the solution) of chitosan 85/1000 (with a degree of deacetylation of 85 mol% and one%) was used as the aqueous preparation of chitosan dynamic viscosity of 1000 mPas according to manufacturer's information: Heppe Medical Chitosan GmbH) in a 1% by weight aqueous acetic acid solution (based on the total mass of the solution).

The cold box activator 6324 used was a polyisocyanate (activator 6324 from Hüttenes-Albertus Chemische Werke GmbH) which is customary for the production of cold box binders (polyurethane resin based on benzyl ether).

A phenolic resin (gas resin 7241 from Hüttenes-Albertus Chemische Werke GmbH), which is customary for the production of cold box binders (polyurethane resin based on benzyl ether), was used as the cold box gas resin 7241.

An aqueous solution of a standard water glass binder with a water glass content (sodium silicate content) in the range from 35% by weight to 50% by weight and a pH at 20 ° C. in the range from 11 was used as the sodium water glass binder 48/50 to 12 (CAS RN 1344-09-8).

• Formstoffmischung F-Cold-Box: die in Tabelle 1 genannten Bestandteile wurden in einem elektrischen Mischer (Bosch Profi 67) unter Rühren solange miteinander vermischt, bis eine homogene Formstoffmischung entstanden war. Die Formstoffmischung Cold-Box ist eine nicht nach dem erfindungsgemäßen Verfahren hergestellte bzw. nicht in einem solchen Verfahren einzusetzende Formstoffmischung, für Vergleichszwecke.
• Formstoffmischung F-Wasserglas: die in Tabelle 1 genannten Bestandteile wurden in einem elektrischen Mischer (Bosch Profi 67) unter Rühren solange miteinander vermischt, bis eine homogene Formstoffmischung entstanden war. Die Formstoffmischung F-Wasserglas ist eine nicht nach dem erfindungsgemäßen Verfahren hergestellte bzw. nicht in einem solchen Verfahren einzusetzende Formstoffmischung, für Vergleichszwecke.
• Formstoffmischung F-V6: die in Tabelle 1 genannten Bestandteile „wässrige PVAL-Mischung“ und „wässrige Zubereitung von Chitosan“ wurden in den in Tabelle 1 angegebenen Mengen in einem Becherglas miteinander zu einer Bindemittel-Vormischung vermischt. Anschließend wurde der Quarzsand in einem elektrischen Mischer (Bosch Profi 67) vorgelegt und es wurde dann unter Rühren die Bindemittel-Vormischung hinzugegeben und mit dem Quarzsand vermischt. Es wurde solange weiter gerührt, bis eine homogene Formstoffmischung entstanden war. Die Formstoffmischung F-V6 ist eine ist eine nach dem erfindungsgemäßen Verfahren hergestellte bzw. in einem solchen Verfahren einzusetzende Formstoffmischung.
• Formstoffmischung F-E6+: die in Tabelle 1 genannten Bestandteile „wässrige PVAL-Mischung“ und „wässrige Zubereitung von Chitosan“ wurden in den in Tabelle 1 angegebenen Mengen in einem Becherglas miteinander zu einer Bindemittel-Vormischung vermischt. Kurz vor der Herstellung der Formstoffmischung F-E6+ wurde zu der entstandenen Bindemittel-Vormischung die in Tabelle 1 angegebene Menge an aliphatischem Polyisocyanat hinzugegeben und mit der Bindemittel-Vormischung durch Vermischen miteinander (Rührmotor mit Flügelrührer) zu einem „zweiten Bindemittel-System“ (im Sinne der vorliegenden Erfindung) vereinigt. Anschließend wurde der Quarzsand in einem elektrischen Mischer (Bosch Profi 67) vorgelegt und es wurde dann unter Rühren das entstandene zweite Bindemittelsystem hinzugegeben und mit dem Quarzsand durch Vermischen vereinigt. Es wurde solange weiter gerührt, bis eine homogene Formstoffmischung entstanden war. Die Formstoffmischung F-E6+ ist eine nach dem erfindungsgemäßen Verfahren hergestellte bzw. in einem solchen Verfahren einzusetzende Formstoffmischung.

The molding material mixtures were produced as follows:

• Molding material mixture F-Cold-Box: The components listed in Table 1 were mixed in an electric mixer (Bosch Profi 67) with stirring until a homogeneous molding material mixture was obtained. The cold box molding material mixture is a molding material mixture which is not produced by the process according to the invention or is not to be used in such a process, for comparison purposes.
• F-water glass molding material mixture: The components listed in Table 1 were mixed in an electric mixer (Bosch Profi 67) with stirring until a homogeneous molding material mixture was obtained. The molding material mixture F-water glass is a molding material mixture which is not produced by the process according to the invention or which is not to be used in such a process, for comparison purposes.
• Molding material mixture F-V6: the components "aqueous PVAL mixture" and "aqueous preparation of chitosan" listed in Table 1 were mixed together in the amounts specified in Table 1 in a beaker to form a binder premix. The quartz sand was then placed in an electric mixer (Bosch Profi 67) and the binder premix was then added with stirring and mixed with the quartz sand. The stirring was continued until a homogeneous mixture of molding materials was obtained. The molding material mixture F-V6 is a molding material mixture produced by the process according to the invention or to be used in such a process.
• Molding material mixture F-E6 +: the components "aqueous PVAL mixture" and "aqueous preparation of chitosan" listed in Table 1 were mixed together in the amounts specified in Table 1 in a beaker to form a binder premix. Shortly before the production of the molding material mixture F-E6 +, the amount of aliphatic polyisocyanate specified in Table 1 was added to the resulting binder premix and mixed with the binder premix by mixing them together (stirrer motor with paddle stirrer) to form a “second binder system” (im Sense of the present invention). The quartz sand was then placed in an electric mixer (Bosch Profi 67) and the second binder system formed was then added with stirring and combined with the quartz sand by mixing. The stirring was continued until a homogeneous mixture of molding materials was obtained. The molding material mixture F-E6 + is a molding material mixture produced by the process according to the invention or to be used in such a process.

Example 2: Production of standard bending bars as model molded parts

From the molding material mixtures F-Cold-Box, F-water glass, F-V6 and F-E6 + specified in Example 1, standard bending bars (representative of a hardened molded part for use in casting metallic castings) were used for test purposes in a manner known to the person skilled in the art Rams manufactured (dimensions: 172 x 23 x 23 mm), in accordance with or analogous to the regulation in leaflet P73 (February 1996 edition) of the Association of German Foundry Professionals (hereinafter referred to as "VDG leaflet P73"), No. 4.1.

• Biegeriegel B-Cold-Box: Die Formstoffmischung F-Cold-Box (s. Beispiel 1) wurde in einer Biegestab-Rammbüchse wie oben beschrieben durch Rammen geformt. Anschließend wurde die geformte Formstoffmischung nach dem Cold-Box-Verfahren durch Hindurchleiten von (unter den Verfahrensbedingungen) gasförmigem N,N-Dimethylpropylamin (ca. 1 ml flüssig, 15 s) entsprechend der Vorschrift im VDG Merkblatt P73, Nr. 4.3, Verfahren A, gehärtet.
• Biegeriegel B-Wasserglas: Die Formstoffmischung F-Wasserglas wurde in einer Biegestab-Rammbüchse wie oben beschrieben durch Rammen geformt. Anschließend wurde durch die geformte Formstoffmischung (in der Biegestab-Rammbüchse) gasförmiges CO₂ hindurchgeleitet. Der nach CO₂-Begasung grünstandsfeste Biegeriegel wurde aus der Form entnommen (entformt) und durch Trocknen im Trockenofen für 20 min bei 210 °C und Entfernen von Wasser durch Umluft-Entlüftung des Trockenofens gehärtet (Standard-Biegeriegel, hier: Biegeriegel B-Wasserglas).
• Biegeriegel B-V6 und B-E6+: die Formstoffmischungen F-V6 und F-E6+ (Herstellung siehe Beispiel 1) wurden jeweils in einer Biegestab-Rammbüchse wie oben beschrieben durch Rammen geformt. Anschließend wurde durch die geformten Formstoffmischungen (unter den Verfahrensbedingungen) gasförmiges N,N-Dimethylpropylamin (entsprechend ca. 1 ml flüssig, 15 s) hindurchgeleitet (Begasung in der Biegestab-Rammbüchse), wodurch jeweils ein grünstandsfester Standard-Biegeriegel (d.h. modellhaftes, gehärtetes - hier: grünstandsfestes - Formteil) resultierte. Diese grünstandsfesten Standard-Biegeriegel wurden dann aus der Rammbüchse entnommen und jeweils im Trockenofen für 20 min bei 210 °C und Entfernen von Wasser durch Umluft-Entlüftung des Trockenofens zum gehärteten Formteil (Standard-Biegeriegel, hier: Biegeriegel B-V6) bzw. zum gehärteten Formteil mit Vernetzungsschritt (Biegeriegel B-E6+) verarbeitet.

The bending bars described above were hardened as indicated below (the processes for hardening the molding material mixtures “F-Cold-Box” and “F-water glass” as indicated below correspond to processes known from the prior art):

• Bending bar B-Cold-Box: The molding material mixture F-Cold-Box (see Example 1) was shaped in a bending rod ram as described above by ramming. The molded molding material mixture was then subjected to the cold box process by passing gaseous N, N-dimethylpropylamine (approx. 1 ml liquid, 15 s) (under the process conditions) in accordance with the instructions in VDG leaflet P73, No. 4.3, process A , hardened.
• Bending bar B-water glass: The molding material mixture F-water glass was formed by ramming in a bending rod ram as described above. Gaseous CO _{2 was then} passed through the molded molding material mixture (in the bending rod ram). The bending bar, which is green-stable after CO ₂ fumigation, was removed from the mold (demoulded) and hardened by drying in a drying oven for 20 min at 210 ° C and removal of water by venting the drying oven by circulating air (standard bending bar, here: bending bar B water glass ).
• Bending bars B-V6 and B-E6 +: the molding material mixtures F-V6 and F-E6 + (production see Example 1) were each formed by ramming in a bending rod ram as described above. Subsequently, gaseous N, N-dimethylpropylamine (corresponding to approx. 1 ml liquid, 15 s) was passed through the molded molding material mixtures (under the process conditions) (gassing in the bending rod ram sleeve), whereby a green-stable standard bending bar (ie modeled, hardened) - here: green stable - molded part) resulted. These green-stable standard bending bars were then removed from the ram and each in the drying oven for 20 min at 210 ° C and removing water by venting the drying oven to the hardened molded part (standard bending bar, here: bending bar B-V6) or hardened molded part with crosslinking step (bending bar B-E6 +) processed.

Example 3: Determination of the final strengths of standard bending bars

The final strengths of the standard bending bars produced in Example 2 above were tested: the final strength of the standard bending bar B-Cold-Box was checked 24 hours after its manufacture. The final strengths of the standard bending bars B-water glass, B-V6 and B-E6 + were tested for this 30 minutes after their manufacture (drying). All standard bending bars were stored under laboratory conditions. The final strengths were determined in triplicate, as described in VDG Leaflet P73, No. 5.2, with a Georg Fischer type PFG strength tester with low-pressure manometer (with motor drive).

The bending strengths (final strengths) of the standard bending bars given below in Table 2 were determined in this way: Table 2: final strengths of standard bending bars Bending bar: B cold box B water glass B-V6 B-E6 + Bending strength [N / cm2] 720 750 530 620

It can be seen from the values given in Table 2 that the hardened molded parts (standard bending bars) B-V6 and B-E6 + produced by the process according to the invention have lower final strengths than conventional cold box or water glass-bonded molded parts, but that the final strengths of the hardened moldings produced by the process according to the invention are completely sufficient in practice. The standard bending bar B-E6 + (produced with the cross-linking step) had a higher (near the corresponding value for a cold box-bound bending bar) for the ultimate strength than the standard bending bar B-V6 (produced without the cross-linking step).

Example 4: Determination of the strength of standard bending bars after aging

Standard bending bars B-water glass and B-E6 + produced as in Example 2 above were subjected to a storage test starting 24 hours after their manufacture (corresponds to aging time "0"). For this purpose, corresponding bending bars were stored for 60 h in a climatic cabinet at 40 ° C. and 90% relative atmospheric humidity and tested for their (remaining) bending strengths at the time intervals specified in Table 3, as indicated in Example 3. The respectively measured values of these bending strengths are given in Table 3 below: Table 3: Flexural strength after aging in a climatic cabinet for 60 h Bending bar: B water glass B-E6 + Outsourcing period Bending strengths [N / cm ² ] 0 750 620 8 h 750 260 12 h 480 290 24 hours 120 290 36 h 150 270 48 h 110 260 60 h 50 270

It can be seen from the values given in Table 3 that the hardened molded part (standard bending bar) B-E6 + produced by the process according to the invention shows a drop in strength after 8 hours under the storage conditions. After that, its strength remains almost constant over the rest of the storage period and is sufficient for practical purposes. In contrast, a significant drop in strength after 24 hours of storage can be observed with the water-glass-bound bending bar B-water glass, which continues until the end of the storage period until it becomes unusable.

The hardened molded part produced by the method according to the invention (standard bending bar, produced using the crosslinking step) B-E6 + is therefore significantly better suited for storage even under difficult climatic conditions (elevated temperature and air humidity) than a conventional, water glass-bound molded part.

Example 5: Determination of the water resistance of standard bending bars

Standard bending bars produced as in Example 2 above were placed on shelves so that only their ends rested (contact area approx. 1/10 of the total area of the underside of the standard bending bars). The shelves with the standard bending bars on top were placed in a water-filled container so that the undersides of the standard bending bars rested completely on the water surface and could absorb water through the capillary forces. The water resistance of the standard bending bars was then assessed visually over a period given in Table 4 below.

The results of this experiment are shown in Table 4 below. Table 4: Water resistance of standard bending bars Test duration Bending bar (observation) B cold box B-V6 B-E6 + 0 intact intact intact 3 s intact Upper side shows moisture intact 37 s intact Completely moisturized intact 82 s intact Burglary in the middle intact 351 s intact Breakthrough in the middle intact

It can be seen from the observations given in Table 4 that the standard bending bar bound with cold box binder was still completely water-resistant even after the longest exposure to water, as shown in Table 4. The hardened bending bar B-V6 produced by the method according to the invention (produced without a crosslinking step) took up water after a short time and broke after some time. The bending bar B-E6 + produced according to the invention had a higher water resistance than the hardened (not cross-linked) bending bar B-V6.

Example 6: Behavior of standard bending bars when casting iron

Standard bending bars B-Cold-Box (comparison), B-V6 (produced according to the method according to the invention) and B-E6 + (manufactured according to the method according to the invention) produced in Example 2 above were mixed with a conventional alcohol size (Koalid 4087 from Hüttenes- Albertus GmbH) finished in a manner known per se (conditions: run-down time 17.3 s; immersion time 7 s; drying 110 ° C for 40 min; wall thickness 325 µm when wet).

The standard bending bars finished with the alcohol size were then placed in a furan resin form (dimensions 280 x 200 x 130 mm) undiluted with a conventional zircon-containing size (zircon fluid 1219 from Hüttenes-Albertus GmbH) and placed in this form cast iron lying down (casting temperature approx. 1440 ° C; approx. 3.09 wt.% carbon content, approx. 1.89 wt.% silicon content, in each case based on the total mass of the cast iron), so that the standard -Bending bars were completely enclosed by the iron casting and were subjected to a maximum load during casting in relation to the bearing load (due to the iron as casting metal).

• Die Überreste des Standard-Biegeriegels B-Cold-Box (Vergleich) waren auf die vorstehend angegebene Weise kaum aus dem Eisen-Gussstück zu entfernen; sie blieben fast vollständig im Eisen-Gussstück zurück.
• Die Überreste der Standard-Biegeriegel B-V6 (nach dem erfindungsgemäßen Verfahren hergestellt, ohne Vernetzungsschritt) und B-E6+ (nach dem erfindungsgemäßen Verfahren hergestellt, mit Vernetzungsschritt) waren auf die vorstehend angegebene Weise sehr gut und praktisch vollständig aus dem Eisen-Gussstück zu entfernen. Es blieben kaum sichtbare Überreste im Eisen-Gussstück zurück.

After the casting process, the remains of the standard bending bars were removed by turning the iron casting (so that the remains of the standard bending bars could fall out of the downward openings of the cavities of the iron casting created by the standard bending bars) and the unpacking behavior (gutting behavior) of the standard bending bars was assessed visually. The following observations were made:

• The remains of the standard B-Cold-Box bending bar (comparison) could hardly be removed from the iron casting in the manner described above; they remained almost entirely in the iron casting.
• The remains of the standard bending bars B-V6 (produced by the process according to the invention, without crosslinking step) and B-E6 + (produced by the process according to the invention, with crosslinking step) were very good and practically completely from the iron casting in the manner described above remove. There were hardly any visible remains in the iron casting.

From the aforementioned observations it can be seen that hardened moldings produced by the process according to the invention (here: standard bending bars B-V6 or B-E6 +, representative of the core, feeder or mold) show very good removability from the core and thus demouldability Comparative molded part (B-Cold Box) are clearly superior in this regard.

Example 7: Production of standard test specimens (standard bending bar and standard test cylinder) from insulating feed mass as a molding material mixture

The components listed in Table 5 below were used to produce molding material mixtures for insulating feeders. The molding material mixtures were prepared analogously to that given in Example 1 above.

Bending bars were then formed from the molding material mixtures obtained and cured to standard bending bars in a manner analogous to that in Example 2 above. Furthermore, standard test cylinders (height: 50 mm, diameter: 50 mm) according to the VDG standard P38 were produced by ramming from the molding material mixtures obtained and hardened analogously to Example 2 above, as hardened moldings (30 min at 210 ° C. in the circulating air - Drying oven for standard bending bars and standard test cylinders with molding material mixture F-E6 + (2)). In the case of the molding material mixture F-E6 + (2), the standard bending bars or standard test cylinders produced as described above correspond to hardened molded parts (with crosslinking step) in the sense of the invention.

The final strengths of the standard bending bars “B-Cold-Box” (comparison) and the standard bending bars B-E6 + (2) (produced according to the invention) were then determined, analogously to that given in Example 3 above. The results of all corresponding measurements are given in Table 5 below (mean values from 3 measurements in each case).

Table 5 also shows the respectively determined values of the gas permeability of the standard bending bars and standard test cylinders as well as their weight. The gas permeability is a test value that provides information about the structure compression. In the case of the feeder in particular, this is a characteristic value that can provide information about the sufficient removal of casting gases during the casting. Table 5: Components of molding material mixtures for insulating feeders component Molding material mixture F Cold Box (2) F-E6 + (2) Expanded perlite [parts by weight] 100 100 Aqueous PVAL mixture [parts by weight] 0 17.15 Aliphatic polyisocyanate [parts by weight] 0 1.45 Aqueous preparation of chitosan [parts by weight] 0 11.4 Cold-box activator 6324 [parts by weight] 9.0 0 Cold box gas resin 7241 [parts by weight] 9.0 0 Dimensions of standard test cylinder [g] 47 41 Gas permeability standard test cylinder 45 85 Flexural strength [N / cm ² ] bending bar (final strengths 350 300

The ingredients specified in Table 5 "aqueous PVAL mixture", "aliphatic polyisocyanate", "aqueous preparation of chitosan", "cold box activator 6324" and "cold box gas resin 7241" correspond to the ingredients specified in Example 1.

It can be seen from the results given in Table 5 above that an insulating feed mass produced by the method according to the invention had properties comparable to those of a feed mass produced by the cold box method known from the prior art.

Example 8: Casting molded parts with aluminum

From the insulating feed mass with molding material mixture “F-Cold-Box (2)” produced above in Example 7, isolating (gassing with catalyst N, N-dimethylpropylamine) was carried out in a manner known to the person skilled in the art by firing in a core shooting machine (closed at the bottom with a base) Manufactured.

From the insulating feed mass with molding material mixture “F-E6 + (2)” produced according to the invention in Example 7 above, insulating feeders were shot in the same shape (as with the feed mass “F-Cold-Box (2)”) on the core shooter. The curing was carried out for 30 min at 210 ° C. with dehydration in a drying cabinet (circulating air).

Insulating feeders produced in the above-mentioned manner from the two molding material mixtures used were placed in a sand mold bonded with a cold box and cast in each case with aluminum to test their behavior under metal casting conditions. Further insulating feeders likewise produced in this way were placed in loose molding sand and cast in each case with iron instead of aluminum.

• Beim Abguss mit Aluminium des mit der Vergleichs-Formstoffmischung F-Cold-Box (2) (nicht nach dem erfindungsgemäßen Verfahren) hergestellten isolierenden Speisers wurde starke Qualmbildung beobachtet, die auch nach Entnahme des abgegossenen Speisers aus der Sandform anhielt.
• Beim Abguss mit Aluminium der mit der Formstoffmischung F-E6+ (2) (nach dem erfindungsgemäßen Verfahren) hergestellten isolierenden Speiser wurde keine Qualmbildung festgestellt. Nach dem Abguss zeigte der erfindungsgemäß hergestellte isolierende Speiser ein deutlich besseres Auspackverhalten als der mit der Vergleichs-Formstoffmischung F-Cold-Box (2) hergestellte isolierende Speiser, d.h. der erfindungsgemäß hergestellte isolierende Speiser ließ sich deutlich leichter vom Aluminium trennen. Die entstandenen Aluminium-Gussstücke zeigten eine deutlich sauberere Oberfläche (d.h. keine Kondensatbeläge) als die Aluminium-Gussstücke, welche mit dem mit der Vergleichs-Formstoffmischung F-Cold-Box (2) hergestellten isolierenden Speiser hergestellt worden waren.

The following observations were made:

• When casting with aluminum of the insulating feeder produced with the comparison molding material mixture F-Cold-Box (2) (not according to the method according to the invention), strong smoke formation was observed, which continued even after the cast feeder was removed from the sand mold.
• When casting with aluminum the insulating feeders produced with the molding material mixture F-E6 + (2) (according to the method according to the invention), no smoke formation was found. After the casting, the insulating feeder produced according to the invention showed a significantly better unpacking behavior than the insulating feeder produced with the comparative molding material mixture F-Cold-Box (2), ie the insulating feeder produced according to the invention was much easier to separate from the aluminum. The resulting aluminum castings showed a significantly cleaner surface (ie no condensate deposits) than the aluminum castings, which had been produced with the insulating feeder produced with the comparative molding material mixture F-Cold-Box (2).

Example 9: Sample of iron cubes

The molding material mixtures given below in Table 6 were each formed into (insulating) feeders in a core shooter in a manner known to the person skilled in the art.

In the case of the feeder mixture “F-Cold-Box (3)”, curing was carried out in a manner known to the person skilled in the art by gassing with the catalyst N, N-dimethylpropylamine. In the case of the feeder mixture "F-water glass (2)" the curing took place for 25 min at 210 ° C in a drying cabinet (circulating air). In the case of the feeder mass "F-E6 + (3)", the cross-linked, hardened molded part was cured by heating and removing water for 30 min at 210 ° C. in a drying cabinet (circulating air). This resulted in the feeders “Speiser-Coldbox” and “Speiser-Wasserglas” which were not produced according to the invention and the feeder produced according to the invention “Speiser-B-E6 +”. Table 6: Compositions of molding material mixtures for feeders component Molding material mixture F Cold Box (3) F water glass (2) F-E6 + (3) Quartz sand [parts by weight] 100 100 100 Aqueous PVAL mixture [parts by weight] 0 0 3.43 Aliphatic polyisocyanate [parts by weight] 0 0 0.29 Aqueous preparation of chitosan [parts by weight] 0 0 2.28 Cold-box activator 6324 [parts by weight] 1.2 0 0 Cold box gas resin 7241 [parts by weight] 1.2 0 0 Soda water glass binder 48/50 [parts by weight] 0 1.5 0

The constituents specified in Table 6 each correspond to the constituents specified in Example 1 or their meanings.

The above-mentioned feeders were each checked for their usability, in particular the quality of their feed effect, by use in the test casting of an iron cube (model for a metallic casting). For this purpose, the feeders of the same size (i.e. the same module in each case) were used for the sample casting of cubes of the module (i.e. with a volume to surface ratio of) 1.68 cm with iron (GGG40) at a casting temperature of 1400 ° C. For the quality assessment, the specialist in the field of foundry technology often uses cubes that have a significantly higher module than the feeders, in order to be able to obtain the best possible information on solidification from the test. The quality of the feeding effect is recorded via the depth of the blow hole reaching into the cube, whereby blow holes reaching deeper into the cube (the metal casting) mean a poorer feeding effect.

• Bei Verwendung eines nicht-erfindungsgemäß hergestellten Cold-Box-gebundenen Speisers fand unter den Versuchsbedingungen eine deutliche Lunkerbildung statt, welche bis in das metallische Gussstück hineinreichte.
• Bei Verwendung eines nicht-erfindungsgemäß hergestellten Wasserglas-gebundenen Speisers fand unter den Versuchsbedingungen eine ausgeprägte Lunkerbildung statt, welche bis weit in das metallische Gussstück hineinreichte. Die unter den Versuchsbedingungen geringe Güte der Speiserwirkung des Wasserglas-gebundenen Speisers ist hier vermutlich auf die vergleichsweise hohe Wärmeenergie-Aufnahme des Wasserglas-Binders (bekannt als dessen unvorteilhaftes „Abschreckverhalten“) zurückzuführen und die daraus resultierende verhältnismäßig frühe Erstarrung des Gießmetalls.
• Bei Verwendung des erfindungsgemäß hergestellten Speisers „Speiser-B-E6+“ traten dagegen keine Lunker im metallischen Gussstück auf, sondern im Wesentlichen nur am oberen Ende des metallischen Restspeisers.

After the casting and cooling to room temperature, the sample cubes produced as above were sawn (halved) in the middle in order to expose their cross-section and to assess the quality of the casting and the quality of the feed effect of the feeders used in each case. The cross sections of the test cubes obtained by sawing with the visible residual feeder made of iron placed on top were visually assessed, with the results given below:

• When using a cold-box-bound feeder not produced according to the invention, a clear void formation took place under the test conditions, which reached right into the metallic casting.
• When using a water glass-bound feeder not produced according to the invention, a pronounced void formation took place under the test conditions, which reached far into the metal casting. The low quality of the feed effect of the water glass bound feeder under the test conditions is presumably due to the comparatively high heat energy absorption of the water glass binder (known as its disadvantageous "quenching behavior") and the resulting relatively early solidification of the cast metal.
• By contrast, when using the feeder “Speiser-B-E6 +” produced according to the invention, there were no voids in the metallic casting, but essentially only at the upper end of the residual metal feeder.

It can therefore be concluded from the observations given above that a feeder produced according to the invention has a significantly improved feeding capacity than the conventional cold box or water glass-bound feeders used for comparison.

Example 10: Production of aqueous binder systems

The ingredients listed in Table 7 below were used to prepare aqueous binder systems. Table 7: Components of aqueous binder systems component Aqueous binder systems WB-V6 WB-E6 + Aqueous PVAL mixture [parts by weight] 60.00 57.14 Aliphatic polyisocyanate [parts by weight] 0 4.76 Aqueous preparation of chitosan [parts by weight] 40.00 38.10

The constituents given in Table 7 “aqueous PVAL mixture”, “aliphatic polyisocyanate” and “aqueous preparation of chitosan” correspond to the constituents specified in Example 1.

The aqueous binder systems WB-V6 and WB-E6 + are aqueous binder systems to be used according to the invention. The aqueous binder system WB-E6 + corresponds to an aqueous mixture described above as the second binder system.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102007031376 A1 [0021]
• DE 19615400 A1 [0021]
• EP 677346 A2 [0021]
• WO 9626231 A1 [0021]
• WO 2011/044003 A2 [0021]
• WO 2017/071695 A1 [0021, 0077]
• DE 102007026166 A1 [0068]
• WO 2008/113765 A1 [0111]
• WO 2017/093371 A1 [0111]
• WO 2017/174826 A1 [0111]
• WO 2013/014118 A2 [0111]

Non-patent literature cited

• DIN EN ISO 15023-02 2017-02 [0068]
• DIN 53015: 2001-02 [0068, 0078, 0080]

Claims (15)

Method i) for producing a metallic casting and / or ii) for producing a hardened molded part selected from the group consisting of casting mold, core and feeder, for use in casting metallic castings, with the following steps: V1) producing a molding material mixture comprising the the following constituents: a) at least one basic molding material, b) one or more aliphatic polymers each comprising structural units of the formula I containing hydroxyl groups -CH ₂ -CH (OH) - (I), c) as hardener component, one or both constituents selected from the group consisting of: c1) one or more biopolymers selected from the group of poly-D-glucosamines and c2) one or more polyisocyanates, as crosslinking agents for hydroxyl groups of the aliphatic polymer or polymers ; and d) water; V2) shaping the molding material mixture, and then V3) hardening the molded molding material mixture or a resultant, non-hardened secondary product in one or more steps, so that a hardened molding results. Procedure according to Claim 1 , wherein - the molding material mixture as hardener component c) comprises component c1), one or more biopolymers selected from the group of poly-D-glucosamines, and / or - the hardening in step V3) includes V31) the precipitation of at least portions of the one or more biopolymers, preferably by increasing the pH of the aqueous portions of the shaped molding material mixture, particularly preferably by contacting, preferably gassing, with an alkaline gaseous compound, very particularly preferably by gassing with a gaseous amine, so that a green-stable molded part results ; and / or V32) the treatment of the shaped molding material mixture and / or the resulting, not hardened secondary product and / or the green-stable molded part, - by heating the molded molding material mixture and / or the resulting, uncured secondary product and / or the green-stable molded part, preferably to a temperature in the range from 100 ° C. to 300 ° C., particularly preferably in the range from 150 ° C. to 250 ° C. and very particularly preferably in the range from 180 ° C. to 230 ° C., and / or by removing water from the molded molding material mixture and / or from the resulting, non-hardened follow-up product and / or from the molded part which is stable on greenery. Method according to one of the preceding claims, preferably according to Claim 2 , wherein - the molding material mixture as hardener component c) comprises component c2), one or more polyisocyanates, preferably aliphatic polyisocyanates, and / or - the curing in step V3) comprises V32) treating the molded molding material mixture and / or the resulting product resulting therefrom and / or the green part which is resistant to green standing, preferably - by heating the shaped molding material mixture and / or the resulting product and / or the green part which is stable to green standing, preferably to a temperature in the range from 100 ° C. to 300 ° C., particularly preferably in the range of 150 ° C to 250 ° C and very particularly preferably in the range of 180 ° C to 230 ° C, and / or - by removing water from the molded molding material mixture and / or from the resulting uncured follow-up product and / or from the green-stable molded part , and preferably V33) the crosslinking of hydroxyl groups of the aliphatic polymer (s) of the formula I with isocyan at groups of the polyisocyanates in the molded molding material mixture and / or in the resulting product and / or in the green-resistant molded part, so that a crosslinked molded part results as a hardened molded part. Method according to one of the preceding claims, wherein the aliphatic polymers used each comprising hydroxyl-containing structural units of the formula I. - Can be produced by at least partial saponification of polyvinyl acetate; and or - are selected from the group consisting of polyvinyl alcohols, polyvinyl acetates and mixtures thereof and or ≥ 75% by weight, preferably ≥ 90% by weight, particularly preferably ≥ 98% by weight, of the total mass of the molding material mixture, in addition to the one or more biopolymers used as component c1), selected from the group of poly- D-glucosamines, total organic polymers comprising hydroxyl groups used, and or comprise one or more polyvinyl alcohols, preferably all of the polyvinyl alcohols used has a degree of hydrolysis of> 50 mol%, preferably determined according to the method as specified in document DE 10 2007 026 166 A1, paragraphs [0029] to [0034], and particularly preferably has a degree of hydrolysis in the range from 70 mol% to 100 mol%, very particularly preferably in the range from 80 mol% to 100 mol%, preferably determined according to the method according to DIN EN ISO 15023-02 2017-02 Draft, Appendix D, and or has a dynamic viscosity in the range from 0.1 to 30 mPas, preferably in the range from 1.0 to 15 mPas, particularly preferably in the range from 2.0 to 10 mPas, each determined at a 4% -igen (w / w) aqueous solution of all of the polyvinyl alcohols used at 20 ° C according to DIN 53015: 2001-02; and or ≥ 75% by weight, preferably 90 90% by weight, particularly preferably 98 98% by weight, of the total mass of the aliphatic polymers used overall in the molding material mixture in each case comprising structural units of the formula I containing hydroxyl groups. Method according to one of the preceding claims, wherein - the one or one or more of the several biopolymers selected from the group of poly-D-glucosamines comprise chitosan, the chitosan preferably - a degree of deacetylation of> 70 mol%, preferably of> 75 mol -% and particularly preferably of> 80 mol%, determined by means of ¹ H-NMR spectroscopy, and / or - a dynamic viscosity of> 500 mPa · s, preferably of> 600 mPa · s, particularly preferably of ≥ 700 mPa · S, each determined on a 1% (w / w) solution of chitosan in 1% (w / w) acetic acid at 20 ° C according to DIN 53015: 2001-02, and / or - the ratio of Sum - the total mass of the aliphatic polymers used, each comprising hydroxyl-containing structural units of the formula I and - the total mass of biopolymers used selected from the group of poly-D-glucosamines, for the - total mass of the molding material used, in the range from 0.2: 100 to 13: 100, preferably in the range from 0.3: 100 to 10: 100, particularly preferably in the range from 0.5: 100 to 9: 100. Method according to one of the preceding claims, wherein the one or more polyisocyanates comprise aliphatic polyisocyanates, wherein - the one or one or more or all of the several aliphatic polyisocyanates are nonionically or ionically hydrophilized, and / or - the one or one or more or all of the plurality of aliphatic polyisocyanates comprise or comprise a polyether group or a sulfonate group, and / or - the one or one or more or all of the plurality of aliphatic polyisocyanates comprise a polyether group and additionally comprise a urethane and / or an allophanate group, and / or - the one or one or more or all of the several aliphatic polyisocyanates comprises or comprise one or more 2,4,6-trioxotriazine groups and preferably comprises or comprises a polyether group or a sulfonate group, preferably a polyether group, and / or - the one or one or more or all of the several aliphatic poles yisocyanates comprise or comprise one or more 2,4,6-trioxotriazine groups and a polyether group and also a urethane and / or an allophanate group, preferably a urethane group, and / or - the one or more aliphatic polyisocyanates used ≥ 50% by weight, preferably ≥ 75% by weight, particularly preferably 90 90% by weight and very particularly preferably 98 98% by weight, of the one or more used overall in the molding material mixture Make out polyisocyanates. Method according to one of the preceding claims, in which - The relationship the sum - The total mass of the aliphatic polymers used, each comprising hydroxyl-containing structural units of the formula I and - The total mass of biopolymers used selected from the group of poly-D-glucosamines The total mass of the preferably aliphatic polyisocyanates used as crosslinking agents is in the range from 1: 1 to 10: 1, preferably in the range from 1.5: 1 to 7.5: 1, particularly preferably in the range from 2: 1 to 5: 1 . Method according to one of the preceding claims, the basic molding material comprising: - One or more particulate refractory solids selected from the group consisting of Oxides, silicates and carbides, each comprising one or more elements from the group consisting of Si, Al, Zr, Ti, Mg, Fe and Ca, Mixed oxides, mixed carbides and mixed nitrides, each comprising one or more elements from the group consisting of Si, Al, Zr, Ti, Mg, Fe and Ca, and - graphite and / or one or more particulate light fillers, preferably selected from the group consisting of: Core-shell particles, preferably having a glass core and a refractory shell, particularly preferably with a bulk density in the range of 470-500 g / L; - refractory composite particles; - Spheres; - pearlite, preferably expanded pearlite; - closed-pore micro-balls made of expanded pearlite; - rice bowl ash; - expanded glass, - hollow glass spheres, and - Ceramic hollow spheres, preferably hollow spherical corundum. Method i) for producing a metallic casting according to one of the preceding claims, preferably according to one of the Claims 2 to 8th , with the following additional step: V4) contacting the hardened molded part, preferably as obtained after step V32) and preferably additionally step V33), with a cast metal for producing a metallic casting, the cast metal preferably solidifying in contact with the hardened molded part, preferably - The casting metal is selected from the group consisting of aluminum, magnesium, tin, zinc and their alloys and / or - The temperature of the casting metal during casting is not higher than 900 ° C; so that a metallic casting results. Hardened molded part, preferably producible by a method according to one of the Claims 1 to 9 , selected from the group consisting of mold, core and feeder, for use in the casting of metallic castings, comprising a) at least one basic molding material, b) one or more aliphatic polymers, each comprising structural units of the formula I containing hydroxyl groups -CH ₂ -CH (OH) - (I), and c) as hardener component, one or both components selected from the group consisting of: c1) one or more, preferably precipitated, biopolymers selected from the group of poly-D-glucosamines and c2) one or more, preferably aliphatic, polyisocyanates, preferably the hydroxyl groups of the aliphatic polymers used, each comprising at least partially structural units of the formula I containing hydroxyl groups are present as a binder which is hardened, preferably crosslinked, hardened by crosslinking with isocyanate groups of the one or more polyisocyanates used. Green-shaped molded part after Claim 10 comprising, as hardener component c), component c1), one or more precipitated biopolymers selected from the group of poly-D-glucosamines, preferably comprising chitosan. Hardened molded part after Claim 10 or 11 comprising, as hardener component c), component c2), one or more, preferably aliphatic, polyisocyanates, the hydroxyl groups of the aliphatic polymers used in each case comprising at least partially structural units of the formula I containing hydroxyl groups being at least partially crosslinked by crosslinking with isocyanate groups of the one or more polyisocyanates used , hardened, binder. Molding material mixture comprising the following constituents: a) at least one basic molding material, b) one or more aliphatic polymers each comprising structural units of the formula I containing hydroxyl groups -CH ₂ -CH (OH) - (I), c) as hardener component, one or both constituents selected from the group consisting of: - one or more biopolymers selected from the group of poly-D-glucosamines and - one or more, preferably aliphatic, polyisocyanates, as crosslinking agents for hydroxyl groups or aliphatic polymers; and d) water. Use of an aliphatic polymer crosslinked by one or more aliphatic polyisocyanates comprising structural units of the formula I containing hydroxyl groups -CH ₂ -CH (OH) - (I), preferably a polyvinyl alcohol crosslinked in this way, as a binder of a molded part selected from the group consisting of mold, core and feeder, for use in the casting of metallic castings. Use of biopolymers selected from the group of poly-D-glucosamines, preferably chitosan, as a binder or binder component for producing a hardened molded part, preferably a green-resistant molded part, selected from the group consisting of mold, core and feeder, in the foundry industry.