Abstract: A cross-linking agent with a high isocyanate content comprising a blend of diisocyanate and polyisocyanate is described. A method of cross-linking polymeric vehicles having active hydrogens, polymeric vehicles which include the cross-linking agent which includes the blend of di- and polyisocyanates and a method of making the cross-linking agent also are described.

Abstract: Low dielectric constant polyimides formed from an optionally fluorinated dianhydride and a fluorinated diamine are described. The fluorine containing constituents are sterically disposed so that the dipole moment of the constituents tend to cancel out. Since fluorine containing diamines are generally nonreactive, to achieve a polyimide of high enough molecular weight to be practically useful, a method of fabrication of a high molecular weight polymer from monomers of low reactivity is provided. The monomers, such as a diamine and dianhydride are provided in a solution within which a low molecular weight polyamic acid is formed. The solution is dried. The polyamic acid used is cured to a low molecular weight polyimide. The polyimide is redisolved, redryed and recured enough times to build up the molecular weight to a useful level. The method is applicable to fabricating other polymers of high molecular weight, such as polyamides, polyesters and polyurethanes.

Abstract: A novel catalyst system, a process for using the novel catalyst system, and a product made from the process is described. The novel catalyst system is specific for producing polyethylene terephthalate made from reacting terephthalic acid and ethylene glycol, wherein the catalyst system includes antimony; cobalt and/or zinc, and at least one of zinc, magnesium, manganese or calcium. The antimony is generally present from about 150 ppm to about 650 ppm. The cobalt and/or zinc is usually present from about 5 ppm to about 60 ppm, and the zinc, magnesium, manganese or calcium, as the third component, is generally present from about 10 ppm to about 150 ppm. The amounts of all catalyst components are based on the theoretical yield of the polymer. Using the novel catalyst system to produce PET drastically reduces the polymerization time without sacrificing color and clarity of the polymer produced.