Method For Constant Solids Dilution Of Polyamic Acid
Original Publication Date: 1982-Mar-01
Included in the Prior Art Database: 2005-Feb-09
A high purity polyamic acid solution having a high solids content and the desired viscosity is obtained by diluting a high molecular weight polymer with a low molecular weight polymer. For example, a high molecular weight polyamic acid, having a molecular weight of 30,000 to 40,000, a viscosity of 815 poise and 18 percent, solids, is mixed with a low molecular weight polyamic acid, having a molecular weight of less than 5,000 a viscosity of approximately 1 poise and 18 percent solids, were mixed to form a solution having a viscosity of 25 poise and 18 percent solids. The resultant solution with the high solids content provides more planarization. Preferably, the low molecular acid solution is prepared in a polypropylene container.