BG64942B1 - Binder system for producing melting moulds and polyurethane-based cores - Google Patents

Abstract

The present invention relates to a binder system that comprises a phenolic-resin component and a polyisocyanate component. The system is characterised in that the phenolic-resin component includes analkoxy-modified phenolic resin, wherein less than 25 mole % of the phenolic hydroxy groups are etherified with a primary or secondary aliphatic alcohol comprising between 1 and 10 carbon atoms.

Description

Technical field

The present invention relates to a binder for the production of foundry hearts and polyurethane-based foundry molds.

BACKGROUND OF THE INVENTION

The well-known method of making casting hearts, now known as the Cold-Boxing Method or Ashland Method, has a leading role in the foundry industry, and a two-component polyurethane system (agent) is used to connect the casting mixture. The first component of the agent consists of a polyol solution containing at least two OH groups per molecule. The second component is a solution of polyisocyanate with at least two NCO groups per molecule. Hardening of the binder is carried out using basic catalysts. Liquid bases can be mixed with the binder prior to forming to react between the two components (US-A-3 676 392). Another possibility according to US-A-3 409 579 consists in passing gaseous tertiary amines through the mixture consisting of a molding agent / binder after molding.

In both of these patents, phenolic resins are used as polyols, which are obtained by condensation of phenol with aldehydes, preferably formaldehyde, in the liquid phase at temperatures up to about 130 ° C in the presence of catalytic amounts of metal ions. US-A-3 485 797 describes in detail the preparation of such phenolic resins. In addition to unsubstituted phenols, substituted phenols, preferably o-cresol and p-nonylphenol (e.g., EP-A-183 782), may be used, and other reaction components to produce the phenolic resin according to EP-B-0 177 871 may aliphatic mono-alcohols having one to eight carbon atoms are indicated. During the alkoxylation, the binder must have increased thermal stability. Preferably, mixtures of high-boiling polar solvents (such as esters and ketones) and high-boiling aromatic hydrocarbons are used as the solvent for the phenolic component. In contrast, polyisocyanates dissolve predominantly in high boiling aromatic hydrocarbons. EP-A-0 771 599 discloses such a formulation whereby the use of fatty acid methyl esters achieves complete or substantially limited application of aromatic solvents. The fatty acid methyl esters can be used in this case either as stand alone solvents or after the addition of highly polar solvents (phenolic component) such as aromatic solvents (isocyanate component). The casting hearts obtained with these binders are extremely easy to separate from the mold.

In practice, however, the binders specified in EP-A-0 771 590 show a certain disadvantage: they produce smoke and smoke during casting, which in many foundries cannot be eliminated during testing.

In order to meet the ever-increasing standard of environmental and occupational safety requirements, in recent years there has been an increasing interest in binders that do not contain or contain very little aromatic hydrocarbons.

It is an object of the present invention to provide a binder that does not contain aromatic substances or are present in minimal quantities. It is also an object of the present invention to provide a binder which, during casting, causes a limited amount of smoke to be released. Molded bodies obtained with this binder must have good flexural strength and, above all, instantaneous strength.

This problem is accomplished by a binder comprising one phenolic resin component and one polyisocyanate component, wherein the phenolic resin component comprises an alkoxy-modified phenolic resin in which less than 25 mol% of the phenolic hydroxyl groups are esterified with one primary or secondary aliphatic alcohol of 1 to 10 carbon atoms.

The invention also relates to molding mixtures, aggregates containing up to 15% by weight. % by weight of the binder described in the invention.

The invention also relates to a method for producing molded parts, comprising:

a) mixing the aggregate mixture with a binder described in the invention in an amount up to 15 wt. % by volume of the mixture;

b) filling the mold with the casting mixture obtained in step (a);

c) solidifying the mold mixture in the mold to maintain the shape obtained; and

d) finally separating the mold cast obtained in step (c) from the mold and further curing to give a solid, solid, hardened molding part.

The molding part thus obtained can be used according to the invention for casting metal.

Of particular importance in the present invention is the selection of an alkoxymodified phenolic resin having a low viscosity and a suitable polarity. The alkoxymodified phenolic resin makes it possible, according to the invention, to reduce the amount of solvent required, both in the phenolic resin component and in the isocyanate component. Furthermore, it becomes possible to eliminate the use of aromatic hydrocarbons in one or even the two components. By combining an alkoxymodified phenolic resin with a rich in siloric content, a polar, organic solvent makes it possible to improve the instantaneous strength of the smoke by reducing the formation of smoke. The addition of a fatty acid ester has a positive effect on the resolution and moisture resistance.

Phenolic mixtures are obtained by condensation of phenols with aldehydes (Ullmann's Encyclopedia of Industrial Chemistry, Bd. A 19, page 371 ff, 5th Auflage, VCH Verlag, Weinheim). Substituted phenols and mixtures thereof may be used in conjunction with the phenol within this invention. All substituted phenols used so far are suitable. Phenolic compounds are not substituted at both the ortho-sites and at the ortho- and para-sites to allow polymerization to proceed. The remaining carbons on the ring can be substituted. The selection of substituents is not particularly limited insofar as these substituents do not adversely affect the polymerization process of the phenol with the aldehyde. Examples of substituted phenols are alkyl substituted phenols, aryl substituted phenols, cycloalkyl substituted phenols, alkenyl substituted phenols, alkoxy substituted phenols, aryloxy substituted phenols, and halogen substituted phenols.

The substituents mentioned above have from 1 to 26, preferably from 1 to 12, carbon atoms. O-cresol, presol, p-cresol, 3,5-xylene, 3,4-xylene may be mentioned as suitable phenols together with particularly preferred unsubstituted phenols,

3.4.5-Trimethylphenol, 3-ethylphenol, 3,5-diethylphenol, p-butylphenol, 3,5-dibutylphenol, p-amylphenol, cyclohexylphenol, p-octylphenol,

3,5-dicyclohexylphenol, p-croethylphenol, p-phenylphenol, 3,5-dimethoxyphenol, 3,4,5-trimethoxyphenol, p-ethoxyphenol, p-butoxyphenol, 3-methyl-4-methoxyphenol and p-phenoxyphenol. The phenol itself is particularly suitable. Phenols can be described by the following general formula

HE

wherein A, B and C may be hydrogen, alkyl, alkoxy or halogen.

All the aldehydes used so far to prepare phenolic resins can also be used in the present invention. Formaldehyde, acetaldehyde, propionaldehyde, furfuraldehyde and benzaldehyde may be exemplified. Preferred are aldehydes of the general formula R'CHO in which R 'represents hydrogen or a hydrocarbon radical of 1 to 8 carbon atoms. Formaldehyde is particularly suitable and preferred, both in its aqueous form and as paraformaldehyde.

In order to obtain the phenolic resins according to the invention, at least an equivalent molar amount of aldehyde per molar amount of the phenolic component must be used. Preferably the molar ratio of aldehyde: phenol is at least 1: 1.0, but particularly preferably at least 1: 0.58.

To obtain alkoxy-substituted phenolic resins, primary or secondary aliphatic alcohols with one OH group and with 1 to 10 carbon atoms are used. Suitable primary or secondary alcohols include, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol and hexanol. Alcohols with 1 to 8 carbon atoms, in particular methanol and butanol, are suitable.

The preparation of alkoxy-substituted phenolic resins is described in EP-B-0 177 871. They can be prepared either by one-step or two-step methods.

In the one-step process, the interaction between the phenolic component, the aldehyde and the alcohol takes place in the presence of a suitable catalyst. In the two-step process, an unsubstituted resin is obtained, which is finally treated with alcohol.

The ratio of alcohol to phenol affects the properties of the resin as well as the reaction rate. The molar ratio of alcohol to phenol is less than 0.25, so that less than 25 mol% of the phenolic hydroxyl groups are esterified. A molar ratio of 0.18-0.25 is appropriate. When the molar ratio of alcohol to phenol is greater than 0.25, then the moisture resistance decreases.

Suitable catalysts are the salts of divalent ions of manganese, zinc, cadmium, magnesium, cobalt, nickel, iron, lead, calcium and barium. Zinc acetate is particularly preferred.

Alkoxylation results in resins of limited viscosity. The resins have substantially ortho-ortho benzyl ether bonds and also have ortho- and para-sites to the phenolic OH groups of alkoxymethylene groups of the general formula - (CH ₂ O) _n R. Here R is the alkyl group of the alcohol, and η means one small integer ranging from 1 to 5.

All solvents commonly used in binders for the foundry industry can also find application in the agents of the present invention. However, the use of aromatic hydrocarbons in larger quantities as an integral part of the solvent may not, however, eliminate the environmental and health-damaging solvents mentioned in the beginning. Preferably, solvents having a high oxygen content, both polar and organic, may be used as the solvent of the phenolic resin component. Preferably, esters of dicarboxylic acids, glycolester, glycol diester, glycol dieter, cyclic ketones, cyclic esters (lactones) or cyclic carbonates are preferred. Dicarboxylic acid esters, cyclic ketones and cyclic carbonates are preferably used. Dicarboxylic acid esters have the general formula R ^ OC-Rj-COORp in which R _t independently denotes an alkyl group of 1 to 12 (but preferably 1 to 6) carbon atoms, and R ₂ means an alkylene group of 1 up to 4 carbon atoms. Examples are the dimethyl esters of carboxylic acids of 4 to 6 carbon atoms, which are obtained under the name "dibasic esters" and are from DuPont. Glycol ethers are compounds of the general formula R ₃ -OR ₄ -OOCR ₅ in which R ₃ represents an alkyl group of 1 to 4 carbon atoms, R ₄ means an alkylene group of 2 to 4 carbon atoms and R ₅ means an alkyl group with 1 to 3 carbon atoms (for example butylglycol acetate), but preferably they are glycoleteracetates. The glycol diesters conform to the general formula R _S COO-R ₄ -OOCR ₅ , in which R ₄ and R ₅ have the meanings given above, and R _{5 are} always independently selected from one another (eg propylene glycol diacetate), but are preferably glycol diacetates . Glycoldieters are characterized by the general formula R ₃ OR.-OR ,, in which R and R. have the meanings given above, and the residues R _{3 are} always selected independently of one another (eg dipropylene glycol dimethyl ether). Also suitable are cyclic ketones, cyclic esters and cyclic carbonates with 4 to 5 carbon atoms (such as propylene carbonate). The alkyd and alkylene groups may be branched or unbranched. These organic polar solvents can be advantageously used either as stand alone solvents of the phenolic resin or in combination with fatty acid esters, the content of the oxygen-rich solvent in the solvent mixture being predominant. The oxygen-rich solvent content should be greater than 50% by weight. %, preferably more than 55 wt. %.

The degree of reduction of the total amount of solvent in the binder has a positive effect on the formation of smoke. While the phenolic resins known so far contain predominantly about 45 wt. % and in part up to 55 wt. % solvent, in order to achieve a processing viscosity (about 400 mPa.s), it is possible to reduce the percentage of solvent in the phenolic component to a maximum of 40 wt.% by using a low viscous phenolic resin according to the present invention. %, but preferably up to 35% by weight. %. Dynamic viscosity is determined, for example, by the Brookfield Dreh spindel method.

When using the hitherto unmodified alkoxy phenolic resins, the viscosity of the reduced solvent is far beyond the favorable technical range to about 400 mPa.s. In part, the solubility is so poor that even at room temperature phase separation is observed. At the same time, the material strength of the foundry hearts obtained with this binder drops to a very low level. The preferred binders exhibit an instantaneous strength of at least 150 N / cm ² using 0.8 wt. pp. of the phenolic resin component and the isocyanate component relative to 100 wt. h. aggregate such as quartz sand H32 (see EP-A-0 771 599 or DE-A-4 327 292).

The addition of a fatty acid ester to the solvent of the phenolic component results in particularly good separating properties. Suitable fatty acids, for example, are 8 to 22 carbon atoms that are esterified with aliphatic alcohol. Fatty acids are commonly used, which are natural products such as tall oil, rapeseed oil, sunflower oil, germ oil and coconut oil. Instead of natural oils, which in most cases are a mixture of different fatty acids, separate, stand alone fatty acids such as palmitic acid or myristic acid may also be used.

Aliphatic mono alcohols of 1 to 12 carbon atoms are suitable for the esterification of fatty acids. Alcohols having 1 to 10 carbon atoms are preferred, in particular such alcohols having 4 to 10 carbon atoms. Based on the limited polarity of the fatty acid esters, whose alcohol component has from 4 to 10 carbon atoms, it is possible to reduce the amount of fatty acid ester and to avoid the formation of smoke. A number of fatty acid esters are commercially available.

It has surprisingly been found that fatty acid esters, the alcohol component of which contains 4 to 10 carbon atoms, are particularly suitable because they provide the binder with excellent separation properties even when the content of the phenolic component in a solvent is less than 50 wt. . %. Examples of fatty acid esters with a longer alcohol component may be fatty acid and tallic acid butyl esters as well as mixed tallic acid octyl / decyl esters.

The use of alkoxy-substituted phenolic resins according to the present invention can eliminate the use of aromatic hydrocarbons as solvents of the phenolic component. It can be recovered by measuring the viscosity of the polarity of the compounds that make it possible to use oxygen-rich, organic, polar solvents, for example as stand alone solvents. The use of alkoxy-substituted phenolic resins according to the present invention makes it possible to reduce the amount of solvent to less than 35 wt. % in the phenolic component. This is made possible by the reduced viscosity of the resin. Thus, the use of aromatic hydrocarbons can be eliminated. The use of a binder according to the present invention, which means contains at least 50 wt. % of the above oxygen-rich, polar, organic solvents as a component of the solvent of the phenolic component results in a pronounced reduced formation of smoke compared to the previously known agents containing a large amount of fatty esters in the solvent.

The second component of the binder comprises an aliphatic, cycloaliphatic or aromatic polyisocyanate, preferably with 2 to 5 isocyanate groups. Depending on the desired properties, mixtures of organic isocyanates may also be used. Suitable polyisocyanates include aliphatic polyisocyanates such as hexamethylenediisocyanate, alicyclic polyisocyanates such as 4,4'-dicyclohexylmethane diisocyanate and dimethyl derivatives. Examples of suitable aromatic polyisocyanates may include toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, 1,5-naphthalenediisocyanate, triphenylmethanotriisocyanate, xylylenediisocyanate, and methyl derivatives, such as polymethylenepolylethenylenolate; . Preferred polyisocyanates are aromatic polyisocyanates, especially polymethylene polyphenylpolyisocyanates such as diphenylmethane diisocyanate.

In general, 10 to 500 wt. % polyisocyanate by weight of phenolic resin. Preferably 20 to 300 wt. % polyisocyanate. Liquid polyisocyanates are used in undiluted form, while solid and viscous isocyanates are dissolved in organic solvents. Up to 80 wt. % of the isocyanate component to be solvent. As the solvent for the polyisocyanate, both the fatty acid esters mentioned above and a mixture of fatty acid esters of up to 50% by weight can be used. % aromatic solvents. Suitable aromatic solvents are naphthalene, alkyl substituted benzenes and mixtures thereof. Aromatic solvents, which are a mixture of the aromatic solvents mentioned above, having a boiling range between 140 ° C and 230 ° C are particularly preferred. However, it is preferable not to use any aromatic solvent. Preferably, the polyisocyanate is used in such an amount that the number of isocyanate groups is from 80 to 120% of the number of free hydroxyl groups of the resin.

In addition to the components already mentioned, the binder may also contain conventional additives, such as silanes (US 4,540,724) / dry oils (US 4,268,425) or complexing agents (WO1995 / 003903). Preferably binders are available as two-component systems in which one component is the phenolic resin solution and the other component is the polyisocyanate, optionally in solution. The two components are mixed and finally mixed with sand or similar aggregate to form a molding mixture. The molding mixture contains an active bound amount of binder according to the invention, which is up to 15 wt. % by weight of unit. It is also possible to mix the components with a part of the sand or aggregate and finally mix the two mixtures. Methods for preparing a homogeneous mixture of components and assembly are known to those skilled in the art. The mixture may additionally contain other conventional additives, such as iron oxide, ground flat fibers, wood particles, resins and refractory flours, as needed.

In order to obtain sand molding bodies, the aggregate must have a sufficiently large particle size. In this way, the molding body has sufficient porosity and the volatiles are evaporated during casting. In general it can be said that at least 80 wt. but preferably 90 wt. % of the assembly have an average particle size less than or equal to 290 pm. The average particle size of the assembly must be between 100 and 300 pm.

For standard molding bodies, it is preferable to use sand as an aggregate material of at least 70 wt. but preferably more than 80% by weight. % of the sand is silica. Also suitable as aggregating materials are zircon, silt, aluminum silicate sand and chromite sand.

Aggregation material is the main constituent of molding bodies. For standard use, sand molding bodies contain a binder in an amount typically up to 10 wt. %, more commonly between 0.5 and 7 wt. % by weight of unit. Particularly preferred is a binder in an amount of 0.6 to 5 wt. % by weight of unit.

As long as the unit is predominantly dried, humidity up to 0.1 wt is preferred. % by weight of unit. The molding body hardens so that it retains its outer shape after the mold is removed. Conventional liquid or gaseous hardeners can be used to cure the binder according to the present invention. In this way it is possible, for example, for an easily volatile tertiary amine such as triethylamine or dimethylethylamine, as described in USA-3 409 579, to pass through the foundry molded part. It is also possible to add a liquid amine to solidify the molding mixture. After removal from the mold, a further hardening of the molded material is carried out in a manner known per se in order to reach its final state.

In a preferred embodiment, silanes of the general formula (R 'O) ₃ Si are added to the molding mixture prior to curing. In this formula, R 'means one hydrocarbon radical, preferably one alkyl radical of 1 to 6 carbon atoms, and R means one alkyl radical, one alkoxy substituted alkyl radical, or an alkylaminosubstituted amine radical with alkyl groups having from 1 to 6 carbon atoms . The additive from 0.1 to 2 wt. % by weight of the binder and the hardener reduces the sensitivity of the binder to moisture. Examples of commercially available silanes are Dow Corning Z6040 and Union Carbide A-187 (gamma-glycidoxypropyltrimethoxysilane), Union Carbide Al 100 (gamma-aminopropyltriethoxysilane), Union Carbide Al 120 (1H-beta- (aminoethyl)-gamma-aminopropyltrimethoxymethyltrimethoxymethylmethoxypropyltrimethoxymethylmethoxypropyltrimethoxymethylmethoxypropyltrimethoxymethyl Carbide Al 160 (ureidosilane).

Other additives, including wetting agents, may be used as appropriate, and sand mixtures may be used as additives, as described in US 4 683 252 and US 4 540 724. Additionally, mold separators may be used. such as fatty acids, fatty alcohols and their derivatives, but in principle this is not a requirement.

Examples of carrying out the invention

The invention is illustrated by the following examples.

Examples

Unless otherwise stated, all percentages of data should be understood as weights. %.

1) Preparation of phenolic resin

In a reflux condenser, thermometer, and stirrer, the reactors are charged as indicated in Table I. With continuous stirring, the temperature is increased uniformly to 105115 ° C and maintained for as long as necessary to achieve an index. of refraction 1/5590. The cooler was then switched to distillation and the temperature raised to 124-126 ° C for 1 hour. At this temperature, the distillation continues until a refractive index of 1.5940 is reached. A vacuum is then created and under reduced pressure the distillation continues until a refractive index of 1,600 is reached. In the first example the yield is about 83% and in the second example the yield is about 78%.

Table 1

Example 1 2 not according to the invention of the invention Phenol 2130,7 g 1770,6 g Paraformaldehyde 91% 865,3 g 984,3 g p-butanol - 279,6 g Zinc acetate dihydrate 1.0 g 1.5 g

2) Preparation of phenolic resin solutions

Following the instructions given above, the solutions listed in Table II are obtained. Trade names are denoted by (H).

Table II

Example 1A 1C 1C 1D not according to the invention Phenolic resin 1 67.5% 67.5% 67.5% 67.5% DBE (H) ^A > 19.0% 24,5% 27.0% 32,0% Forbiol 102 (H) ^B) 13.0% 7.5% 5.0% Silan 0.5% 0,5%, 0,5%, 0.5% Viscosity (mPa.s) two phases 659 617 561 Example 2A 2B 2C 2D 2E 2F 2G 2H of the invention Phenolic resin 2 67,% 67.5% 67.5% 67.5% 67.5% 67.5% 67.5% 67.5% DBE (H) ^A > 19.0% 24,5% 27.0% 32,0% Butylglyl colacetate 32,0% Ethylene glycol diacetate 32,0%

Dipropylene glycol dimethyl ether 32,0% Propylene carbonate 32,0% Forbiol 102 (H) ^B) 13.0% 7.5% 5.0% Silan 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% Viscosity (mPa.s) 289 280 264 241 217 297 271 338

^A) DBE, dibasic ester, dimethyl ester mixture of dicarboxylic acids with 4 to 6 carbon atoms (Du Pont) ^c) Forbiol 102, butyric acid tartaric acid (Arizona Chemical)

The phenolic resin 1A solution was removed after cooling to room temperature in two phases and separated without further testing. The viscosity of the IBID phenolic resin solutions is far beyond the technically advantageous application tables (up to about 400 mPa.s).

3) Preparation of polyisocyanate solutions

As component II of the polyurethane binder, the solutions listed in Table III are obtained.

Example FOR SO Sun. of the invention Diphenylmethane diisocyanate (MD1) 80% 80% 80% Forbiol 102 (H) 19.8% 10% Forbiol 152 (H) ^c) 19.8% Solvesso 100 (H) ^d) 9,8% Acid chloride 0.2% 0.2% 0.2%

^c) Forbiol 152, tallic acid octyl / decyl ester (Arizona Chemical) ^d) Solvesso 100, aromatic hydrocarbon mixture (Exxon)

Preparation and testing of a molding material / binder

To obtain a mixture of molding material / binder is as follows:

To 100 wt. h. Quartz sand H 32 (Quartz, Frechen) were added successively 0.5 wt. pp. from one phenolic resin solution given in Table II and 0.8 wt. pp. of one polyisocyanate solution from those listed in Table III and vigorously stirred in a laboratory mixer. From this mixture samples were obtained according to DIN 52401, which hardened by gassing with triethylamine for 10 s at 4 bar pressure, and then purging for 10 s with air).

The flexural strength of the specimens is determined by the GF method. In this case, the flexural strength of the specimens is determined immediately after their receipt (instantaneous strength) and after 1, 2 and 24 h.

The results are given in Table IV.

Table IV

Experience 1 2 3 4 5 6 7 8 9 10 11 12 13 Component 1 IB 1C 1D 2A 2B 2C 2D 2E 2F 2G 2H 2D 2D Component 2 FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR SO Sun. not according to the invention of the invention Quality (N / cm ² ) Instant 105 120 140 205 235 225 205 225 200 230 180 190 210 1 h 380 355 390 555 575 565 580 560 555 530 430 580 500 2 h 400 405 400 555 575 565 580 560 570 590 440 585 530 24 h 555 540 530 590 630 610 590 570 570 600 550 590 570

Table III establishes the following:

- the binders obtained with the previously known phenolic resins (Examples 1-3) show a substantially limited initial strength compared to the binders according to the present invention (experiments - Examples 4-13). Also, the strength gain is clearly emphasized at a slower pace;

- the strengths, especially the instantaneous strengths, of all the binders according to the present invention (Experiments 4-13) are within the accuracy of the test methods used. No relationship was found between the fatty acid ester / polar solvent ratio;

Table V

- to the extent that a fatty butyl ester is appropriate, the octyl octyl / decyl ester for the binders according to the present invention is also appropriate (Experiments 7 and 12);

- combination with aromatic solvents (Experiments 7 and 13) is also possible.

5) Monitoring of the occurrence of smoke

Test gates were placed in an oven at 650 ° C for 1 min. After subtraction, smoke appears on a dark background and is rated at 10 (very strong) - 1 means barely observed.

The results obtained are given in Table V.

Foundry hearts from experience (Table IV) 4 5 6 7 8 9 10 11 12 Component 1 2A 2B 2C 2D 2E 2F 2G 2H 2D Component 2 FOR FOR FOR FOR FOR FOR FOR FOR SO Rating 10 8 8 5 5 5 5 5 5

It can be seen from Table V that the appearance of smoke attenuates when fatty acid esters decrease in favor of solvents with a rich oxygen content.

Casting experiments with casting hearts obtained from mixtures described in Experiments 4 and 7 show the same results as those given above.

Claims (8)

Claims A binder comprising one phenolic resin component and one polyisocyanate component, characterized in that the phenolic resin component comprises an alkoxy-substituted phenolic resin in which less than 25 mol% of the phenolic hydroxyl groups are esterified with primary or secondary aliphatic mono-alcohols having 1 to 10 carbon atoms and in which the amount of solvent in the phenolic component is at most 40% by weight. The binder according to claim 1, wherein the phenolic resin component comprises a polar, organic solvent, the polar, organic solvent being selected from dicarboxylic ester, glycol ether, glycol diester, glycol dieter, cyclic ketones, cyclic esters and cyclic esters. The binder according to claim 2, wherein the phenolic resin component comprises a fatty acid ester. The binder according to claim 3, wherein the alcohol-derived fatty acid ester residue has from 1 to 12 carbon atoms. 5. Forming mixture comprising aggregates and one active binder up to 5 15% by weight according to the weight of the aggregates of the binder according to claims 1 to 4. 6. A method of producing casting molds, comprising: a) mixing aggregates with a binder according to one of claims 1 to 4 in an amount up to 15% by weight. by the quantity of aggregates; b) filling the mold with the casting mixture obtained in (a); c) solidifying the foundry mixture in the form to obtain a stable stand-alone mold; d) finally removing the mold foundry mixture from point (c) from the mold and carrying out further curing to obtain solid, solid and hardened molding materials. The method of claim 6, wherein the casting mixture is cured by treatment with an amine. 8. A metal casting method comprising: (a) producing molding materials according to claim 6 or 7; b) casting metal in liquid form (condition) in or around the corresponding mold; c) cooling and hardening of the metal; and d) finally the separation of the cast article.