wherein the percentages by weight are relative to the total weight of the mixture. 

5. The binder mixture for a no-bake process according to claim 1, wherein the content of free formaldehyde is at most 0.4 wt. %, wherein the percentages by weight are relative to the total weight of the mixture. 

6. The binder mixture for a no-bake process according to claim 1, wherein the ammonia content is at most 1 wt. %, wherein the percentages by weight are relative to the total weight of the mixture. 

7. The binder mixture for a no-bake process according to claim 1, wherein the total nitrogen content is at most 4 wt. %, wherein the percentages by weight are relative to the total weight of the mixture. 

8. The binder mixture for a no-bake process according to claim 1, wherein constituent (b-1) comprises 2,5-bis(hy› droxymethyl)furan (BHMF) in an amount of at least 1 wt.%, relative to the total weight of a mixture according to the invention. 

9. The binder mixture for a no-bake process according to claim 8, wherein the weight ratio of constituent (a) and 2,5-bis(hydroxymethyl)furan (BHMF) of constituent (b-1) is in the range from 3:1 to 1:3. 

11. The binder mixture for a no-bake process according to claim 1, wherein the ratio of weight average molecular weight Mw to number average molecular weight Mn of constituent (b-1) is in the range from 5:1 to 9:8. 

12. The binder mixture for a no-bake process according to claim 1, additionally comprising as further constituent 

( e) one or a plurality of adhesion promoters selected from the group of silanes, N-aminopropylmethyldiethoxysi› lane, N-aminoethy 1-3-aminopropy ltrimethoxysilane, N-aminoethyl-3-aminopropylmethy ldiethoxysilane and/or N-aminopropyltriethoxysilane, in a total amount ofup to 3 wt.%, 

wherein the percentages by weight are relative to the total weight of the mixture. 

13. The binder mixture for a no-bake process according to claim 1, additionally comprising one or a plurality of further constituents, selected from the group of 

(g) inert organic solubilisers, selected from the group of alcohols R---OH, wherein R denotes a Cl-C4 alkyl residue, 

(h) reaction products of furfuryl alcohol and one or a plurality of aldehydes with 2 or more carbon atoms, 

G) organic compounds that have one or a plurality ofH$_{2}$N groups and/or one or a plurality of HN groups, 

(k) phenolic compounds, with 6 to 25 carbon atoms and/or one, two, three or four hydroxyl groups bound directly to an aromatic ring, 

(m) benzyl alcohol, 

(n) aldehydes with 2 or more carbon atoms selected from the group consisting of acetaldehyde, propionaldehyde, butyraldehyde, acrolein, crotonaldehyde, benzalde- hyde, salicylaldehyde, cinnamaldehyde, glyoxal and mixtures of these aldehydes. 

## 31 

## US 9,993,863 B2 

14. The binder mixture for a no-bake process according to claim 1, wherein the pH of the mixture at 25° C. is in the range from 5 to 9.5. 

15. The binder mixture for a no-bake process according to claim 1, wherein the mixture is a mixture that is stable in storage, which has a storage stability of at least 3 months at 20° C., wherein during the storage period 

5 

the viscosity value of the mixture at 20° C., measured according to DIN 53019-1: 2008-09, increases by at most 80%, and 

10 

the proportion by weight of constituent (a) decreases by at most 10% relative to the initial amount of monomeric furfuryl alcohol at the start of the storage period. 

16. The binder mixture for a no-bake process according to claim 1, further comprising methanol as an inert organic solubiliser. 

15 

17. The binder mixture for a no-bake process according to claim 1, that is produced by a method including the follow› ing step: 

(S-1) reacting a furfuryl alcohol with formaldehyde and optionally further constituents in the presence of one or a plurality of organic acids with a pKa value greater than or equal to 2.5 at 25° C. and/or salts thereof, wherein the molar ratio of the total amount of furfuryl alcohol used to the total amount of formaldehyde used is greater than or equal to 1. 

20 

18. Reaction mixture, comprising 

(i) a mixture according to claim 1; 

(ii) an acid, wherein the acid has a pKa value ofless than 2 at 25° C., 

wherein the reaction mixture comprises a content of free formaldehyde of max. 0.4 wt. %, and 

wherein the percentages by weight are relative to the total weight of the reaction mixture. 

19. Reaction mixture according to claim 18, wherein the reaction mixture comprises no sulphuric acid or comprises sulphuric acid in an amount of max. 1 wt. %, wherein the percentages by weight are relative to the total weight of the reaction mixture minus the total weight of refractory granu- lar materials in the reaction mixture. 

35 

40 

20. Reaction mixture according to claim 18, wherein the acid of component (ii) is selected from the group of organic acids. 

21. Reaction mixture according to claim 1, additionally comprising 

45 

(iii) one or a plurality of refractory granular materials in an amount of 80 wt. % or more relative to the total weight of the reaction mixture. 

22. Reaction mixture according to claim 1, wherein the mixture does not contain sulphur dioxide, a peroxide, or both sulphur dioxide and a peroxide. 

23. Method of preparing a mixture according to claim 1, with the following step: 

(S-1) reaction of furfuryl alcohol with formaldehyde and optionally further constituents in the presence of one or a plurality of organic acids with a pKa value greater than or equal to 2.5 at 25° C. and/or salts thereof wherein the molar ratio of the total amount of furfuryl alcohol used to the total amount of formaldehyde used is greater than or equal to 1. 

55 

60 

24. Method according to claim 23, wherein step (S-1) takes place at a temperature in the range from 90 to 160° C. 

25. Method according to claim 23, with the following further steps: 

(S-2) preheating of the reaction mixture resulting from step (S-I) to a temperature in the range from 40 to 90° C. 

65 

## 32 

