摘要:
Disclosed is a process for preparing copolymers which comprises, in the order stated: (1) adding monomers containing unsaturated carbon-to-carbon bonds, a first polymerization initiator, a second polymerization initiator, and a solvent to a reaction vessel; (2) purging the resulting solution with an inert gas; (3) sealing the reaction vessel and pressurizing it by addition of an inert gas to a pressure of from about 20 to about 600 kilopascals over ambient atmospheric pressure; (4) maintaining the temperature within the pressurized reaction vessel at a temperature of from about 50 to about 100.degree. C. for a period of from about 60 to about 300 minutes; (5) thereafter maintaining the temperature within the pressurized reaction vessel at a temperature of from about 80 to about 115.degree. C. for a period of from about 30 to about 300 minutes, wherein the temperature in step (5) is higher than the temperature in step (4); and (6) subsequently maintaining the temperature within the pressurized reaction vessel at a temperature of from about 115 to about 160.degree. C. for a period of from about 30 to about 180 minutes, wherein the temperature in step (6) is higher than the temperature in step (5). Polymers prepared according to the process of the present invention can be particularly useful in migration imaging members.
摘要:
Battery separator comprising a consolidated nonwoven mat of ultrafine polymeric fibers in which at least 10% of said fibers have a diameter less than 1 micron and which mat has an average pore size of less than 3 .mu.m. The fiber mat is formed by meltblowing using modified conditions to produce a self-bonded web having the desired content of ultra fine fibers.
摘要:
A retroreflective article comprises a) a microporous substrate (52) containing a plurality of pores (56) which are less than 0.5 μm in diameter; and b) a layer of reflective material (54) located on the surface (58) of the substrate such that the reflective material layer at least partially obscures a plurality of the pores of the substrate. A method for the production of a reflective article comprises the steps of a) providing a substrate which contains pores which have a diameter of less than 0.5 μm; and b) applying a layer of reflective material to the substrate in such a way that the reflective material layer at least partially obscures a plurality of the pores of the substrate.