USE OF A COMPOSITION AS A BINDER COMPONENT FOR PRODUCING FEEDER ELEMENTS ACCORDING TO THE COLD BOX PROCESS, CORRESPONDING METHOD, AND FEEDER ELEMENTS

Abstract

A description is given of a use of a composition comprising an ortho-fused phenolic resole in an amount of up to 60 wt %; as first solvent for the ortho-fused phenolic resole, one or more compounds selected from the group consisting of alkyl silicates, alkyl silicate oligomers and mixtures thereof, the total amount of these compounds being greater than 30 wt %; optionally one or more further solvents for the ortho-fused phenolic resole; optionally one or more further additives; the weight percentages being based on the total amount of the composition, as a binder component for producing feeder elements by the cold box process. A description is also given of the use of a two-component binder system for producing feeder elements by the cold box process, and of a method for producing a feeder element for the foundry industry, and also of a feeder element.

Claims

1. Method for producing feeder elements by the cold box process, comprising: using a composition comprising an ortho-fused phenolic resole in an amount of up to 60 wt %, as first solvent for the ortho-fused phenolic resole, one or more compounds selected from the group consisting of alkyl silicates, alkyl silicate oligomers and mixtures thereof, the total amount of these compounds being greater than 30 wt %, optionally one or more further solvents for the ortho-fused phenolic resole, optionally one or more further additives, the weight percentages being based on the total amount of the composition, as a binder component for producing feeder elements by the cold box process.

2. The method as claimed in claim 1, wherein the composition comprises as first solvent for the ortho-fused phenolic resole, one or more compounds selected from the group consisting of alkyl silicates, alkyl silicate oligomers and mixtures thereof, the total amount of these compounds being greater than 30 wt %, optionally one or more further solvents for the ortho-fused phenolic resole, and optionally one or more further additives, the ratio by mass of the total amount of first solvent to the total amount of further solvents and further additives being at least greater than 1, preferably at least greater than 2.

3. The method as claimed in claim 1, wherein the composition comprises as first solvent for the ortho-fused phenolic resole, one or more alkyl silicates, the total amount of these alkyl silicates being being greater than than 30 wt % and preferably being 35 wt % or more, based on the total amount of the composition, and preferably as first solvent for the ortho-fused phenolic resole, one or more tetraalkyl silicates, the total amount of these tetraalkyl silicates being greater than 30 wt % and preferably being 35 wt % or more, based on the total amount of the composition.

4. The method as claimed in claim 1, wherein the composition comprises as first solvent for the ortho-fused phenolic resole, tetraethyl silicates, the total amount of these tetraethyl silicates being greater than 30 wt % and preferably being at least 35 wt % or more, based on the total amount of the composition.

5. The method as claimed in claim 1, wherein the composition comprises the ortho-fused phenolic resole in an amount of 40 to 60 wt %, preferably 50 to 60 wt %, based on the total amount of the composition.

6. The method as claimed in claim 1, wherein the composition comprises one or more further solvents for the ortho-fused phenolic resole, selected from the group consisting of mixtures of dialkyl esters of C.sub.2 to C.sub.6 dicarboxylic acids, preferably of dimethyl esters of C.sub.4 to C.sub.6 dicarboxylic acids, monoesters of fatty acids with a carbon chain of 12 or more C atoms, preferably alkyl monoesters, more preferably methyl monoesters and/or butyl monoesters, and propylene carbonate.

7. The method as claimed in claim 1, wherein the composition comprises a total amount of solvents for the ortho-fused phenolic resole in the range from 40 to 60 wt %, preferably a total amount in the range from 40 to 50 wt %, based on the total amount of the composition.

8. The method as claimed in claim 1, wherein the composition comprises one or more further additives, selected from the group consisting of acyl chlorides, methanesulfonic acid, aromatic hydrocarbons, adhesion promoters, preferably silanes, more preferably selected from the group consisting of aminosilanes, epoxysilanes, mercaptosilanes and ureidosilanes, and esters of phosphoric acid.

9. A method of producing feeder elements by the cold box process, comprising: using a two-component binder system consisting of a composition as defined in any of the preceding claims, as phenolic resin component, and, spatially separate therefrom, a polyisocyanate component for producing feeder elements by the cold box process.

10. The method as claimed in claim 1, wherein the feeder elements comprise one or more of the following materials (a), (b), (c) and (d): (a) one or more refractory fillers, the one or at least one of the two or more refractory fillers being selected from the group consisting of chamotte, hollow-sphere corundum, spheres of flyashes, rice husk ashes, expanded glasses, foamed glasses, expanded perlites, core-shell particles and refractory lightweight fillers, another of the two or more refractory fillers preferably being sand, more preferably quartz sand, the one or at least one of the two or more refractory fillers preferably being selected from the group consisting of rice husk ashes, expanded glasses, foamed glasses, expanded perlites, core-shell particles and refractory lightweight fillers, the one or at least one of the two or more refractory fillers being more preferably selected from the group consisting of core-shell particles and refractory lightweight fillers, preferably refractory lightweight fillers having a bulk density in the range from 10 to 600 g/L, more preferably refractory lightweight fillers having a bulk density in the range from 50 to 300 g/L, (b) one or more metallic or semimetallic materials, the one or at least one of the two or more metallic or semimetallic materials being preferably selected from the group consisting of aluminum, magnesium and silicon, (c) one or more oxidants, the one or at least one of the two or more oxidants being preferably selected from the group consisting of iron oxides, manganese dioxide and nitrates, and (d) one or more ignitors, the one or at least one of the two or more ignitors being selected from the group consisting of barium sulfate, spodumene, cordierite, andalusite, sillimanite, kyanite, nepheline, feldspar, one or more phyllosilicates.

11. The method as claimed in claim 10, wherein the feeder element (i) comprises one or more metallic or semimetallic materials, the one or at least one of the two or more metallic or semimetallic materials being preferably selected from the group consisting of aluminum, magnesium and silicon and the bulk density of a mixture of all of the solids used for producing the feeder element being 2 g/cm.sup.3 or less, preferably 1.6 g/cm.sup.3 or less, more preferably 1.2 g/cm.sup.3 or less and very preferably in the range from 1 to 2 g/cm.sup.3, or (ii) does not comprise aluminum, magnesium and silicon, and preferably does not comprise metallic or semimetallic materials, and the bulk density of a mixture of all of the solids used for producing the feeder element being 1 g/cm.sup.3 or less, preferably 0.8 g/cm.sup.3 or less, more preferably 0.7 g/cm.sup.3 or less and very preferably in the range from 0.4 to 1 g/cm.sup.3.

12. The method according to claim 1, further comprising: producing or providing a molding mixture for a feeder element, producing or providing the components of a two-component binder system consisting of: a composition as defined in any of the preceding claims, as phenolic resin component, and, spatially separate therefrom, a polyisocyanate component, mixing the molding mixture produced or provided with the produced or provided components of the two-component binder system, molding the resulting mixture to give an uncured feeder element, and curing the feeder element according to the cold box process.

13. The method as claimed in claim 12, wherein the molding mixture comprises one or more of the following materials (a) one or more refractory fillers, the one or at least one of the two or more refractory fillers being selected from the group consisting of chamotte, hollow-sphere corundum, spheres of flyashes, rice husk ashes, expanded glasses, foamed glasses, expanded perlites, core-shell particles and refractory lightweight fillers, another of the two or more refractory fillers preferably being sand, more preferably quartz sand, the one or at least one of the two or more refractory fillers preferably being selected from the group consisting of rice husk ashes, expanded glasses, foamed glasses, expanded perlites, core-shell particles and refractory lightweight fillers, the one or at least one of the two or more refractory fillers being more preferably selected from the group consisting of core-shell particles and refractory lightweight fillers, preferably refractory lightweight fillers having a bulk density in the range from 10 to 600 g/L, more preferably refractory lightweight fillers having a bulk density in the range from 50 to 300 g/L, (b) one or more metallic or semimetallic materials, the one or at least one of the two or more metallic or semimetallic materials being preferably selected from the group consisting of aluminum, magnesium and silicon, (c) one or more oxidants, the one or at least one of the two or more oxidants being preferably selected from the group consisting of iron oxides, manganese dioxide and nitrates, and (d) one or more ignitors, the one or at least one of the two or more ignitors being selected from the group consisting of barium sulfate, spodumene, cordierite, andalusite, sillimanite, kyanite, nepheline, feldspar, one or more phyllosilicates.

14. The method as claimed in claim 13, wherein the molding mixture (i) comprises one or more metallic or semimetallic materials, the one or at least one of the two or more metallic or semimetallic materials being preferably selected from the group consisting of aluminum, magnesium and silicon and the bulk density of the molding mixture being 2 g/cm.sup.3 or less, preferably 1.6 g/cm.sup.3 or less, more preferably 1.2 g/cm.sup.3 or less and very preferably in the range from 1 to 2 g/cm.sup.3, or (ii) does not comprise aluminum, magnesium and silicon, and preferably does not comprise metallic or semimetallic materials, and the bulk density of the molding mixture being 1 g/cm.sup.3 or less, preferably 0.8 g/cm.sup.3 or less, more preferably 0.7 g/cm.sup.3 or less and very preferably in the range from 0.6 to 1 g/cm.sup.3.

15. A feeder element producible by a method as claimed in claim 13, wherein the feeder element (i) comprises metallic or semimetallic materials (b), preferably additionally the materials (c) and/or (d), and possesses a density in the range from 1.0 to 2.0 g/cm.sup.3, preferably a density in the range from 1.0 to 1.6 g/cm.sup.3, more preferably a density in the range from 1.0 to 1.2 g/cm.sup.3, or (ii) comprises one or more refractory fillers (a) and possesses a density in the range from 0.6 to 1.0 g/cm.sup.3, preferably a density in the range from 0.6 to 0.8 g/cm.sup.3, more preferably a density in the range from 0.6 to 0.7 g/cm.sup.3.

16. The method according to claim 9, further comprising: producing or providing a molding mixture for a feeder element, producing or providing a binder component composition and also a polyisocyanate component, as spatially separate components of a two-component binder system, wherein the binder component composition comprises: an ortho-fused phenolic resole in an amount of up to 60 wt %, as first solvent for the ortho-fused phenolic resole, one or more compounds selected from the group consisting of alkyl silicates, alkyl silicate oligomers and mixtures thereof, the total amount of these compounds being greater than 30 wt %, optionally one or more further solvents for the ortho-fused phenolic resole, optionally one or more further additives, the weight percentages being based on the total amount of the binder component, mixing the molding mixture produced or provided with the produced or provided components of the two-component binder system, molding the resulting mixture to give an uncured feeder element, and curing the feeder element according to the cold box process.

17. The method as claimed in claim 16, wherein the molding mixture comprises one or more of the following materials (a) one or more refractory fillers, the one or at least one of the two or more refractory fillers being selected from the group consisting of chamotte, hollow-sphere corundum, spheres of flyashes, rice husk ashes, expanded glasses, foamed glasses, expanded perlites, core-shell particles and refractory lightweight fillers, another of the two or more refractory fillers preferably being sand, more preferably quartz sand, the one or at least one of the two or more refractory fillers preferably being selected from the group consisting of rice husk ashes, expanded glasses, foamed glasses, expanded perlites, core-shell particles and refractory lightweight fillers, the one or at least one of the two or more refractory fillers being more preferably selected from the group consisting of core-shell particles and refractory lightweight fillers, preferably refractory lightweight fillers having a bulk density in the range from 10 to 600 g/L, more preferably refractory lightweight fillers having a bulk density in the range from 50 to 300 g/L, (b) one or more metallic or semimetallic materials, the one or at least one of the two or more metallic or semimetallic materials being preferably selected from the group consisting of aluminum, magnesium and silicon, (c) one or more oxidants, the one or at least one of the two or more oxidants being preferably selected from the group consisting of iron oxides, manganese dioxide and nitrates, and (d) one or more ignitors, the one or at least one of the two or more ignitors being selected from the group consisting of barium sulfate, spodumene, cordierite, andalusite, sillimanite, kyanite, nepheline, feldspar, one or more phyllosilicates.

18. The method as claimed in claim 16, wherein the molding mixture (i) comprises one or more metallic or semimetallic materials, the one or at least one of the two or more metallic or semimetallic materials being preferably selected from the group consisting of aluminum, magnesium and silicon and the bulk density of the molding mixture being 2 g/cm.sup.3 or less, preferably 1.6 g/cm.sup.3 or less, more preferably 1.2 g/cm.sup.3 or less and very preferably in the range from 1 to 2 g/cm.sup.3, or (ii) does not comprise aluminum, magnesium and silicon, and preferably does not comprise metallic or semimetallic materials, and the bulk density of the molding mixture being 1 g/cm.sup.3 or less, preferably 0.8 g/cm.sup.3 or less, more preferably 0.7 g/cm.sup.3 or less and very preferably in the range from 0.6 to 1 g/cm.sup.3.

19. A feeder element producible by a method as claimed in claim 16, wherein the feeder element (i) comprises metallic or semimetallic materials (b), preferably additionally the materials (c) and/or (d), and possesses a density in the range from 1.0 to 2.0 g/cm.sup.3, preferably a density in the range from 1.0 to 1.6 g/cm.sup.3, more preferably a density in the range from 1.0 to 1.2 g/cm.sup.3, or (ii) comprises one or more refractory fillers (a) and possesses a density in the range from 0.6 to 1.0 g/cm.sup.3, preferably a density in the range from 0.6 to 0.8 g/cm.sup.3, more preferably a density in the range from 0.6 to 0.7 g/cm.sup.3.

Description

DESCRIPTION OF THE FIGURES

[0177] FIG. 1: burning of a feeder element produced according to the feeder formulation Standard in table 1 (see below).

[0178] FIG. 2: burning of a feeder element produced according to the feeder formulation HA 2 in table 1 (see below).

EXAMPLES

[0179] The examples below are intended to elucidate the invention without limiting it.

[0180] The abbreviation pbw used in the examples denotes parts by weight (parts by mass).

[0181] Concerning the measurement method used for the flexural strength after 24 hours (flexural strength 24 h):

[0182] The flexural strength was determined in a method based on German VDG standard P 73, method A (type of mixer used: BOSCH Profi 67, processing at room temperature and ambient humidity, production by ramming, capture of test values after 1 h and after 24 h, triplicate determination in each case) using the PFG strength testing apparatus with low-pressure manometer N (with motor drive).

Examples 1 to 3 were Carried Out in Close Alignment with Examples 1 to 3 of Document EP 1 057 554 B1

Example 1: Preparation of a Phenolic Resin (Precondensate)

[0183] A reaction vessel equipped with condenser, thermometer and stirrer was charged with [0184] 385.0 pbw of phenol (pure) [0185] 176.0 pbw of paraformaldehyde (91 percent form; as formaldehyde source) [0186] and [0187] 0.11 pbw of zinc acetate decahydrate.

[0188] The condenser was set to reflux. The temperature was raised continuously over the course of an hour to bring it to 105 C. and was maintained at this temperature for two to three hours until a refractive index of 1.550 was reached.

[0189] The condenser was then changed over to atmospheric distillation and the temperature was increased over the course of an hour to 125-126 C., until a refractive index of about 1.593 was reached. This was followed by vacuum distillation until the refractive index was 1.612. The yield amounted to around 82-83% of the raw materials used.

Example 2: Preparation of Cold Box Phenolic Resin Solutions

[0190] Resin solutions for the cold box process were prepared from the phenolic resin (precondensate) according to example 1, after attainment of the target refractive index value, these solutions having the compositions as indicated below:

Cold box resin solutions gas resins EX-1 to EX-5
Gas resin EX-1 [0191] 55 pbw of phenolic resin (precondensate) [0192] 30 pbw of tetraethyl silicate [0193] 14.7 pbw of DBE (trade name Dibasic Ester from DuPont) [0194] 0.3 pbw of aminosilane or amidosilane [0195] Note: gas resin EX-1 corresponds to resin solution HA 1 from example 2 of EP 1 057 554 B1
Gas resin EX-2 [0196] 55 pbw of phenolic resin (precondensate) [0197] 35 pbw of tetraethyl silicate [0198] 9.7 pbw of DBE (trade name Dibasic Ester from DuPont) [0199] 0.3 pbw of aminosilane or amidosilane [0200] Note: gas resin EX-2 corresponds to resin solution HA 2 from example 2 of EP 1 057 554 B1
Gas resin EX-3 [0201] 55 pbw of phenolic resin (precondensate) [0202] 15 pbw of tetraethyl silicate [0203] 29.7 pbw of DBE (trade name Dibasic Ester from DuPont) [0204] 0.3 pbw of aminosilane or amidosilane [0205] Note: gas resin EX-3 corresponds to resin solution HA 3 from example 2 of EP 1 057 554 B1
Gas resin EX-4 [0206] 55 pbw of phenolic resin (precondensate) [0207] 1 pbw of tetraethyl silicate [0208] 43.7 pbw of DBE (trade name Dibasic Ester from DuPont) [0209] 0.3 pbw of aminosilane or amidosilane [0210] Note: gas resin EX-4 corresponds to resin solution HA 4 from example 2 of EP 1 057 554 B1
Gas resin EX-5 [0211] 55 pbw of phenolic resin (precondensate) [0212] 5 pbw of tetraethyl silicate [0213] 44.7 pbw of DBE (trade name Dibasic Ester from DuPont) [0214] 0.3 pbw of aminosilane or amidosilane [0215] Note: gas resin EX-5 corresponds to resin solution HA 5 from example 2 of EP 1 057 554 B1
Conventionally for comparison: GAS RESIN EX-6 [0216] 54.2 pbw of phenolic resin (precondensate) [0217] 24.0 pbw of DBE [0218] 21.5 pbw of RME (rapeseed oil methyl ester) [0219] 0.3 pbw of aminosilane or amidosilane

Example 3: Preparation of Polyisocyanate Solutions for the Cold Box Process

[0220] Additionally, polyisocyanate solutions (ACTIVATOR EY-1 and ACTIVATOR EY-2) were prepared for the cold box process, these solutions having the compositions indicated below:

ACTIVATOR EY-1

[0221] 85.0 pbw of diphenylmethane diisocyanate [0222] 14.7 pbw of RME (rapeseed oil methyl ester) [0223] 0.3 pbw of acyl chloride (additive for extending the sand life)

ACTIVATOR E-Y2

[0224] 80.0 pbw of diphenylmethane diisocyanate [0225] 9.4 pbw of tetraethyl silicate [0226] 9.0 pbw of dioctyl adipate [0227] 1.4 pbw of additive EZ-1 from PCT/EP2012/072705 (additive for extending the sand life)

Example 4: Production of Cold-Box-Bound Feeder Test Specimens

[0228] The molding sand mixtures listed in table 1 below were produced and mixed with the above-specified phenolic resin solutions and polyisocyanate solutions (cf. examples 2 and 3) to give the resulting feeder formulations standard, HA1, HA2, HA3, HA4 and HA5.

TABLE-US-00001 TABLE 1 Feeder formulations of the cold-box-bound feeder test specimens Feeder formulation Standard HA1 HA2 HA3 HA4 HA5 Molding Spray-atomized aluminum 26 26 26 26 26 26 sand powder (pbw) mixtures Cordierite (pbw) 3 3 3 3 3 3 Iron oxide (pbw) 9 9 9 9 9 9 Potassium nitrate (pbw) 17 17 17 17 17 17 Chamotte (pbw) 18 18 18 18 18 18 Core-shell particles (pbw) 27 27 27 27 27 27 Activator ACTIVATOR EY-1 (pbw) 4.5 ACTIVATOR EY-2 (pbw) 4.5 4.5 4.5 4.5 4.5 Gas resin GAS RESIN EX-6 (pbw) 4.5 GAS RESIN EX-1 (pbw) 4.5 GAS RESIN EX-2 (pbw) 4.5 GAS RESIN EX-3 (pbw) 4.5 GAS RESIN EX-4 (pbw) 4.5 GAS RESIN EX-5 (pbw) 4.5

[0229] Subsequently, the flexural strengths 24 h of the feeder test specimens produced in accordance with the feeder formulations of table 1 (correspondingly in each case: standard, HA1, HA2, HA3, HA4 and HA5; cf. table 2) were determined by the GF method. In the production of the feeder test specimens and the testing thereof for their flexural strengths (regarding the method, see above), the protocols of the VDG fact sheet P 73 of February 1996 were observed. The results of the testing are set out in table 2. The values for the flexural strengths 24 h of the feeder test specimens produced (corresponding in each case to the feeder formulation used: S-standard, S-HA1, S-HA2, S-HA3, S-HA4 and S-HA5; cf. table 2) correspond to average values from two triplicate determinations. The target value of at least 350 is additionally entered in table 2, and corresponds to a value, customarily required in practice, for flexural strengths of a test specimen for exothermic feeder elements.

TABLE-US-00002 TABLE 2 Measurement values for the flexural strengths 24 h as per VDG fact sheet P 73 Feeder test specimen Target value S-standard S-HA1 S-HA2 S-HA3 S-HA4 S-HA5 Flexural strength at least 350 370 340 380 250 270 300 24 h [N/cm.sup.2]

[0230] Surprisingly, therefore, HA 2 (comprising GAS RESIN EX-2 with a fraction of 35 pbw of tetraethyl silicate) is the only feeder formulation according table 1 for producing an exothermic feeder element (see correspondingly S-HA2 in table 2) that leads to a flexural strength (elasticity) on the part of the test specimens that lies above the target value. Another reason why this finding is surprising is that according to table 2a of document EP 1 057 554 B1, cores (test specimens) produced using resin solution HA 1 (the formulation is identical to that of gas resin EX-1) gave the highest flexural strengths 24 h.

[0231] It is surprising, moreover, that the feeder formulations HA 1 and HA 3 to HA 5 do not lead to reasonable feeder flexural strengths that are acceptable in practice (minimum flexural strength requirement of at least 350 N/cm.sup.2; see target value in table 2), whereas according to EP 1 057 554 B1, table 2a, all of the resin solutions HA 1 to HA 5 stated therein (the formulations of which are each identical to those of gas resin EX-1 to gas resin EX-5) produced test specimens having sufficient flexural strengths for cores.

Example 5: Emissions Test (Reducing the Emission of CO.SUB.2.)

[0232] When using a feeder according to formulation HA 2, it was possible, in comparison to a feeder according to formulation standard (cf. example 4, table 1), to ascertain a lowering by 2% of the emission values in the form of CO.sub.2.

[0233] On burning of the feeder HA 2 (cf. FIG. 2), it was possible, moreover, to see a reduced evolution of fumes by comparison with the standard feeder (cf. FIG. 1).

[0234] Examples 4 and 5 above relate to exothermic feeders and feeder formulations for producing exothermic feeders, respectively. In studies designed correspondingly for insulating feeders and feeder formulas for producing insulating feeders, respectively, GAS RESIN EX-2, with a tetraethyl silicate fraction of 35 pbw, was likewise found to be the binder component which led to the best results in relation to flexural strength and emission reduction.