Process for the production of foundry cores and molds
AssigneeBayer Aktiengesellschaft
InventorRolf Kubens
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Abstract
Foundry cores and molds are produced from foundry sand and/or other inert fillers, polyhydroxyl compounds, polyisocyanates and tertiary amine catalysts. The precatalyzed mixtures can be stored for long periods of time without any adverse effects on the subsequent processing or core properties when at least 80% by weight of the polyisocyanate used is of the diphenyl alkane series in which the isocyanate groups are sterically hindered solely by substituents in at least one ortho position.
Claims10
In a process for the production of foundry cores and molds wherein a mixture of inert fillers, polyhydroxyl compounds, polyisocyanates and tertiary amines is cured in a mold, the improvement wherein at least 80% by weight of the polyisocyanate component used consists of polyisocyanates of the diphenyl alkane series which solely contain isocyanate groups sterically hindered by substituents in at least one ortho position.
Dependencies are inferred from the claim text.