U.S. Pat. No. 2,343,972 describes resins that are obtained by reaction of furfuryl alcohol and formaldehyde with heating in the presence of an acid such as lactic acid, formic acid or chloroacetic acid. Concrete information on the properties that are important for binders in the no-bake 5 process is not given in U.S. Pat. No. 2,343,972. 

U.S. Pat. No. 5,741,914 (and correspondingly U.S. Pat. No. 5,849,858) describes resins as binders for producing composites, which are obtained by reacting furfuryl alcohol with an excess of formaldehyde in the presence of an acid with a pKa value above about 4, wherein the molar ratio of furfuryl alcohol to formaldehyde is at least 1:2. Similar resins are disclosed in U.S. Pat. No. 5,486,557. 

DE 21 26 800 (and correspondingly CA 1 200 336) describes a method for producing a composite object and suitable binders therefore, wherein the binders are high› viscosity resin-like condensation products based on furan› formaldehyde, which are diluted with water. 

U.S. Pat. No. 3,816,375 (and correspondingly DE 23 02 629) describes partially prepolymerised furfuryl alcohol› aldehyde binders, wherein the aldehyde is formaldehyde and/or furfural, which are used there for forming composite materials. When the material selected for the composite material is glass fibre, according to U.S. Pat. No. 3,816,375 preferably a prepolymerised high-viscosity furfuryl alcohol› aldehyde binder is used, which is diluted with furfural. A similar system is disclosed in U.S. Pat. No. 3,594,345 (and correspondingly DE 19 27 776). 

U.S. Pat. No. 2,874,148 discloses furfuryl alcohol-form- aldehyde resins that are produced by reacting furfuryl alco› hol with formaldehyde in the presence of sulphuric acid. The physical properties of the resins obtained according to U.S. Pat. No. 2,874,148 are very dependent on the other particu› lar reaction conditions. 

Usually a mixture according to the invention for use as binder in the no-bake process does not comprise an acid that has a pKa value below 2 at 25° C., and preferably does not comprise an acid that has a pKa value below 2.5 at 25° C. If in exceptional cases such acids are used, their maximum total amount is preferably less than 5 wt. %, relative to the total weight of the mixture. This applies to all mixtures according to the invention described below. 

Usually a mixture according to the invention for use as binder in the no-bake process does not comprise any refrac- tory granular materials. If in exceptional cases refractory granular materials are used in the mixture, their maximum total amount is preferably less than 5 wt. %, relative to the total amount of the mixture. This applies to all mixtures according to the invention described below. 

Usually a mixture according to the invention is a homo› geneous solution; this applies to all preferred mixtures according to the invention described below. 

Preferably a mixture according to the invention contains less than 5 wt. % of monomeric furfural, preferably less than 3 wt. %, more preferably less than 1 wt. % of monomeric furfural. 

Preferably the mixtures according to the invention contain less than 3 wt. % of polyvinyl acetate, preferably less than 1 wt. %, more preferably they are free from polyvinyl acetate. 

Preferably a mixture according to the invention contains less than 5 wt. % of monomeric furfural and less than 3 wt. % of polyvinyl acetate. 

Preferably a mixture according to the invention contains less than 1 wt. % of monomeric furfural and less than 1 wt. % of polyvinyl acetate. 

Preferably the mixtures according to the invention com› prise, as part of constituent (b-1), the compound 2,5-bis (hydroxymethyl)furan (BHMF), preferably in an amount of at least 2 wt. %, more preferably in an amount from 5 to 80 wt. %, particularly preferably in an amount from 10 to 70 wt. %, in particular in an amount from 20 to 60 wt. %, in each case relative to the total weight of constituent (b-1). 

Preferably the mixtures according to the invention com› prise, in constituent (b-1 ), 2,5-bis(hydroxymethyl)furan (BHMF) in an amount of at least 1 wt. %, more preferably in an amount from 5 to 40 wt. %, particularly preferably in an amount from 10 to 35 wt. %, quite particularly preferably in an amount from 15 to 30 wt. %, relative to the total weight of a mixture according to the invention. 

Preferably a mixture according to the invention comprises monomeric furfuryl alcohol (constituent (a)) and 2,5-bis (hydroxymethyl)furan (BHMF) ( as part of constituent (b-1)) in a weight ratio in the range from 3:1 to 1:3, preferably in the range from 2:1 to 1:2, more preferably in the range from 3:2 to 2:3, particularly preferably in the range from 5:4 to 4:5. 

In constituent (b-1) of a mixture according to the inven› tion, the proportion of "furan ring units" can be determined from the furan ring, for example by $^{13}$C-NMR. 

For the case when nitrogen-containing components are present in constituent (b-2), they can be detected from the nitrogen itself. In the case of a phenolic compound as component in constituent (b-2) differentiation is also pos› sible based on the phenolic compound (for example deter› mination of the residual monomer content, GC-MS analy- sis). 

Other suitable analytical methods are $^{15}$N-NMR or $^{13}$C- NMR. 

The proportion of "furan ring" units can be determined by $^{13}$C-NMR. The proportion of "furan ring" units, calculated as furfuryl alcohol (C5H6O2), in the reaction product (b-1) from formaldehyde with furfuryl alcohol and optionally further constituents is preferably in the range from 60 to 96 wt. %, preferably in the range from 70 to 95 wt. %, more preferably in the range from 75 to 90 wt.%, and particularly preferably in the range from 75 to 85 wt. %, in each case relative to the total weight of constituent (b-1). 

In constituent (b-2), the other compound(s) of the reaction product with formaldehyde are preferably selected from the group consisting of organic compounds that have one or a plurality of H$_{2}$N groups and/or one or a plurality of HN groups, and phenolic compounds. 

The particularly preferred organic compound that has one or a plurality of H$_{2}$N groups is urea. 

For this, the phenolic compound(s) can be reacted under acidic conditions with furfuryl alcohol and formaldehyde directly or with a furfuryl alcohol/formaldehyde pre-con› densate. 

The phenolic compounds are preferably phenolic com› pounds with 6 to 25 carbon atoms and/or one, two, three or four hydroxyl groups bound directly to an aromatic ring, preferably selected from the group consisting of phenol, optionally Cl-C4-alkyl-mono- or -disubstituted dihydroxy› benzenes, trihydroxybenzenes, methylphenols and bisphe› nols, particularly preferably selected from the group con- sisting of phenol, o-dihydroxybenzene, m-dihydroxybenzene (resorcinol), p-dihydroxybenzene, 5-methy lresorcinol, 5-ethy lresorcinol, 2, 5-dimethy lresorci- nol, 4,5-dimethylresorcinol, 1,2,3-trihydroxybenzene, 1,3,5- 

