Foundry Binder System With A Low Formaldehyde Content And Process For Obtaining It
Patent No. EP3530685 (titled "Foundry Binder System With A Low Formaldehyde Content And Process For Obtaining It") was filed by Cavenaghi on Apr 21, 2016. The application was issued on Sep 10, 2025.
Patent Summary
This method produces furan resins with low free formaldehyde content (preferably <0.1% by weight) for use in foundry binder systems, refractory bricks, or refractory masses. The process comprises three primary steps: (a) reacting furfuryl alcohol and formaldehyde using an acid catalyst; (b) heat-treating the resulting condensation polymer with a strong base at 90°C to 115°C; and (c) adding urea. The method specifically excludes the addition of 4,4'-isopropylidenediphenol. The resulting resins are suitable for no-bake foundry processes when mixed with silica sand or other granular substances and an acid hardener (e.g., toluenesulfonic acid). Optional steps include cooling the resin below 40°C and adding silane compounds, such as 3-aminopropyltriethoxysilane, to improve performance.
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Date
Description
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EP3530685
- Application Number
- EP19156445A
- Filing Date
- Apr 21, 2016
- Status
- Granted And Under Opposition
- Aug 8, 2025
- Publication Date
- Sep 10, 2025
- External Links
- Slate, Register , Google Patents