| abstract |
The invention relates to a water based binder for use in a slurry for investment casting. The binder includes a mixture of a colloidal silica sol and at least one latex polymer. The latex polymer is preferably an acrylic latex or a styrene butadiene polymer (or a combination of these) which reduces the processing time between dips during shell mold making for investment casting. The latex polymer further lowers a critical concentration point or gelation point of the colloidal silica sol. The binder may be used as a primary binder or a backup binder in the shell mold making process. To make the slurry, the binder is combined with at least one refractory powder, preferably a refractory powder selected from the group of: aluminosilicates, fused silica, quartz silica, alumina, zircon, and zirconia. |