Abstract: A binder composition for making foundry molds, comprising an acid-hardening resin, one or more 5-position-substituted-furfural compounds selected from the group consisting of 5-hydroxymethylfurfural and 5-acetoxymethylfurfural, and one or more compounds selected from the group consisting of urea and derivatives of urea, wherein the content of the 5-position-substituted-furfural compound(s) by percentage is from 1 to 60% by weight of the binder composition. The content of the compound(s) by percentage selected from the group consisting of urea and derivatives of urea is preferably from 0.3 to 10% by weight of the binder composition.

Abstract: A curing agent composition for making foundry molds, comprising 2,6-dihydroxybenzoic acid. In a sand composition for making foundry molds, it is preferable to use simultaneously: an acid-hardening resin which contains both a binder composition for making foundry molds which comprises one or more 5-position-substituted furfural compounds selected from the group consisting of 5-hydroxymethylfurfural and 5-acetoxymethylfurfural, and the curing agent composition for making foundry molds which comprises 2,6-dihydroxybenzoic acid. It is preferable that the content of 2,6-dihydroxybenzoic acid in the curing agent composition is 10 to 80 wt %.

Abstract: Disclosed is a binder composition for mold formation including: one or more 5-position substituted furfural compounds selected from the group consisting of 5-hydroxymethylfurfural and 5-acetoxymethylfurfural; and a furfurylated urea resin. The content of the 5-position substituted furfural compound(s) in the binder composition for mold formation is preferably from 1 to 30% by weight, and the content of the furfurylated urea resin is preferably from 1 to 20% by weight.

Abstract: A curing agent composition for making foundry molds, comprising 2,6-dihydroxybenzoic acid. In a sand composition for making foundry molds, it is preferable to use simultaneously: an acid-hardening resin which contains both a binder composition for making foundry molds which comprises one or more 5-position-substituted furfural compounds selected from the group consisting of 5-hydroxymethylfurfural and 5-acetoxymethylfurfural, and the curing agent composition for making foundry molds which comprises 2,6-dihydroxybenzoic acid. It is preferable that the content of 2,6-dihydroxybenzoic acid in the curing agent composition is 10 to 80 wt %.

Abstract: A binder composition for making foundry molds, comprising an acid-hardening resin, one or more 5-position-substituted-furfural compounds selected from the group consisting of 5-hydroxymethylfurfural and 5-acetoxymethylfurfural, and one or more compounds selected from the group consisting of urea and derivatives of urea, wherein the content of the 5-position-substituted-furfural compound(s) by percentage is from 1 to 60% by weight of the binder composition. The content of the compound(s) by percentage selected from the group consisting of urea and derivatives of urea is preferably from 0.3 to 10% by weight of the binder composition.

Abstract: Disclosed is a binder composition for mold formation including: one or more 5-position substituted furfural compound selected from the group consisting of 5-hydroxymethylfurfural and 5-acetoxymethylfurfural; and a furfurylated urea resin. The content of the 5-position substituted furfural compound(s) in the binder composition for mold formation is preferably from 1 to 30% by weight, and the content of the furfurylated urea resin is preferably from 1 to 20% by weight.

Abstract: A binder composition for self-curing mold formation, comprising at least one condensate (A) selected from furfuryl alcohol condensate and furfuryl alcohol/formaldehyde condensate, and an acid-curable resin (B), wherein about the condensate(s) (A), the presence ratio by mole of its/their furan rings (a) to the total of its/their methylol groups (b), methylene groups (c) and oxymethylene groups (d), a:(b+c+d), is from 1:1.00 to 1:1.08, and the content by percentage of the at least one condensate (A) is from 0.3 to 8.0% by weight.

Abstract: A binder composition for self-curing mold formation, comprising at least one condensate (A) selected from furfuryl alcohol condensate and furfuryl alcohol/formaldehyde condensate, and an acid-curable resin (B), wherein about the condensate(s) (A), the presence ratio by mole of its/their furan rings (a) to the total of its/their methylol groups (b), methylene groups (c) and oxymethylene groups (d), a:(b+c+d), is from 1:1.00 to 1:1.08, and the content by percentage of the at least one condensate (A) is from 0.3 to 8.0% by weight.