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Enhanced Polyvinylbutyral Binder Burn-Off Via Supercritical Fluid Extraction

IP.com Disclosure Number: IPCOM000034220D
Original Publication Date: 1989-Jan-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

David, LD: AUTHOR

Abstract

This development improves binder burn-off (BBO) of polyvinylbutyral binder in a ceramic system used for semiconductor applications. The development describes a pretreatment of the binder polymer which will enchance BBO and not alter its processing into green sheets. The polyvinyl butyral binder is extracted with a supercritical fluid (SCF), and then the extracted binder is formulated into ceramic green sheets. Burnout may then take place in oxidizing atmospheres at low temperatures. The excellent solvent properties of SCF lend themselves to the purification of a binder such as polyvinylbutyral. The new porcessing method is to extract the polyvinyl butyral with either CO2 or propane, which removes impurities and antioxidants which inhibit BBO.

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Enhanced Polyvinylbutyral Binder Burn-Off Via Supercritical Fluid Extraction

This development improves binder burn-off (BBO) of polyvinylbutyral binder in a ceramic system used for semiconductor applications. The development describes a pretreatment of the binder polymer which will enchance BBO and not alter its processing into green sheets. The polyvinyl butyral binder is extracted with a supercritical fluid (SCF), and then the extracted binder is formulated into ceramic green sheets. Burnout may then take place in oxidizing atmospheres at low temperatures. The excellent solvent properties of SCF lend themselves to the purification of a binder such as polyvinylbutyral. The new porcessing method is to extract the polyvinyl butyral with either CO2 or propane, which removes impurities and antioxidants which inhibit BBO. The purified polyvinyl butyral is then processed in a slurry with the ceramic and appropriate plasticizers and solvent to form the green sheet. BBO performance increased markedly when this procedure was used. Air firing of the sheets at a temperature of N300oC for 8 hours yielded a residual carbon level of N200 ppm. This compares to a control sample using untreated polyvinylbutyral which has a carbon residue after burnoff 15 times greater than that exhibited by the purified binder. References 1 J. B. Hannay and J. Hagarth, "On the Solubility of Solids in Gases," Proc Roy Soc (London) 29, 324-326

(1879). 2 Chem & Eng News 59 31, 16-17 (August 3, 1981...