Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
2006-11-21
2008-08-12
Anderson, Rebecca L (Department: 1626)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
Reexamination Certificate
active
07411032
ABSTRACT:
A method for making polyetherimides is provided by reacting a high purity dianhydride with an aromatic diamine under condensation polymerization conditions. The dianhydrides employed are purified by a method comprising contacting a first solution containing a dianhydride compound, a solvent, and a phase transfer catalyst, with a solid inorganic adsorbent material having a total pore volume of about 0.5 milliliters/gram or greater and a cumulative pore volume distribution of about 20 percent or greater of particles having a pore diameter in a range between about 3 nanometers and about 20 nanometers. The solution containing the dianhydride compound is then separated from the solid inorganic adsorbent material to provide a purified dianhydride compound which is substantially free of the phase transfer catalyst. The purified dianhydrides are then condensed with aromatic diamines to provide polyetherimide compositions which are substantially free of residual phase transfer catalyst.
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Elliott P. Barrett et al., “The Determination of Pore Volume and Area Distributions in Porous Substances. I. Computations From Nitrogen Isotherms”, Contribution from the Multiple Fellowship of Baugh and Sons Company, Mellon Institute, vol. 73, pp. 373-380, Jan. 1951.
Hall David Bruce
Stella Albert Santo
Anderson Rebecca L
Chu Yong
SABIC Innovative Plastics IP B.V.
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